Theory of FM clicks with Brownian motion phase noise

Lasers that are used for coherent optical communication exhibit phase instabilities which can be modeled as a Brownian motion. The effect that such a disturbance has on limiter-discriminator detection of FM signals received in additive Gaussian noise is investigated. Although a new theory must be developed to calculate FM click rates (and prove them finite), no effects are found which would preclude the use of such a detector with Brownian phase noise. In particular, for binary FM transmission at rate R, discriminator detection will result in 1 dB of degradation or less if B_pn/R<0.002, B_pn being the linewidth of the unmodulated carrier