Optical device and method for manufacturing optical device

Abstract

This optical device comprises, e.g.: a plurality of sub-assemblies, each of which has a laser light-emitting element, an optical fiber to which the output light of the laser light-emitting element is coupled, and a sub-mount to which the laser light-emitting element and the optical fiber are attached; and a base to which the plurality of sub-assemblies are attached. The optical device may additionally comprise: a cable that has a plurality of optical fibers extending from the plurality of sub-assemblies, and a tube surrounding the plurality of optical fibers; and a connector to which end portions of the plurality of optical fibers are fixed.

Description

Optical device and method for manufacturing the same

[0001] The present invention relates to an optical device and a method for manufacturing an optical device.

[0002] Conventionally, optical devices have been known that include a laser light-emitting element and an optical fiber to which output light from the laser light-emitting element is coupled (for example, see Patent Document 1). The optical device disclosed in Patent Document 1 includes only one combination of a laser light-emitting element and an optical fiber.

[0003] Japanese Patent Application Laid-Open No. 2004-349294

[0004] In recent years, optical devices equipped with multiple combinations of laser light emitting elements and optical fibers have been developed for use in data centers, for example.

[0005] The inventors have conducted extensive research into the configuration and manufacturing method of such an optical device and have found that if multiple laser light-emitting elements and optical fibers are all directly attached to a common member, various problems may arise, such as the time required to manufacture one optical device being extended because it takes time to adjust the positions of the laser light-emitting elements and optical fibers to increase the coupling efficiency for each combination, and the size of the optical device increasing to avoid interference between the jig used to adjust the positions and the components.

[0006] It is therefore an object of the present invention to provide a novel and improved optical device and method for manufacturing the optical device that can reduce or avoid problems associated with, for example, having multiple combinations of laser light emitting elements and optical fibers.

[0007] The optical device of the present invention comprises, for example, a plurality of subassemblies each having a laser light-emitting element, an optical fiber to which the output light of the laser light-emitting element is coupled, and a submount to which the laser light-emitting element and the optical fiber are attached, and a base to which the plurality of subassemblies are attached.

[0008] The optical device may include a cable having a plurality of optical fibers extending from the plurality of subassemblies and a tube surrounding the plurality of optical fibers, and a connector to which ends of the plurality of optical fibers are fixed.

[0009] In the optical device, the optical fibers of the subassemblies may extend substantially along a first direction on the base and be arranged at intervals in a second direction intersecting the first direction.

[0010] In the optical device, the positions of the plurality of subassemblies on the base in the first direction may be non-uniform.

[0011] The optical device may include two subassemblies adjacent to each other with a gap therebetween, as the two subassemblies adjacent to each other in the second direction.

[0012] The optical device may include a first cover that covers at least the laser light-emitting element and has a light-blocking property.

[0013] In the optical device, the first cover may have a higher thermal conductivity than a gas surrounding the laser light-emitting element.

[0014] In the optical device, the first cover may be thermally connected to the submount.

[0015] The optical device may include a housing that houses the plurality of subassemblies.

[0016] In the optical device, the subassembly may be fixed onto a surface of the base, a wiring portion made of a conductor may be provided on the surface, and the wiring portion and the conductor of the subassembly may be electrically connected via a wire made of a conductor.

[0017] In the optical device, the wiring portion may have a portion that extends substantially along the first direction on the surface.

[0018] The optical device may include a plurality of wires of different lengths as the wires.

[0019] The optical device may include a second cover that covers the wire.

[0020] In the optical device, the laser light-emitting element may output the output light in a first direction, and the submount may have a first portion adjacent to the laser light-emitting element and joined to the base, and a second portion extending from the first portion away from the base and supporting at least the optical fiber.

[0021] In the optical device, the submount and the base may have a higher thermal conductivity than a gas surrounding the laser light-emitting element.

[0022] In the optical device, the optical fiber may be a polarization-maintaining optical fiber.

[0023] A manufacturing method for an optical device of the present invention includes, for example, a first step of producing a plurality of subassemblies each having a laser light-emitting element, an optical fiber to which the output light of the laser light-emitting element is coupled, and a submount to which the laser light-emitting element and the optical fiber are attached, and a second step of attaching the plurality of subassemblies to a base.

[0024] The method for manufacturing the optical device may include a third step, after the first step and before the second step, of fixing ends of a plurality of optical fibers, including the optical fibers extending from the plurality of subassemblies, to a connector body.

[0025] The method for manufacturing the optical device may include a fourth step in which the plurality of optical fibers are polarization-maintaining optical fibers, and the fourth step is performed after the first step and before the third step, to adjust the angle of the end portion relative to the connector body around the central axis.

[0026] SUMMARY OF THE INVENTION In accordance with the present invention, new and improved optical devices and methods for manufacturing optical devices are provided.

[0027] FIG. 1 is an exemplary and schematic perspective view of a communication device including an optical device according to a first embodiment. FIG. 2 is an exemplary and schematic perspective view showing the internal configuration of the optical device according to the first embodiment. FIG. 3 is an exemplary and schematic plan view showing the internal configuration of the optical device according to the first embodiment. FIG. 4 is an exemplary and schematic perspective view of the IV-IV cross section of FIG. 3. FIG. 5 is an exemplary and schematic plan view of a portion of a subassembly included in the optical device according to the first embodiment. FIG. 6 is a flowchart showing an example of the steps of a manufacturing method for the optical device according to the first embodiment. FIG. 7 is an exemplary front view showing a portion of an array of optical fibers at an end of a connector of the optical device according to the first embodiment. FIG. 8 is an exemplary and schematic perspective view of a cross section of an optical device according to a second embodiment taken at a position equivalent to that shown in FIG. 4. FIG. 9 is an exemplary and schematic perspective view of a cross section of an optical device according to a third embodiment taken at a position equivalent to that shown in FIG. 4.

[0028] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions and results (effects) brought about by the configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

[0029] The following embodiments have similar configurations. Therefore, according to the configurations of each embodiment, similar actions and effects based on the similar configurations can be obtained. Furthermore, in the following, similar configurations are given similar reference numerals, and duplicated descriptions may be omitted.

[0030] In this specification, ordinal numbers are given for convenience to distinguish directions, members, parts, etc., and do not indicate priority or order.

[0031] In each figure, the X direction is represented by an arrow X, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X direction, Y direction, and Z direction intersect with each other and are perpendicular to each other. The X direction can also be referred to as the longitudinal direction or extension direction, the Y direction can also be referred to as the lateral direction or width direction, and the Z direction can also be referred to as the thickness direction or height direction.

[0032] [First embodiment] [Structure of optical module] Fig. 1 is a perspective view of a communication device 10 according to a first embodiment. As shown in Fig. 1, the communication device 10 includes an optical module 100, a connector module 200, and an optical fiber cable 300. The communication device 10 may also be referred to as an optical communication device.

[0033] The optical fiber cable 300 includes a plurality of optical fibers 301 and a tube 302 that bundles and surrounds the plurality of optical fibers 301. The plurality of optical fibers 301 extend between the interior of the optical module 100 and the interior of the connector module 200.

[0034] The connector module 200 has a connector body 201. A plurality of optical fibers 301 are fixed to the connector body 201, for example, via an adhesive.

[0035] The optical module 100 has a base 101 and an FPC 103 (flexible printed circuit). Note that only a portion of the optical module 100 is shown in Fig. 1. The optical module 100 also includes a PCBA (printed circuit board assembly) connected to the FPC 103, a controller mounted on the PCBA, a power supply unit, an outer boot that covers the connection portion between the optical fiber 301 and the optical module 100, an outer case, and the like (none of which are shown). The optical module 100 is an example of an optical device.

[0036] 2 and 3 are diagrams showing the internal configuration of the portion of the optical module 100 shown in FIG. 1, with FIG. 2 being a perspective view of that portion and FIG. 3 being a plan view of that portion.

[0037] 2 and 3 , the optical module 100 includes a base 101, an FPC 103, and a plurality of subassemblies 110. The plurality of subassemblies 110 are housed in a space (a housing) surrounded by the base 101 and an outer cover (not shown). In other words, the base 101 and the outer cover form a housing for the optical module 100.

[0038] The base 101 has a rectangular, plate-like shape, a substantially constant thickness in the Z direction, and extends perpendicularly to and intersects the Z direction. The base 101 also has a surface 101a. The surface 101a faces the Z direction at an end in the Z direction, and extends perpendicularly to and intersects the Z direction.

[0039] A plurality of subassemblies 110 are attached to the surface 101a by a bonding material (not shown), such as an adhesive or solder. In order to transfer heat generated in the subassemblies 110 to the base 101, the thermal conductivity of the bonding material is preferably higher than that of the gas surrounding the subassemblies 110 and the base 101. For example, the bonding material may contain a filler made of a substance with a relatively high thermal conductivity.

[0040] Each subassembly 110 has a substantially constant width in the Y direction and a substantially constant height in the Z direction, and extends in the X direction. An optical fiber 301 extends from each subassembly 110. In the optical module 100, the number of subassemblies 110 is the same as the number of optical fibers 301. The multiple optical fibers 301 extend substantially along the X direction on the surface 101a of the base 101. The multiple optical fibers 301 are also arranged at substantially constant intervals from one another in the Y direction. The X direction is an example of a first direction, and the Y direction is an example of a second direction.

[0041] 2 and 3, in this embodiment, the attachment positions of the multiple subassemblies 110 to the base 101 in the X direction are not uniform. That is, in this embodiment, it is not necessary to strictly align the lengths of the optical fibers 301 between the connector module 200 and the subassembly 110.

[0042] Fig. 4 is a perspective view showing a cross section taken along line IV-IV in Fig. 3. As shown in Fig. 4, the subassembly 110A (110) has a submount 111, a laser light emitting element 112, a lens 115, an isolator 116, a support member 117 that supports the optical fiber 301, and a photodiode 120.

[0043] The laser light-emitting element 112 is, for example, a semiconductor laser element. An electrode 113 is provided on the submount 111. The laser light-emitting element 112 and the electrode 113 are electrically connected via a wire 114a made of a conductor. Furthermore, a plurality of conductive wirings 101a1 and insulating regions 101a2 between the wirings 101a1 are provided on the surface 101a of the base 101. The electrode 113 and the wirings 101a1 are electrically connected via a conductive wire 114b. Furthermore, the wirings 101a1 are electrically connected to wirings (not shown) provided on the FPC 103, which are electrically connected to a power source (not shown). In this configuration, the laser light-emitting element 112 emits light in response to power supplied from the power source via the wirings of the FPC 103, the wirings 101a1 on the surface 101a of the base 101, the wires 114b, the electrode 113, and the wires 114a. The wiring 101a1 is an example of a wiring portion.

[0044] The laser light (output light) output from the laser light-emitting element 112 is transmitted to the end 301e1 of the optical fiber 301 via the lens 115 and the isolator 116, and is coupled to the end 301e1. The lens 115 and the isolator 116 are examples of optical components. Note that optical components other than the lens 115 and the isolator 116 may be provided between the laser light-emitting element 112 and the optical fiber 301. Alternatively, instead of providing the lens 115, the optical fiber 301 may be configured as a lensed fiber. In this case, the isolator 116 may not be provided.

[0045] The photodiode 120 detects the intensity of the output light from the laser light emitting element 112. An intensity signal detected by the photodiode 120 is transmitted to the controller via the wire 114b, the wiring 101a1, and the wiring of the FPC 103.

[0046] The optical fiber 301 is attached to the support member 117 via an adhesive (not shown). In addition, an adhesive 118 is provided on the support member 117 around the optical fiber 301 to fix the optical fiber 301 to the support member 117.

[0047] The submount 111 extends in the X direction with a substantially constant width in the Y direction. The height of the submount 111 in the Z direction varies depending on the position in the X direction. That is, the submount 111 has a step. The submount 111 is made of a ceramic (material) with a relatively high thermal conductivity, such as aluminum nitride. The submount 111 may also be configured as a silicon optical bench (SiOB), for example.

[0048] The laser light emitting element 112, lens 115, isolator 116, and support member 117 are attached to the submount 111 via an adhesive 119. The optical fiber 301 is attached to the support member 117 via an adhesive (not shown). That is, the optical fiber 301 is attached to the submount 111 via the support member 117 and the like. Furthermore, the laser light emitting element 112 and the photodiode 120 are attached to the submount 111 via, for example, solder. Adhesive and solder are examples of bonding materials.

[0049] The subassembly 110 also has a cover 130. The cover 130 covers the components of the subassembly 110 other than the cover 130, such as the laser light-emitting element 112, the lens 115, the isolator 116, a portion of the optical fiber 301 including the end 301e1, the photodiode 120, and the wires 114a and 114b. The cover 130 is attached to the submount 111.

[0050] 2 to 4 , the cover 130 has multiple members, specifically, a first member 131, a second member 132, and a boot 133. The first member 131 covers the laser light-emitting element 112, the lens 115, the isolator 116, the optical fiber 301, the wire 114a, and the photodiode 120 on the surface 101a of the base 101. Openings are provided in the first member 131 at its end in the X direction and at its end opposite the X direction. The second member 132 covers the opening at the end of the first member 131 in the X direction and also covers the wire 114b. The boot 133 closes the opening at the end of the first member 131 opposite the X direction. The optical fiber 301 passes through the boot 133. With this configuration, for example, with the first member 131 and the boot 133 attached to the submount 111 and the second member 132 not attached to the submount 111, the wire 114b and the wiring 101a1 can be bonded while avoiding interference with the cover 130 of a bonding device (not shown). If the cover 130 were composed of a single member, the entire cover 130 would have to be removed from the submount 111, exposing the components, at least during the bonding operation, which could reduce the protection of the components. In this regard, in the present embodiment, the bonding operation can be performed with the first member 131 and the boot 133 attached to the submount 111 to cover the components, and with the second member 132 not attached to the submount 111, exposing the wire 114a. This allows the wire 114b and the wiring 101a1 to be bonded smoothly while avoiding interference with the cover 130 of the bonding device and while ensuring protection of the components. Furthermore, by forming the first member 131 and the boot 133 as separate members, the boot 133 can be made of, for example, an elastic material that is softer and more flexible than the first member 131. This ensures a higher level of sealing in the gap between the boot 133 and the optical fiber 301, while ensuring higher protection for the components by the first member 131 having higher rigidity than the boot 133. The first member 131 and the boot 133 are an example of a first cover, and the second member 132 is an example of a second cover.Note that the openings at both ends of the first member 131 may be sealed by providing a resin material with a relatively low elastic modulus instead of the second member 132 and the boot 133. In this case, the resin material is an example of a second cover.

[0051] Furthermore, at least a portion of the cover 130 is made of a material with a higher thermal conductivity than at least the gas (e.g., air, inert gas, etc.) surrounding the laser light-emitting element 112 and the submount 111 so as to serve as a heat transfer path (heat dissipation path) for heat generated by the laser light-emitting element 112 as a heat-generating element, and at least a portion of the cover 130 is thermally connected to the submount 111 and the laser light-emitting element 112. Specifically, for example, the first member 131 and the second member 132 are made of a metal material with a relatively high thermal conductivity, such as an aluminum-based material such as pure aluminum or an aluminum alloy, or a copper-based material such as oxygen-free copper or a copper alloy. For example, the first member 131 is attached to the submount 111 with a bonding material or a fastener, and the second member 132 is attached to the first member 131 or the submount 111 with a bonding material or a fastener. The submount 111 is thermally connected to the laser light-emitting element 112. The first member 131 is thermally connected to the submount 111, and is therefore thermally connected to the laser light-emitting element 112. The second member 132 is thermally connected to the first member 131 or the submount 111, and is therefore thermally connected to the laser light-emitting element 112.

[0052] Furthermore, a thermally conductive sheet 140 is interposed between the cover 130 and the outer cover. The thermally conductive sheet 140 is made of a material that is softer, more flexible, and more elastic than the cover 130 and the outer cover, and is in close contact with both. The outer cover is also made of a material with a thermal conductivity higher than that of the gas surrounding at least the laser light-emitting element 112 and the submount 111. Specifically, the outer cover is made of a metal material with a relatively high thermal conductivity, such as an aluminum-based material such as pure aluminum or an aluminum alloy, or a copper-based material such as oxygen-free copper or a copper alloy. Therefore, heat generated by the laser light-emitting element 112 is transferred to the outer cover via the cover 130 and the thermally conductive sheet 140 and then dissipated from the outer cover. Therefore, according to this embodiment, heat dissipation from the subassembly 110 is improved, thereby preventing the temperature of the laser light-emitting element 112 or other components from rising, which could make it difficult to achieve the desired optical characteristics and reliability. The thermally conductive sheet 140 is an example of a heat transfer member. The outer cover may be provided with a heat dissipation structure such as a heat sink including multiple fins or multiple pins.

[0053] At least a part of the cover 130, in this embodiment, the entire cover 130, i.e., the first member 131, the second member 132, and the boot 133, is made of a material that blocks the output light of the laser light-emitting element 112. This makes it possible to prevent unwanted light (stray light) from leaking out of the subassembly 110.

[0054] 3 and 4, the wiring 101a1 extends long in the X direction on the surface 101a of the base 101. Therefore, as shown in Fig. 4, the wire 114b can be joined to any position on the wiring 101a1 within a predetermined range along which the wiring 101a1 extends. Therefore, within the predetermined range along which the wiring 101a1 extends, electrical connection between the wiring 101a1 and the laser light-emitting element 112 or the photodiode 120 can be relatively easily ensured by the wire 114b of a predetermined length, regardless of the position of the subassembly 110 in the X direction.

[0055] 5 is a plan view of a portion of the optical module 100, showing only the first member 131 of the cover 130. As shown in FIG. 5, adjacent first members 131 in the Y direction, and therefore adjacent subassemblies 110, are not in contact with each other but are separated by a gap g. This prevents heat generated in the laser light-emitting element 112 from adversely affecting the desired optical characteristics and reliability of the laser light-emitting element 112 or other components included in a subassembly 110 other than the subassembly 110 containing the laser light-emitting element 112. A heat insulating material with a lower thermal conductivity than the gas surrounding the first member 131 and the submount 111 may be interposed between the two first members 131, i.e., between the two subassemblies 110.

[0056] 6 is a flowchart showing an example of a manufacturing procedure for the optical module 100. Here, the manufacturing procedure is exemplified when the optical fiber 301 is a polarization-maintaining optical fiber.

[0057] As shown in FIG. 6 , first, the subassemblies 110 are fabricated (S1). In S1, each of the above-described subassemblies 110 (see FIGS. 2 to 4 , but not yet attached to the base 101) is fabricated. At this time, the fixing position of the optical fiber 301 relative to the support member 117 and the fixing position of the lens 115 relative to the submount 111 are adjusted for each subassembly 110 so that the desired coupling efficiency of the light output from the laser light-emitting element 112 to the end 301e1 of the optical fiber 301 is obtained. Furthermore, if the optical fiber 301 is a polarization-maintaining optical fiber, the rotation angle of the optical fiber 301 about its optical axis (center axis) is also adjusted. Specifically, for example, the angle of the end 301e1 of the optical fiber 301 about its optical axis is adjusted so that the direction of tensile stress applied in the cross section substantially coincides with the slow axis direction of the laser light. S1 is an example of a first step.

[0058] Next, the position and angle around the central axis C of the end 301e2 of the optical fiber 301 fixed to the connector body 201 (see FIG. 1) are adjusted (S2). FIG. 7 is a front view showing the intended arrangement of the end 301e2 of the optical fiber 301 fixed to the connector body 201. As shown in FIG. 7, each optical fiber 301 has a core 301a, a cladding 301b, and two stress-applying members 301c. The core 301a extends along the central axis C (optical axis). The two stress-applying members 301c are arranged so that the midpoint between the two stress-applying members 301c approximately coincides with the central axis C. The cladding 301b is arranged to surround the core 301a and the two stress-applying members 301c. 7, the positions of the end portions 301e2 of the optical fibers 301 and the rotation angles around the central axes C are adjusted so that the central axes C, the cores 301a, and the stress-applying members 301c of the optical fibers 301 are aligned substantially along the arrangement direction V of the optical fibers 301, and the central axes C are aligned at predetermined intervals, for example, at equal intervals. S2 is an example of a fourth step.

[0059] 7, the ends 301e2 of the optical fibers 301 are fixed to the connector body 201 using a bonding material such as an adhesive (S3). S3 is an example of a third step.

[0060] Then, in S3, the ends 301e2 of the multiple optical fibers 301 are firmly fixed to the connector body 201, and then the multiple subassemblies 110 are attached to the base 101 (S4). In this manner, in this embodiment, by performing S4 via S3 after S1, if the lengths of the optical fibers 301 of the multiple subassemblies 110 are different from one another, the attachment positions of the multiple subassemblies 110 to the base 101 in the X direction will be uneven, as shown in Fig. 2. S4 is an example of a second step.

[0061] Furthermore, if S3 were to be performed after S4, after the adjustment to the state shown in Fig. 7 in S3, the torsional torque of the subassembly 110 or the optical fiber 301 would be transmitted to the end portion 301e2 before the bonding material solidifies, causing the end portion 301e2 to twist relative to the connector body 201, making it impossible to maintain the state shown in Fig. 7. In this regard, in the present embodiment, as described above, S4 is performed after S3, so that the end portion 301e2 can be fixed to the connector body 201 at the adjusted position and angle shown in Fig. 7. This makes it possible to prevent inconveniences such as rotation of the polarization plane of output light for an optical component (referred to as an external optical component) such as an optical fiber (not shown) connected to the connector module 200, or a decrease in the coupling efficiency of the output light to the external optical component.

[0062] After careful consideration, the inventors have found that various problems may arise if the plurality of laser light-emitting elements 112, optical components such as the lens 115 and the isolator 116, and the optical fiber 301 are all directly mounted on the common base 101. These problems include, for example, that in each combination of the laser light-emitting elements 112, the optical components, and the optical fiber 301, it takes time to adjust the positions of the laser light-emitting elements, the optical components, and the optical fiber 301 to increase the coupling efficiency, which increases the time required to manufacture one optical module 100, and that the size of the optical module 100 increases in order to avoid interference between the components and a jig used to adjust the positions.

[0063] In this regard, according to this embodiment, in S1, a subassembly 110 having a combination of a laser light-emitting element 112, optical components, and an optical fiber 301 is manufactured, and then in S4, the subassembly 110 is fixed to the base 101, thereby obtaining advantages such as reducing the effort and cost required to manufacture the optical module 100 and preventing the size of the optical module 100 from increasing.

[0064] Furthermore, with the above-described configuration and manufacturing method, in this embodiment, it is possible to relax restrictions on the length of the optical fibers 301 fixed to the subassemblies 110 for the multiple subassemblies 110. The lengths of the optical fibers 301 fixed to each subassembly 110 are likely to vary depending on factors such as variations in the cutting position in the process of cutting the ends and adjustments to the relative positions within the subassemblies 110 to improve coupling efficiency. Here, if the fixing positions of the ends 301e1 of the optical fibers 301 relative to the base 101 are restricted in an optical module 100 having multiple laser light-emitting elements 112 and optical fibers 301 corresponding to the laser light-emitting elements 112, the cutting process would require careful attention to align the lengths of the optical fibers 301, which could require time and effort, reduce the yield of the optical fibers 301, cause bending of the relatively long optical fibers 301 incorporated in the optical module 100, and generate stress due to the bending. In this regard, according to the present embodiment, a certain degree of misalignment (deviation) in the mounting positions of the multiple subassemblies 110 on the base 101 in the X direction is tolerated, and as a result, restrictions on the length of the optical fibers 301 fixed to each subassembly 110 can be relaxed, resulting in advantages such as reduced manufacturing effort and costs and avoidance of a decrease in the yield of the optical fibers 301.

[0065] Second Embodiment FIG. 8 is a perspective view showing a cross section of a subassembly 110B (110) of a second embodiment at a position equivalent to that shown in FIG. 4 . As shown in FIG. 8 , in this embodiment, the submount 111 has a first portion 111a and a second portion 111b. The first portion 111a is adjacent to the laser light-emitting element 112 and is bonded to the base 101. The first portion 111a and the base 101 are bonded together with a bonding material such as solder or adhesive. The second portion 111b extends from the first portion 111a in the X direction, away from the base 101, and supports optical components such as a lens 115 and an isolator 116, as well as an optical fiber 301. A gap 111c is provided between the second portion 111b and the base 101.

[0066] According to this embodiment, the bonding area between the submount 111 and the base 101 can be narrowed. Therefore, even if the difference in thermal expansion coefficient between the submount 111 and the base 101 is relatively large, the submount 111 can be prevented from warping or deforming due to temperature changes. Furthermore, because the first portion 111a is adjacent to the laser light-emitting element 112, which serves as a heat source, heat generated by the laser light-emitting element 112 can be transferred to the base 101 via the first portion 111a. In other words, even with this configuration, the required heat dissipation performance of the submount 111 can be ensured. It is sufficient that the second portion 111b supports at least the optical fiber 301, and the first portion 111a may support optical components.

[0067] Third Embodiment Figure 9 is a perspective view showing a cross section of a subassembly 110C (110) of a third embodiment, taken at the same position as in Figure 4. As shown in Figure 9, in this embodiment, the wiring 101a1 does not extend long in the X direction as in the first and second embodiments. Therefore, in this embodiment, to accommodate the misalignment of the subassemblies 110 (submounts 111) in the X direction as shown in Figures 2 and 3, the length of the wires 114b is increased as the submount 111 is farther away from the wiring 101a1 in the X direction, thereby ensuring electrical connection between the wiring 101a1 and the electrodes 113 of the submounts 111, i.e., the conductors of the subassemblies 110, in all subassemblies 110. In this case, the optical module 100 includes multiple wires 114b of different lengths; more specifically, multiple wires 114b that are longer as the distance in the X direction between the wiring 101a1 and the submount 111 increases. In this embodiment, the length of the second member 132 of the cover 130 in the X direction also increases as the distance in the X direction between the wiring 101a1 and the submount 111 and the length of the wire 114b increase.

[0068] While the above describes exemplary embodiments of the present invention, the above embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be appropriately modified and implemented.

[0069] For example, a first cover for each subassembly is not essential, and a first cover that covers a plurality of subassemblies may be provided.

[0070] The present invention can be used in an optical device and a method for manufacturing an optical device.

[0071] 10...Communication device 100...Optical module (optical device) 101...Base 101a...Surface 101a1...Wiring (wiring portion) 101a2...Insulating area 103...FPC 110, 110A, 110B, 110C...Subassembly 111...Submount 111a...First portion 111b...Second portion 111c...Gap 112...Laser light emitting element 113...Electrode (conductor) 114a...Wire 114b...Wire 115...Lens (optical component) 116...Isolator (optical component) 117...Support member 118...Adhesive 119...Adhesive 120...Photodiode 130...Cover 131...First member (first cover) 132...Second member (second cover) 133...Boot 140...Thermal conduction sheet 200...Connector module 201...Connector body 300... Optical fiber cable 301... Optical fiber 301a... Core 301b... Cladding 301c... Stress applying member 301e1... End 301e2... End 302... Tube 310... C... Central axis (optical axis) g... Gap S1... First step S2... Fourth step S3... Third step S4... Second step V... Arrangement direction X... Direction (first direction) Y... Direction (second direction) Z... Direction

Claims

1. An optical device comprising: a plurality of sub-assemblies each having a laser light emitting element, an optical fiber to which output light of the laser light emitting element is coupled, and a submount to which the laser light emitting element and the optical fiber are attached; and a base to which the plurality of sub-assemblies are attached.

2. The optical device according to claim 1, further comprising: a cable having a plurality of optical fibers extending from the plurality of sub-assemblies and a tube surrounding the plurality of optical fibers; and a connector to which ends of the plurality of optical fibers are fixed.

3. The optical device according to claim 1, wherein on the base, each optical fiber of the sub-assemblies extends substantially along a first direction and is arranged at intervals in a second direction intersecting the first direction.

4. The optical device according to claim 3, wherein positions of the plurality of sub-assemblies on the base in the first direction are uneven.

5. The optical device according to claim 3, comprising two adjacent sub-assemblies with a gap therebetween as two adjacent sub-assemblies in the second direction.

6. The optical device according to claim 1 or 5, further comprising a first cover covering at least the laser light emitting element and having light-shielding properties.

7. The optical device according to claim 6, wherein the first cover has a higher thermal conductivity than the gas around the laser light emitting element.

8. The optical device according to claim 7, wherein the first cover is thermally connected to the submount.

9. The optical device according to claim 1, further comprising a housing for accommodating the plurality of sub-assemblies.

10. The optical device according to claim 3 or 4, wherein the sub-assembly is fixed on a surface of the base, a wiring portion made of a conductor is provided on the surface, and the wiring portion and a conductor of the sub-assembly are electrically connected via a wire made of a conductor.

11. The optical device according to claim 10, wherein the wiring portion has a portion extending substantially along the first direction on the surface.

12. The optical device according to claim 10, comprising a plurality of wires having different lengths as the wire.

13. The optical device according to claim 10, comprising a second cover covering the wire.

14. The laser light emitting element outputs the output light in a first direction, and the submount has a first portion joined to the base adjacent to the laser light emitting element and a second portion extending from the first portion away from the base and supporting at least the optical fiber. The optical device according to claim 1.

15. The optical device according to claim 1 or 14, wherein the submount and the base have a higher thermal conductivity than the gas around the laser light emitting element.

16. The optical device according to claim 1 or 2, wherein the optical fiber is a polarization maintaining optical fiber.

17. A first step of creating a plurality of subassemblies each having a laser light emitting element, an optical fiber to which the output light of the laser light emitting element is coupled, and a submount to which the laser light emitting element and the optical fiber are attached; A second step of attaching the plurality of subassemblies to a base; A method of manufacturing an optical device.

18. The method of manufacturing an optical device according to claim 17, further comprising a third step of fixing ends of a plurality of optical fibers including the optical fibers extending from the plurality of subassemblies to a connector body after the first step and before the second step.

19. The plurality of optical fibers are polarization maintaining optical fibers, and the method of manufacturing an optical device according to claim 18 further comprises a fourth step of adjusting an angle of the ends around a central axis with respect to the connector body after the first step and before the third step.

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