共查询到20条相似文献,搜索用时 31 毫秒
1.
A novel adaptive-fiber-optics-collimator (AFOC) compensating both piston-type and tip/tilt-type phase errors of output beam is introduced, and has been employed in experiments of coherent beam combination (CBC) of a delta distributed fiber array. Feedback control is realized using stochastic parallel gradient descent (SPGD) algorithm. Excellent CBC effect has been achieved when piston and tip/tilt errors among beamlets corrected. The necessity of wavefront tip/tilt control in CBC is verified. Experimental results exhibit great potential applications of this kind of AFOC in fiber amplifier arrays. 相似文献
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A new approach for the simultaneous coherent and spectral addition of a two-dimensional array of fiber lasers is presented. A combining efficiency of over 80% and a combined beam profile with M(2)=1.15 were experimentally obtained with an array of four fiber lasers. This approach can lead to significant upscaling in fiber laser additions. 相似文献
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Joyce Kilmer 《Fiber and Integrated Optics》2013,32(2):79-91
This paper introduces and analyzes revolutionary laser system architecture capable of dramatically reducing the complexity of laser systems while simultaneously increasing capability. The architecture includes three major subsystems. The first is a phased array of laser sources. In this article, we discuss diode-pumped fiber lasers as the elements of the phased array, although other waveguide lasers can also be considered. The second provides wavefront control and electronics beam steering, as described in an IEEE Proceedings article on “Optical Phased Array Technology” [1]. The third is subaperture receiver technology. Combining these three technologies into a new laser systems architecture results in a system that has graceful degradation, can steer to as wide an angle as individual optical phased array subapertures, and can be scaled to high power and large apertures through phasing of a number of subapertures. Diode-pumped fiber lasers are appealing as laser sources because they are electrically pumped, efficient, relatively simple, and scalable to significant power levels (over 100 Watts has been demonstrated from a single diode-pumped fiber laser) [2]. The fiber laser design also lends itself to integration into a phased array. Fiber lasers have been phased. Initial phasing demonstrations have been at low power and were conducted by taking a single source, dividing it into multiple fibers, then phasing them together. To develop this technology further we need to use independent fiber lasers or fiber amplifiers, seeded by a common source, and to increase laser power. As we increase laser power, we will have to learn to cope with nonlinearities in the laser amplifiers. Optical Phased Array technology has demonstrated steering over a 90-degree field of regard [4], although this approach used additional optical components. If we use straightforward optical phased array beam steering without additional optics we can steer with high efficiency to about one-third λ/d, where d is the smallest individually addressable element. The one-third factor depends on the efficiency threshold. For example, if we use 1.5 μm light, and 5 μm center-to-center spacing, we can steer with high efficiency to about ±6 degrees, or a field of regard of 12 degrees. Last, we need to develop a subaperture receive technology. This can be a pupil plane receiver, an image plane receiver, or some combination of the approaches. When we have matured each individual technology and combined them into new laser systems architectures, we will have the ability to build simpler and more capable laser systems. The vision for an integrated, phased array laser concept is to enable a new class of laser systems with significant advantages, including high-efficiency, all-electric laser source; all waveguide beam transport; wavefront control at the sub-aperture level (enabling wavefront compensation, conformal apertures, and wide-angle electronic beam steering); random access beam pointing over wide angles; multiple simultaneous beam generation and control; and graceful degradation. 相似文献
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选取不同路数和不同填充因子的合成光束模型,模拟并分析了倾斜相差对相干合成的影响.介绍了倾斜校正的关键器件--自适应光纤光源准直器.在主振荡功率放大器结构的光纤激光相干合成系统中,模拟了随机并行梯度下降(SPGD)算法校正七路激光阵列间时变倾斜相差的动态过程,分析了不同倾斜相差幅值和频率对校正能力的影响.实验表明,要提高相干合成的效果,必须校正倾斜相差;而SPGD算法校正倾斜相差的能力随着倾斜相差幅值和频率的增加而降低.文章为在实际大气环境中实现多路高功率光纤激光的相干合成提供了参考.
关键词:
光纤激光
相干合成
倾斜相位差
动态分析 相似文献
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Xingchun Chu Shanghong Zhao Lei Shi Shengbao Zhan Jie Xu Zhuoliang Wu 《Optics Communications》2008,281(15-16):4099-4102
Aiming at the problem that the channel number in spectral beam combining (SBC) of fiber lasers array is limited by the narrow spectral selectivity of grating, a new scheme based on cascaded volume Bragg gratings (VBG) is proposed to expand the channel number. A system cascaded by two VBGs is presented and analyzed. A formula used to accurately determine the angle of incidence of all the channels is derived using rigorous coupled-wave analysis (RCWA). The channel number can be multiplied with increasing the number of VBGs. Numerical results show that the system based on cascaded VBGs is a good SBC combiner that has the ability to combine a large number of channels. 相似文献
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采用波长1064 nm,功率为1 W的种子激光实现了两路光纤激光的相干合成,采用了两只保偏光纤准直器接收两路光干涉信号,与利用透镜直接把干涉信号会聚在探测器上相比,这种耦合方式得到的光干涉信号的条纹对比度更高。对相位噪声以及相位噪声的带宽进行了研究,结果表明,相位噪声由电信号串扰以及环境扰动产生。通过人为拨动光纤来增加相位噪声带宽,当相位噪声带宽增加时,相位控制精度下降。提出了提高相位控制精度的方法,实验获得了桶中功率为21.3%、斯特列尔比为79%、相位控制精度为0.008的相干合成效果。 相似文献
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Byoung Chang Lee 《Optics Communications》2011,284(19):4607-4610
We propose a high-speed remote fiber Bragg grating (FBG) sensor interrogation system based on a 1.3-μm cascaded Fourier-domain mode-locked (FDML) laser. It consists of multiple FBGs connected to an optical circulator in the laser cavity. The cascaded FDML laser with these multiple FBGs is operational when the scanning frequency of the fiber Fabry-Perot tunable filter matches the fundamental frequency of the laser cavity. Each FBG provides a separate laser cavity for the FDML laser. The scanning frequencies of each laser cavity are 30.5314, 31.5393, 32.7108, and 33.8023 kHz. Using the cascaded FDML laser, we measure the performance of the long-distance static strain FBG sensor interrogation system in both the time and spectral domains. The slope coefficients of the measured relative wavelength difference and the relative time delay from the static strain are found to be 0.95 pm/μstrain and 0.15 ns/μstrain, respectively. We also demonstrate the dynamic response of the interrogation system with 80-Hz modulation strain using the cascaded FDML laser. Thus, an FBG sensor interrogation system for high-speed and high-sensitivity long-distance monitoring systems can be realized using a cascaded FDML laser. 相似文献
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相干合成技术是实现高功率、高亮度光纤激光系统的重要技术途径.然而, 脉冲激光阵列中常常存在时域误差,这将影响脉冲激光的相干合成效果. 建立了脉冲激光存在时域误差时的相干合成理论模型,并在不同波形(方波、三角波、正弦波) 的脉冲激光存在时域误差时,对相干合成光束在远场的脉冲波形、峰值功率、 光强分布和桶中功率(PIB)等特性进行了数值计算和对比分析.计算结果表明: 方波脉冲激光相干合成光束的脉冲波形受时域误差影响严重,光强分布和PIB随着时域误差 的增大发生线性变化;三角波脉冲激光相干合成光束的脉冲波形和峰值功率受时域误差 影响严重,光强分布和PIB在时域误差较大时随着时域误差的增大发生较为剧烈的变化; 正弦波脉冲激光相干合成光束具有较好的输出特性,在两路正弦波脉冲激光相干合成中, 将两脉冲之间的时延控制在脉冲持续时间的10%以内,就能取得良好的合成效果. 相似文献
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A novel wavelength-switchable fiber laser source that can individually scan 14 required wavelengths within 40 ms, and its application in photonics true time delay beamforming is presented in this paper. The laser source is constructed using a unidirectional fiber ring cavity, a tunable fiber Fabry–Perot filter and two cascaded sampled fiber Bragg gratings with the wavelength spacing of 1.6 nm. A five-channel true-time-delay system using the proposed fiber laser source cooperating with a single-mode fiber and four chirped-grating-based is constructed and demonstrated for the application of phased array antenna beam steering. Continuous beam steering at the microwave frequency up to 20 GHz has been achieved. PACS 42.55.Wd; 42.81.Wg; 84.40.Ba 相似文献
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Pu Zhou Zilun Chen Xiaolin Wang Xiao Li Zejin Liu Xiaojun Xu Jing Hou Zongfu Jiang 《中国光学快报(英文版)》2008,6(7)
We demonstrate a scalable architecture for coherent combining of pulsed fiber lasers.A new method for generating synchronous pulsed fiber lasers by direct phase modulation is proposed and investigated.It is shown that phase modulated mutually coupled laser array can be a steady synchronous pulsed fiber laser source.The synchronous pulsed fiber lasers are coherently combined with an invariable phase difference of π in adjacent lasers.Neither active phase control nor polarization control is taken in our experiment. 相似文献
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Cheung EC Ho JG Goodno GD Rice RR Rothenberg J Thielen P Weber M Wickham M 《Optics letters》2008,33(4):354-356
A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers. 相似文献
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Switchable dual-wavelength Erbium-doped fiber ring laser with cascaded fiber Bragg gratings 总被引:1,自引:0,他引:1
Jae-Ho Han 《Optik》2010,121(24):2266-2268
We have experimentally shown wavelength mode switching in a dual-wavelength Erbium-doped single cavity fiber laser where the initial two wavelengths of 1 nm spacing are determined by the cascaded reflection type short-period fiber Bragg gratings having two different centre wavelengths of 1550.5 and 1551.5 nm. The lasing mode depends on the polarization in the ring cavity to migrate from one wavelength to another or operates in both modes in a polarization beam splitter output. To effectively control the polarization in the ring cavity, the polarization controllers were positioned before and after the polarization beam splitter. This method of wavelength switching provides a simple way of mode tuning in dual-wavelength fiber lasers. 相似文献
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We describe a newly developed combustion diagnostic for the simultaneous planar imaging of soot structure and velocity fields
in a highly sooting, lifted turbulent jet flame at 3000 frames per second, or two orders of magnitude faster than “conventional”
laser imaging systems. This diagnostic uses short pulse duration (8 ns), frequency-doubled, diode-pumped solid state (DPSS)
lasers to excite laser-induced incandescence (LII) at 3 kHz, which is then imaged onto a high framerate CMOS camera. A second
(dual-cavity) DPSS laser and CMOS camera form the basis of a particle image velocity (PIV) system used to acquire 2-component
velocity field in the flame. The LII response curve (measured in a laminar propane diffusion flame) is presented and the combined
diagnostics then applied in a heavily sooting lifted turbulent jet flame. The potential challenges and rewards of application
of this combined imaging technique at high speeds are discussed. 相似文献