Ciena Corporation

Stephen R Harmon

Victor Mizrahi

Michael B Peters-Rodbell

Keith A Condict

Wesley R Jones

The present invention is directed toward a distributed intelligence fiber-optic communication network in which node control processors (NCPs) associated with each network element periodically transmit identification and status information to the other NCPs in the network. Various faults in the network can thus be readily identified, and appropriate tasks for modifying the network in response to the fault (such as rerouting around a defective network element) can be carried out. Further, information continues to be distributed among the NCPs even if a break occurs in a segment of fiber in the network.

Distributed intelligence wavelength division multiplexed network

The present invention provides a wavelength division multiplexed optical communication system with dynamically stabilized wavelength selectors. To accurately correlate the wavelength of a wavelength selector to the wavelength emitted by an optical transmission source, the present invention uses an optical detector and feedback loop to optimize the wavelength of an optical selection element in accordance with a wavelength of an incident optical channel. In one embodiment, the optical selection element is a Bragg grating associated with a grating wavelength controller, such as a temperature regulator or strain tuning system, to adjust the wavelength band of maximum reflectivity of the grating. The feedback loop communicates with the optical detector and the wavelength controller to modify the grating's reflection wavelength band in accordance with the wavelength of an incident optical channel.

WDM optical communication systems with wavelength-stabilized optical selectors

WDM optical communication systems with wavelength-stabilized optical

A network communication system comprising an optical communication path and a plurality of network elements disposed along the optical communication path. A first network element coupled to the optical communication path includes a first processor and a first optical component. The status of the first optical component being monitored by the first processor. The first processor generates a first electrical signal in accordance with the status of the first optical component. The first network element also includes a service channel transmitter coupled to the first processor and emits a second optical signal to the optical communication path at a second wavelength different than the first plurality of wavelengths in response to the first electrical signal. The second optical signal being modulated in accordance with the second electrical signal. A second network element is coupled to the optical communication path and includes a second processor, a second optical component coupled to the second processor and a service channel receiver coupled to the first processor and to the optical communication path. The receiver senses the second optical signal. The service channel receiver outputs a second electrical signal to the second processor in response to the second optical signal. The second processor controls the second optical component in response to the second electrical signal.

Span management system for wavelength division multiplexed network

A laser control system is disclosed including a microprocessor, which precisely adjusts the wavelength of light output from the laser by monitoring the transmissivity of an in-fiber Bragg grating coupled to the output of the laser. The Bragg grating is fabricated to have a minimum transmissivity at the desired output wavelength of the laser. The microprocessor continually adjusts the wavelength of the laser output to obtain substantially minimal transmissivity through the grating. At which point, the laser is locked to the desired wavelength. Alternatively, the microprocessor can monitor light reflected from the grating, and continually adjust the wavelength of the laser output to lock the laser at a wavelength providing substantially maximum reflectance by the grating.

Laser wavelength control device

In accordance with the present invention, an in-fiber Bragg grating is coupled to the output of a directly modulated DFB laser. The output of the DFB laser is spectrally broadened, but has peak optical power at the channel wavelength. Typically, the grating is designed to have a substantially vertical 'edge', i.e., segment of the transmissivity vs. wavelength characteristic, at a particular wavelength, between a transmission minimum and a transmission maximum. Amounts of light transmitted through and reflected by the grating are compared to adjust the channel wavelength to a desired wavelength at or near the edge of the grating.

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Severn, MD, United States of America

Stephen R Harmon