This review offers a comprehensive analysis of recent advances in optical fiber-based pH sensors, covering key techniques such as fluorescence-based, absorbance-based, evanescent wave, and interferometric methods. The apparatus is a straightforward modification of an existing phase fluorometer and exhibits accuracy and precision of approximately 0. Background: This study presents the development and characterisation of an optical fibre coated with silver nanoparticles and silica composite for pH measurement, where pH corresponds to the negative log of hydrogen ions in solution. Methods: A fabrication process, including sol–gel synthesis. While pH determination is a commonplace laboratory practice, conventional commercial pH probes exhibit drawbacks of bulkiness, slow response times, and signal drift.