Compact optical circulator based on a uniformly magnetized ring cavity

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• 作者：Wojciech ?migaj^a ; ^{wojciech.smigaj@institutoptique.fr} ; Liubov Magdenko^b ; ¹ ; Javier Romero-Vivas^a ; ² ; Sé ; bastien Guenneau^a ; Bé ; atrice Dagens^b ; Boris Gralak^a ; Mathias Vanwolleghem^b
• 关键词：Magneto-optics ; Integrated optics ; Circulators ; Resonant cavities ; Fano resonances ; Coupled-mode theory
• 刊名：Photonics and Nanostructures - Fundamentals and Applications
• 出版年：2012
• 出版时间：January 2012
• 年：2012
• 卷：10
• 期：1
• 页码：83-101
• 全文大小：1429 K

文摘

We propose a new class of compact integrated optical circulators providing a large isolation level while maintaining a straightforward technological feasibility. Their layout is based on a nonreciprocal radial Bragg cavity composed of concentric magneto-optical rings. The circulator ports are standard rib waveguides, butt-coupled to the cavity by cutting through its outer rings. The device is specifically designed for operation in a uniform external magnetic field. Using a coupled-mode description of the complete cavity/waveguide-port system, we explore the rich behaviour of cavity circulators in presence of varying levels of direct port-to-port coupling. We demonstrate numerically a strongly miniaturized two-dimensional cavity circulator, with a total footprint of less than (10¦Ë)², achieving a 20-dB isolation level at telecom frequencies over a bandwidth of 130 GHz. The device is found to be very tolerant with respect to fabrication imperfections. We finish with an outlook on three-dimensional versions of the proposed nonreciprocal cavities.