This project will advance optical communications interlinking between small spacecraft using pulse position modulation. The Miniature Optical Communications Transceiver (MOCT) consists of a novel software-defined pulse modulator, integrated laser system, and avalanche photodetection system. At the end of the project, MOCT will be tested for a future CubeSat flight demonstration mission.

Because the pulse timing is generated using programmable delays within a field-programmable gate array, it does not require a power hungry gigahertz slot clock or processor. Instead, a low power 10 megahertz chip-scale atomic clock is used to continuously calibrate the timing delay chain. The timing resolution of this system is roughly a factor of four better than previously flown systems, meaning that it can transmit more bits of data with each optical pulse. Because this technology can both generate and time-stamp the arrival of short optical pulses with 50 ps precision, it simultaneously provides power efficient communications and relative ranging between small spacecraft at the cm-level.