Spectral Methods for High-Speed Optical Transmultiplexing and Coding

Abstract

Abstract : This program is demonstrated all-optical methods for generation, processing, and transmultiplexing (data format conversion) of ultrafast lightwave signals. This work is based a generalized space-time processing concept, where ultrafast time-domain signals are converted into the spatial domain, where they can be processed using parallel optical and smart pixel optoelectronic techniques, and then subsequently reconverted back into the ultrafast time domain. The program investigated GaAs/GaAlAs photorefractive quantum wells as a dynamic holographic medium for femtosecond pulse processing in spectral holography systems. Several optical error control code techniques and optical codes have been investigated over the last year, most based optical spectral encoding technique (spectal-null codes) improved bandwidth utilization and drastically reduced dispersion sensitivity can be achieved by encoding individual bits shaped as specific orthogonal waveforms. The results from this work, show that particular orthogonally coded waveforms can indeed be multiplexed on top of each other both in time and frequency and still remain orthogonal at the receiver end. We also show that dispersion, linear and nonlinear chips do not affect the orthogonality properties of these waveforms.