In this paper, we study the performance of the multi photodiode balanced detection (MPBD) scheme in phase induced intensity noise (PIIN) reduction for spectral amplitude coding Optical code division multiple access (SAC OCDMA) systems, when the PIIN is assumed to have a Gamma distribution. The PIIN is signal dependent source of noise which increases with signal power. The MPBD reduces the optical power at photodetection to mitigate the PIIN. To sustain the same average power, a multiple number of photodiodes are used. Our results show that the MPBD can support 67 more simultaneous users than the conventional differential balanced detection. © 2012 IEEE.