Abstract: A method and apparatus for inscribing a high-temperature stable Bragg grating in an optical waveguide, comprising the steps of: providing the optical waveguide; providing electromagnetic radiation from an ultrashort pulse duration laser, wherein the wavelength of the electromagnetic radiation has a characteristic wavelength in the wavelength range from 150 nanometers (nm) to 2.

Abstract: T-phase-shifted fiber Bragg gratings in optical waveguides, and methods of formation thereof. Sensing apparatus comprising such gratings using femtosecond pulse duration lasers and specialized transmission diffraction elements or phase masks.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: T-phase-shifted fiber Bragg gratings in optical waveguides, and methods of formation thereof. Sensing apparatus comprising such gratings using femtosecond pulse duration lasers and specialized transmission diffraction elements or phase masks.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.