Ge22As20Se58 glass ultrafast laser inscribed waveguides for mid-IR integrated optics
Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mm were measured along with the waveguide dispersion in the 1 to 4.5 mm range, which is used to estimate the zero-dispersion wavelength. Z-scan measurements of bulk samples have also been performed to determine the nonlinear refractive index. Finally, mid-IR supercontinuum generation has been shown when pumping the waveguides with femtosecond pulses centered at 4.6 mm. Supercontinuum spanning approximately 4 mm from 2.5 to 6.5 mm was measured which, to the best of the authors' knowledge, represents the broadest and the deepest IR supercontinuum from an ultrafast laser inscribed waveguide to date. This work, combined with the long wavelength transmission of GASIR-1 up to 15 mm, paves the way for realizing further ultrafast laser inscribed waveguide devices in GASIR-1 for mid-IR integrated optics applications.