JP7479348B2 - Optical fiber end structure and semiconductor laser module - Google Patents

Description

The present invention relates to an end structure of an optical fiber and a semiconductor laser module.

A configuration has been disclosed in which laser light output from each of a plurality of semiconductor laser elements is focused and input to one end face of a multimode optical fiber, and output from the other end face (see Patent Document 1). A rectangular glass member is fused to the other end face. Such a glass member is also called an end cap. The end cap has a function of reducing the power density of the output laser light at the interface between the glass and air.

Meanwhile, semiconductor laser modules are also used in industrial fields such as machining and welding. In a semiconductor laser module, a configuration is disclosed in which laser light output from a plurality of semiconductor laser elements is focused and input to one end face of an optical fiber, and propagates through the optical fiber (see Patent Document 2).

JP 2004-128058 A International Publication No. 2015/037725

A technique is conceivable in which an end cap is provided on the end face of an optical fiber where laser light is input, and the power density of the laser light at the interface between glass and air is reduced to be lower than the power density at the interface when the laser light is directly input to the end face of the optical fiber, thereby suppressing the occurrence of damage to the end face of the optical fiber. However, in this case, there may be uncoupled light that is not coupled to the optical fiber among the light input to the end cap. If such uncoupled light reaches another member, it may damage the member. For example, if the uncoupled light reaches a fixing material that fixes the optical fiber to the fixing member, it may damage the fixing material. Also, if the uncoupled light reaches the coating of the optical fiber, it may damage the coating.

The present invention has been made in view of the above, and an object of the present invention is to provide an end structure of an optical fiber and a semiconductor laser module in which the occurrence of damage is suppressed.

In order to solve the above-mentioned problems and achieve the object, an end structure of an optical fiber according to one embodiment of the present invention comprises an optical fiber having a core portion and a cladding portion formed on the outer periphery of the core portion, and an end cap having a first surface joined to an end face of the optical fiber and having a larger area than the end face of the optical fiber, and a second surface located opposite the first surface and having a larger area than the end face of the optical fiber, wherein light is input from the second surface, and is characterized in that an optical processing material is provided in at least a portion of the area of the first surface surrounding the area where the end face of the optical fiber is joined, which scatters or reflects light input to the end cap that is not coupled to the optical fiber.

In an end structure of an optical fiber according to one aspect of the present invention, the light treatment material includes an inorganic adhesive, or a metal film or a dielectric multilayer film that reflects light.

In an end structure of an optical fiber according to one aspect of the present invention, the optical treatment material contains a resin agent that scatters the light.

The end structure of an optical fiber according to one embodiment of the present invention is characterized in that it further comprises a light absorber that is arranged on a portion of the end face side of the optical fiber and on the outer periphery of the end cap, and fixes at least the optical fiber.

An end structure of an optical fiber according to one aspect of the present invention is characterized in that the optical fiber and the end cap are fusion spliced.

An end structure of an optical fiber according to one aspect of the present invention is characterized in that the optical fiber has a thickened portion in which a part of the cladding portion in a longitudinal direction is thickened.

A semiconductor laser module according to one aspect of the present invention is characterized in that it comprises an end structure in the optical fiber, a semiconductor laser element that outputs laser light, and an optical system that focuses the laser light and inputs it to the second surface of the end cap of the end structure.

According to the present invention, it is possible to realize an end structure of an optical fiber and a semiconductor laser module in which the occurrence of damage is suppressed.

FIG. 1 is a schematic plan view of a semiconductor laser module having an end structure according to a first embodiment. FIG. 2 is a schematic, partially cutaway view of the end structure according to the first embodiment. FIG. 3 is a diagram for explaining the state of light input in the end structure. FIG. 4 is a schematic, partially cutaway view of an end structure according to the second embodiment. FIG. 5 is a schematic, partially cutaway view of an end structure according to the third embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described below. In addition, in the description of the drawings, the same or corresponding elements are appropriately given the same reference numerals, and duplicated explanations are appropriately omitted. It should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, etc. may differ from reality.

(Embodiment 1)
1 is a schematic plan view of a semiconductor laser module having an end structure in an optical fiber according to embodiment 1. In the following, the end structure in an optical fiber may be simply referred to as an end structure.

The semiconductor laser module 100 includes a package 101, which is a housing, an LD height adjustment plate 102, submounts 103-1 to 103-6, and six semiconductor laser elements 104-1 to 104-6, which are stacked in order inside the package 101. The package 101 includes a lid, which is not shown in FIG. 1 for the sake of explanation. The semiconductor laser module 100 includes a lead pin 105 for injecting a current into the semiconductor laser elements 104-1 to 104-6. The semiconductor laser module 100 includes first lenses 106-1 to 106-6, second lenses 107-1 to 107-6, mirrors 108-1 to 108-6, a third lens 109, an optical filter 110, and a fourth lens 111, which are optical elements arranged in order on the optical path of the laser light output by the semiconductor laser elements 104-1 to 104-6. The first lenses 106-1 to 106-6, the second lenses 107-1 to 107-6, the mirrors 108-1 to 108-6, the third lens 109, the optical filter 110, and the fourth lens 111 are each fixed inside the package 101. Furthermore, the semiconductor laser module 100 includes an end structure 10 disposed in the vicinity of the fourth lens 111. The end structure 10 includes an optical fiber 11. One end of the optical fiber 11 opposite to the fourth lens 111 side extends to the outside of the package 101.

The semiconductor laser elements 104-1 to 104-6 are arranged at different heights from the bottom surface of the package 101 by the LD height adjustment plate 102. Furthermore, the first lenses 106-1 to 106-6, the second lenses 107-1 to 107-6, and the mirrors 108-1 to 108-6 are arranged at the same height as their corresponding semiconductor laser elements. A loose tube 114 is provided at the insertion portion of the optical fiber 112 into the package 101, and a boot 113 is fitted onto a part of the package 101 so as to cover a part of the loose tube 114.

Each of the semiconductor laser elements 104-1 to 104-6 receives power from the lead pin 105 and outputs a laser beam. The output laser beam is converted into a substantially parallel beam by the first lenses 106-1 to 106-6 and the second lenses 107-1 to 107-6, respectively. Next, each laser beam is reflected in the direction of the optical fiber 112 by one of the mirrors 108-1 to 108-6 arranged at a corresponding height. Then, each laser beam is focused by the third lens 109 and the fourth lens 111. That is, the first lenses 106-1 to 106-6, the second lenses 107-1 to 107-6, the mirrors 108-1 to 108-6, the third lens 109, and the fourth lens 111 constitute an optical system that inputs each laser beam to the end structure 10.

The laser beams focused by the fourth lens 111 are input to the end structure 10. The optical fiber 11 guides the input laser beams and outputs them to the outside of the semiconductor laser module 100.

Next, a more detailed description will be given of each component of the semiconductor laser module 100. The package 101, which is the housing, is preferably made of a material with good thermal conductivity in order to suppress an increase in the internal temperature, and may be a metallic member made of various metals.

As described above, the LD height adjustment plate 102 is fixed inside the package 101 and adjusts the heights of the semiconductor laser elements 104-1 to 104-6 so that the optical paths of the laser beams output by the semiconductor laser elements 104-1 to 104-6 do not interfere with each other. The LD height adjustment plate 102 may be formed integrally with the package 101.

The submounts 103-1 to 103-6 are fixed on the LD height adjustment plate 102 and assist in dissipating heat from the semiconductor laser elements 104-1 to 104-6 placed thereon. For this reason, the submounts 103-1 to 103-6 are preferably made of a material with good thermal conductivity, and may be metallic members made of various metals.

The semiconductor laser elements 104-1 to 104-6 are high-output semiconductor laser elements that output laser light with an intensity of 1 W or more, or even 10 W or more. In this embodiment, the intensity of the laser light output by the semiconductor laser elements 104-1 to 104-6 is, for example, 11 W. The semiconductor laser elements 104-1 to 104-6 output laser light with a wavelength of, for example, 900 nm to 1000 nm. However, the wavelength and intensity of the laser light are not particularly limited. Although the semiconductor laser module 100 includes six semiconductor laser elements 104-1 to 104-6, the number may be a number other than six, or may be just one.

The lead pins 105 supply power to the semiconductor laser elements 104-1 to 104-6 via bonding wires (not shown). The power to be supplied may be a constant voltage, or may be a modulated voltage.

The first lenses 106-1 to 106-6 are cylindrical lenses having a focal length of, for example, 0.3 mm, and are disposed at positions such that the output light of a corresponding one of the semiconductor laser elements is made into substantially parallel light in the vertical direction.

The second lenses 107-1 to 107-6 are cylindrical lenses having a focal length of, for example, 5 mm, and are disposed at positions that convert the output light of the semiconductor laser element into substantially parallel light in the horizontal direction.

The mirrors 108-1 to 108-6 may be mirrors having various metal films or dielectric films, and the higher the reflectivity at the wavelength of the laser light output from the semiconductor laser elements 104-1 to 104-6, the more preferable. Furthermore, the mirrors 108-1 to 108-6 can finely adjust the reflection direction so as to suitably couple the laser light of the corresponding semiconductor laser element to the optical fiber 112.

The third lens 109 and the fourth lens 111 are cylindrical lenses having, for example, focal lengths of 12 mm and 5 mm, respectively, and having mutually orthogonal curvatures, and focus the laser light output from the semiconductor laser elements 104-1 to 104-6 and suitably couple it to the optical fiber 112. The positions of the third lens 109 and the fourth lens 111 with respect to the optical fiber 112 are adjusted, for example, so that the coupling efficiency of the laser light output from the semiconductor laser elements 104-1 to 104-6 to the optical fiber 112 is 85% or more.

The optical filter 110 is a low-pass filter that reflects light with wavelengths of, for example, 1060 nm to 1080 nm and transmits light with wavelengths of 900 nm to 1000 nm. As a result, the optical filter 110 transmits the laser light output from the semiconductor laser elements 104-1 to 104-6 and prevents light with wavelengths of 1060 nm to 1080 nm from being externally irradiated onto the semiconductor laser elements 104-1 to 104-6. The optical filter 110 is disposed at an angle to the optical axis of the laser light so that the output laser light of the semiconductor laser elements 104-1 to 104-6 slightly reflected by the optical filter 110 does not return to the semiconductor laser elements 104-1 to 104-6. The passing wavelength of the optical filter 110 is set to 1060 nm to 1080 nm, but is not limited to this wavelength. The optical filter 110 is not necessarily required.

The boot 113 has the optical fiber 112 inserted therethrough, and prevents damage to the optical fiber 112 due to bending. The boot 113 may be a metal boot, but the material is not particularly limited and may be rubber, various resins, plastics, etc. However, the boot 113 is not necessarily required.

The loose tube 114 has the optical fiber 11 inserted therethrough and prevents damage to the optical fiber 11 due to bending. Furthermore, the loose tube 114 may be fixed to the optical fiber 11, thereby preventing the optical fiber 11 from shifting out of position when a pulling force is applied to the optical fiber 11 in the longitudinal direction. However, the loose tube 114 is not necessarily required.

(Configuration of end structure)
Next, a specific description will be given of the configuration of the end structure 10. FIG.

The end structure 10 includes an optical fiber 11 , an end cap 12 , a light absorber 13 , and an adhesive 14 .

The optical fiber 11 is an optical fiber made of a silica glass material, and has a core 11a, a cladding 11b formed on the outer periphery of the core 11a, and a coating 11c made of resin formed on the outer periphery of the cladding 11b. The optical fiber 11 also has an end face 11d. The coating 11c is removed near the end face 11d, exposing the cladding 11b. The optical fiber 11 may be a multimode optical fiber with a core diameter of the core 11a of 105 μm and a cladding diameter of the cladding 11b of 125 μm, but may also be a single mode optical fiber. The NA of the optical fiber 11 is, for example, 0.15 to 0.22.

The end cap 12 includes an output section 12a having a truncated cone shape and an input section 12b having a cylindrical shape. The output section 12a has a circular bottom surface 12aa, which is the upper bottom surface of the truncated cone shape, and a side surface 12ab, which is the side surface of the truncated cone, as its surface. The bottom surface 12aa of the end cap 12 is joined to the end surface 11d of the optical fiber 11. The joining may be a joining by fusion splicing, or the bottom surface 12aa and the end surface 11d may simply be in contact without being fused. The bottom surface 12aa corresponds to the first surface and has a larger area than the end surface 11d. The output section 12a of the end cap 12 has a diameter that decreases toward the bottom surface 12aa, making it easy to fusion splice with the optical fiber 11.

The input portion 12b has, as its surfaces, a circular toric surface 12ba which is one end face of the cylindrical shape, a side surface 12bb which is a side surface of the cylindrical shape, and a circular bottom surface 12bc which is the other end face of the cylindrical shape. The bottom surface 12bc corresponds to a second surface located opposite to the bottom surface 12aa, and has an area larger than that of the end face 11d.

The material of the end cap 12 is preferably a material having a refractive index similar to that of the core portion 11 a of the optical fiber 11 , and is preferably, for example, the same silica-based glass material as that of the core portion 11 a of the optical fiber 11 .

The end cap 12 receives the laser light L1 condensed by the fourth lens 111 from a bottom surface 12bc.

The light absorber 13 is a cylindrical member and is disposed on a part of the end face 11d side of the optical fiber 11 and on the outer periphery of the end cap 12. The light absorber 13 has an insertion hole 13a in which the optical fiber 11 is disposed, and a recess 13b that communicates with the insertion hole 13a and in which the end cap 12 is disposed. The light absorber 13 is fixed to the cladding portion 11b by a fixing material 14. The light absorber 13 may be composed of a single cylindrical member, or may be composed of a combination of multiple members. In addition, the shape of the light absorber 13 is not particularly limited, and the outer edge is, for example, circular or polygonal in a cross section perpendicular to the insertion hole 13a. In addition, the cross-sectional shape of the insertion hole 13a is also not particularly limited, and may be circular or polygonal. The outer edge may be polygonal and the insertion hole 13a may be circular.

The light absorber 13 has light absorption at the wavelength of the laser light L1, and has an absorptivity of 30% or more, preferably 70% or more, at the wavelength of the laser light L1. As a result, the light absorber 13 absorbs the laser light leaked from the cladding portion 11b of the laser light L1 input to the optical fiber 11. In addition, the light absorber 13 is preferably made of a material with good thermal conductivity in order to dissipate heat generated by light absorption, and is preferably made of, for example, a metal member containing Cu, Ni, stainless steel, or Fe, a metal containing Ni, Cr, Ti, or a member having a surface plating layer containing C, a ceramic member containing AlN or Al ₂ O ₃ , or a member having a ceramic layer covering the surface containing AlN or Al ₂ O _3. In addition, the light absorber 13 is preferably connected to the package 101 via a good thermal conductor (not shown) in order to dissipate heat generated by light absorption. The good thermal conductor is preferably made of a material with a thermal conductivity of 0.5 W/mK or more, and is, for example, made of solder or a thermally conductive adhesive.

The fixing material 14 is made of a UV-curable resin such as an epoxy resin or a urethane-based resin. The refractive index of the fixing material 14 is preferably equal to or higher than the refractive index of the cladding portion 11b of the optical fiber 11 at 25° C., and more preferably equal to or higher than the refractive index of the cladding portion 11b of the optical fiber 11 in the operating temperature range of the semiconductor laser module 100 (for example, 15° C. to 100° C.). The refractive index of the fixing material 14 is, for example, a relative refractive index difference with respect to the cladding portion 11b of the optical fiber 11 of 0% to 10%. In addition, the fixing material 14 preferably has a thickness of 1 μm to 800 μm in the direction perpendicular to the longitudinal direction of the optical fiber 11. It is known that the refractive index of the UV-curable resin can be reduced by, for example, containing fluorine, and can be increased by, for example, containing sulfur, and the refractive index can be adjusted by adjusting the content of a material that increases or decreases the refractive index.

Next, a more specific configuration of the end cap 12 and the input state of the laser light L1 will be described with reference to Fig. 3. In Fig. 3, laser light L1a, L1b, and L1c are components of the laser light L1.

An AR (Anti-Reflection) coating 12c is provided on a bottom surface 12bc of the end cap 12. This suppresses reflection of the laser beams L1a, L1b, and L1c on the bottom surface 12bc.

The bottom surface 12bc of the end cap 12 has a larger area than the end surface 11d of the optical fiber 11. As a result, when the laser light L1 is condensed and input to the end structure 10, the power density of the beam of the laser light L1 at the interface is smaller when input to the bottom surface 12bc of the end cap 12 than when input directly to the end surface 11d of the optical fiber 11. As a result, the occurrence of damage to the glass due to the power of the laser light L1 is suppressed.

Furthermore, an optical processing material 12d is provided in an annular region of the side surface 12ab, the annular surface 12ba, and the bottom surface 12aa of the end cap 12 that surrounds the region where the end surface 11d of the optical fiber 11 is joined.

The laser light L1 includes a laser light L1a that is a component that is coupled to the core 11a of the optical fiber 11 and propagates through the core 11a. The laser light L1 also includes a laser light L1b that is not coupled to the core 11a of the optical fiber 11 but is coupled to the cladding 11b and propagates in a cladding mode. The laser light L1b propagating in the cladding mode gradually leaks out in the longitudinal direction, passes through the fixing material 14, and is absorbed by the light absorber 13.

Furthermore, the laser light L1 includes a component that is not coupled to the optical fiber 11, that is, a laser light L1c that is a non-coupled light. The laser light L1c reaches, for example, an annular region of the bottom surface 12aa that surrounds the region where the end surface 11d is joined.

The light treatment material 12d scatters or reflects the laser light L1c, which prevents the laser light L1c from reaching the adhesive 14 or the coating 11c, or in the case of scattered light, the light density is low even if the laser light L1c reaches the adhesive 14 or the coating 11c, so that damage to the adhesive 14 or the coating 11c is suppressed.

The light processing material 12d is not particularly limited as long as it scatters or reflects the laser light L1c. For example, the light processing material 12d is a high-reflection coating made of a dielectric multilayer film or a metal film. The reflectance of the high-reflection coating is preferably 80% or more, and more preferably 95% or more.

For example, the light processing material 12d contains an inorganic adhesive as a main component. The light processing material 12d may also be made of an inorganic adhesive. The inorganic adhesive is, for example, a silicon-based or alumina-based adhesive, and becomes a ceramic film when applied in an uncured state and then cured. The inorganic adhesive reflects or scatters light. The inorganic adhesive is preferable because it has high heat resistance. In addition, when the inorganic adhesive uses an organic solvent, most of the organic solvent volatilizes during curing.

For example, the light processing material 12d contains a resin agent that scatters the laser light L1c as a main component. The light processing material 12d may also be made of a resin agent that scatters the laser light L1c. For example, a silicone-based thermally conductive compound can be used as such a resin. Such a thermally conductive compound contains, for example, boron nitride as a filler, and the filler scatters and diffuses the light. Such a thermally conductive compound contains, for example, boron nitride as a filler, and is, for example, T644 manufactured by Comerics, Inc., USA. Also, the filler that scatters the light is not limited to boron nitride, and may be other inorganic fillers.

Furthermore, if the light processing material 12d contains an inorganic adhesive or a resin agent, the light processing material 12d can be easily and inexpensively formed by applying and curing the material after fusion splicing the optical fiber 11 and the end cap 12. Furthermore, the light processing material 12d can be easily provided so that no gap is formed between the optical fiber 11 and the light processing material 12d.

In this embodiment, the light treatment material 12d is provided on the side surface 12ab, the annular surface 12ba, and the annular region of the bottom surface 12aa of the end cap 12. However, the light treatment material may be provided, for example, only on the annular region of the bottom surface 12aa or a part of the region, or on the annular region of the bottom surface 12aa and the side surface 12ab or a part of the side surface 12ab of the end cap 12.

As described above, in the end structure 10, damage to the adhesive 14 and the coating 11c is suppressed.

(Embodiment 2)
4 is a schematic, partially cutaway view of an end structure 10A according to embodiment 2. This end structure 10A can be used in place of the end structure 10 in the semiconductor laser module 100.

The end structure 10A includes an optical fiber 11, an end cap 12A, a light absorber 13A, a fixing material 14, and a light treatment material 12Ad.

The end cap 12A has a configuration in which the light treatment material 12d is deleted from the configuration of the end cap 12 shown in Fig. 3. The light absorber 13A has a configuration in which an injection hole 13c is further provided in addition to the configuration of the light absorber 13 shown in Fig. 2. The injection hole 13c is formed so as to communicate from the outer peripheral surface of the light absorber 13 to the recess 13b. The light absorber 13A may be composed of a single cylindrical member, or may be composed of a combination of multiple members. The fixing material 14 fixes the cladding portion 11b of the optical fiber 11 and the light absorber 13A, as in Fig. 2.

In the end structure 10A, the recess 13b of the light absorber 13A is filled with the light processing material 12Ad. As a result, the light processing material 12Ad is provided in the side surface 12ab, the annular surface 12ba, and the annular area around the area of the bottom surface 12aa of the end cap 12A where the end surface 11d of the optical fiber 11 is joined. As a result, in the end structure 10A, as in the case of the end structure 10, the light processing material 12Ad scatters or reflects non-coupled light that is not coupled to the optical fiber 11 out of the laser light L1 input from the bottom surface 12bc of the end cap 12A. As a result, damage to the fixing material 14 and the coating 11c is suppressed.

The light treatment material 12Ad may be, for example, a material containing an inorganic adhesive as a main component, or a resin agent that scatters uncoupled light, and may be the same as the light treatment material 12d. The light treatment material 12Ad can be filled into the recess 13b by injecting it in an uncured state through the injection hole 13c and then curing it.

In this embodiment, the optical treatment material 12Ad may be provided, for example, in a circular region of the bottom surface 12aa or only in a part of the region, or may be provided in a circular region of the bottom surface 12aa and in the side surface 12ab or a part of the side surface 12ab of the end cap 12. However, the region in which the optical treatment material 12Ad is provided is not limited to these.

(Embodiment 3)
5 is a schematic, partially cutaway view of an end structure 10B according to embodiment 2. This end structure 10A can be used in place of the end structure 10 in the semiconductor laser module 100.

The end structure 10B includes an optical fiber 11B, an end cap 12, a light absorber 13B, and an adhesive 14.

The optical fiber 11B has a configuration in which the cladding portion 11b of the optical fiber 11 is replaced with the cladding portion 11Bb. The optical fiber 11B has a thickened portion 11Bba in which a portion of the cladding portion 11Bb in the longitudinal direction is thickened. The thickened portion 11Bba has a cladding diameter that is the same as that of the portion other than the thickened portion 11Bba at the end face 11Bd of the optical fiber 11B, and is, for example, 125 μm. The thickened portion 11Bba is composed of a portion in which the cladding diameter increases in a tapered manner as it moves away from the end face 11Bd, a portion in which the cladding diameter is a constant thick diameter, and a portion in which the cladding diameter decreases in a tapered manner as it moves away from the end face 11Bd. The cladding diameter after the diameter reduction is, for example, 125 μm. The cladding diameter of the constant thick diameter portion is larger than 125 μm, and is, for example, 500 μm.

The light absorber 13B, like the light absorber 13, has an insertion hole 13Ba in which the optical fiber 11B is disposed, and a recess 13b that communicates with the insertion hole 13Ba and in which the end cap 12 is disposed. The inner diameter of the insertion hole 13Ba corresponds to the cladding diameter of the thick-diameter portion 11Bba of the optical fiber 11B. The light absorber 13B is fixed to the thick-diameter portion 11Bba of the cladding portion 11Bb with a fixing material 14.

The end cap 12 is provided with a light processing material 12d (not shown in FIG. 5) similar to the end cap shown in FIG.

In the end structure 10B, as in the end structures 10 and 10A, damage to the adhesive 14 and the coating 11c is suppressed.

Furthermore, in the end structure 10B, when the laser light propagating in the cladding mode (for example, the laser light L1b in FIG. 2) reaches the outer peripheral surface of the large diameter portion 11Bba and leaks out and passes through the adhesive 14, the power density of the laser light is reduced compared to when the large diameter portion 11Bba is not present. As a result, the occurrence of damage to the adhesive 14 can be further suppressed.

In this embodiment, the large diameter portion 11Bba starts from the end face 11d of the optical fiber 11, but the large diameter portion 11Bba may be spaced apart from the end face 11d. In this embodiment, both ends of the large diameter portion 11Bba are tapered, but at least one of the ends may be stepped.

In the above embodiment, the end caps 12, 12A have a shape that combines a cylindrical shape with a truncated cone shape, but the shape of the end caps is not limited to this and may be, for example, a rectangular parallelepiped shape or a cylindrical shape.

In the above embodiment, the laser light having a wavelength in the infrared region is taken as an example, but the wavelength is not limited to this. For example, in the case of a laser light having a short wavelength such as green or blue, the amount of energy absorbed by the adhesive is larger than that of a laser light having a wavelength in the infrared region, and the effect of the present invention may be more pronounced.

Furthermore, the present invention is not limited to the above-mentioned embodiment. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible.

The present invention can be applied to optical fibers and semiconductor laser modules.

10, 10A, 10B End structure 11, 11B Optical fiber 11a Core portion 11b, 11Bb Cladding portion 11Bba Large diameter portion 11c Coating 11d, 11Bd End face 12, 12A End cap 12a Output portion 12aa Bottom surface 12ab Side surface 12b Input portion 12ba Annular surface 12bb Side surface 12bc Bottom surface 12c AR coating 12d, 12Ad Light processing material 13, 13A, 13B Light absorber 13a, 13Ba Insertion hole 13b Recess 13c Injection hole 14 Fixing material 100 Semiconductor laser module 101 Package 102 LD height adjustment plate 103-1 to 103-6 Submount 104-1 to 104-6 Semiconductor laser element 105 Lead pin 106-1 to 106-6 First lenses 107-1 to 107-6 Second lenses 108-1 to 108-6 Mirror 109 Third lens 110 Optical filter 111 Fourth lens 112 Optical fiber 113 Boot 114 Loose tubes L1, L1a, L1b, L1c Laser light

Claims (9)

an optical fiber having a core portion and a cladding portion formed on the outer periphery of the core portion;
an end cap having a first surface joined to an end surface of the optical fiber and having an area larger than that of the end surface of the optical fiber, and a second surface located on the opposite side to the first surface and having an area larger than that of the end surface of the optical fiber, wherein light is input from the second surface;
Equipped with
the light input to the end cap includes a component that is not coupled to the optical fiber;
An end structure for an optical fiber, characterized in that an optical processing material that scatters or reflects components that are not coupled to the optical fiber is provided in an annular region of the first surface surrounding the area where the end face of the optical fiber is joined. The end cap is
an input portion having the second surface and a toric surface located away from the second surface toward the optical fiber, the input portion having a cylindrical shape extending between the second surface and the toric surface;
an output section having a truncated cone shape that protrudes from an inner side of the annulus of the annular surface toward the optical fiber in a tapered manner, the output section having the first surface and a side surface of the truncated cone shape;
having
2. The end structure of an optical fiber according to claim 1, further comprising a light processing material provided on said annular surface and said side surface for scattering or reflecting components not coupled to said optical fiber. 3. The end structure of an optical fiber according to claim 1, wherein the optical treatment material includes an inorganic adhesive, or a metal film or a dielectric multilayer film that reflects light. 3. The end structure of an optical fiber according to claim 1, wherein the light processing material contains a resin agent that scatters the light. The end structure of an optical fiber described in any one of claims 1 to 4 , further comprising a light absorber arranged on a portion of the end face side of the optical fiber and on the outer periphery of the end cap, and fixing at least the optical fiber. 6. The end structure of an optical fiber according to claim 1, wherein the optical fiber and the end cap are fusion spliced. 7. The end structure of an optical fiber according to claim 1 , wherein the optical fiber has a thickened portion in a longitudinal direction of the cladding. An end structure of an optical fiber according to any one of claims 1 to 7 ;
a semiconductor laser element that outputs laser light;
an optical system for focusing the laser light onto the second surface of the end cap of the end structure;
A semiconductor laser module comprising: an optical fiber having a core portion and a cladding portion formed on the outer periphery of the core portion;
an end cap having a first surface joined to an end surface of the optical fiber and having an area larger than that of the end surface of the optical fiber, and a second surface located on the opposite side to the first surface and having an area larger than that of the end surface of the optical fiber, wherein light is input from the second surface;
Equipped with
the light input to the end cap includes a component that is not coupled to the optical fiber;
a light processing material that scatters or reflects components that are not coupled to the optical fiber is provided on at least a part of a region of the first surface surrounding a region to which the end face of the optical fiber is joined;
a light absorber disposed on a portion of the end face side of the optical fiber and on an outer periphery of the end cap, and fixing at least the optical fiber;
an optical fiber end structure, characterized in that the cladding portion and the optical absorber are fixed to each other by an adhesive interposed between the cladding portion and the optical absorber in a state of contact with the cladding portion and the optical absorber.

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