Phase-shifted fiber bragg grating sensor and method for producing same

A method for inscribing a phase shifted Bragg grating in an optical waveguide, comprising the steps of:

• providing the optical waveguide;
• providing a diffractive optical element which incorporates a phase shift that, when exposed to a ultrashort laser pulse, creates an interference pattern on the optical waveguide which has a phase shift in its pattern;
• and
• providing electromagnetic radiation from the ultrashort laser pulse, wherein the electromagnetic radiation has a pulse duration of less than or equal to 5 picoseconds, wherein the wavelength of the electromagnetic radiation has a characteristic wavelength in the wavelength range from 150 nm to 2.0 microns, and wherein the electromagnetic radiation step comprises irradiating a surface of the diffractive optical element with the electromagnetic radiation incident on the optical waveguide, from the diffractive optical element, and being sufficiently intense to cause the permanent change in index of refraction in the core of the optical waveguide when exposed to a minimum succession of laser pulses, to form a Bragg grating.