Design Of Multi - Service Optical Network Transmission System

With the rapid development of the optical fiber technology, optical fiber communication has become one of the most important modern means of communication owing to it’s advantages of bandwidth communications capacity, transmission distance, low loss, strong anti-interference ability and other characteristics. The technology is widely used in various kinds of occasions, especially the applications of fiber-optic communications in broadband local area network (LAN) has become a trend. However, with the improvement of people’s living standards and the rapid development of the network services, LAN needs to support multi-service types of signal and provide a proper real-time bandwidth aimed at multiservice signal, thus causing some prevalent problems such as more bandwidth distribution and shortage of fiber resource. In order to improve the efficiency of fiber utilization, share bandwidth resources, avoid duplication and low-level construction, building a high-bandwidth multi-service transport platform with the performance of wide adaptability, easy maintenance, low cost is a research hotspot appearing recently years.In the thesis, the multi-service optical network transmission system based on time-division multiplexing (TDM) and Coarse wavelength division multiplexing (CWDM) is studied. What’s more, a multi-service optical network transmission system is proposed, some associated hardware circuit design and software design are accomplished. The system consists of the multi-service data transceiver module, optical transmission module and monitoring module. The Multi-service data transceiver module collect multi-service data and transmit them based on TDM. Wherein the data acquisition circuit collect the video data, Ethernet data, audio data and control signal. The FPGA chip Spartan 3E (XC3S500E) is the core chip which is used to achieve multi-service data TDM transmission and 8B10B encoding on the basis of the Verilog language. The SN65LV1023A and SN65LV1224B chips are used to fulfil the multiservice data parallel-serial and serial-parallel conversion. The optical transmission module do the electro-optical conversion for multiservice data first, then transport the data with the help of CWDM. More detailed, the modules use SFP fiber optic transceivers to achieve the function of multi-service data electricity-light and light-electricity conversion. The wavelength division multiplexer and demultiplexer achieve the function of division multiplexing and demultiplexing for different wavelengths optical signal based on CWDM technology. The Monitoring module mainly achieves monitoring the states of SFP fiber optic transceiver and data acquisition circuit, and uploading the monitoring data to the PC processing system on time. The module uses STC12C5A60S2 microcontroller core chip to achieve the C language procedure compilation for monitoring process, and communicate with PC through the RS485 communication circuits.After the completion of the hardware and software design of the system, the emulation platform is built to debug for each module of the software and hardware, then the article presents a test prototype to verify the efficiency of the entire system. The test results show that the multi-service optical network transmission systems can achieve the multi-service data transmission through optical network and complete the real-time monitoring of the entire system. Besides, by using of TDM and CWDM dual multiplexing, the results certificates the superiority in improving the single optical fiber transmission capacity, saving the fiber resources and reducing the system cost. All in all, the multi-service optical network transmission system has wide application, moreover, the great economic and social benefit in broadband LAN construction will contribute to a bright future in its technology extension.