Multi-parameter optical sensing platform based on III-nitride quantum well diodes

III-nitride quantum well (QW) diodes exhibit the physical phenomenon of simultaneous light emission and detection, enabling their use as multifunctional devices. Based on this property, this work demonstrates a multi-parameter optical sensing platform. Two identical QW diodes are soldered onto flexible printed circuit boards (FPCBs), with one serving as the transmitter and the other as the receiver, forming a free-space optical transmission path. By varying the distance of this free space, low-cost, miniaturized, and non-contact real-time optoelectronic sensing is successfully achieved, including distance and weight sensing. Furthermore, accurate regression of distance and weight is realized through a multilayer perceptron (MLP). The results show that the platform achieves distance sensing up to 5 cm with a 1 mm resolution, and weight sensing up to 10 g with a 100 mg resolution. With advantages such as environmental friendliness, structural simplicity, and strong scalability, this platform holds great potential for applications in flexible electronics, wearable devices, and non-contact sensing systems.