WO2011065148A1

WO2011065148A1 - Laser beam source apparatus

Info

Publication number: WO2011065148A1
Application number: PCT/JP2010/068241
Authority: WO
Inventors: 能徳久保田; 英之岡本; 健春日; 育成原
Original assignee: セントラル硝子株式会社
Priority date: 2009-11-24
Filing date: 2010-10-18
Publication date: 2011-06-03
Also published as: JP2011114005A

Abstract

Disclosed is a laser beam source apparatus provided with: a semiconductor light source comprising a semiconductor light emitting element that irradiates excitation light; a light emitting medium that emits light by absorbing the excitation light, and from which at least a part of the emitted light is outputted as output light; a first optical resonator that configures a first light path, which strengthens the light intensity of the excitation light by making the excitation light resonate with a first reflection element group; and a second optical resonator that configures a second light path, which strengthens the light intensity of the light emitted by the light emitting medium by making the light emitted by the light emitting medium resonate with a second reflection element group. The first light path and the second light path share a section of the light paths thereof, and the semiconductor light emitting element is arranged at the shared section. The light emitting medium is arranged at the second light path. The first reflection element group and the second reflection element group share at least the first reflection element, and the first reflection element reflects both the output light and the excitation light.

Description

Laser light source device

The present invention relates to a resonator configuration for obtaining a highly efficient laser light source device that is easy to manufacture and a laser light source device using the resonator.

As a laser light source device using a semiconductor laser as an excitation source or a fundamental wave light source, a solid-state laser having a semiconductor light source as an excitation light source, a semiconductor laser, or a wavelength conversion laser having a semiconductor laser excitation solid-state laser as a fundamental wave are known. .

As a solid-state laser excited by a semiconductor laser, there is known a method for exciting a solid-state laser material such as a crystal, glass, ceramics, or fiber added with a rare earth or a transition metal ion with a semiconductor laser or a high-power LED. Laser light is obtained. Fabry-Perot type and ring type are known as resonators for solid-state lasers. Excitation light generated by a semiconductor laser is irradiated from the outside of this resonator to a solid-state laser material through a dichroic mirror. Then, laser light is oscillated by confining light of the target laser wavelength. In the fiber laser, a solid-state laser resonator can be configured using a laser mirror or a fiber Bragg diffraction grating formed on the end face of the fiber, and the laser can be configured as an all-fiber type. In fiber lasers, a semiconductor pump light source with a fiber pigtail is often used as the pump light source. Usually, an isolator that does not return the generated fiber laser light to the semiconductor pump light source side between the semiconductor pump light source and the fiber laser material. And filters are installed. In such a laser resonator configuration, the semiconductor laser resonator that generates the excitation light and the solid-state laser resonator that generates the laser light by absorbing the excitation light are completely independent of each other.

In order to improve the mode overlap between the pumping light from the semiconductor laser and the solid-state laser light, a laser resonator configuration in which a solid-state laser medium is arranged in the semiconductor laser resonator has been proposed. (Patent Document 1).

The wavelength conversion laser is mainly used for a visible light laser or a mid-infrared wavelength band laser, which is difficult to obtain with a semiconductor laser or a solid-state laser. Non-linear wavelength conversion techniques such as second harmonic (SHG), sum frequency (SFG), and difference frequency (DFG) are used for the wavelength conversion laser. A semiconductor laser excitation solid-state laser or a semiconductor laser is used to generate the fundamental wave. Regarding the resonator configuration, in-resonator wavelength conversion has been proposed in which the fundamental wave and the wavelength-converted light are confined in the same resonator to achieve high efficiency.

In the intracavity wavelength conversion when the fundamental wave is a semiconductor laser pumped solid-state laser, a method has been proposed in which the solid-state laser medium and the nonlinear optical crystal are installed in the same resonator and pumped by the semiconductor laser from the outside of the resonator. (Patent Documents 2 to 5). In such a laser, the semiconductor laser resonator that generates the excitation light and the laser resonator on which the solid-state laser material and the nonlinear optical crystal are placed are independent of each other.

In the intracavity wavelength conversion when the fundamental wave is a semiconductor laser, a semiconductor laser material and a nonlinear optical crystal are placed in the same cavity to share the resonator, and the fundamental wave and nonlinear optical crystal emitted by the semiconductor laser have a wavelength. A method for improving efficiency by matching the modes of converted light has been proposed (Patent Document 6). In addition, the fundamental wave emitted from the semiconductor laser is confined by a resonator, and a nonlinear optical crystal is placed in the resonator to generate the second harmonic, but the wavelength-converted light is folded through the semiconductor laser. A method is also proposed in which the resonator is taken out as it is without forming a resonator (Patent Document 7).

In a wavelength conversion laser using a nonlinear optical crystal or the like, the absorption loss of the nonlinear optical crystal is sufficiently low with respect to the fundamental wave generated by the semiconductor laser, so the optical density in the nonlinear optical crystal is increased by confining the fundamental wave, Increasing the confinement of the fundamental wave, increasing the number of turns, and increasing the interaction length with the nonlinear optical crystal can increase the efficiency.

On the other hand, it is difficult to obtain sufficient laser characteristics by simply confining excitation light in a solid-state laser or fiber laser that uses a semiconductor light source as an excitation light source and uses light emitted from a solid-state laser material to which rare earth is added. . This is because the excitation light is absorbed by the rare earth or transition metal ions added as active ions to the light emitting medium, so that the absorption (loss) characteristics and light emission (gain) characteristics of the light emitting medium and the resonator configuration (feedback rate) ) Is difficult to optimize.

For example, a method using a resonator configuration method in which a solid-state laser material is placed in a semiconductor laser resonator has been proposed (Patent Document 8), and simultaneously realizes a resonance condition of a semiconductor light source and a laser resonance condition of a solid-state light emitting medium. Therefore, it is necessary to adjust the gain and loss, match the mode volume, and simultaneously adjust the optical axes, and it is difficult to achieve all of them optimally. In particular, for a semiconductor laser, a solid laser material, which is a light emitting medium, serves as an absorption medium. Therefore, only a region where the solid laser material causes absorption saturation can be used for semiconductor laser oscillation, and as a result, high-power semiconductor laser oscillation is possible. It is difficult to adjust the balance between gain and loss because it is necessary to temporarily apply an injection current or reduce the absorption of the solid-state laser material (that is, set the solid-state laser output to a low output). Even if the balance between gain and loss is successfully adjusted, the laser saturation must take into account the absorption saturation characteristics of the solid-state laser material. Therefore, except for the specific excitation power or the specific output that the solid-state laser material emits. It will deviate from the optimal laser resonator conditions.

In a solid-state laser using a solid-state laser material and a general spatial optical system, the optical resonator of the semiconductor light source and the optical resonator of the solid-state laser material are independent of each other and are independent of each other in terms of optical arrangement. Adjustments must also be made independently. For this reason, when trying to obtain the desired output light by condensing and irradiating the solid-state laser material with the excitation light from the semiconductor light source, optimization of the optical component position of the laser resonator of the solid-state laser and the coupling efficiency of the excitation light In order to achieve both optimization, complicated optical component position adjustment is necessary, and it is difficult to construct an optimal resonator.

In addition, a tunable laser with a visible broadband and a broadband wavelength has been proposed by using a GaN-based semiconductor laser as a semiconductor laser and using a ZBLAN fiber doped with Pr ³⁺ as a light-emitting medium (Non-patent Document 1).

Japanese Patent Laid-Open No. 06-112560 Japanese Patent Laid-Open No. 7-106682 JP-A-7-104332 JP-A-6-350168 Japanese Patent Laid-Open No. 5-95145 JP-A-6-112560 JP-A-62-86881 JP-A-6-112560

As described above, in a solid-state laser or fiber laser using a semiconductor light source as an excitation light source and utilizing light emitted from a solid-state laser material to which rare earth or the like is added, the absorption (loss) characteristics and emission (gain) characteristics of the light-emitting medium, It is difficult to optimize the resonator configuration (feedback rate), and in order to achieve both optimization of the optical component position of the laser resonator of the solid-state laser and optimization of the coupling efficiency of the pumping light Therefore, complicated optical component position adjustment is necessary.

The present invention enables not only high-efficiency excitation of a light-emitting medium by a semiconductor light source and high-efficiency light emission by optimizing a plurality of resonators, but also easy optical position adjustment to optimize the performance of the light source. Therefore, an object of the present invention is to provide a laser light source device that can easily realize a light source device having high luminance and high light emission efficiency.

As a result of intensive studies on the above problems, the present inventors have used a solid state laser in a laser light source device that uses a semiconductor light source as an excitation source and extracts the output of a solid laser material that emits light by absorbing the excitation light. Are separate from the optical resonators of the semiconductor laser and share at least one highly reflective reflective element in the optical path of each resonator, and the emitted light from the solid-state laser material in the semiconductor laser The inventors have come up with the present invention by thinking that the problem can be solved by adopting a structure that passes through the semiconductor chip.

That is, the present invention relates to a semiconductor light source including a semiconductor light emitting element that emits excitation light, and a light emitting medium that emits light by absorbing the excitation light, and at least part of the light emission is output as output light. A medium, a first optical resonator configured by a first reflection element set to resonate the excitation light and enhance its light intensity, and a light source of the light emitting medium to resonate and enhance the light intensity A laser light source device including a second optical resonator that constitutes a second optical path by a second reflecting element set, wherein the first optical path and the second optical path share a part, and the semiconductor light emitting device is shared by the shared portion. An element is disposed, the light emitting medium is disposed in the second optical path, the first reflective element set and the second reflective element set share at least the first reflective element, and the first reflective element is coupled with the output light. A laser light source device that reflects the excitation light together is provided.

Further, both the first optical resonator and the second optical resonator are Fabry-Perot optical resonators, and the first reflective element group includes a second reflective element other than the first reflective element. The second reflection element constitutes a light emitting end of the first optical resonator, and the second reflection element has a reflectance of light having a desired oscillation wavelength of the first optical resonator. The second reflective element set has a third reflective element other than the first reflective element, and the third reflective element constitutes a light emitting end of the second optical resonator, and the third reflective element Provides a laser light source device in which the reflectance of light having a desired oscillation wavelength of the second optical resonator is lower than that of the first reflecting element.

1 shows a schematic diagram of a first embodiment according to the invention. FIG. 2 shows a schematic diagram of a second embodiment according to the present invention. FIG. 3 shows a schematic diagram of a third embodiment according to the present invention. FIG. 6 shows a schematic diagram of a fourth embodiment according to the present invention. FIG. 7 shows a schematic diagram of a fifth embodiment according to the present invention. FIG. 10 is a schematic diagram of a sixth embodiment according to the present invention. FIG. 10 is a schematic view of a seventh embodiment according to the present invention. FIG. 10 is a schematic diagram of an eighth embodiment according to the present invention. FIG. 10 is a schematic view of a ninth embodiment according to the present invention. FIG. 10 shows a schematic diagram of a tenth embodiment according to the present invention. The schematic of the apparatus used for the comparative example 1 is shown. The schematic of the apparatus used for the comparative example 2 is shown.

According to the present invention, it is possible to easily obtain a laser light source device that can easily adjust the optical position for optimizing the performance of the light source, has high brightness of the obtained laser light, and has high luminous efficiency.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The arrangement of the laser light source device according to the first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, a semiconductor light emitting device 4 is used as an excitation light source, and a light emitting medium 5 that absorbs the excitation light and emits light having a wavelength different from that of the excitation light is provided to enhance the light of the semiconductor optical device 4 that generates the excitation light. As a resonator for performing the above, a semiconductor laser resonator 1 (first optical resonator) including the reflecting element 6, the reflecting element 7, and the reflecting element 8, and a resonator for enhancing light emission from the light emitting medium 5 are reflected. The solid-state laser resonator 2 (second optical resonator) including the element 6, the reflective element 9, and the reflective element 10 is provided. The semiconductor laser resonator 1 (first optical resonator) and the solid-state laser resonator 2 (second light) are provided. The resonator) shares a part of the optical path with the reflective element 6 (first reflective element), and the semiconductor light emitting element 4 that emits the excitation light is installed in the shared optical path. A light-emitting medium 5 is installed in an optical path that is not shared It has been.

Furthermore, the reflective element 6 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 4 and the light emission wavelength from the light emitting medium 5 as an optical path conversion mirror. Is a reflection element that partially reflects the excitation light generated in the semiconductor light emitting element 4 and transmits light having the emission wavelength of the light emitting medium 5. The reflection element 8 is a reflection that highly reflects the excitation light generated in the semiconductor light emitting element 4. The reflective element 9 is a reflective element that highly transmits excitation light generated by the semiconductor light emitting element 4 as a dichroic mirror and highly reflects light having the emission wavelength of the light emitting medium 5. The reflective element 10 is a light emitting medium 5. It is a reflective element that partially reflects and partially transmits light having the emission wavelength of.

The luminescent medium 5 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 7. The emitted fluorescence is amplified and oscillates as it circulates in the ring-shaped resonator (solid laser resonator 2) composed of the reflective element 6, the reflective element 9, and the reflective element 10. Part of the oscillated laser light is output 3 through the reflecting element 10 to the outside.

According to the first embodiment described above, the following operational effects are achieved.

First, the semiconductor laser resonator 1 (first optical resonator) is optimized to maximize the pumping light intensity, and then the shared optical path with the semiconductor laser resonator 1 and the shared reflecting element 6 (first reflecting element) are fixed. The light output can be easily maximized by optimizing the position of the light emitting medium 5 and the position and angle of the reflecting element 10 (non-shared reflecting element) of the solid-state laser resonator 2 (second optical resonator). Can be planned. At this time, even if the solid-state laser resonator 2 is being adjusted, the semiconductor laser resonator 1 is not affected because it is an independent resonator. Further, since the solid-state laser resonator 2 is supplied with the excitation light with the optimized output from the optimized semiconductor laser resonator 1, the light emitting medium 5 can emit strong light.

Furthermore, in order for the solid-state laser resonator 2 to start laser oscillation, it is necessary that the optical axis is coincident with or sufficiently close to the shared portion with the semiconductor laser resonator 1. This is because absorption and scattering are caused by the semiconductor light emitting element in the semiconductor laser resonator 1 except for the vicinity of the optical axis of the semiconductor laser that oscillates in the semiconductor laser resonator 1, and the solid laser resonator 2 has a low loss. It is because it does not become. Due to this effect, when the solid-state laser resonator 2 is adjusted to perform laser oscillation, the optical axes of the semiconductor laser resonator 1 are naturally aligned at the same time. That is, when the optical axes of the semiconductor laser resonator 1 and the solid-state laser resonator 2 are coincident or close to each other, the oscillation wavelength of the laser light generated by the solid-state laser resonator 2 and the wavelength of the excitation light generated by the semiconductor laser resonator 1 This makes it easy to maximize mode overlap. In order to maximize the mode overlap at both wavelengths, the incident optical system in which the excitation light is incident on the light emitting medium 5 and the reflecting element 10 (non-shared reflecting element) of the solid-state laser resonator 2 and the light emitting medium. The target laser output can be maximized by adjusting the distance in the direction of the optical axis 5 and adjusting the diameter of the focused spot on the light emitting medium 5 and the focal length. Therefore, the optical system can be easily adjusted by simple optical adjustment, and a laser light source device having high luminance and high light emission efficiency can be easily realized.

Further, a second embodiment in which the configuration of the resonator shown in FIG. 1 is further simplified will be described with reference to FIG. In addition, description of the part which is common in FIG. 1 is abbreviate | omitted.

As a resonator for enhancing the light of the semiconductor optical element 204 that generates the excitation light, the semiconductor laser resonator 201 (first optical resonator) composed of the reflective element 206 and the reflective element 207 and the light emission from the light emitting medium 205 are emitted. As a resonator for enhancing, a solid-state laser resonator 202 (second optical resonator) composed of a reflective element 206 (first reflective element) and a reflective element 210 is provided. A Fabry-Perot type semiconductor laser resonator 201 is installed so as to share one reflection element (reflection element 206) of the solid-state laser resonator 202. The configuration shown in FIG. 2 has a simplified configuration in which the reflective elements corresponding to the

reflective elements

8 and 9 in FIG. 1 are removed, and the number of components is smaller than that in FIG.

The light emitting medium 205 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 207. Fluorescence emitted from the light emitting medium 205 is confined between the reflective element 206 and the reflective element 206 shared with the reflective element 210 and is enhanced while reciprocating, and laser oscillation occurs. A part of the oscillated laser beam is output 203 through the reflecting element 210 to the outside.

According to the second embodiment described above, the following effects are obtained. The same effect as the first embodiment can be obtained. Furthermore, the optical system can be easily adjusted by simpler optical adjustment than in the first embodiment.

Although not specifically shown in the drawings in the first embodiment and the second embodiment of the present invention, excitation light is emitted between the reflective element 7 and the light emitting medium 5 and between the reflective element 207 and the light emitting medium 205. A lens for condensing and irradiating the medium can be added. This lens is preferably provided with a broadband non-reflective coating that is low-reflective in both oscillating laser light and excitation light. Further, as the lens, it is preferable to use an achromatic lens or an aspherical lens in which the focal length is approximately equal between the wavelength of the oscillating laser light and the wavelength of the excitation light and the aberration is suppressed. Further, instead of such a lens, the light emitting medium 5 side of the reflecting element 7 and the light emitting medium 205 side of the reflecting element 207 may have a convex lens shape to have a function of condensing excitation light on the light emitting medium.

Furthermore, since the form of an optical waveguide can be used as the light emitting medium, a third embodiment in the case of using a light emitting medium in the form of a fiber which is one of the forms of the optical waveguide will be described with reference to FIG. To do.

In FIG. 3, the semiconductor light-emitting element 304 is used as an excitation light source, and includes a fiber-type light-emitting medium 305 that absorbs the excitation light and emits light having a wavelength different from that of the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 301 (first optical resonator) composed of a reflective element 306 and a reflective element 313, and as a resonator for enhancing light emission from the light emitting medium 305, a reflective element 306 (first reflective element) and a solid state laser resonator 302 (second optical resonator) composed of the reflective element 314, and a semiconductor laser resonator 301 (first optical resonator) and a solid state laser resonator 302 (second optical resonator). The optical resonator) shares a part of the optical path with the reflecting element 306, and a semiconductor light emitting element 304 that emits excitation light is installed in the shared optical path. Emitting medium 305 is installed in the 02 optical path that is not shared.

Furthermore, the reflective element 306 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 304 and the light emission wavelength from the light emitting medium 305 as a shared mirror. The reflective element that transmits light of the emission wavelength of the light emitting medium 305 and the surface of the semiconductor light emitting element 304 side partially reflects the excitation light generated by the semiconductor light emitting element 304. The shape of the reflective element 313 on the light emitting medium 305 side is The lens has a convex lens shape so that excitation light can be condensed on the excitation side end surface 315 of the light emitting medium 305. Further, the light emitted from the light emitting medium 305 in the form of a fiber is arranged so as to be roughly coupled to the active layer of the semiconductor light emitting element 304.

The reflecting element 314 is formed by directly forming an optical thin film that partially reflects the fluorescence from the light emitting medium 305 on the end surface of the light emitting medium 305 opposite to the semiconductor light emitting element 304 or by forming a transparent film on which the optical thin film is formed. It is equipped by bonding, optical contact or fusing the substrates.

The luminescent medium 305 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 313. The fluorescence from the light emitting medium 305 is enhanced while reciprocating between the reflecting element 314 and the reflecting element 306, and laser oscillation occurs. Part of the oscillated laser beam is output 303 through the reflecting element 314 to the outside.

The excitation-side end face 315 is provided with a broadband non-reflective coating that has low reflectance at both the excitation light wavelength and the oscillated laser light wavelength.

According to the third embodiment described above, the following effects are obtained.

First, the semiconductor laser resonator 301 (first optical resonator) is optimized to maximize the pumping light intensity. Thereafter, the input end 315 of the optical waveguide is adjusted in the vicinity of the focal point of the reflective element 313 having a condensing function while the shared optical path with the semiconductor laser resonator 301 and the shared reflective element 306 (first reflective element) are fixed. The angle is adjusted so that the output of the semiconductor laser is roughly coupled to the fiber core. Since the light emitting medium 305 has a waveguide shape and already has a reflecting element 314 that is an output partial reflecting mirror of the solid-state laser resonator 302 at one end, half of the resonator is coupled with excitation light. It is completed with. Thereafter, when the output 303 is monitored and the angle of the input end 315 is mainly adjusted to maximize the output, laser oscillation can be easily obtained. At this time, not only the laser oscillation but also the optical axes of the semiconductor laser resonator 301 and the solid-state laser resonator 302 automatically coincide with each other automatically for the same reason as described in the first embodiment. To do. For this reason, not only laser oscillation is easy, but also maximum output and high efficiency by maximizing mode overlap can be achieved at the same time. Therefore, even when the light emitting medium has a waveguide shape, the optical system can be easily adjusted by simple optical adjustment, and a laser light source device having high luminance and high light emission efficiency can be easily realized.

As another example of using a light emitting medium in the form of a fiber, a fourth embodiment will be described with reference to FIG.

In FIG. 4, a semiconductor light-emitting element 404 that uses a semiconductor light-emitting element 404 as an excitation light source, includes a fiber-shaped light-emitting medium 405 that absorbs the excitation light and emits light having a wavelength different from that of the excitation light, and generates the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 401 (first optical resonator) composed of a reflective element 406 (first reflective element) and a reflective element 413, and light emission from a light emitting medium 405 are enhanced. As a resonator, a solid-state laser resonator 402 (second optical resonator) including a reflective element 406 and a reflective element 414 is provided, and a semiconductor laser resonator 401 (first optical resonator) and a solid-state laser resonator 402 (second optical resonator). The optical resonator) shares a part of the optical path with the reflecting element 406, and a semiconductor light emitting element 404 that emits excitation light is installed in the shared optical path. Emitting medium 405 is installed in the 02 optical path that is not shared.

Further, the reflective element 406 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 404 and the light emission wavelength from the light emitting medium 405 as a shared mirror. A reflective element that partially reflects the excitation light generated in the semiconductor light emitting element 404 and transmits light having the emission wavelength of the light emitting medium 405, and has a dielectric multilayer film or Fresnel reflection formed directly on the end face of the semiconductor light emitting element 404. The cleaved end face used. The semiconductor light emitting element side end surface 416 of the light emitting medium 405 is polished into a lens shape so as to collect the excitation light from the semiconductor light emitting element 404 and couple the light emitted from the light emitting medium 405 to the active layer of the semiconductor light emitting element 404. The semiconductor light emitting device 404 is disposed in proximity to the active layer.

In the reflective element 414, an optical thin film that partially reflects the fluorescence from the light emitting medium 405 is formed directly on the end surface of the light emitting medium 405 opposite to the semiconductor light emitting element 404, or a transparent film on which the optical thin film is formed. It is equipped by bonding, optical contact or fusing the substrates.

The luminescent medium 405 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 413. The fluorescence from the light emitting medium 405 is enhanced while reciprocating between the reflecting element 414 and the reflecting element 406, and laser oscillation occurs. A part of the oscillated laser beam is output 403 to the outside through the reflecting element 414.

The excitation-side end face 416 is provided with a broadband non-reflective coating that has a low reflectance at both the excitation light wavelength and the oscillated laser light wavelength.

According to the fourth embodiment described above, the following effects are obtained.

The same effect as the third embodiment can be obtained. Further, by using a so-called lensed fiber having a lens-shaped incident end surface, the coupling optical system for coupling the excitation light radiated from the semiconductor laser resonator 401 to the light emitting medium 405 can be reduced in size. Further, by downsizing the optical coupling portion, the optical coupling portion can be easily and firmly fixed, and the coupling efficiency can be prevented from changing or changing due to vibration or temperature change.

As another example of using a light emitting medium in the form of a fiber, a fifth embodiment will be described with reference to FIG.

In FIG. 5, a semiconductor light-emitting element 504 is used as an excitation light source, and includes a fiber-type light-emitting medium 505 that absorbs the excitation light and emits light having a wavelength different from that of the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 501 (first optical resonator) composed of a reflective element 506 (first reflective element) and a reflective element 513, and light emission from a light emitting medium 505 are enhanced. As a resonator, a solid-state laser resonator 502 (second optical resonator) including a reflective element 506 and a reflective element 514 is provided. The reflective element 514 includes an output fiber 517, and a semiconductor laser resonator 501 (first optical resonator). ) And the solid-state laser resonator 502 (second optical resonator) share a part of the optical path with the reflecting element 506, and a semiconductor light emitting element that emits excitation light in the shared optical path. 504 is installed, the light emitting medium 505 in the optical path that is not shared the solid-state laser resonator 502 is installed.

Further, the reflective element 506 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 504 and the light emission wavelength from the light emitting medium 505 as a shared mirror. The reflective element that transmits light of the emission wavelength of the light emitting medium 505 and that partially reflects the excitation light generated by the semiconductor light emitting element 504 is the reflective element 513 on the light emitting medium 505 side. The light emitting medium 505 has a convex lens shape so that the excitation light can be condensed on the excitation side end surface 515. Further, the light emitted from the light emitting medium 505 in the fiber form is arranged so as to be roughly coupled to the active layer of the semiconductor light emitting element 504.

On the end surface of the light emitting medium 505 opposite to the semiconductor light emitting element 504 side, the reflecting element 514 of the output fiber 517 in which the reflecting element 514 that partially reflects the fluorescence from the light emitting medium 505 is directly formed on the end surface is formed. The end faces are fusion spliced.

The luminescent medium 505 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 513. The fluorescence from the light emitting medium 505 is enhanced while reciprocating between the reflecting element 514 and the reflecting element 506, and laser oscillation occurs. Part of the oscillated laser light propagates to the output fiber 517 through the reflecting element 514 and is output 503 from the end face of the output fiber 517 to the outside.

The excitation-side end surface 515 is provided with a broadband non-reflective coating that has a low reflectance at both the excitation light wavelength and the oscillated laser light wavelength.

According to the fifth embodiment described above, the following effects are obtained.

The same effect as the third embodiment can be obtained. Further, since there is no reflecting element constituting the solid-state laser resonator 502 at the end of the output fiber 517 on the output 503 side, and the reflecting element 514 is protected by the fused portion, it is excellent in environmental resistance and durability. In particular, when the light emitting medium 505 has a problem in environmental resistance, it is possible to prevent the light emitting medium 505 from being deteriorated by exposing only the output fiber 517 from the hermetic seal housing.

As another example of using a light emitting medium in the form of a fiber, a sixth embodiment will be described with reference to FIG.

In FIG. 6, a semiconductor light-emitting element 604 is used as an excitation light source, and includes a light-emitting medium 605 in the form of a fiber that absorbs the excitation light and emits light having a wavelength different from that of the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 601 (first optical resonator) composed of a reflective element 606 (first reflective element) and a reflective element 613, and light emission from a light emitting medium 605 are enhanced. As a resonator, a solid-state laser resonator 602 (second optical resonator) including a reflective element 606 and a reflective element 614 is provided, and a semiconductor laser resonator 601 (first optical resonator) and a solid-state laser resonator 602 (second optical resonator). The optical resonator) shares a part of the optical path with the reflecting element 606, and a semiconductor light emitting element 604 that emits excitation light is installed in the shared optical path. Emitting medium 605 is installed in the 02 optical path that is not shared.

Furthermore, the reflective element 606 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 604 and the light emission wavelength from the light emitting medium 605 as a shared mirror. , A reflective element that transmits light of the emission wavelength of the light emitting medium 605 and partially reflects the excitation light generated by the semiconductor light emitting element 604. The dielectric multilayer film or the Fresnel reflection directly formed on the end face of the semiconductor light emitting element 604 The cleaved end face used. An input fiber 618 is fused and connected to the semiconductor light emitting element side of the light emitting medium 605 at a fusion point 619, and an end surface 616 of the input fiber 618 on the semiconductor light emitting element 604 side receives excitation light from the semiconductor light emitting element 604. The light is condensed and polished into a lens shape so as to couple light emitted from the light emitting medium 605 to the active layer of the semiconductor light emitting element 604, and is disposed close to the active layer of the semiconductor light emitting element 604. On the end face of the light emitting medium 605 opposite to the input fiber 618 side, a reflective element 614 that partially reflects the fluorescence from the light emitting medium 605 is formed directly, or an optical thin film is formed. It is equipped by bonding, optical contact or fusing a transparent substrate.

The input fiber 618 can propagate light emitted from the light emitting medium 605 and excitation light generated from the semiconductor light emitting element 604 bidirectionally with low loss. Excitation light propagating through the input fiber 618 is coupled to the core of the light emitting medium 605 in the form of a fiber through a fusion point 619.

The luminescent medium 605 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 613. Fluorescence from the luminescent medium 605 is enhanced while reciprocating between the reflective element 614 and the reflective element 606, and lasing. Part of the oscillated laser beam is output 603 to the outside through the reflecting element 614.

The end face 616 of the input fiber 618 is provided with a broadband non-reflective coating that has a low reflectance at both the excitation light wavelength and the oscillated laser light wavelength.

According to the sixth embodiment described above, the following effects are obtained.

The same effect as the fourth embodiment can be obtained. Furthermore, since the input fiber 618 can be a fiber different from the light emitting medium 605, a general-purpose optical component such as a lensed fiber using quartz can be used. For this reason, when the light emitting medium 605 is, for example, a fluoride fiber, the processing is not always easy. Therefore, the processing yield of the product can be improved, and the manufacturing cost can be suppressed by using inexpensive general-purpose parts.

As another example of using a light emitting medium in the form of a fiber, a seventh embodiment will be described with reference to FIG.

In FIG. 7, a semiconductor light-emitting element 704 is used as an excitation light source, and includes a light emitting medium 705 in a fiber form that absorbs the excitation light and emits light having a wavelength different from that of the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 701 (first optical resonator) composed of a reflective element 706 (first reflective element) and a reflective element 713, and light emission from a light emitting medium 705 are enhanced. As a resonator, a solid-state laser resonator 702 (second optical resonator) including a reflective element 706 and a reflective element 714 is provided. The reflective element 714 includes an output fiber 717, and a semiconductor laser resonator 701 (first optical resonator). ) And the solid-state laser resonator 702 (second optical resonator) share a part of the optical path with the reflecting element 706, and a semiconductor light emitting element that emits excitation light in the shared optical path. 704 is installed, the light emitting medium 705 in the optical path that is not shared the solid-state laser resonator 702 is installed.

Further, the reflective element 706 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 704 and the light emission wavelength from the light emitting medium 705 as a shared mirror. The light emitting medium 705 transmits light having the emission wavelength, and the surface on the semiconductor light emitting element 704 side is a reflective element that partially reflects the excitation light generated by the semiconductor light emitting element 704. The light emitting medium 705 has a surface on the semiconductor light emitting element 704 side. The input fiber 718 is fusion spliced at a fusion point 719, and the end surface 715 of the input fiber 718 on the semiconductor light emitting element 704 side has a low reflectance at both the excitation light wavelength and the oscillated laser light wavelength. Reflective coating is applied, and the shape of the reflective element 713 on the side of the light emitting medium 705 is the same as that of the input fiber 7 fused and connected to the excitation side of the light emitting medium 705. It has a convex shape so that the excitation light can condensing on the end face 715 of the 8. The reflection element 713 can collect the excitation light on the end face 715 and is disposed so as to couple the light having the emission wavelength from the fiber type light emitting medium 705 propagating through the input fiber 718 to the active layer of the semiconductor light emitting element 704. Has been.

The input fiber 718 can propagate light emitted from the light emitting medium 705 and excitation light generated from the semiconductor light emitting element 704 bidirectionally with low loss. Excitation light propagating through the input fiber 718 is coupled to the core of the light emitting medium 705 in the form of a fiber through a fusion point 719.

On the end face of the light emitting medium 705 opposite to the semiconductor light emitting element 704 side, the reflecting element 714 of the output fiber 717 in which the reflecting element 714 that partially reflects the fluorescence from the light emitting medium 705 is directly formed on the end face is formed. The end faces are fusion spliced.

The light emitting medium 705 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 713. The fluorescence from the light emitting medium 705 is enhanced while reciprocating between the reflecting element 714 and the reflecting element 706, and laser oscillation occurs. Part of the oscillated laser light propagates to the output fiber 717 through the reflecting element 714 and is output 703 from the end face of the output fiber 717 to the outside.

According to the seventh embodiment described above, the following effects are obtained.

The same effect as the fifth embodiment can be obtained. Furthermore, since the input fiber 718 provided with the input end 715 can be a fiber different from the light emitting medium 705, a general-purpose optical component such as a film-formed quartz fiber can be used. For this reason, when the light-emitting medium 705 is, for example, a fluoride fiber, it may not always be easy to form an optical thin film directly on the end face. Manufacturing costs can be reduced.

As another example of using a light emitting medium in the form of a fiber, an eighth embodiment will be described with reference to FIG.

In FIG. 8, a semiconductor light emitting element 804 is used as an excitation light source, and includes a light emitting medium 805 in the form of a fiber that absorbs the excitation light and emits light having a wavelength different from that of the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 801 (first optical resonator) composed of a reflective element 806 (first reflective element) and a reflective element 813, and light emission from a light emitting medium 805 are enhanced. As a resonator, a solid-state laser resonator 802 (second optical resonator) including a reflective element 806 and a reflective element 814 is provided. The reflective element 814 includes an output fiber 817, and a semiconductor laser resonator 801 (first optical resonator). ) And the solid-state laser resonator 802 (second optical resonator) share a part of the optical path with the reflecting element 806, and a semiconductor light emitting element that emits excitation light in the shared optical path 804 is installed, the light emitting medium 805 in the optical path that is not shared the solid-state laser resonator 802 is installed.

Furthermore, the reflective element 806 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 804 and the light emission wavelength from the light emitting medium 805 as a shared mirror. The reflective element 813 is a reflective element that transmits the light having the emission wavelength of the light emitting medium 805 and partially reflects the excitation light generated by the semiconductor light emitting element 804. The dielectric multilayer film directly formed on the end face of the semiconductor light emitting element 804 Or it is a cleave end face using Fresnel reflection. An input fiber 818 is fused and connected to the semiconductor light emitting element 804 side of the light emitting medium 805 at a fusion point 819, and an end face 816 of the input fiber 818 on the semiconductor light emitting element 804 side is excited light from the semiconductor light emitting element 804. Is collected in a lens shape so as to couple light emitted from the light emitting medium 805 to the active layer of the semiconductor light emitting element 804, and is disposed close to the active layer of the semiconductor light emitting element 804.

The input fiber 818 can propagate light emitted from the light emitting medium 805 and excitation light generated from the semiconductor light emitting element 804 bidirectionally with low loss. Excitation light propagating through the input fiber 818 is coupled to the core of the light emitting medium 805 in the form of a fiber through a fusion point 819.

On the end surface of the light emitting medium 805 opposite to the semiconductor light emitting element 804 side, the reflecting element 814 of the output fiber 817 in which the reflecting element 814 that partially reflects the fluorescence from the light emitting medium 805 is directly formed on the end surface is formed. The end faces are fusion spliced.

The luminescent medium 805 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 813. Fluorescence from the light emitting medium 805 is enhanced while reciprocating between the reflecting element 814 and the reflecting element 806, and lasing. Part of the oscillated laser beam is output 803 to the outside through the reflecting element 814.

The end face 816 of the input fiber 818 is provided with a broadband non-reflective coating that has low reflectivity at both the excitation light wavelength and the oscillated laser light wavelength.

According to the above eighth embodiment, the following operational effects are obtained.

The same effect as in the sixth embodiment can be obtained. Furthermore, since there is no reflecting element constituting the solid-state laser resonator 802 at the end of the output fiber 817 on the output 803 side, and the reflecting element 814 is protected by the fused portion, it is excellent in environmental resistance and durability. In particular, when the light emitting medium 805 has a problem in environmental resistance, it is possible to prevent deterioration of the light emitting medium 805 by exposing only the output fiber 817 from the hermetic seal housing.

As another example of using a light emitting medium in the form of a fiber, a ninth embodiment will be described with reference to FIG.

In FIG. 9, a semiconductor light-emitting element 904 is used as an excitation light source, and includes a light-emitting medium 905 in the form of a fiber that absorbs the excitation light and emits light having a wavelength different from that of the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 901 (first optical resonator) composed of a reflective element 906 (first reflective element) and a reflective element 913, and light emission from a light emitting medium 905 are enhanced. As a resonator, a solid-state laser resonator 902 (second optical resonator) including a reflecting element 906 and a reflecting element 920 is provided, and the reflecting element 920 is fused to the end surface of the light emitting medium 905 opposite to the semiconductor optical element 904 side. The semiconductor laser resonator 901 (first optical resonator) and the solid-state laser resonator 902 (second optical resonator) are connected to each other at a point 919 by a reflection element 906 and a part of the optical path. Share and are semiconductor light emitting element 904 is disposed to emit excitation light to the shared optical path, the light emitting medium 905 is installed in the optical path that is not shared the solid-state laser resonator 902.

Further, the reflective element 906 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 904 and the light emission wavelength from the light emitting medium 905 as a shared mirror. The light emitting medium 905 transmits light of the emission wavelength, and the surface on the semiconductor light emitting element 904 side is a reflective element that partially reflects the excitation light generated by the semiconductor light emitting element 904. The input fiber 918 is fusion spliced at a fusion point 921, and the end surface 915 of the input fiber 918 on the semiconductor light emitting element 904 side has a low reflectance at both the pumping light wavelength and the oscillated laser light wavelength. Reflective coating is applied, and the shape of the reflective element 913 on the side of the light emitting medium 905 is the same as that of the input fiber 9 fused and connected to the excitation side of the light emitting medium 905. It has a convex shape so that the excitation light can condensing on the end face 915 of the 8. The reflection element 913 is arranged so that excitation light can be collected on the end face 915 and light of the emission wavelength from the fiber type light emitting medium 905 propagating through the input fiber 918 is coupled to the active layer of the semiconductor light emitting element 904. Has been.

The input fiber 918 can propagate light emitted from the light emitting medium 905 and excitation light generated from the semiconductor light emitting element 904 bidirectionally with low loss. Excitation light propagating through the input fiber 918 is coupled to the core of the light emitting medium 905 in the form of a fiber through a fusion point 921.

The reflection element 920 is a fiber diffraction grating that partially reflects light having the emission wavelength of the light emitting medium 905, and includes an output fiber 917 on the side that is not fusion-bonded to the light emitting medium 905.

The light emitting medium 905 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 913. Fluorescence from the light emitting medium 905 is enhanced while reciprocating between the reflective element 920 and the reflective element 906, and lasing. Part of the oscillated laser light propagates to the output fiber 917 through the reflection element 920 and is output 903 from the end face of the output fiber 917 to the outside.

According to the ninth embodiment described above, the following effects are obtained.

The same effect as the seventh embodiment can be obtained. Further, since the reflection element 920 of the solid-state laser resonator 902 is a fiber diffraction grating, it can be easily made a reflection element having a narrow-band reflection characteristic even in the visible light wavelength region, and is small and has a small excess loss. A resonator is configured, and a solid laser with high efficiency and high output can be easily realized.

The tenth embodiment will be described with reference to FIG. 10 as another example of using a light emitting medium in the form of a fiber.

In FIG. 10, a semiconductor light emitting device 1004 that uses a semiconductor light emitting device 1004 as an excitation light source, includes a fiber-type light emitting medium 1005 that absorbs the excitation light and emits light having a wavelength different from that of the excitation light, and generates the excitation light. As a resonator for enhancing light, a semiconductor laser resonator 1001 (first optical resonator) composed of a reflective element 1006 (first reflective element) and a reflective element 1013, and light emission from a light emitting medium 1005 are enhanced. As a resonator, a solid-state laser resonator 1002 (second optical resonator) including a reflecting element 1006 and a reflecting element 1020 is provided, and the reflecting element 1020 is fused to an end surface of the light emitting medium 1005 opposite to the semiconductor optical element 1004 side. The semiconductor laser resonator 1001 (first optical resonator) and the solid-state laser resonator 1002 (second optical resonator) are fusion-spliced at a point 1019. A part of the optical path is shared with the reflecting element 1006, a semiconductor light emitting element 1004 that emits excitation light is installed in the shared optical path, and a light emitting medium is installed in the unshared optical path of the solid-state laser resonator 1002. 1005 is installed.

Furthermore, the reflective element 1006 (first reflective element) is a reflective element that highly reflects both the excitation light wavelength from the semiconductor light emitting element 1004 and the light emission wavelength from the light emitting medium 1005 as a shared mirror. The reflective element 1013 is a reflective element that transmits light having the emission wavelength of the light emitting medium 1005 and partially reflects the excitation light generated by the semiconductor light emitting element 1004. The dielectric multilayer film directly formed on the end face of the semiconductor light emitting element 1004 Or it is a cleave end face using Fresnel reflection. An input fiber 1018 is fused and connected to the semiconductor light emitting element 1004 side of the light emitting medium 1005 at a fusion point 1021, and an end surface 1016 of the input fiber 1018 on the semiconductor light emitting element 1004 side is excited light from the semiconductor light emitting element 1004. Is collected in a lens shape so as to couple light emitted from the light emitting medium 1005 to the active layer of the semiconductor light emitting element 1004, and is disposed close to the active layer of the semiconductor light emitting element 1004.

The input fiber 1018 can propagate light emitted from the light emitting medium 1005 and excitation light generated from the semiconductor light emitting element 1004 bidirectionally with low loss. The excitation light propagating through the input fiber 1018 is coupled to the core of the light emitting medium 1005 in the form of a fiber through the fusion point 1021.

The reflection element 1020 is a fiber diffraction grating that partially reflects light having the emission wavelength of the light emitting medium 1005, and includes an output fiber 1017 on the side not fused to the light emitting medium 1005.

The luminescent medium 1005 emits fluorescence generated by absorbing the excitation light transmitted through the reflecting element 1013. The fluorescence from the light emitting medium 1005 is enhanced while reciprocating between the reflective element 1020 and the reflective element 1006, and laser oscillation occurs. Part of the oscillated laser light propagates to the output fiber 1017 through the reflecting element 1020, and is output 1003 from the end face of the output fiber 1017 to the outside.

The end face 1016 of the input fiber 1018 is provided with a broadband non-reflective coating that has low reflectivity at both the excitation light wavelength and the oscillated laser light wavelength.

According to the tenth embodiment described above, the following effects are obtained.

The same effect as in the eighth embodiment can be obtained. Further, since the reflecting element 1020 of the solid-state laser resonator 1002 is a fiber diffraction grating, not only can the reflecting element have a narrow-band reflecting characteristic even in the visible light wavelength region, but also a small resonator with less excess loss. It is possible to easily realize a high-efficiency and high-power solid-state laser.

In the fourth, sixth, eighth, and tenth embodiments described above, the lens shape of the end surface for inputting the excitation light on the semiconductor light emitting element side of the light emitting medium may be a tapered lens, a tip cylindrical lens shape, a compound cylindrical lens shape, or the like. A shape that easily couples light having a large difference in divergence angle between the right and left directions to the core of the optical fiber is preferable.

In the above third to tenth embodiments, it is preferable that the broadband non-reflective coating to be applied has both the reflectance of the oscillated laser light wavelength and the excitation light wavelength of 1% or less. In general, dielectric film coating such as vapor deposition and sputtering is common, but wet coating such as resin coating and organic-inorganic hybrid film coating can also be used.

In the third to eighth embodiments, it is preferable to use a dielectric multilayer coating for the reflective element installed on the output side of the light emitting medium. However, depending on the wavelength characteristics and reflectance, a metal film or an alloy film is used. Further, a film using fullerenes such as carbon nanotubes or a coating film containing semiconductor nanoparticles can be used.

In the third, fourth, and sixth embodiments, when a transparent substrate on which an optical thin film is formed as a reflective element that is bonded, optically contacted, or fused to the output side of the light emitting medium is used, at least as the transparent substrate It is necessary to be transparent to the oscillation wavelength output to the outside, and it is preferable to use a glass substrate or a crystallized glass substrate.

In the fifth, seventh, and eighth embodiments, when the end face of the output fiber on which the reflecting element is formed is fusion-bonded to the output-side end face of the light emitting medium, the light emitting medium is made of low phonon glass. In terms of materials, it is particularly preferable to use an oxide-based fiber as the output fiber.

In the third, fifth, seventh, and ninth embodiments described above, the partial reflecting mirror that constitutes the resonator 1 is not limited to the illustrated meniscus lens shape, and is a combination of a concave reflecting mirror and a convex lens, or a part of the semiconductor light emitting element end face. It may be replaced with another configuration that realizes a similar function such as forming a reflecting mirror and combining it with a convex lens.

In the fourth, sixth, eighth, and tenth embodiments described above, a combination of an optical thin film or a cleaved end face formed on the end face of a semiconductor light emitting device exemplified as a partial reflector constituting a semiconductor laser resonator and a lens-shaped input end face In addition, other combinations that realize similar functions, such as a combination of a concave reflecting mirror, a convex lens, and an input end face with a broadband non-reflective coating, and a combination of a meniscus-shaped reflecting mirror and an input end face with a broadband non-reflective coating It may be replaced with a configuration.

In the first to tenth embodiments described above, the reflective element (corresponding to the first reflective element) that highly reflects both the excitation light wavelength from the semiconductor light emitting element and the light emission wavelength from the light emitting medium as a shared mirror, A dielectric multilayer mirror, metal or alloy mirror, distributed diffractive mirror (so-called DBR), or distributed feedback structure (so-called DFB) can be selected as appropriate. These reflective elements can be formed by directly forming a film on the end face of the semiconductor light emitting element or by directly forming the reflective element when manufacturing the semiconductor light emitting element. The use of a semiconductor light emitting device in which a film is formed directly on the end face of the semiconductor light emitting device or a reflective element is directly used is suitable for cost reduction and mass production, and is particularly preferable. Among these, DBR and DFB are particularly preferable from the viewpoint of simplification of the manufacturing process and optical position adjustment because they can be formed at the same time when the semiconductor light emitting device is manufactured.

In the above first to tenth embodiments, the semiconductor light emitting device used is a waveguide having a normal mesa structure in which an active layer is sandwiched between cladding layers, a quantum well structure, and a transparent window structure in the vicinity of the output end face. Any material can be used as long as it has a structure that functions as a semiconductor optical waveguide having an optical amplification function, such as a structure, and is transparent to the wavelength of the laser light oscillated by the second optical resonator. For example, if the active layer has a strained quantum well structure of InGaN-based material and the cladding layer uses n-type or p-type GaN-based material, it is transparent at wavelengths longer than the wavelength of the excitation light generated by this device. And can be transmitted with low loss. As an example in this case, a mesa structure strained quantum well InGaN laser having an oscillation wavelength (excitation light wavelength) of 440 nm is used as a semiconductor light-emitting device, and a Pr-doped fluoride glass fiber is used as a light-emitting medium. The laser oscillation wavelength oscillated by the resonator can be selected from a 490 nm band, a 520 nm band, a 602 nm band, a 635 nm band, a 715 nm band, a 900 nm band, and the like, and the InGaN active layer or the cladding layer closest to the active layer can be used for any wavelength. Because it transmits light with low loss, it can be easily output to the outside.

When a GaN-based semiconductor laser is used as the semiconductor light emitting device, the active ions added to the light emitting medium that emits fluorescence by absorbing the emitted excitation light depends on the specific wavelength of the excitation light. However, Pr ³⁺ , Nd ³⁺ , Sm ³⁺ , Eu ³⁺ , Tb ³⁺ , Dy ³⁺ , Gd ³⁺ , Ho ³⁺ , Er ³ can be excited in the wavelength range of 350 nm to 490 nm. ⁺ , Tm ³⁺ , Sm ²⁺ , Eu ²⁺ and Yb ²⁺ . These rare earths emit fluorescent light in the visible or near-infrared wavelength region where the GaN-based semiconductor laser material is highly transparent, and are therefore suitable as added ions to the light-emitting medium suitable for the resonator structure of the present invention. . The material of the light-emitting medium to which these ions are added is a low phonon optical material that can obtain high light emission efficiency for rare-earth fluorescence in the visible to near-infrared region, and the emission wavelength of the GaN-based semiconductor laser is ultraviolet to green. It is preferably transparent in the wavelength band. Specifically, it is selected from halide glass, halide crystal, halide oxide glass, halide oxide crystal, or oxide glass or organic-inorganic hybrid material in which fine particles of these materials added with active ions such as rare earth are dispersed. Can do. Among these, fluoride glass, fluoride crystal, fluorine oxide glass, and fluorine oxide crystal are most preferable because they can easily produce a light emitting medium and have practical durability.

A combination of active ions added to the semiconductor light emitting element and the light emitting medium can be selected as appropriate.

Furthermore, there are various types of fluoride glass used in the present invention, but ZrF ₄ (HfF ₄ ) -BaF ₂ -LnF ₃ (selected from Ln: Sc, Y and rare earth elements) -AlF ₃ -NaF. Composition system [Zr—F system], AlF ₃ —LnF ₃ (selected from Ln: Sc, Y and rare earth elements) —MgF ₂ (ZnF ₂ ) —CaF ₂ —SrF ₂ —BaF ₂ [Al—F system] AlF ₃ —ZrF ₄ (HfF ₄ ) —LnF ₃ (Ln: selected from Sc, Y and rare earth elements) —MgF ₂ (ZnF ₂ ) —CaF ₂ —SrF ₂ —BaF ₂ [Al—Zr—F system InF ₃ (GaF ₃ ) -LnF ₃ (Ln: selected from Sc, Y and rare earth elements) -MgF ₂ (ZnF ₂ ) —CaF ₂ —SrF ₂ —BaF ₂ [In—F system] Suitable for stability .

There are various types of fluorine oxide glass, but from the viewpoint of phonon energy, a material having an oxygen / fluorine atomic ratio of 1 or less is preferable because of its low loss in terms of ultraviolet absorption.

There are various types of fluoride crystals, including Li (Y, Lu) F ₄ , Li (Ca, Sr) (Al, Ga) F ₆ , (Ba, Sr) (Y, Lu) ₂ F ₈ , Ba (Mg, Zn) F ₄ , (Ca, Sr) (Al, Ga) F ₅ , Na ₂ (Mg, Zn) AlF _{7 and the} like are suitable.

Also, active center-added material dispersed oxide glass or active center-added material dispersed in the above glass or crystal by adding a material that becomes an active center into fine particles and dispersed in oxide glass, organic material, or organic-inorganic hybrid material The organic-inorganic hybrid material can be designed relatively freely with respect to the optical, mechanical, chemical, and thermal properties of the matrix material, and may be supplied at a low cost. In particular, an active center-added material-dispersed organic-inorganic hybrid material dispersed in an organic material or an organic-inorganic hybrid material has a high degree of freedom in molding shape and is advantageous in terms of price. The particle diameter of the material to be dispersed is preferably ¼ or less of the shortest wavelength that is actually used in the wavelength band of the generated fluorescence.

For the purpose of reducing the loss of the resonator constituting the present invention, it is preferable to form a low reflection film on the reflective element, the semiconductor light emitting element, the light emitting medium, and other optical components as necessary.

In addition, when the output oscillation wavelength and the excitation light wavelength are close to each other, a Fresnel lens or a diffractive optical element may be formed directly on the light emitting medium side end face of the semiconductor light emitting element for the purpose of increasing the optical coupling efficiency. preferable. In this case, the vicinity of the end surface on the light emitting medium side of the semiconductor light emitting element is particularly preferably a so-called window region without current injection.

For the lenses used in the present invention, it is preferable to use an achromatic lens whose focal length is the same between the excitation light wavelength and the output oscillation wavelength, or an aspheric lens operating at both wavelengths.

In particular, the lens-shaped input ends exemplified in the above fourth, sixth, eighth, and tenth embodiments have different fiber dispersion values at the pumping light wavelength and the laser light wavelength. Since dispersion may occur, fluorides such as NaAlF ₄ , CaF ₂ , SrF ₂ and BaF ₂ are formed into appropriate thicknesses as dispersion compensation materials having dispersion values different from the fiber material dispersion characteristics. It is particularly preferable to adjust. When dispersion compensation is performed with a dispersion compensation film by this method, the broadband antireflection coating should be formed both above and below the dispersion compensation film (the interface between the dispersion compensation film and the air and the interface between the dispersion compensation film and the lens-shaped end face). Is particularly preferred.

As the reflecting element used in the present invention, a mirror in which a dielectric multilayer film or a metal film is deposited or formed on a glass or transparent crystallized glass substrate can be used. For a mirror that does not transmit light, a metal mirror or a mirror in which a dielectric multilayer film or a metal film is deposited or formed on a substrate made of metal or ceramics can be used.

Further, in the above first to tenth embodiments, the laser light is output from the reflection element of the second optical resonator that is not shared, but the reflection shared by the first optical resonator and the second optical resonator. By adjusting the reflectance of the element with respect to the output oscillation wavelength, the laser light can be output to the outside also from the shared reflecting element. In addition, when the light emitting medium emits fluorescence of a plurality of wavelength bands, it is shared with the reflective element of the second optical resonator that is not shared by adjusting the wavelength dependency of the reflective element shared with the second optical resonator. It is possible to output laser beams having different wavelengths from the reflecting element.

When the emission wavelength band of the luminescent medium is wide, insert a dispersion element such as a prism or a diffraction grating as a laser oscillation wavelength selection element in the resonator, or insert a wavelength plate with a continuously variable wavelength, or change the wavelength. A tunable laser can be obtained by a method such as inserting a simple etalon.

Further, when the emission wavelength band of the light emitting medium is wide, short pulse laser oscillation with a pulse width of 100 ns or less is possible by inserting a saturable absorbing element and a dispersion compensation optical system into the resonator. For example, when a ZBLAN fiber doped with Pr ³⁺ is used as a light emitting medium and excited by a GaN-based semiconductor laser, for example, the above-described first or second embodiment is used for a resonator, and a saturable absorber and dispersion compensation optics are used. A compact and highly efficient visible light band short pulse laser can be realized by inserting the system between the light emitting medium and the output mirror to form a solid-state laser resonator. As a saturable absorber, a material that exhibits appropriate absorption saturation characteristics in a visible broadband such as a dye-added film, carbon nanotube, graphene, ZnO thin film, In ₂ O ₃ —SnO ₂ thin film (ITO thin film), TiN thin film should be used. Can do. These materials can be used as a fiber type device by forming a film on the end face of the fiber with the aid of a member such as a ferrule.

Hereinafter, specific examples using the present invention will be disclosed.

This example is an example of the first embodiment shown in FIG. In FIG. 1, display of the power source and the control device to the semiconductor light emitting element 4 is omitted.

The semiconductor light emitting device 4 used in this example is a mesa structure chip having an emission center wavelength of 442 nm using an InGaN multiple quantum well (MQW) active layer as a light emitting layer, and the GaN substrate surface is bonded to an AlN heat sink. The active layer has a thickness of 0.8 μm, a light emission width of 7 μm, an element length of 1 mm, and a current non-injection window region of 0.05 mm in length at both ends of the element.

The radiant light emitted from the semiconductor light emitting element 4 (in the direction toward the reflecting element 7 in FIG. 1) has a high transmittance of 15% reflectance at the emission center wavelength of 442 nm and 0.5% reflectance at the wavelength of 520 nm. Is reflected in the active layer of the semiconductor light emitting element 4 and is emitted backward (in the direction toward the reflective element 6 in FIG. 1). The light having a wavelength of 442 nm emitted backward is reflected and bent by the reflecting element 6, passes through the reflecting element 9, and reaches the reflecting element 8. The

reflective elements

6 and 8 are high-reflectivity mirrors having a reflectivity of 99% and 99.5%, respectively, at a wavelength of 442 nm. The reflecting element 9 has a high reflectance of 0.5% at a wavelength of 442 nm and 99.5% at a laser wavelength of 520 nm on the incident surface of the emitted light from the semiconductor light emitting element 4 reflected and bent by the reflecting element 6. A dichroic optical film is formed, and an antireflection film having a wavelength of 442 nm and a reflectance of 0.3% is formed on the surface opposite to the incident surface, and is a transparent mirror at a wavelength of 442 nm. Further, the reflecting element 6 is a high-reflectance broadband high-reflection mirror having a reflectance of 99.5% even at a wavelength of 520 nm. The semiconductor laser resonator 1 including the reflective element 7 -the semiconductor light emitting element 4 -the reflective element 6 -the reflective element 8 is a semiconductor laser resonator, and emits excitation light having a wavelength of 442 nm from the reflective element 7 toward the light emitting medium 5. To do.

Note that antireflection films having a reflectance of 0.3 to 1% in the wavelength range of 400 nm to 700 nm are formed on both end faces of the semiconductor light emitting element 4 on the reflecting element 6 side and the 7 side. In this embodiment, the reflecting element 7 is a plane mirror, the mirror thickness is 0.5 mm, and the distance between the semiconductor light emitting element 4 and the reflecting element 7 is about 0.1 mm. The reflecting element 6 is a parabolic reflector having a focal length of 4 mm, and is adjusted so as to focus on the surfaces of the reflecting element 7 and the reflecting element 9. The distance between the reflecting element 7 and the reflecting element 6 is about 6 mm. The distance of the reflective element 6 was about 12 mm. The reflective element 9 uses a flat quartz glass substrate having a thickness of 1 mm, and the reflective element 8 is a spherical mirror having a focal length of 4.5 mm. The distance between the surface of the reflective element 9 and the reflective element 8 was about 9.5 mm.

For the luminescent medium 5, a LiYF ₄ rod having a length of 4 mm and a diameter of 2 mm to which Pr ³⁺ is added at 1 atomic mass% is prepared, and the reflectance is 0.3 to 0.5% in the wavelength range of 400 nm to 700 nm on both end faces. An antireflection film is formed. Although omitted in FIG. 1, NA = 0.6, a focal length of 2 mm, and a design wavelength of 500 nm are collected between the reflective element 7 and the light emitting medium 5 so that the focal lengths are substantially the same at wavelengths of 440 nm and 520 nm. The achromatic lens for light A ₁ is inserted about 2.5 mm from the surface of the reflecting element 7, and not only the excitation light is condensed and irradiated onto the light emitting medium 5, but also the laser light with a wavelength of 520 nm is emitted from the semiconductor light emitting element. 4 is adjusted so as to pass almost the same optical path as the excitation light in 4. The condensed excitation light is absorbed by the light emitting medium 5 by about 90%. The distance between the reflective element 10 and the reflective element 7 was about 12.5 mm.

Fluorescence having a wavelength of 520 nm emitted from the light emitting medium 5 toward the reflecting element 10 is folded back by the reflecting element 10 that is a partially reflecting parabolic mirror having a focal length of 4 mm and a reflectance of 98% at a wavelength of 520 nm. The light is reflected by the reflecting element 6 and transmitted through the semiconductor light emitting element 4, and returns to the light emitting medium 5 through the reflecting element 7 and the condensing achromatic lens A ₁ . The path opposite to this path functions in the same manner with respect to the fluorescence emitted from the light emitting medium 5 toward the reflecting element 7 to form a feedback optical circuit to the light emitting medium 5. The feedback optical system for the radiation of the light emitting medium 5 to the fluorescent reflecting element 10 side and the reflecting element 7 side constitutes a ring laser resonator 2. A laser beam having a center wavelength of 520 nm is transmitted through the reflecting element 10 which is a partial reflecting mirror and output 3. Although the laser beam output 3 is represented by one in FIG. 1, two clockwise and counterclockwise laser beams are output simultaneously.

In this configuration, although it is necessary to pay attention to the angle of the reflecting element 6 that is a shared mirror, the reflecting element 6, the reflecting element 8, and the reflecting element 7 are adjusted so that the output of the semiconductor laser resonator 1 is maximized. At this time, the pumping light power radiated from the semiconductor laser resonator 1 was 160 mW at the maximum. After adjusting the semiconductor laser resonator ₁ , the position of the condensing achromatic lens A ₁ is adjusted to condense and irradiate the light emitting medium 5 with excitation light, and the condensing achromatic lens A ₁ , the light emitting medium 5, and the reflective element By adjusting 10 and optimizing the ring laser resonator 2, laser oscillation was easily obtained. At this time, it took 5 minutes to adjust the ring laser resonator 2 until the laser oscillation was started. Further, the ring laser output at this time was 10 mW in total.

Comparative Example 1

This example will be described with reference to FIG. In FIG. 11, the semiconductor light emitting device 1104 is used as an excitation light source, and a light emitting medium 1105 that absorbs the excitation light and emits light having a wavelength different from that of the excitation light is provided, and the light of the semiconductor optical device 1104 that generates the excitation light is enhanced. As a resonator for performing the above, a semiconductor laser resonator 1101 including a reflection element 1121 and a reflection element 1120 and a resonator for enhancing light emission from the light emitting medium 1105 are used as a reflection element 1123, a reflection element 1124, and a reflection element 1107. And a condensing lens 1122 for condensing the excitation light emitted from the semiconductor laser resonator 1101 on the light emitting medium 1105. The semiconductor light emitting device 1104 and the light emitting material 1105 used in this comparative example are the same as those in Example 1. Further, the display of the power supply and control device to the semiconductor light emitting element 1104 is omitted.

The radiation from the semiconductor light emitting element 1104 to the reflecting element 1120 side is reflected by the reflecting element 1120 which is a 0.5 mm thick flat reflecting mirror on which an optical reflecting film having a light emission center wavelength of 442 nm and a reflectance of 15% is formed. Then, it is amplified in the active layer of the semiconductor light emitting device 1104 and emitted to the reflective element 1121 side. The radiation toward the reflecting element 1121 is folded back by the reflecting element 1121 which is a high-reflectance spherical mirror having a focal length of 4 mm at a wavelength of 442 nm, and forms a semiconductor laser resonator 1101. The distance between the reflective element 1121 and the reflective element 1120 was about 9 mm, and the distance between the semiconductor light emitting element 1104 and the reflective element 1120 was about 0.1 mm. A part of the light amplified in the semiconductor laser resonator 1101 is emitted from the reflection element 1120 as excitation light of the light emitting medium 1105.

The emitted excitation light is reflected by a condensing lens 1122 and is a reflecting element that is a parabolic mirror having a reflectance of 0.5% at the excitation light wavelength, a reflectance of 99.5% at the laser light wavelength of 520 nm, and a focal length of 6.4 mm The light emitting medium 1105 is condensed and irradiated through 1123. The focal length of the condenser lens 1122 was 1.8 mm, the distance from the reflective element 1120 was about 2 mm, and the distance between the condenser lens 1122 and the reflective element 1123 was about 1 mm.

The fluorescence having a wavelength of 520 nm emitted from the light emitting medium 1105 to the reflection element 1107 side is folded by the reflection element 1107 which is a partially reflecting parabolic mirror having a focal length of 4 mm and a wavelength of 520 nm and a reflectance of 90%. The light is reflected by 99.5% of the reflective element 1124 and the reflective element 1123 and returned to the light emitting medium 1105.

The path opposite to this path functions in the same manner with respect to the fluorescence emitted from the light emitting medium 1105 to the reflecting element 1123, and forms a feedback optical circuit to the light emitting medium 1105. The feedback optical system for the radiation of the light emitting medium 1105 to the fluorescent reflecting element 1107 side and the reflecting element 1123 side constitutes a ring laser resonator (solid laser resonator 1102).

A laser beam having a center wavelength of 520 nm is transmitted through the reflecting element 1107, which is a partial reflecting mirror, and output 1103. Although the laser beam output 1103 is expressed as one in FIG. 11, two clockwise and counterclockwise laser beams are output simultaneously. The distance between the reflecting element 1123 and the reflecting element 1107 was about 20 mm, and the distance between the reflecting element 1123 and the reflecting element 1124 and between the reflecting element 1107 and the reflecting element 1124 was about 12 mm.

In such a general ring laser configuration, since there is no relationship between the semiconductor laser resonator 1101 and the ring laser resonator (solid laser resonator 1102), the semiconductor laser resonator 1101 and the solid laser resonator 1102 In addition to setting the relative distance and the relative angle, an optimum arrangement cannot be obtained unless all the optical elements of the solid-state laser resonator 1102 are adjusted by trial and error, which is very troublesome.

In this experimental arrangement, the maximum radiation power from the semiconductor laser resonator 1101 was 180 mW. After optimizing the semiconductor laser resonator 1101, the time required from the adjustment of the solid-state laser resonator 1102 to the start of laser oscillation was 45 minutes. Further, the ring laser output at this time was 4 mW in total.

This example is an example of the second embodiment shown in FIG. In FIG. 2, display of the power source and the control device to the semiconductor light emitting element 204 is omitted.

The semiconductor light emitting device 204 used in this example is a mesa structure chip having an emission center wavelength of 440 nm using an InGaN multiple quantum well (MQW) active layer as a light emitting layer, and the GaN substrate surface is bonded to an AlN heat sink. The active layer has a thickness of 0.8 μm, a light emission width of 7 μm, an element length of 1 mm, and a current non-injection window region of 0.05 mm in length at both ends of the element.

The forward radiation (in the direction toward the reflecting element 207 in FIG. 2) from the semiconductor light emitting element 204 forms a dichroic optical film having a high transmittance of 15% reflectance at a wavelength of 440 nm and 0.3% reflectance at a wavelength of 520 nm. The light is reflected by the coated reflective element 207, amplified in the active layer of the semiconductor light emitting element 204, and emitted backward (in the direction toward the reflective element 206 in FIG. 2). The light having a wavelength of 440 nm emitted backward is reflected and reflected by the reflecting element 206 which is a broadband high-reflecting mirror, and is amplified again in the semiconductor light emitting device 204. The optical resonator composed of the reflecting element 207, the semiconductor light emitting element 204, and the reflecting element 206 is the semiconductor laser resonator 201, and emits excitation light having a wavelength of 440 nm from the reflecting element 207 to the light emitting medium 205 side.

Note that antireflection films having a reflectance of 0.5 to 1% in the wavelength range of 400 nm to 700 nm are formed on both end surfaces of the semiconductor light emitting element 204 on the reflective element 206 side and the reflective element 207 side. In this embodiment, the reflecting element 207 is a plane mirror having a thickness of 0.5 mm, and the distance between the semiconductor light emitting element 204 and the reflecting element 207 is about 0.1 mm. The reflective element 206, which is a spherical reflector with a focal length of 3.5 mm, was adjusted so as to be focused near the end face of the semiconductor light emitting material 204. The distance between the reflective element 207 and the reflective element 206 was about 8 mm.

As the luminescent medium 205, a LiYF ₄ rod having a length of 4 mm and a diameter of 2 mm to which Pr ³⁺ is added at 1 atomic mass% is prepared, and the reflectance is 0.5 to 1% in a wavelength range of 400 nm to 700 nm on both end faces. An antireflection film is formed. Although omitted in FIG. 2, NA = 0.6, focal length 2.8 mm, and design wavelength 500 nm so that the focal lengths are substantially the same at wavelengths of 440 nm and 520 nm between the reflective element 207 and the light emitting medium 205. The condensing achromatic lens A ₂ is inserted about 4 mm from the surface of the reflecting element 207, and not only the excitation light having a wavelength of 440 nm is condensed and irradiated onto the light emitting medium 205, but also the laser light having a wavelength of 520 nm is emitted. It is adjusted so as to pass almost the same optical path as the excitation light in the semiconductor light emitting device 204. The condensed excitation light is absorbed by the light emitting medium 205 by about 90%.

The fluorescence having a wavelength of 520 nm emitted from the light emitting medium 205 to the reflecting element 210 is folded by the reflecting element 210 which is a partially reflecting flat mirror having a reflectance of 95% at a wavelength of 520 nm, and is amplified in the light emitting medium 205. The distance between the reflective element 210 and the light emitting medium 205 was about 0.1 mm, and the distance between the condensing achromatic lens A ₂ and the reflective element 207 was about 9.5 mm. The reflecting element 206, the reflecting element 207, the condenser lens A _{2, the} light emitting medium 205, and the reflecting element 210 constitute a Fabry-Perot type solid-state laser resonator 202. A laser beam having a center wavelength of 520 nm is transmitted through the reflecting element 210, which is a partial reflecting mirror, and output 203.

In this configuration, the reflecting element 206 and the reflecting element 207 were first adjusted so that the output of the semiconductor laser resonator 201 was maximized. At this time, the pumping light power radiated from the semiconductor laser resonator 201 was 220 mW at the maximum. After adjusting the semiconductor laser resonator 201, the position of the condensing achromatic lens A ₂ is adjusted to condense and irradiate the light emitting medium 205 with excitation light, and the condensing achromatic lens A ₂ , the light emitting medium 205, and the reflective element By adjusting 210 and optimizing the solid-state laser resonator 202, laser oscillation was easily obtained. At this time, the time required for adjusting the solid-state laser resonator 202 until the laser oscillation was started was only 3 minutes. Moreover, the solid-state laser output at this time was 17 mW.

Comparative Example 2

This example will be described with reference to FIG. In FIG. 12, the display of the power source and the control device to the semiconductor light emitting element 1204 is omitted.

The semiconductor light emitting device 1204 and the light emitting medium 1205 used in this comparative example are the same as those in Example 2.

The radiation from the semiconductor light emitting element 1204 toward the reflective element 1220 is reflected by the reflective element 1220 having an optical reflective film having a wavelength of 440 nm and a reflectivity of 15%, and is amplified in the active layer of the semiconductor light emitting element 1204 to be reflected. Radiated to the 1221 side. The light having a wavelength of 440 nm emitted to the reflection element 1221 side is folded back by the reflection element 1221 to constitute the semiconductor laser resonator 1201. The semiconductor laser resonator 1201 emits excitation light having a wavelength of 440 nm from the reflective element 1220.

In this comparative example, the reflective element 1220 was a plane mirror having a thickness of 0.5 mm, and the distance between the semiconductor light emitting element 1204 and the reflective element 1220 was about 0.1 mm. The reflective element 1221 which is a spherical reflector having a focal length of 3.5 mm was adjusted so as to be focused near the end face of the semiconductor light emitting material 1204. The distance between the reflective element 1221 and the reflective element 1220 is about 8 mm.

The emitted excitation light is transmitted to the luminescent medium 1205 by the condenser lens 1222 through the reflective element 1223 of a spherical reflector having a focal length of 5 mm, which has a reflectance of 0.5% at a wavelength of 440 nm and a reflectance of 99% at a wavelength of 520 nm. Focused irradiation.

The distance between the condenser lens 1222 having a focal length of 1.8 mm and the reflecting element 1220 was about 2.2 mm. The distance between the condenser lens 1222 and the reflective element 1223 was about 1 mm, and the distance between the reflective element 1223 and the reflective element 1207 was about 11 mm.

Fluorescence having a wavelength of 520 nm emitted from the light emitting medium 1205 to the reflecting element 1207 side is folded back by a reflecting element 1207 which is a partially reflecting flat mirror having a reflectance of 90% at a wavelength of 520 nm, and reflected by a reflecting element 1223 that reflects 99% at a wavelength of 520 nm. The light is reflected and returned to the light emitting medium 1205. The reflecting element 1223-the light emitting medium 1205 and the reflecting element 1207 constitute a Fabry-Perot type solid state laser resonator 1202. A laser beam having a center wavelength of 520 nm is transmitted through a reflecting element 1207 that is a partial reflecting mirror and output 1203.

In such a general Fabry-Perot type laser configuration, since there is no relationship between the semiconductor laser resonator 1201 and the solid-state laser resonator 1202, the relative distance between the semiconductor laser resonator 1201 and the solid-state laser resonator 1202, In addition to setting the relative angle, an optimal arrangement cannot be obtained unless all the optical elements of the solid-state laser resonator 1202 are adjusted by trial and error, which is very troublesome.

In this experimental arrangement, the maximum radiation power from the semiconductor laser resonator 1201 was 220 mW. After optimizing the semiconductor laser resonator 1201, the time required from the adjustment of the solid-state laser resonator 1202 to the start of laser oscillation was 15 minutes. Moreover, the solid-state laser output at this time was 12 mW.

This example is an example of the third embodiment shown in FIG. In FIG. 3, display of the power source and the control device to the semiconductor light emitting element 304 is omitted.

The semiconductor light emitting device 304 used in this example is a mesa structure chip having an emission center wavelength of 445 nm using an InGaN multiple quantum well (MQW) active layer as a light emitting layer, and the GaN substrate surface is bonded to an AlN heat sink. The active layer has a thickness of 0.8 μm, a light emission width of 7 μm, an element length of 1 mm, and a current non-injection window region of 0.05 mm in length at both ends of the element.

The radiation from the semiconductor light emitting element 304 to the reflecting element 313 is reflected in the shape of a convex meniscus lens formed with a dichroic optical film having a high transmittance of 15% reflectance at a wavelength of 445 nm and 0.5% reflectance at a wavelength of 521 nm. The light is reflected from the concave surface of the element 313, amplified in the active layer of the semiconductor light emitting element 304, and emitted to the reflective element 306. The light having a wavelength of 445 nm emitted to the reflecting element 306 is reflected by the reflecting element 306, which is a broadband high-reflecting mirror, folded back, and amplified again in the semiconductor light emitting element 304. The optical resonator composed of the reflective element 313 -the semiconductor light emitting element 304 and the reflective element 306 is the semiconductor laser resonator 301, and emits excitation light having a wavelength of 445 nm from the reflective element 313 to the light emitting medium 305 side.

Note that antireflection films having a reflectance of 0.5 to 1% in the wavelength range of 400 nm to 700 nm are formed on both end surfaces of the semiconductor light emitting element 304 on the reflective element 306 side and the reflective element 313 side. In this embodiment, the concave surface of the reflective element 313 is a spherical mirror having a focal length of 2.5 mm, and the distance between the semiconductor light emitting element 304 and the reflective element 313 is about 5 mm. The reflective element 306, which is a spherical reflector with a focal length of 2.5 mm, was adjusted so as to be focused near the end face of the semiconductor light emitting material 304. The distance between the reflective element 313 and the reflective element 306 is about 11 mm.

The reflection element 313 has a convex meniscus lens shape, and an antireflection film having a reflectance of about 0.5% is formed on the convex surface side at both a wavelength of 521 nm and a wavelength of 445 nm. The excitation light radiated from the semiconductor laser resonator 301 is condensed on the excitation side end face 315 of the light emitting medium 305 in the form of a fiber by the reflecting element 313 and coupled to the core of the light emitting medium 305. Conversely, laser light having a wavelength of 521 nm emitted from the excitation side end face 315 of the light emitting medium 305 is substantially coupled to the active layer of the semiconductor light emitting element 304 by the reflecting element 313. An antireflection film having a reflectivity of 0.3 to 0.5% is formed on the excitation-side end surface 315 of the light emitting medium 305 at a wavelength of 521 nm which is a laser light wavelength and a wavelength of 445 nm which is an excitation light wavelength.

The emission medium 305, was used length 10cm and the Pr ³⁺ added 3000 ppm by weight in the core, the core diameter 4 [mu] m, the fluoride fiber having a numerical aperture of 0.22. The core composition of this fiber is 53ZrF ₄ −22BaF ₂ −4.5LnF ₃ −3.5AlF ₃ −17NaF (LnF ₃ = LaF ₃ + YF ₃ + PrF ₃ ) in mol%. The condensed excitation light is absorbed by the light emitting medium 305 by about 90%.

Fluorescence having a wavelength of 521 nm emitted from the end surface opposite to the excitation-side end surface 315 from the light emitting medium 305 is folded back by a reflecting element 314 having a reflectivity of 85% at a wavelength of 521 nm formed on the other fiber end. Amplified in the luminescent medium. The reflective element 306, the reflective element 313, the light emitting medium 305, and the reflective element 314 constitute a Fabry-Perot solid laser resonator 302. Laser light having a center wavelength of 521 nm is output 303 from the reflection element 314 which is a partial reflection mirror.

In this configuration, the reflecting element 306 and the reflecting element 313 were first adjusted so that the output of the semiconductor laser resonator 301 was maximized. At this time, the pumping light power radiated from the semiconductor laser resonator 301 was 200 mW at the maximum. After adjusting the semiconductor laser resonator 301, laser oscillation was easily obtained by adjusting the position of the excitation side end face 315 of the light emitting medium 305 and condensing and irradiating the light emitting medium 305 with excitation light. At this time, the time required for adjustment of the solid-state laser resonator 302 until the start of laser oscillation was only 2 minutes, and the maximum output was 29 mW. Further, when the maximum output wavelength is the center wavelength and the laser line width is defined by a wavelength width that is ½ of the output, it is 4 nm.

This example is an example of the fourth embodiment shown in FIG. In FIG. 4, display of the power source and the control device to the semiconductor light emitting element 404 is omitted.

The semiconductor light emitting element 404 used in this example is a mesa structure chip having an emission center wavelength of 442 nm using an InGaN multiple quantum well (MQW) active layer as a light emitting layer, and the GaN substrate surface is bonded to an AlN heat sink. The active layer has a thickness of 0.8 μm, a light emission width of 7 μm, an element length of 1 mm, and a current non-injection window region of 0.05 mm in length at both ends of the element.

The radiation from the semiconductor light emitting element 404 toward the fiber-shaped light emitting medium 405 is directly formed on the semiconductor light emitting element having a high transmittance of 15% reflectance at a wavelength of 442 nm and 0.5% reflectance at a wavelength of 520 nm. The dichroic optical film is reflected by the reflecting element 413, amplified in the active layer of the semiconductor light emitting element 404, and emitted to the reflecting element 406 side. The light having a wavelength of 442 nm emitted toward the reflective element 406 is reflected by the reflective element 406, which is a broadband high-reflection spherical mirror having a focal length of 2.5 mm, and is amplified again in the semiconductor light emitting element 404. The distance between the reflective element 406 and the semiconductor light emitting element 404 was about 5 mm. The optical resonator composed of the reflective element 413 -the semiconductor light emitting element 404 -the reflective element 406 is the semiconductor laser resonator 401, and emits excitation light having a wavelength of 442 nm from the reflective element 413 to the light emitting medium 405 side.

Note that an antireflection film having a reflectance of 0.5 to 1% in the wavelength range of 400 nm to 700 nm is formed on the end face of the semiconductor light emitting element 404 on the reflective element 406 side.

The light-emitting medium 405 includes a cylindrical lens-shaped lensed fiber 416 having a curvature radius of 3 μm at one end, and a reflecting element 414 having a reflectance of 50% at a wavelength of 520 nm at one end. The pumping light emitted from the semiconductor laser resonator 401 is incident on the light emitting medium 405 by correcting the divergence angle in the vertical direction by the lensed fiber 416 installed in the vicinity of the pumping light emitting region, and enters the core of the fiber. Combined. Conversely, laser light having a wavelength of 520 nm emitted from the lensed fiber 416 is substantially coupled to the active layer of the semiconductor light emitting element 404.

The surface of the lensed fiber 416 is formed with a dispersion compensation film made of CaF ₂ in order to suppress focal position fluctuations due to chromatic aberration at wavelengths of 442 nm and 520 nm, and further has a laser light wavelength of 520 nm and an excitation light wavelength. An antireflection film having a reflectance of about 0.5% at a wavelength of 442 nm is formed.

The emission medium 405, was used length 20cm and the Pr ³⁺ added 3000 ppm by weight in the core, the core diameter 4 [mu] m, the fluoride fiber having a numerical aperture of 0.22. The core composition of this fiber is 30AlF ₃ -10ZrF ₄ -11BaF ₂ -13SrF ₂ -20CaF ₂ -3MgF ₂ -4NaF-9LnF ₃ (LnF ₃ = YF ₃ + PrF ₃ ) in mol%. The condensed excitation light is absorbed by the light emitting medium 405 by about 95%.

Fluorescence having a wavelength of 520 nm emitted from the light emitting medium 405 toward the reflecting element 414 is folded by the formed reflecting element 414 having a reflectivity of 50% and amplified in the light emitting medium 405. The reflective element 406, the reflective element 413, the lensed fiber 416, the light emitting medium 405, and the reflective element 414 constitute a Fabry-Perot type solid-state laser resonator 402. A laser beam having a center wavelength of 520 nm is output 403 from a reflection element 414 that is a partial reflection mirror.

In this configuration, first, the reflection element 406 was adjusted so that the output of the semiconductor laser resonator 401 was maximized. At this time, the power of pumping light emitted from the semiconductor laser resonator 401 was 250 mW at the maximum. After adjusting the semiconductor laser resonator 401, it is easy to measure the output 403 of the laser light while condensing and irradiating the light emitting medium 405 with excitation light, and adjusting the position, angle, and distance from the semiconductor light emitting element of the lensed fiber 416. In addition to laser oscillation, the power can be easily optimized. At this time, the time required for adjusting the solid-state laser resonator 402 until the start of laser oscillation was only 1 minute, and power optimization was achieved in 3 minutes, and a maximum output of 34 mW was obtained. Further, when the maximum output wavelength is the center wavelength and the laser line width is defined by a wavelength width that is ½ of the output, it is 4 nm.

This example is an example of the fifth embodiment shown in FIG. In FIG. 5, display of the power source and the control device to the semiconductor light emitting element 504 is omitted.

The semiconductor laser resonator 501 used in the present example is the same as that in the third example. The light emitting medium 505 is also a fiber having the same parameters as in Example 3.

The excitation light having a wavelength of 445 nm emitted from the semiconductor laser resonator 501 is condensed on the excitation side end surface 515 of the light emitting medium 505 in the form of a fiber by the reflecting element 513 and coupled to the core of the light emitting medium 505. Conversely, laser light having a wavelength of 521 nm emitted from the excitation side end face 515 is substantially coupled to the active layer of the semiconductor light emitting element 504 by the reflecting element 513. The excitation side end face 515 is formed with an antireflection film having a reflectance of about 0.5% at a wavelength of 521 nm which is a laser light wavelength and a wavelength of 445 nm which is an excitation light wavelength.

In the light emitting medium 505, an output fiber 517, which is a quartz fiber, is fusion-spliced to a short surface opposite to the excitation side end face 515 via a reflection element 514 having a reflectance of 40% at a wavelength of 521 nm. Fluorescence having a wavelength of 521 nm emitted from the light emitting medium 505 in the direction of the reflecting element 514 is folded by the reflecting element 514 and amplified in the light emitting medium 505. The reflecting element 506 -the reflecting element 513 -the light emitting medium 505 -the reflecting element 514 constitutes a Fabry-Perot type solid state laser resonator 502.

The reflection element 514 is formed on the end face of the output fiber 517 made of a quartz fiber having NA = 0.2 and a core diameter of 4 μm, and then fused and connected to the light emitting medium 505. The laser beam having a wavelength of 521 nm output from the reflecting element 514 passes through the output fiber 517 and is output 503 from the end face on the opposite side.

In this configuration, first, the reflective element 506 and the reflective element 513 were adjusted so that the output of the semiconductor laser resonator 501 was maximized. At this time, the radiation pumping light power from the semiconductor laser resonator 501 was 200 mW at the maximum. After adjusting the semiconductor laser resonator 501, laser oscillation can be easily obtained simply by adjusting the position of the excitation side end face 515 and condensing and irradiating the light emitting medium 505 with excitation light. At this time, the time required for adjustment of the solid state laser resonator 502 until the start of laser oscillation was only 2 minutes, and the maximum output was 20 mW.

This example is an example of the sixth embodiment shown in FIG. In FIG. 6, the display of the power source and the control device to the semiconductor light emitting element 604 is omitted.

The semiconductor light emitting device 604 used in this example is the same as that in Example 4. The light emitting medium 605 was also a fiber having the same parameters as in Example 4.

The radiation from the semiconductor light emitting element 604 toward the input fiber 618 is a dichroic film formed directly on the semiconductor light emitting element that has a high transmittance of 15% reflectance at a wavelength of 442 nm and 0.3% reflectance at a wavelength of 520 nm. The light is reflected by the reflective element 613 that is an optical film, amplified in the active layer of the semiconductor light emitting element 604, and emitted toward the reflective element 606 side. Light having a wavelength of 442 nm emitted toward the reflective element 606 is reflected by the reflective element 606, which is a broadband high-reflection spherical mirror having a focal length of 2.5 mm, and is amplified again in the semiconductor light emitting device 604. The semiconductor laser resonator 601 including the reflective element 613 -the semiconductor light emitting element 604 -the reflective element 606 emits excitation light having a wavelength of 442 nm forward from the reflective element 613.

Note that an antireflection film having a reflectance of about 0.5% in the wavelength range of 400 nm to 700 nm is formed on the end face of the semiconductor light emitting element 604 on the reflective element 606 side.

The light emitting medium 605 is fused with an input fiber 618 which is a quartz fiber having a lens fiber 616 having a compound cylindrical lens shape having a curvature radius of 3 μm (longitudinal correction) and a curvature radius of 7 μm (lateral correction), and a fusion point 619. Incoming connection. The parameters of the quartz fiber used for the input fiber 618 are NA = 0.2 and a core diameter of 4 μm.

The surface of the lensed fiber 616 is formed with a dispersion compensation film made of CaF ₂ and BaF ₂ in order to suppress focal position fluctuations due to chromatic aberration at wavelengths of 442 nm and 520 nm, and further, a laser beam wavelength of 520 nm and excitation light. An antireflection film having a reflectance in the range of 0.5 to 1% at a wavelength of 442 nm is formed.

The pumping light emitted from the semiconductor laser resonator 601 is incident on the light emitting medium 605 with the divergence angle corrected by the lensed fiber 616 installed in the vicinity of the pumping light emission region, and is coupled to the core of the fiber. Conversely, laser light having a wavelength of 520 nm emitted from the lensed fiber 616 is substantially coupled to the active layer of the semiconductor light emitting device 604.

Fluorescence with a wavelength of 520 nm emitted from the light emitting medium 605 to the input fiber 618 side is folded back by a reflecting element 614 having a reflectivity of 50% at a wavelength of 520 nm formed on the fiber end on the output 603 side. Amplified within. The reflective element 606, the reflective element 613, the lensed fiber 616, the light emitting medium 605, and the reflective element 614 constitute a Fabry-Perot type solid state laser resonator 602. A laser beam having a center wavelength of 520 nm is output 603 from a reflection element 614 that is a partial reflection mirror.

In this configuration, the reflective element 606 was first adjusted so that the output of the semiconductor laser resonator 601 was maximized. At this time, the pumping light power radiated from the semiconductor laser resonator 601 was 250 mW at the maximum. After adjusting the semiconductor laser resonator 601, adjusting the position and angle of the lensed fiber 616 and the distance from the semiconductor light emitting element while measuring the power of the laser output 603 not only provides laser oscillation but also easily Power optimization was possible. At this time, the time required for adjustment of the solid state laser resonator 602 until the start of laser oscillation was only 1 minute, and power optimization was achieved in 3 minutes, and a maximum output of 30 mW was obtained.

This example is an example of the seventh embodiment shown in FIG. In FIG. 7, display of the power source and the control device to the semiconductor light emitting element 704 is omitted.

The semiconductor laser resonator 701 used in the present example is the same as that in the third example. The light emitting medium 705 is also a fiber having the same parameters as in Example 3.

The light emitting medium 705 has an end face opposite to the excitation side of the input fiber 718 which is a quartz fiber provided with an antireflection film having a reflectance of about 0.5% at both wavelengths 521 nm and 445 nm on the end face 715 on the excitation side. The output fiber 717 and the reflection element 714 which are quartz fibers each having a reflection element 714 having a reflectance of 40% at a wavelength of 521 nm on the end surface opposite to the fusion point 719 are fused and connected to each other. It is fusion spliced through.

The parameters of the quartz fiber used for the input fiber 718 and the output fiber 717 are NA = 0.2 and the core diameter is 4 μm.

Excitation light having a wavelength of 445 nm emitted from the semiconductor laser resonator 701 is condensed on the end face 715 of the input fiber 718 by the reflection element 713 and coupled to the core of the light emitting medium 705. Conversely, laser light having a wavelength of 521 nm emitted from the end face 715 is substantially coupled to the active layer of the semiconductor light emitting element 704 by the reflecting element 713.

Fluorescence having a wavelength of 521 nm emitted from the light emitting medium 705 to the output fiber 717 side is folded back by the reflecting element 714 having a reflectance of 40% at the wavelength of 521 nm, and is amplified in the light emitting medium. The reflecting element 706 -the reflecting element 713 -the light emitting medium 705 -the reflecting element 714 constitute a Fabry-Perot type solid state laser resonator 702. The laser light having a wavelength of 521 nm output from the reflective element 714 passes through the output fiber 717 and is output 703 from the end face on the opposite side of the reflective element 714.

In this configuration, first, the reflecting element 706 and the reflecting element 713 were adjusted so that the output of the semiconductor laser resonator 701 was maximized. At this time, the pumping light power radiated from the semiconductor laser resonator 701 was 200 mW at the maximum. After adjusting the semiconductor laser resonator 701, the position of the fiber excitation side end face 715 is adjusted and the light emission medium 705 is simply focused and irradiated with excitation light, so that laser oscillation can be easily obtained. At this time, it took only 2 minutes to adjust the solid state laser resonator 702 until the start of laser oscillation, and the maximum output was 22 mW.

This example is an example of the eighth embodiment shown in FIG. In FIG. 8, display of the power source and the control device to the semiconductor light emitting element 804 is omitted.

The semiconductor light emitting device 804 used in this example is the same as that in Example 4. The light emitting medium 805 was also a fiber having the same parameters as in Example 4.

The radiation from the semiconductor light emitting element 804 toward the input fiber 818 has a high transmittance with a reflectance of 15% at a wavelength of 442 nm and a reflectance of 0.3% at a wavelength of 520 nm, and is formed directly on the semiconductor light emitting element. The light is reflected by the reflective element 813 that is a film, amplified in the active layer of the semiconductor light emitting element 804, and emitted to the reflective element 806 side. Light having a wavelength of 442 nm emitted toward the reflective element 806 is reflected by the reflective element 806, which is a broadband high-reflection spherical mirror having a focal length of 2.5 mm, and is amplified again in the semiconductor light emitting device 804. The semiconductor laser resonator 801 including the reflecting element 813 -the semiconductor light emitting element 804 -the reflecting element 806 emits excitation light having a wavelength of 442 nm from the reflecting element 813 to the input fiber 818 side.

Note that an antireflection film having a reflectance of about 0.5% in the wavelength range of 400 nm to 700 nm is formed on the end face of the semiconductor light emitting element 804 on the reflective element 806 side.

The light emitting medium 805 is fused at a fusion point 819 with an input fiber 818 which is a quartz fiber having a lens fiber 816 having a compound cylindrical lens shape having a curvature radius of 3 μm (longitudinal correction) and a curvature radius of 7 μm (lateral correction). The output fiber 817 is provided with a reflection element 814 on the output fiber 817 side, and the output fiber 817 is fusion-bonded via the reflection element 814. The parameters of the quartz fiber used for the input fiber 818 and the output fiber 817 are NA = 0.2 and a core diameter of 4 μm.

The surface of the lensed fiber 816 is formed with a dispersion compensation film made of CaF ₂ and BaF ₂ in order to suppress focal position fluctuations due to chromatic aberration at wavelengths of 520 nm and 442 nm, and further, a laser beam wavelength of 520 nm and excitation light. An antireflection film having a reflectance of about 0.5% at a wavelength of 442 nm is formed.

Excitation light emitted from the semiconductor laser resonator 801 is incident on the light emitting medium 805 with a divergence angle corrected by a lensed fiber 816 installed in the vicinity of the excitation light emission region, and is coupled to the core of the fiber. Conversely, laser light having a wavelength of 520 nm emitted from the lensed fiber 816 is substantially coupled to the active layer of the semiconductor light emitting element 804.

Fluorescence having a wavelength of 520 nm emitted forward from the light emitting medium 805 is folded back by a reflecting element 814 having a reflectance of 50% at a wavelength of 520 nm, and is amplified in the light emitting medium. The reflecting element 806 -the reflecting element 813 -the lensed fiber 816 -the light emitting medium 805 -the reflecting element 814 constitutes a Fabry-Perot type solid state laser resonator 802. Laser light having a center wavelength of 520 nm propagates through the output fiber 817 through the reflecting element 814 that is a partial reflecting mirror, and is output 803 forward from the fiber end.

In this configuration, first, the reflecting element 806 was adjusted so that the output of the semiconductor laser resonator 801 was maximized. At this time, the maximum pumping light power emitted from the semiconductor laser resonator 801 was 250 mW. After adjusting the semiconductor laser resonator 801, adjusting the position and angle of the lensed fiber 816 and the distance from the semiconductor light emitting element while measuring the power of the laser output 803 not only makes it easy to obtain laser oscillation, but also makes it easy Power optimization was possible. At this time, the time required to adjust the solid state laser resonator 802 until the start of laser oscillation was only 1 minute, and power optimization was achieved in 3 minutes, and a maximum output of 30 mW was obtained.

This example is an example of the ninth embodiment shown in FIG. In FIG. 9, display of the power source and the control device to the semiconductor light emitting element 904 is omitted.

The semiconductor laser resonator 901 used in this example is the same as that in Example 3. The light emitting medium 905 is also a fiber having the same parameters as in the third embodiment.

The light emitting medium 905 is fused to the end surface opposite to the excitation side of the input fiber 918 which is a quartz fiber provided with an antireflection film having a reflectance of about 0.5% at both the wavelength 521 nm and the wavelength 445 nm on the end surface 915. An output fiber which is a quartz fiber having a reflection element 920 made of a fiber Bragg grating (FBG) having a reflectance of 40% at a wavelength of 521 nm on the end surface opposite to the fusion point 921, which is fusion spliced at a point 921. It is fusion-bonded at 917 and a fusion point 919.

The parameters of the quartz fiber used for the input fiber 918 and the output fiber 917 are NA = 0.2 and the core diameter is 4 μm.

Excitation light having a wavelength of 445 nm emitted from the semiconductor laser resonator 901 is condensed on the end face 915 of the input fiber 918 by the reflection element 913 and coupled to the core of the light emitting medium 905. Conversely, laser light having a wavelength of 521 nm emitted from the fiber excitation side end face 915 is substantially coupled to the active layer of the semiconductor light emitting device 904 by the reflecting element 913.

Fluorescence having a wavelength of 521 nm emitted forward from the light emitting medium 905 is folded back by a reflection element 920 that is a fiber diffraction grating having a reflectance of 40% at a wavelength of 521 nm, and is amplified in the light emitting medium 905. The reflecting element 906 -the reflecting element 913 -the light emitting medium 905 -the reflecting element 920 constitutes a Fabry-Perot type solid state laser resonator 902. Laser light having a center wavelength of 521 nm passes through the output fiber 917 and is output 903 from the end face on the opposite side. The bandwidth of the reflection element 920, which is a fiber diffraction grating, was 0.08 nm when the maximum value of the reflectance was the center wavelength and the wavelength width was ½ of the maximum reflectance.

In this configuration, the reflecting element 906 and the reflecting element 913 were first adjusted so that the output of the semiconductor laser resonator 901 was maximized. At this time, the maximum pumping light power emitted from the semiconductor laser resonator 901 was 200 mW. After adjusting the semiconductor laser resonator 901, laser oscillation can be easily obtained by adjusting the position of the end face 915 of the input fiber 918 and condensing and irradiating the light emitting medium 905 with excitation light. At this time, it took only 2 minutes to adjust the solid state laser resonator 902 until the start of laser oscillation, and the maximum output was 24 mW. Further, the line width of the solid-state laser output is 0.1 nm which is very close to the bandwidth of the fiber diffraction grating when the maximum output wavelength is the center wavelength and the wavelength width is ½ of the output.

This example is an example of the tenth embodiment shown in FIG. In FIG. 10, the display of the power source and the control device to the semiconductor light emitting element 1004 is omitted.

The semiconductor light emitting device 1004 used in this example is the same as that in Example 4. The light emitting medium 1005 is also a fiber having the same parameters as in Example 4.

The radiation from the semiconductor light emitting device 1004 toward the input fiber 1018 has a high transmittance of 15% reflectivity at a wavelength of 442 nm and 0.3% reflectivity at a wavelength of 520 nm, and is formed directly on the semiconductor light emitting device 1004. The light is reflected by the reflective element 1013 that is an optical film, amplified in the active layer of the semiconductor light emitting element 1004, and emitted to the reflective element 1006 side. Light having a wavelength of 442 nm emitted toward the reflective element 1006 is reflected by the reflective element 1006, which is a broadband high-reflection spherical mirror having a focal length of 2.5 mm, and is amplified again in the semiconductor light emitting device 1004. The semiconductor laser resonator 1001 including the reflective element 1013 -semiconductor light emitting element 1004 -reflective element 1006 emits excitation light having a wavelength of 442 nm from the reflective element 1013 to the input fiber 1018 side.

Note that an antireflection film having a reflectance of about 0.5% in the wavelength range of 400 nm to 700 nm is formed on the end face of the semiconductor light emitting element 1004 on the reflective element 1006 side.

The light emitting medium 1005 is fused at a fusion point 1021 to an input fiber 1018 which is a quartz fiber having a lensed fiber 1016 having a compound cylindrical lens shape having a curvature radius of 3 μm (longitudinal correction) and a curvature radius of 7 μm (lateral correction). The output fiber 1017 having the reflection element 1020 made of FBG and the fusion point 1019 are fusion-connected. The parameters of the quartz fiber used for the input fiber 1018 and the output fiber 1017 are NA = 0.2 and a core diameter of 4 μm.

The surface of the lensed fiber 1016 is formed with a dispersion compensation film made of CaF ₂ and BaF ₂ in order to suppress focal position fluctuations due to chromatic aberration of wavelengths 442 nm and 520 nm, and further, a laser beam wavelength of 520 nm and excitation light. An antireflection film having a reflectance of about 1% at a wavelength of 442 nm is formed.

Excitation light emitted from the semiconductor laser resonator 1001 is incident on the light emitting medium 1005 with a divergence angle corrected by a lensed fiber 1016 installed close to the excitation light emission region, and is coupled to the core of the fiber. Conversely, laser light having a wavelength of 520 nm emitted from the lensed fiber 1016 is substantially coupled to the active layer of the semiconductor light emitting device 1004.

Fluorescence having a wavelength of 520 nm emitted forward from the light emitting medium 1005 is folded back by the reflecting element 1020 which is a fiber diffraction grating having a reflectance of 50% at a wavelength of 520 nm, and is amplified in the light emitting medium 1005. The reflecting element 1006 -the reflecting element 1013 -the lensed fiber 1016 -the light emitting medium 1005 -the reflecting element 1020 constitutes a Fabry-Perot type solid-state laser resonator 1002. Laser light having a center wavelength of 520 nm propagates through the output fiber 1017 through the reflecting element 1020 which is a partial reflecting mirror, and is output 1003 from the fiber end. Note that the bandwidth of the reflection element 1020, which is a fiber diffraction grating, was 0.08 nm when the maximum value of reflectance was defined as the center wavelength and the wavelength width that was ½ of the maximum reflectance.

In this configuration, first, the reflecting element 1006 was adjusted so that the output of the semiconductor laser resonator 1001 was maximized. At this time, the pumping light power radiated from the semiconductor laser resonator 1001 was 250 mW at the maximum. After adjusting the semiconductor laser resonator 1001, adjusting the position, angle, and distance from the semiconductor light emitting element of the lensed fiber 1016 while measuring the power of the laser output 1003 not only provides laser oscillation, but also easily Power optimization was possible. At this time, the time required for adjustment of the solid-state laser resonator 1002 until the start of laser oscillation was only 1 minute, and power optimization was achieved in 3 minutes, and a maximum output of 32 mW was obtained. Further, the line width of the solid-state laser output was 0.1 nm which is extremely close to the bandwidth of the fiber diffraction grating when the maximum output wavelength is the center wavelength and the wavelength width is ½ of the output.

INDUSTRIAL APPLICABILITY The present invention can be used as an observation or analysis light source used in the medical, bio, healthcare, and biological fields, an industrial inspection light source, a television, a display or projector light source, a light source for an optical gyroscope, a light source for fine processing, .

Claims

A semiconductor light source including a semiconductor light emitting element that emits excitation light;
A light emitting medium that emits light by absorbing the excitation light, wherein the light emitting medium outputs at least a part of the light emission as output light;
A first optical resonator configured by a first reflecting element set to form a first optical path for resonating the excitation light and enhancing its light intensity;
A laser light source device comprising a second optical resonator configured by a second reflecting element group, wherein a second optical path for resonating light emission of the light emitting medium to enhance its light intensity is provided,
The first optical path and the second optical path share a part, and the semiconductor light emitting element is disposed in the shared part,
The luminescent medium is disposed in the second optical path;
A laser light source device in which the first reflecting element group and the second reflecting element group share at least the first reflecting element, and the first reflecting element reflects both the output light and the excitation light.
The first optical resonator and the second optical resonator are both Fabry-Perot type optical resonators,
The first reflective element set has a second reflective element other than the first reflective element, the second reflective element constitutes a light emitting end of the first optical resonator, and the second reflective element is The reflectance of light having a desired oscillation wavelength of the first optical resonator is lower than that of the first reflective element,
The second reflective element set includes a third reflective element other than the first reflective element, the third reflective element constitutes a light emitting end of the second optical resonator, and the third reflective element includes the The laser light source device according to claim 1, wherein the reflectance of light having a desired oscillation wavelength of the second optical resonator is lower than that of the first reflecting element.