Optical transmission system, phase conjugate converter and phase sensitive amplifier

A phase conjugate conversion device comprising:

• a first splitter configured to split pump light;
• a multiplexer configured to multiplex first pilot light that is generated on a basis of the pump light split by the first splitter and propagates in a first direction, and an optical signal transmitted from an optical transmitter;
• a second splitter configured to split the pump light split by the first splitter;
• a plurality of transferers that respectively performs phase control on a plurality of pieces of the pump light split;
• a plurality of harmonic generators configured to convert the plurality of pieces of the pump light subjected to phase control by the respective plurality of transferers into harmonics;
• a divider configured to divide the first pilot light and the optical signal that are multiplexed by the multiplexer into two polarization components orthogonal to each other;
• a first optical parametric amplifier configured to perform optical parametric amplification on a basis of a first polarization component of the first pilot light and a first polarization component of the optical signal that are divided by the divider, and the harmonics converted by the plurality of harmonic generators;
• a second optical parametric amplifier configured to perform optical parametric amplification on a basis of a second polarization component of the first pilot light and a second polarization component of the optical signal that are divided by the divider, and the harmonics converted by the plurality of harmonic generators;
• a combiner configured to generate an optical transmission signal by multiplexing the first polarization component of the first pilot light and the first polarization component of the optical signal that are amplified by the first optical parametric amplifier, and the second polarization component of the first pilot light and the second polarization component of the optical signal that are amplified by the second optical parametric amplifier;
• a first monitor configured to monitor power of the first polarization component of the first pilot light amplified by the first optical parametric amplifier;
• a second monitor configured to monitor power of the second polarization component of the first pilot light amplified by the second optical parametric amplifier;
• a first controller configured to synchronize phases of the harmonics and the first pilot light by controlling phases of the pump light input to the plurality of harmonic generators to cause each of optical power of the first pilot light amplified by the first optical parametric amplifier and optical power of the first pilot light amplified by the second optical parametric amplifier to be maximum on a basis of monitoring results by the first monitor and the second monitor;
• a second pilot light source configured to output second pilot light in which at least a wavelength or optical power is different from that of the first pilot light;
• a circulator configured to propagate the second pilot light output from the second pilot light source in a second direction that is an opposite direction to the first direction, and externally outputs the optical transmission signal output from the combiner;
• and
• a second controller configured to match optical lengths of paths of the first optical parametric amplifier and the second optical parametric amplifier by controlling a transfer device arranged in at least one of the paths to cause an interference waveform of components of the second pilot light caused to pass in the second direction through each of the first optical parametric amplifier and the second optical parametric amplifier to be maximum.

A phase-sensitive amplification device comprising:

• a pump light source configured to output pump light for optical parametric amplification by performing optical injection locking to the pump light source by using first pilot light included in an optical transmission signal transmitted from a phase conjugate conversion device configured to perform optical parametric amplification;
• a third splitter configured to split the pump light output from the pump light source;
• a plurality of transferers configured to respectively perform phase control on a plurality of pieces of the pump light split;
• a plurality of harmonic generators configured to convert the plurality of pieces of the pump light subjected to phase control by the respective plurality of transferers into harmonics;
• a divider configured to divide an optical signal included in the optical transmission signal into two polarization components orthogonal to each other;
• a third optical parametric amplifier configured to perform optical parametric amplification on a basis of a first polarization component of the optical signal divided by the divider and the harmonics converted by the plurality of harmonic generators;
• a fourth optical parametric amplifier configured to perform optical parametric amplification on a basis of a second polarization component of the optical signal divided by the divider and the harmonics converted by the plurality of harmonic generators;
• a combiner configured to multiplex the first polarization component of the optical signal amplified by the third optical parametric amplifier and the second polarization component of the optical signal amplified by the fourth optical parametric amplifier;
• a third monitor configured to monitor power of the first polarization component of the optical signal amplified by the third optical parametric amplifier;
• a fourth monitor configured to monitor power of the second polarization component of the optical signal amplified by the fourth optical parametric amplifier;
• a third controller configured to synchronize phases of the harmonics and the optical signal by controlling phases of the pump light input to the plurality of harmonic generators to cause each of optical power of the optical signal amplified by the third optical parametric amplifier and optical power of the optical signal amplified by the fourth optical parametric amplifier to be maximum on a basis of monitoring results by the third monitor and the fourth monitor;
• a third pilot light source configured to output third pilot light in which at least a wavelength or optical power is different from that of the first pilot light;
• a circulator configured to propagate the third pilot light output from the third pilot light source in a second direction that is an opposite direction to the first direction;
• and
• a fourth controller configured to match optical lengths of paths of the third optical parametric amplifier and the fourth optical parametric amplifier by controlling a transfer device arranged in at least one of the paths to cause an interference waveform of components of the third pilot light caused to pass in the second direction through each of the third optical parametric amplifier and the fourth optical parametric amplifier to be maximum.