Research On The Characteristics Of High-birefringence Fiber Sagnac Filter

The maturation of DWDM(Dense Wavelength Division Multiplexing) has greatly improved the capacity of optical communication system and become the mainly technology to increase the capacity of optical transmission network. In DWDM, with the increasing of the channel density, optical filters become a hot research area in optical fiber communication. One of these filters is called Sagnac filter based on High-Birefringence fiber (HBF) which is bearing many attractive features, such as polarization independence, simple structure, flexible operation, tunable and attracted widespread attention in recent years.In this thesis, the characteristics of HBF Sagnac filter are studied based on Jones matrix, based on which a large amount of numerical simulations and experimental researches has been taken. Two HBF Sagnac cascade filters are designed and analysed using numerical simulation.The major works are summarized as follows:1. First, based on the Jones matrix theory, strict theoretical analysis is taken on the reflection and transmission characteristics of HiBi fiber Sagnac filter, which contains single high birefringence fiber, and MATLAB simulation is taken to discuss the effect of the parameters of polarization controller, the coupling ratio, the length and birefringence of the HiBi fiber to the characteristics of HiBi fiber Sagnac filter.2. The transfer functions of multi-section HiBi fiber Solc-Sagnac filter and Loyt-Sagnac filter are deduced theoretically, the output spectral is studied through data simulation.3. Two new Sagnac loop filter are designed and analyzed. These loop filters are composed of multi-section Solc-Sagnac filters and multi-section Loyt-Sagnac filters. They show many filtering functions, and can be applied in a wide range of fields, such as polarization independence, flexible regulation, tunable, etc.The result of the research of the paper show that the HBF Sagnac filter will be found many potential applications in the fields of fiber sensor, tunable fiber lasers, and DWDM system in the future.