Abstract

Summary: Phase modulators are used in many interferometric sensors, to aid signal processing and remove signal fading [1]. Typically, a length of fibre is attached to a piezoelectric material, such as a PZT tube/plate of PVdF film, which under electrical modulation produces length and refractive index variations in the fibre [2]. In this configuration the performance of the optical fibre phase modulator is exclusively determined by the mechanical characteristics of the piezoelectric material, limiting performance and reducing modulator flexibility. Operation at the resonance frequency of the piezoelectric transducer optimises the phase modulation efficiency. However, modulation at resonance can produce polarization modulation, high temperature susceptibility and subharmonic or chaotic modulation [3].

© 1988 Optical Society of America