Spectral-Amplitude-Coded OCDMA Optimized for a Realistic FBG Frequency Response

We develop a methodology for numerical optimization of fiber Bragg grating frequency response to maximize the achievable capacity of a spectral-amplitude-coded optical code-division multiple-access (SAC-OCDMA) system. The optimal encoders are realized, and we experimentally demonstrate an incoherent SAC-OCDMA system with seven simultaneous users. We report a bit error rate (BER) of 2.7times10^-8 at 622 Mb/s for a fully loaded network (seven users) using a 9.6-nm optical band. We achieve error-free transmission (BER<1times10^-9) for up to five simultaneous users     

A Standalone Burst-Mode Receiver With Clock and Data Recovery, Clock Phase Alignment, and RS(255, 239) Codes for SAC-OCDMA Applications

We demonstrate a standalone (no global clock) burst-mode receiver (BMRx) for a 7 times 622 Mb/s incoherent spectral-amplitude-coded optical code-division multiple-access system. The receiver provides the following functions: quantization (intensity noise filtering), clock and data recovery, burst-mode functionality (automatic phase acquisition) using a clock phase aligner (CPA), framing (for byte synchronization), and forward-error correction (FEC) using a (255, 239) Reed-Solomon decoder. The receiver provides an instantaneous (zero preamble bit) phase acquisition time for any phase step (plusmn2pi rads) between consecutive packets. With the CPA, we report a zero packet loss ratio (PLR) for up to four simultaneous users and more than a 300-fold improvement in the PLR for a fully loaded system. The BMRx also accomplishes more than 2.5 dB of coding gain, and achieves error-free (bit-error rate ) operation for a fully loaded system.