Experiments on using Spatial Light Modulators to realize optical CDMA network coder/decoders

We propose a new scheme in optical code-division multiple-access (OCDMA) system by using liquid crystal (LC) Spatial Light Modulators (SLMs) with programmable bipolar codes. The key to the system performance depends on constructing a decoder that implements a true bipolar correlation using only unipolar signals and intensity detection. In our optical access coding system, the power spectrum is coded with programmable LC-SLMs. The high polarization selectivity of these components coupled with the polarization rotation ability of liquid crystal elements makes access coding switching possible with high extinction ratio and low crosstalk.