Fourier analysis of index-patterned Fabry-Pérot lasers

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dc.contributor.advisorO'Reilly, Eoin P.
dc.contributor.advisorCorbett, Brian
dc.contributor.authorBoohan, Niallen
dc.contributor.funderScience Foundation Ireland
dc.date.accessioned2025-05-14T14:29:52Z
dc.date.available2025-05-14T14:29:52Z
dc.date.issued2024
dc.date.submitted2024
dc.description.abstractOptoelectronics has the potential to revolutionise mass-produced, consumer-level goods (health, LiDAR, and 6G internet) as it has done for high-tech, specialised applications in metrology, spectroscopy, and telecommunications. To achieve this, key components need to become more structurally robust and easier to manufacture. The index-patterned laser, using a perturbation-based grating within the cavity waveguide, shows great potential as a low-cost, single-frequency light source. However, further research and understanding of the dependence of the device lasing spectrum on the grating perturbations within the cavity is required. This thesis uses a first-order reflection approximation, to allow a Fourier transform-based analysis of grating patterns and cavity structures to improve single-mode selectivity and device yield. We demonstrate how placing the weighted average of the grating perturbation positions closer to the emitting facet can be used to select the lasing mode more strongly. The perturbations interact with the cavity facets to generate modal selection. However, it is not possible to control the facet-to-grating distance precisely enough to ensure a full yield of single-frequency lasers at predetermined wavelengths. We show that the phase difference between the laser light electric field at the perturbations and at the facet can be used to calculate the emission spectrum. This gives us a method for studying these facet position effects on the spectrum. In addition to this, we show how the change in the cavity resonances with length affects mode selection in the device. We analyse for the first time the effects of applying a high-reflectivity facet to the predominant reflecting facet of the cavity for mode selection. We also analyse the effects of higher-order reflections not included in our Fourier method, allowing us to assess its accuracy. The results are supported with a comparison against the experimental data. The grating pattern, position, and facet reflectivity can be used to create devices that have greater spectral purity with lower optical loss. Our ability to relate grating position and mode resonances in the cavity to the calculated device spectrum enables rapid analysis of grating designs for further potential yield improvements. Future modelling work could include applying our designed laser to two-dimensional models with a non-constant refractive index, as this will capture further important device effects not included in our Fourier model.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationBoohan, N. 2024. Fourier analysis of index-patterned Fabry-Pérot lasers. PhD Thesis, University College Cork.
dc.identifier.endpage172
dc.identifier.urihttps://hdl.handle.net/10468/17491
dc.language.isoenen
dc.publisherUniversity College Corken
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/EPSRC Centres for Doctoral Training (CDT) Partnership/18/EPSRC-CDT/3585/IE/EPSRC-SFI CDT in Photonic Integration and Advanced Data Storage/en
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/Research Centres Programme/12/RC/2276/IE/I-PIC Irish Photonic Integration Research Centre/en
dc.rights© 2024, Niall Boohan.
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectIndex-patterned lasers
dc.subjectSingle-mode lasers
dc.subjectFourier analysis
dc.subjectSlotted Fabry-Pérot lasers
dc.subjectDiscrete-mode lasers
dc.subjectGrating design
dc.titleFourier analysis of index-patterned Fabry-Pérot lasers
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD - Doctor of Philosophyen
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