Automatic spectral transmittance measurement system for DWDM filters

For many years, fiber-optics communication has become an essential part of the development of our modern society. For example, its significance comes from the increasing demands on real-time image transmission, multimedia communication, distance learning, video-conferencing, video telephone, and cable TV, etc. This paper is to develop an automatic transmittance measurement system for a DWDM (dense wavelength division multiplexing) filter. In this system, a grating-based monochromator is devised to generate a collection of monochromatic light with various wavelengths, instead of using an expensive tunable laser. From this approach, the cost of the proposed system will be much lower than that of those having the same functions, by one order. In addition, we simulate the spectral filtering to investigate the resolving power of the system. It appears that our simulations give quite satisfactory results.