随着高速光通信信号速率的不断提高，电采样示波器所需的带宽也增加了。现有宽带高性能电采样示波器逐渐达到电子瓶颈决定的带宽极限。为了克服电子瓶颈，研制了基于光域采样技术的光采样示波器样机，其中软件同步算法的复杂度决定了样机测试的实时性。在基于啁啾z变换（CZT）的软件同步算法基础上，提出了基于选带傅里叶变换（ZoomFFT）的软件同步算法，进一步降低软件同步复杂度。与基于CZT的软件同步算法相比，基于ZoomFFT的软件同步算法所需实数乘法个数下降了68.8%。利用研制的光采样示波器样机，分别对不同速率的四电平脉冲幅度调制（PAM4）光信号、正交相移键控（QPSK）光信号进行了测量，并以宽带电采样示波器的测量结果进行对比，验证了光采样示波器能自适应地对不同速率的强度调制信号、相位调制信号进行测量。此外，为了表征光采样示波器本底噪声的影响，通过降低被测光通信信号功率，对Q因子进行了测量，结果表明，Q因子下降3 dB对应的灵敏度约为10 dB。
光纤通信 采样 眼图 Q因子 光学学报
2023, 43(15): 1506003
北京理工大学 光电学院 信息光子技术工信部重点实验室, 北京 100081
随着可见光通信的发展, 室内可见光定位技术获得了广泛的关注。在以图像传感器为接收终端的见光定位系统中, 针对单频率调制ID方案简单易实施, 但受限于接收终端采集频率上限, 可提供ID数量过少, 难以满足实际较大面积场景的应用需要。提出了一种扩展ID方法, 将两个不同频率的方波进行或运算, 输出信号加载到驱动端作为LED ID标识。采用普通商用手机开展了实验研究, 结果表明, 与使用单一以频率作为LED ID相比, 在本系统中可提供ID数量增加了6倍以上, 可提供153种ID, 且实验中识别ID准确率100%, 在LED灯具被遮挡的面积达到1/3时, 仍能正确识别出ID。
室内定位 可见光定位 双频率或运算 indoor position visible light position LED ID LED ID dual frequency square wave OR operation
Author Affiliations
Abstract
1 School of Optoelectronics, Beijing Institute of Technology, Beijing 100081, China
2 Key Laboratory of Photo-electronic Imaging Technology and System (Beijing Institute of Technology), Ministry of Education of China, Beijing 100081, China
Visible light positioning becomes popular recently. However, its performance is degraded by the indoor diffuse optical channel. An artificial neural-network-based visible light positioning algorithm is proposed in this Letter, and a trained neural network is used to achieve positioning with a diffuse channel. Simulations are made to evaluate the proposed positioning algorithm. Results show that the average positioning error is reduced about 13 times, and the positioning time is reduced about two magnitudes. Moreover, the proposed algorithm is robust with a different field-of-view of the receiver and the reflectivity of the wall, which is suitable for various positioning applications.
060.4510 Optical communications 200.4260 Neural networks 230.3670 Light-emitting diodes Chinese Optics Letters
2017, 15(5): 050601
Author Affiliations
Abstract
1 School of Optoelectronics, Beijing Institute of Technology, Beijing 100081, China
2 Key Laboratory of Photo-electronic Imaging Technology and System, Ministry of Education of China, Beijing 100081, China
Indoor visible light positioning becomes attractive due to the increasing demands of location-based services. This Letter proposes an indoor imaging visible light positioning scheme with a sampled sparse light source, image sensor, and gyro. An indoor positioning cellular with a single reference light source and an off-the-shelf mobile device is demonstrated. Experimental results show that the 3-dimensional positioning error is only several centimeters even with a rotated, rolled, and pitched mobile device. The proposed scheme is convenient and cost effective because the transmitter takes advantage of the existing lighting infrastructure and the receiver is a commercial mobile phone without any extra accessories.
060.4510 Optical communications 230.3670 Light-emitting diodes Chinese Optics Letters
2016, 14(9): 090602
Author Affiliations
Abstract
1 School of Opto-electronics, Beijing Institute of Technology, Beijing 100081, China
2 National Science and Technology Venture Capital Development Center, Beijing 100044, China
A combination of light-emitting diode (LED) identification and a time-division multiplexing scheme is proposed in this Letter for indoor location-based service. With the scheme, the arrangement of white LED lamps and the structure of a data frame are designed to realize high-accuracy indoor positioning and location-based payload data transmission simultaneously. The results of the experiment demonstrate that the indoor positioning accuracy is 10 cm and 2 Mb/s data transmission with high signal quality is realized.
060.4510 Optical communications 230.3670 Light-emitting diodes 040.5160 Photodetectors Chinese Optics Letters
2015, 13(12): 120601
基于周期极化铌酸锂波导的和频效应，研制了光采样示波器样机。通过实验研究了光采样示波器样机在不同条件(光信号功率、数据速率、色散、波长)下的测试性能，并与宽带电示波器的测试结果进行了对比，从多个方面对光采样示波器的测试性能进行了评估。与安捷伦86100A 示波器的对比测试结果表明，该光采样示波器样机具有更高的灵敏度，对弱信号测量具有更强的稳健性。对不同速率光信号测量的结果表明，光采样示波器样机能对不同速率信号自适应测量，真正实现数据速率透明化。在不同色散条件下的测量结果表明，光采样示波器样机能对光纤传输信号自适应测量。为了使光采样示波器样机对不同波长信道的光信号具有一致的测量性能，必须优化锁模脉冲激光器的光谱，使其光谱平坦。这些结果为光采样示波器的进一步优化设计和参数标定提供了很好的依据。
光通信 非线性光学 光纤光学 激光与光电子学进展
2015, 52(6): 060603
Author Affiliations
Abstract
School of Opto-electronics, Beijing Institute of Technology, Beijing100081, China
In an optical performance monitoring system for high-speed optical communications, the ultra-short optical pulse from the laser is divided into two parts. One is to sample high-speed optical communication signal and the other as the sampling clock in an analog/digital converter (ADC) after detecting using a photon-detector. We propose a simple method based on variance calculation to align the phase of sampling clock in an ADC. The experiments demonstrate that, with the proposed method, the eye diagram or constellation diagram of high-speed optical communication signal can be reconstructed by the optical performance monitoring system.
060.4510 Optical communications 060.2330 Fiber optics communications 060.1660 Coherent communications Chinese Optics Letters
2015, 13(1): 010606
Author Affiliations
Abstract
A tunable optical rail is embedded into the cavity of a nonlinear-polarization-rotation (NPR) mode-locked fiber laser to generate a sampling pulse with different repetition frequencies and realize bit-rate-adaptive software synchronous optical sampling. Two ultrashort pulses (20.26677 and 20.22900 MHz) are derived, and a 100-MHz data signal is sampled twice with these pulses based on sum-frequency generation (SFG) in periodically poled lithium niobate (PPLN). The eye diagram is successfully recovered, and an estimated bit rate of 102.22 MHz is derived. This method is feasible for bit rates ranging from 200 MHz to 1 GHz, with <3% relative error.
060.4370 Nonlinear optics, fibers 190.4360 Nonlinear optics, devices 070.4340 Nonlinear optical signal processing Chinese Optics Letters
2013, 11(5): 050603
Author Affiliations
Abstract
We investigate the multilevel modulation for red-green-blue light emitting diode (RGB LED). A simple approach for extracting soft values from the modulation is proposed. The mapping way from bits to the modulated symbols for the multilevel modulation is also investigated. The modified modulation is obtained through the brute force. Based on the Monte Carlo simulations, the proposed approach and modified modulation are confirmed and better bit error rate (BER) performances are obtained.
060.4510 Optical communications 040.5160 Photodetectors 230.3670 Light-emitting diodes Chinese Optics Letters
2013, 11(3): 030601
