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Fiber taper characterization by optical backscattering reflectometry

Lai, Yu-Hung and Yang, Ki Youl and Suh, Myoung-Gyun and Vahala, Kerry J. (2017) Fiber taper characterization by optical backscattering reflectometry. Optics Express, 25 (19). pp. 22312-22327. ISSN 1094-4087. doi:10.1364/OE.25.022312.

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Fiber tapers provide a way to rapidly measure the spectra of many types of optical microcavities. Proper fabrication of the taper ensures that its width varies sufficiently slowly (adiabatically) along the length of the taper so as to maintain single spatial mode propagation. This is usually accomplished by monitoring the spectral transmission through the taper. In addition to this characterization method it is also helpful to know the taper width versus length. By developing a model of optical backscattering within the fiber taper, it is possible to use backscatter measurements to characterize the taper width versus length. The model uses the concept of a local taper numerical aperture to accurately account for varying backscatter collection along the length of the taper. In addition to taper profile information, the backscatter reflectometry method delineates locations along the taper where fluctuations in fiber core refractive index, cladding refractive index, and taper surface roughness each provide the dominant source of backscattering. Rayleigh backscattering coefficients are also extracted by fitting the data with the model and are consistent with the fiber manufacturer’s datasheet. The optical backscattering reflectometer is also used to observe defects resulting from microcracks and surface contamination. All of this information can be obtained before the taper is removed from its fabrication apparatus. The backscattering method should also be prove useful for characterization of nanofibers.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lai, Yu-Hung0000-0002-9639-6569
Yang, Ki Youl0000-0002-0587-3201
Suh, Myoung-Gyun0000-0002-9527-0585
Vahala, Kerry J.0000-0003-1783-1380
Additional Information:© 2017 Optical Society of America. Received 13 Jul 2017; revised 23 Aug 2017; accepted 29 Aug 2017; published 5 Sep 2017. We thank Dr. Hsieh-Chen Tsai and Dr. Albert Chern at Caltech for their helpful discussions and comments on this work. Funding: Defense Advanced Research Projects Agency (DARPA) (W31P4Q-14-1-0001, 70NANB11H130); National Science Foundation (NSF) (1125565).
Group:Institute for Quantum Information and Matter
Funding AgencyGrant Number
Defense Advanced Research Projects Agency (DARPA)W31P4Q-14-1-0001
Defense Advanced Research Projects Agency (DARPA)70NANB11H130
Issue or Number:19
Classification Code:OCIS codes: (060.2270) Fiber characterization; (140.3945) Microcavities; (290.1350) Backscattering
Record Number:CaltechAUTHORS:20171012-143819083
Persistent URL:
Official Citation:Yu-Hung Lai, Ki Youl Yang, Myoung-Gyun Suh, and Kerry J. Vahala, "Fiber taper characterization by optical backscattering reflectometry," Opt. Express 25, 22312-22327 (2017)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82324
Deposited By: Tony Diaz
Deposited On:12 Oct 2017 22:00
Last Modified:15 Nov 2021 19:49

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