Patents by Inventor Boris Stefanov

Boris Stefanov 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: 20120134663
    Abstract: A reflector assembly is disclosed that may include a housing; a fiber stud disposed within the housing; a filter lens having an OTDR reflective layer, the filter lens located downstream from the fiber stud and receiving light energy from the fiber stud, and configured to be transparent for light within a communication wavelength band and reflective within a diagnostic wavelength band.
    Type: Application
    Filed: November 29, 2010
    Publication date: May 31, 2012
    Inventors: Hongsheng Wang, Richard Chen, Zemer Mizrahi, Ali Ouali, Boris Stefanov
  • Patent number: 7633674
    Abstract: A photonic integrated circuit having a plurality of circuit components, is disclosed, which may include an MMI for splitting signal power passing therethrough among first and second optical pathways coupled to first and second outputs, respectively, of the MMI, thereby directing first and second percentages of the signal power along the first and the second optical pathways, respectively; and a photodetector integrated into the photonic integrated circuit and coupled to said first optical pathway for measuring a signal power level on said first optical pathway.
    Type: Grant
    Filed: October 20, 2008
    Date of Patent: December 15, 2009
    Assignee: Alphion Corporation
    Inventors: Mohammad Laham, Boris Stefanov
  • Publication number: 20090041454
    Abstract: A photonic integrated circuit having a plurality of circuit components, is disclosed, which may include an MMI for splitting signal power passing therethrough among first and second optical pathways coupled to first and second outputs, respectively, of the MMI, thereby directing first and second percentages of the signal power along the first and the second optical pathways, respectively; and a photodetector integrated into the photonic integrated circuit and coupled to said first optical pathway for measuring a signal power level on said first optical pathway.
    Type: Application
    Filed: October 20, 2008
    Publication date: February 12, 2009
    Applicant: Alphion Corporation
    Inventors: Mohammad Laham, Boris Stefanov
  • Patent number: 7440179
    Abstract: The method of isolating faults internal to, for example, from tonic integrated circuits by diverting a portion of certain input and output signals to integrated photo detectors. By analyzing the admitted optical signal in each of plural photo detectors, falls within the circuit can be isolated.
    Type: Grant
    Filed: May 28, 2003
    Date of Patent: October 21, 2008
    Assignee: Alphion Corporation
    Inventors: Mohammad Laham, Boris Stefanov
  • Patent number: 7319555
    Abstract: Monitoring of the input power is performed on-chip and is used to monitor and maintain performance, detect failure and trigger network protection strategies. An optical power-monitoring technique uses a photodetector monolithically integrated with the semiconductor optical amplifier—Mach-Zehnder interferometer circuit to monitor the P2R device and keep the output stable while the input power varies.
    Type: Grant
    Filed: April 27, 2006
    Date of Patent: January 15, 2008
    Assignee: Alphion Corporation
    Inventors: Ganesh Lakshminarayana, Ruomei Mu, Hongsheng Wang, Jithamithra Sarathy, Boris Stefanov
  • Patent number: 7239768
    Abstract: A integrated optical circuit comprises an interferometer having a first optical path and a second optical path configured for regenerating an input signal entering the first path by interference at a first coupler between continuous wave (CW) signals from the two optical paths, and a third optical path configured such that a canceling signal passing therethrough cancels, at a second coupler, a traveling signal from the first arm. When the device is operated in a counter-propagative mode, the traveling signal is the CW signal from the first arm. When the device is operated in a co-propagative mode, the traveling signal is the input signal from the first arm.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: July 3, 2007
    Assignee: Alphion Corporation
    Inventors: Ganesh Lakshminarayana, Jithamithra Sarathy, Boris Stefanov
  • Patent number: 7190909
    Abstract: Method and apparatus are presented for the generation and detection of maintenance signals in an optical data network. The maintenance signals are such that they can be read both by high bit-rate and low bit-rate receivers. Detection of the maintenance signals occurs in two stages. In a low bit-rate first stage each nodal input port is sampled in a round robin fashion to detect the presence of a maintenance signal. In a high bit-rate second stage the maintenance signal is verified and read by a high speed receiver, along with other high bit-rate information transmitted with it. One second stage high speed receiver is shared among M input channels for cost and circuit efficiency.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: March 13, 2007
    Assignee: Alphion Corporation
    Inventors: Jayanta Das, Ganesh Lakshminarayana, Kuo-Ming Lee, Roman Antosik, Scott Kaminski, Jithamithra Sarathy, Boris Stefanov, Ronald Simprini, Bharat Dave
  • Publication number: 20070008613
    Abstract: Monitoring of the input power is performed on-chip and is used to monitor and maintain performance, detect failure and trigger network protection strategies. An optical power-monitoring technique uses a photodetector monolithically integrated with the semiconductor optical amplifier—Mach-Zehnder interferometer circuit to monitor the P2R device and keep the output stable while the input power varies.
    Type: Application
    Filed: April 27, 2006
    Publication date: January 11, 2007
    Inventors: Ganesh Lakshminarayana, Ruomei Mu, Hongsheng Wang, Jithamithra Sarathy, Boris Stefanov
  • Publication number: 20060182440
    Abstract: A robust nonblocking switch architecture is presented, in the first and final stages made of switch modules which have extra, unallocated, input and output ports beyond those necessary to render the switch architecture nonblocking. Each middle stage has an extra switch module, affording it spare unallocated ports as well. A method of isolating a fault is also presented, given the robust switching architecture. Operating on each stage one at a time, the switching architecture is reconnected so as to bypass either the input, the output, or both the input and the output ports of the switch module in such stage impacted in the faulted signal path. Such method allows the isolation of the faulty switch module, and can be done automatically, with either external apparatus, or integrated fault isolation equipment.
    Type: Application
    Filed: April 18, 2006
    Publication date: August 17, 2006
    Inventors: Boris Stefanov, Mohammad Laham, Kevin Beach, Scott Kaminski
  • Patent number: 7009210
    Abstract: A method and apparatus for a tunable optical spectrum analyzer that can measure the optical spectrum of a demultiplexed DWDM signal are presented. The signal level and Optical Signal to Noise Ratio (OSNR) of an individual channel of the DWDM signal can be obtained from the measured optical spectrum. The device employs a rapid tuning and detection technique to obtain the optical spectrum of the incoming signal. In a preferred embodiment the apparatus is fabricated on a single chip resulting in a compact measurement device. Using the device of the preferred embodiment, single channel OSNR can be determined in as small a time interval as approximately 225 microseconds. Using an array of these devices an entire DWDM mixed signal can be monitored as to OP and OSNR in the same time interval.
    Type: Grant
    Filed: May 9, 2001
    Date of Patent: March 7, 2006
    Assignee: Alphion Corporation
    Inventors: Jithamithra Sarathy, Chinnabbu Ekambaram, David Lidsky, Bharat Dave, Boris Stefanov, Tan B. Thai, Ronald Simprini, Julio Martinez, Gaurav Naik
  • Publication number: 20060018587
    Abstract: A integrated optical circuit comprises an interferometer having a first optical path and a second optical path configured for regenerating an input signal entering the first path by interference at a first coupler between continuous wave (CW) signals from the two optical paths, and a third optical path configured such that a canceling signal passing therethrough cancels, at a second coupler, a traveling signal from the first arm. When the device is operated in a counter-propagative mode, the traveling signal is the CW signal from the first arm. When the device is operated in a co-propagative mode, the traveling signal is the input signal from the first arm.
    Type: Application
    Filed: June 2, 2005
    Publication date: January 26, 2006
    Inventors: Ganesh Lakshminarayana, Jithamithra Sarathy, Boris Stefanov
  • Patent number: 6856767
    Abstract: The present invention provides an optical signal quality selection system for optimizing the quality of information transmission. The system splits an incoming optical signal into two equal signals. The split signals are evaluated in optical performance monitors, transmitting an electrical output message to a signal selector relating to the quality of the respective signal. A second electrical message is sent from the optical performance generator to an alarm indicator signal generator, which sends an optical signal to the signal selector to drop the one of the split signals and transmit the non-dropped split signal. An unequipped optical signal from an optical idle signal generator is triggered if no active optical signal is being transmitted.
    Type: Grant
    Filed: April 18, 2001
    Date of Patent: February 15, 2005
    Assignee: Alphion Corporation
    Inventors: Mohammad Laham, Raj Acharya, Roman Antosik, Jayantha Das, Bharat Dave, Chinnabbu Ekambaram, Khem Gandhi, Frank Hujber, David Lowe, Frederick Renner, Jiten Sarathy, Ronald Simprini, Boris Stefanov, Tan Thai, Ravi Vora
  • Publication number: 20040100257
    Abstract: An Abstract was inadvertently omitted from the original filing of the application back on May 28, 2003, and we ask that you kindly add the following paragraph at the end of the application: “The method of isolating faults internal to, for example, from tonic integrated circuits by diverting a portion of certain input and output signals to integrated photo detectors. By analyzing the admitted optical signal in each of plural photo detectors, falls within the circuit can be isolated.
    Type: Application
    Filed: May 28, 2003
    Publication date: May 27, 2004
    Inventors: Mohammad Laham, Boris Stefanov
  • Patent number: 6727991
    Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: April 27, 2004
    Assignee: Alphion Corporation
    Inventors: Julio Martinez, Kwang Kim, Olga Nedzhvetskaya, Doruk Engin, Jiten Sarathy, Roman Antosik, Bharat Dave, Michael Evans, David Lidsky, Ronald Simprini, Boris Stefanov, Tan Thai
  • Patent number: 6724484
    Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: April 20, 2004
    Assignee: Alphion Corporation
    Inventors: Julio Martinez, Kwang Kim, Olga Nedzhvetskaya, Doruk Engin, Jiten Sarathy, Roman Antosik, Bharat Dave, Michael Evans, David Lidsky, Ronald Simprini, Boris Stefanov, Tan Thai
  • Patent number: 6678086
    Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: January 13, 2004
    Assignee: Alphion Corporation
    Inventors: Bharat Dave, Doruk Engin, Kwang Kim, Mohammad Laham, Julio Martinez, Olga Nedzhvetskaya, Jithamithra Sarathy, Ronald Simprini, Boris Stefanov, Tan Buu Thai
  • Patent number: 6671467
    Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: December 30, 2003
    Assignee: Alphion Corporation
    Inventors: Bharat Dave, Doruk Engin, Kwang Kim, Mohammad Laham, Julio Martinez, Olga Nedzhvetskaya, Jithamithra Sarathy, Roanld Simprini, Boris Stefanov, Tan Buu Thai
  • Patent number: 6646794
    Abstract: A method and circuit are presented for an all-optical format independent preprocessor that processes an arbitrary optical input signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. The method involves subtracting a delayed copy of the signal from the original, thereby effectively doubling its frequency, and inserting a pulse at each transition of the original signal, whether rising or falling. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The asymmetry consists of a delay element in one arm. In a preferred embodiment the entire device is fabricated on a semiconductor substrate, allowing for compactness as well as minimization of interconnectivity losses and overall power consumption. The output of the preprocessor, having a significant frequency component at its original clock rate, can then be fed to a clock recovery stage for all-optical clock recovery.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: November 11, 2003
    Assignee: Alphion Corporation
    Inventors: Julio Martinez, Kwang Kim, Olga Nedzhvetskaya, Doruk Engin, Jiten Sarathy, Bharat Dave, Ronald Simprini, Boris Stefanov, Tan Thai
  • Patent number: 6636318
    Abstract: A method and system for AO3R functionality is presented. The system includes an AO2R device followed by an AOCR clock recovery module and an AOR retiming device. The AOR retiming device takes as input a recovered clock signal extracted from the output of the AO2R by the AOCR clock recovery module. The output is the recovered clock signal gated by the regenerated and reshaped input signal, and a monitor circuit is used to set the optimum operations of the retiming device. In a first embodiment the output of the AOR retiming device is fed to an AOC code and wavelength conversion output stage, which returns the signal to the NRZ coding, on a service wavelength converted to match the fixed wavelength connection with the DWDM transmission system. In a second embodiment the code conversion is incorporated into the AOR retiming device, and wavelength conversion is accomplished in the AOCR clock recovery device.
    Type: Grant
    Filed: October 5, 2001
    Date of Patent: October 21, 2003
    Assignee: Alphion Corp.
    Inventors: Jithamithra Sarathy, Bharat Dave, Boris Stefanov, Ronald Simprini, Tan B. Thai, Roman Antosik, Aleksandr Miglo, Olga Nedzhvetska, Kwang Kim, Doruk Engin
  • Patent number: 6624924
    Abstract: A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: September 23, 2003
    Assignee: Alphion Corp.
    Inventors: Bharat Dave, Doruk Engin, Kwang Kim, Mohammad Laham, Julio Martinez, Olga Nedzhvetskaya, Jithamithra Sarathy, Ronald Simprini, Boris Stefanov, Tan Buu Thai