{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/108329"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/108329","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Non-reciprocal light transmission in integrated photonic systems via acousto-optic interaction","abstract":"\"Photonic integrated circuits (PICs) are a promising enabling technology for high bandwidth communications and sensors. Presently, all key optical components including lasers, waveguides, and modulators can be mass fabricated on a PIC using foundry-based manufacturing. However, essential non-reciprocal devices such as optical isolators and circulators are not yet available. Commercialized off-chip non-reciprocal systems are primarily based on Faraday rotation in magneto-optic materials. This approach is challenging to implement in integrated photonic systems due to several reasons; the required materials are not available in foundries; each operational wavelength band needs a different material; localization of magnetic field is difficult in PICs and can affect magnetically sensitive systems. One possible solution is the use of spatio-temporal modulation to produce non-reciprocal effect. For instance, a medium can be modulated by a traveling wave so that light propagating in opposite directions experience non-reciprocal frequency and momentum shifts. These \"\"momentum biased system'' do not require special magneto-optic materials and can be produced with common dielectrics that are already present in foundries. In this thesis, we extend this idea and experimentally demonstrate non-reciprocal light transmission using acousto-optic interaction in PICs. Co-fabricated electromechanical transducers are used to launch traveling acoustic waves that modulate integrated photonic components. We also show that the direction of non-reciprocity can be dynamically controlled by changing the acoustic wave direction. Using this approach, we demonstrate a reconfigurable non-reciprocal modulator that can be arranged in a multitude of reciprocal and non-reciprocal configurations by means of an external RF input. The methodology demonstrated in this thesis may enable new avenues for direction-dependent signal processing and optical isolation. Finally, I propose an important next step in the practical evolution of these devices -- a linear optical isolator -- that exhibits ideal characteristics of ultra-low forward loss and high contrast.\"","abstract_html":""Photonic integrated circuits (PICs) are a promising enabling technology for high bandwidth communications and sensors. Presently, all key optical components including lasers, waveguides, and modulators can be mass fabricated on a PIC using foundry-based manufacturing. However, essential non-reciprocal devices such as optical isolators and circulators are not yet available. Commercialized off-chip non-reciprocal systems are primarily based on Faraday rotation in magneto-optic materials. This approach is challenging to implement in integrated photonic systems due to several reasons; the required materials are not available in foundries; each operational wavelength band needs a different material; localization of magnetic field is difficult in PICs and can affect magnetically sensitive systems. One possible solution is the use of spatio-temporal modulation to produce non-reciprocal effect. For instance, a medium can be modulated by a traveling wave so that light propagating in opposite directions experience non-reciprocal frequency and momentum shifts. These ""momentum biased system'' do not require special magneto-optic materials and can be produced with common dielectrics that are already present in foundries. In this thesis, we extend this idea and experimentally demonstrate non-reciprocal light transmission using acousto-optic interaction in PICs. Co-fabricated electromechanical transducers are used to launch traveling acoustic waves that modulate integrated photonic components. We also show that the direction of non-reciprocity can be dynamically controlled by changing the acoustic wave direction. Using this approach, we demonstrate a reconfigurable non-reciprocal modulator that can be arranged in a multitude of reciprocal and non-reciprocal configurations by means of an external RF input. The methodology demonstrated in this thesis may enable new avenues for direction-dependent signal processing and optical isolation. Finally, I propose an important next step in the practical evolution of these devices -- a linear optical isolator -- that exhibits ideal characteristics of ultra-low forward loss and high contrast."","abstract_has_math":false,"creators":["Sohn, Donggyu Benjamin"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Bahl, Gaurav","Vlasov, Yurii","Sinha, Sanjiv","Fang, Kejie"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-08-27T00:51:29Z","date_published":"2020-08-27T00:51:29Z","updated_at":"2026-07-22T22:24:48Z","subjects":["Non-reciprocity","Integrated photonics"],"languages":["en"],"rights":["Copyright 2020 Donggyu Sohn"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/108329","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bahl, Gaurav","Vlasov, Yurii","Sinha, Sanjiv","Fang, Kejie"]},{"key":"dc:creator","label":"Author","values":["Sohn, Donggyu Benjamin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020-08-27T00:51:29Z","2022-08-27T00:51:40Z","2020-05-08","2020-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"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":["Non-reciprocity","Integrated photonics"]}]},{"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 Donggyu Sohn"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/108329"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"Photonic integrated circuits (PICs) are a promising enabling technology for high bandwidth communications and sensors. Presently, all key optical components including lasers, waveguides, and modulators can be mass fabricated on a PIC using foundry-based manufacturing. However, essential non-reciprocal devices such as optical isolators and circulators are not yet available. Commercialized off-chip non-reciprocal systems are primarily based on Faraday rotation in magneto-optic materials. This approach is challenging to implement in integrated photonic systems due to several reasons; the required materials are not available in foundries; each operational wavelength band needs a different material; localization of magnetic field is difficult in PICs and can affect magnetically sensitive systems. One possible solution is the use of spatio-temporal modulation to produce non-reciprocal effect. For instance, a medium can be modulated by a traveling wave so that light propagating in opposite directions experience non-reciprocal frequency and momentum shifts. These \"\"momentum biased system'' do not require special magneto-optic materials and can be produced with common dielectrics that are already present in foundries. In this thesis, we extend this idea and experimentally demonstrate non-reciprocal light transmission using acousto-optic interaction in PICs. Co-fabricated electromechanical transducers are used to launch traveling acoustic waves that modulate integrated photonic components. We also show that the direction of non-reciprocity can be dynamically controlled by changing the acoustic wave direction. Using this approach, we demonstrate a reconfigurable non-reciprocal modulator that can be arranged in a multitude of reciprocal and non-reciprocal configurations by means of an external RF input. The methodology demonstrated in this thesis may enable new avenues for direction-dependent signal processing and optical isolation. Finally, I propose an important next step in the practical evolution of these devices -- a linear optical isolator -- that exhibits ideal characteristics of ultra-low forward loss and high contrast.\"","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01","The student, Donggyu Sohn, accepted the attached license on 2020-05-06 at 19:56.","The student, Donggyu Sohn, submitted this Dissertation for approval on 2020-05-06 at 20:01.","This Dissertation was approved for publication on 2020-05-08 at 14:04.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15260 on 2020-08-25 at 17:43:41","Made available in DSpace on 2020-08-27T00:51:29Z (GMT). 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Presently, all key optical components including lasers, waveguides, and modulators can be mass fabricated on a PIC using foundry-based manufacturing. However, essential non-reciprocal devices such as optical isolators and circulators are not yet available. Commercialized off-chip non-reciprocal systems are primarily based on Faraday rotation in magneto-optic materials. This approach is challenging to implement in integrated photonic systems due to several reasons; the required materials are not available in foundries; each operational wavelength band needs a different material; localization of magnetic field is difficult in PICs and can affect magnetically sensitive systems. One possible solution is the use of spatio-temporal modulation to produce non-reciprocal effect. For instance, a medium can be modulated by a traveling wave so that light propagating in opposite directions experience non-reciprocal frequency and momentum shifts. These \"\"momentum biased system'' do not require special magneto-optic materials and can be produced with common dielectrics that are already present in foundries. In this thesis, we extend this idea and experimentally demonstrate non-reciprocal light transmission using acousto-optic interaction in PICs. Co-fabricated electromechanical transducers are used to launch traveling acoustic waves that modulate integrated photonic components. We also show that the direction of non-reciprocity can be dynamically controlled by changing the acoustic wave direction. Using this approach, we demonstrate a reconfigurable non-reciprocal modulator that can be arranged in a multitude of reciprocal and non-reciprocal configurations by means of an external RF input. The methodology demonstrated in this thesis may enable new avenues for direction-dependent signal processing and optical isolation. Finally, I propose an important next step in the practical evolution of these devices -- a linear optical isolator -- that exhibits ideal characteristics of ultra-low forward loss and high contrast.\"","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01","The student, Donggyu Sohn, accepted the attached license on 2020-05-06 at 19:56.","The student, Donggyu Sohn, submitted this Dissertation for approval on 2020-05-06 at 20:01.","This Dissertation was approved for publication on 2020-05-08 at 14:04.","DSpace SAF Submission Ingestion Package generated from Vireo submission #15260 on 2020-08-25 at 17:43:41","Made available in DSpace on 2020-08-27T00:51:29Z (GMT). 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