On-chip high sensitivity laser frequency sensing with Brillouin mutually-modulated cross-gain modulation

We report the first demonstration of a photonic-chip laser frequency sensor using Brillouin mutually-modulated cross-gain modulation (MMXGM). A large sensitivity (∼9.5 mrad/kHz) of the modulation phase shift to probe carrier frequency is demonstrated at a modulation frequency of 50 kHz using Brillouin MMXGM in a ∼7 cm long chalcogenide rib waveguide. © 2013 Optical Society of America.