Her Majesty the Queen in Right of Canada as Represented by the Minister of Industry Through the Communications Research Centre Canada

National Research Council of Canada

Jds Uniphase Corporation

Her Majesty the Queen in Right of Canada, as Represented by the Minister

Her Majesty the Queen in Right of Canada, as Represented by the Minister of Industry Through the Communications Research Centre

Her Majesty in Right of Canada as Represented by the Minister of Industry

Dan Grobnic

Stephen J Mihailov

Ping Lu

Huimin Ding

Robert Walker

Christopher W Smelser

Xiaoli Dai

David Coulas

Gino Cuglietta

Robert B Walker

Cyril Hnatovsky

George Henderson

Rune Lausten

Nenad Duricic

Benjamin J Sussman

Philip J Bustard

Gonzalo De La Puente

Claire Callender

Martin Matthews

Duncan G England

David William Charles Markin

Chantal Blanchetiere

Evgueni Ponomarev

Graham Ian Duck

Kyrylo Hnatovsky

Kasthuri De Silva

Nurmemet Abdukerim

Dariusz Sieniawski

Serguei Roupassov

Tinko Eftimov

Haimin Ding

Henry Postolek

Stephen Mihailov

The present invention provides an efficient quantum memory for storing a quantum state of light, such as a photon, for a temporary period of time in a fibre-integrated optical cavity and then recall the quantum state of light and quantum information at a later time with a high probability of success. The present invention uses a nonlinear optical switching mechanism to modify at least one property of the quantum light, or cavity, to trap the quantum light in the optical cavity. Subsequent application of the nonlinear optical switching mechanism switches at least one property of the stored quantum light, or cavity, to release the quantum light from the optical cavity. The present invention also provides quasi-deterministic single-photon generation by temporal multiplexing of a photon pair source integrated within the cavity.

Fibre optic integrated quantum memory for light

An apparatus, method and system are set forth for detection of fluids using Bragg grating sensors, wherein the Bragg grating sensing element comprises an optical fiber having a Bragg grating inscribed therein characterized by optical properties that are dependent upon the periodicity and effective refractive index of the grating, and a package for subjecting the Bragg grating to a change in strain when contacted by a fluid such that periodicity and effective refractive index of the grating changes, whereby when interrogated with laser light any such change in periodicity and effective refractive index may be detected.

Apparatus, method and system for detecting presence of a fluid

A method and apparatus for inscribing a Bragg grating in an optical waveguide, comprising: providing electromagnetic radiation from an ultrashort pulse duration laser, wherein the electromagnetic radiation has a pulse duration of less than or equal to 5 picoseconds, and wherein the wavelength of the electromagnetic radiation has a characteristic wavelength in the wavelength range from 150 nanometers (nm) to 2.0 microns (μm): providing cylindrical focusing optics corrected for spherical aberration: providing a diffractive optical element that when exposed to the focused ultrashort laser pulse, creates an interference pattern on the optical waveguide, wherein the irradiation step comprises irradiating a surface of the diffractive optical element with the focused electromagnetic radiation, the electromagnetic radiation incident on the optical waveguide, from the diffractive optical element, being sufficiently intense to cause the permanent change in the index of refraction in the core of the optical waveguide.

Fiber Bragg grating sensor in polymer-coated ultra-thin optical fibers and method for producing same

Provided is an optical waveguide with an inscribed Bragg grating, where the Bragg grating is stable at high temperature, has low scattering loss and high reflectivity. Also provided is a method for inscribing a Bragg grating in an optical waveguide, the method comprising irradiating the optical waveguide with electromagnetic radiation from an ultrashort pulse duration laser of sufficient intensity to cause a permanent change in an index of refraction within a core of the optical waveguide, where the irradiating step is terminated prior to erasure of a Bragg resonance, and heating the optical waveguide to a temperature and for a duration sufficient to substantially remove a non-permanent grating formed in the optical waveguide by the irradiating step.

Low insertion loss high temperature stable fiber Bragg grating sensor and method for producing same

There is provided an alignment system and method for use in an ultrashort pulse duration laser-based Fiber Bragg Grating (FBG) writing system, the alignment system comprising: clamps configured to hold a coated optical fiber in a position perpendicular to a beam path of an ultrashort pulse duration laser-based FBG writing station; an optical detector; and a control system with an input from the optical detector and an output to adjust parameters of an optical source and the FBG writing station adjust a distance between the optical fiber and an optical source of the writing station based on luminescence generated in a core of the optical fiber as indicated in a signal received at the input from the optical detector.

Automated system for trans-jacket fibre Bragg grating inscription and manufacturing

An apparatus for use with a pulsed laser source for forming an optical grating in a target includes an adjustable telescope having an element with a negative optical power, for generation of a diverging optical beam, so that the optical beam has adjustable divergence upon exiting the telescope while focusing of light inside the telescope is avoided. A transmission diffraction grating is disposed in the optical beam exiting the telescope, for forming an optical interference pattern on the target. Optical gratings with different grating periods may be formed by adjusting the divergence of the optical beam exiting the telescope. Lack of tight focal spots inside the telescope enables use of ultrashort pulse duration, high peak intensity laser sources.

Forming an optical grating with an apparatus providing an adjustable interference pattern

A method of producing a thermally stable grating allows the grating to be placed in environments where temperatures reach 1000&#xb0; C. These gratings may be concatenated so as to form a sensor array. The method requires a step of lowering the characteristic intensity threshold of a waveguide by at least 25%, followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures of at least 10 hours at a temperature of at least 1000&#xb0; C. Pre-writing a Type I grating before writing a minimal damage Type II grating lowers the characteristic threshold of the waveguide so that a stable low damage type II grating can be written; alternatively providing a hydrogen or deuterium loaded waveguide before writing the grating lowers the characteristic threshold of the waveguide.

High temperature stable fiber grating sensor and method for producing same

A method of producing a thermally stable grating allows the grating to be placed in environments where temperatures reach 1000&#xb0; C. and where the grating is relatively stable and has very low loss from scatter. These gratings have spectral characteristics that allow them to be concatenated so as to form a sensor array. The method requires a step of lowering the characteristic intensity threshold of a waveguide by at least 25%, followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures of at least 10 hours at a temperature of at least 1000&#xb0; C. Pre-writing a Type I grating before writing a minimal damage Type II grating lowers the characteristic threshold of the waveguide so that a stable low damage type II grating can be written; alternatively providing a hydrogen or deuterium loaded waveguide before writing the grating lowers the characteristic threshold of the waveguide.

A method of inducing birefringence in an optical waveguide is disclosed wherein the waveguide cladding is irradiated with energy of a sufficient intensity so as to induce a stress in the optical waveguide so as to cause a multitude of spaced stress induced regions within the cladding of the optical waveguide such that there are 10 to 5000 spaced regions per mm and wherein the stress induced regions are proximate the core greater than 2 microns distance from the core-cladding interface. This waveguide has numerous uses, for example a fiber sensor.

Method of changing the birefringence of an optical waveguide by laser modification of the cladding

An optical sensor for sensing information relating to an analyte liquid or gas, has a a planar substrate having a refractive index n. The planar substrate supports a ridge waveguide having an unclad top portion having a refractive index n. The substrate serves as cladding layer for the ridge waveguide at a location where the ridge waveguide contacts the substrate. A Bragg grating inscribed in the ridge waveguide has two modes for providing information relating to both temperature and refractive index of the surrounding analyte liquid or gas. A cladding mode has a different response to the analyte when compared to a Bragg resonance response. Both modes have a same reaction to temperature, wherein said Bragg grating is formed within the unclad region of ridge waveguide, wherein n&#x3c;n. Advantageously multiple parameters can be sensed using only a single Bragg grating.

Ridge waveguide optical sensor incorporating a Bragg grating

A method of increasing the refractive index in a photosensitive glass is disclosed so as to induce an refractive index change of at least 10within a region of the glass. The method includes the step of providing a hydrogen or deuterium loaded doped glass material wherein a dopant within the glass is photosensitive to infrared radiation in the presence of hydrogen or deuterium. The hydrogen or deuterium loaded doped glass is subsequently irradiated with femtosecond pulses of infrared light having an intensity of at least 10W/cmand less than 5&#xd7;10W/cm.

Method of increasing photosensitivity of glasses to ultrafast infrared laser radiation using hydrogen or deuterium

Fiber Bragg gratings were written in pure silica photonic crystal fibers and photonic crystal fiber tapers with 125 fs, 800 nm IR radiation. High reflectivites were achieved with short exposure times in the tapers. Both multimode and single mode grating reflections were achieved in the fiber tapers. By tapering the photonic crystal fibers scattering that would otherwise have occurred was lessened and light external to the fiber could reach the core effectively to write a grating.

Method of changing the refractive index in a region of a core of a photonic crystal fiber using a laser

A retro-reflective sensor for sensing mechanical, chemical or temperature related information, is disclosed. The sensor is formed of an optical waveguide suitable for use in-situ in a high temperature environment having a Bragg grating written into a core region thereof with short-pulsed electromagnetic radiation, said optical waveguide having a glass transition temperature substantially higher than that of silica. Preferably the sensor is written into a length of sapphire fiber or within a zirconium waveguide. Preferably the pulse duration of the short pulsed electromagnetic radiation is less than 500 picoseconds.

Optical fiber sensor based on retro-reflective fiber Bragg gratings

The invention relates to an optical waveguide device for monitoring a characteristics of light, e.g. a wavelength. The device incorporates a waveguide, such as an optical fiber, with an embedded tilted Bragg grating operating in a regime of wavelength detuning. The grating is designed to disperse light azimuthally in two or more different directions about the fiber axis, said directions changing with wavelength. A photodetector array is provided for detecting the azimuthal distribution of light. A processor coupled to the photodetector array determines wavelength information from the detected azimuthal distribution of the out-coupled light.

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Ottawa, Canada

Dan Grobnic