Optical receiver module

Abstract

A semiconductor chip on which a light receiving element is mounted, a preamplifier for amplifying an output signal from the light receiving element, and an insulating carrier substrate on which the light receiving element is mounted are connected such that the output signal from the light receiving element is input to the preamplifier through electrodes on the carrier substrate, and there are provided two electrodes, on the carrier substrate, having a capacitance value of 40 fF or more therebetween in a state where no light receiving element is mounted.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of a high-frequency equivalent circuit from a photodiode to an input portion of a preamplifier;

FIG. 2 is a plan view depicting main parts of an optical receiver module;

FIGS. 3A and 3B are partially perspective plan views of a carrier substrate part;

FIG. 4 is a perspective sectional view of the carrier substrate;

FIG. 5 is a diagram of a high-frequency equivalent circuit from a photodiode to an input portion of a preamplifier;

FIG. 6 is a graph showing a relation between input impedance and capacitance value;

FIGS. 7A and 7B show frequency characteristics of the optical receiver module to explain effects;

FIG. 8 is a plan view depicting main parts of an optical receiver module; and

FIGS. 9A and 9B are partially perspective plan views of a carrier substrate part.

Claims

1. An optical receiver module comprising: a light receiving element for converting an optical signal with a bit rate of approximately 10 Gbits/s into an electrical signal; anda preamplifier for amplifying said electrical signal,wherein said light receiving element is mounted on two electrodes for said mounting light receiving element of a carrier substrate, and the capacitance value between the two electrodes is 40 fF or more.

2. An optical receiver module comprising: a light receiving element for converting an optical signal with a bit rate of approximately 10 Gbits/s into an electrical signal;a carrier substrate on which said light receiving element is mounted; anda preamplifier for amplifying said electrical signal,wherein the capacitance value between two electrodes of said carrier substrate is 40% or more of the capacitance value between two electrodes of said light receiving element.

3. An optical receiver module comprising: a light receiving element for converting an optical signal with a bit rate of approximately 10 Gbits/s into an electrical signal;a carrier substrate on which said light receiving element is mounted; anda preamplifier for amplifying said electrical signal,wherein a first light receiving element mounting-position and a second light receiving element mounting-position are provided on said carrier substrate.

4. The optical receiver module according to claim 1, wherein the capacitance value between the two electrodes of said light receiving element is 100 fF or less.

5. The optical receiver module according to claim 2, wherein the capacitance value between the two electrodes of said light receiving element is 100 fF or less.

6. The optical receiver module according to claim 3, wherein the capacitance value between the two electrodes of said light receiving element is 100 fF or less.

7. The optical receiver module according to claim 3, wherein the capacitance value between two electrodes on said first light receiving element mounting-position is 40 fF or more, andthe capacitance value between two electrodes on said second light receiving element mounting-position is less than 40 fF.

8. The optical receiver module according to claim 7, wherein the capacitance value between the two electrodes on said second light receiving element mounting-position is less than 10 fF.

9. The optical receiver module according to claim 1, wherein the input impedance of said preamplifier is 30Ω or less.

10. The optical receiver module according to claim 2, wherein the input impedance of said preamplifier is 30Ω or less.

11. The optical receiver module according to claim 3, wherein the input impedance of said preamplifier is 30Ω or less.

12. The optical receiver module according to claim 1, wherein the power voltage of said preamplifier is 3.3V or less.

13. The optical receiver module according to claim 2, wherein the power voltage of said preamplifier is 3.3V or less.

14. The optical receiver module according to claim 3, wherein the power voltage of said preamplifier is 3.3V or less.

15. The optical receiver module according to claim 1, wherein said light receiving element is of a back surface incidence-type in which said light receiving element is mounted on said carrier substrate by face down mounting.

16. The optical receiver module according to claim 2, wherein said light receiving element is of a back surface incidence-type in which said light receiving element is mounted on said carrier substrate by face down mounting.

17. The optical receiver module according to claim 3, wherein said light receiving element is of a back surface incidence-type in which said light receiving element is mounted on said carrier substrate by face down mounting.

18. The optical receiver module according to claim 1, wherein said carrier substrate and said preamplifier are provided on a metal stem in a CAN-type case.

19. The optical receiver module according to claim 2, wherein said carrier substrate and said preamplifier are provided on a metal stem in a CAN-type case.

20. The optical receiver module according to claim 3, wherein said carrier substrate and said preamplifier are provided on a metal stem in a CAN-type case.