AlGaAs-based Semi-Stampfli photonic quasi-crystal fiber for mid-IR supercontinuum generation
摘要
We present a theoretical investigation of photonic quasi-crystal fibers (PQFs) composed of a Stampfli-based lattice structure along with air hole arrays in left–right of PQF region creating a “Semi-Stampfli” lattice for the supercontinuum generation covering the mid-infrared regime. The designed PQF utilizesa a highly nonlinear III–V semiconductor material, aluminum gallium arsenide (AlGaAs), as background material. AlGaAs exhibits a high refractive index (>3), a strong thermo-optic effect and efficient switching ability to second harmonic generation due to its non-centrosymmetric composition, making the proposed material suitable for nonlinear applications. The designing of PQF is followed by the optimization of the structural parameter. Following the optimization study, the designed PQF exhibits a zero-dispersion wavelength (ZDW) at 3580 nm properly defining the normal and anomalous regimes. The effective mode area and nonlinearity at 3580 nm wavelength are measured as 12.8 μm2 and 1370.64 W−1 km−1, respectively. With respect to the extracted ZDW, the central wavelength for pumping is chosen as 3500 nm (falling in the normal regime). A hyperbolic secant pulse having 50 fs width and 16 kW power is injected into the PQF core, resulting in the generation of 1.25–15.5 μm SC band covering 87% of the transparency range of the used material. The proposed PQF offers novelty in design and material composition, correspondingly generating wide-band SC. The extracted wide-band SC from the proposed PQF may be a better alternative for nonlinear applications.