Demonstration of Precision Phase Locking of a Laser Phased Array to a Weak Remote Beacon

We demonstrate a sparse 3-channel Laser Phased Array (40 dBm/ch) locked to an ultra low-power (-55 dBm/ch) remote Beacon. We measured a combination efficiency ≥ 17% and 12 µs to peak power. In a nominal closed packed array the combining efficiency is about 62%. This demonstration is a key step in realizing directed energy for space applications.