In the face of increasing data traffic demand in short-distance optical communication and the high cost of high-speed data center interconnection, a four-level optical signal generation scheme based on dual-polarization binary-phase-shift-keying (DP-BPSK) modulator is proposed . Experimental framework of the proposed scheme consists of a laser diode (LD), DP-BPSK modulator driven by binary data, polarization controller (PC), and polarizer. The DP-BPSK modulator driven by binary data without digital analog converter, making it structurally simple and easy to implement. To verify the feasibility of the proposed scheme, 4-level pulse amplitude modulation (PAM-4) signals are generated using this scheme and transmitted over a 65km standard single-mode fiber (SSMF) at different data rates. The performance of these signals is evaluated based on the experimental results, including the eye diagrams and bit error rate (BER), which indicates that the transmitted signals have a high quality. Therefore, the proposed scheme has promising application potential in future short-distance optical communication.