Numerical Investigation of Supercontinuum Generation Through AsSe2/As2S5 Chalcogenide Photonic Crystal Fibres and Rib Structures

We compare numerically the supercontinuum generation (SCG) phenomenon in the Mid-Infrared (MIR) region through AsSe
₂
/As
₂
S
₅
chalcogenide based optical waveguides namely photonic crystal fiber (PCF) and rib-like structures. The same material combination is used in the two configurations for MIRSCG. Specifically, the studied PCF is composed of a core made of AsSe
₂
glass and a surrounding cladding made of As
₂
S
₅
glass while the AsSe
₂
/As
₂
S
₅
chalcogenide rib waveguide (AsSe
₂
/As
₂
S
₅
ChRW) is filled in its upper cladding by air while the lower one is constituted by the As
₂
S
₅
glass. The comparison is conducted in the anomalous dispersion regime on a very short 1 mm-length of propagation for a 50 fs sechtype pulse in the HE
₁₁
mode at 4 μm wavelength for each waveguide. Despite the ultra-broadband and coherent MIR-SCG spectrum of 18.75 μm in bandwidth obtained with the considered AsSe
₂
/As
₂
S
₅
-PCF, we found that an AsSe
₂
/As
₂
S
₅
-ChRW that has a height H = 1.98 μm and a width W = 5 μm allows a SCG spanning approximately from 1 beyond 20 μm with a very low energy as 0.4 nJ.