Synthesis and Analysis of Planar Optical Waveguides as pH Sensors

Objective and Method: In this paper, dye is used as pH sensors. We here report the study of the effect of pH solutions on Methyl red doped polystyrene and Bromocresol Purple doped Styrene acrylonitrile waveguides. The effect of pH solutions was observed on the absorption spectra and output intensity of the waveguides. Conclusion: It was observed that for pH solutions to which the dye is sensitive, output intensity decreased and it was clearly seen in absorption spectra too. Methyl red doped polystyrene waveguides showed sensitivity for pH range 5-6 and Bromocresol purple doped Styrene acrylonitrile waveguides showed sensitivity for pH range 5-9. These dye-doped polymer waveguides can be used as pH sensors.