共查询到20条相似文献,搜索用时 15 毫秒
1.
Hui-Zhen Li Xiang-wen Chen Cheng-tian Xue 《International Journal of Infrared and Millimeter Waves》1992,13(6):895-907
This paper describes an algorithm which can determine a neighborhood of the global optimum of an objective function and an estimate of the global optimum.This method wasemployed to determine global optimum of the fundamental mode power, the fractional power of the fundamental mode and the combining efficiency. Given this information, a local optimization procedure can be employed to local the global optimum.Work supported by natural science fund of China. 相似文献
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We report 2 x 2 and 4 x 4 multimode air-clad holey fiber couplers fabricated by a novel fusion and tapering technique. The devices showed excellent port-to-port coupling uniformity over a wide spectral range of 800-1650 nm. The 4 x 4 coupler showed a low insertion loss of 9.9 dB and excess loss of 3.9 dB at 1310 nm. Because of its unique air cladding and the high numerical aperture of the holey fiber structure, the device showed strong potential in high-power applications. 相似文献
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与传统的端发射半导体激光器相比,垂直腔面发射半导体激光器(VCSEL)具有可单模输出,光束对称性好,可被高度聚焦,进入光纤的耦合效率极高和有利于大规模二维列阵等优 点.为了得到高功率的激光输出,除了要增大VCSEL的发射面积之外,关键的是要选择适 当的量子阱层数、有源区电流密度的均匀分布和良好的热管理等.本文详细研究和分析了高功率VCSEL有源区量子阱层数,有源区直径,材料的热导和电阻,电极间距等对VCSEL 器件性能的影响.通过优化参数,进行最佳设计,研制出了980 nm In0.2Ga0.8As/Ga
关键词:
垂直腔面发射激光器(VCSEL)
量子阱
高功率 相似文献
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We propose a beam cleanup setup to convert a multimode beam into a single-mode beam by use of the Brillouin effect in a multimode gradient-index (GI) fiber. Phase conjugation and beam cleanup regimes in highly multimode fibers are discussed, and the self-aligned GI fiber Brillouin cavity is presented. We report a preliminary conversion from an M2=6.5 beam into an M2=1.3 beam with 31% efficiency. 相似文献
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A secure communication method for a high-power information signal based on chaotic masking 总被引:3,自引:0,他引:3 下载免费PDF全文
In this paper,we present a secure communication method for a high-power information signal based on chaotic masking.In the transmitter,an adaptive controller is adopted to pick up the change of the information signal ,and to inject the controller‘s error into the transmitting system.At the same time,the information is directly added to the chaotic signal in transmission to drive the receiving system.In the receiver,another adaptive controller is used to maintain chaotic synchronization of the transmitting and receiving systems and to recover the information signal.Since the synchronization error is independent from the information signal,the power of the information signal can be equivalent to that of the chaotic signal,and the frequency of the information signal can be set within the range of the principal frequencies of the chaotic signal,The results of theoretical analysis and numerical simulation show that the presented method not only enhances the degree of security of low-dimensional chaotic systems but also significantly improves the signal-to-noise ratio at the receiving end. 相似文献
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Hui-Zhen Li Xiang-Wen Chen 《International Journal of Infrared and Millimeter Waves》1997,18(10):1943-1956
This paper describes an algorithm which can determine the global optima of the power combiner of solid-state millimeter wave
resonator. The global optimization mehtod can determine a neighborhood of the global optima of an objective function and an
estimation of the global optima. In this paper the objective function as follow: In the quasi-optical resonator, the objective
function are the fundamental mode power, the fractional power of fundamental mode and the combining dfficiecy were done the
objective functiona respectively, to calculate the global optima respectively.
In the power combiner of solid-state millimeter wave source in rectangular waveguide cavity. the performance parameter are
presentes by combining efficiency, tuning range, frequency drift, and FM noise were done the objective functions respectively.
And to calculate the global optima respectively. 相似文献
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Lizhi Dong Wenjin Liu Ping Yang Bing Xu Xiang Lei Yu Ning Hu Yan 《Optics Communications》2011,284(7):2003-2006
Misalignment of a laser cavity would result in the displacement of beam location on the cavity mirrors. We present a simple method for automatic cavity alignment of a solid-state laser through detecting the location of the laser beam on the rear mirror, with which neither external alignment beams nor modifications to the cavity are required. The rear mirror of the laser cavity is replaced by a tip/tilt mirror to compensate for the misalignment. Experiments show that this method could effectively correct the misalignment of the laser cavity and restore the output power to almost the original value when the resonator is well aligned. 相似文献
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Dual-wavelength bandwidth-narrowed output of a high-power diode laser using a simple external cavity
Using an external cavity consisting of an etalon and a mirror, dual-wavelength operation of a high-power broad-area multi-stripe diode laser is achieved. The reflection of the etalon is used as the output beam of the system. The free-running bandwidth of the laser diode is about 2.0 nm. At dual-wavelength operation, the bandwidth of each wavelength component is narrowed to about 0.07 nm, while the space between them is 1.65 nm, determined by the FSR of the etalon. We obtain an available dual-wavelength output power of 2.0 W at the drive current of 6.5 A. The power ratio of the components at two different wavelengths can be changed by changing the temperature of the diode laser. To tune the wavelength of the dual-wavelength output, the temperature of the laser diode and the tilt angle of the etalon are changed simultaneously PACS 42.55.Px; 42.60.Fc; 42.60.Da 相似文献
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Z. Zhang G. Pauliat J. J. Lim P. J. Bream N. Dubreuil A. J. Kent E. C. Larkins S. Sujecki 《Optical and Quantum Electronics》2008,40(14-15):1117-1121
A self-consistent model of a self-organizing external cavity high power laser is presented. The model consists of a photorefractive crystal model, which relies on the plane wave approximation, and of a spectral model of the tapered laser amplifier. The results show that the laser can operate in a single longitudinal mode. 相似文献
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Gianluca Geloni Evgeni Saldin Evgeni Schneidmiller Mikhail Yurkov 《Optics Communications》2008,281(14):3762-3770
We propose a technique for timing an X-ray free-electron laser (XFEL) to a high-power conventional laser with femtosecond accuracy, yielding the relative jitter between pump and X-ray probe, and allowing sorting of experimental results over a certain time window. The same electron bunch is used to produce both an XFEL pulse and an ultrashort optical pulse by means of an optical radiator downstream of the X-ray undulator. Being produced by the same electron bunch, these pulses are perfectly synchronized. Cross-correlation techniques will allow to determine relative jitter between the optical pulse (and, thus, the XFEL pulse) and a pulse from an external pump-laser. Technical realization of the proposed timing scheme uses an optical-replica synthesizer setup to be installed after the final bunch-compression stage of the XFEL for electron bunch diagnostics purposes. A number of critical issues are quantitatively analyzed. 相似文献
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Yuanshen Huang Ziren PeiRuijin Hong Baicheng LiDawei Zhang Banglian XuZhengji Ni Songlin Zhuang 《Optik》2014
The so-called non-approximate method was adopted to design two-mirror three-reflection concentric Offner configuration for an dispersive spectrometer, which was using geometry and ray tracing method to derive the deviation between the arbitrary ray's image point and the principal ray's image point, the system aberration was evaluated based on this deviation, then each parameter was optimized and designed to meet the using conditions by computer software. The optimal object's position with minimal aberration, which also is known as the optimal imaging annular field, could be found in a different condition. Moreover, it presented that the ratio of the radius of convex grating to the radius of concave mirror ought to be close to 0.5∼0.6, the ratio r/R changed slightly with different wavelengths, but the bigger the wavelength was, the larger the ratio r/R would be. 相似文献
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为提升在中国原子能科学研究院的100 MeV质子回旋加速器上进行多能点质子单粒子效应实验的效率,针对该加速器提供的100 MeV质子设计了一种二进制降能器.降能器包括6片铝降能片,厚度分别为0.5,1,2,4,8,16,32 mm,即后一片厚度均为前一片的2倍.提出相对厚度的概念,此概念也可用来表示产生的质子能点的次序以及降能器的状态或操作.降能器产生的9.69 MeV以上的61个质子能点间隔在0.84—4.09 MeV之间,且能量岐离均在10%以下,散射角半高宽均在45 mrad以下,基本可满足质子单粒子效应实验的要求.对加速器直接提供的质子的能量精度对降能器产生的质子能点的影响进行分析,发现经降能器产生的质子能量越低,其影响也就越大.此外,降能器对加速器直接能够提供的70—100 MeV能区的质子也是适用的,且可通过增加降能片数量的方式来获得更加连续化的质子能点.本文提出的降能器设计方法简单有效,具有较强的借鉴价值. 相似文献
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《Optics Communications》2003,215(1-3):159-162
We report on a diode-pumped cw Nd:YAG laser operating at 946 nm with a maximum output power of 3.3 W and a slope efficiency of 22% with respect to the incident pump power of 17.5 W. Intracavity frequency doubling with nonlinear crystal LBO yielded a single-ended blue output power of 590 mW with optical conversion efficiency of 3.4%. A very simple, compact three-element cavity of 35 mm long was used. The power fluctuation of the blue laser was 4.3% (rms) at output power level of 400 mW. Transverse mode hopping was observed at higher output power. 相似文献
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光电色度计校正滤色器的一种设计方法 总被引:4,自引:0,他引:4
介绍了光电色度计的测色原理,给出了依卢瑟条件设计校正滤色器计算光谱透射比的基本计算式,以滤色片厚度为自变量采用总误差面积最小,误差平方和最小,色差最小三种评价函数对滤色器进行优化设计,最后得到较为满意的结果。 相似文献
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Fatih Özkaynak 《Physics letters. A》2010,374(36):3733-3738
It is important to design cryptographically strong S-Boxes in order to design secure systems. In this study, a strong, chaos-based S-Box design is proposed. Continuous-time Lorenz system is chosen as the chaotic system. Proposed methodology is analyzed and tested for the following criteria: Bijective property, nonlinearity, strict avalanche criterion, output bits independence criterion and equiprobable input/output XOR distribution. The results of the analysis show that the proposed cryptosystem is a highly reliable system suitable for secure communication. 相似文献