Coherent stock jumps 10% on PhotonLink, Bernstein start

Coherent rose about 10% and Lumentum 9% as Bernstein began coverage at Outperform and PhotonLink drew fresh attention to AI stocks in optical networking.

Lead

Shares of Coherent (NYSE: COHR) climbed roughly 10% to $315.71 on Thursday, October 1, 2026, and Lumentum Holdings (NASDAQ: LITE) added 9% to $1,058.42. The moves followed Bernstein's decision to start coverage of both companies at Outperform and Coherent's launch of its PhotonLink integrated optics platform for AI data centers. The rally stood out in a flat tape: the SPY S&P 500 ETF slipped 0.2% to $761.11.

What Happened to Coherent and Lumentum Shares?

Coherent and Lumentum rose in tandem because two catalysts landed on the same optical-components theme. Bernstein initiated Outperform ratings on both, as part of a broader networking and optical review. The same review rated Ciena (CIEN) and Arista Networks (ANET) at Outperform, and Cisco (CSCO) and Corning (GLW) at Market Perform.

Corning gained about 3% to $158.89. The Roundhill Photonics & Optics ETF rose roughly 4% to $25.40, a sign that buying extended across the group instead of staying with two names.

What Is Coherent's PhotonLink Platform?

PhotonLink is an integrated optics platform that bundles Coherent's lasers, silicon photonics, precision optics, specialty fibers and detectors with assembly and test capability. It targets three connection types inside AI clusters: chip-to-chip links, rack-internal links and high-capacity data center links.

Coherent said it has more than 10 customer engagements for co-packaged optics, where optical engines sit beside the processor, and more than 10 for near-packaged optics. It reported more than five engagements in chip-to-chip connectivity, with anchor customers and long-term agreements in place. Revenue from the platform is expected to begin ramping in the fourth quarter of calendar 2026.

The company is expanding indium phosphide and specialty fiber capacity to support that ramp. The pitch to investors is vertical integration: owning the materials, lasers and modules reduces dependence on outside suppliers at a time when high-end components are tight.

Why Are Optical Suppliers Drawing Investor Attention?

Optical suppliers are drawing attention because AI data center build-outs are shifting bandwidth demands from copper to light, and supply of advanced components remains constrained. Bernstein's characterization of the group as structural winners reflects that view.

Lumentum supplies the earnings evidence. Its fiscal fourth-quarter revenue reached $1.006 billion, up 109.3% from a year earlier, with adjusted earnings of $3.23 per share against a consensus of $2.97. It guided first-quarter revenue to $1.225 billion to $1.275 billion, and shipments of its optical circuit switches doubled from the prior quarter. Together with PhotonLink's launch, the figures show why ai stocks tied to networking are being treated as a distinct trade from chip designers.

What Comes Next for AI Optics Stocks?

The next test for Coherent is conversion: turning more than 20 co-packaged and near-packaged engagements into shipments when revenue begins to ramp in the fourth quarter. Capacity additions in indium phosphide and specialty fiber are the operational variable to watch.

For Lumentum, attention shifts to delivery against its first-quarter revenue range. Moves of 9% to 10% in a single session leave both stocks sensitive to any change in hyperscaler spending signals or component supply.

Outlook

Coherent and Lumentum closed the session sharply higher as new broker coverage and a product launch reinforced the case for optics in AI infrastructure. The sector now has a visible catalyst calendar: PhotonLink's fourth-quarter revenue start, Lumentum's first-quarter guidance and continued data center capital spending.