1. An optical transrnitterlreceiver apparatus comprising: a case including a base and a cover; 5 a circuit board that is housed in said case and is fixed to said base; and an optical module that is housed in said case and is arranged on a side opposite to said base relative to said circuit board, wherein said optical module is fixed to said cover. 10 2. The optical transmitterlreceiver apparatus according to claim 1, comprising: a hole portion provided in one of said circuit board and said optical module; and a pin provided at the other of said circuit board and said optical module so as to be coaxial to said hole portion, said pin being insertable into and removable from said hole portion. 15 3. The optical transmitterlreceiver apparatus according to claim 1 or 2, comprising a plate provided between said optical module and said cover, said plate being fixed to said optical module, wherein said plate is fixed to said cover via a screw inserted from outside of said cover. I 2 0 4. The optical transmitterlreceiver apparatus according to claim 3, wherein said pin is provided at said circuit board; and wherein said hole portion having a shape corresponding to said pin is formed in a fixing member that fixes said optical module and said plate to each other. 2 5 5. The optical transmitterlreceiver apparatus according to claim 3, wherein said hole portion is provided in said circuit board; and wherein said pin having a shape corresponding to said hole portion is formed at a fixing member that fixes said optical module and said plate to each other. 3 0 6. The optical transmitterlreceiver apparatus according to any one of claims 1 to 5, wherein said optical module is electrically connected to said circuit board via a flexible wiring board. I

7. A method of manufacturing an optical transmitterlreceiver apparatus, the method comprising steps of: . fixing a circuit board to a base; placing said optical module on said circuit board; and putting a cover on said base and optical module to said cover.

8. The method of manufacturing an optical transrnitterlreceiver apparatus according to claim 7 wherein when fixing said optical module to said cover, said optical module is hoisted up from said circuit board by rotating said screw. 10

9. The method of manufacturing an optical transmitterlreceiver apparatus according to claim 7 or 8, wherein when placing said optical module on said circuit board, a pin provided at one of said circuit board and said optical module is inserted into a hole portion provided in the other of said circuit board and said optical module to position said optical module. 15

10. The method of manufacturing an optical transmitterlreceiver apparatus according to any one of claims 7 to 9, further comprising a step of routing an optical fiber extending from said optical module, on said circuit board, between the step of placing said optical module on said circuit board and the step of fixing said optical module to said cover.

Description
Title of Invention: OPTICAL TRANSMITTERIRECEIVER APPARATUS AND METHOD OF
MANUFACTURING SAME
Technical Field
[OOO 1 ]
The present invention relates to an optical transmitterlreceiver apparatus and a method of
manufacturing the same.
Background Art
[0002]
Optical transmitterlreceiver apparatuses such as optical transceivers each include
respective components and a case that houses the components. Examples of the components
include a circuit board, an optical receiver module and a light-emitting module. In many cases,
optical transmitter/receiver apparatuses are mounted on boards housed side by side in a rack
cabinet. Thus, the cases of the optical transrnitterlreceiver apparatuses are subject to limitations
in outer shape, and the cases generally have flat plate-like shapes. The outer sizes of the optical
transrnitterlreceiver apparatuses are prescribed by industrial standards called "MSA" (Multi-
Source Agreement). In order to provide functions prescribed by the MSA standards, optical
transrnitterlreceiver apparatuses each include a multitude of components.
[0003]
JP 2005-197569A (hereinafter referred to as Patent Literature 1) discloses an optical
transmission module (optical transrnitterlreceiver apparatus) in which a circuit board, an optical
receiver module that receives an optical signal, and an optical transmitter module that transmits
an optical signal are directly fixed to a case. Consequently, heat generated from the circuit
board, the optical receiver module and the optical transmitter module is radiated from the case.
[0004]
JP 2006-1 71 398A (hereinafter referred to as Patent Literature 2) describes that a substrate
is not fixed to a case and that a predetermined surface of an optical module comes into contact
with a predetermined surface of the case and that the optical module is fixed to the case. Heat
generated from the optical module is released through the case.
[0005]
JP 2008-203427A (hereinafter referred to as Patent Literature 3) discloses an optical
module (optical transmitterlreceiver apparatus) including an optical assembly that houses an
optical element tolfrom which an optical signal is inputloutput, and a circuit board electrically
connected to the optical assembly. The optical assembly is arranged at a predetermined
distance from the circuit board, and is electrically connected to the circuit board. The optical
5 assembly is housed in a case. Between the optical assembly and the case, an elastic member
having a heat dissipation property is provided. The optical assembly is fixed to the case via the
elastic member. More specifically, the case includes an upper case and a lower case resulting
from the case being separated into two parts that are upper and lower parts, and the optical
assembly is fixed to the upper case via the elastic member. Furthermore, the circuit board is
10 fixed to the upper case by screws being threadably fitted in screw holes in board support pillars.
Heat generated from the optical assembly is radiated from the upper case.
[0006]
In recent years, with a decrease in size, an increase in capacity and enhancement of
functions, the densities of components mounted in optical transrnitterlreceiver apparatuses are
15 becoming higher and higher. In particular, optical transmitterlreceiver apparatuses that support
100 Gbps or 40 Gbps digital coherent communications have a large number of components
included in the optical transrnitterlreceiver apparatuses, requiring further higher density
mounting. Also, with high density mounting in optical transrnitterlreceiver apparatuses,
enhancement in heat dissipation efficiency of the respective components is demanded. In
2 0 particular, electric components in digital signal processors such as LSI generate a large amount
of heat, and it is desired to suppress the influence of heat from such electric components on the
optical module.
[0007]
It is necessary to house a circuit board and an optical module in a case having a
2 5 predetermined size. Thus, a part of the circuit board is cut out to secure a space where the
optical module is arranged. As described above, an optical transmission module according to
each of Patent Literatures 1 and 2, the size of the circuit board is limited because of the cutout in
the circuit board (see Figure 2 in Patent Literature 1 and Figure 10 in Patent Literature 2).
Consequently, the problem of a decrease in mounting area of the circuit board has arisen.
30 [0008]
In the optical module described in Patent Literature 3, both the circuit board and the
optical assembly are fixed to the upper case. Thus, heat conducted from the optical module to
the upper case may be transferred to the circuit board or heat conducted from the circuit board to
the upper case may be transferred to the optical module. Thus, the heat dissipation propert(ies)
4
of the circuit board andlor the optical module may deteriorate.
[0009]
Accordingly, it is desired to provide an optical transrnitterlreceiver apparatus that can,
while securing a sufficient mounting area of a circuit board, enhance the heat dissipation
5 propert(ies) of the circuit board andlor an optical module and a method for manufacturing the
same.
Citation List
Patent Literature
10 [OOlO]
Patent Literature 1 : JP 2005- 197569A
Patent Literature 2: JP 2006- 17 1398A
Patent Literature 3: JP 2008-203427A
15 Summary of Invention
[OOll]
An optical transmitterlreceiver apparatus according to an exemplary embodiment includes
a case including a base and a cover, a circuit board and an optical module. The circuit board is
housed in the case and is fixed to the base. The optical module is housed in the case, is
2 0 arranged on a side opposite to the base relative to the circuit board, and is fixed to the cover.
[OO 121
A method of manufacturing an optical transmitterlreceiver apparatus according to an
exemplary embodiment includes the steps of: fixing a circuit board to a base, placing an optical
module on the circuit board, and placing a cover on the base and fastening a screw from outside
2 5 of the cover to fix the optical module to the cover side.
[00 1 31
The above configuration enables heat dissipation properties of a circuit board and an
optical module to be enhanced while a sufficient mounting area of the circuit board is secured.
[00 141
30 The above object and other objects, features and advantages of the present invention will
be clarified in the below description with reference to the accompanying drawings illustrating
examples of the present invention.
Brief Description of Drawings
[00 151
Figure 1 is a schematic plan view of an optical transrnitterlreceiver apparatus.
Figure 2 is a schematic plan view of the optical transmitterlreceiver apparatus with a
cover removed.
Figure 3 is a side view of a configuration of a part around an optical module and a circuit
board.
Figure 4 is an exploded view of the part around the optical module and the circuit board.
Figure 5 is a diagram illustrating a state in which a circuit board is fixed to a base.
Figure 6 is a diagram illustrating a state in which an optical module is placed on the
circuit board.
Figure 7 is a schematic cross-sectional diagram illustrating a structure for positioning an
optical module relative to a circuit board.
Figure 8 is a schematic perspective diagram illustrating a structure for positioning the
optical module relative to the circuit board.
Figure 9 is a top view of the base after an excess length of an optical fiber has been
processed.
Figure 10 is a diagram illustrating a state in which the cover has been put on the base.
Figure 11 is a diagram illustrating another structure for positioning an optical module
relative to a circuit board.
Description of Embodiments
[00 161
An exemplary embodiment of the present invention will be described below with
reference to the drawings. The present invention is applicable to optical transmitterlreceiver
apparatuses including a circuit board and an optical module in general.
[00 1 71
An optical transmitterlreceiver apparatus includes a case that houses various components,
a circuit board and an optical module. Figure 1 is a schematic plan view of the optical
transmitterlreceiver apparatus. Figure 2 is a schematic plan view of the optical
transrnitterlreceiver apparatus with the cover removed. Circuit board 1 and optical module 3
are housed in a case.
[0018]
Figure 3 is a side view illustrating a configuration of a part around circuit board 1 and
optical module 3. Figure 4 is an exploded view illustrating a configuration of the part around
circuit board 1 and optical module 3. Case 30 includes base 7 and cover 8. Circuit board 1 is
fixed to base 7 via fixing members 19 such as, for example, screws. In circuit board 1, various
electric components according to the functions of the optical transmitterlreceiver apparatus are
mounted.
[OOl9]
Optical module 3 includes, for example, a laser module and peripheral circuits. Optical
module 3 is arranged at a position closer to cover 8 relative to circuit board 1, the position being
at a distance from circuit board 1. Optical module 3 is electrically connected to circuit board I
via, for example, flexible wiring board 18. More specifically, connector 1 I provided at flexible
wiring board 18 and connector 12 provided at circuit board 1 are connected to each other.
[0020]
Optical fiber 14 extends from optical module 3. In the example illustrated in Figure 2,
optical fiber 14 is connected to optical fiber 16 extending from another optical module 15 via
splicer 17.
[002 11
Optical module 3 is fixed to cover 8 via plate 6. Optical module 3 is fixed to plate 6 via
fixing members 4 such as, for example, screws. Plate 6 is provided between optical module 3
and cover 8, and is directly fixed to cover 8 via screws 10. More specifically, through holes 9
for fixing plate 6 via screws 10 are provided in cover 8. In plate 6, screw holes 13 are provided
at positions corresponding to through holes 9 of cover 8. As described above, in the present
exemplary embodiment, optical module 3 is fixed to cover 8 side via plate 6. Alternatively,
optical module 3 may be directly fixed to cover 8 via, for examples, screws.
[0022]
From the perspective of heat dissipation properties, it is preferable that each of base 7 and
cover 8 are made of a metal. For heat dissipation property enhancement, a plurality of grooves
may be formed at an outer surface of cover 8. Base 7 and cover 8 have a function that radiates
heat conducted from circuit board 1 and optical module 3. In the present exemplary
embodiment, circuit board 1 is fixed to the base 7 side and optical module 3 is fixed to the cover
8 side, enabling heat from both circuit board 1 and optical module 3 to be efficiently released.
[0023]
Circuit board 1 and optical module 3 are spaced apart from each other, and an air layer is
present between circuit board 1 and optical module 3. The air layer also enables prevention of
the influence of heat generated from electric components mounted on circuit board 1 on the
optical module. In particular, if the optical module is an optical module having a light emission
function, for example, a high-power laser module for long-distance transmission or a
wavelength-variable light source module, it is preferable that the optical module be provided at a
distance from circuit board 1 because such optical module generates a large amount of heat.
[0024]
Also, optical module 3 and circuit board 1 arranged in such a manner that optical module
3 and circuit board 1 are vertically spaced apart from each other, eliminate the need to reduce the
size of circuit board 1 in order to secure a space for mounting optical module 3. Accordingly, a
sufficient mounting area of circuit board 1 can be secured.
[0025]
For enhancement in heat dissipation efficiency, it is preferable that each of base 7, cover 8
and plate 6 are made of a metal. In order to efficiently transfer heat from optical module 3 to
the cover, as illustrated in Figure 3, it is preferable that plate 6 be in contact with cover 8.
[0026]
It is preferable that a plurality of pins 2 be provided in circuit board 1. In the present
example, two pins 2 are diagonally provided at circuit board 1. Alternatively, three or more
pins 2 may be provided at circuit board 1.
[0027]
In the present exemplary embodiment, hole portion 5 is formed in a head portion of each
fixing member 4 that fixes optical module 3 and plate 6 to each other. Each hole portion 5
faces a corresponding one of pins 2 provided at circuit board 1 and has a shape corresponding to
the shape of pin 2. Pins 2 are provided coaxially with respective hole portions 5 and have a
shape that is insertable into and removable from respective hole portions 5. Pins 2 and hole
portions 5 may have any shape such as a circular column or a polygonal column. As described
later, pins 2 and hole portions 5 are used for placing optical module 3 on circuit board 1 during
assembly of the optical transmitterlreceiver apparatus.
[0028]
Next, a method for manufacturing an optical transmitterlreceiver apparatus will be
described. First, as illustrated in Figure 5, circuit board 1 is fixed to base 7. Circuit board 1
can be fixed to the base via, for example, screws 19. It is preferable that pins 2 be provided at
circuit board 1.
[0029]
As illustrated in Figure 6, optical module 3 is placed on circuit board 1. As described
above, it is preferable that optical module 3 be fixed to plate 6 via fixing members 4. Figures 7
and 8 illustrate a detailed example of a structure for positioning optical module 3 relative to
circuit board 1. Fixing members 4 that fix optical module 3 and plate 6 to each other each
include head portion 21, column portion 22 and grooved portion 23. Each grooved portion 23
includes a helical groove and is screwed into a corresponding screw hole in plate 6. In each
head portion 21, hole portion 5 having a shape corresponding to that of corresponding pin 2
provided in circuit board 1 is formed.
[0030]
As a result of pins 2 on circuit board 1 being fitted into respective hole portions 5 at head
portions 21 of fixing members 4, optical module 3 is temporarily placed at a predetermined
position on circuit board 1 with plate 6 directed upward. Consequently, optical module 3 is
positioned in a direction parallel to a surface of circuit board 1.
[003 11
As a result of fixing members 4 that fix optical module 3 and plate 6 to each other being
used for placing optical module 3 on circuit board 1, the number of components can be reduced
and a sufficient mounting area for optical module 3 can be secured. However, as necessary,
members for fixing optical module 3 and plate 6 to each other may be provided separately from
members for placing optical module 3 on circuit board 1.
[0032]
Furthermore, optical module 3 and circuit board 1 are electrically connected. More
specifically, connector 1 1 provided at flexible wiring board 18 is connected to connector 12
provided at circuit board 1, whereby optical module 3 is electrically connected to circuit board 1.
[0033]
As illustrated in Figure 9. after placing optical module 3 on circuit board 1, optical fiber
14 extending from optical module 3 is routed on circuit board 1. For example, an excess length
of optical fiber 14 extending from optical module 3 is hereby processed. In the example
illustrated in Figure 9, another optical module 15 is provided on base 7, and optical fiber 14
extending from optical module 3 and optical fiber 16 extending from other optical module 15 are
interconnected by splicer 17.
[0034]
If possible, the routing of optical fiber 14 may be performed before placing optical
module 3 on circuit board 1.
[0035]
Next, as illustrated in Figure 10, cover 8 is put on base 7 and optical module 3 is fixed to
cover 8 via screws 10. More specifically, screws 10 are inserted into respective through holes 9
formed in cover 8 and respective screw holes 13 formed in plate 6 from outside of cover 8, and
plate 6 is fixed to cover 8 via screws 10. At this time, as a result of screws 10 being turned,
plate 6 and optical module 3 fixed to plate 6 are hoisted up from circuit board 1, and move away
from circuit board 1. Consequently, optical module 3 is fixed to cover 8 via plate 6. It is
preferable that screws 10 be tightened until plate 6 comes into contact with the inner surface of
cover 8. Here, it is not necessary that pins 2 be completely removed from hole portions 5.
[0036]
As described above, optical fiber 14 is routed when both circuit board 1 and optical
module 3 are placed on base 7, providing the advantage of being able to easily and correctly
route optical fiber 14.
COO371
If optical fiber 14 is routed when at least one of circuit board 1 and optical module 3 is
fixed to cover 8, optical fiber 14 extends from cover 8 over to base 7. Accordingly, when cover
8 is put on base 7, optical fiber 14 may be displaced or bent. If optical fiber 14 is bent with a
predetermined bend radius or more, optical characteristics of optical fiber 14 may deteriorate or
optical fiber 14 may be broken. According to the manufacturing method according to the
present exemplary embodiment, optical fiber 14 can be routed on circuit board 1 fixed to base 7,
enabling such problem to be avoided.
[0038]
Since optical module 3 and circuit board 1 are electrically connected via a flexible wiring
board, it is normally inconceivable that circuit board 1 would be fixed to the base 7 side on the
one hand, and that optical module 3 would be fixed to the cover 8 side on the other hand.
However, in the manufacturing method according to the present exemplary embodiment, optical
module 3 is finally hoisted up a bit to cover 8 side and fixed to cover 8. Consequently, a
structure in which circuit board 1 is fixed to the base 7 side and optical module 3 is fixed to the
cover 8 side can easily be provided.
[0039]
Figure 11 illustrates another structure for positioning an optical module relative to a
circuit board. In Figure 1 1, hole portions 102 are provided in circuit board 1 and pins 105
having a shape corresponding to the shape of hole portions 102 are provided at optical module 3.
In this case, pins 105 are inserted into respective hole portions 102, whereby optical module 3
can be placed at a predetermined position on circuit board 1. To reduce the number of
components, it is preferable that pins 105 be formed at fixing members 4 that fix optical module
3 and plate 6 to each other.
[0040]
The present application is filed claiming the priority of Japanese Paten Application No.
201 1-202227 filed on September 15,201 1, the entire disclosure of which is hereby incorporated
by reference.
[004 11
5 Although an exemplary embodiment of the present invention has been presented and
described in detail above, it should be understood that the present invention is not limited to the
above exemplary embodiment and various alterations and modifications are possible without
departing from the spirit.
10 Reference Signs List
[0042]
1 circuit board
2 pin
3 optical module
15 4 fixing member
5 hole portion
6 plate
7 base
8 cover
20 9 through hole
10 screw
30 case
We Claim:
1. An optical transrnitterlreceiver apparatus comprising:
a case including a base and a cover;
5 a circuit board that is housed in said case and is fixed to said base; and
an optical module that is housed in said case and is arranged on a side opposite to said
base relative to said circuit board,
wherein said optical module is fixed to said cover.
10 2. The optical transmitterlreceiver apparatus according to claim 1, comprising:
a hole portion provided in one of said circuit board and said optical module; and
a pin provided at the other of said circuit board and said optical module so as to be
coaxial to said hole portion, said pin being insertable into and removable from said hole portion.
15 3. The optical transmitterlreceiver apparatus according to claim 1 or 2, comprising a plate
provided between said optical module and said cover, said plate being fixed to said optical
module,
wherein said plate is fixed to said cover via a screw inserted from outside of said cover.
I 2 0 4. The optical transmitterlreceiver apparatus according to claim 3,
wherein said pin is provided at said circuit board; and
wherein said hole portion having a shape corresponding to said pin is formed in a fixing
member that fixes said optical module and said plate to each other.
2 5 5. The optical transmitterlreceiver apparatus according to claim 3,
wherein said hole portion is provided in said circuit board; and
wherein said pin having a shape corresponding to said hole portion is formed at a fixing
member that fixes said optical module and said plate to each other.
3 0 6. The optical transmitterlreceiver apparatus according to any one of claims 1 to 5, wherein
said optical module is electrically connected to said circuit board via a flexible wiring board.
I
7. A method of manufacturing an optical transmitterlreceiver apparatus, the method
comprising steps of:
.
fixing a circuit board to a base;
placing said optical module on said circuit board; and
putting a cover on said base and
optical module to said cover.
8. The method of manufacturing an optical transrnitterlreceiver apparatus according to claim
7
wherein when fixing said optical module to said cover, said optical module is hoisted up
from said circuit board by rotating said screw.
10
9. The method of manufacturing an optical transmitterlreceiver apparatus according to claim
7 or 8, wherein when placing said optical module on said circuit board, a pin provided at one of
said circuit board and said optical module is inserted into a hole portion provided in the other of
said circuit board and said optical module to position said optical module.
15
10. The method of manufacturing an optical transmitterlreceiver apparatus according to any
one of claims 7 to 9, further comprising a step of routing an optical fiber extending from said
optical module, on said circuit board, between the step of placing said optical module on said
circuit board and the step of fixing said optical module to said cover.