Generation of octave-spanning supercontinuum with 1550-nm amplified diode-laser pulses and a dispersion-shifted fiber

We present a compact supercontinuum source using a dispersion-shifted fiber and an amplified diode-laser pulse source. Gain-switched DFB laser operating at 1550-nm wavelength, which provides 30-ps pulses, was used for generating the seeding pulses. And serially cascaded low-cost EDFAs were employed to boost the peak power of the pulses to more than 1 kW. Single-mode supercontinuum spanning nearly the full near-IR band was obtained by passing the amplified high-power pulses through a dispersion-shifted fiber. By investigating various characteristics of the supercontinuum generation, the walk-off between the spectral components was found to limit the effective interaction length of the spectrum-broadening effects. An optimal length of the fiber to obtain a flat spectrum was determined, which minimizes undesirable excessive Raman effect.