Patent ID: 11888528
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An optical communication system comprising:
transmitter configured to output a signal light having two subcarriers that are generated from a single carrier light and are modulated using data in a phase-conjugate relationship; and
a receiver including
a light phase synchronization mechanism configured to generate a synchronized light that is phase-synchronized with the signal light transmitted from the transmitter, the light phase synchronization mechanism including a second-order nonlinear optical element configured to generate a sum frequency light of the two subcarriers of the transmitted signal light, a second-order nonlinear optical element configured to generate a second harmonic light of sideband light generated from a local oscillation light, and a feedback loop mechanism configured to compare frequencies and phases of the sum frequency light and the second harmonic light and synchronize the phases of the transmitted signal light and the sideband light, the light phase synchronization mechanism being configured to output the sideband light as the synchronization light,
a non-degenerate optical phase-sensitive amplifier configured to use the synchronized light to amplify the transmitted signal light, and
a coherent receiver configured to use the synchronized light to demodulate the amplified signal light.