We designed and experimentally implemented a broadband light-source at 1.7 μm based on a cascaded-modulator pumping source. We generated supercontinuum by pumping a 1 km highly nonlinear dispersion-shifted fiber in the anomalous dispersion region by using a continuous light source combined with a cascaded-modulator. After filtering by using an optical fiber wavelength-division multiplexer, we obtained a broadband light source with a peak wavelength of 1748.9 nm, an output power of approximately 22 dBm, a 20 dB spectral range of 1.6-2 μm, and a corresponding spectral width of approximately 419 nm. By adding the Sagnac filter, a multi-wavelength broadband light source with a frequency period of 2.5 nm and an intensity period of 9.5 dB was obtained. In addition, we analyzed the effects of pump power, wavelength, and repetition rate on supercontinuum broadening.