Tunable thin-film filters based on thermo-optic semiconductor films

摘要

Thermo-optic layers of thin film semiconductors are deposited by PEVCD to create thermally tunable bandpass filters for WDM optical networks. Amorphous semiconductor films, adapted from the solar cell and display industries, are the primary ingredient. Single-cavity tunable filters with FWHM as small as 0.085 nm, >40 nm tuning range, and insertion losses ranging 0.2-4 dB depending in design have demonstrated. Key enablers for this new family of index-tunable thin film devices are PEC VD deposition, large internal temperature changes >400C, high conductivity polysilicon heater films, and extremely robust film adhesion. Applications include optical monitoring, add/drop multiplexing, dynamic gain equalization, and dispersion compensation.