Generation of mode-locked noise-like pulses in double-clad Tm-doped fibre laser with nonlinear optical loop mirror

An all-fibre, noise-like pulse (NLP) mode locked double-clad thulium-doped fibre laser (DC-TDFL) with integrated figure-of-eight nonlinear optical loop mirror (NOLM) is demonstrated. The mode-locked NLP output has a spectral bandwidth of 14.8 nm centred at 1988.82 nm with a repetition rate of 2.85 MHz. A pulse width and pulse energy of 384 fs and 252.6 nJ respectively is achieved. The proposed laser is capable of generating a high-energy pulse over a broad spectrum, making it a potential candidate for the generation of a supercontinuum output in the mid-infrared region.