Optical member, semiconductor laser device having the same, and laser module

Abstract

To provide an optical member capable of being correctly installed to an optical shaft of a laser light, and securing an attachment strength to a support member.SOLUTION: A laser light shaping unit 70 comprises a FAC lens array 73, a beam twister array 74, and first and second holders 71 and 72. The FAC lens array 73 collimates an expansion of an incident laser light LBE in a first shaft direction. The beam twister array 74 rotates the collimated laser light LBE by a collimator leans 73a by 90°. The first and second holders 71 and 72 hold the FAC lens array 73 and the beam twister array 74 so as to nip them. A height H1 of the FAC lens array 73 is lower than a height H2 of the beam twister array 74 along the first shaft direction by using a first surface 72a of the second holder 72 as a reference.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an optical member, and a semiconductor laser device and a laser module including the optical member. [Background technology]

[0002] In recent years, laser processing technology has been widely used in metal processing and the like. In laser processing, the use of semiconductor laser elements (also called direct diode lasers (DDLs)) allows for the miniaturization and high efficiency of laser light sources. A widely used technology uses multiple laser diode bars, each of which has multiple emitters that emit laser light, as semiconductor laser elements, and combines the laser lights to increase the output of the laser light output from the laser light source.

[0003] In addition, when using a laser diode bar, it is necessary to combine the laser beams emitted from the multiple emitters into a single laser beam, and before such combining, the shape of each laser beam may need to be appropriately shaped.

[0004] In view of this, it has been proposed to provide an optical member near the laser light emission end face of the laser diode bar to shape the laser light.

[0005] For example, Patent Document 1 proposes a configuration in which an optical member is attached to a support member that supports a laser diode bar via an adhesive. This optical member is an FAC lens array in which a plurality of collimating lenses (hereinafter referred to as FAC lenses) that collimate the spread of laser light in the fast axis direction are provided along the emitter arrangement direction. The FAC lens array is held by two holding members, which hold the FAC lens array by sandwiching it in the fast axis direction of the laser light immediately after emission. In addition, the holding member located closer to the support member is attached to the support member via an adhesive. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2021-132151 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the conventional configuration disclosed in Patent Document 1, the FAC lens array is warped in a predetermined direction using two holding members, thereby suppressing the occurrence of propagation loss of laser light.

[0008] By the way, when combining multiple laser beams, it may be easier to combine the laser beams by changing the rotation direction of each laser beam by 90 degrees. In such a case, a beam twister array is provided after the FAC lens array, in which multiple beam twisters that rotate the laser beams by 90 degrees are provided along the emitter arrangement direction.

[0009] However, when two different optical members are sandwiched and fixed between two holding members, the optical axis of the laser light may be tilted from the initial position due to processing variations of each optical member, etc. Furthermore, when attempting to adhere the holding member and the support member to correct this tilt, the holding member may come off the support member depending on the conditions.

[0010] The present disclosure has been made in consideration of these points, and its purpose is to provide an optical component that can be installed correctly with respect to the optical axis of laser light and that can ensure the attachment strength to a support member, as well as a semiconductor laser device and a laser module that are equipped with the same. [Means for solving the problem]

[0011] In order to achieve the above object, an optical member according to the present disclosure is an optical member including a collimating lens array, a beam twister array, and a first holder and a second holder for holding the collimating lens array and the beam twister array, wherein when a direction perpendicular to each of a traveling direction of a laser beam incident on the optical member and a fast axis direction of the laser beam are defined as a slow axis direction, the collimating lens array is a member including a collimating lens that parallelizes the spread of the laser beam in the fast axis direction and has a longitudinal direction in the slow axis direction, and the beam twister array is spaced from the collimating lens array along the traveling direction of the laser beam. a plurality of beam twisters that rotate the laser light collimated by the collimating lens by 90 degrees are arranged along the slow axis direction and are integrated into a single member, the first holder and the second holder that are arranged at intervals along the fast axis direction hold the collimating lens array and the beam twister array so as to sandwich them, the collimating lens array and the beam twister array are installed on a first surface of the second holder, and the height of the collimating lens array in the fast axis direction is lower than the height of the beam twister array in the fast axis direction based on the first surface of the second holder.

[0012] The semiconductor laser device according to the present disclosure at least comprises the optical member, a laser diode bar having a plurality of emitters each emitting laser light, and a support member on which the laser diodes are mounted, and is characterized in that the second holder is adhered to a side of the support member via the adhesive, thereby attaching the optical member to the support member, and each of the laser lights emitted from the plurality of emitters passes through the collimator lens array and the beam twister array, thereby parallelizing the expansion in the fast axis direction and rotating 90 degrees immediately after being emitted from the plurality of emitters.

[0013] The laser module according to the present disclosure at least comprises the semiconductor laser device, an optical coupling element which combines the multiple laser beams emitted from the multiple emitters and transmitted through the optical component, an external resonator mirror which reflects the laser beam combined by the optical coupling element toward the optical coupling element, and a housing which accommodates one or more of the semiconductor laser devices, the optical coupling element, and the external resonator mirror, wherein the emitter is provided with a reflective layer having a predetermined reflectance on a surface opposite to an emission end surface of the laser beam, an external resonator is formed between the external resonator mirror and the reflective layer of the emitter from which the laser beam is emitted, and the combined laser beam combined by the optical coupling element is emitted to the outside of the housing. Effect of the Invention

[0014] According to the present disclosure, the optical member can be correctly installed with respect to the optical axis of the laser light, and the attachment strength to the support member that supports the optical member can be ensured. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic configuration diagram of a semiconductor laser device according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a perspective view of a laser diode bar. [Figure 4] FIG. 2 is a perspective view of an FAC lens array. [Diagram 5] FIG. 2 is a perspective view of a beam twister array. [Figure 6] FIG. 1 is a schematic diagram of a laser light shaping unit for explaining a first technical problem that occurs in assembling the laser light shaping unit. [Figure 7] FIG. 13 is a schematic diagram of a laser light shaping unit for explaining a second technical problem that occurs in assembling the laser light shaping unit. [Figure 8] FIG. 3 is a diagram corresponding to FIG. 2 for explaining a technical problem that occurs in assembling a semiconductor laser device. [Figure 9]13 is a diagram showing a laser light shaping unit according to a modified example, viewed along the traveling direction of the laser light. FIG. [Figure 10] FIG. 11 is a schematic diagram illustrating the internal configuration of a laser module according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its application, or its uses.

[0017] (Embodiment 1) Fig. 1 is a schematic diagram of a semiconductor laser device according to embodiment 1. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a perspective view of a laser diode bar. Fig. 4 is a perspective view of an FAC lens array. Fig. 5 is a perspective view of a beam twister array.

[0018] In the following description, the laser light LB emitted from each of the multiple emitters 11 provided on the laser diode bar 10 is E The direction in which the laser beam LB travels is sometimes called the Z direction, and the direction in which the emitters 11 are arranged is sometimes called the X direction. The direction perpendicular to the Z direction and the X direction is sometimes called the Y direction. E The X direction corresponds to the fast axis direction, and the X direction corresponds to the slow axis direction. The fast axis and the slow axis will be explained later.

[0019] The Y direction is also the stacking direction of the laser diode bar 10 and the submount 20. In the Y direction, the side on which the laser diode bar 10 is provided may be referred to as the top, upper side, or upper side. The side on which the submount 20 is provided may be referred to as the bottom, lower side, or lower side.

[0020] In addition, in the Z direction, the side of the laser diode bar 10 on which the first end face coating layer 12 is provided may be referred to as the front or front side. The side on which the second end face coating layer (reflective layer) 13 is provided may be referred to as the rear or rear side.

[0021] In this specification, "orthogonal," "parallel," or "the same" means orthogonal, parallel, or the same, including assembly tolerances and processing tolerances of the semiconductor laser device 80 and its components, and does not mean that the objects being compared are orthogonal, parallel, or the same in the strict sense.

[0022] 1 and 2, the semiconductor laser device 80 includes a laser diode bar 10, a submount 20, a first electrode block 31, a second electrode block 32, a microchannel cooler 40 (hereinafter referred to as MCC 40), and a base 50. The semiconductor laser device 80 also includes a laser light shaping unit 70 as an optical member.

[0023] As shown in Fig. 3, the laser diode bar 10 has emitters 11 arranged at intervals along the X direction. The front end face of the laser diode bar 10 is covered with a first end face coating layer 12. The rear end face of the laser diode bar 10 is covered with a second end face coating layer 13. The first end face coating layer 12 is a layer that absorbs laser light LB E The second end face coating layer (reflective layer) 13 is adjusted to have a reflectance of several percent or less with respect to the laser light LB. E When the emitter 11 oscillates, the first end face coating layer 12 emits laser light LB E is emitted forward.

[0024] As shown in FIG. 3, the laser beams LB emitted from the emitters 11 of the laser diode bar 10 are EIn the laser diode bar 10, the cross section cut by a virtual plane perpendicular to the optical axis at a location more than a predetermined distance away (also called a far field pattern (FFP)) is elliptical. The long axis direction (long diameter direction) of this ellipse is called the fast axis direction. Note that the fast axis and the laser beam LB E The direction perpendicular to the optical axis of each of the ellipses is called the slow axis direction (the short axis direction (minor diameter direction) of the ellipse). The fast axis is an axis perpendicular to the pn junction (not shown) formed in the laser diode bar 10, and the slow axis is an axis parallel to the pn junction.

[0025] The submount 20 is a plate-shaped conductive member, and is bonded to the upper surface of the extension portion 32a of the second electrode block 32 by a conductive adhesive (not shown) such as Au-Sn solder. The material of the submount 20 is made of a composite material of diamond and metal, or a conductive semiconductor material such as SiC, and it is preferable that the linear expansion coefficient is close to that of the semiconductor material constituting the laser diode bar 10 and that the Young's modulus is high.

[0026] The first electrode block 31 is disposed behind the laser diode bar 10 and the submount 20 at a distance from them along the Z direction. As shown in Fig. 2, the first electrode block 31 is disposed on the upper surface of the extension portion 32a of the second electrode block 32 via an insulating sheet 33. The first electrode block 31 is connected to the laser diode bar 10 by a plurality of wires 60.

[0027] The second electrode block 32 is disposed behind the first electrode block 31 with a gap therebetween along the Z direction. As described above, the second electrode block 32 is insulated from the first electrode block 31 via the insulating sheet 33. Meanwhile, the extension portion 32a of the second electrode block 32 and the submount 20 are electrically connected to the laser diode bar 10 via a conductive adhesive material (not shown). When a voltage of a predetermined value or more is applied between the first electrode block 31 and the second electrode block 32 from an external power source (not shown), each of the multiple emitters 11 oscillates, and laser light LB is emitted. E is emitted forward.

[0028] The MCC 40 is a plate-like member having a cooling water passage 41 therein. The MCC 40 also has a main body 42 made of metal and two insulating plates 43. The insulating plates 43 insulate the base 50 from the MCC 40, and also insulate the main body 42 from the extension portion 32a. When cooling water is supplied to the MCC 40 from a cooling water supply mechanism (not shown), the cooling water circulates in the cooling water passage 41. At this time, the submount 20 and the laser diode bar 10 above the cooling water passage 41 are cooled, and the temperature of the laser diode bar 10 during operation is maintained within an appropriate range.

[0029] The MCC 40 also supports the first electrode block 31 and the second electrode block 32. The MCC 40 also supports the submount 20 and the laser diode bar 10 mounted on the extension portion 32a of the second electrode block 32.

[0030] The base 50 is a plate-like metal member that supports the MCC 40. The base 50 may also be provided with a cooling water passage (not shown) inside.

[0031] As shown in FIG. 2, the laser light shaping unit 70 has a first holder 71, a second holder 72, an FAC lens array 73, and a beam twister array 74.

[0032] The first holder 71 and the second holder 72 are both irradiated with a laser beam LB EThe laser beam shaping unit 70 is a member made of a material that transmits light, for example, synthetic quartz. The first holder 71 and the second holder 72 hold the FAC lens array (collimator lens array) 73 and the beam twister array 74 so as to sandwich them in the Y direction. As shown in FIG. 2, the second holder 72 is attached to the MCC 40 via a first adhesive 75. The FAC lens array 73 and the beam twister array 74 are attached to the second holder 72, and the first holder 71 is attached to them via these. That is, the laser beam shaping unit 70 is attached to the MCC 40 via the first adhesive 75.

[0033] The thickness L1 of the first adhesive 75 in the Z direction is set so that the distance between the emission point of the laser beam LBE in the emitter 11 and the center of the collimator lens 73a is the working distance WD of the collimator lens 73a. In the example shown in FIG. 2, the thickness L1 is the same as the working distance WD.

[0034] 4, the FAC lens array 73 is an optical member in which a collimator lens 73a having a longitudinal direction and a frame portion 73b provided above and below the lens are integrated. E After passing through the collimator lens 73a, the spread in the fast axis direction is collimated. In other words, the collimator lens 73a is a kind of collimator lens. Note that, instead of the collimator lens 73a, multiple collimator lenses may be arranged for each emitter 11.

[0035] 5, the beam twister array 74 is an optical member in which a plurality of beam twisters 74a are integrated in an array corresponding to the plurality of emitters 11. The longitudinal direction of the beam twister array 74 is the same as the longitudinal direction of the FAC lens array 73. The beam twister 74a is arranged to rotate the laser light LB E The cylindrical lens has an entrance surface on which the laser beam LBE enters and an exit surface from which the laser beam LBE exits, each of which is a convex surface having the same curvature. Note that the number of beam twisters 74a shown in FIG.

[0036] Laser light LB transmitted through the FAC lens array 73 E The laser light LB is rotated by 90 degrees by passing through the beam twister array 74. E The FAC lens array 73 is disposed behind the FAC lens array 73 at a distance from the FAC lens array 73 in the Z direction, which is the traveling direction of the laser beam.

[0037] 2, with respect to the first surface 72a of the second holder 72, a height H1 in the Y direction of the FAC lens array 73 is lower than a height H2 in the Y direction of the beam twister array 74. In this embodiment, the first surface 72a of the second holder 72 is the upper surface of the second holder 72.

[0038] Further, the upper surface of the beam twister array 74 is adhered to the second surface 71a of the first holder 71, and the lower surface of the beam twister array 74 is adhered to the first surface 72a of the second holder 72 by the second adhesive 76. That is, the beam twister array 74 is sandwiched and held and fixed between the first holder 71 and the second holder 72. In this embodiment, the second surface 71a of the first holder 71 is the lower surface of the first holder 71.

[0039] Meanwhile, the lower surface of the FAC lens array 73 is adhered to the first surface 72a of the second holder 72 by a third adhesive 77, but the upper surface is not adhered to the second surface 71a of the first holder 71. Note that, as will be described later, a specific portion on the upper surface of the FAC lens array 73 may be adhered to the second surface 71a of the first holder 71.

[0040] Although not shown, the outer edge of the FAC lens array 73 is adhered to the outer edge of the beam twister array 74 by an adhesive material, not shown. The distance between the surface of the beam twister array 74 facing the FAC lens array 73 and the apex of the collimator lens 73a of the FAC lens array 73 is about several tens of μm, and about 20 μm in this embodiment.

[0041] In this embodiment, the first to third adhesives 75 to 77 are photocurable adhesives, for example, the first to third adhesives 75 to 77 are mainly made of ultraviolet curable resin.

[0042] [Effects, etc.] As described above, the laser light shaping unit 70 of this embodiment is an optical component that includes an FAC lens array (collimator lens array) 73, a beam twister array 74, and a first holder 71 and a second holder 72 that hold the FAC lens array 73 and the beam twister array 74.

[0043] Laser light LB entering the laser light shaping unit 70 E Direction of travel and laser light LB E The direction perpendicular to each of the fast axis directions is defined as the slow axis direction.

[0044] The FAC lens array 73 reflects the incident laser light LB E As described above, the FAC lens array 73 is a member including a collimator lens 73a that collimates the spread of the laser light LB in the fast axis direction and has a longitudinal direction in the slow axis direction. E The light source may be an integrated member in which a plurality of collimating lenses that collimate the expansion of the light in the fast axis direction are arranged along the slow axis direction.

[0045] The beam twister array 74 transmits the laser light LB E The beam twister array 74 is disposed along the traveling direction of the beam and spaced from the FAC lens array 73. Although not shown, the outer edge of the FAC lens array 73 is adhered to the outer edge of the beam twister array 74 by an adhesive material, not shown.

[0046] The beam twister array 74 transmits the laser light LB collimated by the collimator lens 73a. E 90°。 Beam twister 74a is a member in which a plurality of beam twisters 74a are arranged along the slow axis direction and integrated.

[0047] A first holder 71 and a second holder 72 arranged at an interval along the fast axis direction, in this case the Y direction, hold an FAC lens array 73 and a beam twister array 74 so as to sandwich them.

[0048] The FAC lens array 73 and the beam twister array 74 are installed on a first surface 72a of the second holder 72. With the first surface 72a of the second holder 72 as a reference, a height H1 of the FAC lens array 73 in the first axis direction is lower than a height H2 of the beam twister array 74 in the first axis direction.

[0049] By configuring the laser light shaping unit 70 in this way, the incident laser light LB E The laser beam shaping unit 70 can be correctly installed with respect to the optical axis of the laser beam LB. E The optical axis of the collimator lens 73a can be arranged without being tilted beyond an allowable range with respect to the optical axis of the laser beam shaping unit 70. Furthermore, according to this embodiment, the mounting strength of the laser beam shaping unit 70 to the MCC 40, which is a support member, can be ensured. These points will be further described with reference to the drawings.

[0050] Fig. 6 is a schematic diagram of a laser light shaping unit for explaining a first technical problem that occurs in assembling the laser light shaping unit. Fig. 7 is a schematic diagram of a laser light shaping unit for explaining a second technical problem that occurs in assembling the laser light shaping unit. Fig. 8 is a diagram equivalent to Fig. 2 for explaining a technical problem that occurs in assembling a semiconductor laser device.

[0051] For ease of explanation, the MCC 40 and the first to third adhesives 75 to 77 are omitted in Fig. 6 and Fig. 7. Moreover, in Fig. 8, the internal structure of the MCC 40 and the wires 60 connected to the laser diode bar 10 are omitted to show a simplified semiconductor laser device 80. Moreover, the second adhesive 76 and the third adhesive 77 are omitted.

[0052] Usually, the FAC lens array 73 and the beam twister array 74 are molded to have the same height. However, due to variations in processing, the height of the FAC lens array 73 in the Y direction may become higher than the height of the beam twister array 74 in the Y direction, as shown in FIG. 6. When the laser light shaping unit 70 is assembled using the FAC lens array 73 and the beam twister array 74 having such a relationship, the following technical problems may occur. First, as shown in FIG. 6, the first surface 72a of the second holder 72 may be inclined with respect to the second surface 71a of the first holder 71.

[0053] In addition, while the height of FAC lens array 73 in the Y direction is approximately 0.4 mm to several mm, the thickness in the Z direction is approximately 100 μm to 200 μm. Therefore, due to the pressure applied during assembly, FAC lens array 73 may bend and deform so as to protrude in the Z direction, as shown in FIG. 7.

[0054] In either state shown in FIG. 6 or FIG. 7, when the side surface of the second holder 72 is attached to the side surface of the MCC 40 via the first adhesive material 75, as shown in FIG. 8, the laser light LB E With respect to the optical axis of the FAC lens array 73, more specifically, the optical axis LA of the collimating lens 73a C 8 illustrates a case where the laser light shaping unit 70 in the state shown in FIG.

[0055] In this case, the laser light LB E With respect to the optical axis of the collimator lens 73a, the optical axis LA C Since the laser beam LB is inclined, E It becomes difficult to keep the spread within a desired range.

[0056] Also, as shown in FIG. 8, when the first holder 71 is positioned in front of the second holder 72, the distance between the emission point of the laser beam LBE in the emitter 11 and the center of the collimating lens 73a becomes different from the working distance WD of the collimating lens 73a. In the example shown in FIG. 8, the distance between the emission point of the laser beam LBE in the emitter 11 and the center of the collimating lens 73a becomes shorter than the working distance WD of the collimating lens 73a. In order to correct this, it is conceivable to set the thickness of the first adhesive 75 in the Z direction to L2 (>L1).

[0057] However, if the thickness of the first adhesive 75 in the Z direction is increased, the adhesive strength will decrease, and there is a risk that the laser beam shaping unit 70 will fall off from the MCC 40.

[0058] On the other hand, in FIG. 8, when the laser beam shaping unit 70 shown in FIG. 6 is attached, the distance between the emission point of the laser beam LBE in the emitter 11 and the center of the collimating lens 73a becomes longer than the working distance WD of the collimating lens 73a. In order to correct this, it is conceivable to set the thickness of the first adhesive 75 in the Z direction to L2 (<L1).

[0059] However, if the thickness of the first adhesive 75 in the Z direction is decreased, the shear load will be excessively applied to the second holder 72, and there is a risk that cracks or the like will occur in the second holder 72. Also in this case, there is a risk that the laser beam shaping unit 70 will fall off from the MCC 40.

[0060] On the other hand, according to the present embodiment, with reference to the first surface 72a of the second holder 72, which is the installation surface of the FAC lens array 73 and the beam twister array 74, the height H1 of the FAC lens array 73 is made lower than the height H2 of the beam twister array 74.

[0061] By doing so, it is possible to suppress the FAC lens array 73 from protruding and bending in the Z direction. Also, in the Z direction, the positions of the first holder 71 and the second holder 72 can be properly maintained. As a result of these things, the laser beam LBE With respect to the optical axis of the collimator lens 73a, the optical axis LA C The laser beam LB in the fast axis direction can be prevented from tilting beyond the allowable range. E The spread of the light can be suppressed within a desired range.

[0062] Furthermore, according to this embodiment, it is possible to prevent the distance between the emission point of the laser light LBE in the emitter 11 and the center of the collimator lens 73a from being different from the working distance WD of the collimator lens 73a. This makes it possible to prevent the adhesive strength of the first adhesive 75 from decreasing and the second holder 72 from cracking. As a result, it is possible to ensure the attachment strength of the laser light shaping unit 70 to the MCC 40, which is the support member.

[0063] Moreover, the semiconductor laser device 80 according to this embodiment includes at least a laser light shaping unit 70, a laser diode bar 10, and an MCC (support member) 40. The laser diode bar 10 emits laser light LB E The MCC 40 has a plurality of emitters 11 that emit light. The MCC 40 supports the laser diode bar 10 via a submount 20.

[0064] The second holder 72 is adhered to a side surface of the MCC 40 via a first adhesive 75, whereby the laser light shaping unit 70 is attached to the MCC 40.

[0065] Laser light LB emitted from a plurality of emitters 11 E By transmitting through the FAC lens array 73 and the beam twister array 74, each of the beams is parallelized from its spread in the fast axis direction and rotated by 90° immediately after being emitted from the multiple emitters 11.

[0066] By configuring the semiconductor laser device 80 in this manner, the laser light LB emitted from the multiple emitters 11 E In each of the above, the laser beam LB in the first axis direction EThe spread of each laser beam LB can be suppressed to a desired range. E By doing so, the laser beam LB can be rotated by 90 degrees. E A single combined laser beam LB M (See FIG. 10.) In addition, it is easy to combine the multiple laser beams LB E A single combined laser beam LB M The manner in which the molecule is bound to the nucleotide will be described later.

[0067] In this embodiment, the laser light source is a laser diode bar 10 having a plurality of emitters 11, but the laser light source may be a laser diode having a single emitter. In this case, a single collimator lens is used instead of the FAC lens array 73, and a single beam twister is used instead of the beam twister array 74.

[0068] That is, the laser light shaping unit 70 may be an optical member including a collimating lens, a beam twister, and a first holder 71 and a second holder 72 that hold the collimating lens and the beam twister.

[0069] The collimating lens collimates the incident laser light LB E The expansion in the first axis direction is parallelized.

[0070] The beam twister is a laser beam LB E The beam twister is arranged at a distance from the collimating lens along the direction of laser light LB. E Rotate by 90 degrees.

[0071] A first holder 71 and a second holder 72 arranged at an interval along the fast axis direction hold the collimator lens and the beam twister so as to sandwich them.

[0072] The collimator lens and the beam twister are disposed on the first surface 72a of the second holder 72. With the first surface 72a of the second holder 72 as a reference, the height of the collimator lens in the fast axis direction is lower than the height of the beam twister in the fast axis direction.

[0073] In this case too, the incident laser light LB E The laser beam shaping unit 70 can be correctly installed with respect to the optical axis of the laser beam LB. E The optical axis of the collimator lens can be arranged without being tilted beyond an allowable range with respect to the optical axis of the laser beam shaping unit 70. Also, the mounting strength of the laser beam shaping unit 70 to the MCC 40, which is a supporting member, can be ensured.

[0074] The semiconductor laser device 80 includes a laser light shaping unit 70 and a laser light LB E and an MCC 40 that supports the laser diode via a submount 20.

[0075] The second holder 72 is adhered to a side surface of the MCC 40 via a first adhesive 75, whereby the laser light shaping unit 70 is attached to the MCC 40.

[0076] Laser light LB E By passing through the collimator lens and the beam twister, the spread in the fast axis direction is collimated and the light is rotated by 90° immediately after being emitted from the laser diode.

[0077] By configuring the semiconductor laser device 80 in this manner, the laser light LB emitted from the laser diode E In the laser beam LB, the spread in the fast axis direction can be suppressed within a desired range. E As a result, when a laser module is configured using a plurality of semiconductor laser devices 80, a plurality of laser beams LB E A single combined laser beam LB M (See FIG. 10)

[0078] <Modification> FIG. 9 is a diagram showing a laser light shaping unit according to a modified example, viewed along the traveling direction of the laser light.

[0079] For ease of explanation, in FIG. 9 and FIG. 10 shown later, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed explanations thereof will be omitted.

[0080] In the example shown in the first embodiment, the upper surface of the FAC lens array 73 is not bonded to the second surface 71a of the first holder 71. However, if the upper surface of the FAC lens array 73 is not fixed, the FAC lens array 73 will tilt, and the laser light LB E With respect to the optical axis of the collimator lens 73a, the optical axis LA C If the amount of this tilt exceeds the allowable range, as described above, the laser beam LB in the fast axis direction may be tilted. E It becomes difficult to keep the spread within a desired range.

[0081] In this modification, a part of the upper surface of the FAC lens array 73 and the second surface 71a of the first holder 71 are bonded with a fourth adhesive 78 to suppress the inclination of the FAC lens array 73, and the laser light LB in the fast axis direction is prevented from being tilted. E The material of the fourth adhesive 78 is the same as that of the first to third adhesives 75 to 77.

[0082] In the example shown in FIG. 9, the lower surface of the beam twister array 74 is bonded to the first surface 72a of the second holder 72 at three locations by the second adhesive 76. The upper surface of the beam twister array 74 is bonded to the second surface 71a of the first holder 71 at two locations by the second adhesive 76. The lower surface of the FAC lens array 73 is bonded to the first surface 72a of the second holder 72 at three locations by the third adhesive 77. However, the arrangement locations and areas of the second adhesive 76 and the third adhesive 77 are not particularly limited thereto. For example, the entire lower surface of the beam twister array 74 may be bonded to the first surface 72a of the second holder 72 by the second adhesive 76, or the entire upper surface may be bonded to the second surface 71a of the first holder 71. The second adhesive 76 may be provided on both the upper and lower surfaces of the beam twister array 74. Also, a second adhesive 76 may be provided in a region overlapping with the laser diode bar 10 when viewed from the Z direction (the range indicated by W in FIG. 9). Also, the entire lower surface of the FAC lens array 73 may be adhered to the first surface 72a of the second holder 72 by a third adhesive 77.

[0083] Further, the upper surface of the FAC lens array 73 is adhered to the second surface 71a of the first holder 71 at two points by a fourth adhesive 78. When viewed from the Z direction, these adhesion points are disposed outside the laser diode bar 10. In Fig. 9, the fourth adhesive 78 is disposed outside the arrow indicated by the width W.

[0084] If the fourth adhesive 78 is disposed on the inside of the laser diode bar 10, the laser light LB E is the optical axis LA of the collimating lens 73a. C There is a risk that the fourth adhesive 78 will be irradiated with a slight deviation from the intended position. In this case, the fourth adhesive 78 may deteriorate and deform, causing the position of the FAC lens array 73 to deviate from the desired position.

[0085] On the other hand, according to this modification, the laser diode is not disposed inside the laser diode bar 10. In other words, at least the laser light LB EIn the region where the laser light LB passes through, the fourth adhesive 78 is not in contact with the second surface 71a of the first holder 71. In this manner, the laser light LB E is the optical axis LA of the collimating lens 73a. C Even if it deviates from the target, the laser light LB E is not irradiated onto the fourth adhesive 78. This makes it possible to prevent the fourth adhesive 78 from deteriorating or deforming, causing the FAC lens array 73 to shift from a desired position, or in an extreme case, to fall off from the second holder 72.

[0086] From this viewpoint, the upper surface of the beam twister array 74 and the second surface 71a of the first holder 71 are in contact with each other so that at least the laser light LB E It is preferable that the light-transmitting regions are not in contact with each other.

[0087] However, the upper surface of the beam twister array 74 is closer to the second surface 71a of the first holder 71 than the upper surface of the FAC lens array 73. E is the optical axis LA of the collimating lens 73a. C Even if the laser beam LB is slightly deviated from the E The possibility that the second adhesive material 76 is irradiated with the fourth adhesive material 78 is lower than that of the fourth adhesive material 78. Therefore, as described above, the second adhesive material 76 may be provided on the entire upper surface of the beam twister array 74.

[0088] As described in the first embodiment, the laser light shaping unit 70 may be an optical member including a collimating lens, a beam twister, and a first holder 71 and a second holder 72 for holding the collimating lens and the beam twister. In this case, the beam twister is bonded to a first surface 72a of the second holder 72 and a second surface 71a of the first holder 71 via a second adhesive 76.

[0089] The collimator lens is bonded to the first surface 72a of the second holder 72 via a third adhesive 77, while at least the laser light LB E The area through which the laser light LB passes is not in contact with the second surface 71a of the first holder 71.E A collimating lens may be bonded to the first surface 72a of the second holder 72 via a fourth adhesive 78 outside the region through which the light passes.

[0090] (Embodiment 2) FIG. 10 is a schematic diagram of the inside of the laser module according to the second embodiment.

[0091] The laser module 120 includes a plurality of semiconductor laser devices 80, a diffraction grating 90, an external cavity mirror 100, and a housing 110. The laser module 120 shown in FIG. 10 includes a plurality of other members in addition to the above-mentioned members, such as a laser beam LB E In addition, the number of semiconductor laser devices 80 is different from the actual number.

[0092] 10, a plurality of semiconductor laser devices 80, a diffraction grating 90, and an external cavity mirror 100 are arranged inside a housing 110 while maintaining a predetermined positional relationship with each other. The external cavity mirror 100 is provided in the housing 110, covering a light exit window (not shown) provided in the housing 110. The external cavity mirror 100 may be provided inside the housing 110, between the diffraction grating 90 and the light exit window.

[0093] In one semiconductor laser device 80, a plurality of laser beams LB are emitted from a plurality of emitters 11. E are shaped by the laser light shaping unit 70 and their rotation directions are changed, and then travel toward the diffraction grating 90 while maintaining a mutually parallel relationship.

[0094] The diffraction grating 90 reflects a plurality of laser beams LB E Each laser beam LB E is diffracted and directed towards the external cavity mirror 100.

[0095] At this time, the diffraction grating 90 reflects each laser beam LB EThe optical axes of the laser beams LB are close to each other and parallel to each other. E are diffracted, respectively.

[0096] The external cavity mirror 100 reflects the incident laser beams LB E 1 and 2. The external cavity mirror 100 transmits a part of the laser diode bars 10 and reflects the remaining part toward the diffraction grating 90. In this manner, an external cavity is formed between the external cavity mirror 100 and each of the laser diode bars 10. This will be described in further detail below.

[0097] Each laser beam LB emitted from the laser diode bar 10 E After being diffracted by the diffraction grating 90, the laser light LB is incident on the external cavity mirror 100. E A part of the laser light LB is transmitted through the diffraction grating 90, while the remaining part is reflected toward the diffraction grating 90 and then returns to the laser diode bar 10. Most of this reflected return light passes through the first end face coating layer 12 of the laser diode bar 10 and reaches the second end face coating layer (reflective layer) 13. E is reflected by the second end face coating layer 13 and emitted again to the outside of the laser diode bar 10 from the first end face coating layer 12.

[0098] Laser light LB emitted from each emitter 11 of the laser diode bar 10 E Of these, only light having a wavelength (hereinafter referred to as a lock wavelength) that satisfies the diffraction condition of the diffraction grating 90 and is reflected by the external cavity mirror 100 is fed back to the original emitter 11, thereby forming an external cavity between the second end face coating layer 13 of the laser diode bar 10 and the external cavity mirror 100, and laser light LB is emitted from the laser diode bar 10, specifically, from each of the multiple emitters 11. E will be output.

[0099] The lock wavelength of each emitter 11 is λ L , the period of the diffraction grating 90 is d, the angle of incidence is α, the angle of emergence is β, and the order is m, then the lock wavelength λ L is expressed by equation (1).

[0100] d(sinα+sinβ)=mλ L ...(1) Generally, the order of the diffraction grating 90 is m=1.

[0101] For example, in the laser diode bar 10, the emitters 11 are formed so that the incident angle α with respect to the incident surface of the diffraction grating 90 changes for each position of the emitters 11. In this case, the lock wavelength of the emitters 11 formed in the laser diode bar 10 changes stepwise from one end of the laser diode bar 10 to the other end.

[0102] Each emitter 11 can oscillate by external resonance only when the inherent gain wavelength intensity of the laser diode bar 10 is equal to or greater than a predetermined value. g Therefore, the laser module 120 of this embodiment oscillates at a lock wavelength within a predetermined range and does not oscillate at a lock wavelength outside the predetermined range. g The upper and lower limit ranges are the lock wavelengths λ of the emitters 11 at both ends of the laser diode bar 10. L Difference Δλ L_bar The optical design of the laser diode bar 10 and each emitter 11 is performed so that the lock wavelength λ of the emitters 11 at both ends falls within the range. L Difference Δλ L_bar varies with the distance between the laser diode bar 10 and the diffraction grating 90.

[0103] Laser light LB emitted from each emitter 11 of the laser diode bar 10 E The positional relationship between the laser diode bar 10 and the diffraction grating 90 is defined so that the optical axes of the laser beams LB 10 and LB 20 overlap each other when they pass through the diffraction grating 90. E are made to overlap each other when they are incident on the external cavity mirror 100. In this way, the multiple laser beams LBE The laser light LB emitted from each of the multiple emitters 11 provided in the multiple laser modules 120 is superimposed and combined, which is called wavelength synthesis. E There is one combined laser beam (module laser beam LB M ) and is emitted to the outside of the laser module 120.

[0104] The laser module 120 according to this embodiment includes a plurality of semiconductor laser devices 80 and a plurality of laser beams LB emitted from a plurality of emitters 11 and transmitted through a laser beam shaping unit 70. E The laser module 120 includes at least a diffraction grating 90 for coupling the laser light LB E and a housing 110 that houses the semiconductor laser devices 80, the diffraction grating 90, and the external cavity mirror 100.

[0105] The emitter 11 emits laser light LB E A second end face coating layer (reflective layer) having a predetermined reflectance is provided on the surface opposite to the output end face of the optical fiber.

[0106] External cavity mirror 100 and laser light LB E An external resonator is formed between the emitter 11 and the second end face coating layer 13 from which the laser beam is emitted, and a combined laser beam (module laser beam LB M ) is emitted to the outside of the housing 120.

[0107] The FAC lens array 73 parallelizes the spread in the fast axis direction, and the beam twister array 74 rotates the rotation direction by 90 degrees, forming multiple laser beams LB E When the laser beam LB is diffracted by the diffraction grating 90, E As a result, the laser beams LB emitted from the multiple emitters 11 can be overlapped closely with each other. E Combined high power combined laser light (module laser light LB M ) can be obtained.

[0108] In this embodiment, a plurality of laser beams LB E However, the present invention is not limited to this. E Alternatively, another optical element, for example a prism, may be used as the optical coupling element for coupling.

[0109] In addition, the laser module 120 may include one semiconductor laser device 80. In this case, the laser light LB emitted from each of the multiple emitters 11 is E Combined high power combined laser light (module laser light LB M ) can be obtained.

[0110] (Other embodiments) In this specification, the laser light shaping unit 70 is attached to the MCC 40, but the laser light shaping unit 70 may be attached to the side surface of the base 50. In this case, the MCC 40 may be omitted, or the MCC 40 and the base 50 may be integrated. [Industrial Applicability]

[0111] The optical member of the present disclosure is useful because it can be correctly installed with respect to the optical axis of the laser light and the attachment strength to the support member can be ensured. [Explanation of symbols]

[0112] 10 Laser Diode Bar 11 Emitter 12 First end face coating layer 13 Second end face coating layer (reflective layer) 20 Submount 31 First electrode block 32 Second electrode block 32a Extension 33 Insulation sheet 40 Microchannel cooler (support member) 41 Cooling Channel 42 Main body 43 Insulating plate 50 Base (support member) 60 Wire 70 Laser light shaping unit (optical components) 71 First Holder 71a Bottom surface (2nd surface) 72 Second Holder 72a Top surface (first surface) 73 FAC lens array (collimating lens array) 73a Collimating Lens 73b Frame 74 Beam Twister Array 74a Beam Twister 75 1st adhesive material 76 Second adhesive 77 Third adhesive 78 4th Adhesive 80 Semiconductor laser device 90 Diffraction grating (optical coupling element) 100 External cavity mirror 110 Cabinet 120 Laser Module

Claims

1. An optical member comprising: a collimating lens array; a beam twister array; and a first holder and a second holder for holding the collimating lens array and the beam twister array, When a direction perpendicular to each of the traveling direction of the laser light incident on the optical member and the fast axis direction of the laser light is defined as a slow axis direction, the collimator lens array is a member including a collimator lens that collimates the spread of the laser light in the fast axis direction and has a longitudinal direction in the slow axis direction, the beam twister array is disposed at an interval from the collimator lens array along the traveling direction of the laser light, and is an integrated member in which a plurality of beam twisters are disposed along the slow axis direction and rotate the laser light collimated by the collimator lens by 90 degrees; the first holder and the second holder arranged at an interval along the fast axis direction hold the collimator lens array and the beam twister array so as to sandwich them; the collimator lens array and the beam twister array are disposed on a first surface of the second holder; An optical component, characterized in that, with respect to the first surface of the second holder, the height of the collimator lens array in the fast axis direction is lower than the height of the beam twister array in the fast axis direction.

2. The optical member according to claim 1 , the beam twister array is bonded to the first surface and to a second surface of the first holder facing the first surface in the fast axis direction via a second adhesive; An optical component characterized in that the collimating lens array is adhered to the first surface via a third adhesive, but is not in contact with the second surface at least in the area through which the laser light passes.

3. An optical member comprising: a collimating lens; a beam twister; and a first holder and a second holder for holding the collimating lens and the beam twister, The collimator lens collimates the spread of the incident laser light in the fast axis direction, the beam twister is disposed at an interval from the collimator lens along a traveling direction of the laser light, and rotates the laser light collimated by the collimator lens by 90°; the first holder and the second holder are arranged at an interval along the fast axis direction and hold the collimator lens and the beam twister so as to sandwich them; the collimator lens and the beam twister are disposed on a first surface of the second holder; An optical member, characterized in that, with respect to the first surface of the second holder, the height of the collimator lens in the fast axis direction is lower than the height of the beam twister in the fast axis direction.

4. The optical member according to claim 3 , the beam twister is bonded to the first surface and to a second surface of the first holder opposed to the first surface in the fast axis direction via a second adhesive, An optical component characterized in that the collimating lens is adhered to the first surface via a third adhesive, but is not in contact with the second surface at least in the area through which the laser light passes.

5. The optical member according to claim 1 or 2; a laser diode bar having a plurality of emitters each emitting the laser light; A support member on which the laser diode bar is mounted; the second holder is adhered to a side surface of the support member via a first adhesive, thereby attaching the optical member to the support member; a first lens array and a second lens array arranged to be in contact with the first light source and to be rotated by 90 degrees from the first light source to the second light source;

6. The optical member according to claim 3 or 4, a laser diode that emits the laser light; a support member for supporting the laser diode; the second holder is adhered to a side surface of the support member via a first adhesive, thereby attaching the optical member to the support member; a first axis of the laser beam being parallelized by passing through the collimator lens and the beam twister, and being rotated 90 degrees from the point of view immediately after being emitted from the laser diode;

7. A semiconductor laser device according to claim 5 ; an optical coupling element that couples the laser beams emitted from the plurality of emitters and transmitted through the optical member; an external cavity mirror that reflects the laser light coupled by the optical coupling element toward the optical coupling element; a housing that houses one or more of the semiconductor laser devices, the optical coupling element, and the external cavity mirror; the emitter is provided with a reflective layer having a predetermined reflectance on a surface opposite to an output end surface of the laser light, an external resonator is configured between the external resonator mirror and the reflective layer of the emitter from which the laser light is emitted; A laser module, characterized in that a combined laser beam combined by the optical coupling element is emitted to the outside of the housing.

Images