{"id":{"repo_id":"heriot-watt","oai_identifier":"oai:ros.hw.ac.uk:10399/5024"},"canonical_url":"https://search.dev.ndltd.org/etd/heriot-watt/oai:ros.hw.ac.uk:10399/5024","repository":{"repo_id":"heriot-watt","name":"Heriot-Watt University","base_url":"https://www.ros.hw.ac.uk/oai/request"},"display":{"title":"Environmentally stable, near-infrared, mode-locked fibre lasers for industrial applications","abstract":"Mode-locked laser systems that show robust operation in the presence of environmental instabilities are desirable for numerous applications in the defence sector and beyond. In this thesis I present the development of two such systems based on fibre-laser architecture and developed for applications in radar and lidar. An environmentally stable, 800 nm, laser operating at 7.2 GHz was developed with a timing jitter of 26 fs (integrated from 10 Hz to 10 MHz) for photonic assisted analogue to digital conversion. A novel method of active stabilisation of the Mach-Zehnder Modulator was demonstrated, which allowed turn-key operation and maintained low jitter mode-locking for > 50 hours. When combined with stabilisation of the cavity length, timing jitters of < 42 fs (10 Hz to 10 MHz) can be achieved for a temperature range of 0 oC to 50 oC. A 1.5 µm, passively mode-locked erbium fibre laser was developed for non-line-of-sight lidar applications. The laser had a native repetition rate of 22.6 MHz and an average power of 0.6 mW. The laser output was pulse-picked and amplified to provide a repetition rate of 11.3 MHz and an average power of 354 mW. An innovative strategy was demonstrated to mitigate Q-switching instabilities. The laser was validated to be robust against vibration, shock and temperature, as required for its intended application.","abstract_html":"Mode-locked laser systems that show robust operation in the presence of environmental instabilities are desirable for numerous applications in the defence sector and beyond. In this thesis I present the development of two such systems based on fibre-laser architecture and developed for applications in radar and lidar. An environmentally stable, 800 nm, laser operating at 7.2 GHz was developed with a timing jitter of 26 fs (integrated from 10 Hz to 10 MHz) for photonic assisted analogue to digital conversion. A novel method of active stabilisation of the Mach-Zehnder Modulator was demonstrated, which allowed turn-key operation and maintained low jitter mode-locking for &gt; 50 hours. When combined with stabilisation of the cavity length, timing jitters of &lt; 42 fs (10 Hz to 10 MHz) can be achieved for a temperature range of 0 oC to 50 oC. A 1.5 µm, passively mode-locked erbium fibre laser was developed for non-line-of-sight lidar applications. The laser had a native repetition rate of 22.6 MHz and an average power of 0.6 mW. The laser output was pulse-picked and amplified to provide a repetition rate of 11.3 MHz and an average power of 354 mW. An innovative strategy was demonstrated to mitigate Q-switching instabilities. The laser was validated to be robust against vibration, shock and temperature, as required for its intended application.","abstract_has_math":false,"creators":["Hill, Calum"],"institution":"Engineering and Physical Sciences","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Reid, Derryck"],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-02","date_published":"2021-02","updated_at":"2026-07-24T02:31:05Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10399/5024","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Reid, Derryck"]},{"key":"dc:creator","label":"Author","values":["Hill, Calum"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-01-22T12:32:30Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-01-22T12:32:30Z","Previously restricted access until 28.09.2023."]},{"key":"dc:date.issued","label":"Date","values":["2021-02"]},{"key":"dc:publisher","label":"Institution","values":["Engineering and Physical Sciences"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"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":["http://hdl.handle.net/10399/5024"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Mode-locked laser systems that show robust operation in the presence of environmental instabilities are desirable for numerous applications in the defence sector and beyond. In this thesis I present the development of two such systems based on fibre-laser architecture and developed for applications in radar and lidar. An environmentally stable, 800 nm, laser operating at 7.2 GHz was developed with a timing jitter of 26 fs (integrated from 10 Hz to 10 MHz) for photonic assisted analogue to digital conversion. A novel method of active stabilisation of the Mach-Zehnder Modulator was demonstrated, which allowed turn-key operation and maintained low jitter mode-locking for > 50 hours. When combined with stabilisation of the cavity length, timing jitters of < 42 fs (10 Hz to 10 MHz) can be achieved for a temperature range of 0 oC to 50 oC. A 1.5 µm, passively mode-locked erbium fibre laser was developed for non-line-of-sight lidar applications. The laser had a native repetition rate of 22.6 MHz and an average power of 0.6 mW. The laser output was pulse-picked and amplified to provide a repetition rate of 11.3 MHz and an average power of 354 mW. An innovative strategy was demonstrated to mitigate Q-switching instabilities. The laser was validated to be robust against vibration, shock and temperature, as required for its intended application."]},{"key":"dc:title","label":"Title","values":["Environmentally stable, near-infrared, mode-locked fibre lasers for industrial applications"]}]}],"canonical_facts":{"dc:contributor.advisor":["Reid, Derryck"],"dc:creator":["Hill, Calum"],"dc:date.accessioned":["2025-01-22T12:32:30Z"],"dc:date.available":["2025-01-22T12:32:30Z","Previously restricted access until 28.09.2023."],"dc:date.issued":["2021-02"],"dc:description.abstract":["Mode-locked laser systems that show robust operation in the presence of environmental instabilities are desirable for numerous applications in the defence sector and beyond. In this thesis I present the development of two such systems based on fibre-laser architecture and developed for applications in radar and lidar. An environmentally stable, 800 nm, laser operating at 7.2 GHz was developed with a timing jitter of 26 fs (integrated from 10 Hz to 10 MHz) for photonic assisted analogue to digital conversion. A novel method of active stabilisation of the Mach-Zehnder Modulator was demonstrated, which allowed turn-key operation and maintained low jitter mode-locking for > 50 hours. When combined with stabilisation of the cavity length, timing jitters of < 42 fs (10 Hz to 10 MHz) can be achieved for a temperature range of 0 oC to 50 oC. A 1.5 µm, passively mode-locked erbium fibre laser was developed for non-line-of-sight lidar applications. The laser had a native repetition rate of 22.6 MHz and an average power of 0.6 mW. The laser output was pulse-picked and amplified to provide a repetition rate of 11.3 MHz and an average power of 354 mW. An innovative strategy was demonstrated to mitigate Q-switching instabilities. The laser was validated to be robust against vibration, shock and temperature, as required for its intended application."],"dc:identifier.uri":["http://hdl.handle.net/10399/5024"],"dc:language.iso":["en"],"dc:publisher":["Engineering and Physical Sciences"],"dc:title":["Environmentally stable, near-infrared, mode-locked fibre lasers for industrial applications"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T02:31:05Z"}