Designing And Fabrication Of EDFA Splice Closure Used In Ultra-long Distance Optical Fiber Communication System Without Repeaters

The establishment and stable operation of ultra-long distance optical fibertransmission system is meaningful for the development of national high voltagetransmission network. This thesis focuses on the key part the remote pumping amplifiertechnology. Researching in theory and doing numerical simulation using MATLAB to getthe temperature dependence of the erbium-doped fiber amplifier. As the temperature rises,the signal gain decrease, but the noise figure increases. The main reason is thattemperature change affects the electrons distribution of the erbium ion on sublevel. Wehave designed experiments to demonstrate this result.Based on the temperature dependence of EDFA, the connect box was designed andproduced, and experiments were carried out on the engineering project. The mechanicalstructure was well designed for the connect box with innovative cooling solution to solvethe cooling problem without air convection in confined space, the thermodynamiccalculation was done for the structure, then refrigerating output was maintained as keepingthe best working temperature for the erbium fiber. This provides a theoretical foundationfor solar panels selection. Thesis described the position of varies of devices and made areasonable layout for lines so that it is easy to work with on the actual installation, alsoproposed in the actual construction of the tower on the installation. Photovoltaic powersystem was selected as the power source for the temperature control circuit. Analysis andcalculation was carried out for the required power of the EDFA connecting box to keep theoperating temperature. Model is established to decide the battery capacity and solar panelcapacity. Suitable battery and solar panel were chose during variety of products on themarket. The author studies the working principle of the TEC and selects the appropriateproduct as TEC cooling system thermostat heating unit. Using ADN8831as the maincircuit chip, building several functional modules such as temperature sensing, differential amplifier, power amplifier and low pass filtering. Complete the TEC drive circuit. In orderto work stably in the field, this thesis also designed a lightning protection filter circuit.