河南科技大学农业装备工程学院, 河南 洛阳 471003
双孢蘑菇质地柔嫩、 营养丰富, 具有很好的降血压、 降血脂、 消炎护肝等多种保健价值, 其新鲜度是反映内外部品质的重要指标之一。 目前双孢蘑菇新鲜度鉴别大多依据其外观品质变化(褐变), 缺乏精准的量化评价指标与方法, 因此提出了以贮藏天数为新鲜度检测的量化指标, 并利用近红外光谱技术对双孢蘑菇新鲜度进行检测分析。 依据存储天数不同, 将双孢蘑菇样本分为1~5组, 每组40个样本, 依次采集每组双孢蘑菇的近红外光谱数据。 针对采集的原始光谱数据, 首先选用卷积平滑滤波(SG)与多元散射校正(MSC)消除原始光谱噪声、 基线平移以及光散射的影响, 并选取399.81~999.81 nm的光谱波段作为数据处理范围; 然后分别使用主成分分析(PCA)和连续投影算法(SPA)进行光谱降维和特征波长选择, 继而建立极限学习机(ELM)分类模型; 同时考虑到ELM模型中初始值对分类准确率影响较大, 分别选用粒子群优化算法(PSO)、 海鸥优化算法(SOA)对ELM中初始权值及阈值进行寻优, 形成PSO-ELM, SOA-ELM优化组合分类模型; 最后分别将全光谱、 提取主成分以及所选的特征波长{556.87, 445.51, 481.15, 885.10, 802.25, 720.90, 861.34, 909.79, 924.44, 873.17 nm}输入到分类模型中, 建立不同输入、 不同分类模型的双孢菇新鲜度检测模型。 最终试验结果表明, 当ELM为分类模型, 以全光谱、 主成分以及特征波长为输入时的预测精度分别为75%, 95%, 88%; 以SPA优选特征波长作为输入的PSO-ELM、 SOA-ELM分类模型训练集精度为96.25%, 93.25%, 预测集精度为92.5%, 94%。 可知, SPA波长选择算法可以有效降低光谱信息中存在的冗余信息, 加快建模效率, 同时海鸥优化算法能较好的优化ELM分类模型的初始参数, 分类精度较ELM模型提高了6.8%, 同时不产生过拟合现象。 因此, 利用光谱特征可以快速、 准确无损的识别双孢蘑菇的新鲜度, 研究结果为便携式双孢蘑菇新鲜度快速无损检测设备的开发提供了理论依据。
近红外光谱 双孢蘑菇 新鲜度 极限学习机 Near infrared Agaricus bisporus Freshness Extreme Learning Machine SOA-ELM SOA-ELM 光谱学与光谱分析
2021, 41(12): 3740
1 武汉理工大学信息工程学院, 武汉 430070
2 武汉理工大学光纤传感技术国家工程实验室, 武汉 430070
针对现有光学相干层析成像(OCT)中所用扫频激光光源能量较低这一技术瓶颈, 研究了一种基于SOA级联的傅里叶域锁模(FDML)扫频光源, 利用中心波长为1310nm的半导体光放大器(SOA)搭建了双环形腔扫频光源。对系统中两只SOA的输出特性和基于SOA级联的双环扫频光源的光谱输出特性进行了研究。结果表明, 在SOA工作电流为280mA下, 该扫频光源光功率达28mW, 扫频速度达81.3kHz, 扫频范围超过90nm, 瞬时线宽小于0.03nm。
SOA级联 傅里叶域锁模 扫频光源 光功率 cascading SOA Fourier domain mode-lock swept laser source optical power
Author Affiliations
Abstract
Key Laboratory of Optical Fiber Sensing & Communications (Ministry of Education), School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China
An all-optical ultrawideband monocycle generator based on wavelength conversion in a semiconductor optical amplifier (SOA) and optical tunable delay in an optical delay line (ODL) is proposed and simulated. The system achieves optically switchable in pulse polarity and tunable in both the pulsewidth and radio frequency (RF) spectrum.
Microwave photonics ultrawideband (UWB) tunable switchable semiconductor optical amplifier (SOA) tunable time delay Photonic Sensors
2017, 7(1): 66
上海理工大学 教育部微创医疗器械工程中心, 上海 200093
提出了一种利用声光调谐方法进行滤波的扫频光源来提高它的输出稳定性。阐述了实现光源稳定输出的原理和方法, 研究和分析了光源的相关参数。该系统采用声光调谐的方法代替机械滤波的方式。在一个环形腔内, 使用半导体光放大器(SOA)作为增益介质, 声光可调谐滤波器(AOTF)作为波长选择元件, 利用声光调谐的原理对腔内的光进行选频滤波。在280 mA的注入电流下, 得到了1 294~1 368 nm的扫频光源, 其中心波长为1 328 nm, 半高全宽为51 nm, 扫频速度为3 731 Hz, 环形腔内直接输出的光功率为1.14 mW。由于AOTF是电控制元件, 波长的调谐不需要机械移动部件, 故提高了系统的稳定性, 输出光谱的重复性也很好。实验显示: 通过这种方法获得的扫频光源输出稳定, 基本满足扫频相干层析成像系统对扫频光源工艺参数的要求。
扫频光源 声光可调谐滤波器 半导体光放大器 无机械移动 稳定输出 swept-source Acousto-optic Tunable Filter(AOTF) Semiconductor Optical Amplifier(SOA) non-mechanical movement stable output 光学 精密工程
2016, 24(11): 2658
Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information,Huazhong University of Science and Technology, Wuhan 430074, China
In this paper, we demonstrated a novel physical mechanism based on the well-barrier hole burning enhancement in a quantum well (QW) semiconductor optical amplifier (SOA) to improve the operation performance. To completely characterize the physical mechanism, a complicated theoretical model by combining QW band structure calculation with SOA’s dynamic model was constructed, in which the carrier transport, interband effects and intraband effects were all taken into account. The simulated results showed optimizing the thickness of the separate confinement heterostructure (SCH) layer can effectively enhance the well-barrier hole burning, further enhance the nonlinear effects in SOA and reduce the carrier recovery time. At the optimal thickness, the SCH layer can store enough carrier numbers, and simultaneously the stored carriers can also be fast and effectively injected into the QWs.
nonlinear optics nonlinear optics optical signal processing optical signal processing semiconductor optical amplifier (SOA) semiconductor optical amplifier (SOA) Frontiers of Optoelectronics
2016, 9(3): 353
State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
All-optical high-speed turbo-switches can effectively increase the switching speed using cascaded semiconductor optical amplifiers (SOAs). The overall recovery time or the bandwidth of turbo-switch was numerically analyzed with time-domain and frequencydomain SOA models. The turbo-switch was explored from the fundamental carrier dynamics in SOAs for the purpose of further increasing its operation speed. An integrated turbo-switch was also been proposed and demonstrated, where a phase adjustable Mach-Zehnder interferometer (MZI) was applied as an optical band-pass filter between SOAs. Wavelength conversion was first demonstrated at 84.8 Gbit/s using the integrated turbo-switch.
semiconductor optical amplifier (SOA) semiconductor optical amplifier (SOA) alloptical signal processing alloptical signal processing high-speed switches high-speed switches semiconductor integration semiconductor integration Frontiers of Optoelectronics
2016, 9(3): 346
1 Optical Communications Research Group, Department of Electronic and Computer Engineering, University of Limerick, Limerick, Ireland
2 Lab-STICC, UMR CNRS 6285, école Nationale d’Ingénieurs de Brest CS 73862, 29238 Brest Cedex 3, France
3 Alcatel Thales III–V Laboratory, Route Departementale, 128, 91767 Palaiseau, France
Differential quadrature phase shift keying (DQPSK) modulation is attractive in high-speed optical communications because of its resistance to fiber nonlinearities and more efficient use of fiber bandwidth compared to conventional intensity modulation schemes. Because of its wavelength conversion ability and phase preservation, semiconductor optical amplifier (SOA) fourwave mixing (FWM) has attracted much attention. We experimentally study wavelength conversion of 40 Gbit/s (20 Gbaud) non-return-to-zero (NRZ)-DQPSK data using FWM in a quantum dash SOAwith 20 dB gain and 5 dBm output saturation power. Q factor improvement and eye diagram reshaping is shown for up to 3 nm pump-probe detuning and is superior to that reported for a higher gain bulk SOA.
differential quadrature phase shift keying (DQPSK) differential quadrature phase shift keying (DQPSK) phase modulation phase modulation quantum-dash quantum-dash semiconductor optical amplifier (SOA) semiconductor optical amplifier (SOA) four-wave mixing (FWM) four-wave mixing (FWM) wavelength conversion wavelength conversion Frontiers of Optoelectronics
2016, 9(3): 341
Author Affiliations
Abstract
1 National Engineering Laboratory for Fiber Optic Sensing Technology, Wuhan University of Technology, Wuhan, 430070, China
2 Key Laboratory of Ministry of Education for Fiber Optic Sensing Technology and Information Processing, Wuhan University of Technology, 430070, China
A time division multiplexing of 106 weak fibers Bragg gratings (FBGs) based on a ring resonant-cavity is demonstrated. A semiconductor optical amplifier is connected in the cavity to function as an amplifier as well as a switch. The 106 weak FBGs are written along a SMF-28 fiber in serial with peak reflectivity of about -30 dB and equal separations of 5 m. The crosstalk and spectral distortion are investigated through both theoretical analysis and experiments.
Fiber Bragg grating (FBG) semiconductor optical amplifier (SOA) time-division multiplexing (TDM) Photonic Sensors
2016, 6(2): 132
