Suppression of spontaneous modulation instability and phase noise with a coherent seed in the interferometric fiber sensing systems

A method is proposed to suppress spontaneous modulation instability (MI) and phase noise with a coherent seed in the interferometric fiber sensing systems. By generating coherent seeds with phase modulation, induced MI is excited in an optical fiber. The preferential gain of the coherent seeds compared to the amplified spontaneous emission noise suppresses spontaneous MI. As a result, the induced MI dominates in the optical fiber. The coherence of the output light is enhanced, and the phase noise is suppressed significantly. The maximum input power can be increased significantly, and the sensing range can be extended.