Limitation of rotation sensing by scattering

Abstract

There appear to be limitations in the operation of optical-fiber Sagnac gyro rotation sensors that have imposed a minimum measurable rotation rate that is much higher than that caused by quantum noise. We show that one source of limitation, namely, the superposition of a nonreciprocal pair of waves generated by backward scattering from the incident waves, can result in significant error but can be mitigated by appropriate system design and signal modulation.