Evanescent coupling between a side-polished single-mode optical fiber and a single-mode, pH-sensitive Langmuir–Blodgett overlay is used to demonstrate an intrinsic fiber-optic pH sensor. The sensor shows a wavelength sensitivity of 18.8 ± 0.8 nm/pH and a transmission sensitivity of 9.7 ± 0.8 dB/pH when operating at 750 nm.
© 1997 Optical Society of America
D. Flannery, S. W. James, R. P. Tatam, and G. J. Ashwell, "pH sensor using Langmuir–Blodgett overlays on polished optical fibers," Opt. Lett. 22, 567-569 (1997)