The Post Office

Andrew Corporation

Richard Burnaby Dyott

John Leslie Stevenson

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.

Method of making dielectric optical waveguides

A system for detecting a reflected light beam includes a source of coherent light such as a laser beam, an optical fiber spaced away from the source for receiving an incident beam of coherent light from the source at one end of the fiber, means for reflecting a portion of the incident beam back through at least a portion of the fiber to radiate a reflected beam which includes narrow angle signals having a beam width corresponding to that of the incident beam and wide angle signals having a beam width substantially wider than that of the incident beam, receiving means between the source and the optical fiber for receiving the reflected beam and having an optical aperture therein for transmitting the incident beam and the narrow angle signals in the reflected beam, and a projector lens between the receiving means and the optical fiber for directing the incident beam into the optical fiber and for directing the narrow angle signals in the reflected beam into the optical aperture of the receiving means. This system may be used as a velocimeter for determining the velocity of moving particles adjacent the opposite end of the optical fiber from the end that receives the incident light beam. The receiving means typically comprises a mirror for reflecting the wide angle portion of the reflected beam into a photoelectric transducer, or the receiving means may itself be a photoelectric transducer.

System for detecting reflected laser beams

An optical fiber tap for tapping optical energy from an optical fiber includes an optical waveguide positioned adjacent to the fiber for collecting light signals therefrom. The optical waveguide preferably has an index of refraction greater than the index of refraction of the fiber. A coupling material interconnects the fiber and the optical waveguide for conducting light from the fiber into the waveguide, the coupling material preferably having an index of refraction between the indexes of the waveguide and the fiber. A photodetector is coupled to one end of the waveguide for receiving light signals therefrom and converting the light signals to corresponding electrical signals. When the tap is used to remove light from the cladding of an optical fiber, pressure is applied to preselected points on the fiber upstream of the tap to couple optical signals from the fiber core into the fiber cladding. When the tap is used to remove light from the core of an optical fiber from which the cladding has been removed, optical signals are collected directly from the fiber core and no pressure assembly is required.

Optical fiber tap

Optical devices

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.

Optical communications systems

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.

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London, United Kingdom

Richard Burnaby Dyott