| The Reconfigurable Optical Add/Drop Multiplexer (ROADM), which can be configured dynamically, is an indispensable device for the evolution of Optical Networks from current dense wavelength division multiplexing system to all-optical network. What is the best way to improve the tuning speed of ROADM in order to adapt to the high speed transmission of data over optical network is a research hotspot. A new kind of electro-optical tunable ROADM was developed, it can upload and download specific carrier wave by regulating the voltages of its polarization conversion unit and wavelength tuning unit. Its tuning time is restricted in nanoseconds range.This thesis presents a voltage control module, which is based upon FPGA. It is designed for the new type ROADM specially. In this thesis, voltage control module design is subdivided into low-voltage multi-output part and high-voltage output part, both of two parts have been described in detail. And much work has been completed, such as designs of each part, selection and verification of each part, circuit design, program development, etc. Every part of the voltage control module have been tested and simulated to verify the validity and feasibility.In this module, FPGA chip is used as control processor, after receiving the control signal from PC through UART interface, it outputs data which is pre-stored in the customized RAM on the chip dynamically. The data is converted to 50 different voltages at the same time by 25 dual-channel ultra-high-speed Digital-to-Analog Converters. The voltages range from -5V to +5V, are in the accuracy of 0.04V. The tuning time is restricted in nanoseconds range. At the same time a flyback pulse step-up circuit with Feedback circuit has been used to output a high voltage. The voltage ranges from 0V to 300V continuously. The tuning time is restricted in millisecond range.Experiments show that, the requirements of high-speed tuning of the voltages can be satisfied by the voltage control module. |
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