Time–wavelength hybrid optical CDMA system with tunable encoder/decoder using switch and fixed delay-line

Abstract

A novel tunable encoding/decoding scheme based on an arrayed waveguide grating (AWG) and optical switches for time–wavelength hybrid (TWH) optical code division multiple-access (CDMA) systems is proposed. The scheme uses optical switches and fixed delay lines instead of tunable delay lines (TDLs) and utilizes the structure of the TWH optical signature sequences. The advantages of the scheme are that it can be implemented using fewer elements and that the encoded signal suffers lower loss than in those using TDLs. A TWH optical CDMA system for local area network (LAN) applications using the proposed tunable encoder and a simple fixed decoder is examined and its feasibility is experimentally verified.