Optical en/decoder is one of the most crucial factors affecting the performance of the optical code division multiple access (OCDMA). The autocorrelation peak to maximum wing ratio (P/W) and cross-correlation ratio (P/C) are two important parameters to quantitatively evaluate the performance of the en/decoder.Based on the SOI parallel-cascaded coupled micro-ring reflector, a mathematical model of two-dimensional coherent optical en/decoder is established. Influences of the structure parameters including the coupling coefficient, the loss factor, the array distance, and the channel spacing on P/W and P/C ratios are discussed in detail. Results show that for the micro-ring with a radius of 50 μm, when the ring-bus and ring-ring coupling coefficients are 0.6–0.7 and 0.1–0.2, respectively, the propagation loss is lower than 2 dB/cm, the array distance is greater than 3 mm, and when the channel spacing is given between 25–36 GHz, the proposed structure can have an optimal performance of en/decoding.