A method of stretching optical fiber holds interest for measuring strain in smart structures where the physical displacement may be used to tune optical fiber lasers. A small, lightweight, tunable fiber laser is ideal for demodulating strain in optical fiber Bragg gratings (FBGs) attached to smart structures such as the reusable launch vehicle that is being developed by NASA. A method is presented for stretching optical fibers using the thin-layer composite unimorph ferroelectric driver and sensor (THUNDER) piezoelectric actuators invented at NASA Langley Research Center. THUNDER actuators use a piezoelectric layer bonded to a metal backing to enable the actuators to produce displacements larger than the unbonded piezoelectric material. The shift in reflected optical wavelength resulting from stretching the FBG is presented. Means of adapting THUNDER actuators for stretching optical fibers are discussed, including ferrules, ferrule clamp blocks, and plastic hinges made with stereo lithography.

Date Published: 1 October 2002
PDF: 8 pages
Opt. Eng. 41(10) doi: 10.1117/1.1504723
Published in: Optical Engineering Volume 41, Issue 10