{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/108531"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/108531","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Low threshold random lasing from phase separated optical fibers.","abstract":"In this thesis, a low threshold novel random fiber laser, integrating a passive optical fiber with a phase separated aluminosilicate core – silica cladding as the feedback medium, is proposed and presented. The core exhibits greatly enhanced Rayleigh scattering, therefore requiring a significantly reduced length of scattering fiber (4 m) for lasing. The enhanced Rayleigh scattering was verified through measurements and a new figure of merit called effective power reflectivity was also developed to quantify random feedback. With a Yb-doped fiber as the gain medium, the fiber laser operates at 1050 nm with low threshold power, with a tractable lasing wavelength and maximum linewidth, and possesses an output that can be amplified through conventional means. Furthermore, the laser was found to have a high degree of spatial coherence, spectral broadening with increasing input power, and temporal spectral variation. The random lasing action was confirmed both by the use of RF beat spectra measurements and the trends in the Lévy exponent α obtained from the statistics of spectral intensity variation. Cutback experiments carried out shed light on the evolution of lasing behavior with P-SOF length and the impact of feedback on the lasing behavior. The minimum length of P-SOF required for maximum Rayleigh-distributed feedback was also determined to be ~ 2.5 m. This facile setup and results herein pave the way for further study and applications based on low threshold and compact random fiber lasers.","abstract_html":"In this thesis, a low threshold novel random fiber laser, integrating a passive optical fiber with a phase separated aluminosilicate core – silica cladding as the feedback medium, is proposed and presented. The core exhibits greatly enhanced Rayleigh scattering, therefore requiring a significantly reduced length of scattering fiber (4 m) for lasing. The enhanced Rayleigh scattering was verified through measurements and a new figure of merit called effective power reflectivity was also developed to quantify random feedback. With a Yb-doped fiber as the gain medium, the fiber laser operates at 1050 nm with low threshold power, with a tractable lasing wavelength and maximum linewidth, and possesses an output that can be amplified through conventional means. Furthermore, the laser was found to have a high degree of spatial coherence, spectral broadening with increasing input power, and temporal spectral variation. The random lasing action was confirmed both by the use of RF beat spectra measurements and the trends in the Lévy exponent α obtained from the statistics of spectral intensity variation. Cutback experiments carried out shed light on the evolution of lasing behavior with P-SOF length and the impact of feedback on the lasing behavior. The minimum length of P-SOF required for maximum Rayleigh-distributed feedback was also determined to be ~ 2.5 m. This facile setup and results herein pave the way for further study and applications based on low threshold and compact random fiber lasers.","abstract_has_math":false,"creators":["Jagannathan, Srinath"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Dragic, Peter D"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-10-07T21:00:08Z","date_published":"2020-10-07T21:00:08Z","updated_at":"2026-07-22T22:24:48Z","subjects":["Random Lasers, Lasers, Fiber Lasers, Rayleigh scattering, Phase separation, Optical Amplifiers, and Laser Optics"],"languages":["en"],"rights":["Copyright 2020 Srinath Jagannathan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/108531","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dragic, Peter D"]},{"key":"dc:creator","label":"Author","values":["Jagannathan, Srinath"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-10-07T21:00:08Z","2020-07-22","2020-08"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Random Lasers, Lasers, Fiber Lasers, Rayleigh scattering, Phase separation, Optical Amplifiers, and Laser Optics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2020 Srinath Jagannathan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/108531"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this thesis, a low threshold novel random fiber laser, integrating a passive optical fiber with a phase separated aluminosilicate core – silica cladding as the feedback medium, is proposed and presented. The core exhibits greatly enhanced Rayleigh scattering, therefore requiring a significantly reduced length of scattering fiber (4 m) for lasing. The enhanced Rayleigh scattering was verified through measurements and a new figure of merit called effective power reflectivity was also developed to quantify random feedback. With a Yb-doped fiber as the gain medium, the fiber laser operates at 1050 nm with low threshold power, with a tractable lasing wavelength and maximum linewidth, and possesses an output that can be amplified through conventional means. Furthermore, the laser was found to have a high degree of spatial coherence, spectral broadening with increasing input power, and temporal spectral variation. The random lasing action was confirmed both by the use of RF beat spectra measurements and the trends in the Lévy exponent α obtained from the statistics of spectral intensity variation. Cutback experiments carried out shed light on the evolution of lasing behavior with P-SOF length and the impact of feedback on the lasing behavior. The minimum length of P-SOF required for maximum Rayleigh-distributed feedback was also determined to be ~ 2.5 m. This facile setup and results herein pave the way for further study and applications based on low threshold and compact random fiber lasers.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-10-02 without embargo terms","The student, Srinath Jagannathan, accepted the attached license on 2020-07-21 at 21:26.","The student, Srinath Jagannathan, submitted this Thesis for approval on 2020-07-21 at 21:39.","This Thesis was approved for publication on 2020-07-22 at 10:00.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15719 on 2020-10-02 at 15:15:12","Made available in DSpace on 2020-10-07T21:00:08Z (GMT). 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The enhanced Rayleigh scattering was verified through measurements and a new figure of merit called effective power reflectivity was also developed to quantify random feedback. With a Yb-doped fiber as the gain medium, the fiber laser operates at 1050 nm with low threshold power, with a tractable lasing wavelength and maximum linewidth, and possesses an output that can be amplified through conventional means. Furthermore, the laser was found to have a high degree of spatial coherence, spectral broadening with increasing input power, and temporal spectral variation. The random lasing action was confirmed both by the use of RF beat spectra measurements and the trends in the Lévy exponent α obtained from the statistics of spectral intensity variation. Cutback experiments carried out shed light on the evolution of lasing behavior with P-SOF length and the impact of feedback on the lasing behavior. The minimum length of P-SOF required for maximum Rayleigh-distributed feedback was also determined to be ~ 2.5 m. This facile setup and results herein pave the way for further study and applications based on low threshold and compact random fiber lasers.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-10-02 without embargo terms","The student, Srinath Jagannathan, accepted the attached license on 2020-07-21 at 21:26.","The student, Srinath Jagannathan, submitted this Thesis for approval on 2020-07-21 at 21:39.","This Thesis was approved for publication on 2020-07-22 at 10:00.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15719 on 2020-10-02 at 15:15:12","Made available in DSpace on 2020-10-07T21:00:08Z (GMT). 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