Phase Shift OCDMA Encoding And Decoding Technology Research Based On Chao Sequence

Encoding and decoding is the core technology of OCDMA. Excellent performance of the OCDMA system user address codes is an important prerequisite for practical use. Based on coherent optical phase encoding OCDMA techniques rely on phase changes optical signals, using pseudo-random sequence for encoding and decoding. From this point, in this paper, focuse on the chaotic OCDMA address codes generation and its encoding and decoding device applicaitoin.This paper mainly studies the following aspects:First, analyze the mapping methods and basic characteristics of one-dimensional Logistic mapping, two-dimensional Henon mapping and three-dimensional Lorenz mapping systematically.Second, deduce the same formula structure as Lorenz system from laser rate euations, which indicates the existenc of the chaos in laser system. Analyze the relationship of the laser parameters in the case of the classic Lorenz chaotic parameters. Mainly use define and Jocobian matrix to calculate the system's Lyapunov index, and thus to determine whether the mapping system is in the state of chaos.Finally, use Lorenz chaotic sequences as the address of optical code division multiple access codes for the super-structure Bragg grating (SSFBG) of the phase shift encoding. Use transfer matrix method simulating the correlation properties of between Lorenz chaotic sequences and SSFBG encoder/decoder. The simulation shows that the sequences have good correlation properties using SSFBG.From the point of this paper, there is chaos in lasers as the same structure of Lorenz chao mapping system. Lorenz chao sequence has good correlation characteristics using SSFBG encoder/decoder as an OCDMA code. It should be an option of phase-shift OCDMA codes.