Optical receiver and light receiving method

• US 8,326,145 B2
• Filed: 10/08/2009
• Issued: 12/04/2012
• Est. Priority Date: 10/09/2008
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Takahara, Tomoo
• Primary Examiner(s): Singh, Dalzid
• Application Number:
  US12/575,810
• Publication Number:
  US 20100092186A1
• Time in Patent Office: 1,153 Days
• Field of Search: 398/33, 398202-204, 398208-210
• US Class Current: 398/33
• CPC Class Codes: H04B 10/695 Arrangements for optimizing the decision element in the receiver, e.g. by using automatic threshold control

Abstract

An apparatus and method includes converting an optical signal that is received into an electrical signal and outputting the electrical signal, converting the electrical signal into a data signal and outputting the data signal by comparing the electrical signal with a reference voltage, monitoring the electrical signal and output monitored information, and controlling the reference voltage based on the monitored information.

Claims

1. An apparatus, comprising:

a first converter configured to convert an optical signal that is received into an electrical signal and output the electrical signal;

a second converter configured to convert the electrical signal into a digital data signal and output the digital data signal by comparing the electrical signal with a plurality of reference voltages;

a monitor configured to monitor the electrical signal and output monitored information; and

a controller configured to control the plurality of reference voltages based on a value indicated by the monitored information.

2. The apparatus according to claim 1, wherein the monitor monitors a current value of the electrical signal and outputs information about the current value as the monitored information.

3. The apparatus according to claim 2, wherein the first converter includes a photodiode and a resistor provided between the photodiode and a bias voltage, and

wherein the monitor monitors a current value flowing through the resistor and outputs information about the current value as the monitored information.

4. The apparatus according to claim 2, wherein the first converter includes an output terminal for the electrical signal, a load resistor connected to the output terminal, and a shunt resistor connected to the load resistor, and

wherein the monitor monitors a current value flowing through the shunt resistor and outputs information about the current value as the monitored information.

5. The apparatus according to claim 1, wherein the monitor monitors a power of the electrical signal and outputs information about the power as the monitored information.

6. The apparatus according to claim 1, wherein the monitor monitors a peak value of the electrical signal and outputs information about the peak value as the monitored information.

7. The apparatus according to claim 1, wherein the monitor monitors an amplitude of the electrical signal and outputs information about the amplitude as the monitored information.

8. The apparatus according to claim 1, wherein the second converter includes:

a first analog-to-digital converter that compares the electrical signal with a reference voltage in synchronization with a clock signal to output a first data signal, and

a second analog-to-digital converter that compares the electrical signal with a reference voltage in synchronization with an inverted clock signal to output a second data signal.

9. A signal generating circuit, comprising:

a first converter configured to convert an optical signal that is received into an electrical signal and output the electrical signal;

a second converter configured to convert the electrical signal into a digital data signal and outputs the digital data signal by comparing the electrical signal with a plurality of reference voltages;

a monitor configured to monitor the electrical signal and output monitored information; and

a controller configured to control the plurality of reference voltages based on a value indicated by the monitored information.

10. A receiving method for an apparatus, the method comprising:

receiving an optical signal;

converting the optical signal into an electrical signal;

monitoring the electrical signal to acquire monitored information;

controlling a plurality of reference voltages based on a value indicated by the monitored information; and

converting the electrical signal into a digital data signal by comparing the electrical signal with the controlled plurality of reference voltages.

11. A method of controlling a circuit, comprising:

outputting monitored information and inputting an electrical signal to be monitored by a monitor;

converting the electrical signal into a digital data signal;

outputting the digital data signal by comparing the electrical signal with a plurality of reference voltages; and

controlling a plurality of reference voltages in accordance with a value indicated by the monitored information.