Fig. 1. Optical principle diagram of the magnification method by a zero-power optical module (a) Inside and (b) outside.

Fig. 2. Given the atmospheric turbulence and platform vibration, the receiving terminal is randomly located at different positions of the emission light spot.

Fig. 3. Light intensity distribution in the focal plane of the receiver by the defocusing method at: (a) the center of the transmitting light spot and (b) 1/2 of the transmitting light spot.

Fig. 4. Light intensity distribution in the focal plane of the receiver by the magnification method at: (a) the center of the transmitting light spot and (b) 1/2 of the transmitting light spot.

Fig. 5. Efficiency of the coherent receiving with different methods at different receiving positions.

Fig. 6. Structural diagram of the divergence angle switching system.

Fig. 7. Light spot in the tracking detector at different communication distances.