Ultracompact optical switch using a single semisymmetric Fano nanobeam cavity
Ziwei Cheng, Jianji Dong, Xinliang Zhang
Abstract
We propose and theoretically analyze a generalized four-port waveguide-cavity system with a novel, to the best of our knowledge, semisymmetric Fano structure. By applying the system to a silicon-based photonic crystal nanobeam cavity (PCNC), we experimentally demonstrate an ultracompact crossbar optical switch with high drop port transmission. A low insertion loss of 1.5 dB in the drop port at the cross state is achieved comparing to the 8.5 dB insertion loss in a traditional non-Fano structure. The device is also benefited by the high quality factor and small mode volume for efficient switching and the ultracompact footprint of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>14</mml:mn> <mml:mspace width="thickmathspace"/> <mml:mtext>µ</mml:mtext> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> in the core structure. The proposed PCNC switch shows great potential in various optical systems on chip to increase the integration and reduce energy consumption.