Lumentum's stock experienced a significant intraday plummet of 8.15% on Tuesday, marking a sharp reversal in trading sentiment.

The decline appears linked to market dynamics within the AI optical interconnect sector. Recent reports indicate that Advanced Micro Devices is accelerating efforts to build out its own optical interconnect supply chain, aiming to reduce dependence on the NVIDIA ecosystem. This strategic shift is drawing significant attention to companies involved with continuous wave (CW) lasers, a critical component where Lumentum holds an approximately 90% market share.

While Lumentum and competitor Coherent have their CW production capacity reportedly booked until 2028, AMD's push to secure large-scale purchase agreements for high-power CW laser chips from alternative suppliers may be raising investor concerns about future competitive pressures and supply chain dynamics. Furthermore, the industry faces acknowledged challenges in the large-scale commercialization of co-packaged optics, including manufacturing yield issues and persistent supply shortages for indium phosphide substrates, which are essential for laser production.