An Asymptotically Optimal Receiver for Heterodyne Optical Communication

An incoherent receiver is derived for the heterodyne optical channel under the assumption of Phase coherence at the start of each transmitted sequence. The receiver is optimal in the limit of small bit intervals with respect to the coherence time of the laser oscillators, and reduces to that proposed by Jeromin and Chan [1] when no initial phase coherence is present. Computer simulations indicate that the small amount of performance improvement obtained by resolving an initial phase uncertainty may not justify the extra complexity needed, for the data rates currently considered.