International Telephone and Telegraph Corporation

Gary W Bickel

Mokhtar S Maklad

Charles K Kao

James E Goell

David L Baldwin

George H Sigel, Jr

A multiport optical cable or bus, composed of bundles of parallel fibers interconnected by an optical star structure, has a higher packing fraction and greater efficiency in the mixing and redistribution functions because the star's radiating arms have their individual cladding layers omitted or removed and because they are fused together to form the mixer section or a part of it. Where the numbers of input and output ports and arms are unequal, the unclad arms have their fused portions optically spliced or connected to form a composite mixer section. Several sections may be cascaded, using the same structural principles, to provide additional lower-level optical outputs for control or other purposes. The cladding function for the star structure is provided by separately encasing the radiating arms and mixer section or sections in a light-reflecting material. Preferably, this is a plastic potting compound having an optical index of refraction lower than those of the star arms or mixer portions. Alternatively, a metallic reflective coating may be applied. The invention has particular utility as applied to optical buses comprised of fibers of the plastic clad silica type.

Multiport optical communication system and optical star structure

The optical fiber beam splitter coupler disclosed includes in the first half thereof a first optical fiber having a first core coaxial of a longitudinal axis and a first cladding disposed concentric to and outside the first core. The second half of the coupler includes a concentric core fiber having an inner core coaxial of the longitudinal axis, an inner cladding concentric to and outside the inner core, an outer core concentric to the inner cladding and an outer cladding concentric to the outer core. The adjacent ends of the first fiber and the concentric fiber are polished at 45.degree. angles complementary to one another and are abutted end-to-end to provide an interface therebetween. A mirror surface is deposited on the interface so as to cover either the adjacent end of the outer core or the inner core of the concentric fiber. This arrangement enables the coupling of two different light beams into and/or out of the coupler. Several embodiments are disclosed.

Optical fiber beam splitter coupler

A single fiber of any glass type is cut at a suitable angle and both halves are then polished at the end surfaces. A layer of material having dichroic properties or multiple layers are then deposited on one coupler half and the two halves are rejoinded with the angular faces in alignment. Each of the cut fibers are supported in a potting compound. A third fiber is added relatively transverse to the original fibers in order to receive light from the deposited layer. This fiber is associated with one port, while the other fibers are associated with two other ports, thus providing a three port coupler device.

Optical fiber beam splitter couplers employing coatings with dichroic

Optical fibers of silica and plastic composition are rendered relatively stable to nuclear radiation induced optical losses by preirradiating with a high initial radiation dosage. Subsequent exposure of the radiation hardended fibers produce substantially lower radiation induced optical loss and faster fiber transmission recovery rates.

Radiation hardness of optical fibers

A method and means is disclosed for continuously monitoring an optical fiber's attenuation or loss as it is being formed, which includes: a light source, which may be the heated fiber itself during drawing operations or an external source; passing the light through the fiber being produced; positioning the end of the fiber in a holder adjacent to a light detector, for example a photodiode with or without passing the transmitted light through a filter; detecting the light transmitted by the fiber from the light source; converting the detected light into an electrical equivalent signal; amplifying the signal if necessary and recording or observing the changes in the signal to determine an objective measure of the optical fiber's attenuating characteristic.

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Roanoke, VA, United States of America

Gary W Bickel