Optical transmitter

Abstract

A light transmitter of one embodiment includes a plurality of light emitting elements, a plurality of light receiving elements that monitor output light from each of the plurality of light emitting elements, a housing that supports the plurality of light emitting elements and the plurality of light receiving elements, and a wiring substrate that is supported by the housing and includes a first region including pads that are electrically connected to the light emitting elements and a second region that is disposed at a position lower than the first region and includes pads that are electrically connected to the light receiving elements.

Description

Technical Field

[0001] This disclosure relates to an optical transmitter.

[0002] This application claims priority based on Japanese Application No. 2020-102401, filed on June 12, 2020, and invokes all the contents of the said Japanese application. Background Technology

[0003] Patent Document 1 describes a semiconductor light-emitting module. The semiconductor light-emitting module includes: a main part comprising a semiconductor light-emitting element; and a housing housing the main part of the semiconductor light-emitting module. The housing is a hermetically sealed enclosure, and the light element is mounted inside the enclosure.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-033037 Summary of the Invention

[0007] One type of light transmitter includes: a plurality of light-emitting elements; a plurality of light-receiving elements for monitoring output light from each of the plurality of light-emitting elements; a housing on which the plurality of light-emitting elements and the plurality of light-receiving elements are mounted; and a wiring substrate mounted on the housing, having a first region having a first pad electrically connected to the light-emitting elements and a second region disposed at a lower position than the first region and having a second pad electrically connected to the light-receiving elements. Attached Figure Description

[0008] Figure 1 This is a perspective view of the optical transmitter in an embodiment.

[0009] Figure 2 yes Figure 1 A longitudinal sectional view of the optical transmitter.

[0010] Figure 3 It means from Figure 1 A side view of the light transmitter with its cover removed.

[0011] Figure 4 It means from Figure 1 A stereoscopic view of the light transmitter with its cover removed.

[0012] Figure 5 It means Figure 1 A cross-sectional view of the housing, wiring board, light-emitting element, and spacer of the optical transmitter.

[0013] Figure 6 It means from Figure 1A top-down view of the light transmitter with its cover removed.

[0014] Figure 7 It means Figure 1 A cross-sectional view of the housing, synthesizer, light-receiving element, light-emitting element, wiring substrate, and spacers of the optical transmitter.

[0015] Figure 8 It is a schematic representation of the source Figure 7 A diagram showing the relationship between the output light of the light-emitting element and the position of the light-receiving element.

[0016] Figure 9 This is a top view showing the housing, synthesizer, wiring substrate, light-receiving element, and light-emitting element of the light transmitter in the first modified example.

[0017] Figure 10 It means Figure 9 A three-dimensional view of the housing, synthesizer, wiring board, light-receiving element, and light-emitting element.

[0018] Figure 11 This is a top view showing the housing, synthesizer, wiring substrate, light-receiving element, and light-emitting element of the light transmitter in the first modified example.

[0019] Figure 12 This is a cross-sectional view showing the housing, synthesizer, wiring substrate, light-receiving element, and light-emitting element of the light transmitter in the second modified example.

[0020] Figure 13 This is a top view showing the housing, synthesizer, wiring substrate, light-receiving element, and light-emitting element of the light transmitter in the second modified example.

[0021] Figure 14 This is an enlarged top view of the wiring substrate, light-receiving element, and light-emitting element of a further modification of the second modification. Detailed Implementation

[0022] Furthermore, unlike the aforementioned sealed housings, light transmitters with non-sealed (non-hermetic) housings are sometimes used to reduce costs. The light transmitter includes: an LD (Laser Diode); a carrier housing the LD; an FPC (Flexible Printed Circuit) with pads electrically connected to the LD; and a monitoring PD (Photo Diode) to monitor the light from the LD.

[0023] The LD is electrically connected to the wiring pattern of the FPC, and the monitoring PD is electrically connected to the wiring pattern on the carrier. It is known that optical transmitters, such as LDs, are mounted on a metal base without using the aforementioned carrier. In the case of this optical transmitter, it is impossible to set a wiring pattern on the metal base. Therefore, it is conceivable to arrange a carrier with a wiring pattern on the base. However, further configuring the carrier on the base may lead to an increase in cost.

[0024] The purpose of this disclosure is to provide an optical transmitter that does not require a carrier with a wiring pattern.

[0025] According to this disclosure, it is not necessary to configure a carrier with wiring patterns.

[0026] The following description outlines embodiments of the present disclosure. One embodiment of the light transmitter includes: a plurality of light-emitting elements; a plurality of light-receiving elements for monitoring output light from each of the plurality of light-emitting elements; a housing on which the plurality of light-emitting elements and the plurality of light-receiving elements are mounted; and a wiring substrate mounted on the housing, having a first region having a first pad electrically connected to the light-emitting elements and a second region disposed at a lower position than the first region and having a second pad electrically connected to the light-receiving elements.

[0027] In this light transmitter, a wiring substrate is mounted on a housing that houses multiple light-emitting elements and multiple light-receiving elements. The wiring substrate has: a first region having a first pad electrically connected to each of the multiple light-emitting elements; and a second region having a second pad electrically connected to each of the multiple light-receiving elements. Since both the second pads electrically connected to the light-receiving elements and the first pads electrically connected to the light-emitting elements are located on the wiring substrate, electrical wiring can be provided on the housing. Even if the housing is made of metal, electrical wiring can be provided on the wiring substrate extending from the housing, thus eliminating the need for a carrier with wiring patterns. As a result, cost increases can be suppressed. The second pads electrically connected to the light-receiving elements are positioned lower than the first pads electrically connected to the light-emitting elements. Therefore, wiring extending from the light-receiving elements to the second pads is less likely to overlap with the output light, thus preventing the wiring from obstructing the optical path of the output light. As a result, the output light can be monitored more reliably at the light-receiving elements.

[0028] Alternatively, multiple light-emitting elements and multiple light-receiving elements may be arranged along the first direction. Alternatively, the wiring substrate may have a connection region connecting the first region and the second region to each other. Alternatively, the width of the connection region in the first direction may be narrower than the width of the first region in the first direction and the width of the second region in the first direction. In this case, by narrowing the width of the connection region connecting the first region and the second region to each other, an increase in the area of ​​the wiring substrate can be suppressed. Therefore, a compact configuration of the components can be achieved.

[0029] Alternatively, the connecting region may extend from the end of the first region in the first direction to the end of the second region in the first direction. In this case, the width of the connecting region in the first direction can be further narrowed.

[0030] Alternatively, the thickness of the wiring substrate in the first region can be the same as the thickness of the wiring substrate in the second region, and the connection area can have a height difference or a sloped portion. In this case, by making the thickness of the wiring substrate in the first region the same as the thickness of the wiring substrate in the second region, the structure of the wiring substrate can be simplified.

[0031] Alternatively, the aforementioned optical transmitter may also include a spacer disposed between the first region of the wiring substrate and the housing. In this case, the spacer is sandwiched between the first region of the wiring substrate, which is higher than the second region, and the housing. Therefore, the first region can be held in a more stable state by means of the spacer.

[0032] Alternatively, the aforementioned light transmitter may also include a cover that covers the housing, and the housing has guide pins that define the position of the cover relative to the housing. Alternatively, the wiring substrate may have an extended region extending along the extension line of the connection region and from the second region along a second direction intersecting the first direction, with holes formed in the extended region for insertion of the guide pins. In this case, the extended region of the wiring substrate extending from the connection region can be effectively utilized as the region for forming the holes for insertion of the guide pins of the housing.

[0033] Alternatively, the second pad in the second region of the wiring substrate can be positioned offset from the optical axis of the output light from the light-emitting element. In this case, the possibility of wiring extending from the second pad interfering with the output light can be further reduced.

[0034] Alternatively, the second pad can be located on the outer side of the optical axis in the first direction in the second region of the wiring substrate. In this case, by positioning the second pad on the outer side in the first direction, interference of the wiring extending from the second pad to the light-receiving element on the output light can be suppressed more reliably.

[0035] Alternatively, the aforementioned light transmitter may further include: a combiner for combining the output light from each of a plurality of light-emitting elements; and a socket disposed on the light output side of the housing when viewed from the combiner. Alternatively, the optical axis of the light passing through the socket may be the same as the optical axis of the light combined by the combiner, and located at an end side closer to the center of the housing in the first direction. Alternatively, the connection area may be located at an end side closer to the center of the housing in the first direction and on the same side as the socket. In this case, the connection area can be positioned on the same side as the socket in the first direction.

[0036] Alternatively, the light-receiving element can be a surface-incident type, with the mounting surface of the carrier on which it is mounted tilted, and the light-receiving surface of the light-receiving element configured at an angle relative to the optical axis of the output light. Alternatively, the second region can be located on the opposite side of the light-emitting element when viewed from the carrier. In this case, by configuring the light-receiving surface at an angle relative to the optical axis, a portion of the output light can be monitored with higher precision at the surface-incident type light-receiving element.

[0037] Hereinafter, specific examples of the optical transmitter of this disclosure will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to the examples described below, but is shown in the claims and is intended to include all modifications within the scope equivalent to the claims. In the description of the drawings, the same or equivalent elements are labeled with the same reference numerals, and repeated descriptions are omitted where appropriate. For ease of understanding, parts of the drawings may sometimes be simplified or exaggerated, and the dimensions, proportions, etc., are not limited to what is depicted in the drawings.

[0038] Figure 1 This is a perspective view showing the optical transmitter 1 of this embodiment. Figure 1 As shown, the optical transmitter 1 includes a housing 2, a cover 3 covering the housing 2, a receptacle 4 having a cylindrical sleeve, and a wiring board 5. The optical transmitter 1 extends along the longitudinal direction D1, and the receptacle 4, the cover 3 (housing 2), and the wiring board 5 are arranged in this order.

[0039] Figure 2 This is a partial cross-sectional view of optical transmitter 1. (See attached image.) Figure 1 and Figure 2 As shown, the housing 2 includes: a lower plate 2A extending along the longitudinal direction D1; and a side wall 2B extending from one end of the lower plate 2A in the longitudinal direction D1 along the height direction D2. The housing 2 is, for example, made of metal. As an example, the material of the housing 2 is Kovar (an alloy in which nickel and cobalt are combined with iron) or SUS (Stainless Steel). The housing 2 may also be made of iron, chromium, an alloy of iron and chromium, an alloy of iron and nickel, or plastic.

[0040] The shape of the housing 2, as viewed from the width direction D3 of the light transmitter 1, is L-shaped. The housing 2 is also referred to as an L-shaped base. A socket 4 is formed on the side wall 2B for insertion and serves as the output light L (see reference). Figure 3 The socket 4 has an outlet hole that penetrates the sidewall 2B in the longitudinal direction D1. The socket 4 is formed in a cylindrical shape. The socket 4 has a plurality of flanges 4c, one of which functions as a guide 4b that determines the position of the socket 4. With regard to the socket 4, in the state of being fixed to the housing 2, for example, the guide 4b contacts the outer surface 2f of the sidewall 2B.

[0041] When viewed from the height direction D2, for example, the housing 2 is rectangular. The housing 2 is a component that houses the parts inside the light transmitter 1, and each part of the light transmitter 1 is mounted on the lower plate 2A. The lower plate 2A is a long strip that protrudes from the side wall 2B along the longitudinal direction D1, and each part of the light transmitter 1 is mounted on this long strip. The lower plate 2A includes: a main surface 2b, which faces the parts inside the light transmitter 1; a convex mounting surface 2c, which mounts the parts; a guide pin 2d, which determines the position of the cover 3 relative to the housing 2; and an outer surface 2f, which protrudes from the outside of the light transmitter 1.

[0042] The main surface 2b is a rectangle extending in both the longitudinal direction D1 and the width direction D3. The mounting surface 2c is a portion of the main surface 2b that protrudes along the height direction D2. For example, components such as the synthesizer 6 that performs optical wave combining are mounted on the mounting surface 2c. A guide pin 2d protrudes from the main surface 2b along the height direction D2. The guide pin 2d is, for example, cylindrical. The guide pin 2d is, for example, located on one side in the width direction D3 (at a position offset from the center of the housing 2 in the width direction D3).

[0043] Cover 3 is a component that covers housing 2 from the height direction D2, and the components of light transmitter 1 are housed inside housing 2 and cover 3. Cover 3 has: an outer surface 3b, which protrudes from the outside of light transmitter 1; and an inner surface 3c, which faces the components of light transmitter 1. The inner surface 3c has: a protrusion 3d, which protrudes toward guide pin 2d of housing 2; and a hole 3f, which is formed inside the protrusion 3d for guide pin 2d to be inserted in the height direction D2. Cover 3 is fixed to housing 2 by guide pin 2d being inserted into hole 3f.

[0044] Figure 3 This is a side view of the housing 2, showing the state where the cover 3 has been removed from the light transmitter 1. (See image.) Figure 2 and Figure 3As shown, the light transmitter 1 includes a wiring substrate 5, a combiner 6, a light-receiving element 7, a first lens 8, a light-emitting element 9, and a spacer 10 inside the housing 2 and cover 3. A portion of the wiring substrate 5 extends from the housing 2 and cover 3 toward the opposite side of the socket 4. The portion of the wiring substrate 5 extending toward the opposite side of the socket 4 protrudes to the outside of the light transmitter 1.

[0045] Figure 4 This is a perspective view showing the socket 4, the housing 2, and the light transmitter 1 mounted on the main surface 2b of the housing 2. (See diagram below.) Figure 3 and Figure 4 As shown, the light transmitter 1 also includes a second lens 11 sandwiched between the socket 4 and the combiner 6. For example, the light transmitter 1 includes four light-emitting elements 9, four first lenses 8, four light-receiving elements 7, the combiner 6, and the second lens 11.

[0046] The light transmitter 1 is a four-lane multi-channel light-emitting module comprising four light-receiving elements 7, four first lenses 8, and four light-emitting elements 9. In this light transmitter 1 with four output light paths L, the optical path length of the output light L is different in each channel. The socket 4 is, for example, positioned offset from the center of the housing 2 in the width direction D3. The end located on the opposite side of the socket 4 in the width direction D3 (in...) Figure 4 The light path of the output light L from the light-emitting element 9 (located at the upper end) is the longest. The light from the end of the socket 4 located on the width direction D3 (in...) Figure 4 The light path of the output light L of the light-emitting element 9 (located at the lower end) is the shortest.

[0047] The housing 2 is equipped with a plurality of light-emitting elements 9 and a plurality of light-receiving elements 7. The plurality of light-emitting elements 9 are arranged along the width direction D3 (first direction), and the plurality of light-receiving elements 7 are arranged along the width direction D3. For example, each of the four light-emitting elements 9 is mounted on the main surface 2b of the housing 2 via a carrier 12 (first mounting part). Each light-emitting element 9 is provided corresponding to each of the four first lenses 8 and each of the four light-receiving elements 7. Each light-emitting element 9 is, for example, a semiconductor laser diode (LD). The output light L, which is divergent light, emitted from the light-emitting element 9 is converted into collimated light by each of the first lenses 8.

[0048] The output light L emitted from the light-emitting element 9 via the first lens 8 is input to the combiner 6 in such a way that a portion of it passes through the light-receiving element 7. The combiner 6 is, for example, an optical combiner that combines four output lights L. The four output lights L are combined inside the combiner 6 and output as a single output light L from the combiner 6 to the second lens 11. The second lens 11 converges the output light L from the combiner 6 to an optical fiber held in the socket 4, and the output light L is output to the outside of the optical transmitter 1 via this optical fiber held in the socket 4.

[0049] The light-receiving element 7 is a monitoring PD (PhotoDiode) that monitors the output light L from each of the plurality of light-emitting elements 9. The light-receiving element 7 monitors the intensity of the output light L by receiving a portion of the output light L from the light-emitting elements 9. For example, each of the four light-receiving elements 7 is mounted on the main surface 2b of the housing 2 via a carrier 13 (second mounting portion) formed of a material containing a dielectric or a protrusion provided on the housing 2.

[0050] The light-receiving element 7 converts a portion of the output light L from the light-emitting element 9 into an electrical signal, and outputs the converted electrical signal via a wire (not shown) to the pad 5b (second pad) of the wiring substrate 5. The light-receiving element 7 and the wire extending from the light-receiving element 7 are located closer to the light output side (socket 4 side) than the light-emitting element 9. By outputting an electrical signal from the light-receiving element 7, APC (Auto Power Control) can be performed on the output light L from the light-emitting element 9.

[0051] The wiring substrate 5 is, for example, an FPC (Flexible Printed Circuit) mounted on the housing 2. The housing 2 has a pair of upwardly projecting protrusions 2g at its end opposite the sidewall 2B in the longitudinal direction D1. The pair of protrusions 2g are arranged in the width direction D3. The wiring substrate 5 includes: a first region 5A extending outward from the light transmitter 1; a second region 5B having pads 5b; and a connection region 5C connecting the first region 5A and the second region 5B to each other. When viewed from the height direction D2, the first region 5A, the second region 5B, and the connection region 5C are arranged in a C-shape.

[0052] Each of the two ends of the first region 5A in the width direction D3 has a recess 5c. The first region 5A has a pair of recesses 5c arranged in the width direction D3, and the wiring substrate 5 is fixed to the housing 2 by the protrusions 2g of the housing 2 being inserted into the recesses 5c. The first region 5A has a pad 5d (first pad) for electrical connection with the light-emitting element 9. For example, each of the plurality of light-emitting elements 9 is electrically connected to the pad 5d via a wire 14. The first region 5A is located at a position higher than the second region 5B (a position further away from the main surface 2b of the housing 2 than the second region 5B), for example, the height of the first region 5A is the same as the height of the carrier 12 on which the light-emitting element 9 is mounted. As a result, the length of the wire 14 extending from each light-emitting element 9 can be shortened.

[0053] For example, a wiring substrate 5 has a first region 5A as the upper layer and a second region 5B as the lower layer, which are fixed to the housing 2 by adhesive bonding. The second region 5B is located at a lower position than the first region 5A, for example, in contact with the main surface 2b of the housing 2. By positioning the second region 5B so low, the wires extending from the wiring substrate 5 or the light-receiving element 7 do not interfere with the output light L passing through the light-emitting element 9 and the first lens 8.

[0054] Figure 5 This is an enlarged longitudinal sectional view of the housing 2, showing the spacer 10. (See image.) Figure 5 As shown, the spacer 10 is disposed between the first region 5A and the housing 2. For example, the spacer 10 ensures the height of the first region 5A. It should be noted that a reinforcing plate made of insulating material can also be provided in the first region 5A of the wiring substrate 5 instead of the spacer 10. In this case, a wiring pattern can also be provided on the lower surface of the first region 5A.

[0055] Figure 6 This is a top view showing the housing 2, socket 4, wiring board 5, synthesizer 6, light receiving element 7, first lens 8, light emitting element 9, and second lens 11. Figure 7 This is a longitudinal sectional view showing the housing 2, wiring substrate 5, synthesizer 6, light-receiving element 7, first lens 8, and light-emitting element 9. (Example) Figure 6 and Figure 7 As shown, the width (length in the width direction D3) of the connection area 5C of the wiring substrate 5 is narrower than the width of the first area 5A and the width of the second area 5B.

[0056] Connection area 5C, for example, is located on the side of socket 4 in the width direction D3 (in Figure 6The connection region 5C extends from the end of the first region 5A in the width direction D3 to the end of the second region 5B in the width direction D3. This allows the socket 4 to be positioned inside the end in the width direction D3, rather than at the end in the width direction D3. The thickness of the wiring substrate 5 in the first region 5A and the thickness of the wiring substrate 5 in the second region 5B are, for example, the same. The connection region 5C extends in the longitudinal direction D1 between the first region 5A and the second region 5B, for example, located at the end of the housing 2 in the width direction D3. The connection region 5C has a height difference or inclined portion located between the first region 5A and the second region 5B. In this embodiment, an example is shown where the connection region 5C has an inclined portion 5f.

[0057] Figure 8 This is a schematic side view showing the light-receiving element 7, the first lens 8, and the carrier 13. (Example) Figure 7 and Figure 8 As shown, the second region 5B is a PD wiring FPC with pads 5b for wiring to the light-receiving element 7, located on the light output side (socket 4 side) of the light-receiving element 7. The aforementioned carrier 13 has a mounting surface 13b for mounting the light-receiving element 7. The mounting surface 13b is arranged obliquely relative to the optical axis of the output light L from the light-emitting element 9 (the optical axis extending along the longitudinal direction D1 from the light-emitting element 9).

[0058] The light-receiving element 7 is a surface-incident type light-receiving element, having a light-receiving surface 7b on its surface. Because the mounting surface 13b is arranged at an angle relative to the optical axis of the output light L, the light-receiving surface 7b of the light-receiving element 7 is also arranged at an angle relative to the optical axis of the output light L. By configuring the light-receiving element 7 such that its light-receiving surface 7b forms an angle θ relative to the optical axis of the output light L, the light-receiving element 7 receives a portion of the output light L.

[0059] By arranging the light-receiving element 7 on the light output side of the light-emitting element 9, the output light L can be monitored with a simple configuration on the light output side. The wiring, such as wires, used for monitoring the PD, of the light-receiving element 7 is located closer to the light output side than the light-receiving element 7. Therefore, an electrical connection with the light-receiving element 7 can be achieved without reducing its light-receiving sensitivity. The light-receiving element 7 is, for example, directly wired to the pad 5b on the wiring board 5, thus eliminating the need for a separate mounting carrier. This contributes to cost reduction.

[0060] The effects obtained from the light transmitter 1 of this embodiment will be described in detail. In the light transmitter 1, a wiring board 5 is mounted on a housing 2 that houses a plurality of light-emitting elements 9 and a plurality of light-receiving elements 7. The wiring board 5 has: a first region 5A having pads 5d electrically connected to each of the plurality of light-emitting elements 9; and a second region 5B having pads 5b electrically connected to each of the plurality of light-receiving elements 7. Thus, the pads 5b electrically connected to the light-receiving elements 7 and the pads 5d electrically connected to the light-emitting elements 9 are both provided on a single wiring board 5, thereby allowing electrical wiring to be provided on the housing 2.

[0061] Even if the housing 2 is made of metal, electrical wiring can be provided on the wiring substrate 5 extending from the housing 2, thus eliminating the need for a carrier or similar device with wiring patterns. As a result, cost increases can be suppressed. The pad 5b, which is electrically connected to the light-receiving element 7, is positioned lower than the pad 5d, which is electrically connected to the light-emitting element 9. Therefore, wiring such as wires extending from the light-receiving element 7 to the pad 5b is less likely to overlap with the output light L, thus preventing the wiring from obstructing the optical path of the output light L. As a result, the output light L can be monitored more reliably at the light-receiving element 7.

[0062] Alternatively, multiple light-emitting elements 9 can be arranged along the width direction D3, and multiple light-receiving elements 7 can be arranged along the width direction D3. Alternatively, the wiring substrate 5 can have a connection region 5C that connects the first region 5A and the second region 5B to each other. Alternatively, the width (length in the width direction D3) of the connection region 5C can be narrower than the width of each of the first region 5A and the second region 5B. In this case, by narrowing the width of the connection region 5C that connects the first region 5A and the second region 5B to each other, the increase in the area of ​​the wiring substrate 5 can be suppressed. Therefore, a compact configuration of the components can be achieved.

[0063] Alternatively, the connecting region 5C can extend from the end of the first region 5A in the width direction D3 to the end of the second region 5B in the width direction D3. In this case, the width of the connecting region 5C in the width direction D3 can be further narrowed.

[0064] Alternatively, the thickness of the wiring substrate 5 in the first region 5A and the thickness of the wiring substrate 5 in the second region 5B may be the same. Alternatively, the connection region 5C may have a height difference or an inclined portion 5f. In this case, by making the thickness of the wiring substrate 5 in the first region 5A and the thickness of the wiring substrate 5 in the second region 5B the same, the configuration of the wiring substrate 5 can be simplified.

[0065] Alternatively, the optical transmitter 1 may also include a spacer 10 disposed between the first region 5A of the wiring substrate 5 and the housing 2. In this case, the spacer 10 is sandwiched between the first region 5A of the wiring substrate 5, which is higher than the second region 5B, and the housing 2. Therefore, the first region 5A can be held in a more stable state by means of the spacer 10.

[0066] Alternatively, the light transmitter 1 may also include: a combiner 6 for combining the output light L from each of the plurality of light-emitting elements 9; and a socket 4, which is disposed on the light output side of the housing 2 when viewed from the combiner 6. Alternatively, the optical axis of the light passing through the socket 4 may be the same as the optical axis of the light combined by the combiner 6, and located at an end closer to the center of the housing 2 in the width direction D3. Alternatively, the connection region 5C may be located at an end closer to the center of the housing 2 in the width direction D3 and on the same side as the socket 4. In this case, the position of the connection region 5C in the width direction D3 can be configured to be biased towards the same side as the socket 4.

[0067] Alternatively, the light-receiving element 7 can be a surface-incident type light-receiving element, and the mounting surface 13b of the carrier 13 on which the light-receiving element 7 is mounted is inclined. Alternatively, the light-receiving surface 7b of the light-receiving element 7 can be arranged at an angle relative to the optical axis of the output light L, and the second region 5B is positioned on the opposite side of the light-emitting element 9 when viewed from the carrier 13. In this case, by arranging the light-receiving surface 7b at an angle relative to the optical axis of the output light L, a portion of the output light L can be monitored with higher precision at the surface-incident type light-receiving element 7.

[0068] The housing 2 can be manufactured using MIM (Metal Powder Injection Molding). In this case, the manufacturing cost of the housing 2 can be reduced. In the housing 2, the side wall 2B of the mounting socket 4 and the lower plate 2A of the mounting component are integrated, thus forming a housing 2 that is less prone to component tolerances and has high rigidity. The end of the housing 2 opposite to the side wall 2B in the longitudinal direction D1 has a pair of upwardly projecting protrusions 2g. Therefore, even if the housing 2 with the mounted component is mistakenly arranged upside down, for example, the side wall 2B and the protrusions 2g will touch the base plate, thus preventing the mounted component from interfering with the base plate, etc.

[0069] Reference Figure 9 , Figure 10 as well as Figure 11 The optical transmitter 21 of the first modified example will be described. Figure 9 This is a top view of the wiring substrate 25 of the light transmitter 21 in the first modified example. Figure 10This is a perspective view showing the housing 2, socket 4, wiring board 25, synthesizer 6, light receiving element 7, light emitting element 9, and spacer 10 of the light transmitter 21. Figure 11 This is a top view showing the housing 2, socket 4, wiring board 25, combiner 6, light-receiving element 7, and light-emitting element 9 of the light transmitter 21. A portion of the structure of the light transmitter 21 is the same as a portion of the structure of the aforementioned light transmitter 1; therefore, descriptions of the structure of the light transmitter 21 that are redundant with those of the light transmitter 1 are appropriately omitted. The same reference numerals are used to describe the same constituent elements of the light transmitter 21 as those of the light transmitter 1.

[0070] In addition to the aforementioned first region 5A, second region 5B, and connection region 5C, the wiring substrate 25 also has an extension region 25A that extends further along the longitudinal direction D1 from the connection region 5C. The extension region 25A protrudes, for example, from the second region 5B toward the opposite side of the connection region 5C. A hole 25c is formed in the extension region 25A for inserting the guide pin 2d of the housing 2, and the hole 25c extends through in the height direction D2.

[0071] The wiring substrate 25, like the aforementioned wiring substrate 5, includes a first region 5A and a second region 5B. The second region 5B has pads 25b (second pads) for connecting wires 7d from the light-receiving element 7. For each light-receiving element 7, for example, two wires 7d and two pads 25b are provided. The two wires 7d and two pads 25b are positioned away from the optical axis of the output light L. For example, when viewed from the height direction D2, the wires 7d and pads 25b are positioned so as not to overlap with the optical axis of the output light L.

[0072] The first modified light transmitter 21, like the light transmitter 1, includes a cover 3 covering the housing 2, and the housing 2 has a guide pin 2d that defines the position of the cover 3 relative to the housing 2. The wiring substrate 25 has an extension region 25A extending along the extension line of the connection region 5C and from the second region 5B along the longitudinal dimension direction D1 (second direction) intersecting the width direction D3. A hole 25c for inserting the guide pin 2d is formed in the extension region 25A. Thus, the extension region 25A of the wiring substrate 25 extending from the connection region 5C can be effectively utilized as the region for forming the hole 25c for inserting the guide pin 2d of the housing 2.

[0073] The pad 25b of the second region 5B of the wiring substrate 25 is located at a position offset from the optical axis of the output light L from the light-emitting element 9. Therefore, the possibility of the wire 7d extending from the pad 25b interfering with the output light L can be further reduced.

[0074] Reference Figure 12 , Figure 13 as well as Figure 14 The optical transmitter 31 of the second modified example will be described. Figure 12 This is a longitudinal sectional view of the housing 2 of the light transmitter 31, including the socket 4, wiring board 35, synthesizer 6, light receiving element 7, and light emitting element 9. Figure 13 This is a top view showing the wiring substrate 35, the light-receiving element 7, the first lens 8, and the light-emitting element 9. Figure 14 It means Figure 13 A top view of yet another modification of the second modification of the wiring substrate 35.

[0075] like Figure 13 and Figure 14 As shown, in the second modified example of the light transmitter 31, the wiring substrate 35, which has a different shape than the aforementioned wiring substrate 25, and the morphology of the wires 37d extending from the light-receiving element 7 are different from the previous example. The wiring substrate 35, like the aforementioned wiring substrate 25, includes a first region 5A, a second region 5B, and a connection region 35C. Alternatively, the wiring substrate 35 may also include an extension region 35D. When viewed from the height direction D2, the first region 5A, the second region 5B, and the connection region 35C are arranged in a U-shape.

[0076] However, the orientation of the U-shape formed by the first region 5A, the second region 5B, and the connecting region 35C is opposite to the orientation of the aforementioned U-shape formed by the first region 5A, the second region 5B, and the connecting region 5C. That is, the positions of the connecting region 35C and the extension region 35D in the width direction D3 are different from the positions of the connecting region 5C and the extension region 25A in the width direction D3. Correspondingly, in the light transmitter 31, the deviation of the socket 4 from the center in the width direction D3 is opposite to the aforementioned deviation of the socket 4. That is, the socket 4 of the light transmitter 31 is offset from the center in the width direction D3 to the same side as the connecting region 35C and the extension region 35D (in... Figure 13 and Figure 14 (The middle is the upper side).

[0077] like Figure 14 As shown, a pad 35b (second pad) for connecting wires 37d from the light-receiving element 7 is provided in the second region 5B of the wiring substrate 35. The two wires 37d and the two pads 35b are positioned to avoid the optical axis of the output light L. That is, similar to the aforementioned light transmitter 21, when viewed from the height direction D2, the wires 37d and pads 35b are positioned so as not to overlap with the optical axis of the output light L. The wires 37d extending from the light-receiving element 7 extend obliquely from the center in the width direction D3 towards the outer side in the width direction D3 of the housing 2.

[0078] In the second modification and yet another modification of the second modification, in the light transmitter 31, the pad 35b is located on the outer side of the width direction D3 of the optical axis of the output light L in the second region 5B of the wiring substrate 35. Therefore, by positioning the pad 35b on the outer side in the width direction D3, interference from the wire 37d extending from the pad 35b to the light-receiving element 7 to the output light L can be suppressed more reliably.

[0079] The embodiments of the optical transmitter of this disclosure have been described above. However, the present invention is not limited to the foregoing embodiments. That is, those skilled in the art will readily recognize that various modifications and alterations can be made to the present invention without changing the spirit of the claims. For example, the shape, size, quantity, material, and configuration of the components of the optical transmitter are not limited to the foregoing and can be appropriately modified. For example, in the foregoing, optical transmitter 1, optical transmitter 21, and optical transmitter 31 have been described as embodiments of the optical transmitter. However, it is also possible for a portion of these optical transmitters 1, 21, and 31 to constitute an optical transmitter that is combined with each other.

[0080] Explanation of reference numerals in the attached figures

[0081] 1, 21, 31: Optical transmitter

[0082] 2: Shell

[0083] 2A: Lower plate

[0084] 2B: Sidewall

[0085] 2b: Main face

[0086] 2c: Mounting surface

[0087] 2d: Guide pin

[0088] 2f: Outer surface

[0089] 2g: Protrusion

[0090] 3: Cover

[0091] 3b: Outer surface

[0092] 3c: Inner surface

[0093] 3d: convex part

[0094] 3f: Hole

[0095] 4: Socket

[0096] 4b: Guide

[0097] 4c: Flange

[0098] 5, 25, 35: Wiring substrate

[0099] 5A: Zone 1

[0100] 5b, 25b, 35b: Pads (second pads)

[0101] 5B: Second Zone

[0102] 5C, 35C: Connecting areas

[0103] 5c: concave part

[0104] 5d: Pad (first pad)

[0105] 5f: Inclined section

[0106] 6: Synthesizer

[0107] 7: Light receiving element

[0108] 7b: Light-receiving surface

[0109] 7d, 37d: Wire

[0110] 8: First lens

[0111] 9: Light-emitting element

[0112] 10: Spacer

[0113] 11: Second lens

[0114] 12, 13: Carrier

[0115] 13b: Mounting surface

[0116] 14: Electrical wires

[0117] 25A, 35D: Extended areas

[0118] 25c: Hole

[0119] D1: Long dimension direction (second direction)

[0120] D2: Height direction

[0121] D3: Width direction (first direction)

[0122] L: Output light.

Claims

1. An optical transmitter, comprising: Multiple light-emitting elements; Multiple light-receiving elements monitor the output light from each of the multiple light-emitting elements; A housing, housing the plurality of light-emitting elements and the plurality of light-receiving elements; and A wiring substrate, mounted on the housing, includes a first region having a first pad electrically connected to the light-emitting element, a second region having a second pad electrically connected to the light-receiving element, and a connection region connecting the first region and the second region. The plurality of light-emitting elements and the plurality of light-receiving elements are configured to be arranged along a first direction intersecting the optical axis. The first region and the second region are separated by the plurality of light-emitting elements and the plurality of light-receiving elements. The wiring substrate has a U-shape formed by the first region, the second region, and the connection region. The bottom surface of the 'ko' shape is formed by the connecting area, and the plurality of light-emitting elements and the plurality of light-receiving elements are arranged in the area inside the 'ko' shape.

2. The optical transmitter according to claim 1, further comprising: A beam combiner, mounted on the housing, receives output light from multiple input terminals located on one side from the output light of the multiple light-emitting elements, combines the input output light, and outputs the combined beam to an output terminal located on the opposite side and offset from the center of the opposite side; and An optical inlet, located in the housing, is used to guide the combined light output from the output end of the optical combiner, and is positioned near the center of the width of the housing.

3. The optical transmitter according to claim 2, wherein, The width of the connecting region in the first direction is narrower than the width of the first region in the first direction and the width of the second region in the first direction. The plurality of light-emitting elements and the plurality of light-receiving elements are biased at positions corresponding to the plurality of input terminals of the optical combiner, thereby the connection area of ​​the wiring substrate is disposed on the surface of the housing in an area where the light-emitting elements and the light-receiving elements are not disposed.

4. The optical transmitter according to any one of claims 1 to 3, wherein, The second region is positioned lower than the first region. The thickness of the wiring substrate in the first region is the same as the thickness of the wiring substrate in the second region, and the connection region has a height difference or an inclined portion.

5. The optical transmitter according to claim 2, wherein, The light inlet is located on the side of the wiring substrate where the connection area is located, at the center of the width of the housing.

6. The optical transmitter according to any one of claims 1 to 5, It also includes a cover that covers the housing. The housing has guide pins that determine the position of the cover relative to the housing. The wiring substrate has an extension region on the extension line of the connection region and extends from the second region along a second direction intersecting the first direction. A hole is formed in the extended region for the insertion of the guide pin.

7. The optical transmitter according to any one of claims 1 to 6, wherein, The second pad of the second region of the wiring substrate is located at a position offset from the optical axis of the output light from the light-emitting element.

8. The optical transmitter according to claim 7, wherein, The second pad is located on the outside of the first direction of the optical axis in the second region of the wiring substrate.

9. The optical transmitter according to any one of claims 1 to 8, wherein, The light-receiving element is a surface-incident type light-receiving element. The mounting surface of the carrier on which the light-receiving element is mounted is inclined, and the light-receiving surface of the light-receiving element is arranged at an angle relative to the optical axis of the output light. The second region is located on the opposite side of the light-emitting element when viewed from the carrier.

10. An optical device comprising: Multiple first optical elements; Multiple second optical elements are optically coupled to the multiple first optical elements; A housing, housing the plurality of first optical elements and the plurality of second optical elements; and A wiring substrate, mounted on the housing, includes a first region having a first pad electrically connected to the first optical element, a second region having a second pad electrically connected to the second optical element, and a connection region connecting the first region and the second region. The plurality of first optical elements and the plurality of second optical elements are configured to be arranged along a first direction intersecting the optical axis. The wiring substrate has a U-shape formed by the first region, the second region, and the connection region. The bottom surface of the 'ko' shape is formed by the connecting area, and the 'ko' shape is defined as the area that sandwiches the plurality of first optical elements and the plurality of second optical elements inside the 'ko' shape.

11. The optical device according to claim 10, further comprising: A socket, disposed in the housing, positioned near the center of the width of the housing; and An optical component, mounted on the housing, has: a plurality of first ends disposed on one side and optically coupled to the plurality of first optical elements; and a second end disposed on the other side opposite the first side, positioned at a center offset relative to the other side, and optically coupled to the socket.

12. The optical device according to claim 11, wherein, The width of the connecting region in the first direction is narrower than the width of the first region in the first direction and the width of the second region in the first direction. The plurality of first optical elements and the plurality of second optical elements are biased at positions corresponding to the plurality of first ends of the optical component, thereby the connection area of ​​the wiring substrate is disposed on the surface of the housing in an area where the first optical elements and the second optical elements are not disposed.

Images