Abstract: A line amplification system connected on the fiber between two flexibility sites of a wavelength switched network is built with a number of modules that can be arranged in a line amplifier, preamplifier and postamplifier configurations. The line and preamplifiers include a Raman module and a two-stage EDFA module provided with mid-stage access. A dynamic gain equalizer is connected in the mid-stage in the line amplification configurations. As well, dispersion compensating module may be connected in the mid-stage whenever/if needed. A line monitoring and control system operates the line amplification system so that all channels traveling along a link have substantially the same power, in the context of channels being added and removed to/from the line arbitrarily.

Abstract: A method and apparatus for determining acoustic mud velocity and bore hole caliper in a downhole environment. A highly accurate acoustic signal is adjusted for mud velocity as continuously measured. The borehole standoff is utilized to compensated data collected downhole in determining a parameter of interest in the wellbore or an adjacent formation.

Abstract: A method for determining properties of an earth formation surrounding an earth borehole that involves: providing a logging device moveable through the borehole; transmitting sonic energy into the formation; receiving sonic energy that has traveled through the formation; producing signals representative of the received sonic energy; determining whether the formation is anisotropic; determining whether the formation is inhomogeneous; and outputting a characterization of the formation as one of the following types: isotropic/homogeneous, anisotropic/homogeneous, isotropic/inhomogeneous, and anisotropic/inhomogeneous.

Abstract: An apparatus and method are described for exploiting almost the full almost 25 THz of bandwidth available in the low-loss window in optical fibers (from 1430 nm to 1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths &lgr;r should lie in close proximity to the zero-dispersion wavelength &lgr;0 of the amplifying fiber.

Abstract: An apparatus and method for suppressing multiples in the collection of marine seismic data comprises at least one source positioned in the body of water; at least one receiver positioned in the body of water below the air-water interface and near the sources; a bubble diffuser positioned in the body of water so that the bubbles emitted by the bubble diffuser are positioned between the receivers and the air-water interface, wherein the emitted bubbles provide high acoustic reflection and substantially suppress specular reflection of seismic waves; and a control for activating the bubble diffuser during the collection of seismic data by the sources and receivers.

Abstract: A method of delivering a seed-pulse to a regenerative amplifier includes generating an ultrashort optical pulse. The ultrashort optical pulse is delivered to a single-mode optical fiber configured to generate a continuum. A portion of the continuum generated by the optical fiber is selected by a pulse stretcher and converted into the seed pulse. The pulse stretcher can be tuned to provide seed pulses of selectively variable wavelength.

Abstract: The invention relates to a vibroseis analysis method in which frequency-sweep signals (10) are emitted into a subsurface, the signals reflected on the substrata of such a subsurface (10, 20) are logged and the logged signals are processed, a method in which the harmonics (20) of the fundamental signal (10) initially emitted are eliminated from the logged signals, by applying the steps consisting in: a) providing a time/frequency plot, showing the respective contributions of the fundamental (10) and of the harmonics (20) in the logged signal, b) providing a time/frequency plot also showing these contributions of the fundamental (10) and of the harmonics (20) in the logged signal, this plot having been stretched in the direction of the frequency axis such that the fundamental (10) of this plot is over the location of a harmonic (20) chosen from the plot; c) adapting the power amplitude of this stretched plot to make this amplitude correspond to that of the said chosen harmonic (20) of the plot; d) subtracti

Abstract: An amplified broadband optical signal is produced in a transmission system. An optical signal is divided into a first beam and a second beam. The first beam has a wavelength less than a predetermined wavelength. The second beam has a wavelength greater than the predetermined wavelength. The first beam is directed to a transmission link in the transmission system. The transmission system includes a distributed Raman amplifier. The distributed Raman amplifier operates in the wavelength range less than 1480 nm. The second beam is directed to a second amplifier. The first and second beams are combined. An amplified broadband optical signal is produced.

Abstract: The invention concerns elemental silicon emission devices. Devices according to the invention use elemental silicon nanoparticles as a material from which stimulated emissions are produced. Silicon nanoparticles efficiently produce emissions and act as a gain medium in response to excitation. The silicon nanoparticles of the invention, being dimensioned on an order of magnitude of one nanometer and having about 1 part per thousand or less larger than 1 nm, are an efficient emission source and forms the basis for many useful devices.

Abstract: A method and apparatus for measuring the properties, such as permeability, of the rock surrounding a metal cased borehole by generating a seismic or sonic shock downhole within the borehole which is propagated into the surrounding formation where it generates an electrokinetic signal which is detected by measuring the potential between at least two space apart electrodes in contact with the casing.

Abstract: An apparatus and method are described for exploiting almost the full almost 25TH% of bandwidth available in the low-loss window in optical fibers (from 1430 nm-1620 nm) using a parallel combination of optical amplifiers. The low-loss window at about 1530 nm-1620 nm can be amplified using erbium-doped fiber amplifiers (EDFAs). However, due to the inherent absorption of the erbium at shorter wavelengths, EDFAs cannot be used below about 1525 nm without a significant degradation in performance. For the low-loss window at approximately 1430-1530 nm, amplifiers based on nonlinear polarization in optical fibers can be used effectively. A broadband nonlinear polarization amplifier (NLPA) is disclosed which combines cascaded Raman amplification with parametric amplification or four-wave mixing. In particular, one of the intermediate cascade Raman order wavelengths &lgr;r should lie in close proximity to the zero-dispersion wavelength &lgr;0 of the amplifying fiber.

Abstract: Seismic wave reception device comprising a hydrophone and/or a geophone and method for coupling it (or them) with a solid medium such as the subsoil. The device comprises at least one hydrophone (2) immersed in a closed flexible-walled sheath (7) filled with liquid (8) that is closed at one end by a sealed plug (9) provided with a sealed duct for a cable (10) connecting the hydrophone to a signal acquisition means (E). The sheath is arranged in a cavity (6) and tightly coupled with medium (5) substantially over the total surface thereof, preferably by means of a hardenable material such as cement. A geophone can be placed in the same coupling material in the vicinity of sheath (7) containing hydrophone (2). Application: seismic prospecting or monitoring operations in an underground formation, notably in order to discriminate the seismic upgoing and downgoing waves.

Abstract: An optical amplifier includes at least a first wavelength multiplexing unit for multiplexing a signal light and a pumping light source, a first optical amplifying medium for amplifying the signal light by utilizing the pumping light and providing an output of amplified signal light, a first demultiplexing unit, a first dispersion compensation unit for receiving the amplified signal light from the first demultiplexing unit and modifying a waveform of the amplified signal light so as to compensate for waveform distortion of the signal light along a transmission path of the signal light and providing an output of a waveform modified signal light, a second wavelength multiplexing unit, a second optical amplifying medium, a second demultiplexing unit, and a second dispersion compensation unit. The optical amplifier also forms a part of an optical transmitter and an optical receiver.

Abstract: An optical amplifying apparatus of the present invention comprises a correction part for correcting a predetermined fixed value of an output optical level by a correction amount according to an optical power of amplified spontaneous emission (ASE). The correction amount is, for example, computed by predetermined formulas. According to the present invention, when a WDM optical signal is optically amplified, the output is fixedly amplified for each channel by the correction amount which is a value obtained with the ASE levels taken into consideration, so that a fluctuation in the level of the average optical power of the channels is suppressed even if an optical signal is dropped/added therefrom/thereto during repeated transmissions.

Abstract: There is proposed an optical amplifier apparatus particularly for use in networks distributing signals by optical fibers, comprising first and second parallel optical branches (1, 2), the first optical branch (1) including optical amplifier means (5, 6) for amplifying digital signals and the second optical branch including optical amplifier means (7) for amplifying analogue signals, the optical amplifier means (5, 6) of the first optical path (1) being adapted to amplify bidirectional digital signals and the optical amplifier means (7) of the second optical branch (2) being adapted to amplify unidirectional analogue signals.

Abstract: The specification describes rare earth doped fiber amplifier devices for operation in the extended L-band, i.e. at wavelengths from 1565 nm to above 1610 nm. High efficiency and flat gain spectra are obtained using a high silica based fiber codoped with Er, Al, Ge, and P and an NA of at least 0.15.

Abstract: An optical transmission system is provided comprising a thulium doped optical fiber, a light emitting pump device optically coupled to the thulium doped fiber, and a Raman amplifier fiber optically coupled to the thulium doped optical fiber. The light emitting pump device in combination with the thulium doped fiber generates a first amplification pump wavelength and the Raman amplifier receives the first amplification pump wavelength. The first pump wavelength amplifies an optical signal in the Raman amplifier, the Raman amplifier operating at a signal wavelength in the range of about 1530 nm to about 1625 nm.

Abstract: A semiconductor optical amplifier includes a plurality of active layers of bulk crystal with at least one intervening spacer for optical amplification, wherein each of the active layers accumulates a tensile strain therein.

Abstract: A method for tuning and improving the performance of an optical communication system comprising al link that includes optical amplifiers and, optionally, active and/or passive optical components such as, e.g., DWDM's, WADM's, and optical cross-connects, includes preferentially shaping and, in particular, flattening, with respect to the input power spectrum, the output power spectrum from the amplifier, component or of the link. A flattened output power spectrum is obtained by modifying the gain spectrum operating on the respective input power spectrum. Feedback for such gain modification is typically provided by optimizing the optical signal to noise ratio of each channel of the respective output power spectrum. A system link, an optical amplifier, and optical components having flattened output power spectra are also described.

Abstract: A method of amplifying, transmitting and receiving a signal light. The method includes multiplexing the signal light and a pumping light from a pumping light source so as to output the signal light and the pumping light, and amplifying the signal light by utilizing the pumping light and providing an output of amplified signal light. The amplified signal light and the pumping light are received and the amplified signal light and the pumping light are separately outputted. The outputted amplified signal light is received and a waveform of the amplified signal light is modified so as to compensate for waveform distortion of the signal light along a transmission path of the signal light and an output of a waveform modified signal light is provided. The waveform modified signal light which is received and the pumping light which is received is multiplexed so as to output the waveform modified signal light and the pumping light.