On-orbit demonstration of inter-satellite free-space optical stable communication enabled by integrated optical amplification of HPA and LNA

Precise pointing angle deviation measurement for beaconless laser communication

How to measure the pointing angle precisely without the beacon light is crucial for beaconless laser communication. The conventional intensity method directly measures the intensity of a part of the communication signal beam, which has low sensitivity. We propose the characteristic signal method by superimposing a low-frequency sinusoidal signal on the communication signal to promote the measuring sensitivity. Simultaneously, a fast cyclic cross-correlation algorithm is used to reduce operational complexity. Compared with the experimental results of the direct intensity method, the proposed method can improve the measuring sensitivity about 9.17 dB and increase the power budget for communication about 1.96 dB.

Applications of Lasers for Sensing and Free Space Communications: introduction to the feature issue

This feature issue highlights the latest developments in laser-based sensing and free space communications. In total, 15 papers were published in Applied Optics, including an invited review paper that celebrates the legacy of David L. Fried.