Patents by Inventor Rajiv Ramaswami

Rajiv Ramaswami has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20040258408
    Abstract: Methods, apparatus and systems for regenerating, monitoring and bridging optical signals through an optical cross-connect switch to provide increased reliability. A self testing method, apparatus and system for an optical cross-connect switch. An optical-to-electrical-to-optical converter (O/E/O) is provided in an optical cross-connect switch to provide optical-electrical-optical conversion. I/O port cards having an optical-to-electrical-to-optical converter are referred to as smart port cards while I/O port cards without an optical-to-electrical-to-optical converter are referred to as passive port cards. Test port/monitor cards are also provided for testing optical cross-connect switches. Methods, apparatus and systems for performing bridging, test access, and supporting redundant optical switch fabrics are also disclosed.
    Type: Application
    Filed: August 27, 2003
    Publication date: December 23, 2004
    Inventors: Rajiv Ramaswami, Robert R. Ward
  • Patent number: 6813407
    Abstract: Methods, apparatus and systems for regenerating, monitoring and bridging optical signals through an optical cross-connect switch to provide increased reliability. A self testing method, apparatus and system for an optical cross-connect switch. An optical-to-electrical-to-optical converter (O/E/O) is provided in an optical cross-connect switch to provide optical-electrical-optical conversion. I/O port cards having an optical-to-electrical-to-optical converter are referred to as smart port cards while I/O port cards without an optical-to-electrical-to-optical converter are referred to as passive port cards. Test port/monitor cards are also provided for testing optical cross-connect switches. Methods, apparatus and systems for performing bridging, test access, and supporting redundant optical switch fabrics are also disclosed.
    Type: Grant
    Filed: August 26, 2003
    Date of Patent: November 2, 2004
    Assignee: Nortel Networks Limited
    Inventors: Rajiv Ramaswami, Robert R. Ward
  • Publication number: 20040208509
    Abstract: An upgradeable photonic networking apparatus and method uses components in the upgradeable photonic networking apparatus to establish a number of alternate optical paths around an upgradeable element. The upgradeable element can be replaced with a new element introduced into the number of alternate optical paths, or else the upgradeable element can be upgraded after which optical paths are restored through the upgradeable element.
    Type: Application
    Filed: September 27, 2002
    Publication date: October 21, 2004
    Inventors: Ornan A. Gerstel, Rajiv Ramaswami
  • Patent number: 6795602
    Abstract: A fiber optic switch (400) includes a fiber optic switching module (100) that receives and fixes ends (104) of optical fibers (106). The module (100) includes numerous reflective light beam deflectors (172) which may be selected as pairs for coupling a beam of light (108) between a pair of optical fibers (106). The module (100) also produces orientation signals from each deflector (172) which indicate its orientation. A portcard (406) included in the switch (400) supplies drive signals to the module (100) for orienting at least one deflector (172). The portcard (406) also receives the orientation signals produced by that deflector (172) together with coordinates that specify an orientation for the deflector (172). The portcard (406) compares the received coordinates with the orientation signals received from the deflector (172) and adjusts the drive signals supplied to the module (100) to reduce any difference between the received coordinates and the orientation signals.
    Type: Grant
    Filed: December 1, 2000
    Date of Patent: September 21, 2004
    Inventors: Armand P. Neukermans, Timothy G. Slater, Tyler L. Baughman, James P. Downing, John S. Forker, Gregory A. Reznick, Sam Calmes, Steven M. Clark, Jack D. Foster, Marc R. Schuman, Rajiv Ramaswami
  • Patent number: 6792174
    Abstract: Methods, apparatus and systems for signaling information between an optical cross-connect switch and attached network equipment such as Internet Protocol (IP) routers, WDM terminals, SONET add/drop multiplexers and ATM switches. In one embodiment, an out-of-band signaling interface between an optical cross-connect switch and attached network equipment is realized by using an out-of-band communication channel over a network. In another embodiment, a decentralized signaling interface is provided by one or more dedicated signal lines between an optical cross-connect switch and attached network equipment.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: September 14, 2004
    Assignee: Nortel Networks Limited
    Inventor: Rajiv Ramaswami
  • Publication number: 20040131356
    Abstract: A wavelength division multiplexed optical communication system includes a plurality of optical line terminals which may be part of separate in service networks, each having a line interface and an all-optical pass-through interface including a plurality of pass-through optical ports, and each also including a plurality of local optical ports which are connectable to client equipment and an optical multiplexer/demultiplexer for multiplexing/demultiplexing optical wavelengths. The optical multiplexer/demultiplexer may include one or more stages for inputting/outputting individual wavelengths or bands of a predetermined number of wavelengths, or a combination of bands and individual wavelengths.
    Type: Application
    Filed: December 18, 2003
    Publication date: July 8, 2004
    Applicant: TELLABS OPERATIONS, INC.
    Inventors: Ornan A. Gerstel, Rajiv Ramaswami
  • Publication number: 20040076365
    Abstract: Methods, apparatus and systems for regenerating, monitoring and bridging optical signals through an optical cross-connect switch to provide increased reliability. A self testing method, apparatus and system for an optical cross-connect switch. An optical-to-electrical-to-optical converter (O/E/O) is provided in an optical cross-connect switch to provide optical-electrical-optical conversion. I/O port cards having an optical-to-electrical-to-optical converter are referred to as smart port cards while I/O port cards without an optical-to-electrical-to-optical converter are referred to as passive port cards. Test port/monitor cards are also provided for testing optical cross-connect switches. Methods, apparatus and systems for performing bridging, test access, and supporting redundant optical switch fabrics are also disclosed.
    Type: Application
    Filed: August 26, 2003
    Publication date: April 22, 2004
    Inventors: Rajiv Ramaswami, Robert R. Ward
  • Publication number: 20040047542
    Abstract: Apparatus and methods are disclosed for alignment of an input mirror and an output mirror in a photonic cross-connect.
    Type: Application
    Filed: March 7, 2003
    Publication date: March 11, 2004
    Inventors: Humair Raza, Robert Ward, Rajiv Ramaswami, Babu Narayanan
  • Publication number: 20040037553
    Abstract: Methods, apparatus and systems for regenerating, monitoring and bridging optical signals through an optical cross-connect switch to provide increased reliability. A self testing method, apparatus and system for an optical cross-connect switch. An optical-to-electrical-to-optical converter (O/E/O) is provided in an optical cross-connect switch to provide optical-electrical-optical conversion. I/O port cards having an optical-to-electrical-to-optical converter are referred to as smart port cards while I/O port cards without an optical-to-electrical-to-optical converter are referred to as passive port cards. Test port/monitor cards are also provided for testing optical cross-connect switches. Methods, apparatus and systems for performing bridging, test access, and supporting redundant optical switch fabrics are also disclosed.
    Type: Application
    Filed: August 28, 2003
    Publication date: February 26, 2004
    Inventors: Rajiv Ramaswami, Robert R. Ward
  • Publication number: 20040008988
    Abstract: Automatic discovery and verification of optical communication links as well as isolation of link failures in an optical communication system.
    Type: Application
    Filed: September 30, 2002
    Publication date: January 15, 2004
    Inventors: Ornan A. Gerstal, Humair Raza, Rajiv Ramaswami, Babu O. Narayanan, Robert Ward, Robert Keys, David Park, Vasant Sahay, Osama Aboul-Magd, Frederic Simard
  • Publication number: 20030223726
    Abstract: One aspect is a method for controllably attenuating the beam of light (108) coupled between incoming and outgoing optical fibers (106) by misaligning minor surfaces (116a, 116b) included of an optical switching module (100). Misalignment of the mirror surfaces (116a and 116b) causes only a portion of the beam of light (108) propagating along the incoming optical fiber (106), which is less than when the light beam deflectors' mirror surfaces (116) are precisely aligned, to propagate along the outgoing optical fiber (108). Thus, the optical switching module (100) controllably attenuates the beam of light (108) coupled between the incoming and the outgoing optical fibers (106). Another aspect is a variable-optical-attenuator (“VOA”) (212) that includes an optically reflective membrane (222) upon which the beam of light (108) impinges.
    Type: Application
    Filed: September 14, 2002
    Publication date: December 4, 2003
    Inventors: Armand P. Neukermans, Rajiv Ramaswami, John F. Heanue, Brian P. Tremaine, Marc Schuman
  • Patent number: 6650803
    Abstract: Methods, apparatus and systems for regenerating, monitoring and bridging optical signals through an optical cross-connect switch to provide increased reliability. A self testing method, apparatus and system for an optical cross-connect switch. An optical-to-electrical-to-optical converter (O/E/O) is provided in an optical cross-connect switch to provide optical-electrical-optical conversion. I/O port cards having an optical-to-electrical-to-optical converter are referred to as smart port cards while I/O port cards without an optical-to-electrical-to-optical converter are referred to as passive port cards. Test port/monitor cards are also provided for testing optical cross-connect switches. Methods, apparatus and systems for performing bridging, test access, and supporting redundant optical switch fabrics are also disclosed.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: November 18, 2003
    Assignee: XROS, Inc.
    Inventors: Rajiv Ramaswami, Robert R. Ward
  • Patent number: 6597826
    Abstract: In one embodiment, a scalable cross-connect switching system and its corresponding method perform a bridging operation by splitting the incoming light signal into at least a first bridged light signal and a second bridged light signal. The first bridged light signal has a power level equal to or substantially greater than a power level of the second bridged light signal. The disproportionate power levels provide low-loss bridging. Light signals based on these bridged light signals are routed through multiple switch fabrics which provide redundancy in case of failure by switching within the switch fabric. To detect failures, a test access port is configured for monitoring multiple optical paths.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: July 22, 2003
    Assignee: XROS, Inc.
    Inventors: Rajiv Ramaswami, Steven Clark, Robert R. Ward
  • Patent number: 6571030
    Abstract: In general, an optical cross-connect switching system comprising a switch subsystem, an input/output (I/O) subsystem including a plurality of removable, I/O port modules, and a switch control subsystem featuring servo modules. These units collectively operate to provide optical data paths for routing of light signals without conversion from optical to electrical domains and back to optical. Also, the optical cross-connect switching system is scalable because the I/O port modules, servo modules and even features of the switch subsystem may be removed without disruption in system operation.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: May 27, 2003
    Assignee: XROS, Inc.
    Inventors: Rajiv Ramaswami, Steven T. Tabaska, Robert R. Ward
  • Publication number: 20020164110
    Abstract: A fiber optic switch (400) includes a fiber optic switching module (100) that receives and fixes ends (104) of optical fibers (106). The module (100) includes numerous reflective light beam deflectors (172) which may be selected as pairs for coupling a beam of light (108) between a pair of optical fibers (106). The module (100) also produces orientation signals from each deflector (172) which indicate its orientation. A portcard (406) included in the switch (400) supplies drive signals to the module (100) for orienting at least one deflector (172). The portcard (406) also receives the orientation signals produced by that deflector (172) together with coordinates that specify an orientation for the deflector (172). The portcard (406) compares the received coordinates with the orientation signals received from the deflector (172) and adjusts the drive signals supplied to the module (100) to reduce any difference between the received coordinates and the orientation signals.
    Type: Application
    Filed: December 1, 2000
    Publication date: November 7, 2002
    Inventors: Arnold P. Neukermans, Timothy G. Slater, Tyler L. Baughman, James P. Dowing, John S. forker, Gregory A. Reznick, Sam Calmes, Steven M. Clark, Jack D. Foster, Marc R. Schuman, Rajiv Ramaswami
  • Patent number: 6445844
    Abstract: A fiber optic switch includes a fiber optic switching module that receives and fixes ends of optical fibers. The module includes numerous reflective light beam deflectors which may be selected as pairs for coupling a beam of light between a pair of optical fibers. The module also produces orientation signals from each deflector which indicate its orientation. A portcard included in the switch supplies drive signals to the module for orienting at least one deflector. The portcard also receives the orientation signals produced by that deflector together with coordinates that specify an orientation for the deflector. The portcard compares the received coordinates with the orientation signals received from the deflector and adjusts the drive signals supplied to the module to reduce any difference between the received coordinates and the orientation signals. The switch also employs optical alignment to precisely orient pairs of deflectors coupling a beam of light between optical fibers.
    Type: Grant
    Filed: December 21, 1999
    Date of Patent: September 3, 2002
    Assignee: XROS, Inc.
    Inventors: Armand P. Neukermans, Timothy G. Slater, Tyler L. Baughman, James P. Downing, John S. Forker, Gregory A. Reznick, Sam Calmes, Steven M. Clark, Jack D. Foster, Marc R. Schuman, Rajiv Ramaswami
  • Publication number: 20010043563
    Abstract: Efficient methods for rerouting failed channels on to spare channels in a multichannel transmission system are described. One method uses a minimal amount of rerouting to reroute all the channels if one or two line cards fail.
    Type: Application
    Filed: May 4, 2001
    Publication date: November 22, 2001
    Inventors: Ornan Alexander Gerstel, William Eric Hall, Rajiv Ramaswami, Galen Hajime Sasaki
  • Patent number: 6256293
    Abstract: Efficient methods for rerouting failed channels on to spare channels in a multichannel transmission system are described. One method uses a minimal amount of rerouting to reroute all the channels if one or two line cards fail. Another set of methods reroute up to two failed channels on to spare channels in the event of channel failures. With this method only the failed channels are rerouted. However the failed channels may have to be routed through a slightly larger, but minimal, number of additional hops than with the first method.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: July 3, 2001
    Assignee: Tellabs Operations, Inc.
    Inventors: Ornan Alexander Gerstel, William Eric Hall, Rajiv Ramaswami, Galen Hajime Sasaki
  • Patent number: 6108311
    Abstract: A ring communication network including N nodes and comprising links between the nodes for carrying data in W channels. The network is configured by providing nodes and channels such that N.gtoreq.2 log.sub.2 W-1 where W is a power of 2. No more than W channels are assigned to the transmission of data along any of the links. The nodes are configured such that each channel of a first one of the links adjacent any one of the nodes can be switched to no more than W-1 channels of a second one of the links adjacent any one node.
    Type: Grant
    Filed: April 29, 1996
    Date of Patent: August 22, 2000
    Assignee: Tellabs Operations, Inc.
    Inventors: Rajiv Ramaswami, Galen Sasaki
  • Patent number: 5867289
    Abstract: A fault detecting apparatus and method for a network node of an optical transmission system receives a wavelength division multiplexed (WDM) optical signal which includes a group of optical channels. The network node includes an optical demultiplexer, optical switch, optical multiplexer, and an optical channel add/drop device. Supervisory optical signals having a different wavelength than the wavelengths of the group of optical channels are generated and spliced with each optical channel by the optical demultiplexer. The supervisory channel optical power is tapped off at various points in the network node, such as the output optical channels of the demultiplexer, dropped optical channel outputs, output optical channels from the optical switch, and the output WDM optical signal of the multiplexer. The supervisory channels are monitored by a wavemeter for bypass lightpaths and dropped lightpaths.
    Type: Grant
    Filed: December 24, 1996
    Date of Patent: February 2, 1999
    Assignee: International Business Machines Corporation
    Inventors: Ornan Alexander Gerstel, Chung-Sheng Li, Rajiv Ramaswami, Chaoyu Yue