JP2021034530A - Laser module and fiber laser device - Google Patents

Abstract

To provide an inexpensive laser module capable of stably outputting a laser beam with a desired wavelength.SOLUTION: A laser module 1 comprises: an optical fiber 14; a plurality of semiconductor laser elements 22A to 22F that are arranged at different heights; condenser lenses 32 and 34 that collect laser beams LA' to LF' ejected from the semiconductor laser elements 22A to 22F and make them couple to the optical fiber 14; a mirror 28 that reflects each of the laser beams LA to LF ejected from the semiconductor laser elements 22A to 22F and directs them to the condenser lens 32; and a plurality of wavelength stabilization elements 41 to 43 that achieve a narrow band of a wavelength of each of the laser beams LA to LF ejected from the semiconductor laser elements 22A to 22F. Each of the wavelength stabilization elements 41 to 43 is structured so as to achieve the narrow band of the wavelength of each laser beam ejected from two or more different semiconductor laser elements among the semiconductor laser elements 22A to 22F.SELECTED DRAWING: Figure 2

Description

The present invention relates to a laser module and a fiber laser device, and particularly relates to a laser module that collects and outputs laser light emitted from a plurality of semiconductor laser elements.

Conventionally, a laser module that collects laser light emitted from a plurality of semiconductor laser elements and outputs a high-power laser light has been known. Since the oscillation wavelength of the semiconductor laser element used in such a laser module fluctuates due to manufacturing variations and has temperature dependence, in order to stably output laser light of a desired wavelength, each of them is used. It is necessary to lock the wavelength of the laser beam output from the semiconductor laser element of the above to a specific wavelength. As one of the methods for locking the wavelength of the output laser light of a plurality of semiconductor laser elements, a specific wavelength stabilizing element called Volume Bragg Grating (VBG) whose refractive index changes periodically at a predetermined lattice interval is used. A method of selectively reflecting a wavelength is known (see, for example, Patent Document 1).

FIG. 1A is a diagram schematically showing an example of a configuration of a conventional laser module using such a VBG. In the conventional laser module shown in FIG. 1A, laser light B is emitted from a plurality of semiconductor laser elements 510 on submounts 500 arranged at different heights. The laser beam B is collimated by the fast-axis collimating lens 520 and the slow-axis collimating lens 530, and its propagation direction is changed by 90 degrees by the mirror 540. The directed laser beam B is condensed by the fast-axis condensing lens 550 and the slow-axis condensing lens 560 and coupled to the optical fiber 570.

Here, a wavelength stabilizing element (VBG) 590 is arranged between the mirror 540A located closest to the first-axis condensing lens 550, the first-axis condensing lens, and the 550. The wavelength stabilizing element 590 is configured to reflect a specific wavelength of the laser beam B from the mirror 540. As a result, an external resonator is formed between the reflecting surface of the wavelength stabilizing element 590 and the reflecting end surface of the active layer of the semiconductor laser element 510, and the narrowed wavelength laser light B'is the wavelength stabilizing element 590. Is output toward the first-axis condenser lens 550.

Here, in the configuration shown in FIG. 1A, the optical path lengths from the respective semiconductor laser elements 510 to the wavelength stabilizing element 590 are different. For example, the optical path length from the semiconductor laser element 510A to the wavelength stabilizing element 590 is the shortest, and the optical path length from the semiconductor laser element 510F to the wavelength stabilizing element 590 is the longest. As shown in FIG. 1A, the difference between these optical path lengths is D _max . Such a difference in the optical path length can cause a decrease in the coupling efficiency of the laser beam B'to the optical fiber 570. Further, the long optical path length, that is, the long resonator length tends to increase the waveguide loss of the external resonator and deteriorate the efficiency of the resonator. As shown in FIG. 1B, it is conceivable to provide a wavelength stabilizing element 590 for each semiconductor laser element 510 in order to prevent such a difference in optical path length, but the wavelength stabilizing element is expensive. Therefore, in the configuration shown in FIG. 1B, an increase in the manufacturing cost of the laser module due to a large number of wavelength stabilizing elements 590 becomes a problem. For example, it becomes necessary to accurately position each wavelength stabilizing element 590 with respect to the semiconductor laser element 510, which increases the man-hours for installing the wavelength stabilizing element 590.

U.S. Patent Application Publication No. 2016/0172823

The present invention has been made in view of such problems of the prior art, and a first object of the present invention is to provide an inexpensive laser module capable of stably outputting a laser beam having a desired wavelength. ..

A second object of the present invention is to provide an inexpensive fiber laser apparatus capable of stably outputting a laser beam having a desired wavelength.

According to the first aspect of the present invention, there is provided an inexpensive laser module capable of stably outputting a laser beam having a desired wavelength. This laser module includes an optical fiber, a plurality of semiconductor laser elements, a condenser lens that collects laser light emitted from the plurality of semiconductor laser elements and couples them to the optical fiber, and the plurality of semiconductor laser elements. Of these, a plurality of mirrors that reflect the laser light emitted from the corresponding semiconductor laser element and direct it toward the condenser lens, and a plurality of wavelengths that narrow the wavelength of the laser light emitted from the plurality of semiconductor laser elements. It is equipped with a stabilizing element. Each of the plurality of wavelength stabilizing elements is configured to narrow the wavelength of the laser light emitted from two or more different semiconductor laser elements among the plurality of semiconductor laser elements.

According to such a configuration, since a plurality of wavelength stabilizing elements are used for a plurality of semiconductor laser elements, the wavelength stabilizing element and the semiconductor laser element can be used as compared with the case where a single wavelength stabilizing element is used. The difference in the optical path lengths of the laser beams between them can be reduced. Therefore, it is suppressed that the coupling efficiency of the laser beam to the optical fiber is lowered due to the difference in the optical path length. Further, since each of the plurality of wavelength stabilizing elements narrows the wavelength of the laser light emitted from two or more different semiconductor laser elements, the required number of wavelength stabilizing elements can be determined by the semiconductor laser element. It can be suppressed to less than half of the total number. Therefore, the man-hours for installing the wavelength stabilizing element are reduced, so that the manufacturing cost of the laser module can be suppressed.

The laser module may further include a plurality of collimating lenses that collimate the laser light emitted from the corresponding semiconductor laser element among the plurality of semiconductor laser elements. In this case, even if the plurality of wavelength stabilizing elements are arranged on the downstream side of the corresponding collimating lens and the corresponding mirror in the optical path from each of the two or more semiconductor laser elements to the optical fiber. Good. In this case, the laser beam reflected by each wavelength stabilizing element returns to the focal position of the collimating lens, that is, each active layer of the corresponding semiconductor laser element by the corresponding collimating lens. Therefore, the amount of laser light returning to the outside of the active layer of the semiconductor laser element is reduced, and an efficient external resonator can be formed.

In order to effectively reduce the difference in optical path length between the wavelength stabilizing element and the semiconductor laser element, it is preferable that the two or more semiconductor laser elements are two or more semiconductor laser elements adjacent to each other.

According to the second aspect of the present invention, there is provided an inexpensive laser module capable of stably outputting a laser beam having a desired wavelength. This laser module is emitted from an optical fiber, a plurality of first semiconductor laser elements, a plurality of corresponding second semiconductor laser elements among the plurality of first semiconductor laser elements, and the plurality of first semiconductor laser elements. A condensing lens that condenses the laser light and the laser light emitted from the plurality of second semiconductor laser elements and couples them to the optical fiber, and the laser light emitted from the plurality of first semiconductor laser elements and the above A photosynthesis unit that synthesizes laser light emitted from a plurality of second semiconductor laser elements and directs them toward the condenser lens, and a photosynthesis unit that reflects laser light emitted from the plurality of second semiconductor laser elements and directs the light to the photosynthesis unit. Auxiliary mirrors to be directed, a plurality of first mirrors that reflect laser light emitted from the corresponding first semiconductor laser element among the plurality of first semiconductor laser elements and directed to the photosynthesis unit, and the plurality of second semiconductors. A plurality of second mirrors that reflect laser light emitted from a corresponding second semiconductor laser element among the laser elements and direct them toward the auxiliary mirror, the plurality of first semiconductor laser elements, and the plurality of second semiconductor laser elements. It is provided with a plurality of wavelength stabilizing elements for narrowing the wavelength of the laser beam emitted from the device. Each of the plurality of wavelength stabilizing elements includes laser light emitted from one or more of the first semiconductor laser elements of the plurality of first semiconductor laser elements, and one or more of the plurality of second semiconductor laser elements. The wavelength of the laser light emitted from one or more second semiconductor laser elements corresponding to the first semiconductor laser element is narrowed.

According to such a configuration, since a plurality of wavelength stabilizing elements are used for a plurality of semiconductor laser elements, the wavelength stabilizing element and the semiconductor laser element can be used as compared with the case where a single wavelength stabilizing element is used. The difference in the optical path lengths of the laser beams between them can be reduced. Therefore, it is suppressed that the coupling efficiency of the laser beam to the optical fiber is lowered due to the difference in the optical path length. Further, each of the plurality of wavelength stabilizing elements has a wavelength of laser light emitted from one or more first semiconductor laser elements and one or more second semiconductor laser elements corresponding to the one or more first semiconductor laser elements. Since the wavelength of the laser light emitted from the LED is narrowed, positioning work is required and an increase in the number of wavelength stabilizing elements, which are also expensive parts, can be suppressed, so that the manufacturing cost of the laser module can be suppressed. be able to. Further, since the laser light emitted from the first semiconductor laser element and the laser light emitted from the second semiconductor laser element are combined by the photosynthesis unit, it is possible to output a higher power laser beam. ..

For efficient arrangement, it is preferable that the one or more first semiconductor laser elements and the one or more second semiconductor laser elements are arranged at the same height. In this case, since the surface on which the wavelength stabilizing element is installed can be made flat, the installation work of the wavelength stabilizing element becomes easy.

The laser module corresponds to a plurality of first collimating lenses that collimate the laser light emitted from the corresponding first semiconductor laser element among the plurality of first semiconductor laser elements, and the plurality of second semiconductor laser elements. A plurality of second collimating lenses that collimate the laser light emitted from the second semiconductor laser element may be further provided. Each of the plurality of wavelength stabilizing elements is on the downstream side of the corresponding first collimating lens and the corresponding first mirror in the optical path from the one or more first semiconductor laser elements to the optical fiber. Moreover, in the optical path from the first or more second semiconductor laser element to the optical fiber, it may be arranged on the downstream side of the corresponding second collimating lens and the corresponding second mirror.

In order to effectively reduce the difference in optical path length between the wavelength stabilizing element and the semiconductor laser element and reduce the number of wavelength stabilizing elements, the first semiconductor laser elements of 1 or more are adjacent to each other. It is preferable that the two or more first semiconductor laser elements, and the one or more second semiconductor laser elements are two or more second semiconductor laser elements adjacent to each other.

According to the third aspect of the present invention, there is provided an inexpensive fiber laser apparatus capable of stably outputting a laser beam having a desired wavelength. This fiber laser apparatus includes an excitation light source including the above-mentioned laser module, and an amplification optical fiber connected to the above-mentioned optical fiber of the above-mentioned laser module and having a core to which rare earth element ions are added.

According to the present invention, an inexpensive laser module capable of stably outputting a laser beam having a desired wavelength can be obtained.

FIG. 1A is a diagram schematically showing an example of the configuration of a conventional laser module. FIG. 1B is a diagram schematically showing another example of the configuration of a conventional laser module. FIG. 2 is a partial cross-sectional plan view schematically showing the laser module according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA of FIG. FIG. 4 is a graph showing the relationship between the optical path length between the wavelength stabilizing element and the semiconductor laser element and the beam width in the slow axis direction. FIG. 5 is a partial cross-sectional plan view schematically showing the laser module according to the second embodiment of the present invention. FIG. 6 is a schematic view showing an example of a fiber laser apparatus using the laser module according to the present invention.

Hereinafter, embodiments of the laser module and the fiber laser apparatus according to the present invention will be described in detail with reference to FIGS. 2 to 6. In FIGS. 2 to 6, the same or corresponding components are designated by the same reference numerals, and duplicate description will be omitted. Further, in FIGS. 2 to 6, the scale and dimensions of each component may be exaggerated or some components may be omitted.

FIG. 2 is a partial cross-sectional plan view schematically showing the laser module 1 according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. As shown in FIGS. 2 and 3, the laser module 1 includes a housing 10, a stepped pedestal 12 arranged inside the housing 10, an optical fiber 14 extending inside the housing 10, and light. It includes a fiber mount 16 for fixing the fiber 14 and a cylindrical fiber holding portion 18 for holding the optical fiber 14. The optical fiber 14 is fixed on the fiber mount 16 by an adhesive 19 or the like. A lid (not shown) is arranged on the upper part of the housing 10, and the internal space of the housing is sealed by the lid.

The pedestal 12 has six step portions 12A to 12F having different heights in the Z direction, and in the present embodiment, the step portions are gradually raised from the first step portion 12A in the −X direction. 12A to 12F are formed. Each stepped portion 12A~12F is disposed submount 20, over each of the sub-mount 20, the semiconductor laser element 22A~22F which emits a laser beam L _A ~L _F is placed on the + Y direction ing. In the present specification, unless otherwise specified, the direction in which the laser beam is emitted from each of the semiconductor laser elements 22A to 22F toward the optical fiber 14 is referred to as the "downstream side", and the direction opposite to that. Is referred to as the "upstream side".

Further, each stepped portion 12A~12F of the base 12, corresponding to the semiconductor laser element 22A-22F, collimates the laser beam L _A ~L _F emitted from the semiconductor laser element 22A-22F in the fast axis direction The fast-axis collimating lens 24, the slow-axis collimating lens 26 that collimates _{the laser beams L A to} L _F transmitted through the fast-axis collimating lens 24 in the _{slow-axis direction, and the laser light L A to} L transmitted through the slow-axis collimating lens 26. A mirror 28 that changes the propagation direction of _{F by 90 degrees is arranged.}

Further, between the end surface of the optical fiber 14 extending inside the housing 10 and the first step portion 12A of the pedestal 12, the laser beams L _{A to} L _F reflected by the mirror 28 are collected in the first axial direction. a first-axis condenser lens 32, the laser beam L _a ~L _F and then focused on the slow axis direction slow axis condenser lens is attached to the end face of the optical fiber 14 34 are disposed.

Here, the laser module 1 in the present embodiment has wavelength stabilizing elements (VBG) 41 to 43 whose refractive index changes periodically at predetermined lattice intervals. These wavelength stabilizing elements 41 to 43 are configured to reflect a specific wavelength (for example, 976 nm).

The wavelength stabilizing element 41 is arranged on the + X direction side of the mirror 28 of the first stage portion 12A of the pedestal 12, and is arranged on the optical path of the two laser beams, that is, on the first stage portion 12A. It was located on the optical path of the laser beam L _B emitted from the laser light L _a and second stage of the semiconductor laser device 22B arranged in the stepped portion 12B is emitted from the semiconductor laser element 22A. In other words, the wavelength stabilizing element 41 is disposed on the downstream side of the slow axis collimating lens 26 and the mirror 28 on the optical path of the optical path and the laser beam L _B of the laser light L _A.

The wavelength stabilizing element 42 is arranged on the + X direction side of the mirror 28 of the third stage portion 12C of the pedestal 12, and is arranged on the optical path of the two laser beams, that is, on the third stage portion 12C. It was located on the optical path of the laser beam L _D emitted from the laser light L _C and the semiconductor laser element 22D disposed in the stepped portion 12D of the fourth stage is emitted from the semiconductor laser device 22C. In other words, the wavelength stabilizing element 42 is disposed on the downstream side of the slow axis collimating lens 26 and the mirror 28 on the optical path of the optical path and the laser light L _D of the laser beam L _C.

The wavelength stabilizing element 43 is arranged on the + X direction side of the mirror 28 of the fifth stage portion 12E of the pedestal 12, and is arranged on the optical path of the two laser beams, that is, on the fifth stage portion 12E. It was located on the optical path of the laser beam L _F emitted from the laser beam emitted L _E and arranged semiconductor laser device 22F on the step portion 12F of the sixth-stage from the semiconductor laser device 22E. In other words, the wavelength stabilizing element 43 is disposed on the downstream side of the slow axis collimating lens 26 and the mirror 28 on the optical path of the optical path and the laser beam L _F of the laser beam L _E.

In such a configuration, the semiconductor laser device 22A laser light L _A emitted in the + Y direction from is collimated in the fast axis direction and slow axis direction by fast axis collimating lens 24 and the slow axis collimating lens 26, the mirror 28 It is turned 90 degrees and propagates in the + X direction. The laser light L _A back toward the semiconductor laser element 22A is reflected by the wavelength stabilizing element 41, an external resonator between the reflecting end face of the active layer of the reflecting surface and the semiconductor laser device 22A having a wavelength stabilizing element 41 Is formed. Thus, the wavelength is narrowed laser beam L _A 'is output from the wavelength stabilizing element 41 in the + X direction.

Similarly, the laser beam L _B emitted from the semiconductor laser element 22B in the + Y direction, propagates through the fast axis collimating lens 24 and the slow axis collimating lens 26 after passing through, by the mirror 28 in the direction of 90 degrees turning has been the + X direction, It is reflected by the wavelength stabilizing element 41. Thus, an external resonator formed between the reflecting end face of the active layer of the reflecting surface and the semiconductor laser element 22B of the wavelength stabilizing element 41, the wavelength is narrowed laser beam L _B 'is the wavelength stabilizing element It is output from 41 in the + X direction.

The laser beam L _D emitted in the + Y direction from the semiconductor laser device 22C laser beam emitted in the + Y direction from L _C, and a semiconductor laser element 22D, respectively passed through the fast axis collimating lens 24 and the slow axis collimating lens 26 , 90 degrees turned by the mirror 28, propagated in the + X direction, reflected by the wavelength stabilizing element 42, and between the reflecting surface of the wavelength stabilizing element 42 and the reflecting end surface of the active layer of the semiconductor laser elements 22C and 22D. An external resonator is formed. As a result, the laser beams L _C'and L _D' with narrowed wavelengths are output from the wavelength stabilizing element 42 in the + X direction. Further, the laser beam L _F emitted from the semiconductor laser element 22E + Y direction emitted from the laser beam L _E and the semiconductor laser device 22F in the + Y direction, respectively passed through the fast axis collimating lens 24 and the slow axis collimating lens 26 , 90 degrees turned by the mirror 28, propagated in the + X direction, reflected by the wavelength stabilizing element 43, and between the reflecting surface of the wavelength stabilizing element 43 and the reflecting end surface of the active layer of the semiconductor laser elements 22E and 22F. An external resonator is formed. Thus, the laser beam L _E wavelength is narrowed ', L _F' is outputted from the wavelength stabilizing element 43 in the + X direction.

Thus, the wavelength stabilizing element 41 in this embodiment, is configured to narrowing the wavelength of the laser light L _A, L _B emitted from two different semiconductor laser device 22A, 22B, wavelength stabilizing element 42 is configured to narrowing the wavelength of the laser light L _C, L _D emitted from two different semiconductor laser device 22C, 22D. The wavelength stabilizing element 43 is configured to narrowing the wavelength of the laser beam L _E, L _F emitted different two semiconductor laser elements 22E, from 22F to each other.

These laser light wavelengths are narrowed in wavelength stabilizing elements 41~43 L _A '~L _F' is condensed in fast axis by fast axis converging lens 32, further by the slow axis converging lens 34 It is focused on the slow axis. Thus, these laser light L _A '~L _F' are optically coupled to the end face of the optical fiber 14.

By the way, recently, in the conventional configuration shown in FIG. 1A, the optical path length from each semiconductor laser element 510 to the wavelength stabilizing element 590 is different, so that the coupling efficiency of the laser light B'to the optical fiber 570 is lowered. It is becoming clear. For example, FIG. 4 is a graph showing the relationship between the optical path length of the laser beam between the semiconductor laser element 510 and the wavelength stabilizing element 590 and the beam width in the slow axis direction at a distance. As shown in FIG. 4, the beam width at a distance changes depending on the optical path length between the semiconductor laser element 510 and the wavelength stabilizing element 590. As described above, in the conventional configuration shown in FIG. 1A, the difference in the optical path length between the wavelength stabilizing element 590 and each semiconductor laser element 510 is large, so that the beam width of the laser beam B'coupled to the optical fiber 570 is large. Fluctuations also increase. As a result, the coupling efficiency of the laser beam B'to the optical fiber 570 is lowered.

On the other hand, in the present embodiment, since three wavelength stabilizing elements 41 to 43 are used for the six semiconductor laser elements 22A to 22F, the wavelength is stable as compared with the conventional laser module shown in FIG. 1A. The difference in optical path length between the chemical elements 41 to 43 and the semiconductor laser elements 22A to 22F can be reduced. For example, regarding the wavelength stabilizing element 41, the optical path length between the wavelength stabilizing element 41 and the semiconductor laser element 22B is d ₁ longer than the optical path length between the wavelength stabilizing element 41 and the semiconductor laser element 22A. _However , it is very small compared to the maximum value D max of the difference in the optical path length in the conventional laser module shown in FIG. 1A. Therefore, it is possible to reduce the fluctuation of the beam width in the slow axis direction that may occur due to the difference in the optical path length of the laser beam, and as a result, it is possible to suppress the decrease in the coupling efficiency of the laser beam to the optical fiber 14. Can be done.

Here, in order to reduce the difference in the optical path length between the wavelength stabilizing element and the semiconductor laser element, as in the present embodiment, the wavelength stabilizing element 41 and the semiconductor laser element 22A adjacent to each other in the X direction are used. It is preferable that the wavelength of the laser light emitted from the semiconductor laser element 22B is narrowed. Similarly, the wavelength stabilizing element 42 is preferably configured to narrow the wavelength of the laser light emitted from the semiconductor laser element 22C and the semiconductor laser element 22D that are adjacent to each other in the X direction. The stabilizing element 43 is preferably configured to narrow the wavelength of the laser light emitted from the semiconductor laser element 22E and the semiconductor laser element 22F that are adjacent to each other in the X direction.

Further, in the present embodiment, since each of the plurality of wavelength stabilizing element 41 to 43, the wavelength of the laser beam L _A ~L _F emitted from two different semiconductor laser element 22A~22F is narrowed, The number of wavelength stabilizing elements required can be reduced to half of the total number of semiconductor laser elements 22A to 22F, that is, three. Therefore, according to the present embodiment, the man-hours for installing the wavelength stabilizing element are reduced, so that the manufacturing cost of the laser module 1 can be suppressed.

Further, in the present embodiment, since each of the wavelength stabilizing elements 41 to 43 is arranged on the downstream side of the slow axis collimating lens 26, the laser light reflected by the respective wavelength stabilizing elements 41 to 43 is generated. The slow-axis collimating lens 26 returns to the focal position of the slow-axis collimating lens 26, that is, the active layers of the semiconductor laser devices 22A to 22F. Therefore, the amount of laser light returning to the outside of the active layer of the semiconductor laser elements 22A to 22F is reduced, and an efficient external resonator can be formed.

FIG. 5 is a partial cross-sectional plan view schematically showing the laser module 101 according to the second embodiment of the present invention. The laser module 101 has semiconductor laser elements 122A to 122F (second semiconductor laser element) in addition to the semiconductor laser elements 22A to 22F (first semiconductor laser element) in the first embodiment described above. That is, as shown in FIG. 5, each of the stepped portions 12A~12F of the pedestal 12 is arranged submount 120, on each of the sub-mount 120, the laser beam M _A ~M _F in the -Y direction The semiconductor laser elements 122A to 122F that emit light are mounted.

The semiconductor laser element 122A is arranged so as to face the semiconductor laser element 22A at the same height as the semiconductor laser element 22A, and the semiconductor laser element 122B faces the semiconductor laser element 22B at the same height as the semiconductor laser element 22B. It is arranged to do. Further, the semiconductor laser element 122C is arranged so as to face the semiconductor laser element 22C at the same height as the semiconductor laser element 22C, and the semiconductor laser element 122D is arranged at the same height as the semiconductor laser element 22D. It is arranged so as to face the. Further, the semiconductor laser element 122E is arranged so as to face the semiconductor laser element 22E at the same height as the semiconductor laser element 22E, and the semiconductor laser element 122F is arranged at the same height as the semiconductor laser element 22F. It is arranged so as to face the.

Further, each stepped portion 12A~12F of the base 12, corresponding to the semiconductor laser element 122A～122F, collimates the laser beam M _A ~M _F emitted from the semiconductor laser element 122A～122F the fast axis direction The fast-axis collimating lens 124, the slow-axis collimating lens 126 that collimates _{the laser beams M A to} M _F transmitted through the fast-axis collimating lens 124 in the _{slow-axis direction, and the laser light M A to} M transmitted through the slow-axis collimating lens 126. A mirror 128 that changes the propagation direction of _{F by 90 degrees is arranged.}

Further, between the mirror 28 on the first stage portion 12A of the pedestal 12 and the first axis condensing lens 32, the laser light from the semiconductor laser elements 22A to 22F and the laser light from the semiconductor laser elements 122A to 122F A beam splitter 150 is arranged as a photosynthesizing unit for synthesizing and directing to the first axis condensing lens 32, and a semiconductor laser element is placed on the + X direction side of the mirror 128 on the first stage portion 12A of the pedestal 12. _{An auxiliary mirror 152 that reflects the laser beams M A to} M _F emitted from 122 A to 122 F and directs them toward the beam splitter 150 is arranged. A 1/2 wave plate (not shown) is arranged between the beam splitter 150 and the auxiliary mirror 152. As the photosynthetic unit described above, an optical component such as a dichroic mirror can be used instead of the beam splitter 150 shown in the present embodiment.

The laser module 101 in this embodiment has wavelength stabilizing elements 141 to 143 configured to reflect a specific wavelength (for example, 976 nm). The wavelength stabilizing element 141 is arranged on the + X direction side of the mirror 28 (first mirror) and the mirror 128 (second mirror) of the first stage portion 12A of the pedestal 12, and extends in the Y direction. The wavelength stabilizing element 141, four laser beam on the optical path, i.e., the laser light L _A emitted from the semiconductor laser device 22A arranged in the first stage of the step portion 12A, facing the semiconductor laser device 22A the semiconductor laser element 122A laser beam L _B emitted from the laser beam M _a, arranged in the second stage of the stepped portion 12B the semiconductor laser device 22B emitted from the semiconductor laser element 122B that faces the semiconductor laser device 22B It is located on the optical path of the laser beam M _B emitted. In other words, the wavelength stabilizing element 141, the optical path of the laser beam L _A, the optical path of the laser beam M _A, the laser beam L _B of the optical path, and corresponding slow axis collimating lens in the optical path of the laser beam M _B It is located downstream of 26,126 and the corresponding mirrors 28,128.

The wavelength stabilizing element 142 is arranged on the + X direction side of the mirror 28 and the mirror 128 of the third stage portion 12C of the pedestal 12, and extends in the Y direction. The wavelength stabilizing element 142, four laser beam on the optical path, i.e., the laser light L _C emitted from the semiconductor laser device 22C which is disposed on the step portion 12C of the third stage, facing the semiconductor laser device 22C the semiconductor laser element 122C laser light L _D emitted from the semiconductor laser element 22D disposed in the laser beam M _C, 4-stage stepped portion 12D which is emitted from the semiconductor laser element 122D that faces the semiconductor laser element 22D It is located on the optical path of the laser beam M _D emitted. In other words, the wavelength stabilizing element 142, the optical path of the laser beam L _C, the optical path of the laser beam M _C, the optical path of the laser beam L _D, and corresponding slow axis collimating lens in the optical path of the laser beam M _D It is located downstream of 26,126 and the corresponding mirrors 28,128.

The wavelength stabilizing element 143 is arranged on the + X direction side of the mirror 28 and the mirror 128 of the fifth stage portion 12E of the pedestal 12, and extends in the Y direction. The wavelength stabilizing element 143, four laser beam on the optical path, i.e., the laser beam L _E emitted from the semiconductor laser element 22E disposed in the stepped portion 12E of the fifth stage, facing the semiconductor laser element 22E the semiconductor laser element laser beam M _E emitted from 122E, 6-stage step portions 12F on the laser light L _F emitted from the positioned semiconductor laser element 22F, the semiconductor laser element 122F opposite to the semiconductor laser device 22F It is located on the optical path of the laser beam M _F emitted. In other words, the wavelength stabilizing element 143, an optical path of the laser beam L _E, the optical path of the laser beam M _E, the laser beam L _F of the optical path, and corresponding slow axis collimating lens in the optical path of the laser beam M _F It is located downstream of 26,126 and the corresponding mirrors 28,128.

Also, as in the first embodiment described above, the semiconductor laser element laser beam L _A ~L emitted from 22A-22F _F after passing through the fast axis collimating lens 24 and the slow axis collimating lens 26, respectively, the mirror 28 the propagated to 90 degrees turning has been the + X direction, the laser beam L _a '~L _F' which wavelengths are narrowed by the wavelength stabilizing element 141-143.

The semiconductor laser element 122A laser beam M _A which is emitted in the -Y direction from, after passing through the first axis collimating lens 124 and the slow-axis collimating lens 126, the mirror 128 propagates in the 90-degree direction change has been the + X direction, wavelength stability wavelength is narrowed laser beam M _a 'by reduction element 141. Similarly, the semiconductor laser element 122B laser beam M _B emitted in the -Y direction from propagates fast axis collimating lens 124 and the slow-axis collimating lens 126 after passing by the mirror 128 in the 90-degree direction change has been the + X direction , wavelength is narrowed laser beam M _B 'by the wavelength stabilizing element 141.

The semiconductor laser element 122C laser light emitted in the -Y direction from M _C and the laser beam M _D emitted from the semiconductor laser element 122D in the -Y direction, a fast axis collimating lens 124 and the slow-axis collimating lens 126, respectively after passing by the mirror 128 90 ° redirected + X propagates in the direction, the laser beam M _C which wavelength is narrowed by wavelength stabilizing element 142 ', M _D' becomes.

The semiconductor laser element laser beam M _E emitted in the -Y direction from 122E and a semiconductor laser element laser beam M _F emitted in the -Y direction from 122F after passing through the first axis collimating lens 124 and the slow-axis collimating lens 126, respectively , by the mirror 128 propagates in the 90-degree direction change has been the + X direction, the laser beam M _E wavelength by the wavelength stabilizing element 143 is narrowed ', M _F' becomes.

Wavelength narrowed laser beam M _A '~M _F' is 90 degrees diverted by the auxiliary mirror 152 propagates in the -Y direction, after being polarized by 1/2-wave plate, the beam splitter 150 is polarization combining the laser light L _a '~L _F' is outputted to the fast axis condenser lens 32 by. These laser light L _A '~L _F' in fast axis converging lens 32 and the M _A '~M _F' is condensed in fast axis, it is focused on the slow axis further by the slow axis converging lens 34. Thus, these laser light L _A '~L _F' and M _A '~M _F' are optically coupled to the end face of the optical fiber 14.

The wavelength stabilizing element 141 in this embodiment, two semiconductor laser elements 22A adjacent to each other, the laser beam L _A, L _B emitted from 22B, the two semiconductor laser elements 22A, 22B of the same respectively two semiconductor laser elements 122A, which is disposed at a height, the laser beam M _a emitted from 122B, are configured to narrowing the wavelength of the M _B. The wavelength stabilizing element 142 includes a laser light L _C, L _D emitted from the two semiconductor laser elements 22C, 22D adjacent to each other, these two semiconductor laser elements 22C, disposed 22D respectively same height two semiconductor laser elements 122C is, the laser beam M _C emitted from 122D, is configured to narrowing the wavelength of M _D, wavelength stabilizing element 143, two semiconductor laser elements adjacent to each other 22E, the laser beam L _E emitted from 22F, L _F and, the two semiconductor laser elements 22E, two semiconductor laser elements 122E disposed respectively 22F same height, the laser beam M emitted from 122F _E, is configured to narrowing the wavelength of the M _F.

In this embodiment, since three wavelength stabilizing elements 141 to 143 are used for the 12 semiconductor laser elements 22A to 22F and 122A to 122F, the wavelength is stable as compared with the conventional laser module shown in FIG. 1A. The difference in optical path length between the chemical elements 141 to 143 and the semiconductor laser elements 22A to 22F and 122A to 122F can be reduced. Therefore, it is possible to reduce the fluctuation of the beam width in the slow axis direction that may occur due to the difference in the optical path length of the laser beam, and as a result, it is possible to suppress the decrease in the coupling efficiency of the laser beam to the optical fiber 14. Can be done.

Further, in the present embodiment, each of the plurality of wavelength stabilizing elements 141 to 143 narrows the wavelength of the laser light emitted from the four different semiconductor laser elements, so that the wavelength stabilizing element is required. Can be 1/4 of the total number of semiconductor laser elements 22A to 22F and 122A to 122F, that is, three. Therefore, according to the present embodiment, the man-hours for installing the wavelength stabilizing element are reduced, so that the manufacturing cost of the laser module 101 can be suppressed.

Further, in the laser module 101 of the present embodiment, the laser beam M _A is emitted from the semiconductor laser device the laser light emitted from 22A~22F L _A '~L _F' from the semiconductor laser element 122A~122F '~M _F' Is synthesized by the beam splitter 150, so that it is possible to output a laser beam having a higher power than the laser module 1 of the first embodiment described above.

The laser module 1 or 101 described above can be used, for example, in a fiber laser device or the like. FIG. 6 is a schematic view showing an example of a fiber laser apparatus using the laser module according to the present invention. The fiber laser apparatus 401 shown in FIG. 6 includes an optical resonator 410, a plurality of forward excitation light sources 420A for introducing excitation light into the optical resonator 410 from the front of the optical resonator 410, and the front of the optical resonator 410 via the optical fiber 421A. A front in-line combiner 422A to which the excitation light source 420A is connected, a plurality of rear excitation light sources 420B for introducing excitation light into the optical resonator 410 from behind the optical resonator 410, and these rear excitation light sources 420B via an optical fiber 421B. Is provided with a rear inline combiner 422B to which the is connected. The laser module 1 or 101 described above can be used as the forward excitation light source 420A and the rear excitation light source 420B.

The optical resonator 410 includes an amplification optical fiber 412 having a core to which rare earth element ions such as itterbium (Yb), erbium (Er), turium (Tr), and neodymium (Nd) are added, and an amplification optical fiber 412. It is composed of a high-reflection fiber bragg grading (high-reflection FBG) 414 connected to the front in-line combiner 422A and a low-reflection fiber brag grading (low-reflection FBG) 416 connected to the amplification optical fiber 412 and the rear in-line combiner 422B. Has been done. For example, the amplification optical fiber 412 is composed of a double clad fiber having an inner clad formed around the core and an outer clad formed around the inner clad.

Further, the fiber laser apparatus 401 further includes a delivery fiber 430 extending from the rear in-line combiner 422B, and the end portion of the delivery fiber 430 on the wake side is, for example, covered with laser oscillation light from the amplification optical fiber 412. A laser output unit 460 that emits light toward the processed object is provided.

The front in-line combiner 422A and the rear in-line combiner 422B combine the excitation lights output from the front excitation light source 420A and the rear excitation light source 420B, respectively, and introduce them into the inner cladding of the amplification optical fiber 412 described above. As a result, the excitation light propagates inside the inner clad of the amplification optical fiber 412.

The high-reflection FBG414 is formed by periodically changing the refractive index of the optical fiber, and reflects light in a predetermined wavelength band with a reflectance close to 100%. Like the high-reflection FBG414, the low-reflection FBG416 is formed by periodically changing the refractive index of the optical fiber, and allows a part of the light in the wavelength band reflected by the high-reflection FBG414 to pass through and the rest. It is a reflection. In this way, the high-reflection FBG414, the amplification optical fiber 412, and the low-reflection FBG416 recursively amplify the light in a specific wavelength band between the high-reflection FBG414 and the low-reflection FBG416 to generate laser oscillation. The resonator 410 is configured.

In the example shown in FIG. 6, excitation light sources 420A and 420B and combiners 422A and 422B are provided on both the high-reflection FBG414 side and the low-reflection FBG416 side, which is a bidirectional excitation type fiber laser apparatus, but is high. The excitation light source and the combiner may be installed only on either the reflection FBG414 side or the low reflection FBG416 side. Further, a mirror can be used instead of the FBG as a reflection means for oscillating the laser in the optical resonator 410.

Further, as a fiber laser device, a MOPA fiber laser device that amplifies seed light from a seed light source by using excitation light from an excitation light source is also known, and the above-mentioned laser module is a MOPA fiber laser device of such a MOPA fiber laser device. It can also be used as an excitation light source.

Although the preferred embodiment of the present invention has been described so far, it goes without saying that the present invention is not limited to the above-described embodiment and may be implemented in various different forms within the scope of the technical idea.

1 Laser module 10 Housing 12 Pedestal 12A-12F Step 14 Optical fiber 20 Submount 22A-22F Semiconductor laser element (first semiconductor laser element)
24 First axis collimating lens 26 Slow axis collimating lens 28 Mirror (1st mirror)
32 First-axis condensing lens 34 Slow-axis condensing lens 41-43 Wave stabilization element 101 Laser module 120 Submount 122A to 122F Semiconductor laser element (second semiconductor laser element)
124 First axis collimating lens 126 Slow axis collimating lens 128 Mirror (second mirror)
141-143 Wavelength stabilizing element 150 Beam splitter (photosynthesis unit)
152 Auxiliary mirror 401 Fiber laser device 410 Optical resonator 412 Amplification optical fiber 414 High reflection FBG
416 Low reflection FBG
420A, 420B Excitation light source 421A, 421B Optical fiber 422A, 422B In-line combiner 430 Delivery fiber 460 Laser output unit

Claims (8)

With optical fiber
With multiple semiconductor laser devices,
A condenser lens that collects laser light emitted from the plurality of semiconductor laser elements and couples the laser light to the optical fiber.
A plurality of mirrors that reflect the laser beam emitted from the corresponding semiconductor laser element among the plurality of semiconductor laser elements and direct them toward the condenser lens.
A plurality of wavelength stabilizing elements for narrowing the wavelength of the laser light emitted from the plurality of semiconductor laser elements are provided.
Each of the plurality of wavelength stabilizing elements is configured to narrow the wavelength of the laser light emitted from two or more different semiconductor laser elements among the plurality of semiconductor laser elements.
Laser module. A plurality of collimating lenses for collimating the laser light emitted from the corresponding semiconductor laser element among the plurality of semiconductor laser elements are further provided.
The plurality of wavelength stabilizing elements are arranged on the downstream side of the corresponding collimating lens and the corresponding mirror in the optical path from each of the two or more semiconductor laser elements to the optical fiber.
The laser module according to claim 1. The laser module according to claim 1 or 2, wherein the two or more semiconductor laser elements are two or more semiconductor laser elements adjacent to each other. With optical fiber
With a plurality of first semiconductor laser elements,
A plurality of second semiconductor laser elements corresponding to the plurality of first semiconductor laser elements,
A condensing lens that condenses the laser light emitted from the plurality of first semiconductor laser elements and the laser light emitted from the plurality of second semiconductor laser elements and couples them to the optical fiber.
A photosynthesis unit that synthesizes the laser light emitted from the plurality of first semiconductor laser elements and the laser light emitted from the plurality of second semiconductor laser elements and directs the laser light toward the condenser lens.
An auxiliary mirror that reflects laser light emitted from the plurality of second semiconductor laser elements and directs the laser light toward the photosynthesis unit.
A plurality of first mirrors that reflect the laser light emitted from the corresponding first semiconductor laser element among the plurality of first semiconductor laser elements and direct them toward the photosynthetic unit.
A plurality of second mirrors that reflect the laser beam emitted from the corresponding second semiconductor laser element among the plurality of second semiconductor laser elements and direct them toward the auxiliary mirror.
The plurality of first semiconductor laser elements and a plurality of wavelength stabilizing elements for narrowing the wavelength of the laser light emitted from the plurality of second semiconductor laser elements are provided.
Each of the plurality of wavelength stabilizing elements includes laser light emitted from one or more of the first semiconductor laser elements of the plurality of first semiconductor laser elements, and one or more of the plurality of second semiconductor laser elements. It is configured to narrow the wavelength of the laser light emitted from one or more second semiconductor laser devices corresponding to the first semiconductor laser device of the above.
Laser module. The laser module according to claim 4, wherein the one or more first semiconductor laser elements and the one or more second semiconductor laser elements are arranged at the same height. A plurality of first collimating lenses that collimate the laser light emitted from the corresponding first semiconductor laser element among the plurality of first semiconductor laser elements, and a plurality of first collimating lenses.
A plurality of second collimating lenses that collimate the laser light emitted from the corresponding second semiconductor laser element among the plurality of second semiconductor laser elements are further provided.
Each of the plurality of wavelength stabilizing elements is on the downstream side of the corresponding first collimating lens and the corresponding first mirror in the optical path from the one or more first semiconductor laser elements to the optical fiber. In addition, in the optical path from the one or more second semiconductor laser elements to the optical fiber, the second collimating lens and the corresponding second mirror are arranged on the downstream side.
The laser module according to claim 4 or 5. The one or more first semiconductor laser elements are two or more first semiconductor laser elements adjacent to each other.
The one or more second semiconductor laser elements are two or more second semiconductor laser elements adjacent to each other.
The laser module according to any one of claims 4 to 6. An excitation light source including the laser module according to any one of claims 1 to 7.
A fiber laser apparatus comprising an optical fiber for amplification connected to the optical fiber of the laser module and having a core to which rare earth element ions are added.

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