On August 13, according to BIT (bit.com) market data, the US optical communication sector opened mixed, with 'optical communication giant' Coherent dropping over 3% despite its latest quarterly earnings guidance significantly exceeding market expectations. The company reported Q4 revenue of $2.05 billion, a 34% year-over-year increase, surpassing the expected range of $1.98-2.02 billion. For Q1, it anticipates revenue of $2.20-2.40 billion, higher than the expected $2.13 billion, with adjusted EPS projected at $1.85-2.05, exceeding the expected $1.77. The Pure Photonics ETF FOTO rose 0.05%; Corning (GLW) fell 0.19%; Marvell Technology (MRVL) increased by 1.73%; Applied Optoelectronics (AAOI) declined by 1.10%, focusing on high-speed optical modules (800G/1.6T) for AI data center transceivers; Lumentum Holdings (LITE) fell 0.39%, a key supplier of optical communication lasers and modules for major AI data center manufacturers; Coherent Corp (COHR) dropped 3.76%, a leader in lasers, optical components, and photonic solutions covering data centers and industrial sectors; Ciena Corporation (CIEN) rose 0.93%, producing high-speed SerDes and connectivity chips focused on low-power interconnects for AI data centers.