This paper organizes the performance of twodimensional (2-D) Modified Double Weight (MDW) code for Optical Code Division Multiple Access (OCDMA) system by employing Avalanche Photodiodes (APD) as a gain. To accomplish the perfection system capacity, their cardinality, bit error rates (BER) and noise interferences are analyzed. With 2-D MDW with APD able to recovered the cardinality at least 61%, which able to reduce the BER of 10-9 Obviously, the proposed system maximally suppressed PIIN and shot noise which is a major factor affecting BER at high effective received power (Psr). Thus, this system shows an improvement of the system by applying APD instead of PIN diodes.
