This article presents a study on multi-junction cascaded vertical-cavity surface-emitting lasers (VCSELs) that achieve high power conversion efficiency (PCE). The research demonstrates that a 20-junction VCSEL can achieve an energy conversion efficiency of over 88% at room temperature through simulation. Experimental results show that a 15-junction VCSEL achieves a maximum PCE of 74% under nanosecond driving current, with a differential quantum efficiency exceeding 1100%, which is the highest reported for VCSELs. The study highlights the potential of multi-junction VCSELs to surpass the efficiency of edge-emitting lasers (EELs), which have traditionally been the most efficient semiconductor lasers. The efficiency improvement is attributed to the cascading of multiple active regions, which increases the gain volume and allows for higher differential quantum efficiency. The research also addresses the challenges of VCSELs, such as high threshold current and resistance, and proposes solutions through optimized design and fabrication. The study emphasizes the importance of improving VCSEL efficiency for future applications in intelligent systems, communication, and other fields where energy consumption is a critical concern. The results show that multi-junction VCSELs can significantly enhance PCE while maintaining low power consumption, making them a promising candidate for high-efficiency laser sources. The study also discusses the scalability of multi-junction VCSELs and their potential for future applications in high-speed communication and other advanced technologies.This article presents a study on multi-junction cascaded vertical-cavity surface-emitting lasers (VCSELs) that achieve high power conversion efficiency (PCE). The research demonstrates that a 20-junction VCSEL can achieve an energy conversion efficiency of over 88% at room temperature through simulation. Experimental results show that a 15-junction VCSEL achieves a maximum PCE of 74% under nanosecond driving current, with a differential quantum efficiency exceeding 1100%, which is the highest reported for VCSELs. The study highlights the potential of multi-junction VCSELs to surpass the efficiency of edge-emitting lasers (EELs), which have traditionally been the most efficient semiconductor lasers. The efficiency improvement is attributed to the cascading of multiple active regions, which increases the gain volume and allows for higher differential quantum efficiency. The research also addresses the challenges of VCSELs, such as high threshold current and resistance, and proposes solutions through optimized design and fabrication. The study emphasizes the importance of improving VCSEL efficiency for future applications in intelligent systems, communication, and other fields where energy consumption is a critical concern. The results show that multi-junction VCSELs can significantly enhance PCE while maintaining low power consumption, making them a promising candidate for high-efficiency laser sources. The study also discusses the scalability of multi-junction VCSELs and their potential for future applications in high-speed communication and other advanced technologies.