Titanium-Diffused Lithium Niobate Waveguide Devices

Optical waveguide devices based upon lithium niobate substrates are presently in an advanced state. A large variety of devices have been demonstrated; fabrication parameters have been optimized by several laboratories; and waveguide devices have shown, for example, improved performance as external modulators in long-distance high-bit-rate systems. In fact, prototype research-grade devices are now commercially available. Lithium niobate has several important charateristics that make it attrative for waveguide devices, in particular its good electro-optic and acousto-optic coefficients. However, equally important is the fact that lithium niobate is readily available commercially in large substrates (7.5 cm wafers). Furthermore it is relatively easily processed and its material properties have been studied and documented extensively.