Chromatic dispersion monitor method for signals with high duty cycles

This paper proposed a method which utilizes phase-matched FWM to effectively enhance the chromatic dispersion (CD) monitoring sensitivity and monitoring range of the signals with high duty cycles. The scheme was realized by inputting a signal and continuous probe wave simultaneously into high nonlinear fiber, and the generated idler wave, whose power carried the CD information, was followed by a filter and optical power meter. The numerical simulation showed clearly that through employing this method, the monitoring range for CSRZ and NRZ could be 8 and 6.2dB respectively. In this paper we also puted forward a peak search algorithm utilizing a TDC module to increase NRZ and CSRZ monitoring range to 800 ps/nm.