Patent ID: 7907344

Claim:
A variable dispersion compensator, comprising: an input light collimator which introduces input light; a group delay characteristic assignment unit in which a plurality of reflective etalons are arranged in face-to-face relation so as to form an optical path by reflection for light introduced from the input light collimator, and which assigns variable group delay characteristics to the light by reflection on the plurality of the reflective etalons; an output light collimator which receives the light to which the variable group delay characteristics are assigned by the group delay characteristic assignment unit; a group delay characteristic control unit which controls the group delay characteristics at the group delay characteristic assignment unit in order to perform dispersion compensation for an optical signal of the light introduced from the input light collimator; a positioning unit which positions a relative positional relationship between an optical axis position and the output light collimator in the case where the light from the input light collimator is led to the output light collimator through reflection on each of incident side planes of the plurality of the reflective etalons; and a positioning control unit which controls the positioning unit so that the relative positional relationship becomes a positional relationship set in association with the group delay characteristics controlled by the group delay characteristic control unit.