Fig. 1. Structural design of InGaAs/InP SPD. (a) Schematic of the typical InGaAs/InP SPD structure; (b) simulated I-V curves of InGaAs/InP SPD with and without the reflection layer; (c) electric field profile at 66 V for the old generation InGaAs/InP SPD； （d） electric field profile at 70 V for the new generation InGaAs/InP SPD； （e） vertical electric field at cut1 in Fig.1（c） and Fig.1 （d）； （f） horizontal electric field at cut2 in Fig.1（c） and Fig.1 （d）

Fig. 2. Measured photocurrent and dark current varing with reverse bias under illumination of light with optical power of 1 μW as well as the multiplication gain at different temperature

Fig. 3. Sample and working principle diagram of SPAD. (a) SPAD module sample; (b) SPAD circuit principle; (c) module control software interface

Fig. 4. PDE changing with overbias, DCR changing with PDE, and P_ap changing with PDE tested at different temperature

Fig. 5. Experiment of SPAD laser communication. (a) Experimental setup of laser communication experimental device; (b) FPGA module with integrated transceiver function

Fig. 6. Bit error rate (BER) test of NFAD. (a) BER test results obtained by sending 1000 manual codes; (b) BER test results