| Popis: |
The four wave mixing (FWM) process in nonlinear media can be used for all optical demultiplexing of high bit-rate optical time division multiplexed channels. Interaction of the optical time division multiplexed signal and a pulsed pump with a repetition frequency equal to the desired output bit-rate, results in generation of a new wave at a new wavelength which carries the information of one of the de-multiplexed channels. Dispersion shifted fiber (DSF) is an adequate nonlinear medium in which the four wave mixing process takes place. In this work a detailed theoretical study of an all-optical demultiplexer based on four wave mixing in dispersion shifted fibers is presented for different demultiplexing input/output bit-rates. The four wave mixing process in dispersion shifted fibers is studied through numerical simulation of the non-linear Schroedinger equation, taking into account ail fiber nonlinearities. The performance of the demultiplexer is characterized in terms of efficiency, Q-factor, suppression of adjacent channels and eye pattern far each de-multiplexed channel. These characteristics are studied for different fiber lengths, pulsewidths, powers, etc. This detailed characterization of the operational conditions of the demultiplexer will reveal its limitations and hints for its optimal design will be proposed. |
