Abstract: An apparatus and method of monitoring multiple channel signals of a wavelength division multiplexing (WDM) signal in a WDM system. The optical signal monitoring apparatus includes: an optical demultiplexer having 2N+2 output ports, for receiving and demultiplexing by wavelength a wavelength division multiplexing (WDM) signal with N wavelengths, and outputting two output port signals for each channel via the 2N output ports and outputting two adjacent signals via the +2 output ports needed to measure the optical signal noise ratio outside the frequency range of the WDM signal; a signal conversion unit for receiving the output port signals from the optical demultiplexer and converting the received optical output port signals into digital signals; and a signal processing unit for receiving the digital signals and calculating the wavelength and optical power for each channel using the loss characteristics of the two output port signals of each channel.

Abstract: Disclosed is an opto-electrical cross connect device of high density including a shelf having a plurality of guide rails at its inner portions; a switch motherboard disposed on the rear surface of the shelf; an electric crosspoint switch positioned on the front surface of the switch motherboard; a plurality of switch connectors positioned on the front surface of the switch motherboard; an optical transceiver board mounted in the guide rail of the shelf; and, a transceiver connector disposed at the rear end of the optical transceiver board for connecting to the switch connector of the switch motherboard.

Abstract: A cross-connect device in an optical network which includes a demultiplexer for demultiplexing an input optical signal by channels; a plurality of arbitrary transmission optical receivers for converting the optical channel signals received from the demultiplexer to electrical signals and for recovering a clock signal and data according to a reference clock signal generated at the transmission rate of the electrical signals; a cross-connect switch for path-routing the electrical signals received from the arbitrary transmission optical receivers; a controller for controlling the path-routing of the cross-connect switch; a plurality of arbitrary transmission optical transmitters for converting the electrical signal received from each output port of the cross-connect switch to an optical signal; and, a multiplexer for multiplexing the optical signals received from the arbitrary transmission optical transmitters onto one stand of optical fiber.