USA As Represented by Secretary of the Navy

Broadband Royalty Corporation

3 Phoenix, Inc.

Halliburton Energy Services, Inc.

Optinel Systems, Inc.

Welldynamics, B.v.

Todd, Michael D.

Leblanc, Michael

Gregg A Johnson

Bryan L Althouse

Sandeep T Vohra

Joseph Murray

Michael D Todd

Greg Nau

Neal Gregory Skinner

John R Dennis

Thomas L Carroll

Chia-Chen Chang

Evelyn Boettcher

Michel Joseph Leblanc

John Jamieson

Sylvan I Caplan

Michel Leblanc

Michael Leblanc

Improved laser sensors () employing doped laser crystals () for transducing output proportional to forces impinging upon the sensors. The disclosed sensors are compact, low powered and may be constructed relatively inexpensively from readily available materials. The disclosed sensors eliminate the need for costly, optical power-sapping fiber connections at the laser crystals. According to certain embodiments, the disclosed sensors are configured for local recovery of output signals using conventional digital telemetry. According to other embodiments, the sensors generate output through a dense wavelength division multiplexing (DWDM) laser (), thereby allowing remote recovery without the need for frequency division multiplexing and issues involved with preloading the sensors to produce beat frequencies in unique bands.

Compact laser sensors and monitoring systems including such sensors

The present invention is an apparatus, method and system for time synchronizing data from various sensor types that enables data fusion and transport. To provide this capability, the present invention utilizes an inverted Passive Optical Network (PON) approach for synchronous communication. Further, the present invention introduces an inverted Passive Electrical Network (iPEN) that extends the iPON approach. Data that are in a common format with embedded time synchronization information can easily be integrated or fused and transported over such communication links. The present invention provides the ability to merge and aggregate data from a wide range of disparate sensors and systems while maintaining close synchronization. The present invention is appropriate for synchronization of data, voice, and video onto a single network and/or multi-tiered networks and can also handle signal processing and control technologies at line rates well into the Gigabits per second (Gbps) range.

Inverted passive optical network/inverted passive electrical network (iPON/iPEN) based data fusion and synchronization system

An optical channel monitor is described, the optical channel monitor includes an optical input port, a photodetector disposed in an optical path communicating at least intermittently with the optical input port, an optical filter disposed in the optical path between the optical input port and the photodetector, and an optical band splitter disposed in the optical path between the optical filter and the photodetector. The optical filter is a multibandpass filter, such as a scanning Fabry-Perot filter. The optical channel monitor also comprises a reference light system for providing a calibration standard against which an optical signal input through the input port may be compared. The channel monitor finds application in optical transmission systems including wavelength division multiplexed (WDM) optical communication systems.

Optical channel monitor utilizing multiple Fabry-Perot filter pass-bands

A well pressure and temperature measurement system and method are provided. In a described embodiment, a sensor system includes multiple strain sensors attached to a structure which changes dimensionally in response to well pressure and temperature changes. The strain sensors may be fiber optic sensors. The structure may be tubular and the strain sensors may detect axial and hoop strains in the structure.

Subterranean well pressure and temperature measurement

A tunable dispersion compensating device for optical communications systems has a compliant support block having a longitudinal axis and a load-receiving surface oriented substantially parallel to the longitudinal axis. The load receiving surface is suitable to receive an applied load in a direction substantially orthogonal to the longitudinal axis. A Bragg-grating fiber is disposed in the compliant support block and extends substantially along, and at an angle to, the longitudinal axis of the compliant support block.

Tunable dispersion compensating bandwidth device for fiber optics system

A passive, temperature compensated tunable filter calibration device in a Bragg-grating interrogation system. The invention comprises two systems: 1) a dual substrate Bragg grating calibration system, the temperature of an array of gratings is estimated using an array of gratings bonded to a common host substrate and a single grating bonded to a material with a different coefficient of thermal expansion; 2) a hydrogen cyanide wavelength reference absorption cell that absorbs light at discrete wavelengths corresponding to the molecular vibration mode frequencies of the gas. A first photodetector sees the transmission spectrum and a second sees the reflections from Bragg gratings in a sensing array. In this system there is no temperature compensation step as the absorption lines are not sensitive to temperature.

Passive, temperature compensated techniques for tunable filter calibration in bragg-grating interrogation systems

A new optical sensing device containing fiber Bragg gratings, a scanning bandpass filter, an interferometer and multiple photodetectors is disclosed. The present invention also describes a new system and method for fibre Bragg grating (FBG) sensor interrogation and multiplexing. The new system combines a scanning Fabry-Perot (SFP) bandpass filter used to wavelength-multiplex multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fibre interferometer made with a 3&times;3 coupler to detect strain-induced wavelength shifts. A passive technique for interferometer drift compensation using non-sensing FBGs is included in the system. A complete prototype system interrogates four gratings in a single fiber at a Nyquist sampling rate up to 10 kHz, with a noise floor measured near 4 n&egr; Hz above 0.1 Hz. The inclusion of the interferometer drift compensation technique is shown to make quasi-static measurements feasible.

Optical sensing device containing fiber Bragg gratings

The invention includes a method and apparatus for monitoring wavelength of an optical channel. A tunable optical bandpass filter is used to correlate a signal from an optical transmission line with a signal from a reference light source. The signal from the reference light source passes through a reference gas cell. The absorption lines of the reference gas provide a known calibration standard against which measured values may be compared. The invention finds applications in optical transmission systems, including wavelength division multiplexed and dense wavelength division multiplexed (WDM and DWDM) optical communication systems.

Optical channel monitor with continuous gas cell calibration

A passive, temperature compensated tunable filter calibration device for a Bragg grating interrogation system. In a first system, a dual-substrate Bragg grating calibration system, the temperature of an array of gratings is estimated using an array of gratings bonded to a common host substrate and a single grating bonded to a material with a different coefficient of thermal expansion. Changes in a common temperature of the substrates is measured by monitoring the difference between shifts of grating wavelength. As a filter voltage is scanned from its lowest to its highest voltage, the voltages are recorded. The second lowest wavelength corresponds to the grating attached to the differing substrate. The voltages are used to calculate a voltage-to-wavelength function for the scanning range of the filter. To compensate for variations in a calibration curve and temperature variations of the calibration array, the temperature is estimated and function re-calculated at every pass of the scanning filter. In a second system, a hydrogen-cyanide wavelength reference absorption cell that absorbs light at discrete wavelengths corresponding to the molecular vibrational mode frequencies of the gas. With a broadband optical light input to the cell, the output displays the spectrum of the input with several narrow dips in the spectra corresponding to the absorption lines of the cell. A first photodetector sees the transmission spectrum and a second sees the reflections from Bragg gratings in a sensing array. The filter drive voltages that coincide with the dips of the transmission spectrum are used to calibrate the voltage-to-wavelength function of the scanning filter. In this system there is no temperature compensation step as the absorption lines are not sensitive to temperature.

A system for synchronizing chaotic transmitters and receivers that is less sensitive to channel effects than other known chaotic communication methods. The system employs duplicate transmitter and receiving modules and in addition to the chaotic output a synchronizing signal which occupies a reduced bandwidth. The small bandwidth affords the system a greater resistance to the affects of frequency dependent channel distortion and noise. The broad band chaotic signal is transmitted and appears to be noise to an unauthorized listener. The receiving unit employs band pass filtering, and when the signal is received the receiver filters the chaotic signal through band pass filters which eliminate channel noise and make gain control easier to implement.

Growing community of inventors

Alexandria, VA, United States of America

Gregg A Johnson