Dynamic dispersion detecting method and apparatus

A dynamic dispersion detecting apparatus, comprising a tunable dispersion compensation module, a demodulator, a receiver, a partial band radio frequency power detecting unit, and an electrical signal ratio calculating unit, wherein:

• the tunable dispersion compensation module is configured to send a received optical signal to the demodulator after compensating for a dispersion of the optical signal;
• the demodulator is configured to demodulate a phase of the received optical signal;
• the receiver is configured to convert the optical signal outputted by the demodulator into an electrical signal;
• the partial band radio frequency power detecting unit is configured to sample radio frequency power of the electrical signal converted by the receiver to obtain a radio frequency signal;
• the electrical signal ratio calculating unit is configured to obtain an electrical signal ratio of the radio frequency signal and send the electrical signal ratio to the tunable dispersion compensation module continuously;
• and
• the tunable dispersion compensation module is configured to compare a value of the currently received electrical signal ratio and the values of the previously received electrical signal ratios, tune a dispersion compensation value according to a comparison result to obtain a peak electrical signal ratio, and determine a residual dispersion value of a system according to the peak electrical signal ratio.