Electro-optic polarization converter with programmable spectral output in lithium niobate

An electro-optic polarization converter with programmable spectral output produced on lithium niobate at the 1530 nm wavelength regime is reported. Programmability is achieved by applying spatially periodic weighted voltages on interdigital electrode sets to independently adjust the coupling coefficients, and is controlled electronically via a personal computer interface. The operation of a device with 16 electrode sets as a programmable tunable wavelength filter is demonstrated. The number of selectable channels depends on the number of electrode sets. A 3-dB bandwidth ∼1 nm and a tuning range of 10 nm are measured. Nearest side lobes ?18 dB below the main peak are realized with apodization.