Recent progresses of optical code-division multiple access (OCDMA) system are introduced. En/decoders based on fiber Bragg grating (FBG) for 2-dimensional incoherent OCDMA and coherent OCDMA are addressed, using fiber grating arrays and superstructured FBG (SSFBG) as en/decoders respectively, which is most likely to be practical. A novel equivalent phase shift SSFBG is analyzed, the method requires only submicrometer precision to be in control, which reduces the production cost of en/decoder greatly. The principle and comparison of three kind of optical threshold devices, such as nonlinear optical loop mirror, periodically-poled lithium niobate waveguide and dispersion-flattened fiber are emphatically discussed. Optical threshold devices can compress the decoding signal, eliminate the multiple access interference, optimize the detection capability and improve the bit error rate (BER) performance. Coherent OCDMA can produce extremely long and multipolar optical code, while incoherent OCDMA is tunable and have good reconstruction, these two schemes will have great potential application for broadband access network in future.