Novel Ring Waveguide Device in a 2D Photonic Crystal Slab —Transmittance Simulated by Finit-Difference Time-Domain Analysis—

概要

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We propose a novel ring waveguide device in a two-dimensional (2D) photonic crystal (PhC) slab with a hexagonal lattice of air holes in a semiconductor (Si/GaAs). The device consists of a single line-defect ring waveguide and other parts. We simulated the propagation of a 1 ps pulse in the device. We analyzed the device using the 2D finite-difference time-domain (FDTD) method. The 1 ps pulse is transmitted well through sharp 60 degree bends in the ring waveguide. We designed and examined four-port directional couplers (DC) as input/output (I/O) components for the ring device. Coupling between the I/O waveguides and the ring waveguide in the device can be achieved by the four-port DC. We adopted a defect pattern formed with a straight waveguide and a waveguide with bends as the DC structure. This pattern realizes the coupling length based on the coupled mode theory. Our DC with the new multistep-like waveguides improved both the directivity and coupling factor across most of the frequency band where there are practical guided-wave modes in the photonic band gap (PBG). The propagation loss of a 1 ps pulse in the ring waveguide is low, so the transmission property of the ring device depends mainly on the I/O parts. In this study, we confirmed that the ring device would be sufficient for such applications as delay lines.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2004-04-15