Polarization-Basis Tracking Scheme in Satellite Quantum Key Distribution

Figure 3

1.5-μm optical output signal after polarizer with the angular difference between the transmitter and receiver of 0^∘≤|Δ𝜃|<45^∘. (a) The 1.5-μm optical output signal after the polarizer and (b) the applied voltage (20 : 1) for the polarization modulator are shown as Ch1 and Ch3 with the modulated frequency of 20 kHz.