Optical masks prepared by using a liquid-crystal light valve for light-induced photorefractive waveguides

The optical masks prepared by using a LCLV (liquid-crystal light valve) are first proposed for lightinduced photorefractive waveguides in photorefractive materials. Employing this technique, various waveguide structures can be fabricated, e.g., Y- or multiple-branches waveguides, fiber-like waveguides, and Mach–Zehnder-like switches, and even whole optical circuits may be formed. A Y-branches waveguide and a fiber-like waveguide were demonstrated in a LiNbO₃:Fe crystal. Several technical problems, such as intensities, resolutions, writing speed, and so on, were also discussed in detail. Using a LCLV with a fast response and a writing beam with a high intensity, the waveguide structures may be changed in real time.