On-chip beam rotators, adiabatic mode converters, and waveplates through low-loss waveguides with variable cross-sections oleh Bangshan Sun, Fyodor Morozko, Patrick S. Salter, Simon Moser, Zhikai Pong, Raj B. Patel, Ian A. Walmsley, Mohan Wang, Adir Hazan, Nicolas Barré, Alexander Jesacher, Julian Fells, Chao He, Aviad Katiyi, Zhen-Nan Tian, Alina Karabchevsky, Martin J. Booth