Two-dimensional (2-D) spectral/spatial codes are utilized for optical code division multiple access (OCDMA)-based passive optical network (PON). In this work, 2-D multidiagonal (2D-MD) codes are used for the first time to the best of our knowledge in OCDMA-PON at data rates up to 15 Gbps. 2D-MD codes are very easy to construct and offer zero cross correlation. We showed a simpler implementation compared to similar published work. A complete PON system addressing downstream as well as upstream communication link is demonstrated at data rates up to 15 Gbps. Four downstream wavelengths (1546, 1546.3, 1547.8, and 1548.1 nm) and four upstream wavelengths (1310, 1310.3, 1311.8, and 1312.1 nm) are used to carry the modulated signal over single-mode fiber length of 25 km. The system performance is analyzed using bit error rate and Q-factor parameters for different data rates.