Core depth determination of a slightly buried Si-wire waveguide with a reduced bend loss. (24th June 2021)

• Record Type: Journal Article
• Authors: Aso, Tatsuya; Ishiguro, Takehiro; Yamauchi, Junji; Nakano, Hisamatsu
• Is Part Of: Japanese journal of applied physics. Volume 60:Number 7(2021)
• Publication Date: 2021-06-24
• Subjects: Bend loss -- Bent optical waveguide -- FDTD method -- Imaginary-distance beam-propagation method -- Polarization crosstalk -- Si-wire waveguide; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/ac06b4
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: The effects of adjusting the distance between a core and an air-cladding interface on the propagation properties are investigated in a bent Si-wire waveguide. The eigenmode analysis is carried out using the imaginary-distance beam-propagation method based on Yee's mesh in the cylindrical co-ordinate system. The pure bend loss (PBL) is evaluated as a function of core depth for several core aspect ratios. Since a waveguide bend causes polarization coupling, the polarization crosstalk (PCT) is also evaluated by the propagation analysis with the aid of the FDTD method. It is found that a core depth with a minimized PBL exists for the TM mode when the air-cladding interface is placed at the position where the field amplitude decays to approximately 5% of its peak, with a PCT being less than −30 dB.