Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A semi-analytic numerical method and one software reduction to practice of a means of finding the eigenmodes of optical fiber that has cylindrical symmetry. This includes fibers that have a radially varying index of refraction that can be described or approximated by one or more cylindrical layers of constant index of refraction.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Apparatus and methods for accessing data on a multilayered optical storage medium. The apparatus uses the time-of-flight of illumination directed to and reflected by the layers of the optical medium to access data stored on a desired layer of the medium. More particularly, alterations in illumination reflected from the desired layer are detected to access data stored on the layer. In accordance with embodiments of the invention utilizing interferometric techniques, the time-of-flight of a reference illumination is adjusted to cause interference of the reference illumination with the illumination reflected from the layer which contains the data to be accessed. Alternatively, and in accordance with embodiments of the invention utilizing non-interferometric techniques, the time-of-flight of illumination reflected by the layer which contains the data to be accessed is selected to permit data stored on the desired layer to be accessed.

Abstract: Apparatus and methods for reading multilayer optical data storage media are described. The apparatus includes a short coherence length light source and an optical system. The optical system focuses the light from the source onto the layers of the storage media. The coherence length of the source is less than 100 microns or less than the spacing between the layers. The Rayleigh range within the storage media may also be less than the spacing between the layers. The apparatus may include a detector for measuring alterations in light reflected from each layer of the storage media caused by data. The source may be any short coherence length source including superluminescent diodes, mode locked lasers, multi-longitudinal mode laser diode, or rare earth doped amplified spontaneous emission sources.