Study Of All-optical F-P Tunable Filter And Its Application In DWDM System

With the emergence and promotion of cloud computing, networking, high-definitiontelevision and other broadband integrated services, society put forward higher requirements tocommunication speed and stability. All-optical network based on the dense wavelengthdivision multiplexing (DWDM) is the best solution to the business development of high-speedtransmission, because it avoided the photoelectric conversion price, broke the limitations ofelectronic bottleneck. Realization of all-optical network in high-speed without bottleneckstransmission, which requires high-speed and integrated all-optical devices. Thus, the fibergrating with incomparable advantages is widespread concerned and studied in-depth.Fiber Bragg Grating is a new form of passive fiber structures in recent years. Owing tothe properties that the center wavelength of Fiber Bragg Grating can be tuned by strain ortemperature and that it is compatible with all-optical communication system, FBG has servedas a wavelength selecting and tuning component in tunable optical filter. Fabry-Perot filterbased on Fiber Bragg Grating showed its great superiority, and many investigations havereported that FBG-FP filter is used as a mode selector to achieve single-longitudinal-modefiber laser.In all-optical communication, absolutely managed ROADM (Reconfigurable OpticalAdd/Drop Multiplexers) is the key equipment for dynamic network control and managementflexibly. It not only can selectively add and drop any required wavelength, but also can adjustthe input optical power to balance the output signal gain. Therefore, the dense wavelengthdivision multiplexing channel achieved drop functionality.In this thesis, according to the specific technical request of fiber tunable filter on DWDM,Fiber Bragg Grating based tunable narrow-band filters for DWDM system applications weretheoretically and numerically studied in details. The main works are as follows:(1) An all fiber multi-cavity configuration based on Fiber Bragg Gratings is proposed andused as a filter, in order to improve the filtering performance of the single-cavity structuressuch as flatness of the top and steepness at the edge of transmission peak. The characteristicsof the transmission spectra for the configuration are analyzed and modeled in detail. Theresults show that the steepness of the peak slope can be improved by increase of fiber gratingreflectivity, and required band-width of the peak can be obtained by adjusting the cavitylengths in different applications. The comparison of the transmission peaks betweensingle-cavity and multi-cavity structures demonstrates the two cavity filter have betterfiltering performance.(2) The applications in tunable fiber lasers of tunable FP filter based on fiber Bragggratings were analyzed and simulated utilizing OptiSystem. The results showed that single longitudinal mode operation is confirmed by the fiber laser using FBG-FP.(3) A novel Reconfigurable Optical Add/Drop Multiplexer (ROADM) based on FBG-GPcavity tunable filter is designed. Input port and drop port are arranged on the one side ofROADM, and output and add port on another side. The simulation analysis shows that thedesigned device has power loss of1dB, and each channel can achieve dynamic gainequalization.(4) I test the ROADM, and simulate the DWDM system by using OptiSystem software,according to the characteristics of optical devices. Then, I also test optical performance andfeatures of the entire system, the results show that the designed ROADM, which would notimpact the DWDM system. So the system functions could meet the design requirements, andtotally meet the needs of all-optical network.