3D laser-written silica glass step-index high-contrast waveguides for the 3.5 µm mid-infrared range

Identifier:  PC:2991

Handle: https://hdl.handle.net/20.500.11797/PC2991

Authors:  Martínez, J.; Ródenas, A.; Fernández, T.; Vázquez de Aldana, J.R.; Thomson, R.R.; Aguiló, M.; Kar, A.K.; Solís, J.; Díaz, F.

Abstract:
We report on the direct laser fabrication of step-index waveguides in fused silica substrates for operation in the 3.5 µm mid-infrared wavelength range. We demonstrate core-cladding index contrasts of 0.7%, enabling bends, low-loss coupling to commercial fluoride fibers, and propagation losses of 1.3 (6.5) dB/cm at 3.39 (3.68) µm, close to the intrinsic losses of the glass. We also report on the existence of three different laser modified SiO2 glass volumes, their different micro-Raman spectra, and their different temperature dependent populations of color centers, tentatively clarifying the SiO2 lattice changes which are related to the large index changes