Self-Imaging based Dispersion Compensation: Performance and Tolerance of the System
Transmitting ultra wideband (UWB) pulse signals over optical fiber is a certain sign of chromatic dispersion (CD) existence. CD is a serious problem in optical transmission because the velocity of light depends on the frequencies. The effect is strengthened when the optical pulse gets shorter because its spectrum gets broader. This results in a temporal broadening of the initial pulse. The signal is then deformed during propagation, resulting in inter-symbol interference (ISI). Alteration is more pronounced if the optical signal travels further, yielding to shortening the inter-repeater distance. We propose a method for chromatic dispersion compensation. It is based on the temporal Talbot effect that is observed when a periodic signal propagates through a dispersive medium at a given distance named Talbot distance ZT. Our method consists in adding a portion of a dispersive fiber so that the overall propagation distance corresponds to one specific distance, called a fractional Talbot distance. Because a specific length of a generally long fiber is put into play, the tolerance permitted by the approach needs particular attention.
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