Multi-octave supercontinuum generation of optical vortices in an As2S3 photonic crystal fibers with all-normal dispersion

We designed an all-normal flat near-zero dispersion As2S3 photonic crystal fiber (PCF) with orderly arranged air hole rings for generating an orbital angular momentum (OAM) supercontinuum (SC). We optimized the characters of chromatic dispersion and confinement loss compared with previous studies by carefully engineering the PCF. Simulation results show that, by launching a 100 fs 250 kW chirp-free hyperbolic secant pulse at 7 mu m into a 5-mm designed PCF, a 9471-nm SC of OAM(1,1) forms from 757 to 10228 nm at a -40dB level, which covers a 3.7-octave bandwidth. As the peak power increases, the higher-order OAM with a flatter chromatic dispersion profile in the normal dispersion region has a wider bandwidth. They are all highly coherent in the whole spectral range. (c) 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)