  Fiber optics is one of the highest bandwidth communication channel types in
the current communication industry. The paper is to analyze a typical optical
channel and perform channel equalization using an adaptive modified DFE with
Activity Detection Guidance and Tap Decoupling algorithm. Evaluation can be
made on the employment of the DFE algorithm and with enhancements, like
Fractionally-Spaced equalization and Activity Detection Guidance, to improve
its stability, steady-state error performance and convergence rate. The
successful implementation of the Adaptive FS-DFE with ADG and TD technique
offers an excellent alternative to linear equalization, which is known to be of
little benefit for optical channels because of exorbitant noise enhancement.
The FSE technique, when combined with the DFE, would offer improved
effectiveness to amplitude distortion. As the impulse response of a typical
optical link would have regions that are essentially zero, the employment of
the activity detection scheme with Tap Decoupling would further enhance the
steady-state error performance and convergence rate.
