Abstract: A process of determining an imminent-collision between a vehicle and an object, said vehicle having a sensing system for obtaining one or more images representing at least one observed object within a field of detection, said process comprising: (a) obtaining one or more images representing an observed object within said field of detection; and (b) determining that a collision between said vehicle and said observed object is imminent when the ratio of the probability that said observed object is actually within a collision zone to the probability that said observed object is actually within a safe zone is greater than a certain value.

Abstract: A bidirectional amplification system and method are disclosed. A single optical line amplifier and isolation loss filters are used to amplify signals in both the east and west directions with sufficient gain along a fiber.

Abstract: A gas species monitoring system includes a laser, a fiber amplifier configured to receive an input signal from the laser and generate an amplified signal, and a variable optical attenuation system configured to receive at least a portion of the amplified signal and generate an attenuated signal for delivery to a measurement point, where the measurement point includes a gaseous fluid. The system further includes a detector configured to receive and process a signal from the measurement point so as to obtain a measured signal that correlates with the presence of a gas species within the gaseous fluid at the measurement point, and a processor in communication with at least the variable optical attenuation system and the detector. The processor controls the variable optical attenuation system based upon the measured signal.

Abstract: An optical amplifier system and controller and a method for automatically controlling the usable signal power of an optical amplifier are provided. The method differentiates between the total optical power that includes the amplified spontaneous emission (ASE), and the useful amplified optical signal power at the output of the amplifier. The optical amplifier system comprises an optical amplifier, a first and a second photodetector operable to measure the power of the input and output signals of the optical amplifier and an amplification controller with a control input. The amplification controller is operable to compensate for the ASE power when operating in automatic signal power control mode.

Abstract: A computer-implemented method of accounting for angle-dependent wavelet stretch in seismic data based on a novel relationship between wavelet stretch and the cosine of a reflection angle of an acoustic ray. Conventional seismic data having at least one wavelet, such as data generated from a reflection seismic survey, is accessed. The data is processed such that at least one wavelet is subject to angle-dependent wavelet stretch. A reflection angle for at least one wavelet is also determined. An operator is utilized to calculate a wavelet stretch factor for at least one wavelet based on the cosine of the corresponding reflection angle of the wavelet. The wavelet stretch factor is applied to the seismic data to account for angle-dependent wavelet stretch.

Abstract: The present invention provides a solar-pumped active device which utilizes a holographic antenna grating on a solar energy silicon substrate to select specific diffracted wavelength and couple pump wavelength in an approximately vertical way and converge the pump wavelength to excite an optical gain medium so that an optical amplifier or a laser can be obtained. The present invention requires no big size and is flexible over the surface shape and is suitable for free space optical communications on the ground and satellite optical communications. It means that the holographic antenna grating can be applied on the top floor of a building or on the glass surface of an outer wall. If it is applied to a satellite, the present invention can be deposited on a solar energy cell substrate to form a high optical amplification so that not only the electricity required in satellite optical communications can be reduced, but also a high-speed and large capacity of data can be transferred between satellites.

Abstract: Optical amplifying method and apparatus are proposed. Constant gain amplifiers operate such that the output power of the amplifier generally tracks the input power. However, optical systems are not perfect and the input to the optical amplifier stage includes not only the desired signal, but also includes accumulated effects of the imperfections. The imperfections include losses of the fiber sections, variations in laser powers, and drifts. Thus, simple amplification not only amplifies the desired signal, but also amplifies accumulated imperfections. Such imperfections occur over time and are generally small in magnitude. By operating the amplifier such that amplification of small variations is suppressed while allowing for tracking of large input variations, amplifying the accumulated imperfections is minimized.

Abstract: Methods and systems for efficiently acquiring towed streamer marine seismic data are described. One method and system comprises positioning a plurality of source-only tow vessels and one or more source-streamer tow vessels to acquire a wide- and/or full-azimuth seismic survey without need for the spread to repeat a path once traversed. Another method and system allows surveying a sub-sea geologic feature using a marine seismic spread, the spread smartly negotiating at least one turn during the surveying, and shooting and recording during the turn. This abstract is provided to comply with the rules requiring an abstract, allowing a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: An amount of ASE generated changes due to a temperature and respective powers of signals input to and output from an optical amplifying unit, causing a fluctuation of a gain of the optical amplifying unit. A photodiode on an input side and a photodiode on an output side detect the input and output powers, and temperature detecting unit detects an operating temperature of the optical amplifier. A control unit corrects the amount of ASE generated, based on at least one of the detected input and output signal powers and on the detected temperature according to AGC control, which controls driving of an excitation LD for the optical amplifier to keep a gain of the optical amplifier constant.

Abstract: Methods and systems for measuring a brake stroke of an air brake assembly utilize a sensor, such as an accelerometer, mountable on a movable component, such as a brake cam shaft, of the air brake assembly that is external of the brake chamber of the air brake assembly for detecting an acceleration of the movable component during a braking event. The sensor generates an output signal that depends on a magnitude of the detected acceleration, which is sent to a microcontroller coupled to the sensor. The microcontroller translates the sensor output signal to a value corresponding to a displacement of the movable component of the brake assembly during the braking event and calculates a brake stroke distance based on said value.

Abstract: The amplifying optical fiber comprises a single-mode core and a multimode core surrounding the single-mode core, the multimode core containing a doped layer referred to as a “doped ring” and having a certain concentration of active rare earth ions to perform amplification by active rare earth ions on at least one optical signal for injection into the amplifying fiber. The fiber is dimensioned so that the product of its length multiplied by its Raman efficiency is greater than or equal to 0.5 W?1. In addition, the fiber presents absorption defined by an absorption coefficient expressed in dB/m, which absorption presents, at a certain wavelength, a maximum value referred to as the “absorption maximum”, the fiber presents accumulated absorption, corresponding to the product of its length multiplied by the absorption maximum, that is greater than or equal to 100 dB. The invention also provides an amplifier including such a fiber, a single-mode pump, and a multimode pump.

Abstract: A Raman amplifier providing a wideband gain for use in a wavelength division multiplexing (WDM) optical communication system. In one embodiment, a first optical amplifier Raman amplifies a wavelength division multiplexed signal light in both a first wavelength band and a second wavelength band in accordance with a plurality of excitation (pumping) lights provided to the first optical amplifier, the first and second wavelength bands being different from each other. A divider divides the amplified signal light into first and second lights in the first and second wavelength bands, respectively. A second optical amplifier amplifies the first light and has a gain band in the first wavelength band. The third optical amplifier amplifies the second light and has a gain in the second wavelength band. In various embodiments, a gain equalizer and/or an optical isolator is used in combination with the first optical amplifier providing the Raman amplification.

Abstract: According to a preferred aspect of the instant invention, there is provided a system and method for acquiring seismic data in a marine environment, wherein at least two source vessels are used in conjunction with a recording vessel which tows a plurality of hydrophone cables. Preferably, the source vessels will be positioned along side of the towed streamer configuration and most preferably one source vessel will be located near the recording vessel and the other at the end of the streamer configuration, preferably along the same side of the streamer configuration as the lead source vessel.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: Methods and systems for estimating one or more orientation parameters of a seismic apparatus are described. One method comprises initiating an acoustic signal from an acoustic transmitter in a marine seismic spread comprising a streamer, the streamer having at least two nodes separated by a fixed distance; measuring a first and a second difference in acoustic arrival times at the nodes for the acoustic signal; and using change in the second difference from the first difference to estimate orientation of the streamer. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: Provided is a hybrid optical amplifier using a gain-clamped semiconductor optical amplifier enabling Raman amplification. The hybrid optical amplifier comprises a spool of optical fiber used as transmission line in the optical communication, a GCSOA amplifying optical signal input via the optical fiber and generating a self-oscillation laser beam for gain-clamping through the gain medium, and a backward pumping Raman optical amplifier inducing Raman amplification by emitting the self-oscillation laser beam generated by the GCSOA into the optical fiber. Therefore, the Raman amplification can be obtained with a relatively simple structure using the GCSOA.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: To survey a subterranean structure, measured seismic data is processed using an algorithm for deriving a single-mode absorption parameter. A first absorption parameter for a mode-converted seismic wave is computed based on an output of the algorithm. The first absorption parameter represents an absorption effect of the mode-converted seismic wave by the subterranean structure, where the mode-converted seismic wave is reflected from the subterranean structure in response to a source seismic wave of a different mode than the mode-converted seismic wave.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: Reducing polarization dependence of a dispersion variation monitor includes receiving an optical signal. The optical signal is split into a first polarized signal having first photons and a second polarized signal having second photons. The first photons are received at a first material of a first detector, where the first material is operable to produce a reaction in response to the arrival of a predetermined number of photons. The second photons are received at a second material of a second detector, where the second material is substantially similar to the first material. A first current produced by the first material in response to receiving the first photons and a second current produced by the second material in response to receiving the second photons are monitored. Whether there is wavelength dispersion variation among the plurality of components is established in accordance with the first current and the second current.