| The way to deposit nonquarterwave multi-layer thin film filter by Leybold APS1104 DWDM coater is studied in detail in this thesis. First, basic principles and technology of thin film optics are studied, including thecalculation of the character of optical thin film, thin film design and coating. Then, working conditions of Leybold APS 1104 DWDM such as plasma source,evaporator, vacuum pump and film thickness monitoring, which are different fromgeneral coaters and are specifically designed for DWDM coating, are analyzed in detail.Working conditions that are for or not for coating multi-layer nonquarterwave stacks aresummarized and classified. A conclusion is drawn that it is the single wavelength directmonitoring method that leads to the difficulties in coating multi- layer nonquarterwavestack by Leybold APS 1104 DWDM. Nonquarterwave stack design requirements that are fit for single wavelength directmonitoring are put forward to cope with the problem. Nonquarterwave stack designstrategies are studied according to the requirements. The Ï constraint is created whichcan be used to quantitatively analyze film stack. The multi-layer nonquarterwave stacksdesigned in this way are experimented in the coating process, and the performance turnsout to be satisfactory. If a film stack consists of decades of layers, it's difficult to search for a stack thatmeets the requirements mentioned above manually, or even impossible. To meet therequirements automatically during thin film design, a brand new optimization methodwith constraints is investigated. Constraints are attached during thin film design to meetthe monitoring curve requirements. The method is realized by combining VBA(VisualBasic for Applications) and worksheet function in FilmStar software. The feasibility ofthe method is demonstrated by optimization design of edge filter and multi-layer filmstack with arbitrary trigger point.
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