Hardware Design and Implementation for Phase Shifting Control System of All-Optical OFDM Multiplexing Chips
|School||Huazhong University of Science and Technology|
|Keywords||Orthogonal Frequency Division Multiplexing (OFDM) Discrete Fourier Transform (DFT) Planar Lightwave Circuit(PLC) Temperature control Microcontroller|
All-optical Fourier Transform chip based on planar lightwave circuit (PLC) is regarded as the most potential experimental scheme because of compactness, easy to be implemented and suitable for integration. This chip could be introduced into all-optical Orthogonal frequency division multiplexing (OOFDM) optical communication, which could improve the performance of system and lower the costs, in addition could increase frequency effective and system capacity, and could reduce the dependence of system on high-speed electronic processing chips. The PLC-based chip utilizes thermo-optical effect to realize the phase-shift function. Then temperature control is indispensable to this chip. A thermal control circuit is designed in this thesis. Accuracy temperature control is essential because the phase-shift is very sensitive to temperature. The fluctuation of temperature will severely deteriorate the PLC-based chip’s performance. Therefore, this thesis bases on the theory of thermo-optical effect to PLC, according to function of temperature and phase, determines the accurate temperature to be stabilized, thereby designs an effective and efficient thermal control circuit .This thesis designs an effective and efficient phase control circuit accordingly using ADuC7024 arm microcontroller. Because of ADUC7024’s powerful ability, it could control four thermal control circuits simultaneously. Further more, its inner integrates several kinds of hardware interfaces which could reduce the costs and minimize the size.The phase control circuit comprises detective part, which utilizes the ADuC7024 microcontroller, thermal acquisition, DA, driving circuit of pulse width modulation which uses DRV591, Thermoelectric Cooler and hexamine. In depth, this thesis completes the four temperature control circuits Protel schematic design, and completes the PCB boards and production. Moreover, combines with software control to achieve the relevant interfaces, and debugs the circuit board, while completes the experimental test of the circuit boards.The testing results exhibit that the precision error of the control circuit is about±0.1oC. And the temperature control ranges -40oC to 100oC. Ultimately the thermal control circuit is accurately controlled, very low consume demanded as well as simple and elegant.