Lensed-taper launching coupler for small-bore, infrared hollow fibers

Yuji Matsuura, Hajime Hiraga, You Wang, Yuji Kato, Mitsunobu Miyagi, Shin Ichi Abe, Shinji Onodera

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


A new type of launching coupler for small-bore, hollow fibers, consisting of a lens and a tapered hollow waveguide, is proposed to increase the alignment tolerance between an input laser beam and small bore fibers. First, we designed the structural dimensions of the coupler by using a ray-tracing method. Then, a series of experiments employing tapered hollow waveguides made of Pyrex glass was performed to investigate the effectiveness of the new coupler. It is shown that the coupler has a high efficiency with attenuation of around 0.5 dB, especially when the inside of the taper section is coated with a polymer and silver film. In addition, we also show that the coupler has great tolerance for the transverse displacement of a waveguide axis, which gives a 0.1-dB loss increase for a 300-ॖm displacement.

Original languageEnglish
Pages (from-to)7818-7821
Number of pages4
JournalApplied optics
Issue number30
Publication statusPublished - 1997 Oct 20


  • Hollow waveguide
  • Infrared fiber optics
  • Infrared laser

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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