Link Budget for Free-Space Laser Time Transfer Between Ground Clock Stations

Free-space links free a clock comparison from fibre geography, at the price of geometric loss and atmospheric variability. A credible design must show received power, photon rate and timing jitter together, because a link that closes in power can still fail in timing precision. This paper sizes a ground-station laser time-transfer terminal with stated apertures and transmit power, propagates the geometric loss over an eight-hundred-kilometre path, and converts the resulting timing jitter into a range and potential equivalent. The computed results, taken from the deposited script, are as follows in summary: The computed received_power_W is 0.000122. The computed photon_rate_per_s is 9.51e+14. The computed timing_jitter_ps is 10. The computed one_way_range_equiv_m is 0.003. The computed link_margin_note is geometric. The study is a computation from stated assumptions, not a measurement, and its figures should be read at the precision those assumptions support. SIMULATED, NOT MEASURED.