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Sycamore Networks, Inc. Patents
Sycamore Networks, Inc.
Chelmsford, MA
No. of patents:

Patent Number Title Of Patent Date Issued
8271610 Distributed content caching solution for a mobile wireless network September 18, 2012
A method in an electronic device provides local content to a user device in a communication network. The communication network includes an access network and a core network. In the access network, a content request is intercepted from the user device, which may be formatted according to
7826345 Network span protection using span identifiers November 2, 2010
Each span of a communication network, such as a BLSR ring, is assigned a unique span ID. When a node of the network detects a failure in a network span, the node exchanges commands, according to an automatic protection switching (APS) protocol, that request other nodes of the network to
7050561 Restoration scheme for mesh-based switching networks May 23, 2006
A method and apparatus are provided for the management of multiple-node networks to provide for efficient and rapid determination of an alternative connection path through the network to avoid a fault in the connection path. The present invention seeks to minimize the number of nodes
7012887 Method for restoring diversely routed circuits March 14, 2006
A method and apparatus for restoring a diversely routed circuit in a timely manner from an initial path failure includes the steps of receiving one or more triggers at one of a destination node and a source node of a first path. The trigger indicates a path failure. The method contin
6961525 Method for channel balance November 1, 2005
A method of channel balance for a channel balance section in an WDM optical network with a starting node, an ending node and a plurality of intermediate OADNs (Optical Add Drop Node) first determines express wavelengths and non-express wavelengths starting from the starting node, the
6952405 Coding scheme using a transition indicator for signal transmission in optical communications net October 4, 2005
A coding scheme is provided transporting encoded information over an optical communications link to a network. Multi-word information groups are analyzed to determine whether each of the information groups includes control characters. If the information group does not include any control
6912606 Generic serial bus architecture June 28, 2005
A serial bus is provided that supports multiple data transmission protocols. The serial bus allows a bus master to communicate with a variety of semiconductor devices that support a variety of serial interface standards. As a result, a single bus master may control and observe a JTAG
6862564 Network emulator March 1, 2005
A system and a method for providing an emulated network including a plurality of emulated networking devices, in which a number of network node executable images are employed. Each of the network node executable images corresponds to one of the emulated networking devices. The emulated
6859468 Method and system for mode stabilization of VCSELS using increased bias current February 22, 2005
The present invention discloses a vertical cavity surface emitting laser (VCSEL). The VCSEL comprises a first and second mirror stack. The VCSEL has an active region positioned between the first mirror stack and second mirror stack. Also, the VCSEL has a contact region in at least one of
6839871 Method for transparent multiplexing of SONET/ SDH streams January 4, 2005
Indicia are provided to a client of Out-of-Frame errors and message bit parity errors that occur during the transmission of a message through a network, wherein the message includes the client data multiplexed with other data and formatted into a message that includes a plurality of
6839866 System and method for the use of reset logic in high availability systems January 4, 2005
A method of providing reset logic in high availability computer systems is disclosed. The illustrative embodiment of the present invention uses probability theory in combination with redundant processors and components to ensure system availability. Detected errors are verified, and
6826372 Methods and apparatus for dynamic threshold setting for an optically amplified receiver November 30, 2004
An optical receiver circuit includes a differential limiter amplifier receiving a binary electrical waveform generated by an optical-to-electrical converter receiving an optical communications signal. Low-pass filter circuits are coupled to differential outputs of the limiter amplifi
6823470 Method and apparatus for correcting data November 23, 2004
A system and method is provided for using a first data channel to pass working data and a second data channel to pass error correction information. For example, this second data channel may be defined along a redundant data path. For example, this error correction information may be
6807001 Auto shutdown for distributed raman amplifiers on optical communication systems October 19, 2004
A method and apparatus for detecting if an optical module has been disconnected from a fiber span or if there has been a break in the span, and for automatically reducing the output signal level of the optical module such that the output signal level is within an acceptable safety li
6754208 Traffic spreading to reduce blocking in a groomed CLOS communication switch June 22, 2004
A method and apparatus are disclosed for spreading the component signals of a groomed input circuit through a three-stage CLOS switch network. The spreading algorithm includes sequentially evaluating each midstage switching module as to the availability of a connection between an ass
6741761 Method for achieving improved transmission performance over fiber using a Mach-Zehnder modulator May 25, 2004
A method for improving the bit error rate of a modulated optical signal transmitted over single mode fiber is provided. The modulating voltage supplied to a single arm or alternatively to both arms of a Mach-Zehnder modulator is increased to result in a reduced extinction ratio of the
6738262 Port filler baffle May 18, 2004
An apparatus for hindering the collection of dust and particulate matter within unutilized housings or ports of hardware component chassis is provided. A port filler baffle for occupying a port within a chassis includes a panel assembly sized and dimensioned to fit within the port of
6735357 Monitoring and control of all-optical cross connect fabrics using multiple laser sources May 11, 2004
An active control system and method for controlling the position and/or properties of optical components in an optical switch of an optical communications network is provided. The active control system utilizes a power-sharing scheme to provide an array of supervisory signals, which are
6681248 Method for port connectivity discovery in transparent high bandwidth networks January 20, 2004
In a network having a trace capability, a method to track the connectivity of the network uses the trace messages. A network manager creates a list of ports in the network and uses that list to track the connectivity. For each port, the manager first checks whether there is a current con
6661963 System and method for calibrating and operating a semiconductor variable optical attenuator December 9, 2003
A method and apparatus for controlling the attenuation level of a semiconductor VOA relative to an absolute temperature of the VOA without the use of a power monitor is provided. The method includes the step of providing a variable optical attenuator for attenuating the optical signa
6614569 System and method for narrow channel spaced dense wavelength division multiplexing/demultiplexin September 2, 2003
A method and apparatus for executing narrow channel spaced dense wavelength division multiplexing ("DWDM") includes an optical multiplexor/demultiplexor with channel add/drop having a first circulator and a second circulator. A first fiber Bragg grating couples with the first circula
6587630 Optical backplane cartridge July 1, 2003
An apparatus for supporting and protecting the optical backplane that permits adequate cooling of electronic components near the optical backplane and maintains optical connectors of the optical backplane in a predetermined and substantially static arrangement is provided. A cartridg
6580531 Method and apparatus for in circuit biasing and testing of a modulated laser and optical receive June 17, 2003
A method and apparatus for in-circuit biasing of a modulated laser and bit error rate testing of an optical transmitter and/or optical receiver under the control of a test controller. The test controller is communicably coupled to an interface of a module under test, as well as to extern
6557101 Methods and apparatus for upgrading programmable control logic without disturbing network traffi April 29, 2003
A network device includes latches disposed between control outputs of control logic such as a field-programmable gate array (FPGA) and control inputs of functional elements through which network traffic flows. The control logic generates a latch enable signal that controls the operation
6553175 Variable optical attenuator April 22, 2003
A method and apparatus for variable optical attenuation is disclosed. A variable optical attenuator is provided having a housing. Within the housing, a filter is mounted on a drive shaft of a motor such that the drive shaft passes through a substantially center point of the filter. The
6549312 Method for designing optical filter cards April 15, 2003
A method is provided for optical filter card design that facilitates a relatively efficient filter assignment algorithm solution resulting in a filter design that reduces a probability of unnecessary wavelength regenerations.
6529315 Optical amplifier providing dispersion compensation March 4, 2003
A dispersion-compensating fiber amplifier having a Raman pumped dispersion-compensating fiber and a distributed optical amplifier. The dispersion-compensating fiber is pumped such that the noise contribution of the dispersion-compensating fiber is reduced.
6504631 System and method providing control channel for wavelength-division multiplexed network January 7, 2003
A network including a control channel source node and a plurality of control channel destination nodes is interconnected by communications media in the form of a ring. The control and control channel destination nodes transfer information over a plurality of channels using wavelength
6496305 Two fiber support with single optical amplifier December 17, 2002
An optical amplifier for a 4-fiber system having two inputs and outputs is provided that makes use of a single amplifier rather than two separate amplifiers. The optical amplifier node makes use of an interleaver before and after the single amplifier to demultiplex and multiplex even and
6483637 System and method for per-band optical amplification November 19, 2002
A method and apparatus for amplifying an optical signal is provided. In accordance with one example embodiment of the invention, the optical amplification system includes an optical signal traveling through the system. At least one module of the optical amplification system is suitab
6456427 Systems and methods for reducing a signal spectrum tilt September 24, 2002
Methods and systems for reducing a first tilt of a spectrum of light transmitted via an optical fiber are provided. To reduce the first tilt, an amplifier, such as an erbium doped fiber amplifier, is configured to yield a gain spectrum with an opposite tilt to that of the first tilt.
6456409 Method and apparatus for extending fiber transmission distance with multiple pre-emphases in opt September 24, 2002
A Dense Wavelength Division Multiplexed (DWDM) optical transmission system that compensates for unequal channel performance over an extended fiber transmission distance. The DWDM optical transmission system includes optical transmitters at a transmitter end of a transmission path for
6445850 Method and apparatus for per-band compensation with gap-free band structure for high speed DWDM September 3, 2002
A high speed DWDM optical transmission system that reduces a fiber dispersion limit without reducing the total channel count of a multi-wavelength optical signal. The system achieves such reduction in the fiber dispersion limit by employing a multi-wavelength optical signal comprisin
6433904 Method and apparatus for improving transmission performance over wavelength division multiplexed August 13, 2002
Data transmission apparatus includes first and second optical transmitters coupled to an optical link. A forward error correction (FEC) coder is coupled to the input of the second optical transmitter. A first information signal having a first information rate is provided to the first
6433903 Optical management channel for wavelength division multiplexed systems August 13, 2002
A wavelength-division multiplexed (WDM) system includes an optical communications link with one or more optical amplifiers cascaded from an input end to an output end. Each amplifier has a predetermined optical gain throughout a pass band, and passes optical signals in the pass band
6430201 Method and apparatus for transporting gigabit ethernet and fiber channel signals in wavelength-d August 6, 2002
Multiple gigabit Ethernet (GbE) and Fiber Channel (FC) signals are multiplexed and transported on a wavelength-division multiplexed (WDM) communications link using synchronous optical network (SONET) signaling. A transmitter decodes the 8b/10b encoded GbE/FC signals to reduce their r
6400479 Optical power balancer for optical amplified WDM networks June 4, 2002
A wavelength division multiplexed (WDM) optical communications network is configured and operated to enable transmitter output power for a given wavelength channel to be adjusted to achieve a desired optical signal-to-noise ratio (OSNR) for the channel independently of the power leve
6396051 High resolution optical performance monitor for DWDM system May 28, 2002
An apparatus for measuring the optical-signal-to-noise ratio (OSNR) of an optical system is adapted to function in single channel or in multi-channel wavelength division multiplexed optical communication systems. An optical signal spectrum and a center frequency characterize the opti
6388805 Two fiber support with single optical amplifier May 14, 2002
An optical amplifier for a 4-fiber system having two inputs and outputs is provided that makes use of a single amplifier rather than two separate amplifiers. The optical amplifier node makes use of an interleaver before and after the single amplifier to demultiplex and multiplex even and

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