Optical transceiver module

Abstract

To provide an optical transceiver module that can suppress an increase in the number of components. [Solution] The optical transceiver module 1 comprises a lens unit 2 having a transmitting optical fiber 4a and a receiving optical fiber 4b and a lens member 5, a light-emitting element 6 that emits an optical signal to the transmitting optical fiber 4a, a light-receiving element 7 that receives an optical signal from the receiving optical fiber 4b, and a substrate 3 to which the light-emitting element 6 and the light-receiving element 7 are attached. A recess 33 is formed in the substrate 3, and a positioning hole 33a is formed in the bottom wall portion 34 of the recess 33. A convex portion 54 is formed in the lens member 5 that is housed in the recess 33, and a positioning pin 55a is formed in the bottom surface portion 54a of the convex portion 54 that is inserted into the hole 33a. A GRIN lens 56 is built inside the pin 55a, which is located in the middle of the optical path OP2 from the receiving optical fiber 4b to the light-receiving element 7.

Description

Technical Field

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[0001] The present invention relates to an optical transceiver module.

Background Art

[0002] As a conventional optical transceiver module of this type, the one disclosed in Patent Document 1 has been proposed. In this Patent Document 1, the optical transceiver module includes an optical waveguide (optical fiber) for propagating an optical signal, a lens element (lens member) integrally having a lens and a mirror, a support on which the optical waveguide and the lens element are fixed, and a substrate on which the support is fixed. Further, in Patent Document 1, alignment of at least one of the optical waveguide (optical fiber) and the lens element (lens member) with the support is performed by passive alignment, and alignment of the support and the substrate is performed by active alignment.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0007] According to the present invention, it is possible to provide an optical transceiver module that can suppress an increase in the number of components. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing an example of an optical transceiver module according to this embodiment. [Figure 2] This is a perspective view of the optical transceiver module according to this embodiment, seen from the back. [Figure 3] This is an exploded perspective view of the optical transceiver module according to this embodiment. [Figure 4] This is an exploded perspective view of the optical transceiver module according to this embodiment, seen from the back. [Figure 5] This is a schematic plan view of the optical transceiver module according to this embodiment. [Figure 6] This is a cross-sectional view taken along line AA in Figure 5. [Figure 7] Figure 5 is a cross-sectional view taken along the line BB. [Figure 8] This is a side view of the optical transceiver module according to this embodiment. [Figure 9] This is a front view of the optical transceiver module according to this embodiment. [Figure 10]This is a plan view of the optical transceiver module according to this embodiment, seen from the back side. [Figure 11] This is a perspective view of an optical fiber. [Figure 12] This is a side view of an optical fiber. [Figure 13] This is a plan view of a substrate. [Figure 14] This is a side view of a substrate. [Figure 15] This is a perspective view of an optical transceiver module according to another embodiment. [Figure 16] This is a perspective view of an optical transceiver module according to another embodiment, seen from the back side. [Figure 17] This is an exploded perspective view of an optical transceiver module according to another embodiment. [Figure 18] This is a plan view of an optical transceiver module according to another embodiment. [Figure 19] This is a front view of an optical transceiver module according to another embodiment. [Figure 20] This is a perspective view of an optical transceiver module according to yet another embodiment. [Figure 21] This is a perspective view of an optical transceiver module according to yet another embodiment, seen from the back side. [Figure 22] This is an exploded perspective view of an optical transceiver module according to yet another embodiment. [Figure 23] This is a plan view of an optical transceiver module according to yet another embodiment. [Figure 24] This is a front view of an optical transceiver module according to yet another embodiment. [Figure 25] This is an exploded perspective view of an optical transceiver module according to another embodiment.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, the optical transceiver module according to this embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0010] As shown in Figures 1 to 10, the optical transceiver module 1 according to this embodiment comprises a lens unit 2 and a substrate 3. The optical transceiver module 1 is also referred to as an optical coupler or optical coupling module.

[0011] The lens unit 2 is an integrated unit comprising a transmitting optical fiber 4a, a receiving optical fiber 4b, and a lens member 5. In other words, the lens unit 2 is composed of a transmitting optical fiber 4a, a receiving optical fiber 4b, and a lens member 5.

[0012] The material of the lens member 5 can be a lens material with low loss for the wavelength used (for example, quartz glass, resin material, etc.). An inclined surface 51 with a 45-degree inclination angle is formed at the tip of the lens member 5.

[0013] The lens member 5 has a transmitting-side structure 52 on which the transmitting optical fiber 4a is arranged, and a receiving-side structure 53 on which the receiving optical fiber 4b is arranged. These transmitting-side structure 52 and receiving-side structure 53 are arranged side by side in the width direction of the optical transceiver module 1. In this embodiment, the position of the transmitting-side structure 52 with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b is the same as the position of the receiving-side structure 53 with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b. That is, the position of the transmitting optical fiber 4a with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b is the same as the position of the receiving optical fiber 4b with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b. For this reason, in this embodiment, the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the photodetector element 7 are arranged side by side in the width direction of the optical transceiver module 1 (see Figure 9).

[0014] Such a lens member 5 has a protrusion 54 that is housed in a recess 33 of the substrate 3, which will be described later, and a plurality (three in this embodiment) of positioning pins 55a, 55b, 55c. The number of positioning pins 55a, 55b, 55c is not particularly limited. In this embodiment, one of the three pins 55a, 55b, 55c, pin 55a, is formed on the bottom surface 54a of the protrusion 54. Furthermore, a cylindrical lens portion is built inside the pin 55a formed on the bottom surface 54a of the protrusion 54, and is located in the middle of the optical path OP2 from the receiving optical fiber 4b to the photodetector 7 (see Figure 6). This lens portion can be, for example, a GRIN lens 56, also called a refractive index distribution lens. In other words, on the light-receiving element 7 side, the light emitted from the receiving optical fiber 4b passes through the GRIN lens 56 built inside the pin 55a formed on the protrusion 54 of the lens member 5 and is coupled to the light-receiving element 7.

[0015] Furthermore, a notch 57 is formed at the lower part of the lens member 5 (transmitting side structure 52) to form a predetermined gap G between the light-emitting element 6 (described later) and the lens member 5 (see Figure 9). In addition, a lens 8 that focuses the light emitted from the light-emitting element 6 is positioned in the notch 57 (see Figures 4, 7, and 9). By forming this notch 57, when the lens unit 2 is installed and positioned on the substrate 3, the gap G between the light-emitting element 6 and the lens member 5 (transmitting side structure 52) is automatically adjusted to the optimal level. In other words, when the lens unit 2 and the substrate 3 are assembled, a gap G corresponding to the focal length is automatically created between the light-emitting element 6 and the lens member 5 on the light-emitting element 6 side, and the light emitted from the light-emitting element 6 is coupled to the transmitting optical fiber 4a without loss.

[0016] The transmitting optical fiber 4a is composed of optical fibers 4 as shown in Figures 11 and 12. The structure of the optical fibers 4 constituting the transmitting optical fiber 4a is the same as that of the receiving optical fiber 4b, and details will be described later. In this embodiment, the transmitting optical fiber 4a is housed in the transmitting side storage hole portion 52h, which is a through hole formed in the transmitting side structural portion 52 of the lens member 5 (see Figure 7). By providing a refractive index matching material or adhesive 61 between the transmitting side storage hole portion 52h and the tip of the transmitting optical fiber 4a (see Figure 7), the transmitting optical fiber 4a may be fixed by ensuring that there is no air between the transmitting side storage hole portion 52h and the tip of the transmitting optical fiber 4a. Furthermore, by forming a tapered surface 62 in a part of the transmitting side storage hole portion 52h by tapering or the like (see Figure 7), damage to the tip of the transmitting optical fiber 4a during insertion can be suppressed.

[0017] The receiving optical fiber 4b is composed of optical fibers 4 as shown in Figures 11 and 12. The structure of the optical fibers 4 constituting the receiving optical fiber 4b is the same as that of the transmitting optical fiber 4a, and details will be described later. In this embodiment, the receiving optical fiber 4b is housed in the receiving-side storage hole portion 53h, which is a through hole formed in the transmitting-side structural portion 52 of the lens member 5 (see Figure 6). By providing a refractive index matching material or adhesive material 59 between the receiving-side storage hole portion 53h and the tip of the receiving optical fiber 4b (see Figure 6), the receiving optical fiber 4b may be fixed by ensuring that there is no air between the receiving-side storage hole portion 53h and the tip of the receiving optical fiber 4b. Furthermore, by forming a tapered surface 60 in a part of the receiving-side storage hole portion 53h by tapering or the like (see Figure 6), damage to the tip of the receiving optical fiber 4b during insertion can be suppressed.

[0018] As shown in Figures 11 and 12, the optical fiber 4, as an optical path conversion member, is composed of a core and cladding, and a covering portion 41 that covers the core and cladding. The optical fiber 4 has a bare fiber portion 42 in which the core and cladding are exposed, and a 45-degree cut surface is formed at the tip of this bare fiber portion 42. In this embodiment, the 45-degree cut surface is formed at the tip of the bare fiber portion 42 by polishing the tip of the bare fiber portion 42 to match the inclined surface 51 of the lens member 5. A reflective portion 43 with a metallic reflective coating is formed on the cut surface of this bare fiber portion 42, and the optical path is converted by 90 degrees by this metallic reflective portion 43 or by air.

[0019] As shown in Figures 13 and 14, the substrate 3 has a first surface (front surface 31) and a second surface (back surface 32) that are parallel to each other. The light-emitting element 6 is mounted on the first surface (front surface 31), and the light-receiving element 7 is mounted on the second surface (back surface 32). By mounting the light-emitting element 6 and the light-receiving element 7 on different surfaces of the substrate 3, rather than mounting them on the same surface of the substrate 3, the effects of electrical crosstalk (interference) and heat generation from the elements can be suppressed.

[0020] Furthermore, the surface 31 of the substrate 3 has a recess 33 and a plurality (two in this embodiment) of positioning holes 33b and 33c. Of these two positioning holes 33b and 33c, a pin 55b is inserted into hole 33b and a pin 55c is inserted into hole 33c. In addition, in this embodiment, a hole 33a into which a positioning pin 55a is inserted is formed in the bottom wall portion 34 of the recess 33.

[0021] In this embodiment, the recess 33 has a rectangular bottom wall portion 34 in plan view and four side wall portions 35a, 35b, 35c, and 35d surrounding the bottom wall portion 34. Of the four side wall portions 35a, 35b, 35c, and 35d, three side wall portions 35a, 35b, and 35c are formed as inclined surfaces. Also, of the four side wall portions 35a, 35b, 35c, and 35d, only side wall portion 35d is formed as a vertical surface. By forming the three side wall portions 35a, 35b, and 35c as inclined surfaces, when assembling the lens unit 2 and the substrate 3, pressing the lens unit 2 against the substrate 3 positions the recess 33 and the protrusion 54 of the lens unit 2 with an accuracy of several tens of micrometers. As a result, the positioning pins 55a, 55b, and 55c are automatically inserted into the corresponding holes 33a, 33b, and 33c, respectively.

[0022] For example, the lens unit 2 and the substrate 3 can be fixed together by irradiating the transparent lens member 5 with ultraviolet light while an ultraviolet-curing resin is interposed between the lens unit 2 and the substrate 3.

[0023] As described above, the optical transceiver module 1 according to this embodiment comprises a lens unit 2 having a transmitting optical fiber 4a and a receiving optical fiber 4b and a lens member 5, and a light-emitting element 6 that emits an optical signal to the transmitting optical fiber 4a. The optical transceiver module 1 comprises a light-receiving element 7 that receives an optical signal from the receiving optical fiber 4b, and a substrate 3 having a first surface (front surface 31) and a second surface (back surface 32) that are parallel to each other, and to which the light-emitting element 6 and the light-receiving element 7 are attached. A recess 33 is formed on the first surface (front surface 31) of the substrate 3, and a positioning hole 33a is formed on the bottom wall portion 34 of the recess 33. A convex portion 54 that is housed in the recess 33 is formed on the lens member 5, and a positioning pin 55a that is inserted into the hole 33a is formed on the bottom surface portion 54a of the convex portion 54. Inside the pin 55a is a columnar lens portion (GRIN lens 56) located in the middle of the optical path OP2 from the receiving optical fiber 4b to the light-receiving element 7.

[0024] In this embodiment, since the lens unit 2 integrates the transmitting optical fiber 4a, the receiving optical fiber 4b, and the lens member 5, there is no need to add a support for the optical fiber 4, thus suppressing an increase in the number of parts. Furthermore, when assembling the lens unit 2 and the substrate 3, pressing the lens unit 2 against the substrate 3 automatically inserts the positioning pins 55a into the holes 33a, thereby positioning the lens unit 2 and the substrate 3. This does not lead to an increase in the assembly process, and it is possible to suppress a decrease in the productivity of the optical transceiver module 1.

[0025] As described above, according to this embodiment, it is possible to provide an optical transceiver module 1 that can suppress an increase in the number of components.

[0026] In the optical transceiver module 1, the recess 33 may have a bottom wall portion 34 and four side wall portions 35a, 35b, 35c, and 35d surrounding the bottom wall portion 34. Of the four side wall portions 35a, 35b, 35c, and 35d, three side wall portions 35a, 35b, and 35c may be formed as inclined surfaces.

[0027] By forming the three side walls 35a, 35b, and 35c as inclined surfaces, when assembling the lens unit 2 and the substrate 3, pressing the lens unit 2 against the substrate 3 positions the recess 33 and the protrusion 54 of the lens unit 2 with an accuracy of several tens of micrometers. As a result, the positioning pins 55a are automatically inserted into their respective corresponding holes 33a, enabling highly accurate positioning of the lens unit 2 and the substrate 3.

[0028] In the optical transceiver module 1, the light-emitting element 6 may be mounted on the first surface (front surface 31) of the substrate 3, and the light-receiving element 7 may be mounted on the second surface (back surface 32) of the substrate 3.

[0029] By mounting the light-emitting element 6 and the light-receiving element 7 on different sides of the substrate 3, rather than on the same side of the substrate 3, electrical crosstalk and the effects of heat generation from the elements can be suppressed.

[0030] The following describes an optical transceiver module based on a modified example.

[0031] As shown in Figures 15 to 19, in the optical transceiver module 1A according to another embodiment, the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7 are arranged alternately in the extending direction (front-to-back direction) of the optical fiber 4. That is, the position of the transmitting-side structure 52 with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b is different from the position of the receiving-side structure 53 with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b. Also, the position of the transmitting optical fiber 4a with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b is different from the position of the receiving optical fiber 4b with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b.

[0032] In the optical transceiver module 1A shown in Figures 15 to 19, the optical path OP2 of the light-receiving element 7 is positioned closer to the front end of the lens unit 2 than the optical path OP1 of the light-emitting element 6, and the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7 are arranged alternately in front and behind each other. However, conversely, the optical path OP1 of the light-emitting element 6 may be positioned closer to the front end of the lens unit 2 than the optical path OP2 of the light-receiving element 7, and the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7 may be arranged alternately in front and behind each other.

[0033] Thus, in the optical transceiver module 1A, the lens member 5 may have a transmitting-side structure 52 on which the transmitting optical fiber 4a is arranged, and a receiving-side structure 53 on which the receiving optical fiber 4b is arranged. The position of the transmitting-side structure 52 with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b may be different from the position of the receiving-side structure 53 with respect to the extending direction of the transmitting optical fiber 4a and the receiving optical fiber 4b.

[0034] In the optical transceiver module 1A, in which the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7 are arranged alternately in front and behind, crosstalk (interference) and stray light within the lens unit 2 can be reduced, thereby suppressing degradation of signal quality.

[0035] As shown in Figures 20 to 24, in the optical transceiver module 1B according to yet another embodiment, an air layer formed by a slit 58 is provided between the transmitting structure 52 and the receiving structure 53. Furthermore, a shielding member (not shown), such as a shielding sheet or a light absorbing sheet, may be provided in the slit 58 between the transmitting structure 52 and the receiving structure 53.

[0036] Thus, in the optical transceiver module 1B, the lens member 5 may have a transmitting-side structure 52 on which a transmitting optical fiber 4a is arranged, and a receiving-side structure 53 on which a receiving optical fiber 4b is arranged. An air layer or a shielding member may be provided between the transmitting-side structure 52 and the receiving-side structure 53.

[0037] In the optical transceiver module 1B, which has an air layer (slit 58) between the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7, light crosstalk (interference) and stray light within the lens unit 2 can be reduced, thereby suppressing degradation of signal quality. The refractive index of air is approximately 1.0003, while the refractive index of the lens material, such as quartz glass, is approximately 1.5 to 1.6. Due to the difference in refractive index between the air layer and the lens material 5, the direction of light propagation changes, thus physically separating the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7. Furthermore, by providing a shielding member such as a shielding sheet or light-absorbing sheet between the optical path OP1 of the light-emitting element 6 and the optical path OP2 of the light-receiving element 7, the effects of light crosstalk can be reduced.

[0038] As shown in Figure 25, in the optical transceiver module 1C according to another embodiment, a shielding sheet 70 having a through hole 70h into which a GRIN lens 56 can be inserted is sandwiched between the convex portion 54 of the lens member 5 and the recess 33 of the substrate 3. By sandwiching the shielding sheet 70 between the convex portion 54 and the recess 33 of the substrate 3, the crosstalk (interference) and stray light between the light-emitting element 6 and the light-receiving element 7 generated within the lens unit 2 can be further reduced.

[0039] Although not shown in the diagram, it is also possible to use a structure in which the optical fiber 4 is not used as an optical path conversion member, and the inclined surface 51 formed at the tip of the lens member 5 is used as a reflective surface to convert the optical path by 90 degrees.

[0040] Although this embodiment has been described above, this embodiment is not limited to these, and various modifications are possible within the scope of the gist of this embodiment. [Explanation of symbols]

[0041] 1 Optical Transceiver Module 2 Lens Units 3 circuit boards 4a Transmitting optical fiber 4b Receiving infrared 5 Lens components 6 light-emitting elements 7. Photodetector 31 Surface 32 Back side 33 Recess 33a hole 34 Bottom wall section 35a,35b,35c,35d Side wall part 52 Transmitter-side structure 53 Receiving side structure 54 Convex part 54a Bottom part 55a pin 56 GRIN lens OP2 optical path

Claims

1. A lens unit having a transmitting optical fiber, a receiving optical fiber, and a lens member, A light-emitting element that emits an optical signal to the aforementioned transmitting optical fiber, A light-receiving element that receives the optical signal from the receiving optical fiber, A substrate having a first surface and a second surface parallel to each other, on which the light-emitting element and the light-receiving element are attached, A recess is formed on the first surface of the substrate, and a positioning hole is formed in the bottom wall of the recess. The lens member has a protrusion that is housed in the recess, and a positioning pin is formed on the bottom surface of the protrusion that is inserted into the hole. Inside the aforementioned pin, a columnar lens portion is incorporated, located in the optical path from the receiving optical fiber to the photodetector. Optical transceiver module.

2. The recess has a bottom wall portion and four side wall portions surrounding the bottom wall portion, Of the four side wall portions, three are formed as inclined surfaces. The optical transceiver module according to claim 1.

3. The light-emitting element is mounted on the first surface of the substrate. The light-receiving element is mounted on the second surface of the substrate. The optical transceiver module according to claim 1 or 2.

4. The aforementioned lens member, The transmitting side structure in which the aforementioned transmitting optical fiber is arranged, The receiving side structure comprises a receiving optical fiber on which the receiving optical fiber is arranged, The position of the transmitting-side structure with respect to the extending direction of the transmitting optical fiber and the receiving optical fiber is different from the position of the receiving-side structure with respect to the extending direction of the transmitting optical fiber and the receiving optical fiber. The optical transceiver module according to claim 1 or 2.

5. The aforementioned lens member, The transmitting side structure in which the aforementioned transmitting optical fiber is arranged, The receiving side structure comprises a receiving optical fiber on which the receiving optical fiber is arranged, An air layer or shielding sheet is provided between the transmitting structure and the receiving structure. The optical transceiver module according to claim 1 or 2.

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