A tunable optical dispersion compensator (TODC) for providing chromatic dispersion (CD) compensation of optical signals in a plurality of optical channels comprises: a plurality of CD compensation fibers; a tunable optical switch configurable for directing an optical signal in any of the plurality of optical channels to one of the plurality of fibers, dependent on a central wavelength of the optical signal; a first switch configurable for directing all signals in the plurality of optical channels to a first CD compensation fiber, in a first mode of operation, and for bypassing the first CD compensation fiber in a second mode of operation; and, the first CD compensation fiber, wherein the first switch and the tunable optical switch are connected so as to enable combining CD compensation provided by the first CD compensation fiber and CD compensation provided by any one of the plurality of CD compensation fibers.