Space Development Agency burst-mode waveform optimized receiver

The Space Development Agency (SDA) has developed an Optical Communication Terminal standard to ensure system interoperability among a number of industry partners by defining critical technical specifications ranging from initial pointing, acquisition, and tracking to data modulation formats and error-correction protocols. In addition to time continuous intensity modulated non-return-to-zero and Manchester encoded waveforms, Version 4 of the SDA standard also supports Manchester encoded burst-mode waveforms. Burst-mode waveforms offer extended receiver power efficiency at the expense of data rate for longer range applications or size, weight, and power (SwaP) constrained terminals. In the case of optical ground stations, large area, low noise avalanche photodiodes (APDs) provide SWaP efficiency by relaxing pointing requirements via an increased receiver field-of-view relative to fiber-coupled receivers. In addition, large area APDs allow for coupling of light distorted by the atmosphere so wavefront correction using adaptive optics is not required. In this work, we present initial performance characterization results of a burst-mode optimized APD-based receiver in tandem with an SDA burst-mode waveform compliant modem.