Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
2 The 41st Institute of China Electronics Technology Group Corporation, Qingdao, China
We report a compact, tunable, self-starting, all-fiber laser-based asynchronous optical sampling (ASOPS) system. Two Er-doped fiber oscillators were used as the pulsed-laser source, whose repetition rate could be set at 100 MHz with a tuning range of 1.25 MHz through a fiber delay line. By employing phase-locked and temperature control loops, the repetition rate offset of the two lasers was stabilized with 7.13 × 10-11 fractional instability at an average time of 1 s. Its capabilities in the terahertz regime were demonstrated by terahertz time-domain spectroscopy, achieving a spectral bandwidth of 3 THz with a dynamic range of 30 dB. The large range of repetition rate adjustment in our ASOPS system has the potential to be a powerful tool in the terahertz regime.
asynchronous optical sampling mode-locked fiber laser terahertz time-domain spectroscopy High Power Laser Science and Engineering
2023, 11(2): 02000e29
Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
2 Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
3 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
A multi-channel laser interferometer (MCLI) is proposed to improve the coordinate measurement accuracy. A 780 nm external cavity laser is locked on the D2 line of 87Rb atom by polarization spectroscopy, and a high frequency stabilized laser source is obtained with a linewidth of 385.8 kHz at root mean square (RMS). The interferometers share the stabilized source and individually install on 4 axes of a coordinate measuring system. As a result, the measurement uncertainty is reduced from 1.2 μm to 0.2 μm within the dynamic measurement range of 1.0 m. The MCLI is adept at integrate and flexible installation, which caters to various applications on precision measurement.
光电子快报（英文版）
2022, 18(10): 588
1 华东师范大学精密光谱科学与技术国家重点实验室，上海 200062
2 山西大学极端光学协同创新中心，山西 太原 030006
3 中国电子科技集团公司第四十一研究所电子测试科学技术实验室，山东 青岛 266000
提出了一种可编程的激光脉冲选取和幅度控制的方法，以产生具有任意时域波形的脉冲串模式激光。采用具有灵活的可编程性的基于现场可编程门阵列结构的脉冲选择单元驱动声光调制器，实现对脉冲串内每个激光脉冲能量的精确控制。基于该创新的脉冲时域特性调控技术，利用掺镱啁啾脉冲光纤放大系统，实现了不同时域波形的高能量激光脉冲串，脉冲串能量为20 μJ，脉冲串间重复率为1 MHz，脉冲串内单脉冲宽度小于300 fs。
激光光学 超快激光器 光纤激光 脉冲整形 激光与光电子学进展
2021, 58(23): 2314001
Author Affiliations
Abstract
State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai200062, China
Gain-parameter-dependent transfer functions and phase-noise performances in a mode-locked Yb-doped fiber laser are measured in this study. It is discovered that the corner frequency in the amplitude and phase domains is determined by the absorption coefficient of the gain fiber, when the total absorption and other cavity parameters are fixed. This shows that an oscillator using gain fiber with higher dopant concentration accumulates more phase noise. Furthermore, we present net cavity dispersion-dependent transfer functions to verify the effect of dispersion management on the frequency response. We derive a guideline for optimizing mode-locked fiber laser design to achieve low phase noise and timing jitter.
mode-locked fiber laser phase noise transfer function High Power Laser Science and Engineering
2021, 9(3): 03000e36
Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
2 Key Laboratory of Optoelectronic Information Science and Technology of Ministry of Education, Tianjin University, Tianjin 300072, China
Dual-comb spectroscopy is a powerful spectroscopic tool with ultrahigh-resolution, high-sensitivity properties, which opens up opportunities for the parallel detection of multi-species molecules. However, in its conventional form, highly stable laser combs with sophisticated control systems are required to perform dual-comb spectroscopy. Here, a passive mutually coherent dual-comb spectroscopy system via an optical-optical modulation method is addressed, where all fast phase-locking electronics are retired. Without post computer-based phase-correction, a high degree of mutual coherence between the two combs with a relative comb-tooth linewidth of 10 mHz is achieved, corresponding to a coherent time of 100 s. To demonstrate the performance and versatility of the system, the dual comb spectrometer is applied to record the mode-resolved single molecular spectra as well as parallel detected spectra of mixed gases including CO2, CO and C2H2 that well agree with the established spectral parameters. Our technique exhibits flexible wavelength tuning capability in the near-infrared region and can be potentially extended to the mid-infrared region for more applications.
Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai200062, China
2 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan030006, China
3 Science and Technology on Electronic Test & Measurement Laboratory, The 41st Research Institute of CETC, Qingdao266000, China
We report on the generation of a mid-infrared (mid-IR) frequency comb with a maximum average output power of 250 mW and tunability in the 2.7–4.0 μm region. The approach is based on a single-stage difference frequency generation (DFG) starting from a compact Yb-doped fiber laser system. The repetition rate of the near-infrared (NIR) comb is locked at 75 MHz. The phase noise of the repetition rate in the offset-free mid-IR comb system is measured and analyzed. Except for the intrinsic of NIR comb, environmental noise at low frequency and quantum noise at high frequency from the amplifier chain and nonlinear spectral broadening are the main noise sources of broadening the linewidth of comb teeth, which limits the precision of mid-IR dual-comb spectroscopy.
fiber laser mid-infrared optical frequency comb High Power Laser Science and Engineering
2020, 8(4): 04000e32
Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
2 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
We report on a compact and robust self-referenced optical frequency comb with a tunable repetition rate, generated by an all-polarization-maintaining (PM) mode-locked Er-doped fiber laser. The spacing between comb teeth can be tuned above 300 kHz at a repetition rate of 101 MHz. The repetition rate and the carrier–envelope offset of the laser are stabilized separately, and the relative residual phase noises are determined to be $336~\unicode[STIX]{x03BC}\text{rad}$ and 713 mrad (1 Hz–1 MHz). The accurate frequency characteristics and the stable structure show great potential for the use of such a comb in applications of precision measurements.
optical frequency comb all-polarization-maintaining mode-locking fiber laser High Power Laser Science and Engineering
2020, 8(2): 02000e17
为实现四旋翼无人机自主飞行、定点悬停和跟踪地面目标的系统设计, 在系统中加入摄像头来采集地面信息, 进行相应的图像处理后, 所得结果结合视野的九宫格分割法, 可以获得待追寻目标位置信息。系统包含超声波定高模块, 将传统的无人机运动控制的六自由度简化为四自由度。采用将位置信息引入到PID控制系统中的方法, 获得四电机的控制命令, 进而实现前后左右的移动。此外, 运用双控制器, 一台控制器用于控制飞机运动, 另一台控制器用于控制系统的各个模块, 减少数据处理负担, 加快处理速度。最终, 实现预期的自主追踪效果, 与已有方法相比, 具有更简化的运动控制思路, 跟踪更灵敏。
四旋翼无人机 飞行控制 目标追踪 九宫格算法 PID算法 quad-rotor UVA flight control target tracking sudoku algorithm PID algorithm
