Signal quality monitoring for optical communications networks

Abstract

The subject of this thesis is optical performance monitoring for transparent optical communications networks. To this end, a series of techniques for the characterisation of ultrashort telecommunications pulses were developed. Two phase-sensitive pulse monitoring techniques were employed to fully recover the electric field of 2ps pulses (i.e. the phase and spectrum) generated using a modelocked laser with varying levels of chirp. Both schemes involved the use of sinusoidal optical phase modulation followed by harmonic decomposition of the measured spectrum, which had been modified by the phase modulation. The scheme was validated through comparison with a standard SHGFROG system and compared by way of simulation with Kang and Dorrer's sinusoidal phase modulation scheme.