Abstract: A variable dispersion compensator comprises a substrate, a fiber grating, and a plurality of heater elements. Main heater elements are arranged in a grating range of the fiber grating. A sub-heater element is arranged within the grating range of the fiber grating. Heat from the sub-heater element is used to correct a temperature distribution produced by the main heater elements in the fiber grating to achieve a linear temperature distribution.

Abstract: An optical dispersion compensator comprises a heater unit for heating a fiber grating, a heater controller and a Peltier controller. The fiber grating heater unit includes heater elements formed in line on a quartz substrate and a fiber grating arranged on the heater elements. The fiber grating is secured on the quartz substrate using a cap. A step is formed in the quartz substrate to position the cap relative to the heater elements. The fiber grating is inserted into a groove in the cap to position the fiber grating relative to the heater elements.