Figure 5 | Scientific Reports

Figure 5

From: High-Capacity Free-Space Optical Communications Between a Ground Transmitter and a Ground Receiver via a UAV Using Multiplexing of Multiple Orbital-Angular-Momentum Beams

Figure 5

Beam jitter, power, and crosstalk measurements in flight environment. (a–c) Measured statistics of beam displacement with respect to the receiver centre when the UAV is static on the ground, hovering at location 1, moving from location 1 to location 2 at a speed of ~0.1 m/s, respectively. OAM +3 is transmitted and the received beam diameter is ~6.2 cm. (d) Schematic diagram of different locations where the UAV hovers. Location 1 is ~10 m above ground, ~50 m away from the transceiver with an angular position of 0°; location 2 is ~20 m above ground, ~40 m away from the transceiver with an angular position of 15°; location 3 is ~5 m above ground, ~10 m away from the transceiver with an angular position of −5°. (e) The received power on different modes in a 60-second period, when OAM −1 is transmitted and the UAV is hovering at location 1. (f–i) OAM spectrum in a 60-second period when OAM +1 is transmitted and the UAV is hovering at location 1, location 2, and location 3, and moving from location 1 to location 2 at a speed of ~0.1 m/s, respectively.

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