Demonstration of a single-aperture, full-duplex communication system

The ability to simultaneously transmit and receive (STAR) through the same aperture is a key capability that will enable full duplex use of communications channels. We report the first demonstration of a single-aperture STAR system, which was enabled by a recent advance in microwave photonics: a new type of optical link that has high transmit- to-receive (T/R) isolation over a broad bandwidth. We measured 14 key performance metrics on a prototype system; key among these was T/R isolation. T/R isolation > 100 dB is projected for the technique; isolation as high as 85 dB was measured, which is the highest reported to date.