CDMA fiber-optic systems with optical hard limiters

Code-division multiple-access (CDMA) technique has recently received substa ntial attention for fiber-optic communication systems, Simultaneous users a re allowed to send their data asynchronously in CDMA fiber-optic systems th rough the assignment of unique "signature codes." The multiple-access inter ference (MAI), which increases with the number of simultaneous users, sever ely limits the user capacity of the systems, An optical hard limiter can be placed at the front end of the desired receiver to reduce the effects of t he MAI, We obtain the bit error probability for the CDMA fiber-optic system s with optical hard limiters. The exact performance analysis is performed a nd the result is the generalization of the analysis in [5], For lambda (c) = 1 codes, the result is not restricted to the case for threshold Th = w, y ielding a more general and useful result than that in [5], The improvement in the performance from using a hard limiter with prime code and extended p rime code is shown, The effect on the choice of decision threshold Th is al so examined.