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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 20 — Sep. 26, 2011
  • pp: 18910–18916

A terahertz broadband 3dB directional coupler based on bridged PPDW

Longfang Ye, Yong Zhang, Ruimin Xu, and Weigan Lin  »View Author Affiliations

Optics Express, Vol. 19, Issue 20, pp. 18910-18916 (2011)

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In this paper, a novel broadband 3dB directional coupler with very flat coupling based on bridged parallel plate dielectric waveguide (PPDW) is proposed and demonstrated. In the uniform coupling section, a bridge structure between the two PPDWs is employed to obtain accurate coupling value and achieve a broadband coupling. It is found that this new type of coupling structure exhibits excellent performance at terahertz frequencies. In order to achieve strong isolation between the adjacent ports and reduce the power reflection in all ports, two quarter-circle bend arms are introduced as the curved transition sections to connect the uniform coupling section. For this bridged coupler, it only needs the value of the uniform coupling length as short as 400μm to achieve a broadband 3dB coupling. In this case, the coupler’s average return loss is greater than 28dB, average isolation is better than 27dB and average coupler loss is only 0.9dB, over a percentage bandwidth of 12.5% at 1THz. Compared to the conventional PPDW coupler, the bridged PPDW coupler shows significantly greater bandwidth (about 4.2 times), compact and mechanically stable with a much shorter uniform coupling length (reduced about 61%), which may have potential applications for terahertz integrated circuits and systems.

© 2011 OSA

OCIS Codes
(060.1810) Fiber optics and optical communications : Buffers, couplers, routers, switches, and multiplexers
(130.3120) Integrated optics : Integrated optics devices
(040.2235) Detectors : Far infrared or terahertz

ToC Category:
Integrated Optics

Original Manuscript: July 11, 2011
Revised Manuscript: August 24, 2011
Manuscript Accepted: August 26, 2011
Published: September 14, 2011

Longfang Ye, Yong Zhang, Ruimin Xu, and Weigan Lin, "A terahertz broadband 3dB directional coupler based on bridged PPDW," Opt. Express 19, 18910-18916 (2011)

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