Research Of The Optical Add/Drop Multiplexer Based On Thin Film Filter

With the development of communication technology, the information service requirements are increasing steadily, requirement a large-capacity and high-speed transmission network. Therefore, next generation network-all-optical communication network (AON)-has been produced. The Wavelength Division Multiplexing (WDM) AON has become the first choice to develop the transmission network, and Optical Add/Drop Multiplexer (OADM) is one of the key techniques to construct it. OADM which overcomes the electronic bottleneck of traditional technology achieves to add/drop directly signals from core network to local network in the optical formation. OADM reduces the complexity of network nodes devices and accelerates speed of business assignment. In the optical domain, OADM can make transmission of signals transparently.This paper summarized existing basic of OADMs, including domestic and foreign. Structures, working theories and pros and cons of kinds of the OADM are analyzed. On the basis, writer puts forward an OADM based on thin film filter, introducing its structure and working theory.The capability of thin film filter, which is a key component of a new OADM, affects the performance of OADM. First of all, this paper introduced Maxwell equitation of electrical magnet promulgation, then, comprehensively analyzed optical characters of thin film. Used TFCalc software to design and simulate a thin film filter which meets design requirements of DWDM system narrowband filter. Analysis of the factors affecting transmission spectrum, it includes ratio of high and low thin films, the number of cycles of high and low thin films, interference grade of spacer layer and the number of filter cavities. Studied how to restrain multi-cavity filter passband ripples. Used Optisystem software to simulate the OADM based on thin film filter. The simulation results meet OADM design standards.