Using Free-Spectral Range of Waveguide Gratings to Compensate for Optical CDMA Spectral Flattenness

摘要

Spectrum compensation over an arrayed-waveguide grating (AWG)-based optical code-division multiple access (OCDMA) network coder/decoder (codec) is investigated. Since each network user with different signature address code has different spectral distribution, the non-flattened broadband light source will cause multiple-access interference (MAI). Flattenness compensation scheme is proposed to solve the MAI effects induced by non-flattened light sources. By arranging the same coding scheme but at different coding bands, spectral chips from AWG coder/decoder will incoherently power summed by FSR characteristic of AWG in the photo-detectors to approach a more flattened power level. Performances of signal-to-interference ratio (SIR) are finally evaluated with such compensation method for the discussed OCDMA network codecs.