Variable dispersion compensator

A variable dispersion compensator comprising:

• a first variable dispersion-compensating unit including:
• a pre-compensating section which has:
• a first etalon irradiated with a beam of light from a collimator, the first etalon having a required amplitude reflectance;
• and
• a first mirror inclined at a required angle equal to or greater than zero degrees with respect to the first etalon, the first mirror being disposed facing the first etalon,
• wherein the first etalon of the pre-compensating section reflects the beam of light an “n1” number of times (“n1” is a natural number);
• and
• a post-compensating section which has a second etalon irradiated with the beam of light from the pre-compensating section via another collimator;
• wherein the second etalon has a required amplitude reflectance equal to or greater than the amplitude reflectance of the first etalon, and
• wherein a peak position of wavelength dispersion characteristics of the second etalon is shifted in a wavelength axis of the light more significantly than a peak position obtained from the pre-compensating section;
• and
• a second variable dispersion-compensating unit including:
• a pre-compensating section which has:
• a third etalon irradiated with the beam of light via yet another collimator, the third etalon having a required amplitude reflectance;
• and
• a third mirror inclined at a required angle equal to or greater than zero degrees with respect to the third etalon, the third mirror being disposed facing the third etalon,
• wherein the third etalon of the pre-compensating section reflects the beam of light an “n3” number of times (“n3” is a natural number), and
• a post-compensating section which has a fourth etalon irradiated with the beam of light from the pre-compensating section via a further collimator, the fourth etalon having an amplitude reflectance smaller than the amplitude reflectance of the third etalon;
• wherein the first variable dispersion-compensating unit and the second variable dispersion-compensating unit are cascade-connected to each other.

A variable dispersion compensator comprising:

• a first variable dispersion-compensating unit including:
• a first etalon irradiated with a beam of light from a collimator, the first etalon having a required amplitude reflectance;
• and
• a first mirror disposed in parallel with respect to the first etalon;
• wherein the first etalon of the first variable dispersion-compensating unit reflects the beam of light an “n1” number of times (“n1” is a natural number);
• a second variable dispersion-compensating unit including:
• a second etalon irradiated with the beam of light via another collimator, the second etalon having a required amplitude reflectance;
• and
• a second mirror disposed at a required angle with respect to the second etalon,
• wherein the second etalon of the second variable dispersion-compensating unit reflects the beam of light an “n2” number of times (“n2” is a natural number);
• and
• a third variable dispersion-compensating unit including a third etalon irradiated with the beam of light via yet another collimator, the third etalon having a required amplitude reflectance;
• wherein:
• the first variable dispersion-compensating unit, the second variable dispersion-compensating unit, and the third variable dispersion-compensating unit are cascade-connected to one another;
• and
• each of the etalons independently includes temperature control means, the temperature control means further including an arithmetic converter which sets optimal temperatures of each etalon, based on an assigned amount of dispersion.