Carbon-nanotube-based passively mode-locked fiber laser for supercontinuum generation

We demonstrate the generation of a flat supercontinuum (SC) at 1550 nm using photonic crystal fiber (PCF) of normal dispersion when injected by a fiber laser that is passively mode locked by single-wall carbon-nanotube-based saturable absorber (SWNT-SA). The self-started mode-locked laser with a threshold power of 52 mW together with the PCF can generate a SC covering 223 nm over the entire C+L band with less than 7 dB fluctuations. The results are analyzed by solving the nonlinear Schrödinger equation and the flat SC is mainly originated from the interplay of dispersion and self-phase modulation.