Free-space optics naturally offers multiple-channel communications and sensing exploitable in many applications. The different optical beams will, however, generally be overlapping at the receiver, and, especially with atmospheric turbulence or other scattering or aberrations, the arriving beam shapes may not even be known in advance. We show that such beams can be still separated in the optical domain, and simultaneously detected with negligible cross-talk, even if they share the same wavelength and polarization, and even with unknown arriving beam shapes. The kernel of the adaptive multibeam receiver presented in this work is a programmable integrated photonic processor that is coupled to free-space beams through a two-dimensional array of optical antennas. We demonstrate separation of beam pairs arriving from different directions, with overlapping spatial modes in the same direction, and even with mixing between the beams deliberately added in the path. With the circuit’s optical bandwidth of more than 40 nm, this approach offers an enabling technology for the evolution of FSO from single-beam to multibeam space-division multiplexed systems in a perturbed environment, which has been a game-changing transition in fiber-optic systems.

自由空间光学自然提供可在许多应用中利用的多通道通信和传感。然而，不同的光束通常会在接收器处重叠，并且，特别是在大气湍流或其他散射或像差的情况下，到达的光束形状甚至可能事先不知道。我们表明，即使它们共享相同的波长和偏振，甚至具有未知的到达光束形状，这些光束仍然可以在光学域中分离，并同时检测到可忽略不计的串扰。在这项工作中提出的自适应多波束接收器的内核是一个可编程的集成光子处理器，它通过一个二维光学天线阵列耦合到自由空间光束。我们展示了从不同方向到达的光束对的分离，在同一方向上具有重叠的空间模式，甚至在路径中故意添加了光束之间的混合。凭借超过 40 nm 的电路光带宽，这种方法为 FSO 从单光束到多光束空分复用系统在扰动环境中的演进提供了支持技术，这一直是光纤领域中改变游戏规则的过渡系统。