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We present a powerful jitter analysis method for timing distribution systems based on feedback flow between setup elements. Our comprehensive feedback model yields excellent agreement with the experimental results and identifies seven uncorrelated noise sources.
We demonstrate an octave spanning coherent supercontinuum generated in a silicon waveguide covering the near to shortwave IR (SWIR) region. The measured −20 dB SC span ranges from 1.124 μm to 2.4 μm.
The spontaneous emission lifetime in Al2O3:Tm3+ waveguides is measured to be 568 ± 48 μs, using a frequency-domain method. The method is studied and verified in Er3+-doped silica fiber, yielding a measured lifetime of 9.73 ± 0.08 ms.
We describe two different schemes for residual phase noise measurement of a dual-link optical-microwave timing system. The lengths of the fiber links are 1.2 km and 3.5 km. The residual single-sideband (SSB) phase noise of 10.833 GHz local oscillators lays below −135 dBc at 10 kHz offset. The RMS jitter integrated from 1 Hz to 10 MHz does not exceed 3 fs.
We report on high-power CMOS-compatible thulium-doped distributed feedback and distributed Bragg reflector lasers with single-mode output powers up to 267 mW and 387 mW, and slope efficiencies of 14% and 23% respectively. More than 70 dB side-mode suppression ratio are achieved for both lasers. This work extends the applicability of silicon photonic microsystems into the 2 μm region.
To observe electronic dynamics in atoms, molecules, and condensed matter taking place on an attosecond time scale, next-generation photon science facilities like X-ray free-electron lasers and intense laser beamlines require system-wide attosecond-level synchronization of dozens of optical and microwave signals up to kilometer distances. Here, we present for the first time a timing synchronization...
In this paper, within the linear minimum mean square error (LMMSE) framework and with the Gaussian assumption, we propose a novel nonlinear estimation algorithm using a Hermite polynomial based uncorrelated conversion (UC), which is a nonlinear function of the original measurement while being uncorrelated with the original measurement. The UC can be regarded as a “new” measurement and additional information...
In a practical terminal guidance process, missile acceleration may be saturated and the saturation can lead to degraded interception performance. This paper presents an anti-saturation guidance law with finite-time convergence for a three-dimensional maneuvering interception, using the theories of finite-time boundedness (FTB) and input-output finite-time stability (IO-FTS). With this law, the line-of-sight...
We report a synchronous multi-color mode-locked laser network over 4.7-km distance. Output of two remotely synchronized lasers shows only 0.6-fs RMS drift over 40 hours reaching 20th decimal uncertainty in less than 10000-s averaging time.
We demonstrate a high precision microwave network over stabilized multi-kilometer fiber links. Relative phase jitter (>1Hz) and drift (<1Hz) between two remotely synchronized 10.83-GHz microwave sources are 77.9 and 119.6 μrad, respectively, over 2.5-hour operation.
A novel 4.7-km laser-microwave network continuously operating with attosecond precision over more than two days is demonstrated. This work enables clocking of future X-ray photon-science facilities now also with attosecond temporal resolution.
In this work, an autonomous surveillance system providing ultra wide angle (UWA) video information is presented using multi-UAV platform. Towards this end, a fleet of UAVs are initially deployed into appropriate formation (such as triangle, diamond, or line) with cameras pointing outwards to cover the region of interest (ROI). In aid of image processing technique, the UAVs formation will be further...
We report a high power CMOS-compatible thulium-doped distributed feedback laser with single-mode output power up to 267 mW, 14% slope efficiency, and >70dB side mode suppression ratio.
The paper presents a distributed estimation scheme based on a new batch covariance intersection (BCI) strategy and an average consensus algorithm to address the problem of data fusion in sensor networks. Due to sharing common prior knowledge, process noise and/or existence of correlated measurement noise, the error of the local estimates from each sensor node in a sensor network is correlated with...
Image stitching using small-scale unmanned aerial vehicles (UAVs) is investigated in this paper. A novel approach is presented to take advantage of the UAVs' position information to facilitate a full view of multiple images' stitching. Our ultimate goal is to generate an overview image as soon as possible and, at the meanwhile to achieve the most efficient usage of UAVs' resources. A feedback scheme...
In this paper, we study the stability of a thermal system with feedback control in which the sensor is modeled by a partial differential equation. The problem is motivated by the thermal management requirement in energy systems such as lithium ion batteries where the heating information must pass through a finite distance through conduction. The focus of this paper is to examine the stability issue...
We demonstrate a balanced optical-microwave phase detector (BOMPD) showing robust long-term optical-RF synchronization characteristics with sub-femtosecond residual timing drift over 24 hours under laboratory conditions without active temperature control of optical and electronic paths. Using this BOMPD, a 10.833 GHz Sapphire-loaded cavity oscillator (SLCO) was successfully disciplined by the pulse...
We report recent progress made in a synchronous multi-color mode-locked laser network over 4.7-km distance. Output of two remotely synchronized lasers shows only 0.6-fs RMS drift over 40 hours reaching 20th decimal uncertainty in less than 10000-s averaging time. This work will enable sub-fs synchronization of new generation photon science facilities and allow km-scale optical clock comparison with...
Space-borne synthetic aperture radar (SAR) is very useful due to the whole-day-work capability, which has been widely used in earthquake damage assessment and rescue. This paper presents a novel method for earthquake damage assessment by using multi-angle SAR images. The scatter of building, especially for the damaged buildings, will change with the elevation angle and squint angle, which means a...
As the Kerr constant of liquid medium is small, it is difficult to accurately detect the weak signals which from electric field measurement of transformer oil based on Kerr effect. To improve the accuracy of weak signal measurement, a weak signal measurement system was designed in this paper, which consists of signal channel module, reference channel module and phase sensitive detector module. The...
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