Title :
Fiber-optic ladder networks for inverse decoding coherent CDMA
Author :
Chang, Y.L. ; Marhic, M.E.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Northwestern Univ., Evanston, IL, USA
fDate :
12/1/1992 12:00:00 AM
Abstract :
Coherent fiber-optic networks are used to improve upon incoherent CDMA schemes. If a single-channel network is used between transmitters and receivers, standard coherent correlation takes place. If several parallel spatial channels (fibers and/or polarizations) are used, ideal inverse decoding can be implemented, with perfect δ-function response of the matched decoder. The two-channel case is studied in detail. The rules for finding inverses of a given coding network and the relationship between matched networks for one-channel decoding and two-channel inverse decoding are given. Phase and frequency differences among stations imply that unwanted signals add up incoherently. The ideal two-channel network with inverse decoding has no loss due to encoding/decoding, only inevitable loss due to the broadcast network. In experiments using a single fiber between a transmitter and a receiver by orthogonal polarizations, δ-function inverse response was observed
Keywords :
code division multiple access; decoding; optical correlation; optical links; broadcast network; coding network; coherent fibre optic ladder networks; encoding; frequency differences; ideal inverse decoding; inverse decoding coherent CDMA; matched decoder; matched networks; orthogonal polarizations; parallel spatial channels; perfect δ-function response; phase differences; receivers; single fiber; single-channel network; standard coherent correlation; transmitters; two-channel case; Autocorrelation; Broadcasting; Decoding; Frequency; Multiaccess communication; Optical fiber LAN; Optical fiber networks; Optical fiber polarization; Optical receivers; Optical transmitters;
Journal_Title :
Lightwave Technology, Journal of
