Performance of Optical Fiber Based Phase Modulators and the Effects of Ambient Temperature

The optical fiber phase modulator is an important component in fiber opiie interferometers f sensors, where the modulation is achieved by physically varying the parameters such as the refractive index or the length of the optical fiber. The fiber optic phase modulator is normally realised by wrapping a fiber on piezo-electric transducer (PZT), usually of cylindrical form. It is difficult to rely purely on published data of piezoelectric constants, because the performance depends critically on the dimensions of the cylinder and the type and compositions of the PZT material. Hence, it is essential that the phase modulator is calibrated before being put to an application. The paper contains description of existing theories of phase modulation, comparison of experimental results with theoretical predictions, and phase dependance on ambient temperature