JPH05299698A - Optical fiber link - Google Patents

Abstract

PURPOSE:To realize a small size, compactness and high precision of optical coupling of a link by integrating an optical fiber link used for a part for converting a light signal acquired by various optical devices to an electrical signal at a high speed and by coupling optical fiber and a photoelectric conversion device directly. CONSTITUTION:An optical fiber 1 is connected to a photoelectric conversion device by an optical coupling tube 2. The optical coupling tube 2 is formed by integrating a ferrule part 2a which contains and fixes an optical fiber terminal part and a sleeve part 2b which contains and fixes an optical transmitting part 3b at an end of a photoelectric conversion device 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber link for connecting an optical signal and an electric signal by coupling an optical fiber and a photoelectric conversion device.

[0002]

2. Description of the Related Art As a conventional technique, for example, Japanese Patent Publication No. 63-
There are optical fiber links such as those disclosed in Japanese Patent No. 29431 and 1987 General Conference of IEICE (2287, Short Distance Optical Transmission Link TOML70).

In this example, an optical module (with a connector) and an optical module accommodating a photoelectric conversion device are separated. Optical coupling is performed by fitting (connecting) the optical fiber side connector and device side connector, and electrical connection is realized by soldering the device terminal (lead frame) inserted perpendicular to the optical axis direction to the circuit board. .. In addition, in order to enhance the shielding effect, a conductive filler is mixed with the connector on the optical module side and grounded.

Another example is Japanese Patent Application No. 59-102.
There is a No. 30 optical connector. The optical coupling method is the same as the above example.

In this example, a method of assembling a ferrule for accurately coupling an optical fiber and a photoelectric conversion device on the optical axis is described.

[0006]

By the way, in the conventional optical fiber link of this type, the optical fiber and the photoelectric conversion device are housed in separate optical connectors, and optical coupling is realized by connecting these optical connectors. Was there. Therefore,
Due to the increase in the number of parts of the optical fiber link, there were restrictions on downsizing and cost reduction. In addition, there were many restrictions in realizing high-precision optical coupling. In addition, since the end face of the optical fiber and the surface of the photoelectric conversion device (light transmitting part) are exposed except in the connected state, it is necessary to adopt a dust-proof cap or use an optical connector with a concave end face. Special consideration was required when attaching.

[0007] As a shield measure, some effects can be expected by using an optical connector mixed with a conductive filler, but the effect is smaller than that of a system in which the device package is directly grounded. In addition, if a conductive filler is mixed, it may cause a deterioration in fitting feeling and reliability of the optical connector, and it has not been particularly proven in automobiles.

Since the electrical connection with the circuit board is realized by soldering the terminals (lead frame) of the photoelectric conversion device, the performance of the optical fiber link depends on the quality of the power supply filter circuit and the circuit pattern on the circuit board. There was one side that was hard to use.

The present invention takes note of various problems associated with the structure of the conventional optical fiber link described above, and combines the optical fiber end and the photoelectric conversion device by an integrated optical fiber link. It is an object of the present invention to provide an optical fiber link that is downsized, compacted, and has high accuracy in optical coupling.

[0010]

As a means for solving the above problems, the present invention provides a ferrule for accommodating and fixing an end portion of an optical fiber in an optical fiber link formed by coupling an optical fiber and a photoelectric conversion device. The optical fiber link is formed by coupling the optical fiber and the photoelectric conversion device by an optical coupling cylinder in which the optical fiber and the photoelectric conversion device are housed and fixed to the sleeve portion that houses and fixes the optical transmission portion.

In this optical fiber link, the material of the optical coupling cylinder is metal, and the photoelectric conversion device is a hermetically sealed system package in which the metallic stem and the cap are electrically welded to hermetically seal the element (chip). The structure is such that the optical coupling cylinder and the cap are in contact with each other and electrically connected, and at least one terminal of the photoelectric conversion device is for grounding (GND) and electrically connected with the stem. Is preferred.

In this case, it is preferable that a connector with a lock mechanism is attached to the device accommodating portion of the optical coupling tube to enable connection with the mating connector. Further, it is assumed that a small substrate having electronic components mounted and through holes formed at the same positions as the terminals is mounted on the back surface (terminal side) of the stem of the photoelectric conversion device. Alternatively, on the back surface (terminal side) of the stem of the photoelectric conversion device, mount a small board on which electronic parts are mounted and a through hole is provided at the same position as the terminal, and the protective wall of this small board and the connector with lock mechanism are integrated. It is preferably molded.

[0013]

In the optical fiber link of the present invention having the above-mentioned structure, the optical coupling tube has the ferrule portion for accommodating the optical fiber and the sleeve portion for accommodating the tip portion of the photoelectric conversion device integrated with each other. Will be directly connected to the photoelectric conversion device. If a connection terminal is provided on the sleeve side of the optical fiber link, by connecting this to the mating connector, it is possible to realize a highly accurate photoelectric connection as easy as a normal electrical connection.

[0014]

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

FIG. 1 is a main sectional view of an optical fiber link of the embodiment. In the figure, 1 is an optical fiber, 2 is an optical coupling tube, and 3 is a photoelectric conversion device. The optical fiber 1 and the light transmitting portion 3b of the photoelectric conversion device 3 face each other on the optical axis x,
The optical coupling cylinder 2 holds the positional relationship. The optical fiber 1 is fixed by a caulking portion 2c and an adhesive 2d in a ferrule portion 2a that houses and fixes the optical fiber of the optical coupling tube 2. The fixing method includes a caulking method, an adhesive method, and a combined method. In this embodiment, the combined method is adopted. In order to improve the tensile strength of the optical fiber 1, the reinforcing material 1b (aramid fiber) at the tip of the optical fiber 1 is incorporated, and after peeling the covering material, the reinforcing material 1b is folded back and the core wire 1a is photoelectrically converted. It is effective to face the light transmitting portion 3b (glass) of the conversion device 3 and fix it to the optical coupling tube 2.

On the other hand, the photoelectric conversion device 3 comprises the optical coupling tube 2
The device is fixed by the sleeve part 2b which houses and fixes the light transmitting part at the device tip. The ferrule part 2a and the sleeve part 2b are integrated. As the fixing method, the adhesive 3a is applied to the outer periphery of the photoelectric conversion device 3 excluding the light transmitting portion 3b. In order to improve the optical coupling efficiency, the optical fiber 1 and the photoelectric conversion element (LED / PD) may be adjusted (aligned) on the optical axis X and then fixed. Photoelectric conversion element (LED, PD,
A cap 3 having a stem 3c (header) for mounting a chip 3e such as a one-chip IC with PD) and a light transmitting portion 3b
d is joined by means of electric welding or the like to hermetically seal the IC chip by a hermetic seal system.

The optical coupling tube 2 is made of metal and has a structure in contact with the cap 3d (metal) and has electrical continuity. Further, at least one terminal of the photoelectric conversion device is the ground terminal 3f (G
ND) and has a structure in which it conducts with the stem 3c.
Therefore, the cap 3 excluding the optical coupling cylinder 2 and the light transmitting portion 3b
The d and the stem 3c can be electrically grounded (GND). It should be noted that the portion where the terminal 3g penetrates the base plate of the stem 3c is filled with a glass insulating material 3h so that the base plate and the terminal 3g are insulated from each other.

FIG. 2 shows an example of the back surface of the stem of the photoelectric conversion device 3 and the substrate 5 on which the electronic component 6 is mounted.
Through holes 7 are provided in the board 5 at the same positions as the terminals 3g and 3f of the device, and after the board 5 is inserted, it is soldered and fixed to the device. The electronic component 6 on the substrate is, for example, a capacitor. In the case of the optical receiver, since a very small signal is handled, it is necessary to connect a capacitor (filter) between the power supply and GND as close to the device as possible. It is also possible to pour a resin (potting type mold) in order to protect this electronic component and make the surface height uniform. Further, by integrally molding, it is possible to combine the molding of the connector and the molding for protecting the board.

FIG. 3 shows an example in which the connector 4 is attached to the optical coupling tube 2. This connector 4 is a lock mechanism 4
It has a and can be electrically connected to a device (unit) side connector for connecting the photoelectric conversion device 3. Lock mechanism 4
As shown in the side view of (b), a is a recess of the side-hand side connector when the protrusion 4b is provided on the lock member and the lock member is elastically held and inserted into the side-hand side connector. (Not shown).

According to the above embodiment, since the optical fiber 1 and the photoelectric conversion device 3 are integrated by the optical coupling tube 2 and are housed in the connector 4, the unit substrate 11 is placed on the unit substrate 11 as shown in FIG. It can be electrically connected to the connector 12. In other words, optical fiber communication is used for high-speed data transmission between electronic units, but the connection with the unit is an electrical connection, so be careful of problems peculiar to optical communication (end face protection of optical fiber, devising patterns on unit board, etc.). Instead, it can be treated the same as ordinary telecommunications.

[0021]

As described in detail above, in the optical fiber link of the present invention, since the optical fiber and the photoelectric conversion device are directly connected by the optical coupling tube, highly accurate optical coupling can be easily realized. It has a small number of parts and is effective for downsizing and cost reduction. The optical coupling tube and photoelectric conversion device package are GN
Since it is electrically connected to D, it can be expected to have an excellent effect in terms of noise resistance when used in an optical receiver. Since the entire surface is shielded except the light transmitting part, it is effective in applications requiring high reliability (mainly noise resistance) in the field of automobiles and the like.

Since the optical coupling tube is housed in the connector and the connection with the outside (unit side) is made by electrical connection, problems inherent in optical communication (such as prevention and protection of the end face of the optical fiber) are caused in connection with equipment. Easy to use without the need to consider. Since the substrate on which the power supply filter circuit and the like are mounted is connected to the photoelectric conversion device and housed in the connector, highly reliable electrical connection is possible. Further, it is possible to obtain various advantages such as easy handling because it is not necessary to install a power supply filter on the device side or devise a wiring pattern in consideration of noise resistance characteristics.

[Brief description of drawings]

FIG. 1 is a main sectional view of an optical fiber link according to an embodiment.

FIG. 2 is a partial view of a back surface of a stem of the photoelectric conversion device and a substrate of the same.

FIG. 3 is a schematic diagram in which a connector is provided on the optical fiber link of the above

FIG. 4 is a diagram illustrating a state in which the connector is connected to a unit substrate using the same connector.

[Explanation of symbols]

 1 Optical Fiber 2 Optical Coupling Tube 2a Ferrule Part 2b Sleeve Part 3 Photoelectric Conversion Device 3b Light Transmission Part 3c Stem (Header) 3e Chip 4 Connector 5 Board 6 Electronic Component

Claims (5)

[Claims] 1. In an optical fiber link formed by coupling an optical fiber and a photoelectric conversion device, a ferrule part for housing and fixing a terminal part of the optical fiber and a light transmitting part at the tip of the photoelectric conversion device are housed and fixed. An optical fiber link characterized in that an optical fiber and a photoelectric conversion device are coupled by an optical coupling tube in which a sleeve part for performing the optical coupling is integrated. 2. The optical coupling tube is made of metal, and the photoelectric conversion device is a hermetically sealed package in which a metallic stem and a cap are electrically welded to hermetically seal an element (chip). And a cap are in contact with each other to be electrically conductive, and at least one terminal of the photoelectric conversion device is for grounding (GND) and electrically connected to the stem. The optical fiber link according to claim 1. 3. The optical fiber link according to claim 1 or 2, wherein a connector with a lock mechanism is attached to a device housing portion of the optical coupling tube to enable connection with a mating connector. 4. The photoelectric conversion device, wherein a small substrate having an electronic component mounted and a through hole provided at the same position as the terminal is mounted on the back surface (terminal side) of the photoelectric conversion device.
Optical fiber link described in. 5. A small board having an electronic component mounted and a through hole provided at the same position as the terminal is mounted on the back surface (terminal side) of the photoelectric conversion device, and a protective wall portion of this small board and a connector with a lock mechanism. The optical fiber link according to claim 2, wherein the part and the part are integrally molded.