Generation of Optical Pulses with 69-nm-Wide Broadband Spectrum Directly from a Mode-Locked Yb-Doped Fibre Laser

In the 1 μm band, broadband light sources are usually based on the amplified spontaneous emission (ASE) from a semiconductor diode pumped Yb-doped fibre [1] or In
_x
Ga
_1-x
As
_1-y
P
_y
LED. Coherent broadband sources with flat spectrum are usually generated the supercontinuum from a highly nonlinear fibre [2]. In this contribution, we report a 1 μm coherent broadband source generated directly by a mode-locked Yb-doped fibre laser with a maximum 10-dB spectral width of 69 nm and a maximum 3-dB spectral width of 64 nm. The output spectrum has a good spectral flatness, and covers almost all of the band of ASE from the Yb-doped fibre between 1010 nm and 1080 nm.