Stochastic Partial Differential Equations in Optical Communication Problems

In this paper we present examples of stochastic partial differential equations of the "multiplicative noise type" arising from laser communication problems. The basic origins and generic structure of these equations are described and their relation to general quantum estimation and filtering theory explained. The major part for the paper is devoted to explicitly analyze certain examples arising from practical applications and to provide exact or approximate solutions with the help of the underlying physical theories. Directions from future theoretical work are discussed.