Design and performance analysis of fiber-optic infinite-impulse response filters.
Design of direct forms of infinite-impulse response digital filters using radiatively tapped fiber-optic delay lines is discussed. Infinite-impulse response filters are attractive because they can provide better magnitude characteristics and sharp transition bands in their frequency response for a smaller number of taps than finite-impulse response filters can. The designs described here use spatial-light modulators and thus can be incorporated into optical adaptive filters for processing light-wave signals. Models of error sources in the fiber-optical realization and their effects on both time- and frequency-response characteristics are explained. Cascading of lower-order subsystems to obtain higher-order filters is discussed. A possible way of reducing the insertion loss using erbium-doped fiber-optic amplifiers is derived.
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Frank
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