Electro-Optically Tunable, Narrowband Ti:LiNbO sub 3 Wavelength Filter.

We report a tunable optical transmission filter for 1.5microns wavelength with a bandwidth of 12angstroms and a tuning range of at least 80angstroms. The filter is based on wavelength dependent polarization conversion in a single-mode waveguide on x-cut y-propagation LiNbO sub 3. It employs a periodic electrode structure with interdigital finger electrodes to provide phase-matched TE-TM mode coupling in the highly birefringent waveguide. Periodically interleaved birefringence tuning electrodes permit continuous tuning of the filter over a range of at least 6 times the filter bandwidth, thus allowing electro-optic tuning over at least 6 resolvable wavelength multiplexed channels.