Volatile organic compounds optical fiber gas sensor based on evanescentl field coupling and solvatochromism

We have developed an optical gas sensor for detection of volatile organic compounds (VOCs) gases. The side-polished optical fiber coupled with the polymer planar waveguide (PWG) which has high sensitive to change refractive index. The PWG was fabricated by coating the solvatochromic dye with a polyvinyl pyrrolidone (PVP). The fabricated gas sensor system was tested with five-types of VOCs gases. The different polarities of the VOC gases cause changes in the effective refractive index of the sensing membrane owing to evanescent field coupling. According to the results, the proposed gas sensor showed high sensitivity.