Patent ID: 8737780

Claim:
A method for writing a Bragg grating in a glass optical waveguide, the Bragg grating reflecting light at a target wavelength, said method comprising: a) generating ultrafast optical pulses having a writing wavelength in the range of 300 nm to 700 nm and an intensity sufficient to induce a change of refractive index in the glass waveguide through material densification; b) diffracting the optical pulses using a phase mask to generate an interference pattern having a pitch providing a fundamental Bragg resonance corresponding to said target wavelength; c) impinging the interference pattern on a region of the waveguide to write the same therein, thereby defining said Bragg grating; and d) heating the region of the waveguide containing the Bragg grating to a temperature above a temperature threshold and for a predetermined heating period, said temperature threshold and heating period being sufficient to substantially reduce photoinduced losses in said waveguide.