OPTICAL-FIBER VIBRATION SENSOR USING (PANCHARATNAM) PHASE STEP INTERFEROMETRY

A fiber-optic vibration sensor based on polarization- and phase-step i nterferometry is reported, Left- and right-circularly polarized light coming back from the reference and signal arms of a modified Michelson fiber interferometer is processed with an array of five linear analyz ers separated angular steps of pi/4 (rad) from each other, Thus, five interference patterns are acquired simultaneously and the dynamical ph ase retrieval problem is reduced to five-step interferometry in the ti me-domain, A vibration sensor as described above was built by the auth ors and its performance was investigated.