Noise-like pulse generation in 1.95 μm region using bulk α-alumina saturable absorber

This work presents a tapered fiber decorated with bulk alpha-alumina with 4.08% modulation depth and 21.67 MW/cm(2) saturation intensity which was responsible to induce noise-like pulse (NLP) in an eye-safe wavelength region. The light-matter interaction within evanescent field of ultrathin tapered fiber established NLP in a ring configuration of thulium-doped fiber laser with a broad spectral bandwidth of 45 nm centered at 1948 nm wavelength. The NLP was emitted at 11.36 MHz repetition rate in a net anomalous laser cavity. The generated pulse had a maximum pulse energy of 2.46 nJ at 1587 mW pumping power. The robustness of the NLP performance was validated with 3 h stability test, which opens new possibilities for future research of this material in the wavelength of exceeding 1.9 mu m.

Automated summary

This work presents a tapered fiber decorated with bulk alpha-alumina that induces noise-like pulse (NLP) in an eye-safe wavelength region. The NLP is formed through light-matter interaction within an ultrathin tapered fiber in a ring configuration of a thulium-doped fiber laser.