Research On Fiber Optical Gas Sensor Based On Tunable Fabry-Perot Cavity

Optical fiber gas sensing technology is a developing and novel technique,which has a wide applicable prospect in industrial production,environment monitoring and medical science.In recent years,with the development of optical fiber sensing technology,the research of optical fiber gas sensor has been seriously regarded all over the world.The signal detected by optical fiber gas sensors is carried by light wave,which has no influence on the measured object.The sensor that has good independence performance itself can be adapted to all kinds of surroundings.The optical fiber sensing system with the sensors,which can be connected with computers conveniently,can realize many functions request and intellectualized need.They can match with remote measure technology to measure and control in long distance.In this paper,we have studied spectrum absorptive optical fiber gas sensors.Each kind of gases has inherent absorptive spectrum.When a light source's emitted wavelength is corresponding to the gas's absorptive wavelength,resonating absorption will happen.And the resonating intensity is related to the gas's concentration.The gas's concentration can be known by the detection of light absorptive intensity.In this paper,the research status about spectrum absorptive optical fiber gas sensors at home and abroad was studied and analyzed.Different methods had their own advantages and disadvantages.Novel experiment schemes were designed to improve the precision and applicability of gas sensors.Through analyzing the gas's absorptive spectrum and the existing light sources on the market,two experiment systerms of Optical Fiber Gas Sensor Based on Tunable Fabry-Perot Cavity were provided.The first system is broadband LED light source,because light power is smaller through Tunable Fabry-Perot Cavity,the measurement accuracy is reduced;The second system is tunable laser light source based on semiconductor optical amplifier(SOA),light output power and signal-to-noise ratio are improved effectively;The two systerms are based on unable Fabry-Perot Cavity and the wavelength range of light sources are broad,so they can be used to detect several kinds of gases.Experimental research was done based on these two systerms.Take the example of acetylene;the response curve of acetylene gas was plotted.Comparing several algorithm,we found out the most appropriate algorithm for the two systerms of Optical Fiber Gas Sensor.In contrast with the experimental systerm based on LED light source,the systerm based on semiconductor optical amplifier(SOA) has high measurement accuracy but it's stability is poor.The work of this subject has Played a solid foundation and Provided a valuable reference for the research of high-Performance Optical Fiber Gas Sensor in the future.