The Boeing Company

Terabeam Corporation

Pertex Telecommunication LLC

John A Bell

Barbara A Capron

Herman M Presby

Robert M Pierce

John J Schuster

David A Leep

Ronald L Hagman

Michael De La Chapelle

James Stocker Webb

David Christien Soreide

William D Sherman

Nicholas Eichhorn Bratt

David W Rush

Paul Frederic Sjoholm

John A McGarvey

William R Babbitt

Mark Lewis Plett

Michael C Hamilton

Peter J deGroot

W Randall Babbitt

David Rush

Carrie Sjaarda Cornish

Carrie Jean Sjaarda

Stuart Ferrier

An apparatus for transmission of free space optical communication system signals employing a spatially-extended light source and method of using the same. A laser beam source directs an optical signal into a free end of a segment of multimode fiber. As the optical signal passes through the segment of multimode fiber, the optical signal is converted into a mode-scrambled optical signal. This mode-scrambled signal may then be used as a spatially-extended light source that is directed outward as an optical beam through the use of a collimating lens.

Extended source transmitter for free space optical communication systems

A method and apparatus for encoding data. A first pair of optical signals having a first phase difference is generated in response to receiving an input signal having a voltage. A second pair of optical signals having a second phase difference is generated in response to receiving an input signal having a voltage. The first pair of optical signals is combined to form a first optical signal having a first intensity. The second pair of optical signals is combined to form a second optical signal having a second intensity. The first intensity of the first optical signal reaches a peak at a different time from the second intensity of the second optical signal.

Optical sampling method for analog to digital conversion

Systems, methods, and computer program products are provided for accurately measuring frequency-and/or-phase-related parameters of a sinusoidal signal that varies non-linearly in frequency or phase. A sinusoidal signal is sampled over a finite period of time at a plurality of sample points. The sampled signals are pre-processed, and a Fourier transform is performed on the pre-processed sampled signals. Phases of the pre-processed sampled signals are extracted from the Fourier transform, and a measurement indicative of frequency of the sinusoidal signal is determined from slope of the phases of the pre-processed sampled signals. Range to a target may be determined using the exemplary signal processing described above on laser radar interference signals.

Ultra-linear signal processing for radar and laser radar

A system for providing wireless communication within a local area network (LAN) onboard a mobile platform. The system includes at least one seat transceiver located in a passenger seating area, and at least one passenger service unit (PSU) located above the passenger seating area. The PSU includes at least one PSU transceiver. Additionally, the system includes a direct path infrared (IR) signal transmission link between the seat transceiver and the PSU transceiver. The direct path IR transmission link transmits data between the seat transceiver and the PSU transceiver.

Mobile platform local area network using direct infrared

Apparatus and methods for implementing a high-power or high-sensitivity tracking mode of operation in a free-space optical communication system are disclosed. Functions of the high-power or high-sensitivity tracking mode may be implemented in response to one or more engage signals generated and transmitted in response to a sensed inclement weather condition, such as fog or the like, which may interfere with communication of an optical signal between a pair of free-space optical terminals in the free-space optical communication system. Implementation of the high-power or high-sensitivity tracking mode facilitates maintenance of the alignment between the pair of free-space optical terminals throughout the duration of the inclement weather condition to allow data communication to resume fully after the inclement weather condition has diminished.

High-sensitivity tracking in free-space optical communication systems

An optical fiber assembly includes an optical fiber and ferrule. The ferrule's face is partitioned into several regions. Optical elements can be formed on the regions to diffract light incident on the ferrule. Alternatively, the ferrule's face may have several reflective facets. Light incident on the end of the optical fiber propagates to a communications detector. Light incident on the ferrule's face is redirected to tracking detectors, each arranged to receive the redirected light from a preselected region of the ferrule. The output signals of the tracking detectors are used to adjust the alignment between the incident light and the assembly. Alternatively, tracking fibers or a quadrant cell may be used to directly receive light that would otherwise be incident on the ferrule's face.

Free space optical system with multiple function detectors

An optical tracking system for use in an optical receiver of an optical communication system includes a first focus unit, a tracker, and an optical fiber having an angled tip. The first focus unit receives an optical signal to be tracked and focuses it on the angled tip of the fiber. The fiber is connected to a communications detector of the optical communication system. In addition, the angled tip of the fiber reflects a portion of the focused optical signal to the tracker. The tracker processes the reflected portion of the optical signal to correct for any misalignment between the optical signal and the optical receiver.

Optical tracking system with reflective fiber

A baffle containing a plurality of small apertures is mounted on the receiver aperture of an optical receiver, such as a wireless optical telecommunication system receiver. The baffle attenuates ambient radiation that may interfere with the optical receiver. The baffle includes a plurality of apertures that have their axes substantially parallel to the optical axis of the receiver.

Optical receiver having baffle including a plurality of apertures

A heterodyne interferometer and an associated interferometric method are provided that significantly reduce polarization crosstalk and that permit the target to translate to a limited extent in a direction orthogonal to the direction of interest and to be tilted to a limited extent without adversely affecting the resulting measurement. The heterodyne interferometer includes a beamsplitter for splitting each of a first beam and a coherent second beam into at least two partial beams. Advantageously, the first beam and the partial first beams propagate in a first plane, while the second beam and the partial second beams propagate in a second plane that is offset from the first plane by at least two beam diameters so as not to spatially overlap with the first beam and the partial first beams, thereby preventing polarization crosstalk. The heterodyne interferometer also includes a reference arm and a measurement arm that each receive a partial first beam and a partial second beam. The measurement arm can include a pair of crossed porro prisms with at least one of the porro prisms being adapted to move in conjunction with the target. By utilizing the pair of crossed porro prisms, the target can translate to a limited extent in a direction orthogonal to the measurement path and can be tilted to a limited extent without adversely affecting the resulting measurements. The heterodyne interferometer can also include at least one and, more commonly, a pair of detectors for receiving partial beams that have traversed the reference arm and the measurement arm. Based upon the resulting interference fringes, the detector can provide a signal indicative of the target displacement.

Hetrodyne interferometer and associated interferometric method

The invention performs coordinate measurement employing multiple-frequency intensity-modulated laser radar. A laser diode source is intensity modulated by variation of its excitation current. Its output beam is directed to a target using scanning mirrors or other opto-mechanical means, and the light returned from the target is detected. The modulation frequency is alternated between two or more values, creating a dataset of several relative phase measurements that uniquely determine the distance to the target without ambiguity. A device for carrying out such a method includes a laser whose output is modulated by a high frequency signal generator, optics for directing the output signal to the target to a detector, a signal generator which generates reference signals offset in frequency from the intensity modulation frequencies by a predetermined amount; mixers for combining the return signals with the reference signals to form a first set of intermediate frequency signals, and for combining the modulation signals with the reference signals to form a second set of intermediate frequency signals, and a computer which calculates phase differences between the output beam and the return signals for each modulation frequency from the intermediate frequencies, and determines the distance to the target from the phase differences.

Method and apparatus for measuring distance to a target

An electromagnetic signal processor which uses an inhomogeneously broadened absorbing material to store data for long periods of time and which is able to process an uninterrupted signal. A spectral interference pattern created by the interference of at least two input pulses of electromagnetic radiation is stored in the absorbing medium. The pattern is fixed in the medium to allow for uninterrupted processing of signal data. The fixed pattern employed in such a processor could be reprogrammed by either reversing the gating process used to program the absorbing medium or by spatially directing the electromagnetic beams to a different portion of the material.

Optical signal processor for processing continuous signal data

An electro-optical analog-to-digital converter having an enhanced effective sample rate. Several embodiments of the electro-optical analog-to-digital converter (10, 100, 150, and 200) are described, each involving either space-division demultiplexing, time-division demultiplexing, or wavelength-division demultiplexing to increase the effective sample rate at which an analog signal provided by a source (36) can be converted to a digital signal using electrical analog-to-digital converters (66). A plurality of light pulses having a constant amplitude are modulated in response to the analog signal and demultiplexed using one of the three different techniques, so that the analog signal is sampled at successive points in time, varying the intensity of light pulses passing through each modulator channel (32, 104). In the space-division demultiplexing approach, light pulses produced by a mode-locked diode laser (12) are split into a plurality of channels and delayed by different time intervals so that the replicated pulses are spaced apart in time prior to being modulated by passage through a modulator array (32). The demultiplexed and modulated light pulses are input to a plurality of photodetectors (56) amplified by a plurality of amplifiers (60 ), and input to a plurality of electrical analog-to-digital converters (64). In the time-division multiplexing approach, either discrete optical switches (108) or an optical switch array (158) is used to transmit successive modulated light pulses into selected photodetectors for conversion to an electrical signal that is input to the analog-to-digital converters. The wavelength-division multiplexing approach uses a plurality of mode-locked diode lasers (210), each having a different characteristic wavelength. Pulses output from the mode-locked diode lasers are generated at different times and provided to a wavelength-division multiplexer (214) where they are combined and input to the modulator. A wavelength-division demultiplexer (220) separates the different wavelength pulses for input to selected photodetectors. For all the embodiments, the effective sample rate corresponds to the number of channels multiplied by the rate at which pulses are produced by the mode-locked laser diodes.

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Issaquah, WA, United States of America

John A Bell