A novel optical transmission method using an inline phase modulator

Abstract

This thesis presents a novel optical communication technique that provides a second, low data rate channel on an existing high-speed fiber optic link. The second channel is derived using an acousto optic fiber phase modulator and interferometeric receiver. This method modulates the optical phase of the primary high speed optical signal with a low frequency sine wave. At the receiving end of the low speed path, an interferometer and band pass fiber are used to recover the low-speed signal. Information is carried on the low frequency sine wave by use of FSK modulation. The method is noninvasive in that the low-speed channel is derived without electrically, optically or physically affecting the performance of the high-speed optical path. The method is ideal for overlaying network management channels on a fiber network. The thesis includes both analysis and experimental verification of the technique.