Nonlinear characterization of GeSbS chalcogenide glass waveguides

Abstract

GeSbS ridge waveguides have recently been demonstrated as a promising mid – infrared platform for integrated waveguide – based chemical sensing and photodetection. To date, their nonlinear optical properties remain relatively unexplored. In this paper, we characterize the nonlinear optical properties of GeSbS glasses, and show negligible nonlinear losses at 1.55 μm. Using self – phase modulation experiments, we characterize a waveguide nonlinear parameter of 7 W−1/m and nonlinear refractive index of 3.71 × 10−18 m2/W. GeSbS waveguides are used to generate supercontinuum from 1280 nm to 2120 nm at the −30 dB level. The spectrum expands along the red shifted side of the spectrum faster than on the blue shifted side, facilitated by cascaded stimulated Raman scattering arising from the large Raman gain of chalcogenides. Fourier transform infrared spectroscopic measurements show that these glasses are optically transparent up to 25 μm, making them useful for short – wave to long – wave infrared applications in both linear and nonlinear optics.

Picojoule-level octave-spanning supercontinuum generation in chalcogenide waveguides

“…The supercontinuum generation in the GeSbS waveguide is simulated using the standard split-step Fourier method. The nonlinear parameters are taken from [15,22]. Higher-order dispersion, self-steepening and Raman effects are taken into account.…”

“…More importantly, considering a typical waveguide coupling loss of (7 ± 1) dB, the experimental waveguide pulse energy is between 20 pJ and 32 pJ, which is commensurate with the 26 pJ pulse energy used in the simulation. Compared to [15], this work demonstrates an octave-spanning supercontinuum with much lower pulse energy by optimizing the waveguide geometry to generate a dispersive wave at the short wavelength end. Moreover, due to the low pulse energy, the generated supercontinuum shows near-unity coherence in simulation.…”

“…Some concerns about As-based materials are their toxicity and the photo-darkening effect [14] they exhibit. In this work we fabricate devices using Ge 23 Sb 7 S 70 , which does not oxidize in air and does not show any photodarkening effect unlike other chalcogenides [15]. Octave spanning supercontinuum generation has already been demonstrated in this material [16].…”

Broadband couplers for hybrid silicon-chalcogenide glass photonic integrated circuits

“…At a wavelength of 1550 nm, GeSbS has a refractive index of 2.17, a third order nonlinear index on the order of 1 0 m / W − , and negligible TPA [23,24]. It is important to note that reported values for these properties can vary widely depending on material form (bulk or planar film), measurement wavelength and specific characterization method.…”

Effect of heat treatment on AgI‐rich chalcogenide glasses with enhanced ionic conductivity

“…Alkali‐doped chalcogenide glasses have attracted much attention because of their good glass‐forming ability, low phonon energy, extended infrared transparency, and because of their potential applications in optical fibers, chemical sensors, and solid‐state electrolytes . However, their application scope is often limited owing to their weak mechanical properties and poor thermal stability.…”