Coherent optical receiver and control method thereof

A control method of a coherent optical receiver, comprising the steps of:

• inputting a first polarization multiplexed optical signal obtained by multiplexing two polarization lights orthogonal to each other modulated by same initial signal respectively;
• separating the first polarization multiplexed optical signal into a first received polarization optical signal and a second received polarization optical signal;
• calculating a phase deviation value using a result from summing each squared value of a first digital received signal and a second digital received signal respectively obtained by coherent detection;
• performing a phase compensation processing using the phase deviation value as an initial value;
• and
• starting up a polarization de-multiplexing processing.

A control method of a coherent optical receiver, comprising the steps of:

• inputting a first polarization multiplexed optical signal obtained by multiplexing two polarization lights orthogonal to each other modulated by same initial signal respectively;
• separating the first polarization multiplexed optical signal into a first received polarization optical signal and a second received polarization optical signal;
• making a first received polarization optical signal and a second received polarization optical signal interfere with a local light respectively and detecting them;
• outputting a first digital received signal and a second digital received signal obtained by digitizing detected signals respectively;
• calculating a phase deviation value using a result from summing each squared value of the first digital received signal and the second digital received signal;
• and
• performing a phase compensation processing using the phase deviation value as an initial value.