title: Geometrical tuning art for entirely subwavelength grating waveguide based integrated photonics circuits.
abstract: Subwavelength grating (SWG) waveguide is an intriguing alternative to conventional optical waveguides due to the extra degree of freedom it offers in tuning a few important waveguide properties, such as dispersion and refractive index. Devices based on SWG waveguides have demonstrated impressive performances compared to conventional waveguides. However, the high loss of SWG waveguide bends jeopardizes their applications in integrated photonic circuits. In this work, we propose a geometrical tuning art, which realizes a pre-distorted refractive index profile in SWG waveguide bends. The pre-distorted refractive index profile can effectively reduce the mode mismatch and radiation loss simultaneously, thus significantly reduce the bend loss. This geometry tuning art has been numerically optimized and experimentally demonstrated in present study. Through such tuning, the average insertion loss of a 5 μm SWG waveguide bend is reduced drastically from 5.43 dB to 1.10 dB per 90° bend for quasi-TE polarization. In the future, the proposed scheme will be utilized to enhance performance of a wide range of SWG waveguide based photonics devices.
authors.affiliation: Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA.|Department of Electrical and Computer Engineering, The University of Texas at Austin, 10100 Burnet Rd., MER 160, Austin, Texas 78758, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Omega Optics, Inc., 8500 Shoal Creek Blvd., Bldg. 4, Suite 200, Austin, TX 78757, USA.
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Xu
authors.affiliation: Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA.|Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Donglei
authors.initials: D
authors.lastname: Fan
authors.affiliation: Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA.|Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Yaguo
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Omega Optics, Inc., 8500 Shoal Creek Blvd., Bldg. 4, Suite 200, Austin, TX 78757, USA.
authors.forename: Harish
authors.initials: H
authors.lastname: Subbaraman
authors.affiliation: Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, USA.|Department of Electrical and Computer Engineering, The University of Texas at Austin, 10100 Burnet Rd., MER 160, Austin, Texas 78758, USA.|Omega Optics, Inc., 8500 Shoal Creek Blvd., Bldg. 4, Suite 200, Austin, TX 78757, USA.
authors.forename: Ray T
authors.initials: RT
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D004867:Equipment Design; D018625:Microscopy, Atomic Force; D055095:Optics and Photonics / Q000295:instrumentation; D012825:Silicon / Q000737:chemistry
chemical_list: D012825:Silicon