Fig. 1. Experimental setup of the 60-channel active phase-locking CBC system. PM AMPs, polarization maintaining fiber amplifiers; PD, photoelectric detector.

Fig. 2. Simulation results. (a) Influence of the pinhole radius on the PIB. (b) A typical far-field intensity pattern when the radius of the pinhole is larger than the radius of the Airy disc after CBC using the SPGD algorithm. (c) A typical far-field intensity pattern when the radius of the pinhole is smaller than the radius of the Airy disc after CBC using the SPGD algorithm.

Fig. 3. (a) Shape of filter 1. (b) Shape of filter 2. (c) Equivalent filter. (d) An out-of-phase mode obtained in simulation within 2000 iterations.

Fig. 4. Acquisition diagram of a ring-shaped out-of-phase mode.

Fig. 5. Filters and simulation results of other out-of-phase modes within 1000 iterations.

Fig. 6. (a) Photograph of the SPGD controller. (b) Rear panel of the SPGD controller.

Fig. 7. Normalized cost function J in 40 s long exposure of open and closed loops.

Fig. 8. (a) Long-exposure far-field pattern of the 60 lasers in closed loop. (b) Theoretical far-field pattern of the beam array with ideal phases at the emission surface. (c) Experimental (in blue) and theoretical (in red) intensity profiles of a cross section in the far-field.