Two-user 2.5Gbps 100km OCDMA transmission experiment using EPS-SSFBG En/decoder

There are three key modules in coherent optical code division multiple access (OCDMA) system: source of ultra-short optical pulse, en/decoder and receiver. Two-user 2.5Gbps OCDMA experiment is shown to achieve 100km transmission using Gain Switch Laser Diode, 63-chip Equivalent phase shift super structured fiber Bragg grating (EPS-SSFBG) phase en/decoder, and threshold adjustable receiver with broadband decision. The match between optical pulse source and en/decoders is also an important issue in OCDMA system design. Half band application for EPS-SSFBG en/decoder is proposed and testified in the experiment. Two receiver schemes, which are bit rate receiver and broadband decision receiver, are compared in experiment. Relationships between BER and decision level&time are observed in the experiment, error free transmission was achieved in the range of 10ps decision time and 17% decision level. Results of the experiment show that OCDMA system with fewer users can be put forward with fairly well performance and acceptable expenditure.