Optical add/drop multiplexer/demultiplexer

An add/drop multiplexer/demultiplexer (ADM) for connection in a fiber optic network adapted to carry wavelength division multiplexed (WDM) optical signals, the ADM comprising:

• a wavelength demultiplexer having an input port for connection to the network and a plurality of output ports respectively connected to a plurality of optical input signal lines for carrying respective demultiplexed optical input signals;
• a wavelength multiplexer having an output port for connection to the network and a plurality of input ports respectively connected to a plurality of optical output signal lines for carrying respective demultiplexed optical output signals;
• a plurality of controllable optical switches, each having a first input connected to a respective one of the plurality of optical input signal lines, a first output connected to a respective one of the plurality of optical output signal lines, a second input connected to a respective one of a plurality of add signal lines and a second output connected to a respective one of a plurality of drop signal lines;
• a plurality of optoelectronic converters respectively intercepting the plurality of optical output signal lines;
• and
• a controller electronically connected to the optoelectronic converters and to the optical switches, for detecting dither signals contained in the demultiplexed optical output signals and controlling the optical switches according to instructions encoded in the detected dither signals.

An add/drop multiplexer/demultiplexer (ADM) for connection in a fiber optic network adapted to carry wavelength division multiplexed (WDM) optical signals, the ADM comprising:

• a first wavelength demultiplexer having an input port for connection to the network and a plurality of output ports respectively connected to a first plurality of optical input signal lines for carrying respective first demultiplexed optical input signals;
• a second wavelength demultiplexer having an input port for connection to the network and a plurality of output ports respectively connected to a second plurality of optical input signal lines for carrying respective second demultiplexed optical input signals;
• a first wavelength multiplexer having an output port for connection to the network and a plurality of input ports respectively connected to a first plurality of optical output signal lines for carrying respective first demultiplexed optical output signals;
• a second wavelength multiplexer having an output port for connection to the network and a plurality of input ports respectively connected to a second plurality of optical output signal lines for carrying respective second demultiplexed optical output signals;
• a first plurality of controllable optical switches, each having an input connected to a respective one of the first plurality of optical input signal lines;
• an output connected to a respective one of the first plurality of optical output signal lines;
• an input connected to a respective one of a first plurality of add signal lines;
• and an output connected to a respective one of a first plurality of drop signal lines;
• a second plurality of controllable optical switches, each having an input connected to a respective one of the second plurality of optical input signal lines;
• an output connected to a respective one of the second plurality of optical output signal lines;
• an input connected to a respective one of a second plurality of add signal lines;
• and an output connected to a respective one of a second plurality of drop signal lines;
• a first plurality of optoelectronic converters respectively intercepting the first plurality of optical output signal lines;
• a second plurality of optoelectronic converters respectively intercepting the second plurality of optical output signal lines;
• and
• a controller electronically connected to the optoelectronic converters and to the optical switches, for detecting dither signals contained in the demultiplexed optical output signals and controlling the optical switches according to instructions encoded in the detected dither signals.

An optical router for use in a fiber optic network adapted to carry wavelength division multiplexed (WDM) optical signals, the router comprising:

• a plurality of input ports for connection to the network and for carrying respective optical input signals;
• a plurality of output ports for connection to the network and for carrying respective optical output signals;
• demultiplexing means for separating the optical input signals into respective sets of demultiplexed optical input signals;
• multiplexing means for forming the output WDM optical signals from respective sets of demultiplexed optical output signals;
• switch means for selectively interconnecting the demultiplexed optical input signals to the demultiplexed optical output signals;
• and
• control means for controlling the switch according to instructions provided by dither signals embedded within the demultiplexed optical input or output signals.

An optical ADM (OADM) for a node of an optical WDM network, comprising:

• an optical switch operable in a straight-through mapping for connecting an input fiber with an output fiber, and in a cross-over mapping for connecting said input fiber with a drop fiber and an add fiber with said output fiber;
• first opto-electronic conversion means for converting a fraction of an incoming optical signal present on said input fiber into an input electrical signal;
• and
• a control unit connected to the first opto-electronic conversion means, for extracting an input control signal comprising at least routing instructions from said input electrical signal and for operating said optical switch according to said routing instructions.

An optical ADM (OADM) for a node of an optical WDM network, comprising:

• an optical switch operable in a straight-through mapping for connecting an input fiber with an output fiber, and in a cross-over mapping for connecting said input fiber with a drop fiber and an add fiber with said output fiber;
• first opto-electronic conversion means for converting a fraction of an incoming optical signal present on said input fiber into an input electrical signal;
• and
• a control unit connected to the first opto-electronic conversion means, for measuring the power of the input electrical signal and for operating said optical switch according to the measured power.

A node for an optical dense WDM network comprising:

• an optical demultiplexer for separating a multi-channel incoming signal into a plurality of incoming optical signals, each associated with an input fiber;
• an optical multiplexer for combining a like plurality of corresponding outgoing optical signals, each associated with an output fiber, into a multi-channel outgoing signal;
• for each respective pair of incoming-outgoing signals, an optical switch operable in a straight-through mapping for connecting said associated input fiber with said associated output fiber, and in a cross-over mapping for connecting said associated input fiber with a drop fiber and an add fiber with said associated output fiber;
• first opto-electronic conversion means for converting a fraction of an incoming optical signal present on said associated input fiber into an input electrical signal;
• and
• a control unit connected to the first opto-electronic conversion means, for extracting an input control signal comprising at least routing instructions from said input electrical signal and for operating said optical switch according to said routing instructions.