In this research, we develop an ammonia gas sensor using plastic optical fibers. These chemically etched optical fibers were layered with a thin film of carbon nanotubes to enhance the sensing capability of the developed sensor. The sensor was then interrogated with different ratios of gaseous ammonia to synthetic air using a controlled gas testing setup. The developed sensor exhibited high sensitivity of 12/Vol% of ammonia when tested with to various ratios of ammonia to air. The high response and recovery time of the sensor was calculated to be 25 and 23 seconds respectively makes it a promising contender in gas sensing applications.

Free space optical (FSO) networking has emerged as a promising technology for bridging the last mile gap in current high-rate fibre networks as well as for high-rate next-generation broadband wireless communication networks. This paper theoretically investigates the performance of the Free Space Optic system under rainy weather conditions using Optisystem software. Quality factor and eye-diagram analysis are used to analyse the FSO performance for several rain intensity and precipitation, following the Carbonneau model for rain attenuation . The results show that the link is completely lost when the distances are at 1.5 km, 1.2 km, and 0.8 km for light rain , moderate rain , and heavy rain , respectively. An optical amplifier is then introduced to improve the system performances and increase the signal intensity, which helps to mitigate the atmospheric effects easily. As a result, data transmission is sustained without interruptions, and overall connectivity is enhanced. Results show that the transmission range improves up to several meters, specifically under moderate rain weather condition when using the optical amplifier gain is applied.