Author Affiliations
Abstract
1 Northwestern Polytechnical University, School of Physical Science and Technology, Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, Shaanxi Key Laboratory of Optical Information Technology, Xi’an, China, 710129
2 Nanjing University of Posts and Telecommunications, College of Electronic and Optical Engineering & College of Microelectronics, Nanjing, China, 210046
3 Aalto University, Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto, Finland
Chirp-free solitons have been mainly achieved with anomalous-dispersion fiber lasers by the balance of dispersive and nonlinear effects, and the single-pulse energy is constrained within a relatively small range. Here, we report a class of chirp-free pulse in normal-dispersion erbium-doped fiber lasers, termed birefringence-managed soliton, in which the birefringence-related phase-matching effect dominates the soliton evolution. Controllable harmonic mode locking from 5 order to 85 order is obtained at the same pump level of ~10 mW with soliton energy fully tunable beyond ten times, which indicates a new birefringence-related soliton energy law, which fundamentally differs from the conventional soliton energy theorem. The unique transformation behavior between birefringence-managed solitons and dissipative solitons is directly visualized via the single-shot spectroscopy. The results demonstrate a novel approach of engineering fiber birefringence to create energy-tunable chirp-free solitons in normal-dispersion regime and open new research directions in fields of optical solitons, ultrafast lasers, and their applications.
Ultrafast Science
2022, 2(1): 9760631
红外与毫米波学报
2022, 41(6): 1002
Author Affiliations
Abstract
1 Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and Its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
2 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
3 School of Electronic & Information Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
An AgGeSbTe thin film is proposed as a negative heat-mode resist for dry lithography. It possesses high etching selectivity with the etching rate difference of as high as 62 nm/min in mixed gases. The etched sidewall is steep without the obvious lateral corrosion. The lithographic characteristics and underlying physical mechanisms are analyzed. Besides, results of X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy further indicate that laser irradiation causes the formation of Ge, Sb, and AgTe crystals, which is the basis of etching selectivity. In addition, the etching selectivity of Si to AgGeSbTe resist is as high as 19 at mixed gases, possessing good etching resistance. It is believed that the AgGeSbTe thin film is a promising heat-mode resist for dry lithography.
thin film heat-mode resist lithography Chinese Optics Letters
2022, 20(3): 031601
Author Affiliations
Abstract
Key Laboratory of Optical Fiber Sensing and Communications, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
A pre-coding-assisted power detection scheme for radio over fiber downlink is presented. This scheme can eliminate laser phase noise while avoiding high energy-consuming electrical carrier required in conventional power and/or envelope detection schemes. Theoretical analysis and experimental verification are performed. 0.625 Gbaud pre-coded quadrature phase-shift keying or 16 quadrature amplitude modulation signals can both be recovered by power detection without electrical carrier assistance at the receiver after 75 km fiber transmission. Not only robust against the laser phase noise, an improvement of about 5 dB in receiver sensitivity can also be achieved, as compared with the conventional power detection scheme.
060.2330 Fiber optics communications 060.5625 Radio frequency photonics 060.2840 Heterodyne Chinese Optics Letters
2019, 17(11): 110602
Author Affiliations
Abstract
1 State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China
2 School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore
Ultrathin corrugated metallic structures have been proved to support spoof surface plasmon polariton (SPP) modes on two-dimension (2D) planar microwave circuits. However, to provide stronger field confinement, larger width of strip is required to load deeper grooves, which is cumbersome in modern large-scale integrated circuits and chips. In this work, a new spoof SPP transmission line (TL) with zigzag grooves is proposed. This new structure can achieve stronger field confinement compared to conventional one with the same strip width. In other words, the proposed spoof SPP TL behaves equivalently to a conventional one with much larger size. Dispersion analysis theoretically indicates the negative correlation between the ability of field confinement and cutoff frequencies of spoof SPP TLs. Numerical simulations indicate that the cutoff frequency of the proposed TL is lower than the conventional one and can be easily modified with the fixed size. Furthermore, two samples of the new and conventional spoof SPP TLs are fabricated for experimental demonstration. Measured S-parameters and field distributions verify the ultra-strong ability of field confinement of the proposed spoof SPP TL. Hence, this novel spoof SPP structure with ultra-strong field confinement may find wide applications in microwave and terahertz engineering.
ultrathin corrugated metallic structure surface plasmon polaritons field confinement zigzag grooves Opto-Electronic Advances
2019, 2(6): 190001
1 电子科技大学信息与通信工程学院, 四川 成都 610054
2 航空工业成都飞机设计研究所, 四川 成都 610091
针对传统故障识别方法过程复杂、用时长、准确率低等问题,提出了一种基于小波包分析和支持向量机的光纤故障自动识别方法。对光时域反射仪采集的数据进行事件点定位,选择最优基小波和尺度完成事件信号的分解和重构,提取归一化的小波包能量作为事件信号的特征向量;建立支持向量机模型,将特征向量作为输入进行训练和测试,最终实现故障识别。实验对机载光缆中由连接器引起的反射事件和弯折引起的非反射事件进行二分类测试,总样本数为2500。实验结果表明,当训练样本数为1750,测试样本数为750时,该方法对机载光纤中反射事件和非反射事件的正确识别率为99%,耗时3.03 s;与基于反向传播神经网络的识别方法相比,准确率提升了2%,且耗时仅为其1%左右。目前已成功应用于自主研发的机载光缆组件外场检测设备。
信号处理 光时域反射仪 小波包 特征提取 支持向量机 模式识别 激光与光电子学进展
2019, 56(2): 021205
Author Affiliations
Abstract
Key Laboratory of Optical Fiber Sensing and Communications, Ministry of Education, University of Electronic Science and Technology of China, Chengdu 611731, China
We propose and investigate the use of a Kramers–Kronig (KK) receiver in a single sideband orthogonal frequency division multiplexing radio over fiber (SSB-OFDM-RoF) link based on an optical remote heterodyne solution. This scheme is effective in eliminating the signal-to-signal beating interference introduced by square-law detection of a photo-detector in an SSB-OFDM-RoF link. We extensively study the influences of different carrier-to-signal power ratios (CSPRs), laser linewidths, and transmission distances on our proposed scheme. It is proved that the KK-based receiver can reduce optimal CSPR by more than 5 dB and provide about 1.1 dB gain over the conventional mixer-based receiver scheme with CSPR of 11 dB after 75 km fiber transmission.
060.5625 Radio frequency photonics 060.2330 Fiber optics communications Chinese Optics Letters
2019, 17(1): 010605
Author Affiliations
Abstract
1 College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210046, China
2 Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China
3 e-mail: xuxx@njnu.edu.cn
Low-dimensional nanomaterials, owing to their unique and versatile properties, are very attractive for enormous electronic and optoelectronic applications. PbS quantum dots (QDs), characterized by a large Bohr radius and size-tunable bandgap, are especially interesting for photonic applications in the near-infrared region. Here, oleic acid capped colloidal PbS QDs as a saturable absorber are investigated for ultrashort-pulse generation. The PbS QDs exhibit outstanding nonlinear saturable absorption properties at 1550 nm: a modulation depth up to 44.5% and a thermal damage threshold larger than 30 mJ/cm2. By incorporating PbS QDs into a fiber laser, a transform-limited soliton pulse as short as 559 fs with a bandwidth of 4.78 nm is realized at 1563 nm. Numerous applications may benefit from the nonlinear saturable absorption properties of PbS QDs, such as near-infrared pulsed lasers and modulators.
Photonics Research
2018, 6(11): 11001028
1 电子科技大学 光纤传感与通信教育部重点实验室, 成都 610054
2 西南石油大学 电气信息学院, 成都 610500
反射型量子点半导体光放大器(R-QDSOA)相较于传统RSOA具有皮秒级的载流子恢复速率和几十GHz的调制带宽, 将其应用在高速的波分复用无源光网络(WDM-PON)中具有巨大的潜力. 根据R-QDOSA的载流子速率方程和光场传输方程, 建立了R-QDSOA的仿真模型, 对其在增益饱和情况下的高通特性进行研究. 研究结果表明: 通过增加输入光功率、最大模式增益、有源区长度和减小注入电流, 可提高最大信号增益和3 dB截止频率; 通过合理的参数设置, R-QDSOA的3 dB截止频率可高达10GHz以上. 该研究在无色WDM-PON的再调制方面展现了巨大的优势, 并对提高R-QDSOA调制带宽具有理论指导意义.
光电子学 无源光网络 速率方程 反射型量子点半导体光放大器 高通滤波 增益饱和 带宽 无色 Optoelectronics Passive optical networks Rate equations Reflective quantum-dot semiconductor optical ampli High-pass filters Gain saturation Bandwidth Colorless
1 电子科技大学 光纤传感与通信教育部重点实验室, 成都 611731
2 西南石油大学 电气工程与信息学院, 成都 637001
为了实现高速光信号的降速处理, 提出了一种基于级联半导体光放大器环镜(SLALOM)的光串并转换器, 用于实现将高速串行光脉冲信号转换成低速并行光脉冲信号.该光串并转换器采用串联SLALOM组成, 将前一级SLALOM的输出作为后一级SLALOM的输入; SLALOM之间的光传播时延为输入光信号比特周期; 设置控制光与信号光脉冲时序, 实现各级SLALOM光脉冲并行输出.通过采用1×10光串并转换器实现将80 Gb/s串行信号转换为10路8 Gb/s并行信号, 并对控制、信号脉冲光功率和时间偏移量器件参量进行了优化.对于1×10光串并转换器, 端口接收灵敏度差异小于10 dB.该光串并转换器光功率损耗小、易于扩展并行端口数目, 可用于光通信领域中的高速解复用、光信号处理和光交换系统中.
串并转换 半导体光放大器环镜 光纤通信 解复用 光信号处理 Serial-to-parallel conversion Semiconductor laser amplifier in a loop mirror Optical fiber communication Demultiplexing Optical signal processing
