Optical source with frequency locked to an in-fiber grating resonator

摘要

A frequency stabilized optical signal source is provided. A laser (10) produces an optical carrier at a wavelength λ. Feedback is provided to adjust the wavelength λ. In order to provide the feedback, a portion of the optical carrier is modulated by a periodic reference signal (wrf). An optical fiber (16) with an in-fiber resonator (18) is coupled to receive the modulated optical carrier. The resonator effects a phase and/or amplitude change between the modulated optical carrier and a sideband thereof at a resonant frequency of the resonator. The phase or amplitude change is detected and used to adjust the laser wavelength. In a preferred embodiment, a moire grating having a single resonant frequency is used as the in-fiber resonator. The feedback scheme can lock either to the carrier frequency itself, or to a selected sideband of the modulated optical carrier.