Broadband noise-like pulses in fiber laser based on a filter

We report on the generation of broadband noise-like pulses in an Er:Yb doped fiber laser with a tunable bandpass filter in the cavity. Benefit from the filter enhanced spectrum at shorter wavelengths and Raman effect assisted spectrum at longer wavelengths, an excellent flat spectrum with a 3 dB spectral width of 130.2 nm is obtained. This is different from previous traditional methods to achieve broadband noise-like pulses, and the results also represent the widest spectrum directly obtained in an erbium doped fiber laser without the use of any special fibers within the cavity.