• Title/Summary/Keyword: Normalized delay-bandwidth product

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Wideband Slow Light in a Line-defect Annular Photonic-crystal Waveguide

  • Kuang, Feng;Li, Feng;Yang, Zhihong;Wu, Hong
    • Current Optics and Photonics
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    • v.3 no.5
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    • pp.438-444
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    • 2019
  • In this theoretical study, a line-defect photonic-crystal waveguide hosted in an annular photonic crystal was demonstrated to provide high-performance slow light with a wide band, low group-velocity dispersion, and a large normalized delay-bandwidth product. Combined with structural-parameter optimization and selective optofluid injection, the normalized delay-bandwidth product could be enhanced to a large value of 0.502 with a wide bandwidth of 58.4 nm in the optical-communication window, for a silicon-on-insulator structure. In addition, the group-velocity dispersion is on the order of $10^5$ ($ps^2/km$) in the slow-light region, which could be neglected while keeping the signal transmission unchanged.

Tunable Slow Light with Large Bandwidth and Low-dispersion in Photonic Crystal Waveguide Infiltrated with Magnetic Fluids

  • Lei, Weizheng;Pu, Shengli
    • Journal of Magnetics
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    • v.20 no.2
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    • pp.110-113
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    • 2015
  • Two kinds of magnetic fluids with different volume fractions are symmetrically filled into the W0.9 photonic crystal waveguide structure. The 2D plane-wave expansion method is used to investigate the slow light properties numerically. The constant group index criterion is employed to evaluate the slow light performance. The wavelength bandwidth ${\Delta}{\lambda}$ centering at ${\lambda}_0=1550nm$ varies from 32.4 to 44.2 nm when the magnetic field factor ${\alpha}_{\parallel}$ changes from 0 to 1. And the corresponding normalized delay bandwidth product can be tuned from 0.221 to 0.258. For comparison and optimization, two infiltration cases are investigated and the more advantageous infiltration scheme is found.