Abstract

Over the last decade, the ultrafast fibre laser market has been ambitiously growing, having Ytterbium-Erbium-and Thulium-doped fibre systems as key players. To unleash the full potential for expanding applications, the fibre laser system has to present highly integrated, cost-effective, rugged, compact turn-key solutions. Broadband wavelength tuneability can ensure one more level of versatility for laser systems and extend areas of their applications. Principle limitations of achieving stable ultrashort pulse generation and wide tuning wavelength ranges are generally defined by the spectral bandwidth of the gain and traditional mode-locking techniques, typically relying on the implementation of expensive semiconductor structures or elaborated cavity designs. This is particularly true for Tm-doped laser systems operating at the short-wave infrared wavelength region, where the available range of mode-locking techniques appears to be less efficient. They are less mature than Yb- and Er-doped counterparts, but their operation band advantageously matches low-loss atmospheric transmission and absorption lines of gases and biomolecules, as well as allows deep biological tissue penetration. These factors drive the demand for efficient light sources. This presentation will discuss new possibilities for ultrashort pulse generation, omitting the application of conventional material saturable absorbers or modulation techniques based on the nonlinear optical Kerr effect. Instead, it will cover self-mode-locking methodologies. With the higher need for new mode-locking techniques, we have investigated Tm-doped fibre laser designs. However, all the presented techniques can be applied to other wavelength ranges and rare-earth doping ions.

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