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. These become particularly limiting in specialized fields like tissue engineering and bio-industrial processing, where unique pH probe. 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. A fabrication process, including sol–gel synthesis, optimisation of the.