Optical transceiver

Abstract

This optical transceiver comprises: a photoelectric conversion element 102; a lens 103 through which light that is emitted from the photoelectric conversion element 102 or that is entering the photoelectric conversion element 102 passes; a lens cap 104 in which the lens 103 is embedded; a stub 105 into which an optical fiber 106 for guiding light passing through the lens 103 is inserted and which has one end side attached to the lens cap 104; and a split sleeve 12 which connects the other end side of the stub 105 and one end side of a ferrule 22 through which the optical fiber 2 is inserted, in the state of being butted against each other. The lens cap 104 includes: a recessed part 104C into which one end portion of the stub 105 is inserted; and a step part 104S which has a diameter enlarged from an opening edge portion of the recessed part 104. The step part 104S of the lens cap 104 and a flange 105F of the stub 105 that are both formed of an epoxy resin are bonded by an epoxy adhesive agent 107.

Description

Optical Transceiver

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

[0002] There are known optical transceivers that align a lens on a fiber optical transceiver (FOT) side with a ferrule on an optical connector side via a split sleeve (see, for example, Patent Documents 1 to 3). In the optical transceivers described in Patent Documents 1 to 3, a stub on the FOT side and a ferrule on the optical connector side are connected by a split sleeve.

[0003] Japanese Patent Application Publication No. 2019-28214 Japanese Patent Application Publication No. 2015-12183 Japanese Patent Application Publication No. 2013-246246

[0004] In the optical transceivers described in Patent Documents 1 to 3, the lens and ferrule must be positioned with high precision via a split sleeve, a stub, and a lens holder to suppress optical loss due to misalignment of the optical axis. Furthermore, if the stub and the lens holder are separate members, the adhesive strength between them must be ensured.

[0005] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an optical transceiver that can achieve alignment between a lens and a ferrule and ensure adhesive strength between a stub and a lens holding portion.

[0006] an optical transceiver according to the present invention comprising: a photoelectric conversion element; a lens through which light emitted from or incident on the photoelectric conversion element passes; a light-transmitting member in which the lens is embedded; a stub having a first optical waveguide formed therein for guiding light passing through the lens, the stub having one end along the first optical waveguide attached to the light-transmitting member; and a split sleeve connecting the other end of the stub along the first optical waveguide to one end of a ferrule having a second optical waveguide formed therein, the other end butting against the first optical waveguide;

[0007] According to the present invention, alignment between the lens and the ferrule can be achieved, and the adhesive strength between the stub and the light-transmitting member (lens holding portion) can be ensured.

[0008] Fig. 1 is a perspective view showing an optical transmission device including an optical transceiver and an optical connector according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing a connection state of the optical transmission device shown in Fig. 1. Fig. 3 is a perspective view showing a split sleeve shown in Figs. 1 and 2. Fig. 4 is a cross-sectional view showing the FOT module shown in Figs. 1 and 2.

[0009] The present invention will be described below in accordance with preferred embodiments. Note that the present invention is not limited to the embodiments described below, and the embodiments described below can be modified as appropriate without departing from the spirit of the present invention. In addition, in the embodiments described below, some components are omitted from illustration and description, but for the details of the omitted technologies, publicly known or well-known technologies are applied as appropriate within the scope of not causing any contradictions with the content described below.

[0010] 1 is a perspective view showing an optical transmission device 1000 including an optical transceiver 10 and an optical connector 20 according to an embodiment of the present invention. As shown in this figure, the optical transceiver 10 is connected to an optical cable 1 via the optical connector 20. The optical cable 1 is connected to another optical transceiver (not shown) via another optical connector (not shown). This allows the optical transceiver 10 to be connected to the other optical transceiver via the optical cable 1 so as to be capable of optical transmission.

[0011] The optical transceiver 10 includes an FOT module 100 (see FIG. 2 ), a housing 11 that houses the FOT module 100, and a split sleeve 12. The housing 11 is fixed with bolts 4 to the enclosure (not shown) of a device that performs optical transmission, such as an in-vehicle camera. The split sleeve 12 is attached to the FOT module 100 and disposed within the housing 11.

[0012] The optical connector 20 includes a housing 21 to which the optical cable 1 is attached, and a ferrule 22 (see FIG. 2). The housing 21 detachably fits with the housing 11. The ferrule 22 is attached to the tip of an optical fiber 2 (see FIG. 2). The optical fiber 2 is inserted through the optical cable 1 and the housing 21.

[0013] The housing 11 includes a cylindrical peripheral wall 111 and a rectangular flange portion 112. An engaging protrusion 111A is formed on the outer surface of the peripheral wall 111. Furthermore, insertion holes (not shown) for inserting bolts 4 are formed at the four corners of the flange portion 112.

[0014] The housing 21 has a cylindrical peripheral wall 211 that fits with the peripheral wall 111 of the housing 11, and an engaging portion 212 provided on the outer surface of the peripheral wall 211. When connecting the optical transceiver 10 and the optical connector 20, the peripheral wall 111 of the housing 11 and the peripheral wall 211 of the housing 21 fit with each other, and the engaging portion 212 of the housing 21 engages with the engaging protrusion 111A of the housing 11. The engaging portion 212 is elastically deformable, and elastic deformation allows it to engage with and disengage from the engaging protrusion 111A.

[0015] When connecting the optical transceiver 10 and the optical connector 20, the ferrule 22 is inserted into and fitted into the split sleeve 12. The split sleeve 12 is an elastically deformable cylindrical body (see FIG. 3), and its elastic deformation allows the ferrule 22 to be inserted and removed.

[0016] Fig. 2 is a cross-sectional view showing the connection state of the optical transmission device 1000 shown in Fig. 1. As shown in this figure, the optical connector 20 includes, in addition to the housing 21 and ferrule 22, an optical fiber introduction section 23, a spring 24, a spring receiver 25, a collar 26, a sealing member 27, and the like.

[0017] The optical fiber 2 includes a core 2A and an outer jacket 2B that covers the core 2A, and is inserted through the optical cable 1, the optical fiber introduction section 23, the spring 24, and the spring receiver 25. In addition, a ferrule 22 attached to the tip of the optical fiber 2 is inserted into the split sleeve 12, and thus the tip of the optical fiber 2 is inserted into the split sleeve 12.

[0018] The tip end of the optical fiber 2 (the optical transceiver 10 side) extends in the direction in which the optical connector 20 is inserted into or removed from the optical transceiver 10 (the left-right direction in the figure, hereinafter referred to as the insertion / removal direction). On the other hand, the base end of the optical fiber 2 (the optical cable 1 side) extends in a direction perpendicular to the insertion / removal direction (the up-down direction in the figure). That is, the optical fiber 2 is bent by approximately 90° at the optical fiber introduction section 23.

[0019] The optical fiber introduction section 23 includes a cable attachment section 231 and a spring receiver 232. The optical fiber introduction section 23 is formed in an L-shape, with the cable attachment section 231 extending in a direction perpendicular to the insertion / removal direction and the spring receiver 232 extending in the insertion / removal direction from one end (the upper end in the figure) of the cable attachment section 231.

[0020] The optical fiber introduction portion 23 is attached to the front side (right side in the figure) of the housing 21 in the insertion / removal direction, and the spring receiving portion 232 extends to the rear side (left side in the figure) of the housing 21 in the insertion / removal direction. The cable attachment portion 231 is an axial portion to which one end of the optical cable 1 is attached. The optical fiber 2 is inserted through the axial center of this cable attachment portion 231. The spring receiving portion 232 is also an axial portion to which one end of the spring 24 is attached. The optical fiber 2 is inserted through the axial center of this spring 24.

[0021] The spring 24 is a coil spring and can expand and contract in the insertion / removal direction. A spring receiver 25 is attached to the other end of the spring 24. The spring 24 biases the spring receiver 25 toward the rear in the insertion / removal direction. The optical fiber 2 is also inserted through the spring 24 and the spring receiver 25.

[0022] Here, the base end side (right side in the drawing) of the ferrule 22 is inserted into and fixed in the hole of the spring receiver 25. As a result, the ferrule 22 is biased by the spring 24 toward the rear in the insertion / removal direction.

[0023] The collar 26 is a cylindrical member that is provided inside the peripheral wall 211 and fixed to the housing 21. The optical fiber 2 and the ferrule 22 are inserted through the center of the collar 26.

[0024] The seal member 27 is a cylindrical member that fits into the gap between the housing 21 and the housing 11 to seal the gap between the housing 21 and the housing 11 .

[0025] The FOT module 100 included in the optical transceiver 10 includes a circuit board 101, a photoelectric conversion element 102, a lens 103, a lens cap 104, a stub 105, and an optical fiber 106. The circuit board 101 is a printed wiring board on which various electronic components, such as the photoelectric conversion element 102, are mounted on an insulating substrate. The circuit board 101 is attached to the flange portion 112 of the housing 11 with the surface on which the photoelectric conversion element 102 is mounted facing the optical connector 20.

[0026] The photoelectric conversion element 102 is a light-emitting element such as an LED (Light Emitting Diode) or a VCSEL (Vertical Cavity Surface Emitting Laser), or a light-receiving element such as a PD (Photo Diode). The photoelectric conversion element 102 is disposed on an extension line of a portion of the optical fiber 2 extending in the insertion / removal direction of the core wire 2A (horizontal direction in the drawing).

[0027] The lens 103 faces the photoelectric conversion element 102 and is disposed so as to be located on an extension line of a portion extending in the insertion / removal direction of the core wire 2A of the optical fiber 2. The focal point of the lens 103 is set to match the light emitting surface or light receiving surface of the photoelectric conversion element 102, so that light emitted from the photoelectric conversion element 102 is focused by the lens 103 and enters the optical fiber 106, and light emitted from the optical fiber 106 is focused by the lens 103 and enters the photoelectric conversion element 102. The lens 103 is made of a light-transmitting cured epoxy resin or the like.

[0028] The lens cap 104 is a light-transmitting mass in which the lens 103 is embedded. The lens cap 104 is made of a cured epoxy resin. The material of the lens cap 104 may contain epoxy resin as its main component, and may also contain oxides of nonmetals or transition metals to control optical properties such as refractive index, or other resins to improve heat resistance or adhesiveness.

[0029] Lens cap 104 has a flat surface 104A that abuts against the surface of circuit board 101 on which photoelectric conversion element 102 is mounted, and a stub mounting portion 104B. Lens 103 is embedded in the center of lens cap 104, and stub mounting portion 104B is a recess that is recessed from the opposite side of flat surface 104A to the position of lens 103.

[0030] The stub 105 is an axial member that covers the optical fiber 106 arranged along the axis of the stub 105. The stub 105 is made of a cured epoxy resin. The material of the stub 105 may be mainly composed of epoxy resin, and may contain other resins to improve heat resistance or adhesiveness. The stub 105 includes a sleeve attachment portion 105A and a lens cap attachment portion 105B.

[0031] The optical fiber 106 includes a core 106A and an outer jacket 106B that covers the core 106A, and is inserted through the axis of the stub 105. Furthermore, one end of the optical fiber 106 is inserted into the split sleeve 12 by inserting the sleeve attachment portion 105A of the stub 105 into the split sleeve 12.

[0032] The portion of the core 2A of the optical fiber 2 extending in the insertion / removal direction and the core 106A of the optical fiber 106 are arranged on the same straight line, and their optical axes are aligned. In addition, the lens 103 and the photoelectric conversion element 102 are arranged on an extension line of the core 106A of the optical fiber 106, and their optical axes are aligned.

[0033] The housing 11 is provided with a cylindrical tube portion 113 that houses the stub 105 and the split sleeve 12. This cylindrical tube portion 113 is inserted into and fitted to the inside of the collar 26. The tube portion 113 also restricts movement of the split sleeve 12 toward the optical connector 20.

[0034] 1 and 2. As shown in this figure, the split sleeve 12 is a cylindrical sleeve having a slit 12S formed therein, which extends from one axial end to the other axial end of the split sleeve 12. The split sleeve 12 allows the ferrule 22 to be pulled out by a predetermined pulling force. However, as will be described later, the movement of the split sleeve 12 due to the pulling force is restricted by the housing 11, so that the stub 105 is prevented from being pulled out by the predetermined pulling force. In other words, when the ferrule 22 is pulled out by the predetermined pulling force, the split sleeve 12 remains fixed to the stub 105.

[0035] 4 is a cross-sectional view showing the FOT module 100 shown in FIGS. 1 and 2. As shown in this figure, the sleeve mounting portion 105A is provided at one axial end (right side in the figure) of the stub 105 and is inserted into and fitted with the split sleeve 12. The sleeve mounting portion 105A has a smaller diameter than the axial center portion of the stub 105, and the tip of the split sleeve 12 abuts against the step between the sleeve mounting portion 105A and the axial center portion of the stub 105. In addition, one end (right end in the figure) of the sleeve mounting portion 105A abuts against one end (left end in the figure) of the ferrule 22, thereby abutting one end of the core wire 2A of the optical fiber 2 and one end of the core wire 106A of the optical fiber 106.

[0036] The lens cap attachment portion 105B includes a flange 105F and a protrusion 105C. The protrusion 105C is a cylindrical shaft portion having a smaller diameter than the axially central portion of the stub 105, and the optical fiber 106 is inserted through the shaft center. The flange 105F is a disk-shaped expanded diameter portion formed at the boundary between the protrusion 105C and the axially central portion of the stub 105.

[0037] The stub attachment portion 104B of the lens cap 104 includes a circular recess 104C into which the protrusion 105C is inserted and fitted, and a circular step portion 104S into which the flange 105F is fitted and adhered. The step portion 104S is a recess whose diameter expands from the opening edge of the recess 104C.

[0038] The diameter D1 of the step portion 104S is larger than the diameter D2 of the flange 105F, and the depth T1 of the step portion 104S is larger than the thickness T2 of the flange 105F.

[0039] Here, the gap between the flange 105F and the step portion 104S is filled with epoxy adhesive 107. That is, the flange 105F of the stub 105, which is made of epoxy resin, and the step portion 104S of the lens cap 104, which is made of epoxy resin, are bonded together with the epoxy adhesive 107. Note that the epoxy adhesive 107 only needs to contain epoxy resin as its main component, and may also contain other resins, etc., to improve heat resistance or adhesiveness.

[0040] Here, the flange 105F of the stub 105 and the step portion 104S of the lens cap 104 serve as a reference surface when aligning the optical fiber 106, the lens 103, and the photoelectric conversion element 102. It is desirable to make the area of ​​this alignment reference surface as small as possible from the viewpoint of improving alignment accuracy. However, by making the alignment reference surface smaller, the area of ​​the bonding surface between the flange 105F of the stub 105 and the step portion 104S of the lens cap 104 also becomes smaller, making it difficult to ensure the adhesive strength between the stub 105 and the lens cap 104.

[0041] Therefore, in this embodiment, the stub 105 and the lens cap 104 are both formed from epoxy resin, and the flange 105F of the stub 105 and the step portion 104S of the lens cap 104 are bonded together with epoxy adhesive 107. In other words, bonding materials of the same type with an adhesive of the same type increases the adhesive strength. This makes it possible to reduce the reference surface for alignment, increase alignment accuracy, and ensure the adhesive strength between the stub 105 and the lens cap 104.

[0042] In this embodiment, the cylindrical portion 113 formed on the housing 11 restricts movement of the split sleeve 12 toward the optical connector 20. As a result, when the optical connector 20 is attached to or detached from the optical transceiver 10, the stub 105 remains fixed to the split sleeve 12, and the ferrule 22 is inserted into or removed from the split sleeve 12. This prevents the position of the split sleeve 12 from changing when the optical connector 20 is attached to or detached from the optical transceiver 10, ensuring accurate alignment between the stub 105 and the ferrule 22.

[0043] Furthermore, in this embodiment, the ferrule 22 is biased toward the optical transceiver 10 by the spring 24, which allows the ferrule 22 and the stub 105 to be butted against each other and joined together.

[0044] The present invention has been described above based on the above embodiment, but the present invention is not limited to the above embodiment, and modifications may be made to the above embodiment within the scope of the spirit of the present invention, or publicly known or well-known technologies may be combined as appropriate.

[0045] Here, the features of the above-described embodiments of the optical transceiver according to the present invention will be briefly summarized and listed below in [1] and [2].

[0046] [1] A photoelectric conversion element (102), a lens (103) through which light emitted from the photoelectric conversion element or incident on the photoelectric conversion element passes, a light-transmitting member (104) in which the lens is embedded, a stub (105) having a first optical waveguide (106) formed therein for guiding light passing through the lens, one end side of the stub in a direction along the first optical waveguide attached to the light-transmitting member, and a split sleeve (12) connecting the other end side of the stub in a direction along the first optical waveguide to one end side of a ferrule (22) in a direction along the second optical waveguide in a state where the two end sides are butted against each other, wherein the light-transmitting member comprises: a recess (104C) into which one end side of the stub in a direction along the first optical waveguide is inserted; and a step portion (104S) whose diameter is enlarged from an opening edge portion of the recess, an optical transceiver (10) including an optical connector side housing (21) that accommodates the ferrule, and a housing (11) that accommodates the light-transmitting member, the stub, and the split sleeve, wherein when the optical connector side housing is attached to or detached from the housing, the stub is maintained in a fixed state to the split sleeve, and the ferrule is inserted into or removed from the split sleeve;

[0047] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

[0048] This application is based on a Japanese patent application (Patent Application No. 2023-127547) filed on August 4, 2023, the contents of which are incorporated herein by reference.

[0049] According to the present invention, it is possible to provide an optical transceiver that can achieve alignment between the lens and the ferrule and ensure adhesive strength between the stub and the optically transparent member (lens holder). The present invention, which has such effects, is useful for optical transceivers.

[0050] 2: Optical fiber (second optical waveguide) 10: Optical transceiver 11: Housing 12: Split sleeve 21: Housing (optical connector side housing) 22: Ferrule 102: Photoelectric conversion element 103: Lens 104: Lens cap (light-transmitting member) 104C: Concave portion 104S: Step portion 105: Stub 105C: Convex portion (one end portion) 105F: Flange 106: Optical fiber (first optical waveguide) 107: Epoxy adhesive

Claims

1. An optical transceiver comprising: a photoelectric conversion element; a lens through which light emitted from said photoelectric conversion element or incident on said photoelectric conversion element passes; a light-transmitting member in which said lens is embedded; a stub having a first optical waveguide formed thereon for guiding light passing through said lens, one end side of the stub in a direction along the first optical waveguide attached to said light-transmitting member; and a split sleeve connecting the other end side of the stub in the direction along the first optical waveguide to one end side of a ferrule in a direction along the second optical waveguide in a butted state, said light-transmitting member having: a recess into which one end of the stub in the direction along the first optical waveguide is inserted; and a stepped portion whose diameter is expanded from an opening edge of the recess; said stub having a flange fitted into the stepped portion; said light-transmitting member and said stub being formed of epoxy resin, and said stepped portion and said flange being bonded with an epoxy adhesive.

2. An optical transceiver as described in claim 1, comprising a housing that accommodates the light-transmitting member, the stub and the split sleeve, and an optical connector side housing that accommodates the ferrule is detachable, and when the optical connector side housing is detached from the housing, the stub is maintained in a fixed state in the split sleeve, and the ferrule is inserted into or removed from the split sleeve.

Images