The Principle and Application of FBGs based Encoder and Decoder in Optical CDMS Systems

WT5”,6BZ]:The performance of fiber Bragg gratings (FBG) and the characteristics of spread frequency in the system of optical code division multiple access (OCDMA) are described.The principle of encoding/decoding devices based on FBG is analyzed.With these devices,the encoder/decoder for frequency hopping (FH),frequency encoded (FE) and direct sequence (DS) versions of OCDMA systems are investigated,and power efficiency,the ratio of signal to noise (SNR) and the maximum bit rate in the systems are discussed.Compared with the encoder/decoder for DS OCDMA based on fiber delay line and the encoder/decoder for FE OCDMA based on diffraction grating,the one for OCDMA (especially FH OCDMA) based on FBG can make the system have higher power efficiency,better SNR and higher maximum bit rate. [WT5”HZ]