100 MHZ-BANDWIDTH RESPONSE OF A FIBER PHASE MODULATOR WITH THIN PIEZOELECTRIC JACKET

100 MHz-bandwidth response of an all-fiber phase modulator composed of a single-mode optical fiber jacketed with a 10 mum-thick vinylidene f luoride/trifluoroethylene copolymer, radially poled is presented. Mult iple peaks of optical phase shifts induced are observed over the frequ ency range of 10-100 MHz and ascribed to radial resonances of a fiber- jacket composite. The theoretical analysis of phase shifts is performe d based on vibration theory of elasticity taking the exact geometry an d composition of the cylindrical multilayer structure into account. Th e analysis also shows that the phase modulation is strongly dependent on jacket thickness and the maximum induced phase shift will be obtain ed in the 100 MHz region when the jacket is chosen to be thin as 0.7 m um.