Dk. Jacob et al., HETERODYNE LADER SYSTEM EFFICIENCY ENHANCEMENT USING SINGLE-MODE OPTICAL-FIBER MIXERS, Optical engineering, 34(11), 1995, pp. 3122-3129
A theoretical performance analysis of a heterodyne radar system incorp
orating a single-mode fiber receiver has been performed. For our purpo
ses, the performance parameters of interest are the coupling and mixin
g efficiency of the ladar receiver, as they relate to the overall syst
em carrier-to-noise ratio. For a receiver incorporating a single-mode
fiber mixer, the received and local-oscillator fields are matched both
spatially and temporally at the detector, yielding 100% mixing effici
ency. We have therefore focused our efforts on determining an expressi
on for the efficiency with which a diffuse return from a purely speckl
e target can be coupled into the receiving leg of a monostatic, untrun
cated cw radar system. Through numerical analysis, the expected coupli
ng efficiency for a ladar system with negligible truncation of the tra
nsmit beam has been determined to be 30.6%.