The critical findings associated with end-face total internal reflection (TIR) phenomemon we proved before are reported. In particular, these findings reveal that the end-face-TIR capable rays experience enormous mode mixing when encountering a roughened end face. As a result, 94% of the overall detectable power is contributed by this effect. With a smooth fiber end face, this figure is mere 52%. We interpret the mechanism behind these unusual phenomena and its significance for the performance enhancement of fiber optic evanescent wave sensor.
© 2011 Chinese Optics Letters
(060.2270) Fiber optics and optical communications : Fiber characterization
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(300.6280) Spectroscopy : Spectroscopy, fluorescence and luminescence
Jianjun Ma, Yasser Chiniforooshan, Huacai Chen, Jiahua Chen, Wojtek J. Bock, and Andrea Cusano, "Rerouting end-face-TIR capable rays to significantly increase evanescent wave signal power," Chin. Opt. Lett. 9, 040603- (2011)