1 北京信息科学与技术国家研究中心, 清华大学电子工程系, 北京 100084
2 武汉光电国家研究中心, 武汉 430074
高非线性光子晶体光纤具有小纤芯、大折射率对比度的特点,其周期性的空气孔结构使得导引声波布里渊散射(GAWBS)激发的声子被束缚在纤芯区域,产生显著的声光相互作用。声子通过调制光纤材料的折射率,从而对光波的相位进行调制。利用Sagnac干涉环将相位调制转化为强度调制,在光子晶体光纤中实现了1550 nm和1060 nm波段GAWBS声子的激发和探测。实验测得在1550 nm和1060 nm波长抽运下声子基模频率均约为1.24 GHz,验证了前向布里渊散射声子频率与抽运光波长无关的理论。
非线性光学 光子晶体光纤 导引声波布里渊散射 声子 Sagnac环
Author Affiliations
Abstract
Tsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
Compressive sampling (CS) has attracted considerable attention in microwave and radio frequency (RF) fields in recent years. It enables the acquisition of high-frequency signals at a rate much smaller than their Nyquist rates. Combined with photonics technology, traditional CS systems can significantly enlarge their operating bandwidth, which offers great potential for spectrum sensing in cognitive radios. In this Letter, we review our recent work on photonic CS systems for wideband spectrum sensing. First, a proof-of-concept photonics-assisted CS system is demonstrated; it is capable of acquiring numerous radar pulses in an instantaneous bandwidth spanning from 500 MHz to 5 GHz with a 500-MHz analog-to-digital converter (ADC). To further reduce the acquisition bandwidth, multi-channel photonics-assisted CS systems are proposed for the first time, enabling the acquisition of multi-tone signals with frequencies up to 5 GHz by using 120-MHz ADCs. In addition, the system bandwidth is increased from 5 to 20 GHz by employing time-interleaved optical sampling.
060.2360 Fiber optics links and subsystems 230.0250 Optoelectronics 060.5625 Radio frequency photonics Chinese Optics Letters
2017, 15(1): 010012
清华大学电子工程系信息科学与技术国家实验室, 北京 100084
利用零色散波长在1020 nm附近的光子晶体光纤(PCF)，对光纤光参量放大器(OPA)进行了研究。为了在较短的光纤中产生足够的参量增益，搭建了锁模掺镱光纤激光器作为抽运种子源，采用其具有高峰值功率的脉冲进行抽运。该激光器产生的短脉冲被放大后注入到PCF进行抽运。当抽运脉冲的中心波长接近光纤的零色散波长时，观测到了显著的参量增益。研究了不同抽运功率以及不同抽运波长下参量增益的变化，最高获得了23 dB的参量增益。
光纤光学 光子晶体光纤 光参量放大 四波混频 锁模激光器
1 清华大学电子工程系信息科学与技术国家实验室, 北京 100084
2 北京邮电大学电子工程学院信息光子学与光通信国家重点实验室, 北京 100876
报道了一种工作于1 μm波段、正常色散区、基于半导体可饱和吸收镜(SESAM)的被动锁模光纤激光器。激光器以高掺杂Yb光纤为增益物质，结合可调谐滤波器，形成环形腔结构。采用976 nm半导体激光器抽运，当抽运功率大于16 dBm时，激光器可实现1033~1069 nm波长范围内重复频率为25.4 MHz的宽带可调谐输出，性能稳定，在调谐范围内均可观测到非常规则的矩形输出光谱。在固定抽运功率下，对调谐范围内输出功率、光谱带宽、时域脉宽进行了实验测量和分析。在波长为1064 nm时，用单通道光栅对将谱宽为1.745 nm、时域脉宽为34.85 ps的脉冲压缩至15.45 ps。
光纤光学 光纤激光器 半导体可饱和吸收镜 可调谐 正色散 环形腔 脉冲压缩
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
Author Affiliations
Abstract
1 State Key Laboratory on Integrated Optoelectronics, Tsinghua National Laboratory for Information, Science, and Technology (TNList), Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
2 ENCS of Concordia University, Montreal, Canada
We propose and demonstrate experimentally a novel scheme to realize all-optical up-conversion and wavelength-conversion based on the bi-directional-pump four-wave mixing (FWM) effect in high nonlinear fibers (HNLFs). The pump is generated with optical carrier suppression in a Mach-Zehnder modulator. The two pumps are always parallel and phase-locked. A balance-detection photo-detector for optical signal detection is employed with 3-dB improvement in power penalty. The 2.5-Gb/s signals are transmitted successfully over the 25-km single-mode fiber in 30-GHz radio over fiber (ROF) systems.
全光上变频 四波混频 高非线性光纤 毫米波光纤无线系统 060.4370 Nonlinear optics, fibers 060.5625 Radio frequency photonics Chinese Optics Letters
2010, 8(11): 1037
Author Affiliations
Abstract
State Key Laboratory on Integrated Optoelectronics, Tsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
A phase pre-emphasis technique used in an all-optical sampling orthogonal frequency division multiplexing (AOS-OFDM) system is proposed and demonstrated. With the application of this technique, 50-Gb/s AOS-OFDM data are successfully transmitted over 20-km uncompensated single-mode fiber (SMF) with real-time direct-detection. The constructive interference effect between symbols is decreased with this technique.
全光采样正交频分复用 相位预加重 实时 060.2330 Fiber optics communications 060.4230 Multiplexing Chinese Optics Letters
2010, 8(9): 871
1 光纤通信技术和网络国家重点实验室 武汉光迅科技股份有限公司, 湖北 武汉430074
2 清华大学 电子工程系, 北京100084
单片集成可调谐半导体激光器的使用为光纤通信系统和智能光网络带来极大的灵活性、可扩展性以及经济性。文章综述了单片集成可调谐半导体激光器的调谐机制、结构特点以及性能比较, 概要介绍了最新研究进展情况, 分析了相关发展趋势和市场应用前景。
光子集成光路 可调谐半导体激光器 密集波分复用 智能光网络 photonic integrated circuit tunable laser diode DWDM agile optical network
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
A novel all-optical method for ultra-wideband (UWB) monocycle pulses generation based on cross polarization modulation (CPM) effect in highly nonlinear photonic crystal fiber is proposed and demonstrated. Due to the CPM effect between the probe light and the pump pulse, a pair of polarity-reversed Gaussian pulses is produced. After proper differential delay, an UWB monocycle pulse with 84-ps width and the fractional bandwidth of 153% is generated after photodetection.
光纤通信 微波 非线性光信号处理 光子晶体光纤 060.2330 Fiber optics communications 350.4010 Microwaves 070.4340 Nonlinear optical signal processing 060.5295 Photonic crystal fibers Chinese Optics Letters
2009, 7(11): 990
Author Affiliations
Abstract
1 Accelink Technologies Co., Ltd, Wuhan 430074, China
2 School of Information Science and Engineering, Shandong University, Ji’nan 250100, China
3 Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
A new dynamic model is developed for simulating the widely tunable grating assisted codirectional coupler with rear sampled grating reflector (GCSR) lasers. The gain section of the device is calculated in timedomain using traveling-wave method, while the transmission spectrum of the coupler and the reflection spectrum of the reflector are firstly simulated in frequency-domain, and then transformed into time-domain via digital filter approach. Both static and dynamic performances based on this model agree well with the published results. Compared with previous works, this new model is more efficient and applicable, especially in the dynamic simulation.
GCSR半导体激光器 行波法 传输矩阵法 数字滤波器法 250.3140 Integrated optoelectronic circuits 250.5300 Photonic integrated circuits 250.5960 Semiconductor lasers Chinese Optics Letters
2009, 7(10): 960
