Tapered fiber stress sensing based on soliton state tuning of mode-locked fiber laser with GO SA

The strain-sensing fiber laser using the tapered fiber for wavelength tuning and soliton state switching is proposed. It is demonstrated that the continuous wavelength tuning of different solitons can be achieved by adjusting the bending curvature of microfibers. Specifically, by varying the curvature from 0 mm−1 to 0.262 mm−1, the center wavelength of the conventional soliton can be smoothly tuned from 1567.8 nm to 1560.63 nm. Similarly, the wavelength of the bound soliton can be tuned in the range of 1566.3 nm to 1561.2 nm. Furthermore, applying pressure to the microfibers achieved periodic switching of the conventional soliton's spectral width, as well as periodic switching between the conventional soliton and the bound soliton states. It is found that there is the strong linear correlation between the bending curvature and the tuning wavelength. Additionally, numerical simulations confirm that introducing strain into the microfiber can periodically alter the spectral width of the classical soliton and facilitate the transition between the conventional and bound solitons. It is expected to hold promising applications in the fields of water and civil engineering device for detecting.