Recently optical code division multiple access (OCDMA) encoder/decoder based on phase shifted superstructure fiber Bragg grating (SSFBG) have attracted more attention because of SSFBG can generate long optical codes. The correlation property is fatal to the performance of OCDMA encoder/decoder. To evaluate the practical value of this kind of encoder/decoder the structure and bipolar encoding/decoding principle for OCDMA system based on phase shifted SSFBG are studied. The correlation property is simulated using transmission matrix method. The correlation property versus Bragg wavelength deviation between encoder and decoder because of the deviation of grating period is derived theoretically. Results indicate that the ratio of auto-correlation and cross-correlation is improved with the code length is increased

but the correlation property is more sensitive to the deviation of Bragg wavelength between encoder and decoder with the code length is increased while holding the chip pulse width. To obtain good correlation property the deviation of Bragg wavelength between encoder and decoder using Gold sequences with length 31 and chip duration of 6 ps must less than 0.02 nm. A code can be used with different Bragg wavelengths to implement hybrid wavelength division multiple (WDM) OCDMA system.