Spectrally efficient optical CDMA using coherent phase-frequency coding

We demonstrate feasibility of a spectrally efficient wavelength-division-multiplexing-compatible optical code-division multiple-access system using 16 phase-locked laser lines within an 80-GHz tunable window as frequency bins and an ultrahigh frequency resolution spectral phase encoder-decoder. Coding and decoding using binary [0, /spl pi/] phase chips were demonstrated for four users at 2.5 Gb/s, and a single coded signal was separated from four copropagating signals, with bit-error rate <10/sup -9/.