The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jose Azana - One of the best experts on this subject based on the ideXlab platform.
-
programmable fiber optics microwave photonic filter based on Temporal talbot effects
International Topical Meeting on Microwave Photonics, 2018Co-Authors: Reza Maram, Jose Azana, Daniel Onori, Lawrence R ChenAbstract:We introduce and experimentally demonstrate a reconfigurable microwave photonic filter based on Temporal Talbot effects. An optical pulse source is employed to sample the microwave signal through intensity modulation. The sampled signal is then propagated through the Talbot-based microwave photonic filter, involving Temporal Phase modulation and chromatic dispersion. The microwave photonic filter exhibits a periodic transfer function whose passband frequency and frequency periodicity (free spectral range) can be programmed electrically by adjusting the Phase-modulation profile, e.g., using an arbitrary waveform generator, without the need for manual adjustment of the optical components and with the potential for fast tuning of the filter’s response. The bandwidth of the filter passband can also be easily customized by adjusting the sampling pulse width using an optical bandpass filter.
-
linear optical pulse compression based on Temporal zone plates
Optics Express, 2013Co-Authors: Shuqin Lou, Jose AzanaAbstract:We propose and demonstrate time-domain equivalents of spatial zone plates, namely Temporal zone plates, as alternatives to conventional time lenses. Both Temporal intensity zone plates, based on intensity-only Temporal modulation, and Temporal Phase zone plates, based on Phase-only Temporal modulation, are introduced and studied. Temporal zone plates do not exhibit the limiting tradeoff between Temporal aperture and frequency bandwidth (Temporal resolution) of conventional linear time lenses. As a result, these zone plates can be ideally designed to offer a time-bandwidth product (TBP) as large as desired, practically limited by the achievable Temporal modulation bandwidth (limiting the Temporal resolution) and the amount of dispersion needed in the target processing systems (limiting the Temporal aperture). We numerically and experimentally demonstrate linear optical pulse compression by using Temporal zone plates based on linear electro-optic Temporal modulation followed by fiber-optics dispersion. In the pulse-compression experiment based on Temporal Phase zone plates, we achieve a resolution of ~25.5 ps over a Temporal aperture of ~5.77 ns, representing an experimental TBP larger than 226 using a Phase-modulation amplitude of only ~0.8π rad. We also numerically study the potential of these devices to achieve Temporal imaging of optical waveforms and present a comparative analysis on the performance of different Temporal intensity and Phase zone plates.
-
Temporal Phase zone plates for linear optical pulse compression
CLEO: 2013, 2013Co-Authors: Bo Li, Ming Li, Jose AzanaAbstract:We demonstrate linear optical pulse compression by using Temporal Phase zone plates based on electro-optic Phase modulation, achieving experimental time-bandwidth products (or equivalent time compression factors) > 150 using Phase-modulation amplitudes of only ττ radians.
-
discretely tunable comb spacing of a frequency comb by multilevel Phase modulation of a periodic pulse train
Optics Express, 2013Co-Authors: Antonio Malacarne, Jose AzanaAbstract:We experimentally demonstrate tunable comb spacing of an original 10-GHz periodic frequency comb by spectral Talbot effect over an unprecedented range of even and odd comb spacing division factors, from 2 to 9. The implementation has been achieved by periodic electro-optic (EO) Temporal Phase modulation of the original comb (conventional mode-locked optical pulse train) with multilevel modulation functions, produced by an arbitrary waveform generator (AWG). These comb spacing division processes have been observed through the use of a high-resolution (20-MHz) optical spectrum analyzer. Comb spacing tuning is achieved without essentially affecting the spectral bandwidth and total energy of the original comb signal. Our results also confirm that the spectral Talbot method does not require carrier-envelope Phase stabilization in the input frequency comb. Numerical studies on the impact of deviations in the applied Phase modulation functions confirm the robustness of the technique, in agreement with the experimental results.
-
discretely tunable free spectral range of a frequency comb by Temporal Phase modulation of a periodic pulse train
Conference on Lasers and Electro-Optics, 2012Co-Authors: Antonio Malacarne, Jose AzanaAbstract:We experimentally demonstrate FSR tuning of a 10-GHz periodic frequency comb through spectral Talbot effect over a range of division factors from 2 to 9. Robustness to deviations in the Phase modulation signal is analyzed.
Paul R Prucnal - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Phase mask encrypted optical steganography carried by amplified spontaneous emission noise
Optics Express, 2014Co-Authors: Ben Wu, Bhavin J Shastri, Matthew P Chang, Nicholas A Frost, Zhenxing Wang, Paul R PrucnalAbstract:A Temporal Phase mask encryption method is proposed and experimentally demonstrated to improve the security of the stealth channel in an optical steganography system. The stealth channel is protected in two levels. In the first level, the data is carried by amplified spontaneous emission (ASE) noise, which cannot be detected in either the time domain or spectral domain. In the second level, even if the eavesdropper suspects the existence of the stealth channel, each data bit is covered by a fast changing Phase mask. The Phase mask code is always combined with the wide band noise from ASE. Without knowing the right Phase mask code to recover the stealth data, the eavesdropper can only receive the noise like signal with randomized Phase.
-
Improving the privacy of optical steganography with Temporal Phase masks
Optics express, 2010Co-Authors: Zhenxing Wang, Mable P. Fok, John Chang, Paul R PrucnalAbstract:Temporal Phase modulation of spread stealth signals is proposed and demonstrated to improve optical steganography transmission privacy. After Phase modulation, the Temporally spread stealth signal has a more complex spectral-Phase-Temporal relationship, such that the original Temporal profile cannot be restored when only dispersion compensation is applied to the Temporally spread stealth signals. Therefore, it increases the difficulty for the eavesdropper to detect and intercept the stealth channel that is hidden under a public transmission, even with a correct dispersion compensation device. The experimental results demonstrate the feasibility of this approach and display insignificant degradation in transmission performance, compared to the conventional stealth transmission without Temporal Phase modulation. The proposed system can also work without a clock transmission for signal synchronization. Our analysis and simulation results show that it is difficult for the adversary to detect the existence of the stealth transmission, or find the correct Phase mask to recover the stealth signals.
Yunhao Liu - One of the best experts on this subject based on the ideXlab platform.
-
stpp spatial Temporal Phase profiling based method for relative rfid tag localization
IEEE ACM Transactions on Networking, 2017Co-Authors: Longfei Shangguan, Zheng Yang, Alex X Liu, Zimu Zhou, Yunhao LiuAbstract:Many object localization applications need the relative locations of a set of objects as oppose to their absolute locations. Although many schemes for object localization using radio frequency identification (RFID) tags have been proposed, they mostly focus on absolute object localization and are not suitable for relative object localization because of large error margins and the special hardware that they require. In this paper, we propose an approach called spatial-Temporal Phase profiling (STPP) to RFID-based relative object localization. The basic idea of STPP is that by moving a reader over a set of tags during which the reader continuously interrogating the tags, for each tag, the reader obtains a sequence of RF Phase values, which we call a Phase profile, from the tag’s responses over time. By analyzing the spatial-Temporal dynamics in the Phase profiles, STPP can calculate the spatial ordering among the tags. In comparison with prior absolute object localization schemes, STPP requires neither dedicated infrastructure nor special hardware. We implemented STPP and evaluated its performance in two real-world applications: locating misplaced books in a library and determining the baggage order in an airport. The experimental results show that STPP achieves about 84% ordering accuracy for misplaced books and 95% ordering accuracy for baggage handling. We further leverage the controllable reader antenna and upgrade STPP to infer the spacing between each pair of tags. The result shows that STPP could achieve promising performance on distance ranging.
-
relative localization of rfid tags using spatial Temporal Phase profiling
Networked Systems Design and Implementation, 2015Co-Authors: Longfei Shangguan, Zheng Yang, Alex X Liu, Zimu Zhou, Yunhao LiuAbstract:Many object localization applications need the relative locations of a set of objects as oppose to their absolute locations. Although many schemes for object localization using Radio Frequency Identification (RFID) tags have been proposed, they mostly focus on absolute object localization and are not suitable for relative object localization because of large error margins and the special hardware that they require. In this paper, we propose an approach called Spatial-Temporal Phase Profiling (STPP) to RFID based relative object localization. The basic idea of STPP is that by moving a reader over a set of tags during which the reader continuously interrogating the tags, for each tag, the reader obtains a sequence of RF Phase values, which we call a Phase profile, from the tag's responses over time. By analyzing the spatial-Temporal dynamics in the Phase profiles, STPP can calculate the spatial ordering among the tags. In comparison with prior absolute object localization schemes, STPP requires neither dedicated infrastructure nor special hardware. We implemented STPP and evaluated its performance in two real-world applications: locating misplaced books in a library and determining baggage order in an airport. The experimental results show that STPP achieves about 84% ordering accuracy for misplaced books and 95% ordering accuracy for baggage handling.
Longfei Shangguan - One of the best experts on this subject based on the ideXlab platform.
-
stpp spatial Temporal Phase profiling based method for relative rfid tag localization
IEEE ACM Transactions on Networking, 2017Co-Authors: Longfei Shangguan, Zheng Yang, Alex X Liu, Zimu Zhou, Yunhao LiuAbstract:Many object localization applications need the relative locations of a set of objects as oppose to their absolute locations. Although many schemes for object localization using radio frequency identification (RFID) tags have been proposed, they mostly focus on absolute object localization and are not suitable for relative object localization because of large error margins and the special hardware that they require. In this paper, we propose an approach called spatial-Temporal Phase profiling (STPP) to RFID-based relative object localization. The basic idea of STPP is that by moving a reader over a set of tags during which the reader continuously interrogating the tags, for each tag, the reader obtains a sequence of RF Phase values, which we call a Phase profile, from the tag’s responses over time. By analyzing the spatial-Temporal dynamics in the Phase profiles, STPP can calculate the spatial ordering among the tags. In comparison with prior absolute object localization schemes, STPP requires neither dedicated infrastructure nor special hardware. We implemented STPP and evaluated its performance in two real-world applications: locating misplaced books in a library and determining the baggage order in an airport. The experimental results show that STPP achieves about 84% ordering accuracy for misplaced books and 95% ordering accuracy for baggage handling. We further leverage the controllable reader antenna and upgrade STPP to infer the spacing between each pair of tags. The result shows that STPP could achieve promising performance on distance ranging.
-
relative localization of rfid tags using spatial Temporal Phase profiling
Networked Systems Design and Implementation, 2015Co-Authors: Longfei Shangguan, Zheng Yang, Alex X Liu, Zimu Zhou, Yunhao LiuAbstract:Many object localization applications need the relative locations of a set of objects as oppose to their absolute locations. Although many schemes for object localization using Radio Frequency Identification (RFID) tags have been proposed, they mostly focus on absolute object localization and are not suitable for relative object localization because of large error margins and the special hardware that they require. In this paper, we propose an approach called Spatial-Temporal Phase Profiling (STPP) to RFID based relative object localization. The basic idea of STPP is that by moving a reader over a set of tags during which the reader continuously interrogating the tags, for each tag, the reader obtains a sequence of RF Phase values, which we call a Phase profile, from the tag's responses over time. By analyzing the spatial-Temporal dynamics in the Phase profiles, STPP can calculate the spatial ordering among the tags. In comparison with prior absolute object localization schemes, STPP requires neither dedicated infrastructure nor special hardware. We implemented STPP and evaluated its performance in two real-world applications: locating misplaced books in a library and determining baggage order in an airport. The experimental results show that STPP achieves about 84% ordering accuracy for misplaced books and 95% ordering accuracy for baggage handling.
Zhenxing Wang - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Phase mask encrypted optical steganography carried by amplified spontaneous emission noise
Optics Express, 2014Co-Authors: Ben Wu, Bhavin J Shastri, Matthew P Chang, Nicholas A Frost, Zhenxing Wang, Paul R PrucnalAbstract:A Temporal Phase mask encryption method is proposed and experimentally demonstrated to improve the security of the stealth channel in an optical steganography system. The stealth channel is protected in two levels. In the first level, the data is carried by amplified spontaneous emission (ASE) noise, which cannot be detected in either the time domain or spectral domain. In the second level, even if the eavesdropper suspects the existence of the stealth channel, each data bit is covered by a fast changing Phase mask. The Phase mask code is always combined with the wide band noise from ASE. Without knowing the right Phase mask code to recover the stealth data, the eavesdropper can only receive the noise like signal with randomized Phase.
-
Improving the privacy of optical steganography with Temporal Phase masks
Optics express, 2010Co-Authors: Zhenxing Wang, Mable P. Fok, John Chang, Paul R PrucnalAbstract:Temporal Phase modulation of spread stealth signals is proposed and demonstrated to improve optical steganography transmission privacy. After Phase modulation, the Temporally spread stealth signal has a more complex spectral-Phase-Temporal relationship, such that the original Temporal profile cannot be restored when only dispersion compensation is applied to the Temporally spread stealth signals. Therefore, it increases the difficulty for the eavesdropper to detect and intercept the stealth channel that is hidden under a public transmission, even with a correct dispersion compensation device. The experimental results demonstrate the feasibility of this approach and display insignificant degradation in transmission performance, compared to the conventional stealth transmission without Temporal Phase modulation. The proposed system can also work without a clock transmission for signal synchronization. Our analysis and simulation results show that it is difficult for the adversary to detect the existence of the stealth transmission, or find the correct Phase mask to recover the stealth signals.
