Other

Raymond M Measures

Kexing Liu

Serge M Melle

Tino Alavie

John Douglas Lymer

Roderick C Tennyson

Neil D Glossop

Beck Mason

W Dayle Hogg

Trent Coroy

Tomas Valis

Shawn E Karr

Dayle W Hogg

The present invention discloses a method for demodulating, processing and multiplexing the signals from an array of structurally integrated Bragg grating laser sensors in an optoelectronic element in order that this sensing information can be transmitted from the structure by means of a single channel and a user friendly interconnect or free-space propagation. The invention also discloses a method for determining the wavelength of narrowband optical signals such as arises from Bragg grating laser sensors and includes, for each sensor, processing the optical signal through a spectral filter with a spectral transmission function that can be accurately translated by a control parameter which has been calibrated with respective to wavelength. The filtered signal is compared to the reference signal at different values of the control parameter to determine a value of the control parameter where a predetermined relationship of the spectrally filtered signal and the reference signal is achieved. This allows the wavelength to be determined. Apparatus for carrying out the method is also disclosed. A preferred embodiment involving the use of a multiple quantum well electroabsorption device to perform both spectral filtering and detection is also disclosed. The method and apparatus have particular application with lasers and laser sensing arrangements for smart structures.

Method and apparatus for an optoelectronic smart structure interface

A method and apparatus for measuring the wavelength of spectrally narrow optical signals, particularly from guidedwave structures, is taught, which utilizes a known wavelength dependent transfer function and determining from the resulting signal the wavelength. In a preferred embodiment the spectrally narrow optical signal is divided into at least two signals, followed by optically processing the signals to produce a wavelength dependent change between the signals and determining the wavelength therefrom.

Method and apparatus for measuring the wavelength of spectrally narrow

Disclosed herein is an optical fiber device comprising an optical fiber; the fiber having a first portion with an endface, the endface having a core and a peripheral area around the core, the endface having defined thereon a first region adjacent the core and a second region adjacent the peripheral area; a layer of reflective material located on the endface and confined to the first region, thereby forming a localized reflector thereon.

Fiber optic device with reflector located at splice joint

A damage detection and evaluation system utilizes optical fibers to detect and assess damage to a structure. The optical fibers are intermittently etched in a controlled manner to weaken them so they fracture when a desired load is applied to the structure. Where visual inspection of the optical fibers is used to check for damage, a reference set of optical fibers is used. Where photodetection is used and minimal connections to the structure are required, one end of the optical fiber is made reflecting so an optical connection is only made to the other end. To further simplify the connection, a single input/output optical connection to a demultiplexing/multiplexing chip mounted on or within the structure is provided. Where orthogonal grids of fibers are not possible, the invention provides interdigitated optical fibers and volume backscattering to locate the position of the first fracture along the length of the optical fiber. The entire periphery of a damaged area can then be determined with a set of such interdigitated optical fibers. Again, a single optical interface to the structure can be provided using a demultiplexing/multiplexing chip. In the case of composite materials, the optical fibers are located between specified plys and at a specified orientation for optimum sensitivity.

Damage evaluation system and method using optical fibers

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Thornhill, Canada

Raymond M Measures