A Poly(vinyl alcohol) Coating Method for a Tilted‐Fiber Bragg‐Grating‐Assisted Fiber Hygrometer.

A new technique of depositing a poly(vinyl alcohol) (PVA) coating with an airbrush on the cylindrical surface of an optical fiber with real‐time spectral monitoring is presented. The method is applied for creating hygroscopic PVA coating as a part of the tilted‐fiber Bragg‐grating (TFBG)‐assisted fiber hygrometer samples. By monitoring the transmission spectra of the samples placed in a climatic chamber with variable relative humidity, the performance of the resulting coating is evaluated. Experimental data are presented, demonstrating the effectiveness of the described technique for humidity‐sensing purposes. [ABSTRACT FROM AUTHOR]