Optical carrier phase recovery and locking in a Pulse-Position Modulation communication link

We have demonstrated optical phase recovery from a Pulse-Position Modulated (PPM) laser beam. Our goal is to develop and validate a laser communication and ranging method that utilizes optical coherence within the well-established scheme of PPM with photon-counting detection. Recovery of the carrier phase within optical PPM signals will enable precision Doppler tracking and ranging at optical wavelengths, benefitting spacecraft navigation and scientific measurements based on the propagation of light signals. It also has direct implications for ideal quantum-limited optical communication receivers.