Research On Signal Processing Of OSC In DWDM System

With rapid developments of computer and communication technologies, network capacity brings new challenge to the existed matured technologies and attracts more and more research. In this context, Dense Wavelength Division Multiplexing (DWDM) technique emerges as required. It can greatly increase the network capacity, make full use of the bandwidth of fiber and reduce the waste of network resources.In the DWDM system, Optical Supervisory Channel (OSC) is a relatively independent subsystem. It can monitor the network line in real-time, detect network breakdowns and solve them quickly, ensure the network operate normally and thus plays an important role in the DWDM system. In order to process the add/drop optical channel signal of OSC, it takes a significant role to carry out the optical-to-electric signal conversion and code conversion firstly.Based on the DWDM and OSC theories, this paper investigates the realization and performance testing of optical-to-electric signal conversion and code conversion, surrounding the developed DWDM terminal device and its key signal processing technique related to the OSC integrated circuit board. The main content includes:1. The development, structure, key techniques of DWDM system, as well as the concept and theory of OSC were analyzed. Based on them, the composition, structure of the developed DWDM terminal device and key techniques in the OSC module were introduced, including the optical-to-electric signal conversion and code conversion, data recording and intelligent analyzer.2. The function of the signal processing unit of the OSC integrated circuit board was designed, including optical-to-electric signal conversion and code conversion. The design proposal was planned integrally. Code conversion and line clock extraction were implemented by programing the complex programmable logic devices.3. A testing scheme to evaluate the performance of the signal processing in the OSC integrated circuit board was designed. The performance requirements were defined firstly and then a testing scheme was designed. Detailed procedures and the testing results were presented. Through the comparisons between the expected and practical testing results, the testing scheme was validated and furthermore the performance of the whole integrated circuit board was evaluated.