An asymptotically optimal receiver for heterodyne optical communication

Assuming phase coherence at the beginning of each transmitted sequence, a heterodyne optical channel incoherent receiver is derived which is optimal in the limit of small bit intervals with respect to the coherence time of the laser oscillations. It is shown that the receiver reduces to the channel model of Jeromin and Chan (1983) when no initial phase coherence is present. For the coherence times of existing lasers and the data rates envisioned for some intersatellite link applications, the small performance improvement obtained in the computer simulations by resolving an initial phase uncertainty may not justify the extra complexity needed.