Optical receiver for regeneration of optical signal

• US 7,809,286 B2
• Filed: 06/01/2009
• Issued: 10/05/2010
• Est. Priority Date: 10/11/2005
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yamabana, Tetsuji, Ide, Satoshi
• Primary Examiner(s): Liu; Li
• Application Number:
  US12/475,833
• Publication Number:
  US 20090232519A1
• Time in Patent Office: 491 Days
• Field of Search: 398/137, 398/202, 398208-214, 330/308, 330/72, 330/136
• US Class Current: 398/209
• CPC Class Codes: H04B 10/66 Non-coherent receivers, e.g. using direct detection

Abstract

An optical receiver includes: a converting unit that converts an optical signal into an electrical signal; an amplifying unit that amplifies the electrical signal; a regenerating unit that regenerates the amplified electrical signal; a correcting unit that performs correction of an error included in the regenerated electrical signal; a monitoring unit that performs monitoring of an optical current flowing through the converting unit; and a control unit that calculates a decision threshold based on a result of the correction and a result of the monitoring.

Claims

1. An optical receiver comprising:

a converter that converts an optical signal into an electrical signal;

an amplifier that amplifies the electrical signal;

a regenerator that regenerates the electrical signal amplified by the amplifier;

a corrector that performs correction of an error included in the electrical signal regenerated by the regenerator;

a monitor that performs monitoring of an optical current flowing through the converter;

a controller that calculates a decision threshold based on a result of the correction and a result of the monitoring; and

a feedback amplifier that controls a direct current level of a signal output from the amplifier by branching a part of the signal to be fed back to the amplifier,

wherein the decision threshold is input to the feedback amplifier.

2. The optical receiver according to claim 1, wherein

the amplifier is a limiting amplifier that linearly amplifies the electrical signal when the power thereof is less than a given value (linear operation), and otherwise limits the electrical signal (limiting operation), and

the decision threshold changes according to the power of the electrical signal up to a value unique to each threshold during the linear operation, and remains constant thereafter during the limiting operation.