Bookham Technology Limited

Oxsensis Limited

The Science and Technology Facilities Council

Veinsense Ltd

Arnold Peter Roscoe Harpin

John Paul Drake

Stephen Geoffrey Tyler

Andrew George Rickman

Ian Edward Day

Emma Jane Clarissa Dawnay

Stephen James Fasham

Stephen William Roberts

James Stuart McKenzie

Jolyon Richard Tidmarsh

Robert Stevens

David Francis Gahan

An optical sensor () comprises an optical cavity defined by a dielectric body and responsive to one or more physical environmental conditions, and a waveguide () having a terminal end spaced apart from the optical cavity such that light is optically coupled from the terminal end of the waveguide () to the optical cavity. The waveguide () is arranged such that, in use, it is maintained at a first temperature that would not damage the optical coupling to the optical cavity when the dielectric body is maintained at a second temperature sufficient to damage the optical coupling to the optical cavity.

Optical sensor

A method of assembling an optical sensor for measuring pressure and/or temperature is disclosed. The optical sensor is adapted for use in high temperature environments, such as gas turbines and other engines. The method comprises fabricating a sensor element formed of a pill having an enclosed cavity, bonding the pill to a front end of a spacer, bonding a lens to the back end of the spacer to form the optical assembly, aligning an optical fiber to the optical assembly, and fixing the fiber in position by fusing the fiber to the lens.

Method of assembling an optical sensor

An optical sensor is disclosed for measuring pressure and/or temperature. The optical sensor is adapted for use in high temperature environments, such as gas turbines and other engines. The optical sensor comprises an optical assembly having a sensor element, a spacer and a lens arranged along the optical axis. The sensor element is spaced from the lens by the spacer. An optical fiber is coupled to the optical assembly for illuminating the sensor element. The optical assembly is resiliently mounted in a housing such that the optical assembly is insulated from shock to the housing. There is also disclosed a method of assembling the optical sensor.

An optical sensor having a sapphire body is disclosed. A hollow in the sapphire body defines a surface which is used as a surface of a Fabry-Perot cavity. Interferometry is used to detect changes in the length of the Fabry-Perot cavity, and hence changes in, for example, the temperature or pressure of an environment in which the sensor is placed.

A doped slab region is described for use around a ridge waveguide, for controlling the refractive index of the waveguide material. Instead of simply diffusing dopant in from a surface of the slab region adjacent the waveguide, an area of the slab region is etched and dopant diffused in from a side face of the etched region. Thus, the dopant profile is established from a horizontal direction, allowing the profile to be controlled. A simple vertically uniform doping profile can thus be provided, leading to a vertically uniform current density, or an anisotropic wet etch can be applied after the initial etch to provide a profile which concentrates the current density at a selected height in the slab region.

Electro optic modulator

Method of fabricating an integrated optical component

An integrated optical circuit is formed in a silicon layer and supported on a substrate, and a portion of the silicon layer is substantially thermally isolated from the substrate by extending over a recess in the substrate, e.g. in the form of a bridge. Temperature control means are provided to control the temperature of the portion of the silicon layer or of a device provided thereon. A thermal expansion gap may be provided in the portion to accommodate thermal expansion of the portion relative to the substrate.

Thermally isolated silicon layer

A method of providing a point to point connection between two electrical circuit boards ( ) in which a plurality of pairs of optical transceivers are provided, one transceiver of each pair being formed on a first silicon-on-insulator chip ( ) in electrical contact with a first electrical circuit board ( ), and the other transceiver of each pair being formed on a second silicon-on-insulator chip ( ) in electrical contact with a second electrical circuit board ( ). Each optical transceiver comprises a branched rib waveguide comprising a common stem ( ) and first and second branches ( ) extending from the common stem ( ); a fiber connector ( ) for receiving an optical fiber ( ) in communication with the stem ( ) of the branched rib waveguide; a light source ( ) in communication with the first branch ( ) of the branched rib waveguide; and a light receiver ( ) in communication with the second branch ( ) of the branched rib waveguide. Each pair of transceivers is linked by an optical fiber ( ) connected to the stem ( ) of the branched rib waveguide of the first transceiver and to the stem ( ) of the branched rib waveguide of the second transceiver.

Optical link between electrical circuit boards

An optical waveguide, such as a rib waveguide, having a first portion (,) to which a dopant (,) and/or a metal layer (,) is applied to enable an optical property of a second portion of the waveguide to be altered, the first portion (,) having a structure, e.g. being corrugated, the geometry of which is such as to prevent an optical wave being carried in the first portion (,). The dopant (,) and/or metal layer (,) can thus be positioned close to the second portion which carries the optical wave without causing perturbation, e.g. attenuation and/or polarization, of the optical wave.

Optical waveguide having an optically decoupled modulator region

An integrated optical waveguide with an end face, the end face being provided on an end portion with a greater width than the waveguide, e.g. in the form of a T-bar provided at the end of the waveguide, whereby the rounding effect produced by the manufacturing process, e.g. etching, used to form the end face does not affect the flatness of the portion of the end face through which light is transmitted. The T-bar is preferably inclined so the normal of the end face is inclined to the optical axis of the waveguide to reduce back reflection therefrom. A plurality of waveguides may terminate in a common T-bar.

Waveguide end face

An apparatus is provided for coupling an optical fibre to a waveguide on an optical chip, the apparatus comprises a recess in the chip for receiving the optical fiber, the recess comprising a V-groove the side faces of which locate the position of the fiber in directions perpendicular to the optical axis of the fiber so as to position the fibre in alignment with the waveguide, and an end face adjacent the end of the waveguide, the end face of the recess being substantially flat and substantially perpendicular to the plane of the chip with its normal inclined to the optical axis of the waveguide so an optical fiber having an inclined end face can be brought into a close, abutting relationship with the end of the waveguide and brought into rotational alignment therewith about its optical axis by positioning the fiber so its inclined end face lies in planar contact with the end face of the recess.

Coupling optical fibre to waveguide

The present invention is a temperature stable integrated optical device which is substantially insensitive to temperature variations. The device, such as an interferometer, includes sub-sections of a different light transmissive material within the optical pathways. The relative lengths of the two different material waveguides can be selected so as to achieve temperature insensitivity. A suitable balance is to ensure that the ratio of the difference in sub-path lengths of the first and second materials is equal to the ratio of the refractive index gradient with temperature of the second material to the refractive index gradient with temperature of the first material. Preferable materials are silicon and silicon nitride.

Growing community of inventors

Oxford, United Kingdom

Arnold Peter Roscoe Harpin