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 an ultrashort laser pulse, creates an interference pattern with a phase shift on the optical waveguide;
• wherein the ultrashort laser pulse has a pulse duration of less than or equal to 5 picoseconds, wherein the ultrashort laser pulse has a wavelength in the range from 150 nm to 2.0 microns;
• introducing a beam block to remove the effect of phase-shift splitting;
• and
• wherein the ultrashort laser pulse irradiates the optical waveguide with the interference pattern produced by the diffractive optical element, with the light intensity in the interference pattern being sufficiently high to cause a permanent change in the index of refraction in the core of the optical waveguide when exposed to a minimum succession of laser pulses, to form a phase shifted Bragg grating.