JP4758397B2 - Module for optical communication - Google Patents

Description

  The present invention relates to an optical communication module, and more particularly to an optical communication module in which optical components are fixed.

  In the field of optical communication devices that have been aimed at miniaturization, a communication device is modularized, and a module (see Patent Document 1) in which an optical component or the like is housed in a case is known. As optical components, TOSA (Transmitter Optical Sub-Assembly), which is an optical transmission unit provided with a light emitting element, and ROSA (Receive Optical Sub-Assembly), which is an optical reception unit provided with a light receiving element, are used. Yes.

In recent years, reducing power consumption is an important matter in modularization. In particular, a TEC (Thermo Electric Cooler) that controls the operating temperature of the laser is mounted inside the optical transmission unit. If the heat transmission property of the optical transmission unit is poor, the TEC required to bring the laser to a desired temperature. As a result, the power consumption of the entire optical communication module increases.
JP 2005-249892 A

  Conventionally, as a method of dissipating the heat generated in the optical transmitter, the heat generated in the optical transmitter can be dissipated to the housing by connecting the optical transmitter and the housing via silicon resin or the like. Yes. However, since silicon resin or the like has low thermal conductivity, it is difficult to sufficiently dissipate the heat generated in the optical transmitter.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical communication module that can efficiently dissipate heat generated in an optical transmission unit and can suppress power consumption. To do.

The present invention provides an optical transmitter that includes a light emitting element and a TEC that controls the temperature of the light emitting element, an optical receiver that includes a light receiving element therein, the optical transmitter, and the optical receiver. Between the optical transmission unit and the housing, and a housing that houses the optical transmission unit and the optical reception unit in a line, and is provided at the interval. A flat metal plate extending between the optical receiver and the housing, and provided between the optical transmitter and the optical receiver and the metal plate to constitute the optical transmitter While absorbing a mechanical tolerance of the optical transmitter and the optical receiver, which is in contact with a surface and extends from between the optical transmitter and the casing to the optical receiver and the casing. Provided between the first connecting member having a lower thermal conductivity than the metal plate, the housing and the metal plate; Extending from between the optical transmitter and the housing to between the optical receiver and the housing, absorbs mechanical tolerances of the optical transmitter and the optical receiver, and more than the metal plate A second connecting member having a low thermal conductivity, and the light transmitting unit, the light receiving unit, and the housing are disposed via the first connecting member, the metal plate, and the second connecting member. An optical communication module characterized by being thermally connected. According to the present invention, since the optical transmitter and the housing are thermally connected via the metal plate having high thermal conductivity, the heat generated in the optical transmitter can be efficiently radiated to the housing. it can. For this reason, it becomes possible to suppress the power consumption of the module for optical communication.

The said structure WHEREIN: The area of the said metal plate can be set as the structure larger than the area of the said optical transmission part. According to this configuration, the heat generated in the optical transmitter can be radiated to the housing more efficiently.

  The said structure WHEREIN: The thickness of a said 1st connection material can be set as the structure thinner than the thickness of a said 2nd connection material. According to this configuration, the heat generated in the optical transmitter can be radiated to the housing more efficiently.

  According to the present invention, the heat generated in the optical transmitter can be efficiently radiated to the casing by thermally connecting the optical transmitter and the casing via the metal plate having high thermal conductivity. . For this reason, the module for optical communication which can suppress power consumption can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1A is a top view of the optical communication module according to the first embodiment when the cover is seen through, and FIG. 1B is a cross-sectional view taken along a line AA in FIG.

  With reference to FIG. 1A and FIG. 1B, an optical transmitter 12 that is a TOSA having a light emitting element therein and an optical receiver 14 that is a ROSA having a light receiving element therein are aligned. Is housed in a housing 10. The optical transmitter 12 and the optical receiver 14 (hereinafter referred to as optical transmitter / receiver 15) are made of a metal material such as stainless steel, and the casing 10 is made of a metal material such as zinc die cast. Each optical transceiver 15 has a receptacle 16 connected to an optical fiber. A TEC is mounted inside the optical transmitter 12. A circuit board 24 is screwed to the housing 10 using screws 28. A transmission / reception circuit (not shown) is provided under the circuit board 24. The transmission / reception circuit transmits an electrical signal to the optical transmission unit 12, and receives an electrical signal output from the optical reception unit 14 that receives light from the optical fiber and a circuit for transmitting light from the optical transmission unit 12 to the optical fiber. It is a circuit for doing. A cable 30 is provided for connecting the light emitting element in the optical transmitter 12 and the light receiving element in the optical receiver 14 and the transmission / reception circuit to input / output an electric signal. In addition, illustration of the cable 30 is abbreviate | omitted in Fig.1 (a), FIG.1 (b), and FIG.

  An interval 11 of 0.83 mm exists between the optical transceiver 15 and the housing 10. The spacing 11 is provided with a metal plate 18 made of Al (aluminum) and having a thickness of 0.60 mm, and a first connecting material 20 and a second connecting material 22 made of silicone grease and having a thickness of 0.115 mm. The first connecting member 20 is provided between the optical transceiver 15 and the metal plate 18, and the second connecting member 22 is provided between the housing 10 and the metal plate 18. Thereby, the optical transmitter / receiver 15 and the housing 10 are thermally connected via the first connecting member 20, the metal plate 18, and the second connecting member 22. A cover 26 is provided on the optical transceiver 15 and the circuit board 24, and the optical transceiver 15 and the circuit board 24 are protected by the cover 26.

  Next, a method for mounting the optical transceiver 15 in the housing 10 in the optical communication module according to the first embodiment will be described with reference to FIGS. The circuit board 24 is not shown. Referring to FIG. 2A, the fixing device 27 is used to fix the optical transmitter 12 and the optical receiver 14 so that they are aligned with each other. The first connecting material 20 is applied to one surface of the metal plate 18. The surface of the metal plate 18 coated with the first connecting material 20 is connected to the optical transceiver 15. Thereby, as shown in FIG. 2 (b), the optical transceiver 15 and the metal plate 18 are thermally connected via the first connecting member 20.

  With reference to FIG. 3, a hole 32 is provided in the housing 10. The housing 10 and the optical transceiver 15 are fixed by fitting the receptacle 16 of each optical transceiver 15 into the hole 32. Further, the second connecting material 22 is applied to the housing 10 between the metal plate 18 and the housing 10, whereby the housing 10 and the metal plate 18 are thermally connected via the second connecting material 22. Connected to. Therefore, the optical transmitter / receiver 15 and the housing 10 are thermally connected via the first connection member 20, the metal plate 18, and the second connection member 22. In this way, the optical transmission / reception unit 15 is mounted on the housing 10.

  In FIG. 4, the measurement result about the electric power of TEC required in order to keep the temperature of the housing | casing 10 constant in Example 1 and the comparative example 1 is shown. The optical communication module according to Comparative Example 1 is made of silicone grease when the metal plate 18 is not provided between the optical transceiver 15 and the housing 10, that is, between the optical transceiver 15 and the housing 10. This is the case where only the connecting material is provided, and the other configurations are the same as those in the first embodiment. Referring to FIG. 4, when the temperature of the housing 10 reaches a high temperature of 50 ° C. or higher, the TEC power required to keep the housing 10 at a constant temperature is less in the first embodiment than in the first comparative example. I can confirm that.

  In Comparative Example 1, as shown in FIG. 5, the light transmitting unit 12 and the housing 10 are thermally connected via silicone grease provided between the light transmitting unit 12 and the housing 10. From the viewpoint of dissipating the heat generated in the optical transmitter 12, it is preferable to connect the optical transmitter 12 directly to the housing 10. However, since the receptacle 16 of the optical transmission unit 12 is connected to the optical fiber, it is necessary to match the optical axis of the receptacle 16 of the optical transmission unit 12 with the optical axis of the optical fiber. The optical axis of the receptacle 16 of the optical transmission unit 12 may be decentered due to mechanical tolerance due to a lens or the like in the optical transmission unit 12. Therefore, the optical transmitter 12 is not directly connected to the housing 10 so that the mechanical tolerance can be absorbed and the optical axis of the receptacle 16 of the optical transmitter 12 and the optical fiber can be aligned. Connected. Further, in addition to the reason for mechanical tolerance, when versatility is required for the optical transceiver 15 and the housing 10, there is a considerable space between the optical transceiver 15 and the housing 10. For this reason, the optical transmission / reception part 15 and the housing | casing 10 are connected by filling the space | interval of the optical transmission / reception part 15 and the housing | casing 10 with silicone grease. Furthermore, the optical transmission / reception unit 15 and the housing 10 are not directly connected for the reason of improving workability during assembly when the optical transmission / reception unit 15 is housed in the housing 10.

  However, since silicone grease has a low thermal conductivity of 2.5 W / mK, heat dissipation is poor. For this reason, the thermal resistance between the optical transmission part 12 and the housing | casing 10 becomes large, and as shown in FIG. 4, the power consumption of TEC at high temperature becomes large in the comparative example 1. FIG.

  On the other hand, as shown in FIG. 6, in the first embodiment, a metal plate 18 made of Al and a first connecting material 20 and a second connecting material 22 made of silicone grease are provided between the optical transmitter 12 and the housing 10. ing. For this reason, the optical transmitter 12 and the housing 10 are thermally connected via the first connecting member 20, the metal plate 18, and the second connecting member 22. Since the metal plate 18 made of Al has a high thermal conductivity of 238 W / mK, the heat dissipation is excellent. Further, the thickness of the first connecting member 20 and the second connecting member 22 can be reduced by the thickness of the metal plate 18. For this reason, the thermal resistance between the optical transmission part 12 and the housing | casing 10 can be suppressed. Therefore, the heat generated in the optical transmitter 12 can be efficiently dissipated to the housing 10, and the power consumption of the TEC can be suppressed as shown in FIG. Therefore, the optical communication module according to the first embodiment can suppress the power consumption of the entire optical communication module.

  In particular, when the mechanical tolerance due to the lens or the like in the optical transmission unit 12 is large, there are cases where the distance 11 between the optical transmission unit 12 and the housing 10 is narrow or wide. When the distance 11 between the optical transmission unit 12 and the housing 10 is narrow, a connecting material such as silicone grease is provided between the optical transmission unit 12 and the housing 10 as in Comparative Example 1, so that the optical transmission unit 12 is provided. Can efficiently dissipate heat. However, when the distance 11 between the optical transmission unit 12 and the housing 10 is wide, in the structure of Comparative Example 1, the thickness of the connecting material is increased, and the heat dissipation of the optical transmission unit 12 is deteriorated. On the other hand, in the structure of the first embodiment, this can be dealt with by increasing the thickness of the metal plate 18 while keeping the thicknesses of the first connecting member 20 and the second connecting member 22 thin. For this reason, the deterioration of the heat dissipation of the optical transmission part 12 can be suppressed. Thus, according to the first embodiment, even when the mechanical tolerance is large, the thickness of the metal plate 18 can be changed to cope with the deterioration without deteriorating the heat radiation property of the optical transmitter 12. In particular, when the distance 11 between the optical transmission unit 12 and the housing 10 is narrow, it is preferable to provide only the connecting material without providing the metal plate 18 between the optical transmission unit 12 and the housing 10.

Further, the thickness of the first connecting member 20 provided between the light transmitting unit 12 and the light receiving unit 14 and the metal plate 18 is set to the thickness of the second connecting member 22 provided between the housing 10 and the metal plate 18. It is preferable to make it thinner than the thickness .

  Furthermore, even if the area of the metal plate 18 is made larger than the area of the optical transmission unit 12, it can be identified thermally when the package of the optical transmission unit 12 is large, and the heat generated in the optical transmission unit 12 Can be radiated more efficiently.

  Further, the optical receiver 14 is accommodated in the housing 10 so as to be aligned with the optical transmitter 12, and the metal plate 18 extends between the optical receiver 14 and the housing 10, thereby generating in the optical transmitter 12. It is possible to dissipate the heat that has been generated through the optical receiver 14. This is because the optical receiver 14 hardly generates heat.

  In the first embodiment, the first connecting member 20 is provided between the optical transmitter 12 and the optical receiver 14 and the metal plate 18, and the second connecting member 22 is provided between the housing 10 and the metal plate 18. However, the present invention is not limited to this. If at least a connecting material is provided between the optical transmission unit 12 and the optical reception unit 14 and the housing 10, mechanical tolerances due to lenses in the optical transmission unit 12 and the optical reception unit 14 can be absorbed. It is possible to align the optical axis with the optical fiber.

  Further, the metal plate 18 is not limited to Al, and may be any other material as long as it has a high thermal conductivity. Further, the first connecting member 20 and the second connecting member 22 are not limited to silicone grease, and can absorb mechanical tolerances due to the lenses in the light transmitting unit 12 and the light receiving unit 14, and the light transmitting unit 12 and the light receiving unit 14. Other materials may be used as long as the material can be thermally connected to the housing 10. In particular, a material having high thermal conductivity is preferable.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

FIG. 1A is a top view of the optical communication module according to the first embodiment, and FIG. 1B is a cross-sectional view taken along a line AA in FIG. FIGS. 2A and 2B are perspective views (No. 1) for explaining a method of mounting the optical transmission unit and the optical reception unit on the casing. FIG. 3 is a perspective view (No. 2) for explaining a method of mounting the optical transmitter and the optical receiver on the housing. FIG. 4 is a diagram in which the TEC power necessary to keep the temperature of the casing constant is measured. FIG. 5 is a diagram for explaining the problem of the optical communication module according to Comparative Example 1. FIG. 6 is a diagram for explaining the effect of the optical communication module according to the first embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Case 11 Space | interval 12 Optical transmission part 14 Optical reception part 15 Optical transmission / reception part 16 Receptacle 18 Metal plate 20 1st connection material 22 2nd connection material 24 Circuit board 26 Cover 27 Fixing jig 28 Screw 30 Cable 32 Hole

Claims (3)

An optical transmitter internally including a light emitting element and a TEC for controlling the temperature of the light emitting element ;
A light receiving unit having a light receiving element therein;
A housing that is provided so as to have an interval between the optical transmitter and the optical receiver, and that accommodates the optical transmitter and the optical receiver in a line;
A metal plate provided in the interval and extending from between the optical transmitter and the housing to the optical receiver and the housing;
Provided between the optical transmission unit and the optical reception unit and the metal plate, in contact with a flat surface constituting the optical transmission unit, between the optical transmission unit and the housing, the optical reception unit A first connecting member that extends between the housing and absorbs mechanical tolerances of the optical transmitter and the optical receiver and has a lower thermal conductivity than the metal plate;
The optical transmitter and the light, which are provided between the casing and the metal plate and extend from between the optical transmitter and the casing to between the optical receiver and the casing. A second connecting member that absorbs mechanical tolerances of the receiver and has a lower thermal conductivity than the metal plate;
The optical transmitter, the optical receiver, and the housing are thermally connected to each other through the first connecting member, the metal plate, and the second connecting member. module.   The optical communication module according to claim 1, wherein an area of the metal plate is larger than an area of the optical transmission unit.   The optical communication module according to claim 2, wherein a thickness of the first connection member is smaller than a thickness of the second connection member.

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