Optical networking shares rallied Thursday as investors embraced the sector’s role in AI infrastructure. Coherent (COHR) jumped 11%, Lumentum (LITE) rose 7%, and Ciena (CIEN) gained 6%, while Arista (ANET) also advanced after Bernstein initiated coverage of the group with an Outperform rating and called the companies structural AI winners. Coherent separately launched PhotonLink, an optical networking platform that uses light-based connections to move data and combines its services, photonics technologies, lasers, fibers and detectors for AI data centers. The company said it has 20 customer engagements involving co-packaged optics (CPO) and near-packaged optics (NPO), plus five engagements in emerging chip-to-chip connectivity. The launch comes as AI operators seek faster, more energy-efficient alternatives to conventional copper wiring. Goldman Sachs described optical networking as the next mega trend in AI infrastructure in April and projected a 9x total addressable market expansion to $154 billion. Nvidia announced a $4 billion investment in Coherent and Lumentum about a month before that Goldman Sachs assessment. The sector’s 2026 gains now stand at 72% for Coherent, 185% for Lumentum, 60% for Ciena and 56% for Arista.