Dispersion limited fiber-optic CDMA systems with overlapped signature sequences

Abstract

A simple and flexible method is presented and analyzed for counteracting pulse dispersion in a fiber-optic code division multiple access system by allowing the pulses transmitted in each user's code to overlap into neighboring pulse slots. The simultaneous use of the entire channel by users in an optical CDMA system using ultrashort pulses requires minimization of dispersive effects. After establishing a dispersion model, a method of intentionally widening the transmitted pulses to counteract pulse dispersion in an optical CDMA system while maintaining the same high data rate and the same number of users is suggested. It is demonstrated that these widened pulses are much less susceptible to dispersion.