Center for Innovative Technology

Luna Innovations Inc.

Virginia Tech Intellectual Properties, Inc.

Virginia Polytechnic Institute and State University

Fs, Inc.

Other

Axonoptics LLC

Lucent Technologies Inc.

Virginia Commonwealth University

Vpi&su

Kent A Murphy

Richard O Claus

Mark E Jones

Michael F Gunther

Ashish M Vengsarkar

Bernd D Zimmermann

Anbo Wang

Charles Boyd Gause

Angela J Plante

Philip R Couch

Brian R Fogg

Nirmal Velayudhan

Mallika B Sen

Veerendra B Vuppala

Ashish Madhukar Vengsarkar

Michael B Miller

Shufang Luo

Thomas A Wavering

Steven A Stevenson

Jennifer L Elster

Harry C Dorn

Joseph A Schetz

David W Richards

Scott A Meller

Wade J Pulliam

Janice P Stevenson

Shari Feth

Timothy A Bailey

Jonathan A Greene

Ricky L Crotts

Vikram Bhatia

Sridhar Gollapudi

Sanjay Sudeora

Kimberley D Bennett

Randy L Waldron

Jonathan Greene

David A Kapp

An apparatus includes a laser source configured to output laser light at a target frequency, and a measurement unit configured to measure a deviation between an actual frequency outputted by the laser source at a current period of time and the target frequency of the laser source. The apparatus includes a feedback control unit configured to, based on the measured deviation between the actual and target frequencies, control the laser source to maintain a constant frequency of laser output from the laser source so that the frequency of laser light transmitted from the laser source is adjusted to the target frequency. The feedback control unit can control the laser source to maintain a linear rate of change in the frequency of its laser light output, and compensate for characteristics of the measurement unit utilized for frequency measurement. A method is provided for performing the feedback control of the laser source.

Integrated optics reflectometer

A method for imagining and treating a body employing at least one trimetallic nitride template endohedral metallofullerene compound is disclosed. The compound has at least one diagnostic and at least one treatment atom encapsulated within a fullerene cage. The two atoms are different from each other. The compound is administered into a body, traced, and allowed to react at a targeted area of the body.

Imaging and treatment method for body

A flexible microbend device for attachment to an optical fiber is provided. The device comprises an upper bending element grid having at least one flexible element and a lower bending element grid having at least one flexible element. The upper bending element grid alternately engages the lower bending element grid. The flexible microbend device is attached to an optical fiber to form a sensor. The sensor may be either embedded in a host material or attached to a structure to detect various stresses or strains.

Flexible fiber optic microbend device, with interlocking flexible fibers, sensors, and method use

A fiber optic wall shear stress sensor is presented. The sensor comprises a floating head supported by a physical arrangement. At least one optical fiber is positioned in an operable relationship to the floating head wherein an interferometric region is formed between the floating head and each optical fiber. The interferometric region changes in response to a shear force on the floating head.

Fiber optic wall shear stress sensor

An optical waveguide sensor having high refractive index sensitivity over a range of ambient refractive indices is provided. The sensor comprises a core having at least one long period gating disposed therein. An inner and outer cladding region, each cladding region having an effective refractive index. The total effective refractive index of the inner cladding region and the outer cladding region is approximately equal to but not greater than the effective refractive index of an environmental parameter to be sensed. These optical waveguide sensors are useful for measuring changes in a variety of environmental parameters.

Optical waveguide sensors having high refractive index sensitivity

An optical sensor arrangement is provided. The arrangement comprises a light source coupled to an optical waveguide. The optical waveguide has at least one long period grating that promotes an excitation of confined propagating light into higher order modes causing an excitation of a sensing mechanism. A detector is coupled to the optical waveguide to detect a resulting optical signal.

Optical sensor arrangement

A single-ended long period grating optical device is presented. The single-ended optical device comprises an optical waveguide having at least one core mode and a plurality of cladding modes. At least one long period grating couples light from the core mode to the cladding modes. A reflector is positioned in an operable relationship to the long period grating, and the reflector reflects a signal. A mode stripper is positioned after the long period grating and removes the cladding modes from a transmitted signal and the reflected signal.

Single-ended long period grating optical device

An optical fiber holder is presented. The optical fiber holder comprises a tube having a longitudinal axis, a first end for receiving an optical fiber, and a recessed second end for protecting the optical fiber tip. An aperture is disposed along a length of the longitudinal axis of the tube for exposing the optical fiber to a sample. The optical fiber holder allows a sample to be tested while avoiding strain and bending influences.

Optical fiber holder

A process for preparing an optical fiber having at least one long period grating with enhanced sensitivity is provided. A length of optical fiber having a refractive index profile is provided. The optical fiber supports a core mode and cladding modes for a range of operational wavelengths. Group indices are identified for the core mode and the cladding modes for a specific wavelength wherein the group indices are equal to each other. A long period grating is written in the optical fiber. The long period grating has a grating defined by the group indices and it couples light from the core mode to a cladding mode proximate to where the group indices are equal. The optical fibers prepared by the present invention may be used for measuring an environmental perturbation where high sensitivity is required.

Process for preparing an optical fiber sensor with enhanced sensitivity

An optical sensor having at least one long period grating disposed within an optical waveguide is provided. The optical waveguide has a refractive index profile. The long period grating has a plurality of index perturbations spaced apart by a periodic distance .LAMBDA.. The long period grating promotes an excitation of confined propagating broadband light into higher order modes that excite a sensing mechanism. The excitation of confined propagating broadband light is spectrally dependent on the periodic distance of the long period grating and the refractive index profile of the optical waveguide.

Optical sensor activation device

An optical sensor is provided. The optical sensor comprises an optical waveguide, at least one long period grating disposed within the optical waveguide and a reactive coating positioned in an operable relationship to the long period grating wherein the reactive coating causes the long period grating to produce a wavelength transmission spectrum functionally dependent on a parameter sensed. Such sensors may be used to measure physical, electrical and chemical parameters within a single system.

Optical fiber long period sensor having a reactive coating

Uniformity of optical coupling of optical elements such as couplers and splitters is improved by heat treatment which causes dopants in the core of an optical fiber to diffuse into material from the cladding layer of the optical fibers from which the optical element is formed, resulting in a substantially homogeneous interior region of the star coupler or splitter. Increased lossiness of the optical element thus formed may be limited by termination of the heat treatment before dopant diffusion reaches equilibrium throughout the fibers so that a portion of the cladding layer of the fibers remains surrounding the substantially homogeneous region where the fibers have been fused together. Dopant diffusion is constrained to a substantially radial direction in each fiber by uniformity of heating over a region where at least two fibers are twisted together. Thus dopant diffusion is highly repeatable and can be readily regulated to provide highly selective, wavelength-dependent coupling between fibers, particularly for multiplexing and demultiplexing applications.

Controlled dopant diffusion for fiber optic coupler

An optical waveguide sensor arrangement for sensing at least one physical parameter is provided. This arrangement comprises an optical waveguide having guided modes, lossy non-guided modes, and a long period grating coupling the guided modes to the lossy non-guided modes wherein the long period grating produces a wavelength transmission spectrum functionally dependent on the physical parameter sensed. A source means provides light to the optical waveguide sensor and an optoelectronic detector, which is positioned in an operable relationship to the optical waveguide sensor, detects light transmitted through the optical waveguide sensor. Lastly, a processing means is attached to the optoelectronic detector for correlating the wavelength transmission spectrum with a numerical value for the physical parameter sensed. The physical parameters sensed by the optical waveguide sensor include: temperature, strain, shape, refractive index and corrosion.

Optical waveguide sensor arrangement having guided modes-non guided

Uniformity of optical coupling of optical elements such as star couplers and splitters is improved by heat treatment which causes dopants in the core of an optical fiber to diffuse into material from the cladding layer of the optical fibers from which the optical element is formed, resulting in a substantially homogeneous interior region of the star coupler or splitter. Increased lossiness of the optical element thus formed may be limited by termination of the heat treatment before dopant diffusion reaches equilibrium throughout the fibers so that a portion of the cladding layer of the fibers remains surrounding the substantially homogeneous region where the fibers have been fused together.

Growing community of inventors

Troutville, VA, United States of America

Kent A Murphy