Abstract: An optical amplifying device disposed on a transmission path of a WDM signal includes an optical amplifier amplifying the WDM signal, a detecting unit detecting a change in a transmission wavelength count contained in the WDM signal and/or a change in light receiving level of the optical amplifier, a measuring unit measuring an optical signal to noise (SN) ratio of the WDM signal outputted from the optical amplifier, an update unit updating a reference value for evaluating the measurement value of the optical SN ratio obtained by the measuring unit when the detecting unit detects the change, a judging unit judging whether or not the measurement value deviates from an allowable range based on a reference value, and an output unit outputting an error of the optical amplifier if the measurement value deviates from the allowable range.

Abstract: An optical wavelength division multiplex transmission system (1) for transmitting optical signals (S) on a plurality of wavelength channels has a transmitting terminal (2) and a receiving terminal (3) interconnected by a transmission line (5) with at least one, preferably a plurality of optical amplifiers (4). Each of the optical amplifiers (4) comprises a Raman amplifier (6) with at least one pump light source (8.1-8.3) for pumping the transmission line (5) upstream the optical amplifier (4). It is proposed that each optical amplifier (4) comprises a single tap coupler (11) arranged downstream of the Raman amplifier (6). Optical receiving and transmitting means (14, 15) may be connected to the transmission line (5) via the tap coupler (11) for communication of data (TX, Di) between at least the transmitting terminal (2) and the optical amplifiers (4) on an optical supervisory channel (OSC) with a given wavelength.

Abstract: A vertical cavity semiconductor optical photoamplifer (VCSOA) is used as a modulating retro-reflector (MRR) as a pixel in an array. The boundary of the cavity in the VCSOA forms a mirror for reflecting an incident light as an amplified output.

Abstract: The present invention provides an optical switch including a loss element having a signal loss, and a rare earth doped gain element optically connected in series with the loss element. The rare earth doped gain element is operable to produce a signal gain. The signal gain and the signal loss are about equal. The present invention also provides a method of optical switching including optically connecting a loss element in series with a rare earth doped gain element and passing an optical signal through the loss element and the gain element. The loss element attenuates the optical signal by a first amount. The method further includes selectively applying an optical pump to the gain element to perform the switching, the gain element amplifying the optical signal by the first amount in response to the optical pump.

Abstract: A method for reconstructing seismic data signals of poor quality to improve the signal-to-noise ratio of the data for display and analysis in connection with the selection of drilling sites for recovery of hydrocarbons. The method includes providing a signal model by applying a Karhunen-Loeve transform to selected input seismic data collected for the target zone, to form a co-variance matrix from the dot products of all pairs of input data. Eigenvalues and eigenvectors for the matrix are computed, and the most significant eigenvectors are inversely transformed to provide a coherent estimate of the signal. The input data is combined with the model data based on the determination that the model data lacks continuity, wherein the good quality signal-to-noise ratio data experiences little change and discontinuous data is enhanced by a contribution of the signal estimate data. The reconstructed seismic data of the target zone can be displayed for analysis.

Abstract: Method of synthesis of photonic band gap (PBG) materials. The synthesis and characterization of high quality, very large scale, face centered cubic photonic band gap (PBG) materials consisting of pure silicon, exhibiting a complete three dimensional PBG centered on a wavelength of 1.5 ?m. This is obtained by chemical vapor deposition and anchoring of disilane into a self-assembling silica opal template, wetting of a thick silicon layer on the interior surfaces of the template, and subsequent removal of the template. This achievement realizes a long standing goal in photonic materials and opens a new door for complete control of radiative emission from atoms and molecules, light localization and the integration of micron scale photonic devices into a three-dimensional all-optical micro-chip.

Abstract: An optical amplifying apparatus connected mutually through an optical transmission line includes an optical detecting unit for detecting an input level of an amplified spontaneous emission (ASE) light, an optical amplifying unit for amplifying a signal light, and an optical attenuating unit for adjusting an attenuation level for the signal light, which being installed on an input side of the optical amplifying unit. The optical attenuating unit adjusts the attenuation level for the signal light, based on a difference between an output level of the ASE light outputted from the preceding optical amplifying apparatus and the input level of the ASE light inputted thereto.

Abstract: This invention provides an optical transmission system which allows to perform high-quality transmission of each of a plurality of signal channels multiplexed. In the optical transmission system, signal light in which a plurality of signal channels with an optical frequency spacing of 400 GHz or more but 12.5 THz or less is transmitted from an optical transmitter to a Raman amplifier through an optical fiber transmission line. In the Raman amplifier, pumping light from a pumping light source unit is supplied to an optical fiber through an optical coupler. The multiplexed signal light inputted to the Raman amplifier arrives at the optical fiber through an optical isolator and optical coupler, and Raman-amplified by the optical fiber. The Raman-amplified multiplexed signal light is outputted from the Raman amplifier through an optical coupler and optical isolator.

Abstract: An optical amplifier is described that comprises at least two sections of amplifying optical fibre and pumping means for optically pumping the amplifying optical fibre. Optical fibre support means, for example a channel or channels in a substrate, are also provided to hold the two or more sections of amplifying optical fibre substantially straight during use. The optical fibre support means also includes a means for coupling light between the at least two sections of amplifying optical fibre. The at least one amplifying optical fibre may comprise an Erbium doped core to provide an erbium doped fibre amplifier (EDFA).

Abstract: This invention provides a method for commissioning an optical network using internal Automatic Spontaneous Emission (ASE) light inherently present in the optical network as a light source (the ASE light source) for measuring losses inside and between nodes in the network. A modular segmented approach is adopted and the network is commissioned segment by segment. The method uses techniques for the correction of the Optical Signal to Noise Ratio induced error as well as the Spectral Filtering Error during the loss computation required for adjusting the gains of the amplifiers at each network node to an appropriate value. Since the method does not require an external laser source that needs to be moved manually from node to node, it greatly reduces the commissioning time. Since it uses only the existing components of the network nodes it also leads to a significant saving in cost.

Abstract: In conventional optical isolators, an optical signal is dispersed by polarization or the characteristics are varied by heat generation in a garnet crystal. According to the invention, the crystal optical axis (3c) of rutile crystal (3) is oriented so that the separation directions of the ordinary ray (O) and the extraordinary ray (E) are perpendicular to the plane including the optical axes of optical fibers (10, 11). Furthermore, the focusing central optical axis (6c) of a focusing rod lens (6) is arranged parallel with optical axes of the optical fibers (10, 11) and at a substantially equal distance from the four rays, i.e. the ordinary ray (O) and the extraordinary ray (E) propagating along the optical axis of the optical fiber (10) and the ordinary ray (O) and the extraordinary ray (E) propagating along the optical axis of the optical fiber (11). An air gap (7) of about 200 [?m] is provided, as a heat insulating means, between the focusing rod lens (6) and a magnetized garnet crystal (8).

Abstract: Provided are a broadband light source suitable for a pump light module for Raman amplification and a Raman amplifier which uses such light source. The broadband light source comprises a light source system for emitting light having two or more different output peak wavelengths and a nonlinear medium having an input port and an output port, and the nonlinear medium affords nonlinear effect on light emitted from the light source system and input from the input port, and outputs the resultant light as pump light from the output port. The Raman amplifier, which comprises an optical fiber for Raman amplification, a multiplexing module, and the broadband light source of the present invention, amplifies signal light propagating through the optical fiber for Raman amplification.

Abstract: A system and methods for enhancing an image of post-stack seismic data, with pre-stack seismic data features, and displaying the enhanced image with the image of the post-stack seismic data are disclosed.

Abstract: Monitoring of the input power is performed on-chip and is used to monitor and maintain performance, detect failure and trigger network protection strategies. An optical power-monitoring technique uses a photodetector monolithically integrated with the semiconductor optical amplifier—Mach-Zehnder interferometer circuit to monitor the P2R device and keep the output stable while the input power varies.

Abstract: A method of characterizing shear wave anisotropy in a formation includes obtaining crossed-dipole waveforms from a borehole penetrating the formation over a range of depths and frequencies, determining far-field slowness in a fast-shear and slow-shear direction using a low-frequency portion of the crossed-dipole waveforms, and determining near-wellbore slowness in the fast-shear and slow-shear directions using a high-frequency portion of the crossed-dipole waveforms. The method also includes marking a selected depth of the formation as having intrinsic anisotropy if at the selected depth the far-field slowness in the fast-shear direction is less than the far-field slowness in the slow-shear direction and the near-wellbore slowness in the fast-shear direction is less than the near-wellbore slowness in the slow-shear direction.

Abstract: The present invention relates to a Raman amplifier where flexibility in device design considering both of Raman amplification and dispersion compensation is high. In the Raman amplifier, the Raman amplification optical fiber included in the optical amplification section and the dispersion compensating optical fiber included in the dispersion compensation section are arranged while being optically connected to each other. Since the optical amplification section and the dispersion compensation section are provided as independent optical devices, one device can be designed without being restricted to the design conditions of the other device.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of and is disposed inside the jacket. At least one seismic sensor is disposed in a sensor spacer mounted to the at least one strength member. The streamer includes means for retaining the at least one sensor spacer to the at least one strength member. The means for retaining provides substantial acoustic isolation between the at least one spacer and the at least one strength member.

Abstract: A 2-?m fiber Amplified Spontaneous Emission (ASE) source provides a wide emission bandwidth and improved spectral stability/purity for a given output power. The fiber ASE source is formed from a heavy metal oxide multicomponent glass selected from germanate, tellurite and bismuth oxides and doped with high concentrations, 0.5-15 wt. %, thulium oxides (Tm2O3) or 0.1-5 wt% holmium oxides (Ho2O3) or mixtures thereof. The high concentration of thulium dopants provide highly efficient pump absorption and high quantum efficiency. Co-doping of Tm and Ho can broaden the ASE spectrum.

Abstract: An optical integrated device includes a plurality of input optical waveguides connected respectively to a plurality of input ports provided on one end face of the optical integrated device, a single output optical waveguide connected to an output port, an optical coupler for optically coupling signal lights propagated along the plural input optical waveguides to the single output optical waveguide, and a semiconductor optical amplifier gate array formed from a plurality of semiconductor optical amplifiers provided on the input optical waveguides, respectively, and each having an electrode on the surface thereof. The optical integrated device further includes a plurality of signal lines formed on the surface of the optical integrated device in such a manner as to extend from the electrodes to an end face of the optical integrated device on which none of the input ports and the output port is provided.

Abstract: An optical component for gain-flattening multiplexed passband signals amplified with optical pump power, comprises a launch port optical waveguide operative to communicate multiplexed passband signals in a passband wavelength range and optical pump power in a different wavelength range; a thin film demux filter oriented to receive combined multiplexed passband signals and optical pump power from the launch port optical waveguide, and operative to pass the multiplexed passband signals and to reflect the optical pump power; a bypass port optical waveguide operative and oriented to receive and carry optical pump power reflected by the demux filter; a gain-flattening filter positioned to receive from the thin film demux filter and operative to pass the multiplexed passband signals with a desired attenuation profile for gain-flattening; and an output port optical waveguide oriented to receive and operative to carry at least multiplexed passband signals passed by the gain-flattening filter.