Low coherence technique to characterise reflectivityand timedelay as a function of wavelength within a long fibre grating

Abstract

A new technique for obtaining both time delay and reflectivity as a function of wavelength within a long fibre Bragg grating is presented. A narrowband wavelength-tunable reflector with a 0.18 nm bandwidth is used to select the interrogation wavelength, while optical coherence-domain reflectometry is used to obtain the time delay with better than 2 ps accuracy.