Abstract: Routing mechanisms for routing data via a plurality of optical switched (OS) networks, such as optical burst-switched (OBS) networks. A plurality of OBS networks are connected to form an enterprise network, which may further include non-OBS networks such as LANs and the like. Each of the OBS networks is modeled as an autonomous system (AS), and one or more edge nodes of each OBS network are designated as external gateway protocol (EGP) routers. Each EGP router maintains a routing table identifying routes that may be used to reach destination networks. The routing table is dynamically updated via update messages that comprise an extension to the Border Gateway Protocol (BGP) and account for optical routing considerations particular to OBS networks. In response to a routing request, data is sent from an internal node using an internal routing protocol to a BGP router edge node.

Abstract: A mechanism for recovering reserved resources in a wavelength-division-multiplexed based photonic burst switched (PBS) network in response to resource non-availability. The PBS network includes edge and switching nodes, which optically communicate information formatted into PBS control and data burst frames. Each PBS data burst frame is associated with a PBS control burst frame. A PBS control burst is sent to reserve resources along a lightpath comprising a concatenation of lightpath segments linked between in ingress edge nodes, switching nodes and egress edge nodes. During a subsequent data burst, an unavailable resource is detected at one of the switching nodes. In response, a resource cancellation message (RCM) comprising a control burst is sent to upstream and/or downstream nodes along the lightpath. Upon receiving the RCM, the corresponding resource reservation is cancelled, freeing the network resources for subsequent bandwidth reservations and access.

Abstract: An architecture and method for performing coarse-grain reservation of lightpaths within wavelength-division-multiplexed (WDM) based photonic burst-switched (PBS) networks with variable time slot provisioning. The method employs extensions to the RSVP-TE signaling protocol, which uses various messages to reserve resources. A resource reservation request is passed between nodes during a downstream traversal of the lightpath route connecting a source node to a destination node via one or more switching nodes, wherein each node is queried to determine whether it has transmission resources (i.e., a lightpath segment) available during a future scheduled time period. Soft reservations are made for each lightpath segment that is available using information contained in a corresponding label. If all lightpath segments for a selected route are available, a reservation response message is sent back upstream along the route from the destination node to the source node.

Abstract: An architecture and method for performing coarse-grain reservation of lightpaths within wavelength-division-multiplexed (WDM) based photonic burst switched (PBS) networks with variable time slot provisioning. The method employs a generalized multi-protocol label switched (GMPLS)-based PBS label that includes information identifying each lightpath segment in a selected lightpath route. A resource reservation request is passed between nodes during a forward traversal of the route, wherein each node is queried to determine whether it has transmission resources (i.e., a route lightpath segment) available during a future timeframe. Soft reservations are made for each lightpath segment that is available using information contained in a corresponding label. If all lightpath segments for a selected route are available, the soft reservations turn into hard reservations. The stored reservations enable quick routing of control burst that are employed for routing data during scheduled use of the lightpaths.

Abstract: An optical network, which includes edge and switching nodes, optically communicate information formatted into statistically multiplexed control and data bursts and/or metadata. Control bursts are transmitted prior to the data bursts to configure optical switches in selected switching nodes so that the data bursts do not require O-E-O conversion. Each edge node consists of an adaptive PBS medium-access layer (MAC) component in order to achieve the transmission throughput improvement. The adaptive PBS MAC component enables the PBS data burst size to adapt to the TCP flow, allowing the PBS data burst to be transmitted immediately for the TCP flow experiencing TCP slow start. It performs a “deep” packet inspection of control packets coming back to the data source from the destination PBS network edge node to detect packet losses.

Abstract: An optical network, which includes edge and switching nodes, optically communicate information formatted into statistically multiplexed control and data bursts and/or metadata that are framed within Wide Area Network Interface Sublayer (WIS) frames for 10 Gb/s Ethernet according to the IEEE 802.3ae Standard. Frames with control bursts are transmitted prior to frames with related data bursts to configure optical switches in selected switching nodes so that the frames with the data bursts do not require O-E-O conversion. Another optical network uses frames that are data-rate and format compatible with the OC-192 synchronous optical network (SONET) transmission format. The ingress node to the optical network inserts the MAC address of the egress node rather than the IP address of the data destination. For both networks, mapping table information is exchanged in the optical network in an out-of-band network.

Abstract: An optical network, which includes edge and switching nodes, optically communicate information formatted into bursts that are included in one or more optical channel transport unit (OTU) frames that are based on ITU-T recommendation G.709. The overhead portion of the OTU frame can include all of the fields defined in the G.709 standard, except that the two reserved bits are used to define an OTU frame type. When the FEC function is not used, the OTU frame can be arbitrarily partitioned to carry optical burst information. The information can be either control and/or data bursts or metadata related to the optical network and/or optical burst flow. When the FEC function is used, the OTU frame is used to include optical control or data bursts or optical metadata in the payload portion of the G.709 OTU frame.

Abstract: An intelligent photonic burst switching (PBS) module for use in a WDM optical switching network includes optical multiplexers and de-multiplexers, an optical receiver array, an optical transmitter array, a PBS fabric, and a control interface unit. The PBS module includes optical buffering in a form of tunable wavelength converters (TWCs) and variable time-delay optical circuits. The PBS module routes the received optical burst labels and network management control labels to the controller and optical burst data in a plurality of input lines, respectively. The optical output lines provide propagation paths for a plurality of TDM channels. More specifically, the controller processes the control signal and, responsive thereto, causes the PBS to route at least a portion of the data signal to one of the TDM channels. When the desired TDM channel is not available, the controller causes a TWC to effectively change the wavelength of at least a portion of the data signal.

Abstract: A modular reconfigurable multi-server system for use in a wavelength-division-multiplexed based photonic burst switched (PBS) network with variable time slot provisioning. An optical high-speed I/O module within the multi-server system enables it to serve as an edge node in the PBS network. The optical I/O module statistically multiplexes the incoming packets (e.g., IP packets or Ethernet frames) received from a legacy network, generates control and data bursts, which are then scheduled for transmission over the PBS network. The optical I/O module then optically transmits and receives the scheduled optical bursts according to traffic priority and available network resources.

Abstract: A modular reconfigurable multi-server system with hybrid optical and electrical switching fabrics for high-speed networking within a wavelength-division-multiplexed based photonic burst-switched (PBS) network with variable time slot provisioning. An optical high-speed I/O module within the multi-server system includes an optical switch with the control interface unit. A server module of the multi-server system statistically multiplexes IP packets and/or Ethernet frames to be transmitted over the PBS network, generate control and data bursts and schedule their transmission. Then, the server E-O converts the bursts, and then transmits the optical bursts to the optical I/O module. The optical I/O module then optically transmits the bursts to the next hop in the optical path after processing the optical control burst to configure the optical switch, which then optically switches the optical data burst without performing an O-E-O conversion.

Abstract: A waveguide Bragg grating (WBG) is apodized by varying the duty cycle of selected grating periods while fixing the pitch of the grating periods. In one embodiment, the WBG is implemented in a silicon substrate using polysilicon filled trenches of varying width while keeping the grating periods' pitch constant. The polysilicon trenches are formed so that if the width of one trench is increased compared to an adjacent grating period, the trench width in the other adjacent grating period (if present) is decreased.

Abstract: The architecture, system and operation of intelligent photonic burst switched (PBS) network consist of edge nodes and switching nodes. The PBS edge node includes a flow classifier, flow manager, and ingress/egress PBS MAC layer components. The flow classifier classifies information received from outside the PBS network into forward-equivalent classes. The flow manager determines whether the information is to be sent over the PBS network or some other destination supported by the PBS edge node. Information to be sent over the PBS network is processed by the ingress PBS MAC layer component, which assembles the information into data bursts, schedules the transmission of the data burst, builds a control burst, and frames the data and control bursts, which are to be optically transmitted over the PBS network. The egress PBS MAC layer component receives control bursts and the corresponding data bursts, de-frames the data bursts, and appropriately assembles the data.

Abstract: A wavelength-division-multiplexed based photonic burst switched (PBS) network, which includes edge and switching nodes, optically communicate information formatted into PBS control and data burst frames. Each PBS data burst frame is associated with a PBS control burst frame. A PBS burst frame includes a PBS burst header and burst payload having fields to indicate whether: (a) the PBS burst frame is a PBS control burst; (b) the control burst is transmitted on a wavelength different from that of the associated PBS data burst; and (c) the PBS burst frame has a label for use in a generalized multi-protocol label swapping (GMPLS)-based control system. The PBS burst payload frame includes fields to indicate (a) specific PBS payload information; (b) PBS data payload; and (c) an optional PBS payload frame check sequence (FCS) for error detection.

Abstract: A method and apparatus for scheduling data burst transmission in a wavelength-division-multiplexing photonic burst-switched network is disclosed. In one embodiment, a scheduler determines a set of weighting factors at each wavelength for each of the lightpath segments among all the network nodes. These weighting factors may be used to calculate a set of coarse-grained bandwidth allocation factors, one for each potential lightpath formed from the available lightpath segments between an ingress node and an egress node. The scheduler may schedule the transmission of the data burst on one of the lightpaths that has a coarse-grained bandwidth allocation factor which indicates that it can support the requested bandwidth. The scheduler may periodically update the set of weighting factors at each wavelength for each of the lightpath segments.

Abstract: An optical polarization modulator (OPM) for use in an optical communication system includes two polarizing beam splitters (PBSs) and an adjusting stage coupled between the PBSs. One PBS receives an input optical signal with an arbitrary state of polarization (SOP) and splits it into its TE and TM components. The adjusting stage can change the amplitude and/or relative phase between the TE and TM components to help achieve a desired state of polarization (SOP). The ACS and PCS may include MZIs to both adjust the amplitude and the relative phase difference between the TE and TM components. Alternatively, the OPM may include an amplifier and a phase shifter for each component. The second PBS combines the adjusted components to form the output signal with a desired SOP. Another embodiment of the OPM includes an Y-junction coupler, two plasma optical-effect silicon phase shifter stages, a 2×2 3-dB coupler and a PBS.

Abstract: A method and apparatus for control and data burst routing in WDM photonic burst-switched network is disclosed. In one embodiment, only the control bursts and network management labels are going through optical-electrical-optical conversion inside the photonic burst switching (PBS) module. The building blocks of the control processing unit inside the PBS module may include input and output buffers, control burst parser, burst scheduler, PBS configuration and control, contention resolution, forwarding engine, network management controller, control burst generator, and queue manager. The contention resolution block may be used to resolve resource contention between multiple data bursts. Such contention resolution may take the form of adding additional delays to one of the data bursts, changing one of the data bursts to an alternate wavelength, or dropping some of the data bursts based on various criteria such as relative priority and wavelength.

Abstract: A waveguide Bragg grating (WBG) is apodized by varying the duty cycle of selected grating periods while fixing the pitch of the grating periods. In one embodiment, the WBG is implemented in a silicon substrate using polysilicon filled trenches of varying width while keeping the grating periods' pitch constant. The polysilicon trenches are formed so that if the width of one trench is increased compared to an adjacent grating period, the trench width in the other adjacent grating period (if present) is decreased.

Abstract: A semiconductor-based gain equalization device, method and apparatus. In one aspect of the present invention, an apparatus according to an embodiment of the present invention includes a semiconductor material. An optical path is included through the semiconductor material and is optically coupled to receive and transmit an optical beam. The gain equalization device is disposed in the semiconductor material. The optical gain equalization device includes a plurality of Bragg gratings disposed in the semiconductor material optically coupled to receive and transmit the optical beam. Each of the plurality of Bragg gratings have a different Bragg wavelength. The optical beam is to be directed from plurality of Bragg gratings with a non-uniform spectral response to compensate for the spectral non-uniformity of optical amplifiers.

Abstract: An optical polarization modulator (OPM) for use in an optical communication system includes two polarizing beam splitters (PBSs) and an adjusting stage coupled between the PBSs. One PBS receives an input optical signal with an arbitrary state of polarization (SOP) and splits it into its TE and TM components. The adjusting stage can change the amplitude and/or relative phase between the TE and TM components to help achieve a desired state of polarization (SOP). The ACS and PCS may include MZIs to both adjust the amplitude and the relative phase difference between the TE and TM components. Alternatively, the OPM may include an amplifier and a phase shifter for each component. The second PBS combines the adjusted components to form the output signal with a desired SOP. Another embodiment of the OPM includes an Y-junction coupler, two plasma optical-effect silicon phase shifter stages, a 2×2 3-dB coupler and a PBS.

Abstract: An intelligent optical burst switching module for use in an optical switching network includes an optical receiver array, optical transmitter array, a core switch unit and a control unit. The core switch unit routes optical control and data signals received via a plurality of optical input lines to the optical receiver array and a plurality of output lines, respectively. The optical output lines provide propagation paths for a plurality of TDM channels. The optical receiver array converts the optical control signal to an electrical signal. The control unit processes the converted control signal and, responsive thereto, causes the core switch unit to route at least a portion of the data signal to one of the TDM channels. The control unit also causes the optical transmitter to generate a new optical control signal and cause the switch unit to route the new control signal to another of the TDM channels.