Mechanical strength characteristics of tin-codoped germanosilicate fibre Bragg gratings by writing through UV-transparent coating

A Bragg grating reflector was fabricated through the coating with a centre wavelength of 1544.5 nm, and a peak reflectivity of 100%. Breaking strength of this grating was 61.05 N (4.97 GPa) at a rate of 1% strain/min. The change in the modulus of the coating layer was within 20%.