Compact dual-comb time-transfer and ranging for future space-based distributed sensing

We describe a general design for a compact frequency comb-based optical time transfer and ranging node with a volume of 14L, a mass of 10 kg, and a power consumption of 46 W. We assess the residual noise from the comb-based system by making both ranging and time transfer measurements using these compact nodes over a 4.4 km free-space testbed. We demonstrate that this node design has the potential to support sub-femtosecond clock comparisons and sub-micron range measurements at averaging intervals of 1 s with a mean received power of 20 nW. This is more than sufficient to support future space-based distributed coherent sensing at observing frequencies beyond 1 THz.