Variable dispersion compensator

摘要

A variable dispersion compensator (1) includes an optical waveguide (8), a temperature controller (3, 5, 6, 7). The optical waveguide has a chirped grating (2) having Bragg wavelength changed along the longitudinal direction. Temperature distribution based on T1(x) is applied to a central portion defined as a region where a distance x from an end of the grating is a range of 20% to 80% of total length of the grating. Temperature distribution based on T2(x) and T3(x) are applied to both end portions defined as two regions extending from both ends of the grating to the central region, respectively. At least one of the T2(x) and T3(x) has distance dependence different from that of the T1(x).