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 (TNList), Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
By optimizing the gain configuration and length of the loop, a 90-tone optical frequency comb (OFC) is successfully generated based on recirculating frequency shifter structure. The peak-to-peak power fluctuation of the 90-tone OFC is 4.26 dB and the tone-to-noise ratio is higher than 19.17 dB. To further analyze the noise accumulation feature of the tones when travelling around the loop, linewidth of the tones is measured by delayed self-heterodyne interferometer structure. The result shows the linewidth of the tones deteriorates little during the recirculating process, indicating that the generated OFC is an ideal multi-wavelength source for high-speed communication systems.
060.0060 Fiber optics and optical communications 060.2380 Fiber optics sources and detectors 060.4510 Optical communications Chinese Optics Letters
2014, 12(10): 100601
Author Affiliations
Abstract
1 Tsinghua National Laboratory for Information Science and Technology (TNList), Beijing 100084, China
2 Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
A serial line scan microscopic imaging system with 1 GHz scan rate is proposed and demonstrated. This method is based on optical time-stretch in dispersive fiber to realize superfast scan imaging. Furthermore, a wavelength division technique is utilized to overcome the trade-off between high frame rate and spatial resolution caused by dispersion-induced pulse overlap. Every single frame is carved into two channels by optical filters and is detected in different wavelength bands separately. Then, both channels are combined to reconstruct the whole frame. By this method, an imaging system with spatial resolution of 28 μm at line scan rate of 1 GHz with chromatic dispersion of 1377 ps∕nm is realized. It has the potential to capture fast, nonrepetitive transient phenomena with a timescale of less than one nanosecond.
Imaging systems Microscopy Fiber optics components Photonics Research
2014, 2(4): 04000B31
Author Affiliations
Abstract
Tsinghua National Laboratory for Information Science and Technology (TNList), Department of Electrical Engineering, Tsinghua University, Beijing, 100084, China
A photonic-assisted radio frequency (RF) down-converter integrating with the optoelectronic oscillator (OEO)-based high quality local oscillator (LO) has been proposed and experimentally demonstrated. The LO and the RF input signal are mixed at the same phase modulator and photo-detector (PD) of the OEO-loop without any additional modulator or PD. The working bandwidth of the proposed RF down-converter is nearly from 2.5 to 10 GHz. The performance of the proposed down-converter is presented and the spurious frequency dynamic range at frequency of 5.5 GHz with the LO at 6.138 GHz is measured to be 98.4 dB–Hz2∕3. The influences that the frequency range and power of the RF input signal bring to the system are discussed as well.
Fiber optics and optical communications Radio frequency photonics Oscillators Photonics Research
2014, 2(4): 040000B1
Author Affiliations
Abstract
An optimal power distribution analysis for an all-optical sampling orthagonal frequency division multiplexing (OFDM) scheme with multiple modulation formats including differential phase shift keyed (DPSK), differential quadrature phase shift keyed (DQPSK), and non-return-to-zero (NRZ) is proposed. The noise tolerances of different modulation formats are analyzed, and the optimal input power ratio between phase and intensity modulation formats for the best overall receiving performance is investigated under unchanged total input power. Moreover, this scheme can seamlessly coexist with the traditional WDM channel.
060.4510 Optical communications 060.4230 Multiplexing 060.4080 Modulation Chinese Optics Letters
2013, 11(10): 100604
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
1 Tsinghua National Laboratory for Information Science and Technology (TNList), Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
2 The Photonic Systems Research Laboratory, Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China
Frontiers of Optoelectronics
2013, 6(1): 25
Author Affiliations
Abstract
An experimental demonstration of an all-optical sampling orthogonal frequency division multiplexing (AOS-OFDM) transmission system with inline chromatic dispersion (CD) compensation is carried out to test the nonlinear influence. With five subcarriers non-return-to-zero (NRZ) modulated, the total bit rate is 50 Gb/s without polarization multiplexing. The receiver end is highly simplified with direct detection using optical Fourier transform filter. After transmission in 160-km standard single-mode fiber (SSMF) link with 130-ps/nm residual CD, an optimum input optical power for the system performance is achieved.
060.4510 Optical communications 060.4230 Multiplexing 060.3735 Fiber Bragg gratings 060.4370 Nonlinear optics, fibers Chinese Optics Letters
2012, 10(2): 020601
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
