Strong Anti-Stokes and Flat Supercontinuum in Specified Band Based on Non-Degenerate Raman Four-Wave Mixing Modulation

We proposed a method for flat supercontinuum (SC) in specified band based on non-degenerate Raman four-wave mixing (NRFWM) modulation. The dispersion of the photonic crystal fiber (PCF) and peak power of the pump light, are controlled such that the gain of the NRFWM falls in our desired band. This provides a new method for realizing SC with broadband hyperspectral intensities in the short-wavelength direction. By this method we developed a near-infrared flat SC. Its spectral intensity of 3 dB corresponds to a bandwidth of 420 nm at a central wavelength of 800 nm. In addition, the relative intensity of the anti-Stokes light is 75.2%, and 49.6% of the total spectral energy is concentrated in the 610–1030 nm band, which provides a more effective light source for optical coherence tomography (OCT). Using this SC as the light source of OCT can improve the axial resolution to 0.8 μm.