Massachusetts Institute of Technology

US Government As Represented by the Secretary of the Army

Network Appliance, Inc.

Netapp, Inc.

Stephen R Chinn

Muriel Medard

Lew Goldberg

Eric Arthur Swanson

James N Walpole

John D Moores

Christine A Wang

Michael James Rydeen

Salil A Parikh

Mark R Parquette

Gene M Ciancaglini

James A Hart

Michael M Garofalo

Emily S Kintzer

Guy Oliveira

William Proulx

Donald Proulx

Michael Lupinacci

Paul Marichal

Leo J Missaggia

Joseph P Donnelly

Bradley W Libbey

Steven Lumetta

James K Roberge

James D Haberstat

Philip A Lee

Albert Fenner Milton

Lee J Missaggia

An optical detector array is disclosed to locate dynamically the source position of an incoming beam of light. For example, the incoming beam of light may be a reflection of a low-divergence laser beam from a scattering surface in target space. A system and a method are disclosed for determining the position of a light spot generated by an optical beam when it falls on a scattering surface based on a one-dimensional detector array.

Two-dimensional optical spot location using a one-dimensional detector array

A system for short-range laser detection and ranging of targets can provides rapid three-dimensional, e.g., angle, angle, range, scans over a wide field-of-view. Except for the final transmit/receive lens, the disclosed LADAR system can be implemented in an all-fiber configuration. Such system is compact, low cost, robust to misalignment, and lends itself to eye-safe operation by making use of available pulsed 1550 nm fiber lasers and amplifier sources. The disclosed LADAR system incorporates many novel features that provide significant advantages compared to current LADAR systems. The disclosed system uses a monostatic fiber-based transmitter/receiver, a fiber beam scanner based on a laterally vibrating fiber, and a position sensor to monitor the transmitted beam position.

Compact fiber-based scanning laser detection and ranging system

A compact monostatic optical transmitter/receiver device simultaneously transmits an optical beam and collects returning light using a single lens or optical aperture. The system provides automatic alignment of the transmit and receive aperture and is compatible with fiber-coupled laser sources. Transmit light is emitted from a double-cladding fiber core while received light is coupled into the inner cladding of the same fiber. The transmit light propagating in the core and the received light propagating in the inner cladding are separated by the means of a diplexer comprised of a fused fiber coupler or a fiber-coupled micro-optic device.

Compact monostatic optical receiver and transmitter

High-resolution optical position sensing is disclosed using sparse, low-resolution detectors. Precise location of two-dimensional position or angular orientation of an optical beam at the focal plane of a sensor system is made possible using sparse low-resolution detectors. The beam may be emitted directly from a source, or scattered from a remote target. The high precision in determining the beam or focal spot location is the result of a novel data processing and analysis method for the signals from the low-resolution detectors.

High-resolution optical position sensing with sparse, low-resolution detectors

An apparatus and method for non-determination of the surface velocity of a target using optical interference and Doppler shifting of the light reflected from the target are disclosed. It may be used to measure small-amplitude, acoustic frequency surface vibrations as well as non-periodic surface vibration.

Fiber-optic, digital system for laser Doppler vibrometers (LDVs)

A method and apparatus for a communications network that executes a medium access control (MAC) protocol that permits multiple access to a shared medium or shared switching fabric. The MAC protocol uses a BANDWIDTH_ALLOCATOR to regulate access to the network by sending a permission message to a NODE, allowing it to transmit to a specific set of NODEs for a specific length of time. The medium and switching fabric can carry one or more protocols, each of varying framing format and native bitrate. The switching fabric provides a connection-oriented bufferless data transport service that preserves frame ordering. An illustrative embodiment uses a slotted master/slave time-division multiplexed access (TDMA) scheme to allow flexible provisioning of network bandwidth.

Multi-protocol network interface card

A method and apparatus for a communications network that executes a medium access control (MAC) protocol that permits multiple access to a shared medium or shared switching fabric. The MAC protocol uses a bandwidth allocator to regulate access to the network by sending a permission message to a node, allowing it to transmit to a specific set of nodes for a specific length of time. The medium and switching fabric can carry one or more protocols, each of varying framing format and native bitrate. The switching fabric provides a connection-oriented bufferless data transport service that preserves frame ordering. An illustrative embodiment uses a slotted master/slave time-division multiplexed access (TDMA) scheme to allow flexible provisioning of network bandwidth.

Integrated system and method for controlling telecommunication network data communicated over a local area network and storage data communicated over a storage area network

Systems and methods for regulating optical power are described. A system for regulating optical power includes a laser driver circuit that receives an enable/disable signal and a data modulator input. The enable/disable signal regulates asynchronous mode operation. The system also includes a laser module including a laser diode emitter and a photodiode detector. The laser module is coupled to the laser driver circuit and receives a laser bias current from the laser driver circuit. The system also includes a switch coupled to the photodiode to receive a signal from the photodiode detector. The system also includes an automatic power control (APC) feedback circuit that receives a signal from the switch and provides a laser bias current feedback signal to the laser driver circuit to compensate for power output changes in the laser diode emitter over time.

System for regulating optical output power

A laser and optical amplifier waveguide device with a plurality of layers that supports a single lowest-order optical mode with gain while higher order modes radiate and have a net loss. The supported lowest-order mode which has gain, has a mode cross section which is large compared to the operating optical wavelength in both the transverse and lateral directions. The contours of constant optical intensity of such lowest-order can be nearly circular, having an approximately elliptical shape with a small aspect ratio.

Stab-coupled optical waveguide laser and amplifier

Apparatus and techniques for detecting malfunctions, anomalies and attacks upon optical devices of a transparent all-optical network, including amplified links and optical nodes, of the network. A portion of an input signal of the optical device and a portion of an output signal from the optical device are coupled to an optical processing unit and a an optical to electrical signal converter. The electrical output signal of the converter is coupled to an electronic processing unit which generates a difference signal which is a function of the input and output signal portions for comparison to a predetermined set of parameters. The result of the comparison is an alarm signal indicative of the occurrence of a malfunction. Also described is an optical comparator capable of generating the difference signal which is indicative of perturbations in the optical device.

Method and apparatus for detecting malfunctions in communication systems

Apparatus and techniques for detecting malfunctions, anomalies and attacks upon optical devices of a transparent all-optical network, including amplified links and optical nodes of the network. A portion of an input signal of the optical device and a portion of an output signal from the optical device are coupled to an optical processing unit and a an optical to electrical signal converter. The electrical output signal of the converter is coupled to an electronic processing unit which generates a difference signal which is a function of the input and output signal portions for comparison to a predetermined set of parameters. The result of the comparison is an alarm signal indicative of the occurrence of a malfunction. Also described is an optical comparator capable of generating the difference signal which is indicative of perturbations in the optical device.

Method of performing OFDR on a sample comprising steps of: providing an external-cavity frequency-tuned laser having an optical cavity of effective length; tuning the laser to generate a change in wavelength; changing the effective length of the optical cavity proportionally to the change in wavelength so as to tune the longitudinal cavity mode frequency at the same rate as the wavelength is changed; directing light from the laser onto the sample; receiving light reflected from the sample; combining light reflected from the sample with light from the external-cavity frequency-tuned laser; detecting the combined light and generating a beat signal in response thereto; and performing digital signal processing to extract spatial information about the sample in response to the detected beat signal. An OFDR system is also disclosed comprising: a laser comprising an output port; an optical ring having a round trip time, a center frequency and a broad-bandwidth gain medium; a wavelength selecting device in optical communication with the gain medium; a frequency shifter in optical communication with the gain medium and the wavelength selecting device; and an optical coupler in optical communication with the optical gain medium, the wavelength selecting device, and the frequency shifter. The optical coupler couples light from the optical ring to the output port, wherein the wavelength selecting device tunes the center wavelength at a rate equal to the incremental change in frequency caused by the frequency shifter divided by the round trip time of the optical ring thereby providing nearly continuous frequency sweep.

Method and apparatus for performing optical frequency domain

An optical system, in one embodiment including an external-cavity frequency-tuned laser having a tunable longitudinal cavity mode and a center tunable wavelength. The external-cavity frequency-tuned laser includes an optical cavity, an optical gain medium positioned within the optical cavity, and a rapid tuning wavelength selecting device positioned to receive light from the optical gain medium and adapted to return selected wavelengths of light to the optical gain medium. The external-cavity frequency-tuned laser is substantially continuously tunable and the tunable wavelength selecting device tunes the center wavelength of the external-cavity frequency-tuned laser at the same rate as the longitudinal cavity mode of the external-cavity frequency-tuned laser is tuned. In another embodiment the optical system includes an interferometer in optical communication with the external-cavity frequency-tuned laser. The interferometer is adapted to project a portion of light from the external-cavity frequency-tuned laser onto a sample, to receive light altered by the sample, and to combine light reflected from the sample and the light from the external-cavity frequency-tuned laser. A detector positioned to receive the combined light from the interferometer and to generate a signal in response thereto. A processing unit in communication with the detector performs digital signal processing to extract spatial information related to the sample in response to the signal from the detector.

Growing community of inventors

Alexandria, VA, United States of America

Stephen R Chinn