Design And Implement Of The Optical Filters Control System Based On VCF

Since Optical Fiber Communication based on WDM is used more and more widely, the crucial devices are also updated again and again, especially the optical filter, which plays an important role in WDM and needs improving continually. In most cases, optical filters are designed as passive components and run without any control.In this paper, a novel controlling system using active components is presented and implemented. This system is on the basis of the VCF optical filter module and involves both hardware and software control.Started from introduction of Optical Fiber Communication based on WDM, some familiar structures of optical filters were introduced and their advantages as well as their disadvantages were analyzed in this paper. The characters of the liner variable filter module used in this system were illuminated in detail. The related parameters of the stepping motor we needed were calculated according to the formulas provided by the producer. Then we chose the right one for the VCF module.Hardware control and software control were involved in this controlling system. The hardware design was subject to the design standards for hardware. And Electrical Specofication, Electrical Interface Assignment, Electical Inerface Definitions were introduced. Then, the whole hardware circuit was divided into functional blocks. The detailed schematic diagrams were shown in the paper. At last of the part, something about the testing board, which was designed for testing and acted as a host, was also given. The software design included firmware architecture, boot loader and operational firmware. The operation methods when the boot loader begins to run was presented , as well as some flow charts and some programs.Operation firmware, which is the emphasis in this paper, was divided into functional blocks and was described in detail. The content included command handle of host, UART driver and so on. After several familiar curve algorithms were compared with each other and the stepping motor dynamic models was analysed, a new kind of curve algorithm was brought forward. The paper also described how to calculate the function, how to get the data table, and how to realize it.The chapter about testing consisted of hardware test and software test. In the hardware test, ESD and EFT test were done and their test environment, test standards and the results were listed. According to the requirements of the design, software test was done and the result was given. A simple WDM testing environment was built with some instruments. After a great deal of test, their results demonstrated that the control system designed in this paper was full and creditable.This control system has been applied into practical uses in WDM system.