Ultra-Flat Watt-Level All-Fiber Supercontinuum Generation With 3-dB Spectral Bandwidth Spanning From 414 to 1860 nm

We propose a method for generating ultraflat supercontinuum (SC) spanning from the visible to near-infrared (NIR) region. Specifically, through both the numerical simulations and experiments, we confirm that an optimized combination of pump pulse chirp, peak power, and dispersion of highly nonlinear photonic crystal fiber (PCF) can effectively enhance the four-wave mixing (FWM) effect which is dominant for the enhancement of visible spectral components and the extending of the short-wavelength boundary. In the experiment, we produce 4.35-W ultraflat SC covering 414-1860 nm (3-dB bandwidth and 2.12-octave) which encompasses nearly the entire visible band. To the best of our knowledge, this work reports the broadest visible to NIR ultraflat (3-dB bandwidth) SC source ever reported, which also exhibits the maximum visible band coverage. The proposed approach holds significant application potential for fields in which visible band coverage and SC flatness are extremely demanded, such as remote sensing detection.