Research of the measuring technique of numerical aperture of optical fiber using near infrared light.

In this paper, we demonstrate a new technology in which we use the near infrared (NIR) electro-optical device and projection method to measure the numerical aperture (NA) of NIR fiber. Using the optical coupler to let the NIR light enter into an optical fiber, the projection pattern is then measured at the distance of L, where the length L and the diameter W of the projection pattern area on screen is recorded. The NA of NIR fiber is computed from the recorded data. This is a fast method for testing NA and can measure the NA deviation to an accuracy of 0.01. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 582–584, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23161 [ABSTRACT FROM AUTHOR]