Simultaneous monitoring of first-order polarization mode dispersion and chromatic dispersion based on RF power detection technique

We propose a novel technique for independent and simultaneous monitoring of first-order polarization mode dispersion (PMD) and chromatic dispersion (CD). For PMD monitoring, radio frequency (RF) power is detected after asymmetric filtering by a band-stop filter (BSF). The RF tone power ratio (PR) of the double sideband (DSB) to the single sideband (SSB) signal components is utilized for CD monitoring. We discuss the performance for 80 Gb/s NRZ-DQPSK signal by simulation. Simultaneous monitoring of 246.7 ps/nm CD with a 22.3 dB dynamic range (DR) and 50 ps differential group delay (DGD) with a 42.7 dB DR can be realized at 10 GHz detection band. When only CD is monitored, the detection frequency can be further decreased to 5 GHz, where the monitoring range (MR) is 356 ps/nm and DR is 30.5 dB. The influences of other parameters, such as the BSF offset, the bandwidths of BSF and electrical-band-pass-filter (EBPF), the filter shape, and the modulation rate and format, are investigated in the paper.