While considerable research has been conducted on the structural principles, fabrication techniques, and photoelectric properties of high-voltage light-emitting diodes (LEDs), their performance in light communication remains underexplored. A high-voltage series-connected LED or photodetector (HVS-LED/PD) based on the gallium nitride (GaN) integrated photoelectronic chip is presented in this paper. Multi-quantum wells (MQW) diodes with identical structures are integrated onto a single chip through wafer-scale micro-fabrication techniques and connected in series to construct the HVS-LED/PD. The advantages of the HVS-LED/PD in communication are explored by testing its performance as both a light transmitter and a PD. The series connection enhances the device's 3 dB bandwidth, allowing it to increase from 1.56 MHz to a minimum of 2.16 MHz when functioning as an LED, and from 47.42 kHz to at least 85.83 kHz when operating as a PD. The results demonstrate that the light communication performance of HVS-LED/PD is better than that of a single GaN MQW diode with bandwidth and transmission quantity, which enriches the research of GaN-based high-voltage devices.