Compensated polarimetric sensor using polarisation-maintaining fibre in a differential configuration

The letter describes a novel configuration of the polarimetric sensor which uses two equal lengths of polarisation-maintaining fibre spliced together with their major polarisation axes orthogonal. The result is a differential sensor which is compensated for common-mode temperature and isotropic pressure changes, and may be used with semiconductor laser sources without the problems of phase noise which can arise in the normal polarimetric sensor.