Posted May 16th, 2013
ALEXANDRIA, Va., April 23 -- United States Patent no. 8,428,400, issued on April 23, was assigned to Polytechnic Institute of New York University (Brooklyn, N.Y.).
"Fiber-optic extensometer" was invented by Nikhil Gupta (Ossining, N.Y.) and Nguyen Quang Nguyen (New York, N.Y.). According to the abstract* released by the U.S. Patent & Trademark Office: "An extensometer having a loop of a single-mode optical fiber. At least two points of the loop are attached to desired locations on a specimen. Light is transmitted through the loop and the transmitted optical power is measured by a photodetector. The deformation of the specimen causes the size and shape of the loop to change, which changes the transmitted optical power. The change in optical power is related to extension or compression using calibration curves. The sensor works on the principle of transmitted power modulation through the curved section." The patent was filed on Aug. 12, 2010, under Application No. 12/855,424.