Abstract: A method of adding a transceiver including a transmitter and a receiver to an optical network. The transceiver is controlled to enable the receiver while maintaining the transmitter in a disabled state. The receiver detects a presence of an optical signal at a first wavelength. If an optical signal at the first wavelength is not present, the transmitter is enabled. Responsive to detection that an optical signal at the first wavelength is present: a feature of the optical signal, and a match condition between the detected feature and a predetermined feature are detected. The transmitter is enabled responsive to detection of the match condition.

Abstract: A method of adding a transceiver including a transmitter and a receiver to an optical network. The transceiver is controlled to enable the receiver while maintaining the transmitter in a disabled state. The receiver detects a presence of an optical signal at a first wavelength. If an optical signal at the first wavelength is not present, the transmitter is enabled. Responsive to detection that an optical signal at the first wavelength is present: a feature of the optical signal, and a match condition between the detected feature and a predetermined feature are detected. The transmitter is enabled responsive to detection of the match condition.

Abstract: In an Optical Add-Drop Multiplexer, a drop section comprises a Wavelength Selective Switch (WSS) having at least one drop-port, the WSS being operative to couple a respective set of w (where w>1) wavelength channels from a received Wavelength Division Multiplexed (WDM) signal to each drop port. A respective 1:s power splitter is associated with each drop port. Each power splitter supplies the respective set of channels received from its drop port to each one of a corresponding set of coherent receivers. Each coherent receiver operates to receive a selected one of the respective set of channels.

Abstract: In an Optical Add-Drop Multiplexer, a drop section comprises a Wavelength Selective Switch (WSS) having at least one drop-port, the WSS being operative to couple a respective set of w (where w>1) wavelength channels from a received Wavelength Division Multiplexed (WDM) signal to each drop port. A respective 1:s power splitter is associated with each drop port. Each power splitter supplies the respective set of channels received from its drop port to each one of a corresponding set of coherent receivers. Each coherent receiver operates to receive a selected one of the respective set of channels.

Abstract: An add/drop multiplexer/demultiplexer (ADM) for switching, modulating and attenuating optical signals in a fiber optic network employing wavelength division multiplexing (WDM) is disclosed. The ADM is equipped an optical multiplexer for splitting an input WDM signal into individual optical signals, leading to respective 2.times.2 switches. Each switch has another input originating from a plurality of "add lines", and selects one of its inputs to be dropped and the other to continue along a main signal path. The retained signals may be modulated and attenuated prior to being tapped and finally multiplexed together by a WDM multiplexer. The tapped signals are optoelectronically converted and fed back to a controller, preferably a digital signal processor running a software algorithm, which controls the switching, modulation and attenuation.

Abstract: An add/drop multiplexer/demultiplexer (ADM) for switching, modulating and attenuating optical signals in a fiber optic network employing wavelength division multiplexing (WDM) is disclosed. The ADM is equipped an optical multiplexer for splitting an input WDM signal into individual optical signals, leading to respective 2.times.2 switches. Each switch has another input originating from a plurality of "add lines", and selects one of its inputs to be dropped and the other to continue along a main signal path. The retained signals may be modulated and attenuated prior to being tapped and finally multiplexed together by a WDM multiplexer. The tapped signals are optoelectronically converted and fed back to a controller, preferably a digital signal processor running a software algorithm, which controls the switching, modulation and attenuation.