Highly efficient optical add-drop filter with an angle-polished fiber coupler

作     者：Dong, Royce Fan, Zheng Liao, Jie Qavi, Abraham Long, Gui-Lu Yang, Lan 

作者机构：Department of Electrical & Systems Engineering Washington University in St. Louis St. LouisMO63130 United States Department of Physics Washington University in St. Louis St. LouisMO63130 United States Department of Pathology & Immunology Washington University School of Medicine St. LouisMO63110 United States State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua University Beijing100084 China Tsinghua National Laboratory for Information Science and Technology Beijing100084 China Collaborative Innovation Center of Quantum Matter Beijing100084 China 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2019年

核心收录：

主　　题：Degrees of freedom (mechanics) 

摘      要：Microbubble whispering-gallery resonators have shown great promise in fiber-optic communications because of their low confinement loss and hollow cores, which allow for facile stress-based tunability. Usually, the transmission spectrum of taper-coupled microbubbles contains closely spaced modes due to the relatively large radii and oblate geometry of microbubbles. In this letter, we develop an optical add-drop filter using a microbubble coupled to fiber taper and angle-polished fiber waveguides. Because of the extra degree of freedom in the angle of its polish surface, the angle-polished fiber can be used for the discriminatory excitation of certain radial-order modes in the optical microcavity, reducing the high modal density and enhancing add-drop selectivity. Our robust and tunable add-drop filter demonstrated a drop efficiency of 85.9% and quality factor of 2 x 107, corresponding to a linewidth of 9.68 MHz. As a proof of concept, the drop frequency was tuned using internal aerostatic pressure at a rate of 7.3 ± 0.2 GHz/bar with no diminishing effects on the add-drop filter performance. Copyright © 2019, The Authors. All rights reserved.