A method of measuring strain over 30-cm intervals to an accuracy of10 microstrain in unaltered low-loss communications-grade single-modeoptical fiber is presented. The method uses a tunable external cavity diode laser to measure the reflected intensity of a reflector–fiber system as a function of wavelength. This measurement is performed with no strain applied to the fiber to produce a reference and then again after a strain has been induced. Cross correlation of the Rayleigh scatter spectra from a selected section of fiber in the strained and unstrained states determines the spectral shift resulting from the applied strain.
© 1998 Optical Society of America
(060.2300) Fiber optics and optical communications : Fiber measurements
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(060.2430) Fiber optics and optical communications : Fibers, single-mode
(060.2920) Fiber optics and optical communications : Homodyning
(290.5870) Scattering : Scattering, Rayleigh
Mark Froggatt and Jason Moore, "High-Spatial-Resolution Distributed Strain Measurement in Optical Fiber with Rayleigh Scatter," Appl. Opt. 37, 1735-1740 (1998)