Semiconductor laser device

Abstract

The invention comprises: a semiconductor laser light source (3), wherein the center of the light beam (Cb) is set at an inclination (α) so as to have a component facing the mounting surface (2ft) of the tube seat (2); a reflecting surface (4fm) for reflecting the laser light from the semiconductor laser light source (3) toward the lens (6); and a second reflecting surface (5fm) connected to the end of the reflecting surface (4fm) close to the semiconductor laser light source (3) and for reflecting the laser light toward the lens (6), wherein one of the reflecting surface (4fm) and the second reflecting surface (5fm) is composed of a dielectric multilayer film formed on a PD chip (41) for measuring the light amount of the laser light, and the inclination (β) of the reflecting surface (4fm) is set to a value obtained by subtracting a value smaller than the inclination (α) from 45°, and the inclination (γ) of the second reflecting surface (5fm) is set to a value obtained by subtracting a value larger than the inclination (α) from 45°.

Description

Technical Field

[0001] The present application relates to a semiconductor laser device. Background Art

[0002] In a semiconductor laser device for communication, if a photodiode chip (PD chip) for monitoring the output from a semiconductor laser chip (LD chip) is arranged on the rear end side of the LD chip, the ratio of the front light output to the rear light output becomes unstable, making it difficult to perform high-precision control. For this reason, a semiconductor laser device has been proposed in which the photodiode chip (PD chip) for monitoring the front light output is tilted 45° relative to the upper surface of the stem, so that the front light emitted from the LD chip is bent in a vertical direction (for example, see Patent Documents 1 and 2).

[0003] In addition, a structure is disclosed in which a laser beam is bent using a curved or non-planar optical reflector to converge onto an optical fiber in order to reduce optical coupling loss (for example, refer to Patent Document 3).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 8-116127 (Paragraphs 0022 to 0027, Figures 1 to Figure 4 )

[0005] Patent Document 2: Japanese Patent Application Laid-Open No. 2005-260223 (Paragraphs 0016 to 0030, Figs. 1 to Figure 2 )

[0006] Patent Document 3: Japanese Patent Publication No. 2008-535259 (Paragraphs 0019 to 0021, Figure 4 )

[0007] Here, since the laser emitted from the LD chip is diffused, the incident angle of the laser at the reflection surface changes according to the angle from the optical axis, thereby causing the reflectivity to be distributed. However, in the technologies disclosed in the above-mentioned documents, no consideration is given to the distribution of the reflectivity, and as a result, the intensity distribution of the laser is dispersed, and the communication quality may be degraded. Summary of the invention

[0008] The present application discloses a technology for solving the above-mentioned problems, and an object of the present application is to realize a semiconductor laser device capable of suppressing degradation of communication quality and reduction of optical output.

[0009] The semiconductor laser device disclosed in the present application comprises: a stem having a mounting surface disposed at a distance from and opposite to an emission port; a semiconductor laser light source arranged so that a beam center has a component facing the mounting surface; a reflecting surface reflecting laser light incident from the semiconductor laser light source toward the emission port; and a second reflecting surface connected to an end of the reflecting surface close to the semiconductor laser light source and reflecting laser light incident from the semiconductor laser light source toward the emission port, wherein one of the reflecting surface and the second reflecting surface is composed of a dielectric multilayer film formed on a photodiode for measuring the light quantity of the laser light, and when an inclination of the beam center relative to the mounting surface in a plane perpendicular to the mounting surface and including the beam center is set to α, an inclination β of the reflecting surface is set to a value obtained by subtracting a value smaller than α from 45°, and an inclination γ of the second reflecting surface is set to a value obtained by subtracting a value larger than α from 45°.

[0010] According to the semiconductor laser device disclosed in the present application, since the distribution of the incident angle is reduced by using two-stage reflection surfaces having different inclinations, it is possible to obtain a semiconductor laser device capable of suppressing the degradation of communication quality and the reduction of optical output. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1A and Figure 1B They are respectively a top view and a cross-sectional view of the semiconductor laser device according to the first embodiment.

[0012] Figure 2 This is a graph showing the incident angle dependency of the reflectivity of laser light on the surface of the PD chip.

[0013] Figure 3 This is a diagram showing the angular relationship between laser light and a reflecting surface in the semiconductor laser device according to the first embodiment.

[0014] Figure 4 This is a cross-sectional view of a semiconductor laser device according to the second embodiment.

[0015] Figure 5 This is a cross-sectional view of a semiconductor laser device according to a third embodiment.

[0016] Fig. 6A and Figure 6B They are respectively a top view and a cross-sectional view of the semiconductor laser device according to the third embodiment. DETAILED DESCRIPTION

[0017] Implementation Method 1

[0018] Figure 1A to Figure 3 is a diagram for explaining the structure and operation of the semiconductor laser device according to the first embodiment. Figure 1A , Figure 1B This is a top view of the semiconductor device as viewed from the perspective mirror side. Figure 1A ), and by Figure 1A A cross-sectional view of a surface perpendicular to the upper surface (mounting surface) of the semiconductor laser device stem cut along the line A-A and including the center of the laser beam ( Figure 1B ).in addition, Figure 2 is a graph showing the incident angle dependence of the reflectivity of the laser light at the surface of the PD chip. Figure 3 It means that Figure 1B A diagram showing the angular relationship between the laser and the reflective surface under corresponding positional relationships.

[0019] like Figure 1A , Figure 1B As shown, the semiconductor laser device 1 involved in each embodiment of the present application includes: an LD chip 31 for oscillating laser light; and a PD chip 41 for monitoring the intensity of the forward light emitted from the LD chip 31 and reflecting the forward light toward a lens 6. The lens 6, which is an emission port of the semiconductor laser device 1, is spaced apart from the mounting surface 2ft of the stem 2 on which the LD chip 31 and the PD chip 41 are mounted so that the optical axis X6 is perpendicularly arranged.

[0020] Furthermore, a second reflecting portion 5 is disposed between the PD chip 41 and the LD chip 31 in the stem 2. The second reflecting portion 5 has a second reflecting surface 5fm connected to the LD chip 31 side relative to the reflecting surface 4fm of the PD chip 41. The LD chip 31 is directed toward the center of the light beam Cb ( Figure 3 ) is configured to emit laser light toward the mounting surface 2ft in an inclined manner relative to the mounting surface 2ft, and is constructed so that the laser light emitted from the front end surface 3fe is reflected upward toward the lens 6 through the second reflecting surface 5fm and the reflecting surface 4fm.

[0021] For this purpose, the tilting platform 2ma for arranging the LD chip 31, the tilting platform 2mb for arranging the PD chip 41, and the tilting platform 2mc for arranging the second reflecting portion 5 of the stem 2 are provided with inclinations having the relationship described below. The LD chip 31 is mounted on the tilting platform 2ma via the LD submount 32, and the PD chip 41 is mounted on the tilting platform 2mb via the PD submount 42. Furthermore, the second reflecting surface 5fm is formed by mounting the PD chip 51 on the tilting platform 2mc via the PD submount 52.

[0022] In addition, the LD chip 31 and the LD submount 32 are collectively referred to as a semiconductor laser light source 3, and the PD chip 41 and the PD submount 42 are collectively referred to as a reflecting portion 4. Similarly, the PD chip 51 and the PD submount 52 are collectively referred to as a second reflecting portion 5. In addition, the semiconductor laser device 1 may include other components other than those shown in the figure, such as circuit components, but in this application, only optical elements are extracted for description.

[0023] The PD chip 41 functions as a monitor for measuring the intensity of the laser emitted from the LD chip 31, and forms a reflection surface 4fm that reflects the laser through a dielectric multilayer film. The dielectric multilayer film is a structure formed by stacking materials with different refractive indices into a layered structure. For example, by stacking Si and SiO2 into a film of a multilayer structure, the laser can be efficiently reflected. In addition, since the dielectric multilayer film can change the reflectivity of light by controlling the number of layers, a part of the required laser can be introduced into the PD chip 41 to measure the intensity. In addition, the PD chip 51 as the second reflection part 5, like the PD chip 41, forms a second reflection surface 5fm that reflects the laser through a dielectric multilayer film. In addition, it is not limited to the dielectric multilayer film, as long as it can be formed in a way that a part of the light is transmitted, it can also be configured to reflect the laser with a metal reflection film or the like.

[0024] Furthermore, the semiconductor laser device 1 involved in each embodiment of the present application is characterized in that the inclination α of the semiconductor laser light source 3, the inclination β of the reflection surface 4fm, and the inclination γ of the second reflection surface 5fm relative to the mounting surface 2ft are set according to the diffusion (diffusion angle θ) of the laser. Before describing the details, the reflection in the general laser semiconductor device disclosed in Patent Documents 1 and 2 is described.

[0025] For example, when the diffusion angle θ from the center of the light beam Cb is 0°, that is, in the case of parallel light, even if the LD chip is arranged parallel to the upper surface of the stem and only the reflection surface inclined at 45° is used to reflect upward toward the lens, the incident angle is all 45°. That is, when only parallel light is processed, it is sufficient to reflect with a reflection surface having an inclination of 45° to the upper surface of the stem, that is, 135° (180°-45°) to the laser beam, as described in Patent Documents 1 and 2.

[0026] However, in reality, the laser light from the LD chip is emitted in a manner that has a diffusion of ±θ from the beam center Cb. At this time, for example, the incident angle of the light that diffuses toward the lens side from the beam center Cb is greater than that of the light from the beam center Cb, and the incident angle of the light that diffuses toward the stem side from the beam center Cb is smaller than that of the light from the beam center Cb. That is, the incident angle of the light at the end portion that diffuses toward the stem side relative to the beam center Cb becomes the minimum value (45-θ), and the incident angle of the light at the end portion that diffuses toward the lens side relative to the beam center Cb becomes the maximum value (45+θ).

[0027] Here, for example, when an LD chip with a diffusion angle θ=40° is used, the incident angle is 5 to 85°, resulting in a difference of 80° (=2θ), as shown in FIG. Figure 2As shown, the distribution of reflectivity spreads from less than 70% to nearly 95%, the intensity distribution of the laser collapses, and the communication quality may deteriorate. In view of this, for example, the LD chip is tilted downward by 20° (α=20), and in order to compensate for the change in the direction of the reflected light toward the lens 6 caused by the tilt, the tilt β of the PD chip is reduced from 45° to half of α (=10°) (β=45-α / 2).

[0028] Then, the inclination of the PD chip relative to the beam center Cb becomes 10° less than 135° (=α-β). Therefore, the maximum geometric incident angle is 75° (=45+θ-α+β), and the minimum is -5° (=45-θ-α+β). Considering that the minimum value of the reflectivity distribution is 0°, the difference is narrowed to 75° (=75-0). However, the part with an incident angle below 0° moves downward compared to the original LD ​​chip, which means it is not toward the lens side, so the utilization rate of the laser is reduced.

[0029] In contrast, in the semiconductor laser device 1 of the present application, in addition to the LD chip 31 and the reflection surface 4fm in the above-mentioned inclined relationship, a second reflection surface 5fm is provided which is continuous with the reflection surface 4fm and has a smaller inclination than the reflection surface 4fm. Figure 3 As shown, the inclination β of the reflection surface 4fm of the PD chip 41 relative to the direction D2 parallel to the mounting surface 2ft of the stem 2 is set to the above-mentioned 45-α / 2, the inclination γ of the second reflection surface 5fm is set to be smaller than the inclination β, and the angle formed with the beam center Cb is set to be greater than 135°. That is, the angle of the reflection surface 4fm relative to the beam center Cb is set to be less than 135°, and the angle of the second reflection surface 5fm relative to the beam center Cb is set to be greater than 135°.

[0030] More specifically, by setting the inclination γ to 45-(α+θ) / 2, as described later, the ratio of the beam can be made Figure 3 The entire range of the light beam center Cb upward and the light beam in the range of θ / 2 downward from the light beam center Cb are irradiated to the reflecting surface 4fm. In addition, when it is defined as γ=45-(α+θ) / 2, the condition for making the angle of the second reflecting surface 5fm relative to the light beam center Cb greater than 135° is α<θ.

[0031] For example, if α is set to 20° as described above with respect to θ=40°, β=35°, γ=15°, the angle of the reflecting surface 4fm relative to the beam center Cb is 125°, and the angle of the second reflecting surface 5fm relative to the beam center Cb is 145°. That is, the angle of the reflecting surface 4fm relative to the beam center Cb is 10° less than 135°, and the angle of the second reflecting surface 5fm relative to the beam center Cb is 10° greater than 135°.

[0032] If the amount of decrease (difference) in the angle of the reflecting surface 4fm relative to the beam center Cb from 135° is set to Δ4, the maximum value of the incident angle at the reflecting surface 4fm becomes 75° (=45+θ-Δ4), which is smaller than the above-mentioned case of simply tilting 45° (85°). On the other hand, if the increment (difference) in the angle of the second reflecting surface 5fm relative to the beam center Cb from 135° is set to Δ5, the minimum value of the incident angle at the second reflecting surface 5fm becomes 15° (=45-θ-Δ5), and the difference is narrowed to 70°. At this time, the incident angle with respect to the reflecting surface 4fm becomes 15°, which is the same as the minimum value, at the portion tilted 20° (=θ / 2) downward from the beam center Cb.

[0033] To this end, by setting the portion tilted 20° downward from the center of the light beam Cb as the boundary angle Ab and setting it as the boundary connected to the second reflection surface 5fm, the minimum value of the incident angle can be maintained at more than 15°. The incident angle to the second reflection surface 5fm at the boundary angle Ab is 35° (=45-Ab+Δ5), and the incident angle at the reflection surface 4fm changes from 75° to 15° from the end of the side close to the lens 6 to the boundary portion between the second reflection surface 5fm. Similarly, the incident angle at the second reflection surface 5fm changes from 35° to 15° from the boundary portion between the reflection surface 4fm and the end of the side close to the LD chip 31. That is, by narrowing the difference in the incident angle to 60°, the distribution of the reflectivity can be suppressed, the intensity distribution of the laser can be aligned, and high communication quality can be maintained.

[0034] In addition, according to the relationship of β=45-1 / 2α, Δ4=α / 2, and the maximum value of the incident angle at the reflection surface 4fm is 45+θ-α / 2. In addition, since Δ5=45-α-γ, the minimum value of the incident angle at the second reflection surface 5fm is 90-θ-α-γ. Therefore, the boundary angle Ab becomes θ+γ+α / 2-45, and the incident angle at the second reflection surface 5fm at the boundary angle Ab becomes 135-θ-2γ-3 / 2α.

[0035] At this time, in the reflection surface 4fm, the laser light is reflected only on the side closer to the lens 6 than the foot fp4 of the perpendicular line drawn from the light-emitting point 3s. Similarly, in the second reflection surface 5fm, the laser light is reflected only on the side closer to the lens 6 than the foot fp5 of the perpendicular line drawn from the light-emitting point 3s, so that the component not directed toward the lens 6 side is suppressed, and the utilization rate of the laser light can also be ensured. These are established in any combination of α and θ that satisfies α<θ by setting the boundary between the reflection surface 4fm and the second reflection surface 5fm at an appropriate position.

[0036] In addition, the above-mentioned boundary angle Ab is a boundary for keeping the minimum value of the incident angle at the reflection surface 4fm above the minimum value of the incident angle at the second reflection surface 5fm. If the boundary is set to an angle smaller than the boundary angle Ab, the minimum value of the incident angle at the reflection surface 4fm increases. However, in this case, the amount of light that can be monitored by the PD chip 41 is reduced, so the boundary can be appropriately set according to the importance.

[0037] On the other hand, since the minimum value increases in angle by the same amount as the increment Δ5 of the angle between the beam center Cb and the second reflecting surface 5fm from 135°, the increment Δ5 from 135° can also be set to a value greater than 0, without being restricted to the above definition (γ=45-(α+θ) / 2). However, in this case, for the position of the boundary angle Ab incident on the reflecting surface 4fm, if α increases by 1°, it decreases by 0.5° from θ, and if Δ5 increases by 1°, it decreases by 1° in the same manner, and approaches the incident position of the beam center Cb. That is, it becomes Ab=θ-Δ5-α / 2.

[0038] As described above, since the second reflecting portion 5 is formed by using the PD submount 52 and the PD chip 51 which are cheaper than the optical reflecting mirror, the semiconductor laser device 1 can be manufactured at low cost. Furthermore, if the second reflecting portion 5 is also used as a light monitor from the LD chip 31, the monitor current for detecting the light output that can be obtained is large.

[0039] Implementation Method 2

[0040] In the first embodiment, an example in which the second reflection portion is formed using a PD chip is described, but the present invention is not limited thereto. In the second embodiment, an example in which the second reflection portion is formed using a reflection member utilizing a difference in refractive index is described. Figure 4 FIG. 2 is a diagram for explaining the structure of a semiconductor laser device according to Embodiment 2, and is similar to the diagram used in the description of Embodiment 1. Figure 1B In the semiconductor laser device according to the second embodiment and the later described third embodiment, the structure other than the second reflection portion is the same as that described in the first embodiment, and the structure used in the first embodiment is used. Figure 2 and Figure 3 , and descriptions of the same parts are omitted.

[0041] like Figure 4As shown, in the semiconductor laser device 1 involved in the second embodiment, instead of the PD chip 51 and the PD sub-mount 52 described in the first embodiment, a reflecting component 53 utilizing the difference in refractive index is installed on the tilting stage 2mc, thereby forming the second reflecting portion 5. In this case, a part of the required laser light can also be introduced into the PD chip 41. In addition, the reflecting component 53 can be a prism reflecting mirror as long as it can reflect the laser light. On the other hand, in the case of a so-called reflecting mirror component having a high reflection film formed on the surface, as in the later-described third embodiment, the angle setting can be performed without considering the minimum value of the incident angle at the second reflecting surface 5fm.

[0042] In addition, in the semiconductor laser device 1 according to the second embodiment, since the second reflecting portion 5 has no function of measuring light intensity, it is important to set the ratio of the laser light incident on the reflecting surface 4fm, i.e., the boundary. For this purpose, by defining γ=45-(α+θ) / 2, for example, the boundary angle Ab is fixed at the position of θ / 2 from the beam center Cb toward the stem 2 side, the monitorable emission range is determined, and stable monitoring, i.e., control of the light intensity can be performed.

[0043] Furthermore, although the reflective member 53 may be disposed on the tilt stage 2mb and the PD chip 41 may be disposed on the tilt stage 2mc side, in this case, it is also preferable to appropriately determine the boundary angle Ab and set the monitorable emission range.

[0044] In the semiconductor laser device 1 according to the second embodiment, similarly to the first embodiment, by narrowing the difference in the incident angle, it is possible to suppress the distribution of reflectance, align the intensity distribution of laser light, and maintain high communication quality.

[0045] Implementation 3

[0046] In the first or second embodiment, the second reflecting portion is formed by mounting a PD chip or a reflecting member on a tilting stage, but the present invention is not limited thereto. In the third embodiment, the second reflecting portion is formed by mirror-finishing the tilting stage itself. Figure 5 This is a diagram for explaining the structure of the semiconductor laser device according to the third embodiment, and is similar to the diagram used in the description of the first embodiment. Figure 1B The corresponding cross-sectional view.

[0047] like Figure 5As shown, in the semiconductor laser device 1 involved in the third embodiment, the surface of the tilting stage 2mc is mirrored instead of the PD chip 51 and the PD submount 52 described in the first embodiment to form the second reflecting portion 5. In this case, a part of the required laser light can also be introduced into the PD chip 41. In addition, the tilting stage 2mc is connected to the reflecting surface 4fm in such a manner that the protrusion amount from the mounting surface 2ft is increased compared with the first or second embodiment, so that it protrudes more than the tilting stage 2mb.

[0048] The mirror finish can also be formed by applying pressure gold plating to the surface of the stem 2, or by forming other metal reflective films. Figure 2 As shown in the figure, the reflectivity at the surface of the stem 2 can be 70% or more, while the reflectivity at the surface of the stem 2 can be 100%. In addition, this structure does not need to use the PD chip 51 and the PD sub-mount 52 or the reflective component 53 as the second reflector 5 as in the first and second embodiments, so that low cost can be achieved. In addition, the PD sub-mount 42 and the PD chip 41 forming the reflective surface 4fm can be positioned by contacting with the wall surface of the tilting table 2mc during the manufacturing process, so the positioning of the PD sub-mount 42 and the PD chip 41 becomes easy, and productivity is improved.

[0049] In the third embodiment, similarly to the second embodiment, the second reflecting portion 5 does not have a function of measuring light intensity, so the ratio of the laser light incident on the reflecting surface 4fm, i.e., the setting of the boundary angle Ab, becomes important. Therefore, by defining, for example, γ=45-(α+θ) / 2, the boundary angle Ab is fixed at the position of θ / 2 from the beam center Cb toward the stem 2 side, and the monitorable emission range is determined, so that stable monitoring, i.e., control of light intensity can be performed.

[0050] On the other hand, as described above, since the reflectivity at the second reflective surface 5fm that has been mirrored can achieve 100%, there is no need to reduce the maximum value of the incident angle at the reflective surface 4fm, and only the improvement of the minimum value and the range of the incident light beam need to be focused on. Furthermore, in the second reflective surface 5fm, there is no need to consider the distribution of the incident angle, and only the condition that the end of the angle θ from the center Cb of the laser beam to the bottom is located above the foot fp5 of the perpendicular line from the light-emitting point 3s can be used.

[0051] In the semiconductor laser device 1 according to the third embodiment, similarly to the first and second embodiments, by narrowing the difference in the incident angle, it is possible to suppress the distribution of reflectance, align the intensity distribution of laser light, and maintain high communication quality.

[0052] Implementation 4

[0053] In the above-mentioned first to third embodiments, an example of arrangement of the reflection surface on the plane perpendicular to the mounting surface and including the center of the light beam is described. However, in the present fourth embodiment, an example of arrangement of the reflection surface on the mounting surface is described. Fig. 6A , Figure 6B 4 is a diagram for explaining the structure of the semiconductor laser device according to the fourth embodiment, and is a plan view of the semiconductor laser device as viewed from the lens side ( Fig. 6A ), and by Fig. 6A A cross-sectional view perpendicular to the mounting surface of the semiconductor laser device taken along the BB line ( Figure 6B ). In addition, the configuration of the reflecting surface in the plane perpendicular to the mounting surface and including the center of the light beam is described based on the example of Embodiment 1, and the configuration of the reflecting surface in Embodiment 1 is described based on the example of Embodiment 1. Figure 2 and Figure 3 , and descriptions of the same parts are omitted.

[0054] like Fig. 6A , Figure 6B As shown, the semiconductor laser device 1 according to the fourth embodiment has a reflector 4 and a second reflector 5 arranged on a surface parallel to the mounting surface 2ft of the stem 2 so as to sandwich the beam center Cb. －R , and left reflection part 4 －L And, relative to the right reflection surface 4fm －R and right second reflective surface 5fm －R , left reflective surface 4fm －L and the left second reflective surface 5fm －L The beams are symmetrically arranged with a plane perpendicular to the mounting surface 2ft and including the beam center Cb as a symmetry plane, and are inclined upward as they are farther away from the symmetry plane.

[0055] That is, in addition to the inclination α and the inclination β in the plane perpendicular to the mounting surface 2ft and including the beam center Cb described in the first to third embodiments, the reflecting surface 4fm and the second reflecting surface 5fm are also inclined in a manner that the farther away from the beam center, the more upward. As a result, when viewed from the side opposite to the front end surface 3fe of the LD chip 31, as shown in FIG. Figure 6B As shown, the reflecting surface 4fm is V-shaped like the second reflecting surface 5fm (not shown).

[0056] Thus, by forming the reflection surface 4fm and the second reflection surface 5fm into a V-shape, it is possible to suppress the incident light from the semiconductor laser light source 3 on the surface parallel to the mounting surface 2ft. Fig. 6A As a result, more laser light enters the lens 6, and a decrease in light output can be suppressed.

[0057] In addition, Fig. 6A , Figure 6B In order to simplify the description, the reflection member 53 described in the second embodiment is depicted, but the present invention is not limited thereto, and the second reflection portion 5 may be in the form described in the first embodiment or the third embodiment.

[0058] In addition, although the present application records various illustrative embodiments and examples, the various features, forms and functions recorded in one or more embodiments are not limited to the application of specific embodiments, and can also be applied to the embodiments alone or in various combinations. Therefore, countless unillustrated variations can be imagined within the technical scope disclosed in the present specification. For example, it includes the case where at least one constituent element is deformed, added or omitted, and also includes the case where at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0059] For example, although the example of providing the lens 6 as the emission port has been described, the present invention is not limited to this, and the reflected light may be directly irradiated to the end face of the optical fiber as long as it is emitted toward the emission port facing the mounting surface 2ft of the stem 2. In addition, although the example of providing the semiconductor laser light source 3, the reflecting portion 4, and the second reflecting portion 5 on the tilting stages 2ma to 2mc of the stem 2 has been shown, the present invention is not limited to this. As long as the geometrical relationship between the beam center Cb and the reflecting surface 4fm and the second reflecting surface 5fm relative to the mounting surface 2ft is established, it may be installed on another component.

[0060] As described above, the semiconductor laser device 1 involved in each embodiment includes: a tube seat 2, which is spaced apart from and relatively arranged with a mounting surface 2ft relative to an emission port (for example, a lens 6); a semiconductor laser light source 3, which is arranged so that the beam center Cb has a component toward the mounting surface 2ft; a reflection surface 4fm, which reflects the laser light incident from the semiconductor laser light source 3 toward the emission port (lens 6); and a second reflection surface 5fm, which is connected to the end of the reflection surface 4fm on the side close to the semiconductor laser light source 3 and reflects the laser light incident from the semiconductor laser light source 3 toward the emission port (lens 6); The light is reflected from the emission port (lens 6), and one of the reflection surface 4fm and the second reflection surface 5fm is formed of a dielectric multilayer film formed on a photodiode (PD chip 41) for measuring the light amount of the laser. If the inclination of the beam center Cb relative to the mounting surface 2ft (direction D2) in a plane perpendicular to the mounting surface 2ft and including the beam center Cb is set to α, the inclination β of the reflection surface 4fm is set to a value obtained by subtracting a value smaller than α from 45°, and the inclination γ of the second reflection surface 5fm is set to a value obtained by subtracting a value larger than α from 45°. Therefore, the maximum value of the incident angle becomes smaller, and the minimum value of the incident angle also becomes larger, so that the distribution of the reflectivity becomes smaller, thereby obtaining a semiconductor laser device 1 that can suppress the degradation of communication quality and the reduction of light output.

[0061] In particular, the boundary (boundary angle Ab) between the reflecting surface 4fm and the second reflecting surface 5fm is set on a side farther away from the semiconductor laser light source 3 than the foot of a perpendicular line drawn from the light-emitting point 3s of the semiconductor laser light source 3 to the reflecting surface 4fm, so that the laser light incident on the reflecting surface 4fm can be reliably reflected toward the lens 6.

[0062] If the inclination β is set to 45-α / 2 and the diffusion angle of the laser from the beam center Cb is set to θ, the boundary between the reflecting surface 4fm and the second reflecting surface 5fm is set at a position where the light beam is incident with an inclination (boundary angle Ab) toward the mounting surface 2ft relative to the beam center Cb becoming θ+γ+α / 2-45. Therefore, the minimum value of the incident angle to the reflecting surface 4fm and the minimum value of the incident angle to the second reflecting surface 5fm can be aligned, and the difference in the incident angles can be reliably reduced, thereby further suppressing the distribution of reflectivity and reliably preventing the degradation of communication quality.

[0063] At this time, if the inclination γ is set to 45-(α+θ) / 2, the light beam toward the lens 6 side from the light beam center Cb and the light beam diffused from the light beam center Cb to θ / 2 can be incident on the reflecting surface 4fm, and the ratio of the light beam toward the PD chip 41 can be maintained, and the light beam quantity can be accurately monitored. In particular, if the reflecting surface 4fm is formed by the PD chip 41, the light in the 3 / 4 angle range in the diffusion of the light beam can be monitored by the PD chip 41.

[0064] At this time, when the other of the reflection surface 4fm and the second reflection surface 5fm is also composed of a dielectric multilayer film formed on the photodiode (PD chip 41, PD chip 51), the entire area of ​​the light beam diffusion can be monitored by the PD chip 41 and the PD chip 51.

[0065] When the other of the reflecting surface 4fm and the second reflecting surface 5fm (the second reflecting portion 5 ) is formed by the reflecting member 53 utilizing the difference in refractive index, it can be manufactured at low cost by the same process as the semiconductor manufacturing process.

[0066] Since a portion of the stem 2 (the inclined surface of the tilting stage 2mc) is mirror-finished to form the second reflecting surface 5fm, the cost can be reduced. In addition, only the minimum value of the incident angle of the reflecting surface 4fm needs to be taken into consideration, thereby increasing the degree of freedom in design.

[0067] Since the reflecting surface 4fm and the second reflecting surface 5fm (the right reflecting surface 4fm －R And the left reflective surface 4fm －L , and the right second reflective surface 5fm －R And the left second reflective surface 5fm －L ) are symmetrically arranged with the planes perpendicular to the mounting surface 2ft and containing the beam center Cb as symmetry planes, and are tilted so as to move away from the mounting surface 2ft as they move away from the symmetry planes, thereby suppressing the diffusion of laser light in the plane parallel to the mounting surface 2ft after being incident from the semiconductor laser light source 3. As a result, the proportion of laser light deviating from the lens 6 can be suppressed, and the reduction of light output can be suppressed.

[0068] Description of Reference Numerals

[0069] 1...semiconductor laser device; 2...tube holder; 2ft...mounting surface; 3...semiconductor laser light source; 3fe...front end surface; 3s...light emitting point; 4...reflecting part; 41...PD chip; 4fm...reflecting surface; 5...second reflecting part; 51...PD chip; 53...reflecting component; 5fm...second reflecting surface; 6...lens; Ab...boundary angle; Cb...beam center; α...inclination; β...inclination; γ...inclination; θ...diffusion angle.

Claims

1. A semiconductor laser device, characterized in that: The semiconductor laser device comprises: A tube seat having a mounting surface spaced apart from and opposite to the ejection port; A semiconductor laser light source, arranged so that the center of the light beam has a component toward the mounting surface; A reflecting surface, which reflects the laser light incident from the semiconductor laser light source toward the emission port; as well as The second reflecting surface is connected to the end of the reflecting surface close to the semiconductor laser light source, and reflects the laser light incident from the semiconductor laser light source toward the emission port. One of the reflection surface and the second reflection surface is formed of a dielectric multilayer film formed on a photodiode that measures the light amount of the laser beam, If the inclination of the center of the light beam relative to the mounting surface in a plane that is perpendicular to the mounting surface and contains the center of the light beam is set to α, then the inclination β of the reflecting surface relative to the mounting surface is set to a value obtained by subtracting a value smaller than α from 45°, and the inclination γ of the second reflecting surface relative to the mounting surface is set to a value obtained by subtracting a value larger than α from 45°.

2. The semiconductor laser device according to claim 1, wherein The boundary between the reflection surface and the second reflection surface is set on a side farther from the semiconductor laser light source than the foot of a perpendicular line drawn from the light-emitting point of the semiconductor laser light source to the reflection surface.

3. The semiconductor laser device according to claim 1 or 2, characterized in that: If the inclination β is set to 45 － α / 2, the diffusion angle of the laser from the center of the beam is set to θ, Then the boundary between the reflection surface and the second reflection surface is set at an inclination Ab relative to the center of the light beam toward the mounting surface to be θ+γ+α / 2 － The position where the 45° light beam is incident.

4. The semiconductor laser device according to claim 3, wherein: The inclination γ is set to 45 － (α+θ) / 2.

5. The semiconductor laser device according to any one of claims 1, 2 and 4, characterized in that: The other of the reflection surface and the second reflection surface is also formed of a dielectric multilayer film formed on the photodiode.

6. The semiconductor laser device according to any one of claims 1, 2 and 4, characterized in that: The other of the reflection surface and the second reflection surface is formed of a reflection member utilizing a difference in refractive index.

7. The semiconductor laser device according to any one of claims 1, 2 and 4, characterized in that: The second reflecting surface is formed by mirror-finishing a portion of the stem.

8. The semiconductor laser device according to any one of claims 1, 2 and 4, characterized in that: The reflection surface and the second reflection surface are respectively arranged to be symmetrical with respect to a plane perpendicular to the mounting surface and including the center of the light beam as a symmetry plane, and are inclined so as to be separated from the mounting surface as they are away from the symmetry plane.

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