D. Y. Zhang

China Academy of Engineering Physics, Peping, Beijing, China

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Publications (3)3.55 Total impact

  • Zh M Huang, C L Liu, J F Li, D Y Zhang
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    ABSTRACT: A phase controller for coherent beam combining (CBC) of fibre lasers has been designed and manufactured based on a stochastic parallel gradient descent (SPGD) algorithm and a field programmable gate array (FPGA). The theoretical analysis shows that the iteration rate is higher than 1.9 MHz, and the average compensation bandwidth of CBC for 5 or 20 channels is 50 kHz or 12.5 kHz, respectively. The tests show that the phase controller ensures reliable phase locking of lasers: When the phases of five lasers are locked by the improved control strategy with a variable gain, the energy encircled in the target is increased by 23 times than that in the single output, the phase control accuracy is better than λ/20, and the combining efficiency is 92%.
    Quantum Electronics 04/2014; 44(4):301. DOI:10.1070/QE2014v044n04ABEH015230 · 0.89 Impact Factor
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    ABSTRACT: A coherent combination model of fiber lasers has been established. The relative beam quality factor has been introduced and studied as a proper beam quality factor for the combined coherent beam. The disturbance of the phase shift, polarization degradation, distribution characteristic, the wave-front aberration and the tilt error has been numerically studied to investigate their effects on the beam quality. This model has been also used to analyze the control of beam steering. The results have shown that the impact of the phase shift on the combination is more serious than that caused by polarization degradation, and the coherence degradation caused by the phase grating is more severe than that caused by the phase shifter.
    Laser Physics 08/2012; 22(8). DOI:10.1134/S1054660X12080129 · 1.03 Impact Factor
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    ABSTRACT: In a laser coherent combination, the phase detection and control is the most critical. Using the beat frequency method, consistence of the phase in output beams can be ensured through real-time detection and correction for the phase change. Phase noises are controlled by a liquid crystal phase modulator. At the same time, the liquid crystal polarization controller is used to make the polarization state stable, which is good for the improvement of the combining efficiency. The wave length of the main oscillation laser is 532nm. The output power of laser can be adjusted continuously from 0 to 6W. The shifted frequency of the system is 40MHz. The accuracy for phase control is superior to λ/70RMS. In the process of closed-loop control, using the liquid crystal phase and polarization controller, a better signal phase correction of optical path has been achieved for the coherent combination of high power laser arrays.
    Applied Physics B 11/2010; 101(3):559-563. DOI:10.1007/s00340-010-4245-x · 1.63 Impact Factor