Experimental and theoretical analysis of the optimum decision threshold for varying numbers of active users in a 2-D time-wavelength asynchronous O-CDMA system

We experimentally demonstrate the existence of an optimal decision threshold in an optical code-division-multiple-access (O-CDMA) system and show its relation to the number of active users. Our results show that tuning the decision threshold in an O-CDMA receiver to an optimal point based on the number of active users improves receiver sensitivity by > 3 dB. We also demonstrate a monitoring scheme to estimate the number of active users in an O-CDMA system using harmonics of RF clock tones.