Optical Reception Device

An optical reception device, comprising:

• a Mach-Zehnder type 1-bit delay unit having one or a plurality of phase control functions of controlling a phase state of light;
• a balanced receiver for differentially receiving an optical output signal output from one or the other output port of the Mach-Zehnder type 1-bit delay unit;
• and
• a phase control unit for controlling a phase state of the Mach-Zehnder type 1-bit delay unit based on an output of the balanced receiver,
• wherein the phase control unit comprises:
• dither signal generation means for generating a dither signal;
• a low-pass filter for passing a low-frequency component of a branched output that is output from the balanced receiver;
• phase comparison means for outputting as an error signal a phase comparison signal that represents a phase comparison result between the dither signal and an output signal of the low-pass filter;
• a phase control circuit for generating a phase control signal for controlling the Mach-Zehnder type 1-bit delay unit based on the error signal output from the phase comparison means;
• and
• an adder for adding the dither signal to the phase control signal output from the phase control circuit, and
• wherein the phase control unit controls a phase state of the Mach-Zehnder type 1-bit delay unit based on an output signal from the adder.

An optical reception device, comprising:

• a Mach-Zehnder type 1-bit delay unit having one or a plurality of phase control functions of controlling a phase state of light;
• photoelectric conversion means for branching a part of an optical output signal output from a one-side output port of the Mach-Zehnder type 1-bit delay unit and converting it into an electric signal;
• a phase control unit for controlling a phase state of the Mach-Zehnder type 1-bit delay unit by using as an error signal an output signal of the photoelectric conversion means;
• a balanced receiver for differentially receiving an optical output signal output from one or the other output port of the Mach-Zehnder type 1-bit delay unit;
• error detection means for generating an error signal based on error correction information obtained when identification reproduction processing and error correction processing are performed with respect to a differential output of the balanced receiver;
• and
• a second phase control circuit for generating a second phase control signal for controlling the Mach-Zehnder type 1-bit delay unit based on an output of the error detection means,
• wherein the phase control unit comprises:
• dither signal generation means for generating a dither signal;
• a low-pass filter for passing a low-frequency component of an electric signal output from the photoelectric conversion means;
• phase comparison means for outputting as an error signal a phase comparison signal that represents a phase comparison result between the dither signal and an output signal of the low-pass filter;
• a first phase control circuit for generating a first phase control signal for controlling the Mach-Zehnder type 1-bit delay unit based on the error signal output from the phase comparison means;
• and
• an adder for adding the dither signal to the first phase control signal output from the first phase control circuit,
• wherein the phase control unit controls a phase state of the Mach-Zehnder type 1-bit delay unit based on an output signal from the adder, and
• wherein the second phase control circuit controls a phase state of the Mach-Zehnder type 1-bit delay unit based on the second phase control signal.