Abstract: Implementations of various techniques for processing seismic data acquired by three or more over/under streamers. In one implementation, the seismic data may be processed by grouping the seismic data into one or more sets of seismic data based on all possible pairs of the three or more over/under streamers, wherein each set of seismic data comprises seismic data that had been acquired by a pair of the three or more over/under streamers, applying a shift and subtract algorithm to the one or more sets of seismic data, and applying a dephase and sum algorithm to the one or more sets of seismic data.

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: A method includes conditioning a set of multicomponent seismic data and sensor orientation data, the multicomponent seismic data including pressure data and particle motion data, acquired in a towed array, marine seismic survey; digital group forming the conditioned pressure data, a vertical particle motion component of the conditioned particle motion data, and the conditioned sensor orientation data; and summing the digitally group formed pressure data and the digitally group formed vertical particle motion component.

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: On the upstream side of a quantum dot optical amplifier, a polarization beam splitter with one input and two outputs is provided. Two optical fibers connected to output sections of the polarization beam splitter are connected to input sections of the quantum dot optical amplifier in a state that both of the optical fibers have an electric field whose direction being adjusted to maximize its gain, and one optical fiber is twisted by 90° to the other optical fiber. On the downstream side of the quantum dot optical amplifier, a polarization beam splitter with two inputs and one output is provided. Between two optical fibers connected to the polarization beam splitter, one is twisted by 90° to the other. This twisting direction is reverse to the twisting direction of the two optical fibers connected to the input sections of the quantum dot optical amplifier.

Abstract: The field of the invention is that of devices for regenerating optical signals. It applies more particularly to systems for high-throughput long distance transmission by optical fibres of digital data. While propagating, optical signals necessarily experience attenuation and degradation of their signal/noise ratio. To compensate for these degradations, wholly-optical regeneration devices are generally used. The object of the invention is to ensure regeneration which in large part eliminates noise, without using auxiliary optical devices. This regeneration is ensured by a structure with saturable optical absorbent comprising an optical cavity of thickness L comprising at least one layer of active material of Henry factor ?H and of maximum absorption variation ?? such that the thickness L equals about 2?/(?H, ??).

Abstract: An optical transmitting apparatus includes a variable optical attenuating unit for attenuating signal light variably, an optical amplifying unit for amplifying the signal light, and a looped optical circuit for returning the signal light from the optical amplifying unit to the variable optical attenuating unit. The variable optical attenuating unit further attenuates the returned signal light variably.

Abstract: In a WDM transmission system employing a plurality of short wavelength bands having great attenuation due to optical fiber transmission, an optical repeater is constructed of a first multiplexing section and a second multiplexing section. The first multiplexing section is used for wavelength-multiplexing both the excitation light from a first Raman excitation light source, which distributively amplifies an S+ band included in light propagating through an optical fiber, and the light propagating through the optical fiber. The second multiplexing section is used for wavelength-multiplexing both the excitation light from a second Raman excitation light source, which distributively amplifies an S+ band included in light propagating through an optical fiber, and the light propagating through the optical fiber. The first and second multiplexing sections are provided between the optical fibers disposed between end offices. Thus an equal and satisfactory optical SN ratio even at any band are obtained.

Abstract: An optical amplifier includes a plurality of pump light sources, an intensity modulator that modulates intensity of a pump light to be output from any one of the pump light sources, at a predetermined frequency; a photoelectric converter that converts a part of the wavelength-division multiplexed signal light Raman-amplified by the pump light to electrical signals; a gain modulation signal detector that extracts a gain modulation signal having a component of the frequency from the electrical signals; and a controller that controls only the intensity of pump lights that are output from the pump light source, of which intensity is modulated at the frequency to control Raman amplification gain so that an amplitude of the gain modulation signal becomes a predetermined value. The intensities of pump lights output from individual pump light sources are sequentially controlled to obtain a predetermined value of the Raman amplification gain.

Abstract: Seismic sensor systems and sensor station topologies, as well as corresponding cable and sensor station components, manufacturing and deployment techniques are provided. For some embodiments, networks of optical ocean bottom seismic (OBS) stations are provided, in which sensor stations are efficiently deployed in a modular fashion as series of array cable modules deployed along a multi-fiber cable.

Abstract: A Raman amplifier for amplifying a wavelength division multiplexed (WDM) light including signal lights wavelength division multiplexed together. The amplifier includes an optical amplifying medium and a controller. The optical amplifying medium uses Raman amplification to amplify the WDM light in accordance with multiplexed pump lights of different wavelengths traveling through the optical amplifying medium. The WDM light is amplified in a wavelength band divided into a plurality of individual wavelength bands. The controller controls power of each pump light based on a wavelength characteristic of gain generated in the optical amplifying medium in the individual wavelength bands.

Abstract: A semiconductor optical amplifier (SOA) with efficient current injection is described. Injection current density is controlled to be higher in some areas and lower in others to provide, e.g., improved saturation power and/or noise figure. Controlled injection current can be accomplished by varying the resistivity of the current injection electrode. This, in turn, can be accomplished by patterning openings in the dielectric layer above the current injection metallization in a manner which varies the series resistance along the length of the device.

Abstract: A control apparatus comprises a light monitoring unit for dividing a signal wavelength band into at least a band in which output light power of an optical amplifier tends to decrease at an decrease in the number of signal wavelengths and a band including a gain deviation band, and for monitoring inputted light power for the individual divided bands, a calculation unit for obtaining the number of signal wavelengths in the individual divided bands based on a monitor result, and a target gain correction unit for correcting a target gain based on a result of the calculation. This suppresses a transient variation of signal light level due to SHB or SRS at a high speed with a simple configuration without deteriorating noise characteristic, thus enabling optical amplifiers to be further disposed in a multi-stage fashion, which can lengthen the transmission distance of a transmission system including an optical add/drop unit.

Abstract: A Raman amplification active optical fiber comprises a core containing silica oxide (SiO2), lithium oxide (Li2O), germanium oxide (GeO2), and barium oxide (BaO). The core contains 30 to 90 molar percent of SiO2 and less than 50 molar percent of the combination of LiO2, GeO2, and BaO. Application of the fiber to a multiwavelength Raman fiber laser.

Abstract: The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

Abstract: Optical transmission systems including a plurality of optical amplifiers configured to provide optical amplification of one or more information carrying optical signal wavelengths. At least two of the optical amplifiers are operated to provide net losses or net gains along corresponding spans, while the cumulative gain provided by the plurality of optical amplifiers substantially compensates for the cumulative loss of the spans.

Abstract: A multi-band hybrid amplifier is disclosed for use in optical fiber systems. The amplifier uses Raman laser pumps and semiconductor optical amplifiers in series to produce a relatively level gain across the frequency range of interest. Multiple Raman pumps are multiplexed before coupling into the fiber. The Raman amplified optical signal may be demultiplexed and separately amplified by the SOAs before re-multiplexing. Gain profiles of the Raman pumps and the SOAs are selected to compensate for gain tilt and to alleviate the power penalty due to cross-gain modulation in the SOAs. The disclosed hybrid amplifier is especially useful in coarse wavelength division multiplexing (CWDM) systems.

Abstract: Optical transmission systems including a plurality of optical amplifiers configured to provide optical amplification of one or more information carrying optical signal wavelengths. At least two of the optical amplifiers are operated to provide net losses or net gains along corresponding spans, while the cumulative gain provided by the plurality of optical amplifiers substantially compensates for the cumulative loss of the spans.

Abstract: A system and method for combining plural low power light beams into a coherent high power light beam. Optical amplifiers transmit a plurality of light beams propagating at a common wavelength through an array of optical fiber emitters. Each constituent beam is emitted from the array at a different propagation angle, collimated, and incident on a diffractive optical element operating as a beam combiner such that incident beams when properly phased and located are combined into a coherent beam at a desired diffraction order. A beam splitter or a periodic sampling grating on the diffractive optical element directs a low power sample beam to a spatial filter passing resonant mode output back to the optical amplifiers in a ring laser configuration thereby passively synchronizing phases of the constituent beams to maximize combination efficiency of the coherent beam.

Abstract: An optical brancher branches an input optical signal into two. An optical detector converts one optical signal branched by the optical brancher into an electrical signal. A first controller generates a control electrical signal having a waveform obtained by inverting the envelope of the electrical signal. Based on the control electrical signal, an optical signal generator produces a dummy optical signal having a waveform ?d and an amplitude ?/2. The other signal branched by the optical brancher is delayed by a delay unit for a predetermined time, and then multiplexed by an optical multiplexer with the dummy optical signal from the optical signal generator. An optical amplifier amplifies amultiplexed optical signal. An optical filter separates an optical signal of a wavelength ?1 from the amplified optical signal. Thus, optical signal amplification can be carried out without optical surges.