Optimization of Coupling Condition in Distance Between the Sphere and the Tapered Fiber for Diameter Measurement of Microsphere by Using WGM Resonance

  • Atsushi AdachiEmail author
  • Masaki Michihata
  • Terutake Hayashi
  • Yasuhiro Takaya
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 306)


In this study, it was proposed that whispering gallery mode (WGM) resonances was applied for diameter measurement of microsphere. WGM resonances were excited in a microsphere by introducing light through tapered fiber that thinned optical fiber to a few micrometers. Resonance wavelengths could be measured by monitoring intensity of the transmitted light of tapered fiber, since the light is strongly coupled to the microsphere at the resonance wavelengths. Therefore it is important to address the coupling conditions in order to measure WGM resonances accurately. Thus, optimization of the coupling is key issue to determine the diameter of a microsphere. Numerical analysis was implemented to estimate the coupling coefficients of each modes of WGM. Then the coupling was conducted experimentally as parameter was distance between the sphere and the tapered fiber.


WGM resonance Diameter measurement Tapered fiber CMM probe 



This work was financially supported by JSPS Grant-in-aid for challenging exploratory research (No. 24656102) and also Mitutoyo association for science and technology (MAST).


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Atsushi Adachi
    • 1
    Email author
  • Masaki Michihata
    • 1
  • Terutake Hayashi
    • 1
  • Yasuhiro Takaya
    • 1
  1. 1.Department of Mechanical EngineeringOsaka UniversityOsakaJapan

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