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31.
在主动相位控制相干合成中,常用的光纤激光主动相位控制方法主要有外差法、多抖动法和随机并行梯度下降算法等. 基于多抖动法和外差法的原理,提出了一种新型的基于相位调制-解调的相位检测与控制方法. 该方法利用周期信号对参考光进行相位调制,将调制后的参考光与待检测信号光进行相干检测,通过对相干光强信号和相位调制信号的融合处理,实现相位噪声的检测和控制. 对该方法进行了数值模拟和实验研究. 实验结果表明,对于频率为2 kHz,噪声范围为[0,2π)的正弦噪声,相位检测精度优于λ/50,控制精度可达
关键词:
光纤激光
相干合成
相位噪声检测
调制-解调 相似文献
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By means of numerical simulations, we analyze the scintillation characterization for multiple incoherent uplink Gaussian beams under weak fluctuations cases. Because truly independent beams are difficult to create, we present a more general but approximate model for the multiple of beams traveling through partially correlated paths. This model compares with wave-optics simulations and highlights the reduced correlation coefficient as the beam separation is increased. The scintillation index of three and six incoherent uplink Gaussian beams is also induced. The result shows that the scintillation index decreases with the increase of beams amount and beam separation. When the beams amount and strength of atmospheric turbulence are fixed, the reduction of scintillation index is affected by the ratio of beams separation and the Fried length. The corresponding physical mechanisms for the results are discussed. 相似文献
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Coherent beam combining master oscillator-power of hybrid phase control in amplifier configuration 下载免费PDF全文
A novel scalable architecture for coherent beam combining with hybrid phase control involving passive phasing and active phasing in master oscillator-power amplifier configuration is presented. Wide-linewidth mutually injected passive phasing fibre laser arrays serve as master oscillators for the power amplifiers, and the active phasing using stochastic parallel gradient descent algorithm is induced. Wide-linewidth seed laser can suppress the stimulated Brillouin scattering effectively and improve the output power of the fibre laser amplifier, while hybrid phase control provides a robust way for in-phase mode coherent beam combining simultaneously. Experiment is performed by active phasing fibre laser amplifiers with passive phasing fibre ring laser array seed lasers. Power encircled in the main-lobe increases1.57 times and long-exposure fringe contrast is obtained to be 78% when the system evolves from passive phasing to hybrid phasing. 相似文献
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Coherent Beam Combining of Three Watt-Level Fiber Amplifiers Using a DSP-Based Stochastic Parallel Gradient Descent Algorithm 下载免费PDF全文
We present an experimental study on coherent beam combining of three watt-level fiber amplifiers using a stochas- tic parallel gradient descent (SPGD) algorithm. Phase controlling is performed by running the SPGD algorithm on a digital-signal-processor (DSP) chip with a voltage updating rate of 16500 times per second. Energy encircled in the target pinhole is 2.62 times more than that in an open loop. The combining efficiency is as high as 87%. 相似文献
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We demonstrate coherent beam combining of two
tiled-aperture single-frequency fibre amplifiers with a total output
power of 29.65~W by using the multi-dithering technique. The two laser
beams are packaged closely by using free-space mirrors side by side
into a tiled-aperture with a near-field fill factor of 62\%.
Active phase control of the amplifier is performed on commercially
available digital lock-in amplifiers. Experimental results show that
the power contained in the main-lobe in closed-loop is 1.72 times greater
than that in open-loop, which is 86\% for the ideal case. The
fringe contrast of the far-field fringe pattern is as high as 80\%
when the system is in closed-loop. The beam quality of the combined beam
is computed to be BQ = 1.48. The whole system in closed-loop performs
well in a long-time observation. 相似文献
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