Mechanism for tracking wavelengths in a DWDM network without specialized hardware

A node configured for operation in a wavelength division multiplexed (WDM) network, the node comprising:

• a network interface device configured to interface optical signals to and from the WDM network;
• and
• a processor configured to:
• receive a trigger configured to initiate tracking of a wavelength through the WDM network along a path associated with an optical connection;
• generate a digital channel key, wherein the digital channel key comprises a stream of bits that serves as a unique channel identifier for the optical connection;
• control the network interface device to generate a slow tone on a carrier optical signal, the slow tone indicating routing information for a wavelength, combine the carrier signal with at least one of a plurality of optical signals transmitted to the WDM network, and include the digital channel key in the slow tone;
• and
• send a request to nodes along the path to freeze their respective automatic power control mechanism for a duration of wavelength tracking or until a failure is identified at which time automatic power control is resumed for all nodes along the path.

In a wavelength division multiplexed (WDM) network having a plurality of interconnected nodes sending data to each other along wavelength paths, at least one intermediate node having one or more optical amplifiers operating under automatic power and gain control in normal operation, a method comprising:

• suspending automatic power control at the at least one intermediate node in a path of the WDM network to allow a slow tone on a carrier optical signal sent by a sending node to pass along the path, the slow tone indicating routing information for a selected wavelength;
• and
• at the at least one intermediate node, detecting the slow tone on the carrier optical signal;
• querying the at least one intermediate node to obtain connection information for the selected wavelength from the at least on intermediate node;
• and
• analyzing the connection information to determine if the selected wavelength is traveling correctly along the path.

In a wavelength division multiplexed (WDM) network having a plurality of interconnected nodes sending data to each other along wavelength paths, at least one intermediate node having one or more optical amplifiers operating under automatic power and gain control in normal operation, a method comprising:

• requesting suspension of automatic power control at the at least one intermediate node in order to allow a slow tone on a carrier signal in the path of the WDM network to pass through the at least one intermediate node;
• generating a slow tone to include routing information for a selected wavelength without using dedicated pilot tone hardware;
• and
• modulating the slow tone on an optical carrier signal to enable tracking of a selected wavelength between a sending node and a receiving node.

A non-transitory computer-readable storage medium storing instructions, that when executed by a processor, cause the processor to:

• control an optical amplifier in a node along a wavelength path in a Wavelength Division Multiplexed (WDM) network from a first node to a second node to disengage an automatic power control mechanism in order to allow a modulated optical signal for said wavelength path to go through and be detected;
• control a network interface device in order to detect said modulated optical signal for said wavelength path, said modulated optical signal having been modulated onto a carrier tone and including routing information for said wavelength path;
• and
• control said optical amplifier in said node to resume normal operations for amplifying user data under automatic power control after said wavelength path is tracked through said WDM network to a destination node or until a failure is identified.