Optical isolators are unidirectional devices that employ the magneto-optical (MO) property of iron garnets to block the reflected light in almost all optical systems. Sputter deposition of either doped yttrium iron garnets (YIG) with seed-layers or seed-layer free terbium iron garnets (TIG) will help realize integrated planar isolators. Faraday rotation waveguides are designed as a viable solution to enable these monolithically integrated garnets to overcome the limitations inherent to hybrid integration of interferometric devices. In fact, small footprint Faraday rotation devices have been achieved using doped TIG for both TE/TM modes with sufficiently low loss and large isolation ratios.
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The authors would like to acknowledge Dr. David C. Hutchings, Dr. Cui Zhang, Dr. Sang-Yeob Sung, Dr. Andrew D. Block, Dr. Prabesh Dulal and Thomas E. Gage for their contributions to the research works highlighted in this article. Parts of this work were carried out in the Characterization Facility and the Minnesota Nano Center, University of Minnesota, which receives partial support from NSF through the MRSEC and NNCI programs respectively.
© 2018 Optical Society of America.