Low scattering loss high temperature stable fiber Bragg grating sensor based on micropore formation and method for producing same

An apparatus for inscribing a Bragg grating in an optical waveguide, comprising:

• an ultrashort pulse duration laser for providing electromagnetic radiation;
• a focusing optical element to focus the electromagnetic radiation from an ultrashort pulse duration laser;
• and
• a diffractive optical element that when exposed to the focused electromagnetic radiation from the focusing optical element produces an interference pattern in the optical waveguide,
• wherein positioning the optical waveguide at a distance with respect to the diffractive optical element along the propagation direction of the electromagnetic radiation where the confocal parameter of line-shaped laser focus with the interference pattern is smallest and the peak intensity in the focus is highest causes the i) negative spherical aberration and conical diffraction caused by the diffractive optical element and ii) chromatic aberration of the focusing optical element and chromatic dispersion of the diffractive optical element to substantially or completely cancel each other out;
• and
• wherein irradiating the optical waveguide with the electromagnetic radiation with the interference pattern forms a Bragg grating, the electromagnetic radiation incident on the optical waveguide being sufficiently intensive to cause permanent, Type II change in the index of refraction within multiple Bragg grating planes in the core of the optical waveguide wherein the Type II change results from at least one micropore formed directly by the focused electromagnetic radiation with the interference pattern when exposed to one of either a single laser pulse or a plurality of laser pulses, wherein said plurality is equal or less than ten.