JPH0583712U - Semiconductor laser module - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the tolerance of misalignment in the direction perpendicular to the optical axis of the optical fiber and facilitate the welding technique. [Structure] The structure of the present invention comprises a semiconductor laser 30 and a side wall 44b defining a passage of laser light, and this side wall has a supporting portion 28 serving as a passage of laser light.
Next, there is a coupling portion 50 having a flat abutting surface that abuts the side wall of the through hole for laser light and a concave curved surface provided on the side opposite to the abutting surface. Next, it holds a ferrule to which the optical fiber is fixed and a lens system for irradiating the optical fiber with laser light, and has a sleeve 56 whose tip portion has a convex curved surface that abuts against the concave curved surface of the coupling portion. . The concave curved surface and the convex curved surface of the coupling portion form part of a spherical surface having substantially the same radius of curvature. And the support part, the coupling part and the sleeve are
They are fixed to each other in this order. By doing so, it is possible to achieve the above-mentioned object and provide a semiconductor laser module with high productivity.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a structure in a semiconductor laser module.

[0002]

[Prior Art]

 For the structure of a conventional semiconductor laser module, see, for example, 1987 NEC Technical Report Vol. 40, No. 5 are disclosed. A semiconductor laser module of this conventional structure is shown in a sectional view in FIG. According to this structure, the LD chip-on-carrier is hybrid-mounted on the same base having the internal lens 12 together with the monitor PD and the chip thermistor. The light emitted from the LD chip 10 is converted into a gentle convergent beam by the inner lens 12, and is guided to the outside of the package via the hermetically sealed glass window 14 on the side wall of the package. In this state, the outer lens 16 is first fixed to the package side, and then the pigtail of the single mode fiber 22 is fixed via the slide ring 18. YAG welding is used for these fixing operations. Further, the two lenses, that is, the inner lens 12 and the outer lens 16 are both metallized on their side surfaces and then fixed by using a high melting point solder.

Further, when the position of the single mode fiber 22 is adjusted, the slide ring 18 is slid in the vertical direction to adjust the displacement in the direction perpendicular to the optical axis, and the position is adjusted in the optical axis direction. Has a structure in which an optical fiber is slid left and right in a slide ring for adjustment.

[0004]

[Problems to be solved by the device]

 However, the tolerance of positional deviation in the direction perpendicular to the optical axis of the optical fiber (tolerance) is as small as a few μm, so precise YAG welding technology processing was required when fixing the optical fiber to the required location. .. According to a report disclosed in Technical Report on Optical Quantum Electronics OQE86-38 of the Institute of Electronics and Communication Engineers of 1986, the tolerance of the positional deviation of the optical fiber in the vertical direction with respect to the first lens and the second lens, which are fixed in advance, is the coupling efficiency. It can be seen that the permissible deterioration amount is 0.5 dB, which is an extremely small value of ± 2.1 μm. Therefore, a high-precision welding technique is required when performing YAG welding after adjusting the optical fiber, and the yield also deteriorates.

An object of the present invention is to provide a semiconductor laser module having a structure that has a large tolerance of misalignment in the direction perpendicular to the optical axis of the optical fiber and does not require a highly accurate YAG welding technique. ..

[0006]

[Means for Solving the Problems]

 In order to achieve this purpose, the structure of the present invention has the following features.

A support portion for a semiconductor laser, which comprises a semiconductor laser and a side wall defining a passage of the laser light, and an outer surface of the side wall around the passage of the laser light is a flat surface. have.

Next, a through hole for laser light, a flat abutting surface that abuts the flat surface of the side wall around the through hole, and an abutting surface around the through hole. And a coupling portion having a concave curved surface provided on the opposite side.

Next, a sleeve having a ferrule to which the optical fiber is fixed and a lens system for irradiating the optical fiber with laser light, and having a convex curved surface whose tip end abuts against the concave curved surface of the coupling portion. The concave curved surface of the coupling portion and the convex curved surface of the sleeve respectively form part of a spherical surface having substantially the same radius of curvature.

The support portion, the coupling portion, and the sleeve described above are fixed to each other in this order, and the support portion and the sleeve are coupled via this coupling portion.

Further, in the semiconductor laser module, preferably, a reinforcing sleeve fixed so as to cover the above-mentioned coupling portion from the outside may be provided between the side wall of the support portion and the sleeve.

[0012]

[Action]

 According to the semiconductor laser module of the present invention, a part of the side wall surface of the support portion for the semiconductor laser on the side of the coupling portion has a flat surface which can be slid smoothly in abutment with the coupling portion. In addition, the joint portion has a flat abutting surface and a concave curved surface, and the flat abutting surface abuts the side wall surface of the support portion to thereby move in the X-axis direction and the Y-axis direction (see FIG. 2). Can be slipped on. Further, the tip of the sleeve is processed into a convex curved surface so as to abut against the concave curved surface of the connecting portion. Both curved surfaces form a part of a spherical surface having substantially the same radius of curvature. Therefore, the convex curved surface of the sleeve can smoothly rotate with respect to the concave curved surface of the coupling portion. Therefore, prior to fixing the support part, the coupling part, and the sleeve, the semiconductor laser adjusts the angular displacement by aligning the optical axis of the parallel beam in the vertical direction and rotating the coupling part and the sleeve. To do. The tolerance of the sleeve with respect to the X-axis direction and the Y-axis direction is as large as ten and several μm as shown in FIG. 4, and YAG welding after position adjustment is easy.

[0013]

【Example】

 The main configuration of the present invention will be described below with reference to the drawings. However, the drawings used in this description only schematically show the shapes, sizes, and arrangement relationships of the constituent components to the extent that these inventions can be understood.

The configuration of the semiconductor laser module according to the present invention can be roughly classified into the following three types. First, it has a supporting portion that supports the semiconductor laser and that has side walls that define the passage of the laser light. Second, it has a flat surface that can slide in the X-axis and Y-axis orthogonal to the optical axis. The sleeve is composed of a coupling part having a concave curved surface on the opposite side, and thirdly, a lens system for irradiating the optical fiber with laser light and a ferrule fixing the optical fiber. Hereinafter, the configuration of the present invention will be described in detail.

<First Embodiment> FIG. 1 is a plan view showing an essential part of a first embodiment used in a semiconductor laser module of the present invention. FIG. 2 is a sectional view taken along the line AA of FIG. The configuration of the present invention and the optical axis alignment of each device will be described below with reference to FIGS. 1 and 2. The supporting portion 28 for the semiconductor laser includes a semiconductor laser 30. The semiconductor laser 30 is fixed to the spacer 48 via the heat sink 32, the sub-carrier 34, etc., and the spacer 48 is fixed to the support 44, in this embodiment, the bottom 44a of the case. In this case, it is preferable to fix the sub carrier 34 and the base 36 with solder or the like. Further, a first lens 38 is provided as a lens system on the support portion 28. The first lens 38 is fixed to the lens holder 40 by soldering or press fitting, and the lens holder 40 is used to fix the semiconductor laser 30. The output light is aligned so that it becomes a parallel beam, and is fixed to the lens holder base 42. Further, the semiconductor laser 30 and the lens holder 40 are fixed to the base 36. As a fixing method at this time, soldering or YAG welding is used.

Next, as can be seen from FIG. 2, the support portion 28 includes a side wall 44b that defines a passage of laser light. In this embodiment, the side wall 44b constitutes a wall which is orthogonal to the base 44a of the case which is the support body 44, and has a cylindrical wall having an L-shaped cross section in a required peripheral region of the optical axis. A laser beam passage 45 is defined by being surrounded by. A window glass 46 is provided at the tip of the cylindrical inner protruding portion of the side wall 44b. Then, the lens holder 40, the holder base 42, the base 36, the spacer 48, etc. are aligned in a predetermined manner so that the laser beam from the semiconductor laser travels straight from the window glass 46 on the side surface of the case 44 in the optical fiber direction. The first lens 38 is fixed to the case 44. The outer surface of the side wall 44b of the case 44, that is, the surface that abuts the coupling portion 50 is flat, and the abutment of the coupling portion 50 causes the optical axis direction to be the Z axis as shown in FIG. If so, it can be slid in two directions orthogonal to the optical axis O, that is, the X-axis direction and the Y-axis direction. The coupling portion 50 includes a laser beam through hole 50a, and has a flat surface that abuts against the flat surface of the side wall 44b of the support portion 28 described above. In addition, the portion of the coupling portion 50 that abuts the sleeve 52 is a concave curved surface, and the abutting end surface of the sleeve 52 is a convex curved surface. Therefore, both should be abutted and coupled so that they can rotate smoothly. Is possible. Therefore, both curved surfaces are formed by a part of a spherical surface having substantially the same radius of curvature. Further, the sleeve 52 includes a second lens as a lens system for causing the parallel laser beam emitted from the support portion 28 to enter the optical fiber 58. In this embodiment, the second lens 54 is spherical. Further, the sleeve 52 has a built-in ferrule 56 to which an optical fiber 58 is fixed, and the angular misalignment is performed according to the central axis of the second lens 54.

In this embodiment described above, the coupling portion 50 is formed in a ring shape having a through hole 50a through which laser light passes in the central portion thereof, and defines the through hole 50a in the central portion. The supporting portion 28 side of the area is made to project into a cylindrical shape. The outer diameter of the protruding portion is formed smaller than the inner diameter of the laser light passage 45 of the support portion 28, and when the connecting portion 50 is slid in the X-axis and Y-axis directions described above, the connecting portion 50 has a smaller diameter. The through hole 50a is regulated so as not to come off from the laser beam passage 45. Of course, it is also possible to form the connecting portion 50 into a ring shape, and in that case as well, it is necessary to have an abutment surface as a flat surface that abuts against the flat surface of the support portion 28 and can slide. .. The sleeve 52 has a function of causing the laser beam from the first lens 38 to form a spot on the incident end face of the optical fiber 58 by the second lens 54 and causing the laser beam to enter the optical fiber 58.

Next, after fixing the sleeve 52 using a jig, the sleeve 52 is placed on a fine movement stage and a rotating stage to adjust the angle of the optical axis. At this time, the angle adjustment is performed such that the semiconductor laser 30 emits light and the optical output of the optical fiber 58 is measured using an optical power meter so that the optical output power becomes maximum. Next, YAG welding is performed to fix the joint portion 50 and the case 44. Although FIG. 2 shows only one YAG weld 60, in practice it is preferred to weld several perimeters. In addition, an adhesive or soldering may be used for this fixing. At this time, the position of the ring 50 is displaced due to YAG welding, and the sleeve 52 is displaced. However, in the parallel beam, since the allowable range due to the deviation of the X axis or the Y axis, which is the direction perpendicular to the optical axis O, is large, the positional deviation of the ring 50 is less affected.

FIG. 4 shows the relationship between the positional deviation of the sleeve 52 in the direction perpendicular to the optical axis O and the deterioration amount (dB) of the coupling efficiency. In the figure, the horizontal axis represents the amount of positional deviation, and the vertical axis represents the amount of deterioration in coupling efficiency. According to this, it can be seen that the tolerance is about ± 2.1 μm when the allowable deterioration amount of the coupling efficiency is 0.5 dB, but the range is expanded to ± 20 μm.

Next, after adjusting the angle of the sleeve 52, YAG welding is performed to fix the sleeve 52 and the joint portion 50. Although FIG. 1 shows the YAG welded portion 62 at one place, in practice it is preferable to weld at several places around this. In addition, an adhesive or soldering may be used for this fixing. Although spherical lenses are used for the first lens 38 and the second lens 54 in this invention, aspherical lenses or GRIN lenses may be used.

<Second Embodiment> FIG. 3 is a cross-sectional view of an essential part for explaining the structure of a second embodiment of the semiconductor laser module of the present invention. In particular, FIG. 3 shows a portion of the ring 50 and the sleeve 52 that form a coupling portion that is coupled to the case 44 that emits the semiconductor laser. As can be understood from FIG. 3, the output light of the optical laser is not subjected to the first embodiment until it is collected by the first lens 38 (not shown) and the second lens 54 to the optical fiber 58 fixed in the ferrule 56. Adjust the optical axis exactly as in the example. After that, a reinforcing sleeve 68 is provided between the side wall 44b of the support portion 28 and the sleeve 52 so as to cover the ring 50 as the connecting portion from the outside, and the reinforcing sleeve 68 and the side wall 44b of the case and the reinforcing sleeve 68 and the sleeve 52 are provided. 52 and YAG are welded and fixed. In FIG. 3, YAG welds 70 and 72 are shown. In practice, it is preferable that the number of YAG welding points is several. In addition, an adhesive or soldering may be used for this fixing.

[0022]

[Effect of the device]

 As is apparent from the above description, according to the configuration of the present invention, the surfaces where the side wall of the semiconductor laser support portion and the coupling portion abut each other are flat surfaces when the semiconductor laser module is assembled. Therefore, it is possible to adjust the axial misalignment in the vertical direction by sliding the coupling part with respect to the support part in the direction perpendicular to the optical axis of the laser beam. In addition, since the concave and convex curved surfaces of the joint and the sleeve are formed as part of spherical surfaces with the same radius of curvature, the curved surfaces are made to abut each other and mutually rotated to adjust the angular deviation. It can be carried out. The slave is provided with a ferrule with an optical fiber inserted and a lens system. Using these supports, joints and sleeves, optical axis alignment, vertical axis alignment and angle alignment are performed in a parallel beam, and then the supports, joints and sleeves are fixed in order. The tolerance of the vertical misalignment of the fiber in the vertical direction can be expanded to ± 20 μm, which is about 10 times the tolerance which was ± 2.1 μm when the allowable deterioration amount of the coupling efficiency was 0.5 dB. Therefore, a highly efficient semiconductor laser module can be easily obtained with a high yield when forming the semiconductor laser module, which leads to an improvement in productivity.

[Brief description of drawings]

FIG. 1 is a plan view for explaining a first embodiment of a semiconductor laser module of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view for explaining a second embodiment of the semiconductor laser module of the present invention.

FIG. 4 is a diagram showing a relationship between a vertical position shift amount and a coupling efficiency deterioration amount.

FIG. 5 is a diagram for explaining a conventional semiconductor laser module.

[Explanation of symbols]

 28: Support for semiconductor laser 30: Semiconductor laser 32: Heat sink 34: Sub carrier 36: Base 38: First lens 40: Lens holder 42: Lens holder stand 44: Case (support) 46: Window glass 48: Spacer 50 : Ring 52: Sleeve 54: Second lens 56: Ferrule 58: Optical fiber 60, 62, 70, 72: YAG welded portion 68: Reinforcing sleeve

Claims (2)

[Scope of utility model registration request] 1. A semiconductor laser for a semiconductor laser, comprising: (a) a semiconductor laser and a side wall defining a passage of laser light, the outer surface of the side wall around the passage being a flat surface. A supporting portion; (b) a through hole for the laser beam; a flat abutting surface that abuts the flat surface of the side wall around the through hole; A coupling part having a concave curved surface provided on the side opposite to the abutting surface, (c) a ferrule to which an optical fiber is fixed, and a lens system for irradiating the optical fiber with the laser light are held. And a sleeve having a convex curved surface that abuts the concave curved surface of the coupling portion, and (d) the concave curved surface and the convex curved surface each form a part of a spherical surface having substantially the same radius of curvature. (E) The support portion, the coupling portion, and the sleeve are fixed to each other in this order. The semiconductor laser module according to claim Rukoto. 2. The semiconductor laser module according to claim 1, further comprising: a reinforcing sleeve fixed between the side wall of the support portion and the sleeve so as to cover the coupling portion from the outside. Characteristic semiconductor laser module.