2026-09-22T03:13:53Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/108329 2023-07-11 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Bahl, Gaurav Bahl, Gaurav Vlasov, Yurii Sinha, Sanjiv Fang, Kejie Sohn, Donggyu Benjamin 2020-08-27T00:51:29Z 2020-08-27T00:51:29Z 2022-08-27T00:51:40Z 2020-05-08 2020-05 "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). No. of bitstreams: 2 SOHN-DISSERTATION-2020.pdf: 11697476 bytes, checksum: a7e5af5520a3363fbb0bc10752e886fb (MD5) LICENSE.txt: 4209 bytes, checksum: 8ec53cfcda678da2815551f08ef0e7fe (MD5) Previous issue date: 2020-05-08 Embargo set by: Seth Robbins for item 115944 Lift date: 2022-08-27T00:51:40Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Author requested closed access (OA after 2yrs) in Vireo ETD system Limited application/pdf http://hdl.handle.net/2142/108329 en Copyright 2020 Donggyu Sohn Non-reciprocity Integrated photonics Non-reciprocal light transmission in integrated photonic systems via acousto-optic interaction text Thesis Mechanical Sci & Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.