Abstract
A dense wavelength division multiplexing (DWDM) transmission scheme with two thin-film filters (FWHM bandwidth 100 GHz and 200 GHz) has been realized to evaluate the minimum channel interval needed for a satisfactory bit error ratio. For this purpose, detailed research was conducted into the impact of the filters on the optical signal's de-multiplexing in a DWDM system, in which the measurements of eye diagrams and the optical power spectral densities of a received signal were made. From the results of measurements the minimum channel interval has been found for the optical filters that ensures reliable data transmission and higher spectral efficiency of the whole system. It was found that for a DWDM system with a 100 GHz filter a sufficient channel interval is 75 GHz at 10 Gbit/s data transmission speed, which means that its spectral efficiency is increased from 0.1 bit/s/Hz to 0.1333 bit/s/Hz.