Wavelength Division Multiplexing Thin-film Filter Tolerance And Temperature Stability

Along with the fast development and broad application of optical communication, thin film DWDM devices are used widely for the excellent temperature stability and high channel insulation in the DWDM system. Therefore, to understand and analyze their working performances is very important for us.In the thesis, the development of optical thin film and optical communication system is summarized firstly. Then thin film design , deposition and monitor systems and technologies are introduced. Based on these introductions, the computing models and formulas of thin film characteristics, error sensitivity, monitor simulation and influence of monitor light' s bandwidth are deduced. With these models and formulas, the software of monitor simulation and error tolerance analysis for DWDM thin film filters is built.For the high precision of thin film multi F-P cavity DWDM filter, thesis analyzes the tolerance of thickness and refractivity index error, sensitivity of each thin film layer and influence level to the whole performance of filter. The thesis also simulates the practical capability of SOGHz narrow band-pass filter on Pass Band Width and Ripple. Meanwhile, the requirement of monitor light' s width is advanced after simulation. In the thesis, some filters that have closing performance are compared in the error tolerance characteristic and the best one for production is selected. At the last of this section, the error tolerances of multi-peaks filter and EDFA gain flatting filter are also analyzed.Thesis also discusses the temperature stability of DWDM thin film narrow band-pass filter. The calculating formulas of central wavelength drift based on thin film microstructure and thermal-stress deformation are deduced, the drift of DWDM filter is calculated with these formulas. It is also found that replacement of substrate and adjustment of film stack structure would lead to the change of drift, this will enhance the temperature stability of filter.Finally, summarization of all these works and advice for the future work are made in the thesis.