Cold start wavelength division multiplexing optical transmission system and its standard frequency generation method

摘要

end. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wavelength division multiplexing (WDM) optical transmission systems.;I. SUMMARY OF THE INVENTION It is an object of the present invention to provide a colt start type WDM optical transmission system and a method for generating the standard frequency, in which transmission lasers can automatically generate stable optical output at a standard frequency.;All. The present invention proposes a wavelength division multiplexing (WDM) optical transmission system using a distributed feedback (DFB) laser and a passive optical signal demultiplexer. The DFB lasers measure wavelengths under normal operating conditions and select lasers operating within half the channel spacing from the standard frequency for each channel. Although the WDM optical transmission system does not input the operating conditions required for operating the selected lasers at the standard frequency, the WDM optical transmission system automatically operates at the standard frequency when the switch of the system is turned on,;la. An important application of the invention is a wavelength division multiplexing optical transmission system.