Detection of Emanated Light at the Modified Clad Region (Sno2) of the Optical Fiber for Methanol Gas Sensing

A leakage detecting sensor (radiation mode (or) double fiber mode) is proposed to monitor the light rays propagates from the surface of the modified clad region (SnO2) of the optical fiber. The output intensity increases and decreases for the varying gas concentration (0-500 ppm) with the presence of different gases (methanol, ethanol, acetone and ammonia) at room temperature. The received output intensity from the clad modified surface increases for ammonia and methanol, whereas, it decreases for acetone and ethanol gases for the increase in the gas concentration. However, in the transmitting mode (single fiber mode) the output light intensity decreases for all the gases with varying gas concentration. The output gas sensitivity of the proposed sensor (double fiber mode) is compared with the transmitting mode sensor and the sensor shows superior response for methanol over other gases. The dynamic characteristics of the sensor are reported.