Optical CDMA-based ATM switches supporting equal-bit-rate and variable-bit-rate communication services

This paper presents the design of new optical ATM switches that use code-division multiple access (CDMA) and strict optical orthogonal codes (OOCs). The cross-correlation and autocorrelation constraints (i.e. λ_c and λ_a) of strict OOCs are always limited to be “1” for incoherent optical processing, regardless of whether an aperiodic or a periodic pulse sequence is input to optical CDMA decoders. Since the coding and correlation of strict OOCs are performed in the optical domain, the processing speed of the proposed ATM switches can be very high. This can support real-time broadband communications. Moreover, the proposed ATM switch can flexibly handle both equal-rate and variable-rate communication services without violating λ_c=λ_a=1 and without any change of the optical CDMA encoders/decoders. In so doing, it can substantially improve the switch flexibility without increasing the system´s complexity