Conventional dispersion compensators cannot satisfy the requirement of 40 Gbit/s DWDM systems for accurate control of the dispersion and neither can they do anything about the remnant dispersion or the dispersion variations caused by circumstances.A Tunable Dispersion Compensator(TDC) can adjust the dispersion compensations automatically in line with the system dispersion variations
achieving the ideal compensation effects.In this paper
several dynamic dispersion compensation schemes are presented