Four-channel Ti:LiNbO3 wavelength division multiplexer for 1.3-µm wavelength operation

A four-channel Ti:LiNbO3 wavelength division multiplexer (WDM) that uses cascaded two-mode-interference dual-channel WDM waveguide structures is demonstrated. Its implementation in integrated-optic form affords ease of fabrication, voltage tunability, and the potential for combining other devices for different functions on the same chip. The device was operated in the wavelength region of 1.3 micron. The channel spacings range from 12 to 15 nm. The channel wavelengths can be electrooptically tuned at the rate of 1 nm/V. The cross talk is measured to be less than -20 dB.