Abstract: An opto-electronic element consists of a dielectric optical waveguide having a single crystal core of meta-nitroaniline. The element is made by feeding molten meta-nitroaniline into a hollow fibre along which a temperature gradient exists. Nucleation sets in at one end of the fibre and the temperature gradient is altered to promote crystal growth along the fibre. The element can be used as a polarizer, in isolators, harmonic generators or mixers. The action of the device depends on either the non-linear optical properties of the meta-nitroaniline or the optical anisotropy of the meta-nitroaniline. To make a polarizer the meta-nitroaniline core is surrounded by a cladding having a refractive index lying midway between two of the refractive indices of the meta-nitroaniline.

Abstract: Energy propagating in a dielectric optical waveguide may be transferred from one mode of propagation to another by inducing a spatially undulatory variation in refractive index in the core of the dielectric optical waveguide. Such a variation may be induced by an electro-static field. The electro-static field may be directed either longitudinally of, or transversely of the dielectric optical waveguide. A suitably periodic electro-static field may be generated by positioning a suitable electrode structure about the dielectric optical waveguide. For certain applications it may be desirable to arrange for the spatial period of the electro-static field to vary in a random manner. By arranging for propagating modes to couple to non-propagating modes an optical modulator may be produced.

Abstract: A dielectric optical waveguide can be made by forming a bundle of rods in which a single rod made of glass suitable for forming the core of the dielectric optical waveguide is surrounded by three rods made of a glass suitable for forming the cladding of the dielectric optical waveguide. The bundle of rods is heated and drawn down to a suitable size. By increasing the number of rods in the bundle it is possible to make a dielectric optical waveguide with a plurality of cores.