Investigation of ultrafast fibre lasers operating on principle of Mamyshev regenerator at short-wave IR wavelength range
Final Report Abstract
Fibre-based ultrafast laser systems play a significant role in the progress of photonic science and technology. They offer cost-effective, robust and energy-efficient technologies, thus facilitating efficient and reliable operation even in harsh environments or clinical settings. From a fundamental aspect, they present an ultimate experimental testbed for studying nonlinear phenomena. Driven by a range of applications, the last two decades demonstrated expanded research interest in Thulium (Tm)-doped fibre lasers, which emission spectrum covers a range spanning from 1.7 to 2.05 μm. Nevertheless, laser generation around the 2 μm wavelength range still lacks the flexibility of fibre laser operation and amplification regimes to a greater degree due to fundamental limits in advanced fibre development. In this project, nonlinear phenomena in ultrafast Tm-doped fibre lasers, particularly the mechanisms underlying self-organisation and generation of ultrashort pulses, have been investigated. The specific focus of the study was on the ultrashort pulse formation by properly designing nonlinear laser cavities, omitting the application of conventional material saturable absorbers and artificial modulators. It was successfully demonstrated that an all-normal dispersion Tm-doped fibre laser cavity, formed by two non-overlapping fibre Bragg grating mirrors (mismatched by several nm), can produce the train of pulses with ps duration, operating in a giant chirp regime. The influence of net cavity dispersion and nonlinearity on the pulse formation dynamics and overall generation stability has been investigated. In addition to experiments related to the Mamyshev oscillator, it was additionally shown that custom-designed Tm-doped fibre can play three roles in the laser cavity, i.e. act as a gain and fast saturable absorber itself, as well as enable broadband central wavelength tuneability, over 90 nm, by controlling its excitation rate via tuning cavity feedback. Since one of the key factors limiting the selfstarting generation of ultrashort pulses in Mamyshev oscillator-based fibre lasers is insufficient nonlinearity, self-starting is generally implemented by seeding an external pulse or modulating the pump. Here, the self-mode-locking phenomena investigated during the project have enabled the passive formation of seed pulses, which were further regenerated in the Mamyshev oscillator scheme. Such a hybrid mode-locking technique presents a new approach to the design of nonlinear Mamyshev mode-locked fibre oscillators. Furthermore, it ensured generation with improved pulse-to-pulse stability and output power in Mamyshev oscillators at around 1.9 µm. Finally, the real-time dynamics of pulses during the build-up process were investigated in temporal and spectral domains by using dispersive Fourier transformation in the pair of highly chirped fibre Bragg gratings.
Publications
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Self-Mode-Locking in a Thulium-doped All-Fibre Ring Laser providing 1.18 nJ, 350 fs Solitons. Conference on Lasers and Electro-Optics, SM3P.4. Optica Publishing Group.
Kirsch, Dennis C. & Chernysheva, Maria
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Tuneable Self-Mode-Locking in a nJ- and fs-class Thulium-doped All-Fibre Laser. 2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 1-1. IEEE.
Kirsch, Dennis C. & Chernysheva, Maria
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Broadband filterless tuneability in self-mode-locked Tm-doped fibre lasers. Fiber Lasers and Glass Photonics: Materials through Applications III, 49. SPIE.
Kirsch, Dennis C.; Bednyakova, Anastasia E. & Chernysheva, Maria
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Gain-controlled broadband tuneability in self-mode-locked Thulium-doped fibre laser. Communications Physics, 5(1).
Kirsch, Dennis C.; Bednyakova, Anastasia; Varak, Petr; Honzatko, Pavel; Cadier, Benoit; Robin, Thierry; Fotiadi, Andrei; Peterka, Pavel & Chernysheva, Maria
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Thulium Ion Pair enriched Saturable Absorber Fibres for high-power Self-Mode-Locking. Optica Advanced Photonics Congress 2022, SoTh2I.2. Optica Publishing Group.
Kirsch, D. C.; Vařák, P.; Honzátko, P.; Peterka, P. & Chernysheva, M.
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Towards a Self-Starting All-Fibre All-Normal Dispersion Mamyshev Oscillator in the 2 μm Band. 2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 1-1. IEEE.
Kirsch, Dennis C.; Likhachev, Mikhail E.; Aleshkina, Svetlana S.; Yashkov, Mikhail V. & Chernysheva, Maria
