Optical transmission equipment and supervisory system thereof

摘要

The dependency on a wavelength makes it difficult to lengthen the distance as trying to make the density of the wavelength division multiplexing higher but to enhance the density of the wavelength as trying to make the distance longer. In order to overcome such difficulty, the present invention is arranged to provide an optical signal expander module having a group of wavelength bands in a transmission system. This expander is served to solve the problem of the dispersion and realize both the long distance and the high density of the wavelength division multiplexing that can be traded off.