Integrated optics thin film devices and fabrication thereof

There is disclosed a class of integrated optics devices comprising a variety of optical elements such as waveguides, lenses, couplers and the like, and a method of fabrication thereof. In particular, there is disclosed an aberration-free geodesic lens for integrated optics devices. In these devices, photo-induced refractive index changes in chalcogenide glass films may be used to fabricate a radial index of refraction distribution profile in order to form a lens. By varying the exposure of the thin film to ultra-violet light, variable index of refraction profiles may be formed. The variable profile may itself form the lens or, preferably, a thin film may be deposited on an aspherical geodesic lens in order to provide correction of focal length, thus reducing the mechanical tolerances required in the grinding process. These devices thus permit a degree of freedom heretofore unobtained in thin film optical waveguides for use in such devices as a spectrum analyzer operating at the 0.9 to 1.0 micrometer region of the infrared. An important advantage of this approach is that it is compatible with the use of high index of refraction materials, which are basic materials for electro-optic and acousto-optic devices.