Spatial filtering properties of the reference beam in an optical heterodyne receiver.
The optical heterodyne receiver with signal-conditioning optics is treated as an active spatial filter for applications in which the signal source is located in the Fresnel field region of the receiver. A theorem is presented and proved which shows that any thin, passive, optical elements placed in the signal beam for the purpose of spatially filtering the signal radiation may be replaced by an equivalent heterodyne reference beam. This theorem can simplify the analysis of optimum optical heterodyne receiver configurations and offers alternative methods for practical implementations.
Mayo
W T
WT