Optical CDMA with time hopping and power control for multimedia networks

Optical code-division multiple access (OCDMA) for high-speed multimedia transmission is proposed and its performance is investigated. The proposed system introduces time hopping to vary transmission bit rate and power control to control transmission signal performance, which allows various signals with different desired rate and performance. An expression for the bit error rate (BER) of the proposed system is derived and numerical results are shown. An optical power selector (OPS) coupled with a hard limiter are also proposed to improve system performance. The OPS is a device to transmit the instantaneous maximum optical power among input signals. The OPS combined with the optical hard limiter reduces the interference from simultaneous users which results in an improved BER. BER is theoretically derived and numerical results for some parameters are shown. We show that the proposed system significantly improves BER and is an attractive scheme for future multimedia networks.