JP2001291923A - Light transmission-reception module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized light transmit-receive module which does not deteriorate receive sensitivity and will not deteriorate crosstalks between transmit and receive, and can be connected integrally with an optical connector. SOLUTION: The module is constituted of a silicon substrate, whereon a bare chip LD is mounted, a silicon substrate whereon a bare chip PD is mounted, and a plate-like object having light shielding property and conductivity. The plate-like object having light shielding property and conductivity is disposed and constituted, so as to cut off a straight line connecting the bare chip LD and the bare chip PD.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transceiver module. More specifically, the present invention relates to an optical transceiver module in which a bare chip LD and a bare chip PD are mounted on a silicon substrate having a V-groove for positioning and fixing an optical fiber by passive alignment.

[0002]

2. Description of the Related Art An optical transceiver module is an important optical component in an optical transmission system. In recent years, with an increase in the amount of information to be transmitted, there is an increasing demand for faster transmission signals and a smaller optical transceiver module. One of the effective means for miniaturization is the packaged L
D (laser diode) and PD (photodiode)
Instead, an optical transceiver module directly connected to an optical fiber using a bare chip LD or a bare chip PD is employed.

FIG. 6 is a perspective view of a conventional optical transceiver module. 31 is a bare chip LD, 32 is a bare chip P
D and 33 are monitor PD, 34 is LD side V groove, 35 is PD
A side V groove, 36 is an LD side optical fiber, 37 is a PD side optical fiber, 38 is a silicon substrate, 39 is an optical output leaked from the bare chip LD, and 40 is an electromagnetic noise emitted from the bare chip LD.

On a silicon substrate 38, two V-shaped grooves for placing optical fibers are provided, and an LD side V groove 34 and a PD side V groove are provided.
The groove 35 is used. The LD-side optical fiber 36
And the PD side optical fiber 37 is laid.

The bare chip LD 31 is mounted on the tip of the laid LD optical fiber 36, and the bare chip PD 32 is mounted on the tip of the laid PD optical fiber 37. In this case, the core portion of the LD-side optical fiber 36 and the bare chip LD
The depth and location of the LD-side V-groove 34 and the height and location of the bare chip LD31 are adjusted so that the light emitting points of the 31 coincide. Similarly, the PD-side V-groove 3 is set so that the core portion of the PD-side optical fiber 37 coincides with the light receiving point of the bare chip PD32.
5 and the height and the position of the bare chip PD32 are adjusted.

[0006] Bare chip LD31 and bare chip PD3
By mounting 2, the optical transceiver module can be significantly reduced in size. In addition, pair chip LD
Since the position of the bare chip 31 and the bare chip PD32 is determined by the passive alignment, the assembling throughput is increased and the cost is reduced.

Normally, when a bare chip is mounted on an optical transceiver module, a bare chip LD31 and a bare chip PD are used.
32 are mounted on the same plane substrate for mounting in the same process. LD side optical fiber 3 which is an input / output unit for signal light
6 and the PD side optical fiber 37 are also bare chip LD
31 and the bare chip PD32, they are mounted on the same plane substrate for direct connection. After the mounting, the connection between each optical fiber and the bare chip LD and the bare chip PD32 is fixed with resin to complete the optical transceiver module.

[0008]

The conventional optical transmission / reception module has the following problems.

FIG. 7 is a partially enlarged sectional view of the optical transceiver module of FIG. 41 is the light output leaked from the LD-side optical fiber, 42 is the light output from the bare chip LD, and 43 is the light output transmitted through the silicon substrate.

Most of the light emitted from the bare chip LD 31 becomes signal light (represented by the light output 42 from the bare chip LD), but part of the light is reflected by the end face of the LD side optical fiber 36 or the like. The light leaks to the outside without being incident on the light source 36. Such light is bare chip LD
It exists around the entire circumference centering on 31. This light is represented by the light output 39 leaked from the bare chip LD. Further, a part of the light emitted from the bare chip LD 31 transmits through the silicon substrate 43 and becomes an optical output 43 transmitted through the silicon substrate.
Further, part of the light incident on the LD-side optical fiber 36 is:
The light output 41 leaks from the LD-side optical fiber 36 and leaks from the LD-side optical fiber.

Light output 39, L leaked from bare chip LD
The light output 41 leaked from the D-side optical fiber and the light output 43 transmitted through the silicon substrate are so-called stray light, which penetrated the bare chip PD32 and caused deterioration of crosstalk between transmission and reception.

Then, electromagnetic noise is generated from the bare chip LD31, and the electromagnetic noise 40 emitted from the bare chip enters the bare chip PD32, causing deterioration of the receiving sensitivity.

The deterioration of the receiving sensitivity and the deterioration of the crosstalk between transmission and reception described above are caused by the very short distance between the bare chip LD31 and the bare chip PD32 and the mounting on the same plane. This is because optical and electrical isolation with the bare chip PD32 is not ensured.

The completed optical transmitting / receiving module is used by being connected to another optical transmitting / receiving module and an optical cable. Therefore, it is necessary to connect an optical connector to each optical fiber mounted in each V-groove of the optical transceiver module.
Usually, a pigtail connector is connected. As a result, in order to protect the optical fiber fused to the optical transceiver module and maintain the flexibility of this optical fiber, the greatly reduced optical transceiver module becomes large at the time of the package and becomes difficult to handle. was there.

In order to solve this problem, an optical connector, especially a double optical connector (SC type, MT-RJ type, LC
An optical transceiver module having a structure that can be directly connected to the optical connector or a structure that can be integrally connected to the optical connector is required.

Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art, to reduce the receiving sensitivity and the crosstalk between transmission and reception, and to reduce the size of the optical transmission and reception having a structure that can be integrally connected to the optical connector. To provide modules.

[0017]

According to the present invention, a silicon substrate having a bare chip LD mounted thereon, a silicon substrate having a bare chip PD mounted thereon, and a plate-shaped object having light-shielding properties and conductivity are provided. The plate-shaped object having the light-shielding property and the conductivity was arranged so as to block a straight line connecting the bare chip LD and the bare chip PD.

The plate-like object having light-shielding properties and conductivity was a metal plate.

The thickness of the plate-shaped object having light-shielding properties and conductivity is adjusted so that it can be integrally connected to the optical connector.

[0020]

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

FIG. 1 is a perspective view showing a first embodiment of the optical transceiver module of the present invention. 1 is a bare chip LD, 2
Is bare chip PD, 3 is monitor PD, 4 is LD side V groove,
5 is a PD side V groove, 6 is an LD side optical fiber, 7 is a PD side optical fiber, 8 is an LD side silicon substrate, 9 is a PD side silicon substrate, 10 is a metal plate, 11 is an optical output leaked from the bare chip LD, Numeral 12 denotes electromagnetic wave noise emitted from the bare chip LD.

On the LD-side silicon substrate 8, a V-shaped groove for placing an optical fiber and an LD-side V-groove 4 are provided. The LD-side optical fiber 6 is laid in this V-groove. The bare chip LD1 is mounted on the tip of the laid LD-side optical fiber 6. In this case, the core portion of the LD-side optical fiber 6 and the bare chip LD1
The depth and location of the LD-side V-groove 4 and the height and location of the bare chip LD1 are adjusted so that the light-emitting points of (1) and (2) match.

Similarly, a V-shaped groove for placing an optical fiber and a PD-side V-groove 5 are provided on the PD-side silicon substrate 9.
The PD-side optical fiber 7 is laid in the V groove. Laying P
The bare chip PD2 is mounted on the tip of the D-side optical fiber 7. In this case, the depth and location of the PD-side V-groove 5 and the height and location of the bare chip PD2 are adjusted so that the core portion of the PD-side optical fiber 7 and the light receiving point of the bare chip PD2 match.

As described above, the LD-side silicon substrate 8 on which the bare chip LD1 is mounted and the PD-side silicon substrate 9 on which the bare chip PD2 is mounted are prepared, and the surface of each silicon substrate on which the bare chip is not mounted is placed on the metal plate 10.
To form an optical transceiver module.

FIG. 2 is a partially enlarged sectional view of the optical transceiver module of FIG. 13 is an optical output leaked from the LD-side optical fiber, 14 is an optical output from the bare chip LD, 15 is an optical output transmitted through the silicon substrate, and 16 is an optical input to the bare chip PD.

By configuring the optical transceiver module as described above, the optical output 11 leaked from the bare chip LD and the L
The optical output 13 leaked from the D-side optical fiber and the optical output 15 transmitted through the silicon substrate do not enter the bare chip PD2 because the metal plate 10 has a light-shielding property and a conductive property. There is no degradation of crosstalk. In addition, the metal plate 10 serves as the ground of the optical transmitting / receiving module, and the electromagnetic noise 1 emitted from the bare chip LD.
2 is cut off, so that the reception sensitivity can be prevented from deteriorating. The metal plate 10 is preferably a copper plate because it can be soldered and the workability is easy. However, any metal material may be used as long as the elements are not limited.

According to the above configuration, the bare chip LD1 is placed on the LD-side silicon substrate 8 and the bare chip PD
2 are separately mounted on the PD-side silicon substrate 8, so that the number of locations for passive alignment at the time of manufacturing each mounting substrate is reduced, and as a result, the product yield of the optical transceiver module is improved.

FIG. 3 is an explanatory view for assembling the optical transceiver module according to the second embodiment of the present invention. Reference numeral 17 denotes a bare chip LD mounting substrate, and reference numeral 18 denotes a bare chip PD mounting substrate. The bare chip LD and the bare chip PD are mounted on the same silicon substrate (a), and then the silicon substrate is cut between the bare chip LD and the bare chip PD to obtain a bare chip LD mounting substrate 17 and a bare chip PD mounting substrate 18 ( b). Then, the metal plate 10 is bonded to the surface of each silicon substrate on which the bare chip is not mounted (c).

In this embodiment, the same effects as in the first embodiment can be obtained. Further, since the silicon substrate with the bare chip mounted thereon can be manufactured in the same process as the conventional method until the silicon substrate is divided, it can be realized with a small additional investment.

FIG. 4 is an explanatory view of the connection between the optical transceiver module and the optical connector of the first and second embodiments. 19
Is an optical connector. The completed optical transceiver module can be directly connected to the optical connector 19, that is, can be integrally connected to the optical connector 19. Thus, the size of the optical transceiver composed of the optical transceiver module and the optical connector can be further reduced. Further, since the optical fiber used can be very short, the reliability is improved.

If the optical connector 19 is made of metal, the optical connector 19 can be electrically connected to the metal plate 10 of the optical transceiver module to secure a stronger ground. By adjusting the thickness of the metal plate 10 bonded between the bare chip LD mounting board 18 and the bare chip PD mounting board 17, it is possible to integrally connect to another optical connector.

FIG. 5 is an assembly explanatory diagram of a third embodiment of the optical transceiver module of the present invention. Bear chip L
D and the bare chip PD are mounted on the same silicon substrate (a), and then the silicon substrate is cut between the bare chip LD and the bare chip PD, and divided into a bare chip LD mounting substrate 17 and a bare chip PD mounting substrate 18 ( b). The metal plate 10 is placed between the bare chip LD mounting board 17 and the bare chip PD mounting board 18 so that the bare chip LD and the bare chip PD are on the same plane. Even with such a configuration, the same effects as those of the first and second embodiments can be obtained. However, in this case, the light output leaked from the bare chip LD, the light output leaked from the LD-side optical fiber, the light output transmitted through the silicon substrate, and the electromagnetic wave noise emitted from the bare chip LD are generated by the bare chip PD.
It is necessary to set the height of the metal plate 10 so as not to invade the inside.

[0033]

The optical transceiver module of the present invention comprises a silicon substrate on which a bare chip LD is mounted, a silicon substrate on which a bare chip PD is mounted, and a plate-shaped object having light-shielding properties and conductivity. Since the plate-shaped object having the light-shielding property and the conductivity is arranged so as to block a straight line connecting to the bare chip PD, the following effects are exhibited.

(1) It is possible to block stray light from the bare chip LD and prevent crosstalk between transmission and reception from deteriorating.

(2) Electromagnetic noise radiated by the bare chip LD can be suppressed, and deterioration of the receiving sensitivity can be prevented.

(3) It can be connected integrally with the optical connector.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of an optical transceiver module of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the optical transceiver module of FIG. 1;

FIG. 3 is an assembly explanatory diagram of a second embodiment of the optical transceiver module of the present invention.

FIG. 4 is an explanatory diagram of connection between an optical transceiver and an optical connector according to the first and second embodiments.

FIG. 5 is an explanatory view for assembling according to a third embodiment of the optical transceiver module of the present invention.

FIG. 6 is a perspective view of a conventional optical transceiver module.

FIG. 7 is a partially enlarged sectional view of the optical transceiver module of FIG. 6;

[Explanation of symbols]

 Reference Signs List 1 bare chip LD 2 bare chip PD 3 monitor PD 4 LD side V groove 5 PD side V groove 6 LD side optical fiber 7 PD side optical fiber 8 LD side silicon substrate 9 PD side silicon substrate 10 metal plate 11 Light output leaked from bare chip LD 12 Electromagnetic wave noise emitted from bare chip LD 13 Optical output leaked from LD side optical fiber 14 Optical output from bare chip LD 15 Optical output transmitted through silicon substrate 16 Optical input to bare chip PD 17 Bare chip LD mounting board 18 Bare chip PD mounting Substrate 31 Bare chip LD 32 Bare chip PD 33 Monitor PD 34 LD side V-groove 35 PD side V-groove 36 LD side optical fiber 37 PD side optical fiber 38 Silicon substrate 39 Light output leaked from bare chip LD 40 Electromagnetic noise emitted from bare chip LD 41 L Light output through the optical output 43 silicon substrate from the optical output 42 bare LD leaking from the side optical fiber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H037 AA01 BA02 BA11 DA12 DA37 DA40 5F073 AB28 BA01 EA27 FA02 FA07 FA13 FA23 5F088 AA01 BA03 BB01 HA10 HA20 JA03 JA14

Claims (3)

[Claims] 1. A silicon substrate on which a bare chip LD is mounted, a silicon substrate on which a bare chip PD is mounted, and a plate-shaped object having light-shielding properties and conductivity, and blocks a straight line connecting the bare chip LD and the bare chip PD. The optical transmitting and receiving module is configured by arranging the plate-shaped object having the light-shielding property and the conductive property as described above. 2. The optical transmitting and receiving module according to claim 1, wherein the plate-shaped object having light-shielding properties and conductivity is a metal plate. 3. The light according to claim 1, wherein the plate-shaped object having a light-shielding property and a conductive property is configured so that its thickness can be adjusted so as to be integrally connected to the optical connector. Transmit / receive module.