Design of LCoS devices using high contrast gratings

Thandasseril, Sangeeth Soman

Design of LCoS devices using high contrast gratings

Thandasseril, Sangeeth Soman

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Publication Type:: Thesis
Issue Date:: 2022

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Field	Value	Language
dc.contributor.author	Thandasseril, Sangeeth Soman
dc.date.accessioned	2023-03-28T22:08:59Z
dc.date.available	2023-03-28T22:08:59Z
dc.date.issued	2022
dc.identifier.uri	http://hdl.handle.net/10453/168767
dc.description	University of Technology Sydney. Faculty of Science.	en_US.UTF-8
dc.description.abstract	Liquid crystal on silicon (LCoS) technology, existing for more than four decades ago, is facilitating a range of applications in photonics. For example, phase-only LCoS devices (LCoSDs) are now routinely used as switching elements in wavelength-selective switches. A range of different approaches have been considered to improve the performance of conventional LCoSDs. For instance, the diffractive optical losses associated with the pixelated backplane need to be alleviated to enhance the optical performance of LCoSDs. To make the device optically flat, I am using the high- contrast grating (HCG) structures implemented by Finisar Australia Pty Limited in C-Band and optimising the performance in other wavelength regions of operation. In this thesis, I have numerically investigated HCGs to enhance the performance of LCoSDs. The study was performed using Finite-difference time-domain (FDTD) and rigorous coupled-wave analysis (RCWA) methods. For each significant spectral range (1064 nm, visible range, C-band), HCG parameters have been optimised separately. According to this research, silicon would be a suitable material for near-infrared gratings, while silicon nitride would be a promising material for visible gratings. Furthermore, I have investigated a crosslinked silicon HCG structure to improve the reflectivity of conventional LCoS in the C-Band wavelength range and around 1064 nm, introducing polarisation-independent reflectivity. Finally, I studied Finisar's polarisation-independent LCoSD and optimised the performance using various optimisation techniques. In the future, the results of this research will likely contribute to the design of high-performance wavelength selective switches and WaveShapers.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/168767/2/02whole.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2022 Sangeeth Soman Thandasseril
dc.rights	au.edu.uts.lib/ppc
dc.title	Design of LCoS devices using high contrast gratings	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Liquid crystal on silicon (LCoS) technology, existing for more than four decades ago, is facilitating a range of applications in photonics. For example, phase-only LCoS devices (LCoSDs) are now routinely used as switching elements in wavelength-selective switches. A range of different approaches have been considered to improve the performance of conventional LCoSDs. For instance, the diffractive optical losses associated with the pixelated backplane need to be alleviated to enhance the optical performance of LCoSDs. To make the device optically flat, I am using the high- contrast grating (HCG) structures implemented by Finisar Australia Pty Limited in C-Band and optimising the performance in other wavelength regions of operation. In this thesis, I have numerically investigated HCGs to enhance the performance of LCoSDs. The study was performed using Finite-difference time-domain (FDTD) and rigorous coupled-wave analysis (RCWA) methods. For each significant spectral range (1064 nm, visible range, C-band), HCG parameters have been optimised separately. According to this research, silicon would be a suitable material for near-infrared gratings, while silicon nitride would be a promising material for visible gratings. Furthermore, I have investigated a crosslinked silicon HCG structure to improve the reflectivity of conventional LCoS in the C-Band wavelength range and around 1064 nm, introducing polarisation-independent reflectivity. Finally, I studied Finisar's polarisation-independent LCoSD and optimised the performance using various optimisation techniques. In the future, the results of this research will likely contribute to the design of high-performance wavelength selective switches and WaveShapers.

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http://hdl.handle.net/10453/168767