Author Affiliations
Abstract
1 Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
2 Department of Engineering Physics, Tsinghua University, Beijing 100084, China
3 Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Tsinghua University, Beijing 100084, China
Coherent pulse stacking (CPS) is a new time-domain coherent addition technique that stacks several optical pulses into a single output pulse, enabling high pulse energy and high average power. A Z-domain model targeting the pulsed laser is assembled to describe the optical interference process. An algorithm, extracting the cavity phase and pulse phases from limited data, where only the pulse intensity is available, is developed to diagnose optical cavity resonators. We also implement the algorithm on the cascaded system of multiple optical cavities, achieving phase errors less than 1.0° (root mean square), which could ensure the stability of CPS.
070.2025 Discrete optical signal processing 120.5050 Phase measurement 140.4780 Optical resonators Chinese Optics Letters
2018, 16(4): 040701
华南农业大学电子工程学院, 广东 广州 510642
自干涉非相干数字全息可记录和再现非相干光源照明下物光场信息。但基于目前理论的重建算法对待测光场的不同纵向深度层面进行聚焦重构时，聚焦面信息会受到离焦层面光场信息的干扰。基于压缩感知理论，根据自干涉非相干数字全息的光学记录与再现过程，建立与该物理过程相适应的传感矩阵，从理论上构建实现光场分层重构的数值重建算法框架。基于自干涉非相干数字全息光路，以多个不同纵向深度的LED 点光源构建物光场，分别进行计算机数值模拟及实验研究，并且深入讨论光场层面再现距离与各实验参数之间的关系，指出增大各光场层面再现距离间差距的方法。理论及实验研究结果表明该方法可重构不同纵向深度层面的三维物光场，并有效抑制离焦层面光场信息的干扰。
全息 数字全息 离散光学信号处理 逆反问题 压缩感知
1 华南农业大学应用物理系, 广东 广州 510642
2 南阳师范学院物理与电子工程学院, 河南 南阳 473061
基于弱相干光源的数字全息，由于参考光和物光夹角在非常小的范围内才能观察到干涉条纹，因此该技术一般限制在同轴全息的范围之内，即采用相移法对多幅同轴全息图采集，不利于动态物体的观测与记录。引入压缩感知理论，结合数字全息重构算法，实现对单幅弱相干光数字全息图的数值重建，能有效抑制孪生像及相干噪声的干扰。给出详细的基于压缩感知的数值重建算法框架，并以发光二极管作为弱相干光源，基于数字全息实验光路，以分辨率测试标板为样品展开实验研究，说明该方法的有效性和可行性。
全息 离散光学信号处理 逆反问题 数字图像处理 激光与光电子学进展
2015, 52(10): 100901
Author Affiliations
Abstract
We propose a configuration of a wavelength division multiplexing (WDM)-visible light communication (VLC) system using orthogonal frequency division multiplexing (OFDM) modulation and an adaptive Nyquist windowing of the OFDM signal in the receiver. Based on this configuration, we demonstrate a 750-Mb/s WDM-VLC transmission based on RGB light-emitting diode (LED) with a distance of 70 cm. The measured bit error rate (BER) for all channels are under the pre-forward error correction limit of 3.8 \times 10-3. The BER performances of all the channels of the proposed WDM-VLC system show considerable improvement compared with those of the system without Nyquist windowing.
060.2605 Free-space optical communication 140.7300 Visible lasers 070.2025 Discrete optical signal processing Chinese Optics Letters
2013, 11(8): 080605
Author Affiliations
Abstract
The intensity and position of the coupling points in high birefringence (Hi-Bi) fibers can be detected effectively using distributed polarization coupling (DPC) detection. The detection sensitivity can decrease due to mechanical vibration disturbance and environment noise. Thus, a method based on empirical mode decomposition is proposed to detect weak mode coupling points. The simulation and experimental results illustrate that the proposed method can suppress the noise effectively and improve sensitivity significantly. The method can identify coupling points as weak as -60 dB embedded in noise automatically and effectively. The algorithm is applicable for DPC, and the experimental sensitivity is improved by 10 dB.
060.2420 Fibers, polarization-maintaining 070.2025 Discrete optical signal processing 060.2300 Fiber measurements 120.3180 Interferometry Chinese Optics Letters
2012, 10(4): 040603
Author Affiliations
Abstract
State Key Laboratory on Integrated Optoelectronics, Tsinghua National Laboratory for Information Science and Technology (TNList), Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
The performance of a novel all-optical sampling orthogonal frequency division multiplexing (OFDM) system is proposed and analyzed. Time delays and phase shifters are used to realize all optical forward/inverse discrete Fourier transform (DFT/IDFT). Different system configurations are tested and analyzed to optimize the performance, including the system capacity, modulation formats, DFT/IDFT constructions, and the width of the sample pulse. The 50- and 100-Gb/s real-time all-optical sampling (AOS) OFDM systems are investigated. All results are analyzed, and useful suggestions are offered for future high-speed applications.
全光采样正交频分复用 超短光脉冲 循环后缀 060.2330 Fiber optics communications 060.4230 Multiplexing 070.2025 Discrete optical signal processing Chinese Optics Letters
2011, 9(1): 010603
