Mid-infrared supercontinuum generation using dispersion-engineered Ge_115As_24Se_645 chalcogenide channel waveguide

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link Abstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge 11.5 As 24 Se 64.5 chalcogenide-glass channel waveguides employing two different materials, Ge 11.5 As 24 S 64.5 or MgF 2 glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 µm the SC never extended beyond 4.5 µm for any of our designs. However, supercontinuum could be extended to beyond 5 µm for a pump wavelength of 3.1 µm. A broadband SC spanning from 2 µm to 6 µm and extending over 1.5 octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 µm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF 2 glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8-7.7 µm (> two octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 µm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8-11 µm (> 2.5 octaves) in a channel waveguide employing MgF 2 glass for its lower cladding with a moderate peak power of 3000 W.

All-Normal-Dispersion Chalcogenide Waveguides for Ultraflat Supercontinuum Generation in the Mid-Infrared Region

“…The nonlinear coefficient is defined as γ = n 2 ω 0 /(cA eff ), where n 2 is the nonlinear refractive index, c is the speed of light in vacuum, and A eff is the effective mode area at the pump frequency. Linear losses are included through α and nonlinear loss is included through α 2 = 9.3 × 10 −14 m/W, representing the two-photon absorption coefficient [19]. Intrapulse Raman scattering plays an important role in the process of SC generation [3].…”

Ultrabroadband mid-infrared supercontinuum generation through dispersion engineering of chalcogenide microstructured fibers

“…Moreover, high absorption in the fluoro-polymer coating on top of the planar waveguide make it difficult to extend the SC beyond 10 µm. Recently we proposed a channel waveguide with air on top and either Ge 11.5 As 24 S 64.5 or MgF 2 glass as the lower cladding material that enables us to extend the SC in the MIR region up to 11 µm [20]. In this work, absorption of MgF 2 glass beyond 9 µm limited the long-wavelength extension of the generated SC.…”

“…Several experimental and theoretical investigations on MIR SC generation have already been reported using both ChG planar wavegiudes [17][18][19][20][21] and ChG fibers [22][23][24][25][26][27]. Gai et al [17] used a 6.6-cm-long rib waveguide made of As 2 S 3 glass to generate a SC spanning from 2.9 to 4.2 µm, when pumped at a wavelength of 3.26 µm with 7.5 ps duration pulses with 2-kW peak power.…”

“…Yu et al [19] later produced a broadband SC extending from 1.8 to 7.5 µm in a 1-cm-long rib waveguide, pumped at 4 µm using 320 fs pulses with 3.26 kW peak power. Recently Karim et al [20] found theoretically that a broadband SC extending from 1.9 to 11 µm could be generated using a 1-cm-long, dispersion-engineered, Ge 11.5 As 24 Se 64.5 channel waveguide pumped using pulses with 3 kW peak power. Liang et al [21] experimentally investigated the MIR SC spanning up to 5 µm in 8-mm-thick bulk dielectric filament made using ZnS with normal GVD regime pumped at 2.1 µm.…”

Numerical Investigation of Mid-Infrared Supercontinuum Generation in GeAsSe Based Chalcogenide Photonic Crystal Fiber Using Low Peak Power

“…8, No. 4; the longest wavelength reached was limited owing to cladding absorption of step-index fiber Hudson et al, 2014;Petersen et al, 2014;Moller et al, 2015;Yu et al, 2015) and cut-off of the asymmetric nature of planar waveguide (Lamont et al, 2008;Gai et al, 2012;Yu et al, 2013;Yu et al, 2014;Karim et al, 2015) design. Photonic crystal fiber based design still attracts researcher attention much to employ it for MIR SC generation due to having no cladding absorption in the long wavelength edge and can be fabricated easily (Fatome et al, 2009;Hu et al, 2010;Weiblen et al, 2010;Wei et al, 2013).…”