New code for communications network fault finding using a spread spectrum approach

Abstract

This paper reports on the development of a new digital sequence allowing the use of a semiconductor laser amplifier (SLA) to execute signal correlation in the optical domain. The new sequence permits multiple reflections from components of a fibre optic communications network to be detected with zero crosstalk. This digital spread spectrum approach is demonstrated experimentally in a simple passive fibre optic network where Fresnel reflections from the fibre ends are detected.