Wavelength Conversion Using Quasi-Phase Matched LiNbO3 Waveguides

Wavelength converters using quasi-phase matched LiNbO3 (QPM-LN) waveguides are recognized as key devices for future wavelength division multiplexing (WDM) systems. These converters provide unique characteristics such as the simultaneous conversion of WDM channels, a large signal bandwidth, and transparency as regards modulation format. In this review, we describe waveguide fabrication using the annealed-protonexchange and direct-bonding techniques. A direct-bonded ridge waveguide shows a high resistance to photorefractive damage and a -4.6 dB wavelength conversion using a χ(2)-cascaded pumping scheme is successfully demonstrated. Polarization independent wavelength conversion using a LPE-LN substrate is also described.