At+t Corp.

At&t Intellectual Property I, L.p.

Jeevan Prakash Dodley

David Michael Britz

Robert Raymond Miller, Ii

Lih-Yuan Lin

Matthew J Sherman

Christopher Lee Rutledge

A system that incorporates teachings of the subject disclosure may include, for example, a central controller that performs operations including monitoring multiple network nodes, at least some of the network nodes being in communication with others through respective point-to-point links. Each point-to-point link includes a respective free space optical channel. The central controller detects optical received signal strength of a free space optical channel falling below a certain level and provides control signals to reconfigure the multiple network nodes. Signals are re-routed along one of the respective point-to-point links through other network nodes responsive to detecting the optical received signal strength falling below the certain level Other embodiments are disclosed.

Optical/radio local access network

A system that incorporates teachings of the subject disclosure may include, for example, a central controller that executes instructions facilitating performance of operations including monitoring multiple network nodes, at least some of the network nodes being in communication with others through respective point-to-point links. Each point-to-point link includes a respective free space optical channel. The central controller detects optical received signal strength of a free space optical channel falling below a certain level and provides control signals to reconfigure the multiple network nodes. Signals are re-routed along one of the respective point-to-point links through other network nodes responsive to detecting the optical received signal strength falling below the certain level Other embodiments are disclosed.

A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path coupled to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network. A method of communicating in a network having plural links includes sensing the presence of a received signal failure resulting from at least one of rain and fog. The method further includes sending data in a free space optical channel of the first link when the received signal failure sensed is due to rain and sending the data in an RF channel of the first link when the received signal failure is due to fog.

A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path couples to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links to corresponding users, an optical switch coupled to the plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network. A method of communicating in a network having plural links includes sensing the presence of a received signal failure by monitoring channel losses in a first link, the received signal failure resulting from at least one of rain and fog. The method further includes sending data in a free space optical channel of the first link when the received signal failure sensed is due to rain and sending the data in an RF channel of the first link when the received signal failure sensed is due to fog.

An architecture for facilitating wavelength-specific and packet-switched routing comprises a primary metropolitan fiber ring, a primary distribution/aggregation node in the primary metropolitan fiber ring and a local service domain further comprising a secondary aggregation node in communication with the primary distribution/aggregation node. A network to provide local metropolitan switching and routing and broadband local access distribution described in terms of its component layers comprises a distribution/aggregation routing layer that interfaces with a primary fiber metropolitan ring and a local customer primary distribution/aggregation node via transport branches of a mesh architecture, a local distribution and routing layer that routes specific wavelengths and newly assigned wavelengths to and from a customer's premises and a cross-connect layer that handles customer specific wavelength and packet routing via one of fiber, millimeter wave radio and free space optical communications.

Metropolitan networks based on fiber and free space access distribution system

A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path couples to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links to corresponding users, an optical switch coupled to the plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network. A method of communicating in a network having plural links includes sensing the presence of a received signal failure by monitoring channel losses in a first link the received signal failure resulting from at least one of rain and fog. The method further includes sending data in a free space optical channel of the first link when the received signal failure sensed is due to rain and sending the data in an RF channel of the first link when the received signal failure sensed is due to fog.

A method for facilitating wavelength-specific and packet-switched routing comprises the steps of demultiplexing wavelengths propagating on a primary metropolitan fiber ring, determining a destination address for the wavelength, accessing a look-up table, determining if the destination address matches a local address contained in the look-up table and switching the wavelength based on a result of the determining step. A method for providing local metropolitan switching and routing and broadband local access distribution described in terms of the functions of the layers comprises the steps of interfacing with a primary fiber metropolitan ring and a local customer primary distribution/aggregation node via transport bran ches of a mesh architecture, routing specific wavelengths and newly assigned wavelengths to and from a customer's premises and handling customer specific wavelength and packet routing via one of fiber, millimeter wave radio and free space optical communications.

Metropolitan networks based on fiber and free space access distribution method

A free space wavelength duplexed system includes a first and second terminals where each terminal includes a receiver part and a transmitter part, and the receiver includes a telescope, and optical-to-electrical converter, and an optical amplifier coupled between the telescope and the optical-to-electrical converter.

Free space duplexed optical communication with transmitter end multiplexing and receiver and amplification

A free space communication system includes first and second terminals, and the first terminal includes a transmitter to transmit an input signal. The transmitter has plural laser sources, at least one optical delay line and a telescope. Each laser source modulates the input signal onto a wavelength that is distinct from a wavelength of each other laser source. The plural laser sources include a first laser source and at least one other laser source, and the at least one optical delay line is coupled to a respective output of the at least one other laser source. The telescope projects an output of the first laser source and an output of each of the at least one optical delay line toward the second terminal. Alternatively, a free space communication system includes first and second terminals, and the first terminal includes a transmitter to transmit an input signal. The transmitter has at least one electrical delay line, plural laser sources and a telescope. The at least one electrical delay line delays the input signal. The plural laser sources include a first laser source and at least one other laser source, the first laser source modulates the input signal onto a first wavelength, and each of the at least one other laser source modulates an output of a corresponding electrical delay line onto a wavelength that is distinct from the first wavelength. The telescope projects an output of each of the plural laser sources toward the second terminal.

Free space optical communication link with diversity

An optical switch includes an input optical fiber, an output optical fiber and a mirror that is either inclinable or rotatable or both and reflects a lightwave signal from the input optical fiber into the output optical fiber. The switch further includes a control circuit to sense a misalignment error and to adjust the mirror to correct the misalignment error. The misalignment error may be either an inclination misalignment error, a rotation misalignment error or both. In an alternative embodiment, an optical switch includes an input optical fiber that includes an input core and an input cladding, an output optical fiber that includes an output core and an output cladding, an input GRISM to insert a calibration signal into the input cladding and a mirror that is adjustable. The mirror reflects a lightwave signal from the input core into the output core and reflects the calibration signal from the input cladding into the output cladding. The optical switch further includes an output GRISM to extract the calibration signal from the output cladding and a control circuit to sense a misalignment error based on the extracted calibration signal. The misalignment error includes an inclination misalignment error or a rotation misalignment error or both. The control circuit includes circuitry to adjust the mirror to correct the misalignment error. In an alternative embodiment, an optical switch includes an input optical fiber, an output optical fiber and a rotatable mirror that has diffraction gratings etched thereon. The mirror reflects a lightwave signal from the input optical fiber into the output optical fiber. The optical switch further includes a control circuit to adjust a rotation angle of the mirror to select a wavelength that can be diffracted into the output optical fiber according to a spacing of the diffraction gratings.

Growing community of inventors

Parsippany, NJ, United States of America

Jeevan Prakash Dodley