JP2015004860A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module enabling miniaturization in a longitudinal direction.SOLUTION: An optical module 1 includes: a circuit board 24 having an optical element 52 mounted thereon; an electric connector 22 which is connected to the circuit board 24; an optical cable 3 which holds an optical fiber 7; an optical coupling member 55 which is fixed onto the circuit board 24 and optically connects the optical element 52 to the optical fiber 7; and a semiconductor 50 for controlling which is electrically connected to the optical element 52. The semiconductor 50 for controlling includes an element 50b for waveform shaping which is arranged outside of the optical coupling member 55. The optical coupling member 55 is mounted on a first face 24a of the circuit board 24. An element 50b for waveform shaping is mounted on a second face 24b on the opposite side to the first face 24a.

Description

  The present invention relates to an optical module having a circuit board on which an optical element is mounted.

  In recent years, optical modules used in network devices have been increased in number of channels, speed, and size. As an example of an optical module that supports multi-channel, high speed, and miniaturization, an optical element provided on a circuit board, which includes a light receiving element and a light emitting element, and an optical fiber optically connected to the optical element. There is an optical module provided (see Patent Document 1).

JP 2011-112898 A

  In the optical module disclosed in Patent Document 1, a control semiconductor, an optical element, and a lens member covering the optical element are arranged on the same surface on a circuit board. Further, in order to prevent disconnection of the optical fiber optically connected to the optical element, it is necessary to give a certain length to the optical fiber accommodated in the optical module. Therefore, it is difficult to reduce the size of the optical module in the longitudinal direction.

  An object of this invention is to provide the optical module which can be reduced in size in a longitudinal direction.

In order to achieve the above object, the optical module of the present invention comprises:
A circuit board on which an optical element is mounted;
An electrical connector connected to the circuit board;
An optical cable for holding the optical fiber;
An optical coupling member fixed on the circuit board and optically connecting the optical element and the optical fiber;
A control semiconductor electrically connected to the optical element,
The control semiconductor includes a waveform shaping element disposed outside the optical coupling member,
The optical coupling member is mounted on a first surface of the circuit board, and the waveform shaping element is mounted on a second surface opposite to the first surface.

  According to the present invention, it is possible to reduce the size of the optical module in the longitudinal direction.

It is a perspective view which shows the optical module which concerns on this embodiment. It is a perspective view which shows the state which removed the resin housing. FIGS. 3A and 3B are views showing a state in which the metal housing is removed, and FIG. 3A is a view of the substrate as viewed from above, and FIG. 3B is a view of the substrate as viewed from below. 4A is a side view of the substrate shown in FIG. 3, and FIG. 4B is a side view of the substrate according to the conventional example. It is the figure which looked at the board | substrate of the modification 1 from the side. It is the figure which looked at the board | substrate of the modification 2 from the side. FIG. 10 is a partially enlarged cross-sectional view of a substrate according to modification example 3.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.
An optical module according to an embodiment of the present invention is
(1) a circuit board on which an optical element is mounted;
An electrical connector connected to the circuit board;
An optical cable for holding the optical fiber;
An optical coupling member fixed on the circuit board and optically connecting the optical element and the optical fiber;
A control semiconductor electrically connected to the optical element,
The control semiconductor includes a waveform shaping element disposed outside the optical coupling member,
The optical coupling member is mounted on a first surface of the circuit board, and the waveform shaping element is mounted on a second surface opposite to the first surface.
According to this configuration, the length of the circuit board can be shortened, and downsizing in the longitudinal direction of the optical module can be realized.

(2) It is preferable that the region where the waveform shaping element is mounted on the second surface is provided on the back side of the region where the optical coupling member is mounted on the first surface.
According to this configuration, the length of the circuit board can be further shortened.

(3) It is preferable that the optical coupling member is disposed in a region different from the region where the waveform shaping element is mounted on the second surface in the thickness direction of the circuit board.
According to this configuration, it is possible to suppress deterioration in characteristics and lifetime of the optical coupling member and the optical element due to the influence of heat from the waveform shaping element.

(4) An optical fiber holding member that holds the optical fiber exposed from the optical cable and is coupled to the optical coupling member,
The region where the waveform shaping element is mounted on the second surface is preferably provided on the back side of the region where the optical fiber holding member is disposed on the first surface.
According to this configuration, it is possible to reduce the length of the circuit board while suppressing deterioration in characteristics and lifetime of the optical coupling member and the optical element due to the influence of heat from the waveform shaping element.

(5) In the region where the waveform shaping element of the circuit board is mounted, a through portion that penetrates only a part of the circuit board in the thickness direction between the first surface and the second surface. A via hole is preferably provided.
According to this configuration, it is possible to reliably suppress deterioration in characteristics and lifetime of the optical coupling member and the optical element due to the influence of heat from the waveform shaping element.

[Details of the embodiment of the present invention]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  An optical module 1 shown in FIG. 1 is used for transmission of signals (data) in optical communication technology and the like, and is electrically connected to an electronic device such as a personal computer to be connected to input / output electric signals. An optical signal is transmitted after being converted into a signal.

  As shown in FIG. 1, the optical module 1 includes an optical cable 3 and a connector module 5. The optical module 1 is configured by attaching the end of a single-core or multi-core optical cable 3 to a connector module 5. Hereinafter, the electrical connector 22 side will be described as the front side of the optical module 1, and the optical cable 3 side will be described as the rear side as necessary.

  As shown in FIGS. 1 and 2, the optical cable 3 includes a plurality (four in this case) of optical fiber cores (an example of an optical fiber) 7 and a resin outer sheath that covers the optical fiber cores 7. A sheath 9, an ultrafine-diameter tensile strength fiber 11 interposed between the optical fiber core 7 and the outer sheath 9, and a metal braid 13 interposed between the outer sheath 9 and the tensile strength fiber 11. Yes. In the optical cable 3, the optical fiber core wire 7, the tensile strength fiber 11, the metal braid 13, and the jacket 9 are arranged in this order from the center toward the outside in the radial direction.

  As the optical fiber core 7, an optical fiber (AGF: All Glass Fiber) whose core and clad are quartz glass, an optical fiber (HPCF: Hard Plastic Clad Fiber) whose clad is made of hard plastic, or the like can be used. When a thin HPCF having a glass core diameter of 80 μm is used, it is difficult to break even if the optical fiber core wire 7 is bent to a small diameter. The jacket 9 is made of, for example, PVC (polyvinylchloride) which is a non-halogen flame retardant resin. The outer diameter of the jacket 9 is about 4.2 mm. The tensile strength fiber 11 is an aramid fiber, for example, and is built in the optical cable 3 in a bundled state.

  The metal braid 13 is made of, for example, a rectangular tin-plated lead wire, and has a braid density of 70% or more and a knitting angle of 45 ° to 60 °. The outer diameter of the metal braid 13 is about 0.05 mm.

  The connector module 5 includes a housing 20, an electrical connector 22 provided on the front end (tip) side of the housing 20, and a circuit board 24 (see FIG. 3) accommodated in the housing 20.

  The housing 20 includes a metal housing (an example of a housing) 26 and a resin housing 28. The metal housing 26 includes an accommodation member 30 and a fixing member 32 (an example of a cable fixing portion) that is connected to the rear end portion of the accommodation member 30 and fixes the optical cable 3.

  The accommodating member 30 is a cylindrical hollow member having a substantially rectangular cross section, and the circuit board 24 and the like are accommodated therein. An electrical connector 22 is provided on the front end side of the housing member 30, and a fixing member 32 is connected to the rear end side of the housing member 30. After peeling off the jacket 9, the optical fiber core 7 of the optical cable 3 is inserted into the housing member 30, and the fixing member 32 and the metal braid 13 are joined by solder, whereby the optical cable 3 is connected to the housing member 30. Is fixed.

  The resin housing 28 is made of, for example, a resin material such as polycarbonate and covers the metal housing 26. The resin housing 28 includes an exterior housing 44 and a boot 46 connected to the exterior housing 44. The exterior housing 44 is provided so as to cover the outer surface of the housing member 30. The boot 46 is connected to the rear end portion of the exterior housing 44 and covers the fixing member 32 of the metal housing 26.

  The electrical connector 22 is a part that is inserted into a connection target (such as a personal computer) and is electrically connected to the connection target. The electrical connector 22 is disposed on the front end side of the housing 20 and protrudes forward from the housing 20. The electrical connector 22 is electrically connected to the circuit board 24 by a contact 22a.

  The circuit board 24 is accommodated in the metal housing 26 (accommodating member 30). As shown in FIG. 3, the circuit board 24 has a substantially rectangular shape in a plan view and has a predetermined thickness. The circuit substrate 24 is an insulating substrate such as a glass epoxy substrate or a ceramic substrate, and circuit wiring is formed on the surface or inside thereof by gold (Au), aluminum (Al), copper (Cu), or the like. . On the upper surface 24a (an example of the second surface) and the lower surface 24b (an example of the first surface) of the circuit board 24, a control semiconductor 50 and a light emitting / receiving element 52 (an example of an optical element) are respectively mounted. Yes. The circuit board 24 electrically connects the control semiconductor 50 and the light emitting / receiving element 52.

  The control semiconductor 50 includes a drive IC (Integrated Circuit) 50a, a CDR (Clock Data Recovery) device 50b which is a waveform shaper (an example of a waveform shaping element), and the like. As shown in FIG. 3B, the drive IC 50 a is disposed on the lower surface 24 b of the circuit board 24 and is electrically connected to the electrical connector 22. On the other hand, the CDR device 50b is disposed on the upper surface 24a of the circuit board 24 and is electrically connected to the electrical connector 22 as shown in FIG.

  The light receiving / emitting element 52 includes a plurality (here, two) of light emitting elements 52a and a plurality (here, two) of light receiving elements 52b. As shown in FIG. 4A, the light emitting element 52 a and the light receiving element 52 b are arranged on the rear end side of the driving IC 50 a on the lower surface 24 b of the circuit board 24. In this example, the driving IC 50a and the light emitting / receiving element 52 are arranged on the circuit board 24 on the back side of the position where the CDR device 50b is arranged. As the light emitting element 52a, for example, a light emitting diode (LED: Light Emitting Diode), a laser diode (LD: Laser Diode), a surface emitting laser (VCSEL: Vertical Cavity Surface Emitting LASER), or the like can be used. For example, a photodiode (PD) can be used as the light receiving element 52b.

  The light emitting / receiving element 52 is optically connected to the optical fiber core wire 7 of the optical cable 3. As shown in FIG. 3B, a lens array component 55 (an example of an optical coupling member) is disposed on the lower surface 24b of the circuit board 24 so as to cover the light emitting / receiving element 52 and the driving IC 50a. That is, as shown in FIG. 4A, like the driving IC 50a and the light emitting / receiving element 52, the lens array component 55 is also arranged on the circuit board 24 behind the position where the CDR device 50b is arranged. . The lens array component 55 is provided with a reflection portion 55a that reflects the light emitted from the light emitting element 52a or the light emitted from the optical fiber core wire 7. It is preferable that the lens array component 55 includes collimating lenses that convert the incident light into parallel light and collect and emit the parallel light at the light incident portion and the light emission portion. Such a lens array component 55 can be integrally formed by resin injection molding.

  A connector part 54 (an example of an optical fiber holding member) is attached to the end (front end side) of the optical fiber core wire 7, and this connector part 54 is coupled to the rear end side of the lens array part 55. Thereby, the optical fiber core wire 7 and the light emitting / receiving element 52 are optically connected.

  FIG. 4B shows a circuit board 124 according to a conventional example. In the circuit board 124 according to the conventional example, the light emitting / receiving element 52, the driving IC 50a, and the CDR device 50b are all arranged in parallel on the upper surface 124a side. Therefore, the length L2 in the longitudinal direction of the circuit board 124 according to the conventional example needs to be set longer than the length L1 in the longitudinal direction of the circuit board 24 according to the present embodiment shown in FIG. is there.

  In the optical module 1 having the above configuration, an electrical signal is input from the electrical connector 22, and the electrical signal is input to the control semiconductor 50 through the wiring of the circuit board 24. The electrical signal input to the control semiconductor 50 is output from the control semiconductor 50 to the light emitting / receiving element 52 via the wiring of the circuit board 24 after the level is adjusted and the waveform shaping is performed by the CDR device 50b. . The light emitting / receiving element 52 that receives the electric signal converts the electric signal into an optical signal, and emits the optical signal from the light emitting element 52 a to the optical fiber core wire 7.

  Further, the optical signal transmitted through the optical cable 3 is incident on the light receiving element 52b. The light receiving element 52 b converts the incident optical signal into an electrical signal, and outputs the electrical signal to the control semiconductor 50 via the wiring of the circuit board 24. In the control semiconductor 50, the electrical signal is output to the electrical connector 22 after predetermined processing is performed on the electrical signal.

  As described above, in the present embodiment, the lens array component 55 and the light emitting / receiving element 52 are mounted on the lower surface 24b of the circuit board 24, and the CDR device 50b is mounted on the upper surface 24a opposite to the lower surface 24b. Yes. As described above, the lens array component 55 and the CDR device 50b are mounted on different surfaces of the circuit board 24, so that the space on the circuit board 24 can be effectively used. The length can be shortened. Therefore, the housing 20 in which the circuit board 24 is accommodated is shortened, and the optical module 1 can be downsized in the longitudinal direction.

  The region where the CDR device 50b is mounted on the upper surface 24a of the circuit board 24 is provided behind the region where the lens array component 55 is mounted on the lower surface 24b. Thereby, the circuit board 24 can be further shortened.

  FIG. 5 is a side view of the circuit board 224 of the first modification. In the first modification, the area where the lens array component 55 and the light emitting / receiving element 52 are mounted on the lower surface 224b of the circuit board 224 is different from the area where the CDR device 50b is mounted on the upper surface 224a. In the longitudinal direction (left-right direction in FIG. 5), for example, the circuit board 224 is shifted to the rear end side. In other words, the lens array component 55 and the light emitting / receiving element 52 are arranged on the upper surface 224a of the circuit board 224 in different areas in the thickness direction of the circuit board 224 from the area where the CDR device 50b is mounted. Also in this case, the length L3 in the longitudinal direction of the circuit board 224 is shorter than the length L2 in the longitudinal direction of the circuit board 124 according to the conventional example shown in FIG.

  In general, the CDR device 50b generates a larger amount of heat during operation than the drive IC 50a. Therefore, in the first modification, as shown in FIG. 5, the lens array component 55 and the light emitting / receiving element 52 are not arranged on the back side of the region where the CDR device 50b is arranged on the circuit board 224. Thereby, it is possible to suppress the heat discharged from the CDR device 50 b from being transmitted to the lens array component 55 and the light emitting / receiving element 52 via the circuit board 224. For this reason, the length of the circuit board 224 is made shorter than that of the conventional circuit board 124 to reduce the size of the optical module 1, and the characteristics of the lens array component 55 and the light emitting / receiving element 52 are deteriorated due to the influence of heat from the CDR device 50 b. It is possible to prevent a decrease in life.

  FIG. 6 is a side view of the circuit board 324 according to the second modification. In the second modification, the CDR device 50b mounted on the upper surface 324a of the circuit board 324 is provided on the back side of the region where the connector component 54 connected to the lens array component 55 is disposed on the lower surface 324b. Also in this case, the length L4 in the longitudinal direction of the circuit board 324 is shorter than the length L2 in the longitudinal direction of the circuit board 124 according to the conventional example shown in FIG.

  The connector part 54 is a member that holds the optical fiber core wire 7 and is connected to the lens array part 55. However, compared with the lens array part 55 and the light emitting / receiving element 52, the influence of heat from the CDR device 50 b is much considered. do not have to. Therefore, according to the configuration of FIG. 6, as in the first modification, the circuit board of the conventional example is suppressed while suppressing deterioration in characteristics and lifetime of the lens array component 55 and the light emitting / receiving element 52 due to the influence of heat from the CDR device 50 b. The length of the circuit board 324 can be made shorter than that of the circuit board 224 of 124 or Modification 1, and the optical module 1 can be further miniaturized.

  FIG. 7 is a partially enlarged cross-sectional view of the circuit board 424 of the third modification. As shown in FIG. 7, the circuit board 424 is formed in, for example, an eight-layered shape. The circuit board 424 is provided with a plurality of through via holes 25a and 25b for interlayer connection. The through via hole 25a is provided in a region other than the region where the CDR device 50b is disposed, and penetrates all layers from the upper surface 424a to the lower surface 424b of the circuit board 424. On the other hand, the through via hole 25b is provided in the circuit board 424 in a region where the CDR device 50b is disposed. The through via holes 25b are alternately provided with those that pass through, for example, four layers on the upper surface 424a side of the circuit board 424 and those that pass through, for example, four layers on the lower surface 424b side. In other words, in the region of the circuit board 424 where the CDR device 50b is mounted, a through via hole 25b penetrating only a part of the circuit board 424 in the thickness direction is provided between the upper surface 424a and the lower surface 424b.

  The heat generated in the CDR device 50b is transferred to the lower surface 424b side of the circuit board 424 through the through via hole 25b. However, since the through via hole 25b does not penetrate all layers from the upper surface 424a to the lower surface 424b, a structure in which heat is not directly transmitted to the lower surface 424b side where the lens array component 55 and the light emitting / receiving element 52 are disposed. It has become.

  According to this configuration, while maintaining the circuit board 424 at a certain length or less, it is possible to reliably suppress deterioration in characteristics and lifetime of the lens array component 55 and the light emitting / receiving element 52 due to the influence of heat from the CDR device 50b. it can.

  While the 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.

1: Optical module 3: Optical cable 5: Connector module 7: Optical fiber core wire (an example of an optical fiber)
9: Jacket 11: Tensile fiber 13: Metal braid 20: Housing 22: Electrical connector 24: Circuit board 26: Metal housing 28: Resin housing 30: Housing member 32: Fixing member 50: Semiconductor for control 50a: Drive IC
50b: CDR device (an example of a waveform shaping element)
52: Light emitting / receiving element (an example of an optical element)
54: Connector component (an example of an optical fiber holding member)
55: Lens array component (an example of an optical coupling member)
L1 to L4: Length of circuit board

Claims (5)

A circuit board on which an optical element is mounted;
An electrical connector connected to the circuit board;
An optical cable for holding the optical fiber;
An optical coupling member fixed on the circuit board and optically connecting the optical element and the optical fiber;
A control semiconductor electrically connected to the optical element,
The control semiconductor includes a waveform shaping element disposed outside the optical coupling member,
An optical module in which the optical coupling member is mounted on a first surface of the circuit board, and the waveform shaping element is mounted on a second surface opposite to the first surface.   2. The light according to claim 1, wherein the region on which the waveform shaping element is mounted on the second surface is provided on the back side of the region on which the optical coupling member is mounted on the first surface. module.   2. The optical module according to claim 1, wherein the optical coupling member is disposed in a region different from a region where the waveform shaping element is mounted on the second surface in a thickness direction of the circuit board. Holding the optical fiber exposed from the optical cable, further comprising an optical fiber holding member coupled to the optical coupling member;
The region where the waveform shaping element is mounted on the second surface is provided on the back side of the region where the optical fiber holding member is disposed on the first surface. Optical module.   A through via hole that penetrates only a part in the thickness direction of the circuit board is provided between the first surface and the second surface in a region of the circuit board where the waveform shaping element is mounted. The optical module according to claim 1, wherein the optical module is provided.

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