Tuning and temperature compensation of the air-gap etalon for dense wavelength-division multiplexing application

摘要

An etalon includes a tuning plate in the air-gap between the etalon mirrors. The method of tuning includes selecting a tuning plate that makes the optical length of the etalon slightly less than required for ITU and then rotating the tuning plate through a small angle until tuning is complete. The tuning plate material is selected to provide dispersion compensation and to compensate for thermal expansion of the mirror spacers.