Reflectance-based no core fiber sensor with enhanced Sensitivity for salinity detection

An optical fiber sensor is fabricated and characterized in this communication for salinity detection. The proposed sensor consists of a multimode fiber (MMF) and a section of no core fiber (NCF) with a round tip. The sensor detects the intensity variation of the back reflected light caused by changing concentration of the salt solution surrounding the probe. The parameters of the sensor were studied for better performance. A down tapering is also introduced to enhance the sensitivity of the sensor and a high sensitivity of 0.773 dB/% is obtained for a salinity range of 0-20%. Due to its high sensitivity, low cost and compact size, the proposed sensor can be very much useful in water quality monitoring for environmental, healthcare and industrial applications.