Measurement method and apparatus for residual direct-current components and a system

A measurement apparatus for residual direct-current components, applicable to a dual-polarization optical communication system, the measurement apparatus comprising:

• a memory that stores a plurality of instructions;
• and
• a processor coupled to the memory and configured to execute the instructions to:
• measure a sum of power of residual direct-current components in two polarization states;
• measure a difference between the power of the residual direct-current components in the two polarization states;
• and
• calculate power of a residual direct-current component in each polarization state of an optical transmitter according to the measured sum of power and the measured difference between the power;
• and wherein, the processor is configured to execute the instructions to:
• select a section of data of a first predetermined length respectively from received signals in the two polarization states;
• perform a coordinate transform on two selected sections of data to obtain a group of vectors of Strokes space;
• and
• determine the difference between power of the residual direct-current components according to the group of vectors of Strokes space,
• wherein, performance of the dual-polarization optical communication system is diagnosed or improved in accordance with the calculated power of the residual direct-current component in each polarization state of the optical transmitter.

A measurement apparatus for residual direct-current components, applicable to a dual-polarization optical communication system, the measurement apparatus comprising:

• a memory that stores a plurality of instructions;
• and
• a processor coupled to the memory and configured to execute the instructions to:
• select a section of data of a first predetermined length respectively from received signals in two polarization states;
• perform coordinate transform on two selected sections of data to obtain a group of vectors of Strokes space;
• and
• determine a difference between power of the residual direct-current components according to the group of vectors of the Strokes space,
• wherein, performance of the dual-polarization optical communication system is diagnosed or improved in accordance with the determined difference between power of the residual direct-current components.

A measurement method for residual direct-current components, applicable to a dual-polarization optical communication system, the measurement method comprising:

• selecting a section of data of a first predetermined length respectively from received signals in two polarization states;
• performing a coordinate transform on two selected sections of data to obtain a group of vectors of Strokes space;
• and
• determining a difference between power of the residual direct-current components according to the group of vectors of the Strokes space,
• wherein, performance of the dual-polarization optical communication system is diagnosed or improved in accordance with the determined difference between power of the residual direct-current components.