波分复用光纤通信中的光学计量学

1 引言为响应光纤技术的快速发展，美国国家标准技术研究院（NIST）的光电子学分部已研制成许多技术和标准，以支持用于波分复用光纤通信系统中的光学元件和子系统的测量。现行项目包括波长校正传递标准的研制和光纤及元件的光谱响应、色散和偏振关系的准确测量。宽带光纤通信系统的快速增长已大大增加对光纤及元件的光谱、偏振和色散性质精确测量的需求。波分复用（WDM）利用许多波长通道来增加带宽。在1540~1560 nm波长范围里，大多数系统采用50 GHz(0.4 nm)或100 GHz (0.8 nm)的通道间隔，但将来能实施更窄的通道间隔。系统也将用于…     

四种表示波分复用元件特征的测量方法

根据光纤系统的波长范围,精度要求和对时间的考虑来选择最好的测量方法。波分复用可以极大地提高光纤系统的容量。目前,安装的系统高达40条通道,而96条通道的系统已经研制了。这样增长的结果导致了通道间隔从200 GHz到50 GHz。它增加了位于系统中心的多路分配器的复杂性,并增加了对测量装置的性能要求。     

CMOS兼容的中红外多通道光子晶体传感器（英文）

提出了一种基于光子晶体的二维多通道光学化学传感器。该器件由中心波长为3.3μm的四个腔组成,各通道工作波长间隔为10 nm。该传感器采用800 nm厚的绝缘体上硅材料,可利用标准CMOS技术加工。通过三维时差有限差分法对微腔结构的光学特性进行模拟。每个通道的传输效率为39%,通道之间的传输效率不一致性小于0.25dB。该传感器的功能为检测四氯化碳和苯溶液浓度,其灵敏度为209.2 nm/RIU。     

WA-7000DWDM高精度多路波长计

密集型波分复用通信(DWDM)技术在普通光纤通信系统中,可以提供无与伦比的宽带波段特性,并以极快的速度在发展.目前,通道间隔为100 GHz(约0.8nm)的DWDM系统已达到实用化水平.某生产DWDM系统的公司宣布已研制了通道间隔为50 GHz的系统.测量绝对波长的各种主要参数用的实验装置非常重要,它是准确评价DWDM系统特性的关键装置.     

CMOS兼容的中红外多通道光子晶体传感器

我们提出了一种基于光子晶体的二维多通道光学化学传感器。该器件由中心波长为3.3 μm的四个腔组成,各通道工作波长间隔为10 nm。该传感器采用800 nm厚的绝缘体上硅材料,可利用标准CMOS技术加工。我们通过三维时差有限差分法对微腔结构的光学特性进行模拟。每个通道的传输效率为39％,通道之间的传输效率不一致性小于0.25dB。该传感器的功能为检测四氯化碳和苯溶液浓度,其灵敏度为209.2 nm/RIU。     

原子层热电堆材料的激光感生热电电压

测量了La1-xSrxMnO3(LSMO),La1-xPbxMnO3(LPMO)和La1-xSrxCoO3(LSCO)三种薄膜在不同激光波长下的激光感生热电电压(LITV).利用脉冲激光沉积(PLD),在LaAlO3倾斜衬底上制备了钙钛矿结构的三种薄膜,并用电脑采集系统和锁相斩波系统对激光感生热电电压信号进行测量。发现不同波长下信号的灵敏度和响应时间各不相同,激光波长为532nm和632.8nm时LSMO灵敏度最大而LSCO最小,但响应时间恰好相反。波长为808nm时LPMO灵敏度最好。     

星载测风激光雷达系统鉴频器性能模拟比较

模拟了基于355nm波长双边缘FP（Fabry-Perot）鉴频器和基于532nm波长碘分子鉴频器的星载测风激光雷达系统性能。进行的比较和分析主要包括激光出射光子数、大气后向散射强度、探测器、鉴频器及测风灵敏度等。给出了星载平台系统接收后向散射信号的信噪比和测风误差,以评估两种激光雷达系统的性能。结果表明,在距地面0-5km高度范围,532nm碘分子鉴频器系统测风误差低于355nm 双边缘FP系统,而对于距地面5km以上大气范围,FP系统风速误差比碘分子鉴频器系统低25%。     

相位调制的瞬时微波频率测量的Optisystem仿真研究

通过对基于相位调制的瞬时微波频率测量系统结构的分析,在Optisystem仿真软件平台上进行了详细的结构仿真和器件参数设定值分析。通过根据输入的不同载波波长得到的分段测量结果值,在总测量频程6～18GHz范围内,最低精度可达到0.1GHz,使得到的测量频率值相对于特定频段更具有代表性。通过检测输出端功率比,求得待测频率,实现了测量频程在6～11GHz时,测量精度总体约为0.5GHz;测量频程在11～15GHz时,测量精度总体约为0.2GHz;测量频程在15～18GHz时,测量精度总体约为0.1GHz。     

时分副载波半导体DFB激光多路波长锁定器

我们研制成功8路时分副载波半导体DFB激光器波长锁定器.用1kHz正弦时分电信号,分别对8个1.55μm波段的DFB激光器进行1％的幅度调制,每个DFB激光2％的光信号分成两路,一路通过自由光谱区为100 GHz的F-P标准具,另一路作参考光,两路的光电差分信号反馈控制DFB激光器的温度,使每个DFB激光器锁定在各自所需的波长上.测试结果表明波长锁定的激光频率间隔100 GHz,波长锁定精度优于±2.5GHz。该方法同样适用于50GHz频率间隔和更多路的波长锁定.本文着重介绍该锁定器的光电信号处理和控制方法.     

F-P标准具间距高精度测量

提出一种通过测量F-P标准具透射峰移动个数与F-P标准具入射角度改变的对应关系,从而求得F-P标准具间距的高精度测量方法。当角度测量精度为30″,光谱仪精度为2 GHz时,该方法测量F-P标准具间距的相对误差为4×10~(-4).     

激光线性扫频法快速标定法布里-珀罗标准具参数

法布里-珀罗标准具是一种精密的光学仪器,其光谱窄、精细度高,广泛应用于精细距离的测定、信号的检测分析等。标准具其自身参数的快速测量和准确标定成为诸多光学研究必不可少的步骤。针对法布里-珀罗标准具参数测量,设计快速标定实验方案,采用窄线宽(线宽1 kHz)激光光源,数字示波器采用泰克DPO4104B(1 GHz,5 GS/s)进行采样存储,直接利用屏幕图像测试并计算标准具的主要参数指标。准确标定了所测法布里-珀罗标准具的自由谱宽、半高全宽、精细度、品质因数以及扫频常数,比较分析了两种不同测试方案所得到结果。为开展法布里-珀罗标准具参数的快速准确标定提供技术参考。     

Widely tunable chaotic fiber laser for WDM-PON detection

A widely tunable high precision chaotic fiber laser is proposed and experimentally demonstrated. A tunable fiber Bragg grating （TFBG） filter is used as a tuning element to determine the turning range from 1533 nm to 1558 nm with a linewidth of 0.5 nm at any wavelength. The wide tuning range is capable of supporting 32 wavelength-division mul- tiplexing （WDM） channels with 100 GHz channel spacing. All single wavelengths are found to be chaotic with 10 GHz bandwidth. The full width at half maximum （FWHM） of the chaotic correlation curve of the different wave- lengths is on a picosecond time scale, thereby offering millimeter spatial resolution in WDM detection.     

Tunable polymer optical add/drop filter for multiwavelength networks

We present a polymer optical add/drop filter with a channel cross-talk of -18.5 dB, a free spectral range of 12.8 nm and a channel spacing of 400 GHz (4 channels) as well as a tunable optical filter with a free spectral range of 50 nm. Both filter designs are based on a synthesis which provides the minimum number of filter stages for a given channel crosstalk and number of channels. Wavelength tunability over the entire free-spectral range (FSR) is demonstrated with applied heating powers of 500 mW. For the narrow bandwidth filter we used a fluorinated high temperature stable polymer as the waveguiding material, which has proven to exhibit losses as low as 0.25 dB/cm at a wavelength of 1.55 /spl mu/m.     

瑞利多普勒激光雷达F-P标准具的设计与校准分析

为了精确观测平流层风场,采用F-P标准具作为瑞利散射测风激光雷达多普勒频率检测的核心器件,对F-P标准具多普勒频率检测原理进行了理论分析,从分析最大设计高度时的测量误差着手,优化选取标准具透过率曲线参量;介绍了透过率曲线参量的校准过程和校准方法,分析了导致透过率曲线的半峰全宽增大的原因、透过率曲线校准精度对速度灵敏度及系统探测误差的影响;并通过实验对设计和校准结果进行了验证。结果表明,由于透过率曲线的半峰全宽增大,导致速度灵敏度下降了0.118%/（m·s-1）;40km高度处,在测量信噪比大于10的条件下,径向速度测量精度增大2m/s。     

Frequency tuning characteristics and WDM channel access of thesemiconductor three-branch Y3-lasers

We describe frequency tuning and channel access characteristics of the new, widely-tunable, multi-quantum-well three-branch Y3-lasers. The Y3-lasers are tuned discretely with two independent current controls: coarse tuning (5.5 nm, 680 GHz tuning steps) selects the desired optical frequency range, fine tuning selects the desired frequency channel (0.4 nm, 50 GHz channel spacing). For example, we demonstrate access to 50 channels over the ~31 nm free spectral range of the Y3-laser; 36 contiguous channels are accessed using three independent current controls. The coarse/fine “digital” tuning makes Y3-lasers very useful for wavelength-division-multiplexed (WDM) multi-channel optical communication systems     

168 channels /spl times/ 6 GHz from a multiwavelength mode-locked semiconductor laser

A gain-flattened multiwavelength mode-locked semiconductor laser generates 168 discrete wavelength channels at 6 GHz. Intracavity etalon filtering delineates the 0.12-nm-spaced channels while spatial filtering inside a spectrometer broadens the laser spectrum to 20 nm. Mode locking produces 85-ps pulses in each channel at 750 MHz. The pulse-repetition rate is multiplied to 6 GHz per channel via optical time-division multiplexing to yield an aggregate pulse rate of 1 THz.     

Evans双折射滤波器特性分析

为了从理论上对Evans滤波器的性质进行研究，利用Mueller矩阵和Stokes参量进行理论分析，得到了Evans双折射滤波器的透射比，自由光谱范围和通带半高宽的公式。分析结果表明自由光谱范围和通带半高宽随干涉级次的变大单调下降；自由光谱范围和通带半高宽随波长变长单调上升，并近似是线性关系。     

InP‐Based Polarization‐Insensitive Planar Waveguide Concave Grating Demultiplexer with Flattened Spectral Response

InP‐based planar waveguide 48‐channel concave grating demultiplexers with a channel spacing of 0.8 nm (100 GHz) are described and demonstrated. Polarization insensitivity and flattened spectral response are successfully achieved by the introduction of a polarization compensator and a two‐focus grating, respectively. The fabricated device shows a polarization‐dependent wavelength shift of less than 20 pm and a ?3 dB spectral width of about 0.55 nm (68.75 GHz) over all channels.     

Simulation analysis and implementation of spectral dispersion system based on virtually imaged phased array

Virtually imaged phased array (VIPA) has the advantages of insensitive to polarization, simple structure and high in spectral resolution. Compared with commonly used dispersive devices, such as diffraction gratings or Fabry-Pérot (FP) interferometers, VIPA is self-aligned and has high transmission efficiency. In this paper, the dispersion mechanism of the VIPA is introduced in detail, the influence of incident angle and VIPA thickness on the dispersion performance near 532 nm is calculated and analyzed with MATLAB. According to the calculated results, the selected VIPA device has a thickness of 6 mm and an incident angle of 4°. The spectral dispersion system, in combination with corresponding optical devices, is designed and simulated with ZEMAX, then the experimental system was built. The spectral dispersion system based on VIPA, at a central wavelength of 532 nm, has the free spectral range of 15.08 GHz and the spectral resolution of 0.87 GHz. The system designed in this paper can be applied to high-resolution spectral detection such as Brillouin scattering, Raman scattering, laser fluorescence, laser-induced plasma and so on.     

基于硅纳米线波导的16通道200GHz阵列波导光栅

设计了基于硅纳米线波导的16通道,通道间隔为200GHz的阵列波导光栅(AWG)。传输函数法模拟了器件传输谱,结果表明器件的通道间隔为1.6nm,通道间串扰为31dB。器件利用SOI材料,由193nm深紫外光刻工艺制备。光谱测试结果分析表明,通道串扰为5-8dB,中心通道损耗2.2dB,自由光谱区长度24.7nm,平均信道间隔1.475nm。详细分析了器件谱线畸变的原因。