Electro-optic waveguide TE <--> TM mode converter with low drive voltage.

We have achieved complete electro-optic TE <--> TM mode conversion in Ti-diffused lithium niobate waveguides with as little as a 2.5-V drive. Because, for birefringent substrates like lithium niobate, TE <--> TM conversion is wavelength dependent, our method is potentially useful for wavelength multiplexing and demultiplexing. Three independently controlled mode converters, each with a 15-A filter bandwidth and with center wavelengths separated by 80 A, have been fabricated on a single substrate.