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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 22 — Oct. 24, 2011
  • pp: 21588–21594

Mode-size converter with high coupling efficiency and broad bandwidth

Qing Fang, Junfeng Song, Xianshu Luo, Mingbin Yu, Guoqiang Lo, and Yuliang Liu  »View Author Affiliations

Optics Express, Vol. 19, Issue 22, pp. 21588-21594 (2011)

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An ultralow coupling loss and broad bandwidth fiber-to-waveguide mode-size converter is demonstrated for nano-scale waveguides on SOI platform using CMOS technology in this paper. The mode-size converter consists of a cantilevered PECVD SiO2 waveguide and a-Si nano-tapers by removing the adjacent SiO2 layer and underlying substrate Si. The a-Si waveguide is located at the center of the cantilevered SiO2 waveguide. We characterized the cantilevered mode-size converter using cleaved optical single mode fiber with 10.5 µm mode field diameter. With refractive index (1.375) matching oil, the measured coupling efficiencies between the cleaved optical fiber and this converter are higher than 80% per facet and 70% per facet for TE and TM modes at 1600 nm, respectively. The polarization dependent loss and the coupling loss variation of this converter are less than 1.0 dB at the wavelength range of 1520 ~1640 nm. The 1-dB bandwidths for both TE and TM modes are more than 120 nm. The alignment tolerances for TE and TM modes are ± 2.8 µm and ± 2.1 µm at 1-dB excess loss in horizontal direction and vertical direction, respectively.

© 2011 OSA

OCIS Codes
(130.0250) Integrated optics : Optoelectronics
(130.2790) Integrated optics : Guided waves
(130.3120) Integrated optics : Integrated optics devices

ToC Category:
Integrated Optics

Original Manuscript: August 15, 2011
Revised Manuscript: September 20, 2011
Manuscript Accepted: September 22, 2011
Published: October 18, 2011

Qing Fang, Junfeng Song, Xianshu Luo, Mingbin Yu, Guoqiang Lo, and Yuliang Liu, "Mode-size converter with high coupling efficiency and broad bandwidth," Opt. Express 19, 21588-21594 (2011)

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