HIGH-PERFORMANCE HETERODYNE OPTICAL-INJECTION PHASE-LOCK LOOP USING WIDE LINEWIDTH SEMICONDUCTOR-LASERS

The requirements for narrow linewidth lasers or short-loop propagation delay limit optical phase-lock loop realizability with semiconductor lasers, Although optical injection locking can provide low-phase-error variance, its locking range is limited by stability considerations, T he first experimental results for an heterodyne optical injection phas e-lock loop are reported, Phase-error variance as low as 0.003 rad(2) in a bandwidth of 100 MHz, single-sideband (SSB) noise density of -94 dBc/Hz at 10-kHz offset and mean time to cycle slip of 3 x 10(10) s ha ve been achieved using DFB lasers of 36-MHz summed linewidth, a loop p ropagation delay of 20 ns and an injection ratio of -30 dB.