Lumentum's fiscal fourth-quarter report showed revenue rising 109%, and its stronger future guidance helped push optics-related stocks higher, including AXT and Ciena. The move highlights growing investor focus on optical connectivity infrastructure tied to AI workloads, where faster data movement between chips, servers and data centers has become a key investment theme. The debut of the Roundhill Photonics & Optics ETF, trading under LYTE, adds a dedicated ETF for investors seeking concentrated exposure to photonics and optics companies linked to that trend.