Picosecond wireless synchronization using an Optically Locked Voltage Controlled Oscillator (OL-VCO)

In this paper, the first fully integrated Optically Locked Voltage Controlled Oscillator (OL-VCO) is reported. The OL-VCO is locked to an RF source through a free-space optical link at λ=850 nm. In the locked mode, the OL-VCO achieves an RMS jitter of 1.6 psec with 16 averaging. It also improves the phase noise by 25 dB at 100 Hz offset frequency. The wireless synchronization is achieved at a distance of 1.5 m, representing more than two orders of magnitude improvement compared to the prior art.