A transceiver, wherein the transceiver comprises a laser, a second coupler, a first multiplexer, an optical transmitter, a second multiplexer, a polarization processing optical device and a coherent receiver, wherein:
- the laser is connected to the second coupler;
- two ports of the second coupler are respectively connected to the first multiplexer and the optical transmitter;
- the optical transmitter is connected to the second multiplexer;
- the first multiplexer is connected to the polarization processing optical device, wherein the first multiplexer is configured to receive a local oscillator light sent by a peer device and to send a part of a laser light emitted by the laser to the peer device, the polarization processing optical device is configured to process the local oscillator light output by the first multiplexer, and the second multiplexer is connected to the coherent receiver, wherein the second multiplexer is configured to receive an optical signal sent by the peer device, and send an optical signal generated by the optical transmitter to the peer device;
- the coherent receiver is configured to receive processed local oscillator light obtained through the polarization processing optical device and the optical signal sent by the peer device;
- and
- the polarization processing optical device is connected to the coherent receiver, wherein the polarization processing optical device comprises a polarization beam splitter (PBS), a polarization rotator (PR), a first coupler, and a first phase tuner (PT), wherein:
- the PBS comprises three ports, one of the three ports of the PBS is connected to the first multiplexer, the other two of the three ports of the PBS are respectively connected to a first port of the PR and a first port of the first coupler, and the PR is configured to perform polarization rotation on an optical energy output by the PBS;
- a second port of the PR is connected to a second port of the first coupler;
- the first PT is disposed on a connection between the PBS and the first coupler, or the first PT is disposed on a connection between the PR and the first coupler;
- and
- a third port and a fourth port of the first coupler are configured to output single-polarization light in a same polarization state, and the first PT is configured to control an output optical power of the third port and an output optical power of the fourth port to be equal.