A Free-Space Optical Communication System Based on Bipolar Complementary Pulse Width Modulation.

In this work, we propose a bipolar complementary pulse width modulation strategy based on the differential signaling system, and the modulation-demodulation methods are introduced in detail. The proposed modulation-demodulation strategy can effectively identify each symbol's start and end time so that the transmitter and receiver can maintain correct bit synchronization. The system with differential signaling has the advantages of not requiring channel state information and reducing background radiation.