JP2015203830A - optical data link - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive optical data link in which, without applying large stress to a structure constructed by integrally assembling an assembly substrate, an optical receptacle, and an optical coupling member for optically coupling them to each other, the assembly substrate is in thermal contact with a housing while dimension errors of the constituent components are absorbed.SOLUTION: An optical data link comprises: an optical receptacle 6 for receiving an external optical connector; an assembly substrate 9 mounted with a semiconductor optical element and the like; a resin-made optical coupling member 11, in which the optical receptacle 6 is fixed on one end thereof and the assembly substrate 9 is fixed on the another end thereof, for optically coupling the external optical connector to the semiconductor optical element; and a housing for housing the members 6, 9, and 11. The optical receptacle 6 is fixed to the housing. The optical data link further comprises: a thermally conductive gel 12 applied between the housing and the assembly substrate 9; and a frame-shaped member 13 that is bonded to the assembly substrate 9 and covers a periphery of a region applied with the thermally-conductive gel 12.

Description

  The present invention relates to an optical data link having an optical communication function, and more particularly to an optical data link in which an optical element is mounted on an assembly substrate.

  Among optical data links having an optical communication function, one having both an optical signal transmission function and a reception function is called an optical transceiver. In the optical transceiver, a laser diode (Laser Diode: LD) that is a light emitting element and a photo diode (PD) that is a light receiving element are mounted as semiconductor optical elements. An electronic device for driving these semiconductor optical elements is also mounted on the optical transceiver. In high-speed optical communication, heat generation from the above-described semiconductor optical element and electronic device is large, so it is necessary to dissipate heat to avoid heat storage. In the optical transceiver, the simplest and most effective heat dissipation method is a method in which a heating element is brought into thermal contact with a housing that does not need to consider temperature rise and heat is radiated through the housing.

  In a type of optical transceiver having one lane (channel) for transmission and reception, for example, heat is radiated through a casing as follows. In this type of optical transceiver, the semiconductor optical device is built in an optical subassembly (OSA) of a so-called CAN type package or butterfly type package, and the OSA is housed in a housing of the optical transceiver. The OSA package part, that is, the main body, is fixed to the optical transceiver casing in a state where an elastic sheet-like heat conductive cushioning material is sandwiched between the OSA and the casing, thereby absorbing the dimensional error. The OSA and the casing are surely in thermal contact with each other. Thereby, the heat generated in the OSA can be dissipated through the casing.

  The OSA described above has a sleeve that guides the ferrule so that the optical fiber in the ferrule of the optical connector is optically coupled to the semiconductor optical element, in addition to the main body portion containing the semiconductor optical element. The sleeve is fixed to an optical receptacle provided at one end of a casing of the optical transceiver, and the ferrule of the optical connector is inserted into the sleeve when the optical connector is attached to the optical receptacle.

  However, if the OSA needs to fix the two portions of the main body and the sleeve as described above, stress may be applied to the fixed portion when there is a dimensional error, and the optical axis may shift.

  In view of the above points, in the technique disclosed in Patent Document 1, in the optical transceiver having the butterfly-type OSA, a holder that is attached to the optical transceiver casing is provided separately from the optical receptacle to which the OSA sleeve is fixed. The optical receptacle is attached via a holder so that the position relative to the casing can be adjusted. As a result, the OSA main body can be brought into close contact with the optical transceiver housing without mechanical distortion.

In recent years, optical transceivers having a plurality of lanes for transmission and reception have been developed. For example, an optical transceiver compliant with QSFP (Quad Small Form-factor Pluggable), which is a standard for optical transceivers, has a function of transmitting and receiving four lanes of optical signals in parallel.
9 and 10 are diagrams for explaining an example of an optical transceiver compliant with QSFP. FIG. 9 is an exploded cross-sectional view showing only the main part of the optical transceiver.

The optical transceiver 100 of FIG. 9 includes an upper housing 101 and a lower housing 102, and an optical receptacle 103 is fixed to one end of the housing. The optical receptacle 103 receives an MPO connector having an MT ferrule inside.
In the optical transceiver 100, semiconductor optical elements for processing multi-lane optical signals in parallel are provided in an array on an assembly board 105 that is separate from the main circuit board 104.

  Optical coupling between the semiconductor optical element on the assembly substrate 105 and the optical fiber of the MPO connector received in the optical receptacle 103 is performed through the optical axis conversion component 106 and the optical coupling member 107. The optical axis conversion component 106 includes the optical axis of the light emitted from the LD on the assembly substrate 105, the optical axis of the light receiving surface of the PD on the substrate 105, and the optical fiber light of the MPO connector received in the optical receptacle 103. This is for matching the axis, and is fixed to the assembly substrate 105. The optical coupling member 107 optically couples the optical axis conversion component 106 and the optical receptacle 103. The optical receptacle 103 is fixed to one end, and the optical axis conversion component 106 is fixed to the other end.

  FIG. 10 is a cross-sectional view of the vicinity of the assembly substrate 105 of the optical transceiver 100 of FIG. In the optical transceiver 100, as in the above example, as shown in the figure, thermal conductivity is provided between the upper housing 101 and the assembly substrate 105, and between the lower housing 102 and the assembly substrate 105. Assume that the upper casing 101 and the lower casing 102 are assembled with the cushioning material 108 interposed therebetween, and the assembly substrate 105 is fixed to the casing. As a result, the heat generated in the semiconductor components (LD, LD, amplifier, driver, etc.) on the assembly substrate 105 can be converted into the thermally conductive cushioning material 108 and the lower casing 102 (or the upper casing 101) even if there is a dimensional error. Can dissipate heat.

JP 2006-259731 A

  However, in the optical transceiver 100, the assembly substrate 105, the optical axis conversion component 106, the optical coupling member 107, and the optical receptacle 103 are integrally assembled, and this integrated assembly is almost entirely made of resin. Resin is less rigid than metal. The integrated assembly is large in size. Therefore, when the assembly substrate 105 and the optical receptacle 103 are fixed to the housing of the optical transceiver 100, there is a high possibility that the resin portion is damaged and the optical axis is shifted as compared with the case where it is made of metal.

  When the cushioning property of the heat conductive buffer material 108 is increased, the stress due to the deformation of the heat conductive buffer material 108 is reduced, but the heat conductivity, that is, the heat dissipation property is deteriorated.

Although it is possible to apply the method disclosed in Patent Document 1 to the optical transceiver 100, it is necessary to prepare a holder separate from the optical receptacle, and it is also necessary to provide a complicated structure on the optical receptacle side. There is room for improvement in terms of cost.
In the optical transceiver 100, instead of using the heat conductive buffer material 108, a method of applying a heat conductive gel between the lower housing 102 and the assembly substrate 105 is also conceivable. However, in this method, excess gel may wrap around the surface of the assembly substrate 105 (the surface on the upper housing 101 side), and may contaminate the semiconductor optical device or the like.

  The present invention has been made in view of the above-described circumstances, and is configured without applying great stress to a structural product in which an assembly substrate, an optical receptacle, and an optical coupling member for optically coupling these are integrally assembled. An object of the present invention is to provide an inexpensive optical data link that can absorb a dimensional error of a component and can reliably and reliably contact an assembly substrate and a housing.

  The optical data link of the present invention transmits and receives optical signals via an optical cable, and includes an optical receptacle for receiving an external optical connector provided at an end of the optical cable, and a semiconductor optical device mounted on a circuit board. An assembly substrate, an optical receptacle fixed to one end, an assembly substrate fixed to the other end, a resin optical coupling member that optically couples an external optical connector and a semiconductor optical element, an optical receptacle, and an assembly substrate The optical receptacle is fixed to the casing, the optical data link is further applied between the casing and the assembly substrate, and the assembly. A frame-like member that is adhered to the substrate and covers the periphery of the application region of the thermally conductive gel.

  The optical data link includes an optical axis conversion component that reflects an optical signal so that the optical axis of the semiconductor optical element on the assembly substrate coincides with the optical axis of the optical coupling member, and the optical coupling member passes through the optical axis conversion component. And the assembly substrate are fixed, and the assembly substrate has an alignment hole for positioning the photoelectric conversion component with respect to the assembly substrate, the alignment hole is provided outside the application region of the heat conductive gel. It is preferable.

  The optical coupling member may have a form having an MT ferrule that holds an optical fiber that is optically connected to the optical axis conversion component, and another MT ferrule that engages with the optical receptacle, and is attached to the optical receptacle. The external optical connector can be an MPO connector.

  According to the optical data link of the present invention, the assembly substrate, the optical receptacle substrate, and the optical coupling member are integrally assembled to absorb the dimensional error of the component parts without applying a great stress to the structural product. The housing can be reliably contacted thermally and inexpensively. In addition, the surplus heat conductive gel does not wrap around the surface of the assembly substrate and contaminates the semiconductor optical device or the like.

It is an external view which shows an example of the optical data link by this invention. It is a figure which shows the mode inside the optical data link of FIG. It is a perspective view of an optical receptacle, an assembly board, an optical axis conversion component, and an optical coupling member. It is a partial expanded sectional view near the optical coupling member of an optical data link. FIG. 2 is an exploded view of the optical transceiver of FIG. 1. FIG. 2 is an exploded view of the optical transceiver of FIG. 1. FIG. 2 is a side view of the inside of the optical transceiver in FIG. 1 when the distance between the assembly substrate and the lower housing is wide. FIG. 2 is a side view of the inside of the optical transceiver in FIG. 1 when the distance between the assembly substrate and the lower housing is narrow. It is a figure explaining an example of the optical transceiver based on QSFP which is a standard of an optical transceiver. It is a figure explaining an example of the optical transceiver based on QSFP which is a standard of an optical transceiver.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments according to an optical data link of the invention will be described with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes are included within the meaning and range equivalent to the claim. Moreover, in the following description, the structure which attached | subjected the same code | symbol also in different drawing is the same, and the description may be abbreviate | omitted.

FIG. 1 is an external view showing an example of an optical data link according to the present invention.
The optical data link 1 shown in FIG. 1 is a pluggable (hot-swap) type optical transceiver that is attached to an optical communication host device so as to be insertable / removable and has a signal light transmission / reception function. Thus, it conforms to the QSFP standard for transmission and reception. Hereinafter, the optical data link 1 is referred to as an optical transceiver 1.

  The optical transceiver 1 protects an assembly board (to be described later) on which a semiconductor optical element having a photoelectric conversion function is mounted and a main circuit board 2 on which a large number of electronic devices are mounted with a housing 3. The housing 3 is divided into an upper housing 4 and a lower housing 5 with the main circuit board 2 interposed therebetween. The upper casing 4 and the lower casing 5 are made of die-cast metal such as aluminum or zinc alloy in consideration of heat dissipation and electromagnetic wave radiation suppression.

The optical transceiver 1 also has an optical receptacle 6 for attaching an MPO connector attached to the tip of an optical cable (not shown) at one end, and a slider 7 that can slide along the side surface of the housing 3. And a pull tab 8 connected to the slider 7 and operated by the user.
In the following description, the pull tab 8 side and the optical receptacle 6 side of the optical transceiver will be described as the front side, and the opposite side as the rear side.

  A protrusion 71 is formed at the rear end of the slider 7 so as to extend sideways. Further, the slider 7 is bent in the vicinity of the rear end portion. Thus, in a state where the optical transceiver 1 is mounted in the cage of the host device, that is, in a normal state, the tip portion including the protrusion 71 is accommodated in the concave portion 31 on the side wall of the housing 3, and the protrusion 71 is in the housing 3. It does not protrude outward.

  As described above, in a state where the optical transceiver 1 is mounted in the cage of the host device, the protrusion 71 does not protrude outward from the housing 3, and the engagement piece of the cage of the host device and the recess 31 of the housing 3 The rear wall 31a is engaged, and the optical transceiver 1 is latched and fixed to the cage of the host device. When the user pulls the pull tab 8 forward to remove the latched optical transceiver 1 and the slider 7 is slid forward, the rear end portion including the protrusion 71 of the slider 7 is pushed outward. As a result, the engagement between the engagement piece of the cage of the host device and the rear wall 31a of the recess 31 of the housing 3 is released.

FIG. 2 is a diagram illustrating an internal state of the optical transceiver 1 in FIG. 1, and is a perspective view in which the upper housing 4 and the pull tab 8 in FIG. 1 are omitted.
As shown in the figure, the optical transceiver 1 includes an assembly board 9, an optical axis conversion component 10, and an optical coupling member 11 in addition to the main circuit board 2 and the optical receptacle 6 described above.

FIG. 3 is a perspective view of the optical receptacle 6, the assembly substrate 9, the optical axis conversion component 10, and the optical coupling member 11.
The assembly substrate 9 is formed by mounting an element including a semiconductor optical element on a printed circuit board. More specifically, as shown in FIG. 3, an LD chip 9a in which LDs are provided in an array is provided. It is installed. The LD of the LD chip 9a of this example is a surface emitting LD (VCSEL: Vertical Cavity Surface Emitting LD), and emits signal light in a direction perpendicular to the mounting surface of the assembly substrate 9.

Although not shown, the assembly substrate 9 has a PD chip in which PDs are provided in an array arranged in parallel with the LD chip 9a.
The assembly substrate 9 is supplied with elements to be mounted in the vicinity of the LD chip 9a and the PD chip, for example, a driver for driving the LD chip 9a and an output current from the PD chip so as not to be affected by high frequency driving. Electronic devices such as preamplifiers and main amplifiers to be amplified are also mounted.
Electrical connection between the main circuit board 2 and the assembly board 9 is performed by flexible printed circuit boards 2a and 2b (see FIG. 5 described later).

  The optical axis conversion component 10 includes an optical axis of light emitted from the LD chip 9 a on the assembly substrate 9, an optical axis of the light receiving surface of the PD chip on the substrate 9, and an MT ferrule of an MPO connector attached to the optical receptacle 6. This is for making the optical axis coincide with each other. The optical axis conversion component 10 is provided with a reflective surface that forms an angle of 45 ° with the main surface of the assembly substrate 9. Although not shown, the optical axis conversion component 10 includes an optical lens group for converting the diffused light into collimated light and the collimated light as convergent light, the end surface on the optical coupling member 11 side and the assembly substrate 9 side. It is provided on the end face of. This optical axis conversion component 10 is produced by a resin mold.

  The optical coupling member 11 is for optically coupling the optical axis conversion component 10 and the optical receptacle 6, and more specifically, is mounted on the LD chip 9 a and the PD chip on the assembly substrate 9 and the optical receptacle. This is for optically coupling the optical fiber of the MT ferrule of the MPO connector.

FIG. 4 is a partial enlarged cross-sectional view of the vicinity of the optical coupling member 11 of the optical transceiver 1.
As shown in FIG. 11, in the optical coupling member 11, the end surfaces of the two MT ferrules 11a and 11b opposite to the physical contact sides 11c and 11d are connected to each other through a metal plate 11e. The optical fibers between both MT ferrules 11a and 11b are optically coupled. The outer shells of the MT ferrules 11a and 11b are made of resin. The metal plate 11e is for reducing the influence of electromagnetic radiation through the opening 6a of the optical receptacle 6.

Returning to the description of FIG.
The assembly substrate 9 is provided with an alignment hole 9b in the vicinity of the LD chip and the PD chip. On the other hand, guide pins (not shown) protrude from the end surface of the optical axis conversion component 10 on the assembly substrate 9 side. The optical axis conversion component 10 and the assembly substrate 9 are aligned by inserting the guide pin into the alignment hole 9b. In a state where this alignment is performed, the assembly substrate 9 and the optical axis conversion component 10 are fixed by an adhesive.

  An alignment hole (not shown) is also provided on the end surface of the optical coupling member 11 on the optical axis conversion component 10 side, and the guide pin 10a protrudes from the end surface of the optical coupling component 11 on the optical coupling member 11 side. Yes. The optical axis conversion component 10 and the optical coupling member 11 are aligned by inserting the guide pin 10a into the alignment hole. With this alignment, the optical axis conversion component 10 and the optical coupling member 11 are fixed by an adhesive.

  Further, the end of the optical coupling member 11 opposite to the optical axis conversion component 10 side is inserted into a resin optical receptacle 6 called an MPO clip. When the MPO connector provided at the end of the optical cable is attached from the side opposite to the insertion side of the optical coupling member 11 of the optical receptacle 6, the optical receptacle 6 of the optical coupling member 11 is inserted into the alignment hole provided at the tip of the MPO connector. A guide pin 11f provided on the side is inserted. Thereby, the physical contact (PC) between the optical ferrule of the MT connector 11b on the receptacle side of the optical coupling member 11 and the optical ferrule of the MPO connector attached to the optical receptacle 6 can be ensured. The load by the PC is received by the lower housing through the MPO clip to which the MPO connector is attached.

  Since positioning and fixing are performed as described above, in the optical transceiver 1, the signal light emitted from the LD chip 9a is optically coupled to the optical coupling member 11 by the optical axis conversion component 10, and the optical coupling member 11, the optical ferrule of the MPO connector attached to the optical receptacle 6 is optically coupled. Further, the signal light emitted from the optical ferrule of the MPO connector attached to the optical receptacle 6 is transmitted to the optical axis conversion component 10 via the optical coupling member 11, and is transmitted onto the assembly substrate 9 by the optical axis conversion component 10. It is condensed on the PD chip.

FIG. 5 is an exploded view of the optical transceiver 1 of FIG. 1, and the upper housing 4 and the lower housing 5 are shown in cross section.
In the optical transceiver 1, the optical receptacle 6, the optical coupling member 11, the optical axis conversion component 10, and the assembly substrate 9 are fixed as described above, and thus are integrated. This integrated object is fixed to the housing 3 of the optical transceiver 1 by holding the optical receptacle 6 between the upper housing 4 and the lower housing 5.

  Even in such a fixed state, in order to dissipate heat from the assembly board 9 regardless of dimensional errors, the optical transceiver 1 has a thermally conductive gel between the assembly board 9 and the lower housing 5 as shown in FIG. 12 is applied. The optical transceiver 1 also has a frame-like member 13 so that the heat conductive gel 12 does not wrap around the mounting surface of the assembly substrate 9, that is, the surface on the upper housing 4 side.

FIG. 6 is an exploded view of the optical transceiver 1 for explaining the heat conductive gel 12 and the frame-like member 13, and a part of the upper housing 4 and the lower housing 5 are cut away.
The frame-like member 13 is affixed to the lower surface of the assembly substrate 9 so that the heat conductive gel 12 does not wrap around along the surface (hereinafter referred to as the lower surface) on the lower housing 5 side of the assembly substrate 9. It is provided so as to surround the application region of the heat conductive gel 12 on the lower surface.

This frame-shaped member 13 is made of a porous elastic body, and has, for example, a “Katakana name B” shape in which a square hole 13 a is provided in the center of a square sheet, as shown in FIG. 6. An adhesive tape is attached in advance to the surface of the frame-shaped member 13 on the assembly substrate 9 side, and the frame-shaped member 13 is fixed to the lower surface of the assembly substrate 9 with the adhesive tape.
The thickness of the frame-shaped member 13 is such that the frame-shaped member 13 physically contacts the lower housing 5 even when the distance between the assembly substrate 9 and the lower housing 5 is the largest due to a dimensional error. Thickness is preferred.

7 and 8 are side views of the inside of the optical transceiver 1 when the distance between the assembly substrate 9 and the lower housing 5 is wide and narrow, respectively.
It is assumed that a predetermined amount of the heat conductive gel 12 is applied when the optical transceiver 1 is assembled. At this time, as shown in FIG. 7, when the distance between the assembly substrate 9 and the lower housing 5 is large, the thermally conductive gel 12 does not protrude from the hole 13 a of the frame member 13. Further, at this time, as shown in FIG. 8, when the distance between the assembly substrate 9 and the lower housing 5 is narrow, the frame-like member 13 is crushed and the thickness thereof becomes smaller than that in FIG. The conductive gel 12 protrudes from the hole 13 a of the frame member 13. However, since the frame-shaped member 13 and the lower surface of the assembly substrate 9 are bonded together, the protruding heat conductive gel 12a protrudes along the lower housing 5 and therefore does not go around the mounting surface of the assembly substrate 9. .

Since the main heat source of the assembly board 9 is an electronic device such as a driver or a preamplifier, the frame member 13 is attached so that the hole 13a of the frame member 13 is located on the back side of the mounting area of the device. It is turned on.
When the alignment hole 9b of the assembly substrate 9 of FIG. 3 is provided in the application region of the heat conductive gel 12, the heat conductive gel 12 is applied after the guide pins of the optical axis conversion component 10 are inserted into the alignment hole 9b. Even then, there is a possibility that the heat conductive gel 12 may wrap around the mounting surface of the assembly substrate 9 from the gap between the alignment hole 9b and the guide pin. Therefore, it is preferable that the frame-shaped member 13 is pasted so that the holes 13a of the frame-shaped member 13 are not located in the alignment hole forming region. In other words, it is preferable to provide the alignment hole 9b outside the region where the heat conductive gel 12 is applied.

  The present invention is preferably used for an optical transceiver that requires a plurality of optical fibers for a PC at the same time and has a large force required for the PC.

DESCRIPTION OF SYMBOLS 1 ... Optical data link (optical transceiver), 2 ... Main circuit board, 2a, 2b ... Flexible printed circuit board, 3 ... Housing, 4 ... Upper housing, 5 ... Lower housing, 6 ... Optical receptacle, 7 ... Slider , 8 ... Pull tab, 9 ... Assembly substrate, 9a ... LD chip, 9b ... Alignment hole, 10 ... Optical axis conversion component, 11 ... Optical coupling member, 11a ... MT ferrule, 12 ... Thermally conductive gel, 13 ... Frame-shaped member , 13a ... holes.

Claims (4)

An optical data link that transmits and receives optical signals via an optical cable,
An optical receptacle for receiving an external optical connector provided at an end of the optical cable;
An assembly board comprising a semiconductor optical element mounted on a circuit board;
The optical receptacle is fixed to one end, the assembly substrate is fixed to the other end, and a resin optical coupling member that optically couples the external optical connector and the semiconductor optical element;
A housing for housing the optical receptacle, the assembly substrate, and the optical coupling member;
The optical receptacle is fixed to the housing;
The optical data link further includes:
A thermally conductive gel applied between the housing and the assembly substrate;
An optical data link comprising: a frame-like member that is bonded to the assembly substrate and covers a periphery of the application region of the thermally conductive gel. The optical data link includes an optical axis conversion component that reflects the optical signal so that an optical axis of the semiconductor optical element of the assembly substrate coincides with an optical axis of the optical coupling member, and the optical axis conversion component is The optical coupling member and the assembly substrate are fixed via
The assembly substrate has an alignment hole for positioning the photoelectric conversion component with respect to the assembly substrate;
The optical data link according to claim 1, wherein the alignment hole is provided outside a region where the thermally conductive gel is applied.   The optical data link according to claim 2, wherein the optical coupling member includes an MT ferrule that holds an optical fiber optically connected to the optical axis conversion component, and another MT ferrule that engages with the optical receptacle. The optical data link according to claim 1, wherein the external optical connector is an MPO connector.

Images