Citation
Abstract
The free-space channel is an ideal medium for communicating by means of spatially and temporally coherent optical fields. Here we derive the structure of a coherent optical receiver for M-ary signals assuming Poisson detection statistics. Receiver performance is evaluated for an M-ary signal set consisting of orthogonal Walsh-functions under the assumption of high-intensity symbol counts. The asymptotic performance bound is examined in the limit as both the dimension of the signal-set and the receiver bandwidth become arbitrarily large and it is shown that on the average a maximum of nearly three bits of information can be encoded onto each received photon using the above modulation scheme.
Details
- Volume
- 42-66
- Published
- December 15, 1981
- Pages
- 60–66
- File Size
- 531.6 KB