A system and method for virtual I/Q multiplexing in optical code division for secure local area OFDM includes encoding a wide spectrum signal, which includes a plurality of spectral bins, to provide a complementary spectral coding over at least two channels. The complementary spectral codings are intensity modulated with opposite polarity for each channel. An M-ary Orthogonal Frequency Division Multiplexing (OFDM) signal is modulated using the complementary spectral codings of opposite polarity with separate complementary spectral encoded (CSE) optical codes to provide a virtual in-phase (I) and quadrature (Q) (I/Q) multiplexing for the OFDM signal.