The Design And Simulation Of The Low Loss Bend Detecting System Of Single Mode Fiber

Optical fiber communication has been developed at a rapid speed for more than40years. It provides an amazing transmission bandwidth for the communication network. Now, whether on land or at sea, optical network with a huge transmission capacity has spread all over the world and it provides a spacious, reliable transmission platform for the rapid growth of information stream. For a long time, optical fiber communication has been considered to be the most secure communication way. However, in1980’s, the foreign fiber tapping scandal was exposed by media, and the natural security barrier of optical fiber communication was no more existed from then on. At present, many countries have already been able to make use of some characteristics of optical fiber to intercept the information in transmission. America always plays a leading role in the technology of fiber tapping in the world, but it keeps the technical barrier to other countries all the time. In our country, although the research in this area started later, the development was quite fast. Now we have already grasped some techniques of fiber tapping and detection, but there is still a distance behind the foreign technology.Based on the technology of bent fiber leakage method, a set of fiber bend detection system which can be used for optical fiber leakage detection is designed. With single-mode optical fiber of G.652standard as the test conditions, the simulation of the system is carried out, which verifies the feasibility of the system and gives the key parameters for tapping. The main work and achievements are shown as follows:1. On the basis of deep understanding of the optical fiber tapping and detection development, the theory of various fiber taping and detection technology and their technical difficulties are analyzed. In the goal of easy-to-realize, low cost and high concealment, the basic optical path of bent fiber leakage method is designed.2. In view of the basic model of bent fiber leakage method, the technical difficulties of implementation is analyzed, and then the low insertion loss bend detection system of optical fiber is proposed. The key parameters and the influence factors of the system are given at the same time.3. Because of the complexity of the theoretical analysis, the bent waveguide equivalent refractive index model is used to design the simulation model of the bend detection system. The simulation is carried out with the help of the Rsoft software on the conditions of1550nm wavelength and G.652standard. The results have high reference value in the engineering.