The Comb Filter Based On High Birefringence Fiber And Its Application In Fiber Laser

Fiber filter is of great interest for many applications, such as dense wavelength division multiplexing (DWDM) systems, optical fiber sensors and multi-wavelength fiber laser. Because the comb filter based on high birefringence fiber is a simple and effective configuration, it becomes the new focus to study this kind of the filter. In this thesis, we concentrate on the comb filter based on high birefringence fiber and several works are carried out as follow:In the first chapter, the background and significance of the fiber filter is introduced. Then, the development of fiber filter is summarized. At last of the chapter, the main contents of this paper are listed.In the second chapter, the principle of Sagnac loop filter and Solc filter is introduced. The transfer function of Sagnac loop filter and Solc filter based on high birefringence fiber is deduced using Jones matrix. The characteristics of the two filters are simulated in theory and proved in the experiment.In the third chapter, a two series connected Sagnac loop filter based on high birefringence fiber is designed. The transfer function is deduced using Jones matrix. The characteristics of filter are discussed by theory and experiment. Finally, the filter is used in the fiber laser, and stabled triple-wavelength and quadruple-wavelength can be obtained.In the fourth chapter, a comb filter with tunable wavelength spacing and switchable wavelength is designed by using fiber polarizer and high birefringence fiber. Firstly, the characteristics of the filter are analyzed in theory and experiment. Then, according to the analysis mentioned above, we find that the filter owns the function of tunable wavelength spacing and switchable wavelength. Besides this, the filter can also achieve flat-top bandpass. Finally, the filter is also used in fiber laser, multi-wavelength output with tunable wavelength spacing and switchable wavelength is obtained.