Experimental and Numerical Optimisation of a SESAM Mode-locked Holmium Fibre Laser
Date
2022
Authors
Kolovinos, Alexandros
Editors
Advisors
Veitch, Peter
Ganija, Miftar
Boyd, Keiron
Ganija, Miftar
Boyd, Keiron
Journal Title
Journal ISSN
Volume Title
Type:
Thesis
Citation
Statement of Responsibility
Conference Name
Abstract
The infrared region of the electromagnetic spectrum is an attractive prospect for a variety of pulsed laser applications, including biomedical surgery and imaging, defence, metrology and attosecond science, environmental detection, and range-finding. The aim of this research is to develop a robust, stable, benchtop fibre-based laser source in the mid-infrared region of the spectrum, capable of producing picosecond to femtosecond pulses. This thesis utilises a semiconductor-based absorber to create pulses in concert with various linear and nonlinear optical effects in fibre. To best optimise the laser source, a multi-step approach utilising both numerical MATLAB modelling in concert with experimental techniques. Firstly, over a half-dozen cavity designs were simulated, assembled, and tested, with each utilising alternate combinations and ordering of various fibre laser components to achieve optimal pulse-to-pulse stability, time duration and spectral quality. From these experimental results, the most optimal design was chosen and was fully characterised, in addition to a single pass pumped holmium fibre amplifier. This laser produced 2.92 ps pulses at a 20 MHz repetition rate, with a central wavelength of 2029.1 nm and a 3 dB bandwidth of 4 nm at an average power of 20.3 mW. Lastly, pulse dispersion was optimised using a length of dispersion compensating fibre (DCF). An estimate for the required dispersion compensation was calculated, numerically simulated, and then experimentally implemented via fusion splicing 13 m of DCF and cutting back in 1 m increments, characterising the laser at each length. This process was repeated using 20 cm increments. The optimal length for pulse duration was found to be 7.2 m, where the laser produced 494 fs pulses, and minimised pulse-to-pulse instability indicated by the radio frequency spectrum.
School/Discipline
School of Physics, Chemistry and Earth Sciences
Dissertation Note
Thesis (MPhil) -- University of Adelaide, School of Physics, Chemistry and Earth Sciences, 2023
Provenance
This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals