| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunable dispersion compensator applicable to a wavelength multiplexing transmission system and featuring wide band, low loss, minimum loss ripple and a large dispersion amount. SOLUTION: The tunable dispersion compensator has such a configuration that light emitted from a collimator is reflected several times by an etalon of 100% single-side reflectance by arranging the etalon and a mirror in parallel or with a slight angle and, thereafter, is made incident to another collimator, and is provided with a tunable mechanism in which the temperature is changed by a heater or the optical length is changed by a piezoelectric element. By using a material having high transparency and high refractive index in usage wavelength range for an etalon substrate, beam divergence due to multiple reflection in the etalon can be narrowed. The light receiving collimator is horizontally moved from the position where the loss becomes minimum when a reflection surface of the etalon surface is virtually made to be a totally reflecting mirror to the side departing from the transmission collimator, and the position where the beam intensity becomes maximum is set to be the center of the light receiving collimator and, thereby, a tunable dispersion amount can be enlarged even in the same loss. COPYRIGHT: (C)2008,JPO&INPIT
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