{"id":{"repo_id":"adelaide","oai_identifier":"oai:digital.library.adelaide.edu.au:2440/136315"},"canonical_url":"https://search.dev.ndltd.org/etd/adelaide/oai:digital.library.adelaide.edu.au:2440/136315","repository":{"repo_id":"adelaide","name":"University of Adelaide","base_url":"https://digital.library.adelaide.edu.au/server/oai/request"},"display":{"title":"Operating Regimes and Automated Control of Holmium and Thulium Non-linear Polarisation Rotation Mode-locked Fibre Optic Lasers","abstract":"Mode-locked fibre lasers have applications in research, defence, biological science, manufacturing and spectroscopy. The aim of this research was to investigate auto- matic control of a passive mode-locking technique known as non-linear polarisation rotation (NLPR) that exploits polarisation differences across a pulse’s profile that manifest due to different intensities. This research seeks to focus on how NLPR laser sources can be made stable, especially at longer wavelengths (such as 2 µm). Three different fibre lasers were developed to investigate different aspects of NLPR. An erbium mode-locked source was used to explore measurement techniques and competing operating regimes. The operating regimes were controlled using a manual polarisation controller. Characterisation revealed that the source produced 570 fs pulses with a central wavelength of 1567 nm, repetition rate of 17 MHz and pulse energy of 3 nJ. A thulium NLPR source was developed to further explore possible automation metrics and characterise a range of additional undesired operating regimes. Automation metrics tested to determine if the laser was continuously mode-locked included discontinuities in Stokes parameters, two-photon absorption signals and amplitude modulation across the radio-frequency spectrum of the laser. Characterisation revealed that the source produced 1.15 ps pulses with a central wavelength of 1990 nm, repetition rate of 21 MHz and pulse energy of 5 nJ. Lastly, a holmium NLPR source with electronic control of the intra-cavity polarisation state was built. To the best of our knowledge, this is the first diode-pumped NLPR mode-locked holmium source in the 2µm waveband. An automation mechanism was devised and implemented. Characterisation revealed that the source produced 770 fs pulses with a central wavelength of 2061 nm, a repetition rate of 17 MHz and pulse energy of 0.41 nJ.","abstract_html":"Mode-locked fibre lasers have applications in research, defence, biological science, manufacturing and spectroscopy. The aim of this research was to investigate auto- matic control of a passive mode-locking technique known as non-linear polarisation rotation (NLPR) that exploits polarisation differences across a pulse’s profile that manifest due to different intensities. This research seeks to focus on how NLPR laser sources can be made stable, especially at longer wavelengths (such as 2 µm). Three different fibre lasers were developed to investigate different aspects of NLPR. An erbium mode-locked source was used to explore measurement techniques and competing operating regimes. The operating regimes were controlled using a manual polarisation controller. Characterisation revealed that the source produced 570 fs pulses with a central wavelength of 1567 nm, repetition rate of 17 MHz and pulse energy of 3 nJ. A thulium NLPR source was developed to further explore possible automation metrics and characterise a range of additional undesired operating regimes. Automation metrics tested to determine if the laser was continuously mode-locked included discontinuities in Stokes parameters, two-photon absorption signals and amplitude modulation across the radio-frequency spectrum of the laser. Characterisation revealed that the source produced 1.15 ps pulses with a central wavelength of 1990 nm, repetition rate of 21 MHz and pulse energy of 5 nJ. Lastly, a holmium NLPR source with electronic control of the intra-cavity polarisation state was built. To the best of our knowledge, this is the first diode-pumped NLPR mode-locked holmium source in the 2µm waveband. An automation mechanism was devised and implemented. Characterisation revealed that the source produced 770 fs pulses with a central wavelength of 2061 nm, a repetition rate of 17 MHz and pulse energy of 0.41 nJ.","abstract_has_math":false,"creators":["McAfee, David Michael"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Veitch, Peter","Ganija, Miftar","Boyd, Keiron"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020","date_published":"2020","updated_at":"2026-07-24T00:50:44Z","subjects":["Ultrafast, physics, mode-locked, non-linear polarisation rotation, fibre, optics, laser"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2440/136315","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Veitch, Peter","Ganija, Miftar","Boyd, Keiron"]},{"key":"dc:creator","label":"Author","values":["McAfee, David Michael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2020"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ultrafast, physics, mode-locked, non-linear polarisation rotation, fibre, optics, laser"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/2440/136315"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Mode-locked fibre lasers have applications in research, defence, biological science, manufacturing and spectroscopy. The aim of this research was to investigate auto- matic control of a passive mode-locking technique known as non-linear polarisation rotation (NLPR) that exploits polarisation differences across a pulse’s profile that manifest due to different intensities. This research seeks to focus on how NLPR laser sources can be made stable, especially at longer wavelengths (such as 2 µm). Three different fibre lasers were developed to investigate different aspects of NLPR. An erbium mode-locked source was used to explore measurement techniques and competing operating regimes. The operating regimes were controlled using a manual polarisation controller. Characterisation revealed that the source produced 570 fs pulses with a central wavelength of 1567 nm, repetition rate of 17 MHz and pulse energy of 3 nJ. A thulium NLPR source was developed to further explore possible automation metrics and characterise a range of additional undesired operating regimes. Automation metrics tested to determine if the laser was continuously mode-locked included discontinuities in Stokes parameters, two-photon absorption signals and amplitude modulation across the radio-frequency spectrum of the laser. Characterisation revealed that the source produced 1.15 ps pulses with a central wavelength of 1990 nm, repetition rate of 21 MHz and pulse energy of 5 nJ. Lastly, a holmium NLPR source with electronic control of the intra-cavity polarisation state was built. To the best of our knowledge, this is the first diode-pumped NLPR mode-locked holmium source in the 2µm waveband. An automation mechanism was devised and implemented. Characterisation revealed that the source produced 770 fs pulses with a central wavelength of 2061 nm, a repetition rate of 17 MHz and pulse energy of 0.41 nJ."]},{"key":"dc:title","label":"Title","values":["Operating Regimes and Automated Control of Holmium and Thulium Non-linear Polarisation Rotation Mode-locked Fibre Optic Lasers"]}]}],"canonical_facts":{"dc:contributor.advisor":["Veitch, Peter","Ganija, Miftar","Boyd, Keiron"],"dc:creator":["McAfee, David Michael"],"dc:date.issued":["2020"],"dc:description.abstract":["Mode-locked fibre lasers have applications in research, defence, biological science, manufacturing and spectroscopy. The aim of this research was to investigate auto- matic control of a passive mode-locking technique known as non-linear polarisation rotation (NLPR) that exploits polarisation differences across a pulse’s profile that manifest due to different intensities. This research seeks to focus on how NLPR laser sources can be made stable, especially at longer wavelengths (such as 2 µm). Three different fibre lasers were developed to investigate different aspects of NLPR. An erbium mode-locked source was used to explore measurement techniques and competing operating regimes. The operating regimes were controlled using a manual polarisation controller. Characterisation revealed that the source produced 570 fs pulses with a central wavelength of 1567 nm, repetition rate of 17 MHz and pulse energy of 3 nJ. A thulium NLPR source was developed to further explore possible automation metrics and characterise a range of additional undesired operating regimes. Automation metrics tested to determine if the laser was continuously mode-locked included discontinuities in Stokes parameters, two-photon absorption signals and amplitude modulation across the radio-frequency spectrum of the laser. Characterisation revealed that the source produced 1.15 ps pulses with a central wavelength of 1990 nm, repetition rate of 21 MHz and pulse energy of 5 nJ. Lastly, a holmium NLPR source with electronic control of the intra-cavity polarisation state was built. To the best of our knowledge, this is the first diode-pumped NLPR mode-locked holmium source in the 2µm waveband. An automation mechanism was devised and implemented. Characterisation revealed that the source produced 770 fs pulses with a central wavelength of 2061 nm, a repetition rate of 17 MHz and pulse energy of 0.41 nJ."],"dc:identifier.uri":["https://hdl.handle.net/2440/136315"],"dc:language.iso":["en"],"dc:subject":["Ultrafast, physics, mode-locked, non-linear polarisation rotation, fibre, optics, laser"],"dc:title":["Operating Regimes and Automated Control of Holmium and Thulium Non-linear Polarisation Rotation Mode-locked Fibre Optic Lasers"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T00:50:44Z"}