Light transmission module

• US 5,479,288 A
• Filed: 03/08/1993
• Issued: 12/26/1995
• Est. Priority Date: 05/27/1992
• Status: Expired due to Term

• Current Assignee: Opnext Japan, Inc. (Oclaro (Canada), Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Takeda, Junji, Irie, Hiroki, Azumaguchi, Teruhisa, Kohno, Tsutomu, Takeuchi, Tamio, Ishizuka, Kohei, Miura, Atushi, Nakata, Masaya, Moriguchi, Akisada
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): BACARES, RAFAEL D
• Application Number:
  US08/027,988
• Time in Patent Office: 1,023 Days
• Field of Search: 359/110, 359/152, 359/154, 359/162, 359/163, 385/24, 385/92, 385/94
• US Class Current: 398/164
• CPC Class Codes: H04B 10/0775 Performance monitoring and measurement of transmission parameters
• CPC Class Codes: H04B 10/6911 Photodiode bias control, e.g. for compensating temperature variations

Abstract

A light transmission module is disclosed, having a light receiving element module, in which a photodiode and a coupling portion between the photodiode and a first optical fiber are hermetically sealed, and a light emitting element module, in which a laser diode driven by an electric signal and a coupling portion between said laser diode and a second optical fiber are also hermetically sealed. A two-sided print board is provided, on the two sides of which electric circuits for a transmitting system and a receiving system are mounted. The electric circuits for the transmitting and receiving circuits are; isolated electrically from each other, and are sealed in one body by molds, and accommodated in cases, together with the light receiving element module and the light emitting element module.

Claims

1. A light transmission module comprising:

a first optical fiber for receiving a first optical signal from the exterior of the light transmission module;

a second optical fiber for transmitting a second optical signal to the exterior;

an opto-electric converting element connected with said first optical fiber for converting said first optical signal into a received electric signal;

a light receiving element module for accommodating said opto-electric converting element and sealing hermetically a connecting portion between said opto-electric converting element and said first optical fiber;

a receiving circuit for reproducing received data from said received electric signal and for outputting said reproduced received data;

a transmitting circuit for converting data to be transmitted into an electric signal to be transmitted;

a light emitting element connected with said second optical fiber and driven by said transmitting circuit for converting said electric signal to be transmitted into said second optical signal;

a light emitting element module for accommodating said light emitting element and sealing hermetically a connecting portion between said light emitting element and said second optical fiber;

a circuit print board, on which said receiving circuit and said transmitting circuit are mounted, isolated electrically from each other; and

a mold for sealing said light receiving element module, said light emitting element module and said circuit print board in one body, wherein said receiving circuit comprises;

an amplifying circuit IC for amplifying said received electric signal to output an amplified electric signal;

a surface acoustic wave filter for extracting a clock component from said amplified electric signal outputted by said amplifying circuit IC; and

an identifying and reproducing circuit IC for converting said amplified electric signal outputted from said amplifying circuit IC into said received data with a timing of said clock component extracted by said surface acoustic wave filter.

9. A light transmission module according to claim 1, wherein said mold is comprised of resin.

2. A light transmission module converting an optical signal received from a receiving optical fiber into a received electric signal to output it and converting an inputted electric signal to be transmitted into an optical signal to output it to a transmitting optical fiber, comprising:

(a) a light receiving element module, in which a photodiode and a coupling portion between said photodiode and said receiving optical fiber are hermetically sealed;

(b) a light emitting element module, in which a laser diode driven by an electric signal and a coupling portion between said laser diode and said transmitting optical fiber are hermetically sealed;

(c) a two-sided print board, on the two sides of which are mounted a transmitting circuit IC driving said laser diode, responding to a value of inputted data from said inputted electric signal to be transmitted, an amplifying circuit IC amplifying the received electric signal obtained by conversion by means of said photodiode to output an amplified electric signal, a surface acoustic wave filter chip for extracting a clock component from said amplified electric signal outputted by said amplifying circuit IC, and an identifying and reproducing circuit IC for identifying an electric signal obtained by conversion by means of said photodiode with a timing of said clock component extracted by said surface acoustic wave filter chip to reproduce and output received data; and

(d) a mold sealing said light receiving element module, said light emitting element module, and said two-sided print board in one body.

5. A light transmission module according to claim 2, wherein said mold is comprised of resin.

3. A light transmission module converting an optical signal received from a receiving optical fiber into a received electric signal to output it and converting an inputted electric signal to be transmitted into an optical signal to output it to a transmitting optical fiber, comprising:

(a) a light receiving element module, in which an avalanche photodiode converting an inputted optical signal into an electric signal, depending on a voltage applied thereto, and a coupling portion between said avalanche photodiode and said receiving optical fiber are hermetically sealed;

(b) a light emitting element module, in which a laser diode driven by an electric signal and a coupling portion between said laser diode and said transmitting optical fiber are hermetically sealed;

(c) a two-sided print board, on the two sides of which are mounted a transmitting circuit IC driving said laser diode, responding to a value of inputted data from said inputted electric signal to be transmitted, an amplifying circuit IC amplifying the received electric signal obtained by conversion by means of said avalanche photodiode to output an amplified electric signal, a surface acoustic wave filter chip for extracting a clock component from said amplified electric signal outputted by said amplifying circuit IC, and an identifying and reproducing circuit IC for identifying an electric signal obtained by conversion by means of said avalanche photodiode with a timing of said clock component extracted by said surface acoustic wave filter chip to reproduce and output received data, and an avalanche photodiode control circuit controlling a voltage applied to said avalanche photodiode, responding to the amplified electric signal outputted by said amplifying circuit; and

(d) a mold sealing said light receiving element module, said light emitting element module, and said two-sided print board in one body.

6. A light transmission module according to claim 3, wherein said mold is comprised of resin.

4. A light transmission module converting an optical signal received from a receiving optical fiber into a received electric signal to output it and converting an inputted electric signal to be transmitted into an optical signal to output it to a transmitting optical fiber, comprising:

(a) a light receiving element module, in which an opto-electrical converting element and a coupling portion between said opto-electrical converting element and said receiving optical fiber are hermetically sealed;

(b) a light emitting element module, in which a light emitting element driven by an electric signal and a coupling portion between said light emitting element and said transmitting Optical fiber are hermetically sealed;

(c) a two-sided print board, on the two sides of which are mounted a transmitting circuit driving said light emitting element, responding to a value of inputted data from said inputted electric signal to be transmitted, and a receiving circuit reproducing and outputting received data from the received electric signal obtained by conversion by means of said opto-electric converting element, wherein said transmitting circuit and said receiving circuit are electrically isolated from each other on said two-side print board; and

(d) a mold sealing said light receiving element module, said light emitting element module, and said two-sided print board in one body;

wherein said mold is comprised of resin.

7. A light transmission module comprising:

a first optical fiber for receiving a first optical signal from the exterior of the light transmission module;

a second optical fiber for transmitting a second optical signal to the exterior;

an opto-electric converting element connected with said first optical fiber for converting said first optical signal into a received electric signal;

a receiving circuit for reproducing received data from said received electric signal and for outputting said reproduced received data;

a transmitting circuit for converting data to be transmitted into an electric signal to be transmitted;

a light emitting element connected with said second optical fiber and driven by said transmitting circuit for converting said electric signal to be transmitted into said second optical signal;

a circuit print board, on which said receiving circuit and said transmitting circuit are mounted; and

means for decreasing cross-talk between said receiving circuit and said transmitting circuit, said means comprising said light receiving element module including means for hermetically sealing a connecting portion between said opto-electric converting element and said first optical fiber, said light emitting element module including means for hermetically sealing a connecting portion between said light emitting element and said second optical fiber, said circuit print board including means for electrically isolating said receiving circuit and said transmitting circuit from one another, and a mold for sealing said light receiving element module, said light emitting element module and said circuit board in one body, wherein said receiving circuit comprises;

an amplifying circuit IC for amplifying said received electric signal to output an amplified electric signal;

a surface acoustic wave filter for extracting a clock component from said amplified electric signal outputted by said amplifying circuit IC; and

an identifying and reproducing circuit IC for converting said amplified electric signal outputted from said amplifying circuit IC into said received data with a timing of said clock component extracted by said surface acoustic wave filter.

10. A light transmission module according to claim 7, wherein said mold is made of resin including glass fiber.

8. A light transmission module comprising:

a first optical fiber for receiving a first optical signal from the exterior of the light transmission module;

a second optical fiber for transmitting a second optical signal to the exterior;

an opto-electric converting element connected with said first optical fiber for converting said first optical signal into a received electric signal;

a receiving circuit for reproducing received data from said received electric signal and for outputting said reproduced received data;

a transmitting circuit for converting data to be transmitted into an electric signal to be transmitted;

a light emitting element connected with said second optical fiber and driven by said transmitting circuit for converting said electric signal to be transmitted into said second optical signal;

a circuit print board, on which said receiving circuit and said transmitting circuit are mounted; and

means for decreasing cross-talk between said receiving circuit and said transmitting circuit, said means comprising said light receiving element module including means for hermetically sealing a connecting portion between said opto-electric converting element and said first optical fiber, said light emitting element module including means for hermetically sealing a connecting portion between said light emitting element and said second optical fiber, said circuit print board including means for electrically isolating said receiving circuit and said transmitting circuit from one another, and a mold for sealing said light receiving element module, said light emitting element module and said circuit board in one body;

wherein said mold is made of resin including glass fiber.