Super‐Continuum Generation in Graphene‐Based Chalcogenide Slot Waveguide

Abstract

Slot waveguides comprised of Ge 23 Sb 7 S 70 and Si with and without graphene are considered for super-continuum generation in the mid-infrared range. The dispersion characteristics are optimized for the proposed waveguides comprised of Si and Ge 23 Sb 7 S 70 chalcogenide as the core and cladding, respectively with and without graphene sheets embedded in the proposed structure. The proposed waveguide without graphene possesses all-normal dispersion and the super-continuum spectra with bandwidth of 1.75 µm is obtained for a pump with wavelength of 2 µm, peak power of 100 W, and time duration of 50 fs, at 20 dB level. Also, the total length of the waveguide is 8 mm. The optimized structure with three graphene sheets presents flat anomalous dispersion and the super-continuum spectra with bandwidth of 3 µm is obtained for a pump with wavelength, peak power, and time duration of 3 µm, 7 mW, and 50 fs, respectively at 10 dB level. It is demonstrated that the proper dispersion region for super-continuum generation depends on the sign of Kerr-index of the nonlinear material. The proposed waveguides are highly compatible with fabrication technologies for mid infrared applications. IntroductionRecently, super-continuum generation (SCG) has attracted a great deal of interest in the design of broadband optical sources. [1] SCG originates from the interaction between diverse nonlinear and linear effects. The nonlinear effects include self-phase modulation (SPM), [2] cross-phase modulation, [3] soliton formation, [4] soliton fission (SF), stimulated Raman scattering, [5] four-wave mixing (FWM), [6,7] and the main linear characteristics are the dispersion and loss. SCG is applicable in optical coherence tomography, spectroscopy, high-precision frequency metrology, and pulse

On-Chip Supercontinuum Generation Pumped by Short Wavelength Fiber Lasers

“…Gai et al and Shang et al [56][57][58] reported SC generation in Ge11.5As24Se64.5 waveguides pumped by the 1.55 µm laser With increasing pump power, the SC spectra broaden from 1 µm to 2 µm, as shown in Figure 12. GeSbS and GeSbSe were also used to prepare the waveguides since a heavy element Sb, in the glass can improve the optical nonlinearity [59][60][61][62][63][64]. Choi et al succeeded in fab ricating the GeSbS waveguide with a length of 15 mm and obtained SC spectra from 1.28 to 2.12 µm, as depicted in Figure 13, when the waveguide was pumped by 1.55 µm laser with peak power and a pulse width of 340 W and 500 fs, respectively.…”

“…Choi et al succeeded in fab ricating the GeSbS waveguide with a length of 15 mm and obtained SC spectra from 1.28 to 2.12 µm, as depicted in Figure 13, when the waveguide was pumped by 1.55 µm laser with peak power and a pulse width of 340 W and 500 fs, respectively. GeSbS and GeSbSe were also used to prepare the waveguides since a heavy element, Sb, in the glass can improve the optical nonlinearity [59][60][61][62][63][64]. Choi et al succeeded in fabricating the GeSbS waveguide with a length of 15 mm and obtained SC spectra from 1.28 to 2.12 µm, as depicted in Figure 13, when the waveguide was pumped by 1.55 µm laser with peak power and a pulse width of 340 W and 500 fs, respectively.…”