Sputter-deposited magneto-optical garnet thin films for all-mode Faraday rotators

Stadler, B. J.H. and Hutchings, D. (2018) Sputter-deposited magneto-optical garnet thin films for all-mode Faraday rotators. MRS Bulletin, 43(6), pp. 430-435. (doi: 10.1557/mrs.2018.121)

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Faraday rotators in optical isolators, typically composed of iron garnets, are photonic analogues of electrical diodes in that they do not allow reciprocal transmission of light. Isolators are especially important for blocking back-reflected light from reaching source lasers, as such feedback gives rise to unwanted noise and instabilities. In commonly implemented photonic integrated circuits (PICs), isolation is the only critical function that cannot yet be achieved by direct integration. While several techniques have been explored for integrating high-gyrotropy garnets into silicon-on-insulator PICs, this article focuses on sputter deposition, which is the most up-scalable process. High-gyrotropy Ce-doped yttrium iron garnet on nongarnet substrates can be made by sputter deposition with the use of garnet seed layers. Because these seed layers can compromise device performance, seed layer-free terbium iron garnet (TIG) has also recently been developed. Careful doping of TIG can produce Faraday rotations with opposite chiralities, which enable new device designs. Most optical isolator designs involve two-dimensional transverse magnetic-mode structures, such as interferometers or ring resonators, which employ nonreciprocal phase shift. One-dimensional Faraday rotation waveguides with quasi-phase matching have been shown to enable direct integration of isolators for all modes, including the transverse electric mode of lasers currently available for fully integrated PICs.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Hutchings, Professor David
Authors: Stadler, B. J.H., and Hutchings, D.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:MRS Bulletin
Publisher:Cambridge University Press
ISSN (Online):1938-1425
Published Online:11 June 2018
Copyright Holders:Copyright © 2018 Materials Research Society
First Published:First published in MRS Bulletin 43(6):430-435
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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