The Secretary of State for Defence in Her Britannic Majesty's Government

Qinetiq Limited

The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland

Peter A Lloyd

Alan H Greenaway

Roy McBride

James G Burnett

Philip St John Russell

Paul M Blanchard

Andrew Robert Harvey

Jonathan Cave Knight

Timothy Adam Birks

Julian D Jones

John Kirton

Alan F Cattell

Philip S Russell

David G Luke

An optical fibre bend sensor ( ) measures the degree and orientation of bending present in a sensor length ( ) portion of a fibre assembly ( ). Within a multicored fibre ( ), cores ( ) are grouped in non-coplanar pairs. An arrangement of optical elements ( ) define within each core pair ( ) two optical paths ( ) which differ along the sensor length ( ): one core ( ) of a pair ( ) is included in the first path ( ), and the other core ( ) in the second path ( ). A general bending of the sensor region ( ) will lengthen one core ( ) with respect to the other. Interrogation of this length differential by means of interferometry generates interferograms from which the degree of bending in the plane of the core pair is extracted. Bend orientation can be deduced from data extracted from multiple core pairs.

Optical fibre bend sensor

An optical fiber bend sensor ( ) measures the degree and orientation of bending present in a sensor length ( ) portion of a fiber assembly ( ). Within a multicored fiber ( ), cores ( ) are grouped in non-coplanar pairs. An arrangement of optical elements ( ) define within each core pair ( ) two optical paths ( ) which differ along the sensor length ( ): one core ( ) of a pair ( ) is included in the first path ( ), and the other core ( ) in the second path ( ). A general bending of the sensor region ( ) will lengthen one core ( ) with respect to the other. Interrogation of this length differential by means of interferometry generates interferograms from which the degree of bending in the plane of the core pair is extracted. Bend orientation can be deduced from data extracted from multiple core pairs.

Optical fiber bend sensor

An optical fiber for transmitting radiation comprising two or more core regions, two or more core regions, each core region comprising a substantially transparent core material and having a core refractive index, a core length, and a core diameter, wherein said core regions are arranged within a cladding region, said cladding region comprising a length of first substantially transparent cladding material, having a first refractive index, wherein said first substantially transparent cladding material has an array of lengths of a second cladding material embedded along its length, wherein the second cladding material has a second refractive index which is less than said first refractive index, such that radiation input to said fiber propagates along at least one of said core regions. The cladding region and the core regions may be arranged such that radiation input to said optical fiber propagates along one or more said lengths of said core regions in a single mode of propagation. The optical fiber may be used as a bend sensor, a spectral filter or a directional coupler. The invention also relates to a method of manufacturing a multicore optical fiber.

Multicore optical fibre

Sensor system

A method of electroluminescent panel manufacture in which a doped zinc chalcogenide phospher film--for example manganese doped zinc sulphide, is deposited upon an electrode bearing substrate in the presence of a hydrogen enriched atmosphere--for example a 90%:10% argon:hydrogen atmosphere. This is followed by rapid anneal treatment, the substrate being raised quickly to a temperature of 450.degree. C., or greater, and cooled rapidly. It is preferable that, prior to film deposition, the substrate is pretreated by baking in the hydrogen enriched atmosphere. An additional current density limiting film may be applied--a film of low resistance cermet material--for example silica/nickel 20% Ni in SiO.sub.2, or a film of amorphous silicon.

Electroluminescent device

Growing community of inventors

Farnborough, United Kingdom

Peter A Lloyd