DIODE-LASERS LOCKED TO NOISY INJECTION

We have analyzed the behavior of a diode laser with low-amplitude opti cal injection, The noisy injection field has phase fluctuations only, with a linewidth larger than both the free-running stave laser linewid th and the locking range, Simulations show that the laser output spect rum can be much narrower than the injection spectrum and may have a di p at the free-running laser frequency, A model describing these featur es is based on linear superposition of the stationary responses to mon ochromatic injection, The mechanism of line narrowing is that the resp onse to injection outside the locking range lies mainly inside.