Weak Optical Signal Detection In Optical Fiber Sensor Networks

The optical fiber sensing network is widely used in our daily life,and plays an important role in the field of health inspection,aerospace,security and so on.But because of various types of sensor networks,complex,to maintain the high cost of detection,in particular,the cost of specialized testing equipment up to hundreds of thousands of,and the problems of complicated operation,the interface is not friendly,large,mobile measurement is not supported,single function,to the sensor network localization problem,troubleshooting lines brought many problems.Based on the above difficulties,this paper makes an in-depth study of the existing sensor networks,and studies the relevant theory and technical characteristics of the optical fiber sensing network.Focus on the optical signal receiving optical fiber sensor network detection,dedicated to research can produce photoelectric detector to detect weak signals,and the detector is easy to carry,easy to upgrade and expand the application,use and other peripheral equipment,reduce the cost of receiving and can ensure the reliability of detection.In order to improve the portability,scalability,combined with the widespread market of smart phones,the phone as a follow-up conversion of the display device,the detector with mobile phone as a portable instrumentation for the detection of weak signal in optical fiber sensor networks.The main contents and achievements of this paper are as follows:1?The design process is described in detail for the photoelectric detection module and the mobile phone with the specific contents include:the design principle of the detector,photoelectric detector and mobile phone interface circuit design,device selection,noise analysis,simulation,schematic and PCB design,welding circuit board,experimental verification.Innovative points:(1)The photodetector voltage signal detection conversion after the voltage/frequency(V/F)conversion of the output to the mobile phone,with mobile phone installed on the APP and its frequency conversion module for subsequent processing,and display the measurement results on the mobile phone screen.(2)In order to expand the scope of detection,the detection of weak optical signal is realized,and the function of automatic switch is added to the detector.Based on this thought,in the second chapter has designed a portable optical power meter can detect low frequency weak signal,it can be applied to the power test of optical fiber sensing network.2?In the optical fiber sensing system,dynamic signal detection using more.According to the characteristics of dynamic signals,the same is a combination of intelligent mobile phone as the receiving terminal,the design can be a dynamic detection signal detector design process includes principle analysis,simulation to determine the relevant parameters,the principle of interface circuit diagram and PCB design,the design of the interface circuit between photodetector and mobile phone,the welding debugging.After in-depth analysis of the relevant principles of optical cable identification system,the use of the detector,combined with the mobile phone made a portable optical fiber identification device,can be used in the optical cable in different lines of investigation.In addition,the principle of coherent detection and the structure of the system are analyzed in detail.