JP2004045667A - Fiber module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive multiplex laser light source capable of obtaining high output. <P>SOLUTION: After laser beams B1-B7 respectively emitted from a plurality of semiconductor lasers LD1-LD7 are converged by a converging optical system composed of collimator lenses 11-17 and a converging lens 20 for instance, they are coupled to a multi-mode optical fiber 30 and multiplexed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fiber module including a light source and an optical fiber into which light emitted from the light source is incident.
[0002]
[Prior art]
Conventionally, wavelength conversion lasers, excimer lasers, and Ar lasers that convert infrared light emitted from semiconductor laser-excited solid-state lasers into third harmonics in the ultraviolet region have been put to practical use as devices that generate ultraviolet laser beams. It is provided.
[0003]
Furthermore, recently, for example, Jpn. Appl. phys. Lett. , Vol. 37. p. As shown in L1020, a GaN-based semiconductor laser that emits a laser beam having a wavelength near 400 nm is also provided.
[0004]
A light source that emits a laser beam having such a wavelength is used as an exposure light source in an exposure apparatus that exposes a photosensitive material having sensitivity in a predetermined wavelength region (hereinafter referred to as “ultraviolet region”) including an ultraviolet region of 350 to 420 nm. It is also considered to apply. In this case, the light source for exposure is naturally required to have a sufficient output for exposing the photosensitive material.
[0005]
However, the excimer laser has a problem that the apparatus is large, and the cost and maintenance cost are high.
[0006]
In addition, a wavelength conversion laser that converts infrared light into the third harmonic in the ultraviolet region has extremely low wavelength conversion efficiency, so that it is extremely difficult to obtain a high output. At present, a solid laser medium is excited with a 30 W semiconductor laser to oscillate a 10 W fundamental wave (wavelength 1064 nm), which is converted into a 3 W second harmonic (wavelength 532 nm), and the sum frequency of both of them. The current practical level is to obtain a third harmonic of 1 W (wavelength 355 nm). In this case, the electro-optical efficiency of the semiconductor laser is about 50%, and the conversion efficiency to ultraviolet light is very low, about 1.7%. Such a wavelength conversion laser is considerably expensive because it uses an expensive optical wavelength conversion element.
[0007]
In addition, the Ar laser has a problem that the electro-optical efficiency is very low as 0.005% and the lifetime is as short as about 1000 hours.
[0008]
On the other hand, since a low dislocation GaN crystal substrate cannot be obtained for a GaN-based semiconductor laser, a low dislocation region of about 5 μm is created by a growth method called ELOG, and a laser region is formed thereon to increase the output. Attempts have been made to achieve high reliability. However, even in the GaN-based semiconductor laser manufactured in this way, it is difficult to obtain a substrate with a low dislocation over a large area, so that a high output of 500 mW to 1 W class has not yet been commercialized.
[0009]
As another attempt to increase the output power of a semiconductor laser, for example, it may be possible to obtain 10 W output by forming 100 cavities that output 100 mW light by one. It can be said that creating a large number of cavities at a high yield is almost unrealistic. This is especially true for GaN-based semiconductor lasers where it is difficult to achieve a high yield of 99% or more even in the case of a single cavity.
[0010]
In view of the above circumstances, the present applicant has previously proposed a low-cost combined laser light source capable of obtaining a high output (Japanese Patent Application No. 2001-274349). The combined laser light source disclosed in Japanese Patent Application No. 2001-274349 is composed of a plurality of semiconductor lasers, a single multimode optical fiber, and a laser beam emitted from each of the plurality of semiconductor lasers, and then focused on the multimode optical fiber. And a condensing optical system to be coupled.
[0011]
[Problems to be solved by the invention]
In the above-described combined laser light source, a semiconductor laser and a condensing optical system are housed in a package, and one end portion of an optical fiber is also housed in the package to constitute a fiber module. In such a fiber module, one end of the optical fiber is fixed to a fiber holder or a bracket fixed inside the package. Conventionally, this optical fiber is fixed by YAG welding of an optical fiber with a metal tube (ferrule). It has been made by using a method of fixing with brazing material.
[0012]
However, the fixing accuracy of the optical fiber is ± 1 to 5 μm when YAG welding is performed, and ± 5 to several tens μm when fixing with brazing material. Therefore, the optical fiber is accurately aligned with respect to the convergence position of the laser beam. Therefore, the coupling efficiency between the two is only about 80% in the former case and about 60 to 80% in the latter case. Conventionally, the optical fiber is also fixed with an adhesive, but the fixing accuracy of the optical fiber in that case is the same as described above.
[0013]
This invention is made | formed in view of said situation, and it aims at providing the fiber module which can improve the coupling efficiency of incident light and an optical fiber.
[0014]
[Means for Solving the Problems]
As described above, the fiber module according to the present invention includes an optical fiber, a holding member that holds one end of the optical fiber, a light source, and an optical system that causes the light emitted from the light source to enter the optical fiber from one end surface thereof. The fiber module is characterized in that the optical fiber is bonded and fixed to the holding member with a thinned ultraviolet curable adhesive. The thickness of the ultraviolet curable adhesive is desirably 1 μm or less.
[0015]
On the other hand, in the fiber module of the present invention having the above-described configuration, the holding member is preferably formed of a transparent member.
[0016]
Further, the present invention provides a plurality of semiconductor lasers, one multimode optical fiber, and laser beams respectively emitted from the plurality of semiconductor lasers, as in the combined laser light source of Japanese Patent Application No. 2001-274349 described above. It is desirable to be applied to a combined laser device including a condensing optical system that condenses and couples to a multimode optical fiber.
[0017]
In this case, a plurality of semiconductor lasers are arranged so that the light emitting points are arranged in a line in a direction parallel to each active layer, and the condensing optical system has an aperture diameter in the direction in which the light emitting points are arranged. Is formed smaller than the opening diameter in a direction perpendicular to the direction, and a plurality of collimator lenses provided for each semiconductor laser and a plurality of laser beams collimated by these collimator lenses are collected. It is particularly desirable that it is composed of a condensing lens that converges light and converges at the end face of the multimode optical fiber.
[0018]
The plurality of collimator lenses are preferably integrated with each other to form a lens array.
[0019]
On the other hand, it is desirable that the block on which the plurality of semiconductor lasers are mounted is divided into a plurality of pieces and is bonded together to be integrated.
[0020]
In the case where a plurality of semiconductor lasers are arranged in a line, it is desirable that 3 to 10 semiconductor lasers, more preferably 6 or 7 semiconductor lasers are provided. As this semiconductor laser, it is desirable to use one having a light emission width of 1.5 to 5 μm, more preferably 2 to 3 μm. As this semiconductor laser, a GaN semiconductor laser is preferably used.
[0021]
On the other hand, as the multi-mode optical fiber, it is desirable to use one having a core diameter of 50 μm or less and an NA (numerical aperture) of 0.3 or less. Furthermore, it is desirable to use a multimode optical fiber having a core diameter × NA value of 7.5 μm or less.
[0022]
Further, when the above-described combined laser light source is constituted by the fiber module of the present invention, it is desirable that the plurality of semiconductor lasers are two-dimensionally arranged and fixed as viewed from the side receiving the laser beam irradiation.
[0023]
In this case, the combined laser light source may be configured by using only one multimode optical fiber as described above. Preferably, a plurality of multimode optical fibers are used, and a plurality of multimode optical fibers are used. A combination of a semiconductor laser and a condensing optical system can also be configured to emit a high-power laser beam from each multimode optical fiber. In such a case, it is desirable that the plurality of multimode optical fibers be arranged in a one-dimensional array form or a bundle form at least at the emission end.
[0024]
【The invention's effect】
According to the inventor's research, as described above, sufficient fixing accuracy cannot be obtained in the prior art in which the optical fiber is fixed with adhesive, YAG welding, or brazing material. It was found that the expansion and contraction due to heat occurred when the temperature change was applied.
[0025]
In view of this knowledge, in the fiber module of the present invention, since the optical fiber is bonded and fixed to the holding member with the thinned ultraviolet curable adhesive, when the temperature change is applied to this bonded portion Expansion and contraction can be suppressed to a small extent, and sufficient fixing accuracy can be obtained. Specifically, the coupling efficiency between the incident light and the optical fiber can be increased to 90% or more by making the ultraviolet curable adhesive into a thin layer of about 1 μm or less.
[0026]
In the fiber module of the present invention, when the holding member is made of a transparent member, when the ultraviolet curable adhesive is cured by irradiating with ultraviolet rays, the ultraviolet rays can be prevented from being blocked by the holding member. The irradiation direction of ultraviolet rays can be freely set, thereby realizing good workability.
[0027]
Further, the above-described combined laser light source configured by the fiber module of the present invention has a very simple configuration in which laser beams respectively emitted from a plurality of semiconductor lasers are condensed and coupled to a multimode optical fiber, In particular, since an element that is difficult to manufacture is not required, it can be formed at low cost.
[0028]
In such a combined laser light source, in particular, a plurality of semiconductor lasers are arranged so that the light emitting points are arranged in a line in a direction parallel to each active layer, and a condensing optical system is arranged in the arrangement of the light emitting points. A plurality of collimator lenses provided for each semiconductor laser, and a plurality of lasers collimated by these collimator lenses, having an aperture diameter in a direction smaller than an aperture diameter in a direction perpendicular to the direction In the case of a condensing lens for condensing the beams and converging them at the end face of the multimode optical fiber, the arrangement pitch of the plurality of semiconductor lasers can be made shorter and arranged at a higher density. By arranging a plurality of semiconductor lasers at a higher density in this way, the positional deviation of the plurality of laser beams at the end face of the optical fiber can be suppressed to a smaller level. The effect that the assembly position accuracy of the system can be relatively relaxed can be obtained, and furthermore, since this assembly position accuracy can be relaxed, the number of combined waves can be increased to increase the output. The reason will be described in detail later along the embodiment.
[0029]
In addition, when a plurality of collimator lenses as described above are integrated with each other and configured as a lens array, each lens is compared with a case where a plurality of collimator lenses are formed separately. Since it can be avoided that a large ineffective area is formed in the peripheral portion, the lenses can be arranged closer to each other. If so, since a plurality of semiconductor lasers can be arranged at a higher density, the effect that the above assembly position accuracy can be loosened, and the effect that the number of combined waves can be increased to increase the output is further remarkable. Become.
[0030]
Furthermore, in this case, the collimator lens position adjustment operation is only required to adjust the position of one lens array, and thus this operation is simplified.
[0031]
Also, in the fields of printing and medical images, and when exposing images on photosensitive materials such as PCBs (Printed Circuit Boards), PDPs (Plasma Displays), LCDs (Liquid Crystal Displays), etc., the core is used as the multimode optical fiber. When a diameter of 50 μm or less is used, it becomes possible to expose a high-definition image with a fine exposure spot. Further, when the NA of the multimode optical fiber is 0.3 or less, a sufficient depth of focus is ensured for exposing a high-definition image as described above, and an image with high sharpness can be exposed.
[0032]
Further, when a multimode optical fiber having a core diameter × NA of 7.5 μm or less is used, the combinations thereof are, for example, 50 μm × 0.15, 40 μm × 0.188, 30 μm × 0.25, 25 μm × 0. .3 etc. When a multimode optical fiber having such characteristics is used, a laser beam from each semiconductor laser can be collimated with a collimator lens having the same NA as that NA, and a condensing lens with NA = 0.3 is 25 μm or less. It is also possible to focus the combined laser beam on the spot. As a result, high resolution and a sufficient depth of focus can be ensured.
[0033]
On the other hand, when the block on which the plurality of semiconductor lasers are mounted is divided into a plurality of parts and integrated with each other, the mounting yield is improved as compared with the case where all the semiconductor lasers are mounted on one block. be able to. For example, when the mounting yield of one semiconductor laser is 98%, the total mounting yield when all six semiconductor lasers are mounted in one block is 86% (= 0.98 ⁶ × 100). On the other hand, in the case where three blocks are mounted on two blocks, the yield of joining the two blocks can be almost 100%, so that it is improved to 94% (= 0.98 ³ × 100).
[0034]
In addition, in the combined laser light source as described above, if three or more semiconductor lasers are provided, the conventionally known polarization multiplexing can combine only laser beams from two semiconductor lasers, but it exceeds that. It is possible to obtain a high-power combined beam. However, if the mounting yield of one semiconductor laser is 98% so that it is usually about that level, when 10 semiconductor lasers are provided, the mounting yield decreases to 82%. Since further reduction in yield must be avoided in practice, in the preferred embodiment of the present invention, the upper limit of the number of semiconductor lasers is 10.
[0035]
Further, when 10 semiconductor lasers are arranged in a line, when a multimode optical fiber having a core diameter for image formation of 50 μm or less and NA of 0.3 or less, or core diameter × NA = 7.5 μm or less is used, Although the required mounting accuracy is very severe, less than 0.1 μm, the required mounting accuracy is significantly less than 0.3-1 μm by setting the number of semiconductor lasers arranged in a row to 6 or 7. Alleviated. Further, when the number of semiconductor lasers is 6 or 7, it is possible to obtain a high output more than twice as compared with the case where there are three semiconductor lasers.
[0036]
In addition, by applying a semiconductor laser having a light emission width of 1.5 μm or more, for example, when it is a GaN-based semiconductor laser, compared to the maximum output (about 30 mW) of a complete single transverse mode structure, High output (50 mW or more) can be obtained. On the other hand, by applying a semiconductor laser having a light emission width of 5 μm or less, a semiconductor for a multimode optical fiber having a core diameter for image formation of 50 μm or less and NA of 0.3 or less, or core diameter × NA = 7.5 μm or less. It becomes possible to construct a condensing coupling system having three or more lasers. In addition, by applying a semiconductor laser having a light emission width of 2 to 3 μm, it is possible to configure a 6 or 7 condensing coupling system in the optical system for image formation.
[0037]
If a plurality of semiconductor lasers are two-dimensionally arranged as viewed from the side irradiated with the laser beam, a large number of semiconductor lasers can be arranged at a high density. Can be made incident, and a combined laser beam with higher output can be obtained.
[0038]
On the other hand, when the above combined laser light source has a plurality of multimode optical fibers arranged in a one-dimensional array or bundle at least at the emission end, a high-power laser beam is one-dimensionally transmitted from these optical fibers. Alternatively, it can be emitted in a two-dimensionally aligned state. If so, each of a plurality of laser beams that are aligned and emitted is incident on each modulation unit of a spatial light modulation element such as a GLV or DMD in which the modulation units are arranged in a line or two-dimensional form. , And can be modulated efficiently for image exposure and the like.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0040]
3, 4 and 5 show the planar shape, side shape and partial front shape of the ultraviolet light high-intensity multiplexing fiber module according to the first embodiment of the present invention. 1 and 2 are enlarged views of a part of the fiber module. This fiber module constitutes a combined laser light source as described above.
[0041]
First, as shown in the plan view of FIG. 1, this combined laser light source is an example in which seven multi-chip lateral multimode GaN-based semiconductor lasers LD1, LD2, LD3 are arranged and fixed on a heat block 10 made of copper. LD4, LD5, LD6 and LD7 and collimator lenses 11, 12, 13, 14, 15, 16 and 17 provided for the respective GaN-based semiconductor lasers LD1, LD2, LD3, LD4, LD5, LD6 and LD7, respectively. And one condensing lens 20 and one multimode optical fiber 30.
[0042]
In FIG. 1, the shapes of the collimator lenses 11 to 17 and the condenser lens 20 are schematically shown. Details of the mounting state will be described later. 2 shows how the GaN-based semiconductor lasers LD1 to 7 are attached to the heat block 10. As shown in FIG.
[0043]
The GaN-based semiconductor lasers LD1 to LD7 have a common oscillation wavelength of 405 nm, for example, and a maximum output of 100 mW. Laser beams B1, B2, B3, B4, B5, B6, and B7 emitted in a divergent light state from these GaN-based semiconductor lasers LD1, LD2, LD3, LD4, LD5, LD6, and LD7 are collimator lenses 11, 12 respectively. , 13, 14, 15, 16 and 17 are collimated.
[0044]
The parallel laser beams B1 to B7 are collected by the condenser lens 20 and converge on the incident end face of the core 30a of the multimode optical fiber 30. In this example, the collimating lenses 11 to 17 and the condensing lens 20 constitute a condensing optical system, and the multimode optical fiber 30 constitutes a multiplexing optical system. That is, the laser beams B1 to B7 condensed as described above by the condensing lens 20 are incident on the core 30a of the multimode optical fiber 30 and propagate there, and are combined into one laser beam B to be multiplexed. The light is emitted from the mode optical fiber 30. As the multimode optical fiber 30, a step index type, a graded index type, and a composite type thereof can all be applied.
[0045]
Next, the overall configuration of the ultraviolet light high-intensity multiplexing fiber module will be described in detail with reference to FIGS. 3, 4 and 5 show the planar shape, side shape and partial front shape of the ultraviolet light high-intensity multiplexing fiber module, respectively. In these drawings, the shapes and mounting states of the collimator lenses 11 to 17 and the condenser lens 20 are shown in detail.
[0046]
In this example, the optical elements constituting the module are accommodated in a box-shaped package 40 having an upper opening, and the opening of the package 40 is closed by the package lid 41, whereby the package 40 and the package lid 41 are defined. It is hermetically held in a closed space.
[0047]
A base plate 42 is fixed to the bottom surface of the package 40, the heat block 10 is attached to the top surface of the base plate 42, and a collimator lens holder 44 that holds the collimator lenses 11 to 17 is fixed to the heat block 10. ing. Further, a condensing lens holder 45 that holds the condensing lens 20 and a fiber block 43 are fixed to the upper surface of the base plate 42. A fiber holder 46 that holds the incident end of the multimode optical fiber 30 is fixed to the fiber block 43. Further, the wirings 47 for supplying a driving current to the GaN-based semiconductor lasers LD1 to LD7 are drawn out of the package through openings formed in the lateral wall surface of the package 40.
[0048]
In FIG. 3, in order to avoid complication of the drawing, only one GaN-based semiconductor laser LD 7 among the GaN-based semiconductor lasers LD 1 to 7 is numbered, and similarly, one of the collimator lenses 11 to 17. Only the collimator lens 17 is numbered.
[0049]
FIG. 5 shows the front shape of the mounting portion of the collimator lenses 11-17. As shown here, each of the collimator lenses 11 to 17 has a shape obtained by cutting a region including the optical axis of an aspherical circular lens into an elongated shape, and is formed by molding a resin or optical glass, for example. The 6 (1) and (2) respectively show the enlarged side surface shape and front surface shape of one collimator lens 17 on behalf of them, including the dimensions (unit: mm) of the main part.
[0050]
As shown in FIGS. 5 and 6, the collimator lenses 11 to 17 have directions in which the aperture diameters in the direction in which the light emission points of the GaN-based semiconductor lasers LD1 to LD7 are aligned (the left-right direction in FIG. It is formed smaller than the opening diameter in the vertical direction) and is closely arranged in the direction in which the light emitting points are arranged.
[0051]
On the other hand, the GaN-based semiconductor lasers LD1 to LD7 emit laser beams B1 to B7 having an emission width of 2 μm and divergence angles in a direction parallel to and perpendicular to the active layer, respectively, as 10 ° and 30 °, for example. Things are used. These GaN-based semiconductor lasers LD1 to LD7 are arranged so that the light emitting points are arranged in a line in a direction parallel to the active layer.
[0052]
Therefore, the laser beams B1 to B7 emitted from the respective light emitting points coincide with the direction of the large aperture diameter in the direction of the maximum divergence angle with respect to the respective collimator lenses 11 to 17 having the elongated shape as described above. The incident light is incident in a state where the direction with the smallest divergence angle coincides with the direction in which the aperture diameter is small. That is, each of the collimator lenses 11 to 17 having a long and narrow shape is used with the ineffective portion as small as possible corresponding to the elliptical cross-sectional shape of the incident laser beams B1 to B7. Specifically, in this embodiment, the aperture diameters of the collimator lenses 11 to 17 are 1.1 mm and 4.6 mm in the horizontal direction and the vertical direction, respectively, and the horizontal and vertical directions of the laser beams B1 to 7 incident thereon. The direction beam diameters are 0.9 mm and 2.6 mm, respectively. Further, the focal lengths f ₁ of the collimator lenses 11 to 17 are 3 mm, NA is 0.6, and the lens arrangement pitch is 1.25 mm.
[0053]
Further, (1) and (2) in FIG. 7 show the enlarged side surface shape and front surface shape of the condenser lens 20, respectively, including the dimensions (unit: mm) of the main part. As shown here, the condensing lens 20 also has a shape in which the region including the optical axis of the aspherical circular lens is cut into an elongated shape and is long in the alignment direction of the collimator lenses 11 to 17, that is, in the horizontal direction, and short in the direction perpendicular thereto. Has been. The focal length f _{2 of the} condenser lens 20 is 12.5 mm, and NA = 0.3. The condensing lens 20 is also formed by molding resin or optical glass, for example.
[0054]
On the other hand, the multimode optical fiber 30 is based on a graded index type optical fiber manufactured by Mitsubishi Cable Industries, Ltd., the core center portion is a graded index and the outer peripheral portion is a step index. Core diameter = 25 μm, NA = 0. 3. The transmittance of the end coat is 99.5% or more. In the case of this example, the value of the core diameter × NA described above is 7.5 μm.
[0055]
In the configuration of the present embodiment, the coupling efficiency of the laser beams B1 to B7 to the multimode optical fiber 30 is 0.9. Therefore, when each output of the GaN-based semiconductor lasers LD1 to LD7 is 100 mW, a combined laser beam B having an output of 630 mW (= 100 mW × 0.9 × 7) is obtained.
[0056]
Next, the fixing structure of the multimode optical fiber 30 will be described with reference to FIGS. The fiber block 43 is made of transparent glass, and is bonded and fixed to the base plate 42 with an ultraviolet curable adhesive. The fiber holder 46 is also made of transparent glass, and is bonded and fixed to the fiber block 43 with an ultraviolet curable adhesive. Further, the incident end portion of the multimode optical fiber 30 is also bonded and fixed to the upper surface of the fiber holder 46 with an ultraviolet curable adhesive. A fiber sealing portion 48 is formed on the lateral wall surface of the package 40, and the multimode optical fiber 30 having a metal tube (not shown) in the corresponding portion uses a brazing material for the fiber sealing portion 48. Is fixed.
[0057]
Here, the upper surface of the fiber holder 46 is processed with high flatness, whereby the multi-mode optical fiber 30 is fixed in a thin layer state having a thickness of 1 μm or less of an ultraviolet curable adhesive. If the upper surface of the fiber holder 46 has large irregularities, it is impossible to make the ultraviolet curable adhesive into such a thin layer state.
[0058]
Also, the fixing surface of the fiber block 43 to the base plate 42 and the fiber holder 46 and the fixing surface of the fiber holder 46 to the fiber block 43 are processed to have a high flatness, whereby the fiber block 43 is fixed to the base plate 42. The fiber block 43 and the fiber holder 46 are also fixed in a thin layer state of an ultraviolet curable adhesive having a thickness of 1 μm or less.
[0059]
As described above, when the base plate 42, the fiber block 43, the fiber holder 46, and the multimode optical fiber 30 are fixed in a thin layer state having a thickness of 1 μm or less of the ultraviolet curable adhesive, the ultraviolet curable adhesive is bonded. Expansion and contraction when a temperature change is applied to the agent can be suppressed, and sufficient fixing accuracy can be obtained. In the present embodiment, specifically, the coupling efficiency between the combined laser beam B and the multimode optical fiber 30 is 90% or more.
[0060]
In the present embodiment, since the fiber block 43 and the fiber holder 46 that are holding members are formed of transparent glass, the ultraviolet ray is absorbed by the fiber block 43 when the ultraviolet curable adhesive is cured by irradiating the ultraviolet ray. Further, it can be prevented from being blocked by the fiber holder 46. Therefore, it is possible to freely set the irradiation direction of the ultraviolet rays, thereby realizing good workability.
[0061]
Next, a fiber module according to a second embodiment of the present invention will be described with reference to FIGS. 8 and 9, the same elements as those in FIGS. 3 to 5 are denoted by the same reference numerals, and description thereof will be omitted unless particularly necessary.
[0062]
FIG. 8 shows a side shape of the fiber module according to the second embodiment, and FIG. 9 shows an enlarged side shape of the optical fiber fixing portion. As shown in the drawing, in this fiber module, the fiber block 43 and the fiber holder 46 used in the first embodiment are omitted, and the multimode optical fiber 30 is a fiber bracket 49 fixed on the inner side of the lateral wall surface of the package 40. It is fixed to the side.
[0063]
Also in this case, the fixing surface of the fiber bracket 49 to the package 40 and the side surface which is the fiber fixing surface are processed to have a high flatness, whereby the fiber bracket 49 is to the package 40 and the multimode optical fiber 30 is to the fiber bracket. 49, an ultraviolet curable adhesive is fixed in a thin layer state having a thickness of 1 μm or less.
[0064]
In FIG. 9, the bonding range of the fiber bracket 49 to the package 40 is indicated by a, and the bonding range of the multimode optical fiber 30 to the fiber bracket 49 is indicated by b. In addition, the multimode optical fiber 30 is fixed to the fiber sealing portion 48 using a brazing material within a range indicated by c.
[0065]
As described above, since the multimode optical fiber 30 is fixed to the fiber bracket 49 in a thin layer state having a thickness of 1 μm or less, the ultraviolet curable adhesive is also used in this embodiment. Expansion and contraction when the temperature change is applied to the agent can be suppressed, and sufficient fixing accuracy can be obtained.
[0066]
In this embodiment, the multimode optical fiber 30 can be fixed to the fiber bracket 49 fixed to the inner side of the lateral wall of the package 40, and the fiber block 43 and the fiber holder 46 can be omitted. Can be formed.
[0067]
Here, a detailed description will be given of a process of bonding glass members with an ultraviolet curable adhesive like the fiber block 43 and the fiber holder 46. The surface of one glass member is a mirror surface, and the surface of the other glass member is provided with irregularities of 0.15 μm or more with an abrasive, and the surfaces are faced to each other and a load of several tens of grams is applied. The thickness is about 0.3 μm. In that case, if the surface roughness of the surface with the irregularities is about 0.3 μm at the maximum height Rmax, the thickness of the adhesive can be made about 0.3 μm.
[0068]
Specifically, with respect to the fiber block 43 and the fiber holder 46, the surface of the fiber holder 46 is a ground glass surface, and a gap due to irregularities is provided between them. Further, regarding the base plate 42 made of the fiber block 43 and the steel plate, a machining mark is provided on the base plate 42. The surface of the fiber bracket 49 is a ground glass surface.
[0069]
In addition, it is preferable to apply what does not generate | occur | produce outgas as an ultraviolet curable adhesive. By doing so, it is possible to prevent the optical element disposed in the package 40 from being deteriorated by the outgas, and to achieve a long life of the fiber module.
[0070]
As described above, the embodiment of the present invention that constitutes the combined laser light source has been described. However, the present invention is not limited thereto, and is generally applicable to a fiber module configured to collect light and enter the optical fiber, and The effect mentioned above is produced.
[Brief description of the drawings]
FIG. 1 is a plan view showing a part of a fiber module according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a portion of a semiconductor laser constituting the fiber module. FIG. 4 is a side view of the fiber module. FIG. 5 is a partial front view of the fiber module. FIG. 6 is a side view of the collimator lens used in the fiber module. )
FIG. 7 is a side view (1) and a front view (2) of a condenser lens used in the fiber module.
8 is a side view showing a fiber module according to a second embodiment of the present invention. FIG. 9 is an enlarged side view showing a part of the fiber module of FIG.
DESCRIPTION OF SYMBOLS 10 Heat block 11-17 Collimator lens 20 Condensing lens 30 Multimode optical fiber 30a Core of multimode optical fiber 40 Package 41 Package lid 42 Base plate 43 Fiber block 46 Fiber holder 48 Fiber sealing part 49 Fiber bracket LD1-7 GaN system Semiconductor laser B1-7 Laser beam B Combined laser beam

Claims (3)

With optical fiber,
A holding member for holding one end of the optical fiber;
A light source;
In a fiber module comprising an optical system that makes light emitted from this light source incident on the optical fiber from one end face thereof,
A fiber module, wherein the optical fiber is bonded and fixed to the holding member with a thinned ultraviolet curable adhesive. The fiber module according to claim 1, wherein the holding member is made of a transparent member. A multimode optical fiber as the optical fiber;
A plurality of semiconductor lasers as the light source;
The fiber module according to claim 1, further comprising a condensing optical system as the optical system that condenses laser beams respectively emitted from these semiconductor lasers and makes the laser beams enter the optical fiber.

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