Fiber Bragg gratings inscribed using 800nm femtosecond laser and a phase mask in single- and multi-core mid-IR glass fibers

For the first time, Fiber Bragg grating (FBG) structures have been inscribed in single-core passive germanate and three-core passive and active tellurite glass fibers using 800nm femtosecond (fs) laser and phase mask technique. With fs peak power intensity in the order of 10(11) W/cm(2), the FBG spectra with 2(nd) and 3(rd) order resonances at 1540 and 1033nm in the germanate glass fiber and 2(nd) order resonances at similar to 1694 and similar to 1677nm with strengths up to 14dB in all three cores in the tellurite fiber were observed. Thermal responsivities of the FBGs made in these mid-IR glass fibers were characterized, showing average temperature responsivity similar to 20pm/degrees C. Strain responsivities of the FBGs in germanate glass fiber were measured to be 1.219pm/mu epsilon. (c) 2009 Optical Society of America