Fig. 1. Schematic of photon detection array receiver system

Fig. 2. Flow chart of timing error estimation

Fig. 3. Statistical charts of photon distributions. (a) γ=0, τ=0; (b) γ=1×10-5, τ=0; (c) γ=0, τ=0.2

Fig. 4. Photon distributions with different γs and τs. (a) H=10; (b) H=2

Fig. 5. Comparison of BER performance. (a) MSE and M2 synchronization in case of H=2, 4, 10; (b) basic likelihood ratio and improved likelihood ratio

Fig. 6. Comparison of BER performance. (a) Number of detectors N is 4, 8, 16, respectively; (b) normal circumstance and signal interruption

Fig. 7. Effect of laser pulse width on BER performance of M2 synchronization