Fabrication and characterization of fibre Bragg gratings for near 2 m operation

Reflective fibre Bragg gratings for operation at 2 µm have been fabricated with the use of a lithographic phase mask. Bragg gratings operating at a wavelength of 2025 nm with reflectivities of up to 93.3% were produced with typical bandwidths of 0.4 nm (FWHM). The gratings were written using a pulsed 266 nm UV laser source and were monitored in real time with the use of a scanning monochromator and a 2 µm Tm fibre fluorescence source. The reflection of the fibre Bragg gratings could be made with particular specifications for use as internal fibre mirrors in fibre lasers or in WDM applications.