One embodiment of the present invention includes a plurality of first
optical elements and a second optical element optically coupled to one
another in cascaded fashion. Each first optical element has a group delay
response characterized by a first period such that only one group delay
peak occurs within a first channel. By contrast, the second optical
element has a group delay response characterized by a second period,
which is less than the first period, such that more than one group delay
peak occurs within the first channel. The preferred embodiment uses
cascaded GT etalons to provide the desired group delay responses. One
advantage of the present invention is that the passband of the dispersion
compensator is increased relative to prior art designs without increasing
insertion losses. Alternatively, the same passband common in prior art
designs may be achieved with fewer GT etalons, thereby reducing insertion
losses.