Low loss rapidly tunable optical add drop multiplexer in Ti:LiNbO3

Polarization-independent guided-wave electrooptically tunable wavelength filters have been produced in Ti:LiNbO₃ for the 1550 nm regime of the spectrum utilizing static strain-optic effect from a spatially periodic surface film. The 3-dB optical bandwidth (FWHM) of 2.3 nm for a 10.5-mm interaction length is in agreement with theory. Electro-optic tuning of the center wavelength over a range of 20 nm with an RC-limited rise time of 52 ns have been demonstrated. Although only results on the drop function are reported here, the same 4-port device can also add wavelengths via port 2. Increasing the length of the polarization conversion/tuning region and apodization of the polarization converting strain pads can be used to achieve narrower channel bandwidth and higher side lobe suppression. Such devices are in process.