The Experts below are selected from a list of 66294 Experts worldwide ranked by ideXlab platform
Liang Xie - One of the best experts on this subject based on the ideXlab platform.
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Tunable Carrier Generation and Broadband Data Upconversion for RoF Systems Based on Stimulated Brillouin Scattering
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Ninghua Zhu, Lixian Wang, Liang XieAbstract:We present a frequency-tunable RF carrier generation and Broadband Data upconversion technique for radio-over-fiber (RoF) systems. A dual-parallel Mach-Zehnder modulator is used to realize single-mode modulation (SMM). On the other hand, frequency-tunable RF carrier generation with single-sideband (SSB) modulation is performed using stimulated Brillouin scattering (SBS) with three types of configuration. The optical carrier-to-sideband ratio of the SMM-SSB modulated signal can be adjusted to achieve the best received sensitivity performance of the RoF system by simply modifying the pump power in the SBS process. Finally, the transmission performance of the RoF downlink system is examined. The power penalty is less than 1 dB at the bit-error rate of 10-9 after 25-km single-mode fiber transmission.
Ninghua Zhu - One of the best experts on this subject based on the ideXlab platform.
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Harmonic RF carrier generation and Broadband Data upconversion using stimulated Brillouin scattering
Optics Communications, 2011Co-Authors: Ninghua Zhu, Lixian WangAbstract:Abstract We propose and experimentally demonstrate a harmonic radio frequency (RF) carrier generation and Broadband Data upconversion technique with single mode and single sideband (− SSB) modulation for radio-over-fiber (RoF) systems using stimulated Brillouin scattering (SBS). The optical carrier-to-sideband ratio (CSR) of the single mode and SSB modulated signal can be easily adjusted to achieve the best received sensitivity performance of the RoF system. By using this method, we successfully demonstrate generation of third-harmonic RF carrier at 32.625 GHz with f LO of 10.875 GHz and upconversion of 1.25-Gb/s Data to the RF carrier band. In addition, the Data bandwidth is independent of the Brillouin gain profile. Finally, the transmission performance of the RoF downlink system is examined.
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Tunable Carrier Generation and Broadband Data Upconversion for RoF Systems Based on Stimulated Brillouin Scattering
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Ninghua Zhu, Lixian Wang, Liang XieAbstract:We present a frequency-tunable RF carrier generation and Broadband Data upconversion technique for radio-over-fiber (RoF) systems. A dual-parallel Mach-Zehnder modulator is used to realize single-mode modulation (SMM). On the other hand, frequency-tunable RF carrier generation with single-sideband (SSB) modulation is performed using stimulated Brillouin scattering (SBS) with three types of configuration. The optical carrier-to-sideband ratio of the SMM-SSB modulated signal can be adjusted to achieve the best received sensitivity performance of the RoF system by simply modifying the pump power in the SBS process. Finally, the transmission performance of the RoF downlink system is examined. The power penalty is less than 1 dB at the bit-error rate of 10-9 after 25-km single-mode fiber transmission.
Robert Soubaras - One of the best experts on this subject based on the ideXlab platform.
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Time Variant Amplitude and Phase Dispersion Correction for Broadband Data
SEG Technical Program Expanded Abstracts 2015, 2015Co-Authors: Feng Yang, Ronan Sablon, Robert SoubarasAbstract:Contrary to conventional seismic that focuses on a narrow band in middle frequencies, Broadband seismic aims at acquiring information within the whole bandwidth emitted by the source. A good knowledge of the source signature is thus of paramount importance in Broadband processing. However, the measurement of source signature is difficult and the modeling results are not satisfactory in the low frequencies. Another source of wavelet distortions is that seismic waves suffer from energy loss and phase dispersion due to intrinsic and apparent absorption which vary laterally and in depth. To address these challenges, a Datadriven time variant non-Gaussian wavelet estimation which is sensible to phase is developed. As demonstrated on a North Sea Broadband Dataset, the proposed technique is able to produce zero-phase Data on an enlarged bandwidth, both on low and high frequencies.
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Variable-depth streamer acquisition: Broadband Data for imaging and inversion
GEOPHYSICS, 2013Co-Authors: Robert Soubaras, Yves LafetAbstract:ABSTRACTConventional marine acquisition uses a streamer towed at a constant depth. The resulting receiver ghost notch gives the maximum recoverable frequency. To push this limit, the streamer must be towed at a quite shallow depth, but this compromises the low frequencies. Variable-depth streamer (VDS) acquisition is an acquisition technique aimed at achieving the best possible signal-to-noise ratio at low frequencies by towing the streamer very deeply, but by using a depth profile varying with offset in order not to limit the high-frequency bandwidth by notches as in conventional constant-depth streamer acquisition. The idea is to use notch diversity, each receiver having a different notch, so that the final result, combining different receivers, will have no notches. The key step to process VDS acquisitions is the receiver deghosting. We found that the optimal receiver deghosting, instead of being a preprocessing step, should be done postimaging, by using a dual-input, migration and mirror migration, an...
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Variable-Depth Streamer Acquisition: Broadband Data for Imaging, Inversion and Interpretation
2012Co-Authors: Robert Soubaras, Yves Lafet, Bruce VerwestAbstract:Variable-depth streamer acquisition is a solution for Broadband marine seismic where the depth profile of the streamer is optimized in order to create receiver ghost diversity, which in turn enables deconvolution of the residual ghost at the imaging stage, either pre-stack or post-stack.
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Variable-depth Streamer Acquisition - Broadband Data for Imaging and Inversion
73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, 2011Co-Authors: Robert Soubaras, Yves LafetAbstract:This paper starts by describing a new deghosting algorithm, based on computing a migration together with a mirror migration, and performing a joint deconvolution of these two images. It is true amplitude, being able to extract the true deghosted reflectivity, that is the reflectivity that would have been obtained should the water surface be not reflecting. The paper then describes how this new method allows to deghost acquisitions based on pre-stack notch diversity, such as the slant streamer technique. We revisit this acquisition technique in two ways: firstly, we optimize the depth profile of the streamer to ensure diversity for all reflectors depths, leading to variable-depth streamer rather than slant streamer. Secondly, recognizing that the stack performs an imperfect deghosting, leaving a residual ghost, we perform the residual deghosting with our new deghosting technique. This variable-depth streamer acquisition and processing has been tested on several locations. Here, we show results from a West Africa acquisition, where a 2.5-150 Hz bandwidth was achieved. This broad bandwidth translates into improved results for the acoustic impedance inversion.
Lixian Wang - One of the best experts on this subject based on the ideXlab platform.
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Harmonic RF carrier generation and Broadband Data upconversion using stimulated Brillouin scattering
Optics Communications, 2011Co-Authors: Ninghua Zhu, Lixian WangAbstract:Abstract We propose and experimentally demonstrate a harmonic radio frequency (RF) carrier generation and Broadband Data upconversion technique with single mode and single sideband (− SSB) modulation for radio-over-fiber (RoF) systems using stimulated Brillouin scattering (SBS). The optical carrier-to-sideband ratio (CSR) of the single mode and SSB modulated signal can be easily adjusted to achieve the best received sensitivity performance of the RoF system. By using this method, we successfully demonstrate generation of third-harmonic RF carrier at 32.625 GHz with f LO of 10.875 GHz and upconversion of 1.25-Gb/s Data to the RF carrier band. In addition, the Data bandwidth is independent of the Brillouin gain profile. Finally, the transmission performance of the RoF downlink system is examined.
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Tunable Carrier Generation and Broadband Data Upconversion for RoF Systems Based on Stimulated Brillouin Scattering
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Ninghua Zhu, Lixian Wang, Liang XieAbstract:We present a frequency-tunable RF carrier generation and Broadband Data upconversion technique for radio-over-fiber (RoF) systems. A dual-parallel Mach-Zehnder modulator is used to realize single-mode modulation (SMM). On the other hand, frequency-tunable RF carrier generation with single-sideband (SSB) modulation is performed using stimulated Brillouin scattering (SBS) with three types of configuration. The optical carrier-to-sideband ratio of the SMM-SSB modulated signal can be adjusted to achieve the best received sensitivity performance of the RoF system by simply modifying the pump power in the SBS process. Finally, the transmission performance of the RoF downlink system is examined. The power penalty is less than 1 dB at the bit-error rate of 10-9 after 25-km single-mode fiber transmission.
Yves Lafet - One of the best experts on this subject based on the ideXlab platform.
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Variable-depth streamer acquisition: Broadband Data for imaging and inversion
GEOPHYSICS, 2013Co-Authors: Robert Soubaras, Yves LafetAbstract:ABSTRACTConventional marine acquisition uses a streamer towed at a constant depth. The resulting receiver ghost notch gives the maximum recoverable frequency. To push this limit, the streamer must be towed at a quite shallow depth, but this compromises the low frequencies. Variable-depth streamer (VDS) acquisition is an acquisition technique aimed at achieving the best possible signal-to-noise ratio at low frequencies by towing the streamer very deeply, but by using a depth profile varying with offset in order not to limit the high-frequency bandwidth by notches as in conventional constant-depth streamer acquisition. The idea is to use notch diversity, each receiver having a different notch, so that the final result, combining different receivers, will have no notches. The key step to process VDS acquisitions is the receiver deghosting. We found that the optimal receiver deghosting, instead of being a preprocessing step, should be done postimaging, by using a dual-input, migration and mirror migration, an...
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Variable-Depth Streamer Acquisition: Broadband Data for Imaging, Inversion and Interpretation
2012Co-Authors: Robert Soubaras, Yves Lafet, Bruce VerwestAbstract:Variable-depth streamer acquisition is a solution for Broadband marine seismic where the depth profile of the streamer is optimized in order to create receiver ghost diversity, which in turn enables deconvolution of the residual ghost at the imaging stage, either pre-stack or post-stack.
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Variable-depth Streamer Acquisition - Broadband Data for Imaging and Inversion
73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, 2011Co-Authors: Robert Soubaras, Yves LafetAbstract:This paper starts by describing a new deghosting algorithm, based on computing a migration together with a mirror migration, and performing a joint deconvolution of these two images. It is true amplitude, being able to extract the true deghosted reflectivity, that is the reflectivity that would have been obtained should the water surface be not reflecting. The paper then describes how this new method allows to deghost acquisitions based on pre-stack notch diversity, such as the slant streamer technique. We revisit this acquisition technique in two ways: firstly, we optimize the depth profile of the streamer to ensure diversity for all reflectors depths, leading to variable-depth streamer rather than slant streamer. Secondly, recognizing that the stack performs an imperfect deghosting, leaving a residual ghost, we perform the residual deghosting with our new deghosting technique. This variable-depth streamer acquisition and processing has been tested on several locations. Here, we show results from a West Africa acquisition, where a 2.5-150 Hz bandwidth was achieved. This broad bandwidth translates into improved results for the acoustic impedance inversion.
