Maximizing the bandwidth of supercontinuum generation in As_2Se_3 chalcogenide fibers

Abstract

We describe in detail a procedure for maximizing the bandwidth of supercontinuum generation in As(2)Se(3) chalcogenide fibers and the physics behind this procedure. First, we determine the key parameters that govern the design. Second, we find the conditions for the fiber to be endlessly single-mode; the fiber should be endlessly single-mode to maintain high nonlinearity and low coupling loss. We find that supercontinuum generation in As(2)Se(3) fibers proceeds in two stages--an initial stage that is dominated by four-wave mixing and a later stage that is dominated by the Raman-induced soliton self-frequency shift. Third, we determine the conditions to maximize the Stokes wavelength that is generated by four-wave mixing in the initial stage. Finally, we put all these pieces together to maximize the bandwidth. We show that it is possible to generate an optical bandwidth of more than 4 microm with an input pump wavelength of 2.5 microm using an As(2)Se(3) fiber with an air-hole-diameter-to-pitch ratio of 0.4 and a pitch of 3 microm. Obtaining this bandwidth requires a careful choice of the fiber's waveguide parameters and the pulse's peak power and duration, which determine respectively the fiber's dispersion and nonlinearity.

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

“…SC generation in MIR has increasingly become a focus for research because bright MIR light sources can be used for molecular fingerprint spectroscopy, frequency metrology, optical coherent tomography and microscopy [2,3]. Chalcogenide glasses can provide MIR transparency with sulphides transmitting to beyond 8.5 µm, selenides to 14 µm and tellurites to around 20 µm [4].…”

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

“…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). In our theoretical study, we show that the use of PCF instead of planar and conventional fibers can overcome this limitation and SC spectrum can be extended far into the MIR regime.…”

Original designs of chalcogenide microstuctured optical fibers

“…Numerous simulations and computing studies have shown the high potential of such glassy matrices [37][38][39]. These simulations show that it can be possible to generate light at wavelengths greater than 12 μm in the infrared.…”