Author Affiliations
Abstract
1 State Key Laboratory on Tunable Laser Technology, School of Electronic and Information Engineering, Harbin Institute of Technology, Shenzhen 518055, China
2 LTCI, Telecom Paris, Institut Polytechnique de Paris, 91120 Palaiseau, France
3 DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
4 School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
5 Center for High Technology Materials, The University of New-Mexico, Albuquerque, New Mexico 87106, USA
This work experimentally and theoretically demonstrates the effect of excited state lasing on the reflection sensitivity of dual-state quantum dot lasers, showing that the laser exhibits higher sensitivity to external optical feedback when reaching the excited state lasing threshold. This sensitivity can be degraded by increasing the excited-to-ground-state energy separation, which results in a high excited-to-ground-state threshold ratio. In addition, the occurrence of excited state lasing decreases the damping factor and increases the linewidth enhancement factor, which leads to a low critical feedback level. These findings illuminate a path to fabricate reflection-insensitive quantum dot lasers for isolator-free photonic integrated circuits.
Photonics Research
2023, 11(10): 1713
红外与激光工程
2022, 51(3): 20220087
1 深圳新飞通光电子技术有限公司,广东 深圳 518057
2 哈尔滨工业大学 深圳研究生院,广东 深圳 518055
外腔激光器具有窄线宽、低功耗的特征,主要用于相干光通信,实际应用中外腔激光器的输出光功率会在环境温度为高温或者低温时出现下降现象。通过使用有限元商用软件Ansys分析,发现高低温下机械结构会有微小的挠度变化,相较于常温,高低温下最大的挠度角度为0.04°。外腔激光器的腔长较长,结合光路仿真软件Zemax研究发现,微小的挠度变化会引起较大的光路变化,影响耦合效率,进而导致输出光功率降低。通过实验量测证实了光路变化,并基于挠度变化引起功率降低的理论,从设计角度提出了通过缩短腔长、加厚基座的方式来减小输出光功率随环境温度的变化。提出的模型与思路可以为类似产品的功率温度相关性分析提供量化分析思路。
外腔激光器 挠度变化 光路 功率变化 external cavity laser deflection change optical path power change
哈尔滨工业大学(深圳)电子信息与工程学院, 广东 深圳 518055
为应对概率整形场景下相干光通信系统中的偏振解复用问题,提出了一种基于独立成分分析和极大似然估计的偏振解复用算法。由于各个信号之间相互独立,因此可以对信号采用独立成分分析的手段进行偏振解复用。通过基于最大似然估计的迭代更新寻找最佳的分离矩阵,即偏振解复用矩阵。对所提算法在不同信噪比下的性能及整形强度的容忍度进行了仿真分析。结果表明,所提算法能够应对不同的概率整形强度,在较大的信噪比范围内均能完成良好的偏振解复用。相较于用于标准信号的恒模算法,所提算法并不会受到整形强度的影响,并且随着整形强度的增加,系统的性能有所提升。
光通信 概率整形 偏振解复用 独立成分分析
Author Affiliations
Abstract
1 Department of Electronic & Information Engineering, Harbin Institute of Technology, Shenzhen 518055, China
2 State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
3 e-mail: dujiangbing@sjtu.edu.cn
4 e-mail: kxu@hit.edu.cn
Recently, 2-μm wave band has gained increasing interest due to its potential application for next-generation optical communication. But the development of 2-μm optical communications is substantially hampered by the modulation speed due to the device bandwidth constraints. Thus, a high-speed modulator is highly demanded at 2 μm. Motivated by this prospect, we demonstrate a high-speed silicon Mach–Zehnder modulator for a 2-μm wave band. The device is configured as a single-ended push–pull structure with waveguide electrorefraction via the free carrier plasma effect. The modulator was fabricated via a multiproject wafer shuttle run at a commercial silicon photonic foundry. The modulation efficiency of a single arm is measured to be . The high-speed characterization is also performed, and the modulation speed can reach 80 Gbit/s with 4-level pulse amplitude modulation (PAM-4) formats.
Photonics Research
2021, 9(4): 04000535
Author Affiliations
Abstract
School of Electronics and Information Engineering, Harbin Institute of Technology, Shenzhen 518055, China
A fiber-optic sensor for the simultaneous measurement of strain and temperature is proposed and experimentally demonstrated based on Fabry–Pérot (FP) interference and the antiresonance (AR) mechanism. The sensor was implemented using a single-mode fiber (SMF)–hollow-core fiber–SMF structure. A temperature sensitivity of 21.11 pm/°C was achieved by tracing the troughs of the envelope caused by the AR mechanism, and a strain sensitivity of 2 pm/με was achieved by detecting the fine fringes caused by the FP cavity. The results indicate that the dual-parameter sensor is stable and reliable.
fiber-optic sensor Fabry–Pérot interference antiresonance Chinese Optics Letters
2021, 19(4): 041201
哈尔滨工业大学(深圳)电子信息与工程学院, 广东 深圳 518055
为应对概率整形场景下载波相位恢复的问题,提出了一种基于统计分析的自适应算法。利用核密度估计进行概率整形信号的参数估计,从而估计得到信息熵,以辅助后续的基于半径定向的4次方频偏估计算法。运用估计出的概率整形参量进行信号的针对性归一化,用于后续基于盲相位搜索的载波相位噪声恢复。对该算法的频偏估计范围、信噪比及激光线宽容忍度进行了仿真分析。结果表明,所提方案能够应对不同的概率整形强度,在较大的信噪比范围内均能实现良好的载波相位恢复。此外,相对于用于标准信号的载波相位恢复算法,该方案达到最优性能时所需的滑动窗口长度更短并且拥有更高的估计精度。
光通信 概率整形 载波相位恢复 核密度估计 光学学报
2020, 40(23): 2306001
Author Affiliations
Abstract
1 School of Electronic and Information Engineering, Harbin Institute of Technology, Shenzhen 518055, China
2 Han’s Laser Technology Industry Group Co., Ltd., Shenzhen 518055, China
3 Sino-German College of Intelligent Manufacturing, Shenzhen Technology University, Shenzhen 518118, China
The ultimate capacity of a cladding-pumped 10/130 Tm:fiber is experimentally investigated with a 793 nm laser diode bidirectionally pumped amplifier. The laser system works stably at the output powers of 52 W, 65 W, and 87 W. Eventually, the damage of the amplifier occurs when the output power reaches about 103.5 W with a total incident pump power of 176.8 W. Considering the incident seed power of 12.3 W, the amplifier conversion efficiency is estimated to be about 51.6% before it is damaged. With valuable exploration, we achieve the first air-cooling 60 W Tm:fiber laser at 1945.845 nm with a spectral linewidth of 0.4 nm. The laser power stability reaches 1.24% during a continuous test time of >65 h. The beam quality is measured as and .
double cladding Tm:fiber all-fiber laser Chinese Optics Letters
2020, 18(5): 051404
1 深圳市太赫兹科技创新研究院, 广东 深圳 518102
2 哈尔滨工业大学 深圳研究生院 激光信息技术研究中心, 广东 深圳 518055
太赫兹光电导天线广泛应用于宽带脉冲太赫兹波的检测, 是太赫兹光谱和成像系统中的重要器件。偶极子光电导天线由于其结构简单、制作容易成为使用最广泛的一类太赫兹光电导接收天线。衡量太赫兹光电导探测天线的一个重要指标是其响应带宽。针对偶极子天线的探测带宽, 分别对天线臂长为10、50、150 μm的偶极子天线及一种作为对比的178 μm的蝶形天线(Bowtie antenna)进行了实验及理论研究。结果显示其探测带宽随天线臂长增加而减小, 与微波天线理论一致。进一步的, 采用商用电磁场数值仿真软件进行建模仿真, 仿真结果与理论及实验结果具有很好的一致性, 证实数值仿真已在很大程度上模拟出实际天线的特性, 从而为优化结构参数制作大宽带和高灵敏度的太赫兹天线提供支持。同时, 对超半球硅衬底透镜对天线接收频谱的影响也进行了探讨。
太赫兹 光电导天线 太赫兹时域光谱 太赫兹探测器 terahertz photoconductive antenna terahertz time-domain spectroscopy terahertz detector 红外与激光工程
2019, 48(1): 0125002
1 深圳市太赫兹科技创新研究院,广东 深圳 518102
2 哈尔滨工业大学 深圳研究生院,广东 深圳 518055
3 中国工程物理研究院 电子工程研究所,四川 绵阳 621999
为开发紧凑、轻质量、高稳定度的光纤耦合太赫兹时域光谱仪(THz-TDS),从色散补偿、非线性效应、偏振效应、天线参数等方面对基于1 550 nm波长的光纤飞秒激光器激发的太赫兹时域光谱系统进行理论及实验研究。结果显示,光纤耦合的光谱仪光谱带宽可达4.5 THz,动态范围达70 dB,质量12.3 kg,光路模块体积250 mm×90 mm×50 mm。进一步测试机械振动及环境温度对仪器的影响,在一定范围内,仪器具有较高的鲁棒性,可适应工业产业应用需求。
太赫兹 太赫兹时域光谱 光纤飞秒激光 terahertz Terahertz Time-Domain Spectroscopy fiber femtosecond laser 太赫兹科学与电子信息学报
2018, 16(6): 943