Fiber optic sensor is proposed based on cladding modification method for detecting ammonia emissions. Nanocrystalline titanium dioxide is used as a sensing material and spectral characteristics of the
sensor are studied for different concentrations (50-500 ppm) of ammonia, methanol and ethanol. The sensor
shows a linear variation in the output light intensity with the concentration. The light intensity increases for
ammonia whereas it decreases for methanol and ethanol. Gas selectivity of the sensor is discussed.
A fiber optic sensor for measuring thickness of transparent plates (1 to 2.5 mm) is proposed based on reflective type
displacement fiber optic sensor. The peak position in the output of the receiving fiber, which various linearly, is related
to the thickness of the transparent plate. Theoretical model is proposed and compared with the experimental results. The
output characteristics of the sensor are studied in terms of fiber optic parameters such as numerical aperture and