Passive all optical non-return-to-zero to pseudo-return-to-zero signal conversion for all optical clock recovery

In this paper we propose a simple clock signal extraction method from NRZ signal. The proposed passive all optical signal converter is constructed by using a simple asymmetric Mach-Zender interferometer. The signal converter is also applicable as a NRZ to PRZ converter in a conventional high bit rate optical receiver with an optical preamplifier.