Temperature-insensitive and intensity-modulated embedded photonic-crystal-fiber modal-interferometer-based microdisplacement sensor

We propose and demonstrate a temperature-insensitive and intensity-modulated embedded photonic-crystal-fiber (PCF) modal-interferometer-based microdisplacement sensor. The embedded PCF sensor has the structure of single-mode-fiber (SMF)-PCF-SMF, with a core offset at one splice joint. With the structure embedded in a cured carbon-fiber-composite-laminate-based simple-supported beam, the applied microdisplacement can be measured by monitoring its extinction ratio variation, while the extinction ratio variation is independent of the temperature variation and bending-induced strain. The sensitivity reaches 0.0024 dB/mu m, the measurement resolution reaches 42 mu m, and the dynamic measurement range is within the range of 0-200 Hz. (C) 2011 Optical Society of America