Tilted fiber Bragg grating pH sensor based on polyaniline reaction deposition film layer

In this paper, we propose a tilted fiber Bragg grating (TFBG) pH sensor based on polyaniline (PANI) reactive deposition film. The micron-scale thickness polyaniline film provides the sensor with good sensitivity, and it achieves measurement of pH values ranging from 2 to 12 by utilizing the pH-responsive mechanism of PANI and the refractive index characteristics of TFBG. Experimental results show that within the 2–12 pH range, the sensitivity of the TFBG surface plasmon resonance pH sensor based on PANI coating is − 0.03815, and results demonstrate, a linear correlation coefficient between wavelength and pH value reaching 0.98719. This indicates significant potential for future engineering applications in real-world pH measurement using this sensor.