scholarly journals Error Correction for FSI-Based System without Cooperative Target Using an Adaptive Filtering Method and a Phase-Matching Mosaic Algorithm

2018 ◽  
Vol 8 (10) ◽  
pp. 1954 ◽  
Author(s):  
Xing-Ting Xiong ◽  
Xing-Hua Qu ◽  
Fu-Min Zhang
Keyword(s):  
Adaptive Filtering ◽  
Signal To Noise Ratio ◽  
Incident Angle ◽  
External Cavity ◽  
Phase Matching ◽  
Maximum Deviation ◽  
External Cavity Laser ◽  
Filtering Method ◽  
System A ◽  
Sampling Points

In our frequency scanning interferometry-based (FSI-based) absolute distance measurement system, a frequency sampling method is used to eliminate the influence of laser tuning nonlinearity. However, because the external cavity laser (ECL) has been used for five years, factors such as the mode hopping of the ECL and the low signal-to-noise ratio (SNR) in a non-cooperative target measurement bring new problems, including erroneous sampling points, phase jumps, and interfering signals. This article analyzes the impacts of the erroneous sampling points and interfering signals on the accuracy of measurement, and then proposes an adaptive filtering method to eliminate the influence. In addition, a phase-matching mosaic algorithm is used to eliminate the phase jump, and a segmentation mosaic algorithm is used to improve the data processing speed. The result of the simulation proves the efficiency of our method. In experiments, the measured target was located at eight different positions on a precise guide rail, and the incident angle was 12 degrees. The maximum deviation of the measured results between the FSI-based system and the He-Ne interferometer was 9.6 μm, and the maximum mean square error of our method was 2.4 μm, which approached the Cramer-Rao lower bound (CRLB) of 0.8 μm.

Vibration measurement with a micromachined mirror in a very-short external cavity laser

2004 ◽  
Vol 116 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Franck Chollet ◽  
Gopal M. Hegde ◽  
Zhang Xuming ◽  
Liu Aiqun ◽  
Anand Asundi
Keyword(s):  
External Cavity ◽  
Vibration Measurement ◽  
External Cavity Laser ◽  
Cavity Laser

scholarly journals Thermally Tuned High-performance III-V/Si3N4 External Cavity Laser

2021 ◽  
pp. 1-1
Author(s):  
Yuyao Guo ◽  
Ruiling Zhao ◽  
Gangqiang Zhou ◽  
Liangjun Lu ◽  
Anton Stroganov ◽  
...  
Keyword(s):  
High Performance ◽  
External Cavity ◽  
External Cavity Laser ◽  
Cavity Laser

Narrow-frequency sharp-angular filters using all-dielectric cascaded meta-gratings

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3443-3450 ◽  
Author(s):  
Wei-Nan Liu ◽  
Rui Chen ◽  
Wei-Yi Shi ◽  
Ke-Bo Zeng ◽  
Fu-Li Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Signal To Noise Ratio ◽  
Incident Angle ◽  
Design Strategy ◽  
Transmission Peak ◽  
High Signal ◽  
Waveguide Array ◽  
Signal To Noise ◽  
Center Wavelength ◽  
Noise Ratio

AbstractSelective transmission or filtering always responds to either frequency or incident angle, so as hardly to maximize signal-to-noise ratio in communication, detection and sensing. Here, we propose compact meta-filters of narrow-frequency sharp-angular transmission peak along with broad omnidirectional reflection sidebands, in all-dielectric cascaded subwavelength meta-gratings. The inherent collective resonance of waveguide-array modes and thin film approximation of meta-grating are employed as the design strategy. A unity transmission peak, locating at the incident angle of 44.4° and the center wavelength of 1550 nm, is demonstrated in a silicon meta-filter consisting of two-layer silicon rectangular meta-grating. These findings provide possibilities in cascaded meta-gratings spectroscopic design and alternative utilities for high signal-to-noise ratio applications in focus-free spatial filtering and anti-noise systems in telecommunications.

Deformation information extraction method based on differential synthetic aperture radar interferometry

2020 ◽  
Vol 39 (4) ◽  
pp. 5311-5318
Author(s):  
Zhengquan Hu ◽  
Yu Liu ◽  
Xiaowei Niu ◽  
Guoping Lei
Keyword(s):  
Remote Sensing ◽  
Synthetic Aperture Radar ◽  
Adaptive Filtering ◽  
Extraction Method ◽  
Deformation Monitoring ◽  
Radar Interferometry ◽  
Synthetic Aperture ◽  
Filtering Method ◽  
Synthetic Aperture Radar Interferometry ◽  
Aperture Radar

As aerospace technology, computer technology, network communication technology and information technology become more and more perfect, a variety of sensors for measurement and remote sensing are constantly emerging, and the ability to acquire remote sensing data is also continuously enhanced. Synthetic Aperture Radar Interferometry (InSAR) technology greatly expands the function and application field of imaging radar. Differential InSAR (DInSAR) developed based on InSAR technology has the advantages of high precision and all-weather compared with traditional measurement methods. However, DInSAR-based deformation monitoring is susceptible to spatiotemporal coherence, orbital errors, atmospheric delays, and elevation errors. Since phase noise is the main error of InSAR, to determine the appropriate filtering parameters, an iterative adaptive filtering method for interferogram is proposed. For the limitation of conventional DInSAR, to improve the accuracy of deformation monitoring as much as possible, this paper proposes a deformation modeling based on ridge estimation and regularization as a constraint condition, and introduces a variance component estimation to optimize the deformation results. The simulation experiment of the iterative adaptive filtering method and the deformation modeling proposed in this paper shows that the deformation information extraction method based on differential synthetic aperture radar has high precision and feasibility.

scholarly journals Widely-tunable, narrow-linewidth III-V/silicon hybrid external-cavity laser for coherent communication

2018 ◽  
Vol 26 (7) ◽  
pp. 7920 ◽  
Author(s):  
Hang Guan ◽  
Ari Novack ◽  
Tal Galfsky ◽  
Yangjin Ma ◽  
Saeed Fathololoumi ◽  
...  
Keyword(s):  
External Cavity ◽  
Narrow Linewidth ◽  
External Cavity Laser ◽  
Coherent Communication ◽  
Cavity Laser
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