Study On All-Fiber Comb Filter And Mach-zehnder Interferometer

All optical network is the development trend of the communication network, and attracts a lot of attention. All-fiber comb filters and Mach-Zehnder interferometers are becoming key components in all optical network for their excellent performances. Under the supports of the Major State Basic Research Development Program of China (No.2010CB328206), the National High Technology Research and Development Program of China (No.2008AA01Z215), and the Key Program of the National Natural Science Foundation of China (No.60837002), the fiber comb filter using a twin-core fiber and the fiber Mach-Zehnder interferometer using an eccentric core single-mode fiber have been deeply studied, and the main achievements are listed as follows:1. The main parameters of the fiber comb filter based on a twin-core fiber coupler and the fiber comb filter based on a twin-core fiber Mach-Zehnder interferometer, and their influences on the performances of the devices have been theoretically analyzed. The fiber comb filter based on a twin-core fiber coupler with an uniform free spectral range and the fiber comb filter based on a twin-core fiber Mach-Zehnder interferometer with flat passband have been discussed. The comb filter using a twin-core fiber meeting the advices of ITU-T has been fabricated experimentally. The refractive index change of fiber caused by the CO2laser irradiation has been analyzed, and according to this the CO2laser has been used to adjust the central wavelength of the comb filter.2. A twin-core fiber with the cross section similar to a dumbbell has been proposed and fabricated experimentally. The splicing techniques of the twin-core fiber and the single-mode fiber, and two twin-core fibers have been studied experimentally by using this twin-core fiber. The splicing loss below1dB between the twin-core fiber and the single-mode fiber, and the splicing loss below1.5dB between two twin-core fibers have been experimentally obtained.3. An in-line all fiber Mach-Zehnder interferometer using an eccentric core single-mode fiber has been proposed and analyzed. The eccentric core single-mode fiber has been fabricated experimentally by using fiber preform goniometric-groove method and stack-and-draw method. The interferometer has been fabricated experimentally by splicing a eccentric core single-mode fiber between two single-mode fibers. The interferometer has been applied as temperature, strain and refractive index sensor in the laboratory, respectively.