Fig. 1. Structure diagram of adaptive optical fiber coupling system

Fig. 2. Measurement of non-common optical path aberration by reverse transmission calibration algorithm

Fig. 3. Block diagram of adaptive optical closed-loop control

Fig. 4. Adaptive optical system with non-common optical path aberrations. (a) Peak-to-valley (PV) value and root mean square (RMS) value of uncorrected and closed-loop wavefronts; (b) closed-loop coupling efficiency

Fig. 5. Adaptive optical system after correction of non-common optical path aberration. (a) PV value and RMS value of uncorrected and closed-loop wavefronts and (b) coupling efficiency using stochastic parallel gradient descent algorithm; (c) PV value and RMS value of uncorrected and closed-loop wavefronts and (d) coupling efficiency using reverse transmission calibration algorithm

Fig. 6. Physical structure diagram of adaptive optical fiber coupling system

Fig. 7. Non-common optical path aberration in actual system. (a) Wavefront slope; (b) wavefront phase

Fig. 8. Closed-loop measurement of 1550 nm band adaptive optical system. (a) Coupling efficiencies with uncorrected non-common optical path aberration, stochastic parallel gradient descent algorithm, and reverse transmission calibration algorithm; (b) PV values and RMS values of unconverted and converted wavefronts

Fig. 9. 1.3 km field experiment. (a) Experimental link diagram; (b) physical picture of receiver

Fig. 10. Optical wireless coherent communication system using adaptive optics to improve coupling efficiency

Fig. 11. Coupling power change curves and corresponding deformable mirror surfaces under different iteration times using stochastic parallel gradient descent algorithm

Fig. 12. Measurement of non-common optical path aberration using stochastic parallel gradient descent algorithm for 1.3 km experimental link. (a) First measurement; (b) second measurement

Fig. 13. Adaptive optics without correction and closed-loop states of 1.3 km field experiment. (a) Coupling efficiency; (b) intermediate frequency signal waveform

Fig. 14. Receiver under complex environment at 10.2 km experimental link. (a) Experimental link diagram; (b) schematic diagram of receiver

Fig. 15. Adaptive optical initialization using stochastic parallel gradient descent algorithm at 10.2 km link. (a) Coupled optical power iteration curves; (b) wavefront phases

Fig. 16. Adaptive optics without correction and closed-loop states of 10.2 km field experiment. (a) Coupling efficiency; (b) intermediate frequency signal waveform