Research of On-Board Optical Switching Based on Passive Metasurface

High-capacity wireless-optical switches (WOSUs) have broken through the bottleneck of electrical rate, thus enabling low-latency and high-throughput on-board optical switching (OOS). OOS can effectively relieve the service pressure of ground networks, and it also compensates for the sparse deployment of optical fibers in complex terrains. Compared to widely-used silicon-substrate WOSUs, the passively-programmable metasurface (PMF), fabricated by us, has a golden substrate owning better radiation resistance. Without external electrical excitation for beam steering, our passive manner prolongs the service life of satellites. Moreover, by changing the incident beam polarization without consuming additional power, the data can be transferred between normal and abnormal reflected beams, thus the link backup is naturally performed. Based on multiple PMF chips, we design a novel on-board optical switching matrix (POSM), where the neural network controls chip rotation and movement with high precision. To improve OOS reliability, our enhanced optical switching control module (EOSC) solves POSM reconfiguration, once the matrix port or chip fails due to strong atmospheric drag. Finally, we establish a prototype system with the error-free transmission of ultra-high definition (UHD) video streams for the proof-of-concept, especially for verifying the natural link-backup capability of our PMF. The experimental results show <3 dB insertion loss of normal and abnormal reflected beams in the range of incident angle from 0
$^{\circ }$
to 35
$^{\circ }$
, and other meaningful results demonstrate the potential application of our PMF-cascaded POSM in highly-reliable OOS.