Conventional two-mode fiber-optic strain sensors measure strain by inducing a path difference between the two propagating modes and spatially interfering the modal output pattern. At high strain values, the output mode pattern changes (rotates), limiting the range of measured strain. We have applied a mode separation/recombination technique and demonstrated it with a two-mode strain sensor, resulting in a rotationally invariant/stable output mode pattern and extended range of measured strain. The sensor was designed to measure strain, but with very little modification, it can measure temperature, pressure, electric and magnetic fields, etc. The improved rotationally invariant two-mode fiber-optic strain sensor performs to within 2% of standard electrical strain gauges.
© 2010 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: November 30, 2009
Revised Manuscript: March 15, 2010
Manuscript Accepted: March 17, 2010
Published: April 7, 2010
Sachin N. Dekate and Barry Grossman, "Rotationally insensitive circular-core two-mode fiber-optic strain sensor," Appl. Opt. 49, 2183-2189 (2010)