Coherent Corp. FY2026 Annual Report: Capex Climbs 150% to $1.10B on AI Optical and SiC Buildout, September 2026

Coherent Corp.'s FY2026 annual report shows capital expenditure rising 150% to $1.10 billion against $7.12 billion in revenue, as the company accelerates InP optical transceiver capacity under a CHIPS Act commitment and begins 300mm SiC substrate sampling for AI infrastructure.

Coherent Corp. filed its fiscal year 2026 annual report alongside a material-event 8-K on September 10, 2026, marking the close of the most capital-intensive year in the compound-semiconductor and photonics company's history. Capital expenditure reached $1.10 billion for FY2026, a 150% increase from $441 million in FY2025, against reported revenue of $7.12 billion — a capex intensity of 15% that ranks the company fourth among fifteen chip-sector peers by that measure, according to Slicast's XBRL-derived data. The stock fell 3.4% to $293.17 on the filing date, a reaction that likely reflects investor scrutiny of whether the buildout will convert to earnings within a credible window.

The strategic rationale sits at the intersection of two AI infrastructure constraints. The first is optical interconnects: as GPU clusters scale into the hundreds of thousands of units, copper-based electrical links encounter hard limits on bandwidth density and power consumption, driving demand among hyperscalers for Indium Phosphide-based transceivers of the type Coherent manufactures. A July 2026 market analysis noted strong AI optics and laser backlog at the company, specifically citing infrastructure optical interconnects as a demand driver that had moved beyond the ceiling of electrical alternatives — a structural rather than cyclical shift. The second is power delivery to AI accelerator hardware: silicon carbide power electronics are increasingly specified in the conversion stages feeding high-density GPU racks, and Coherent supplies SiC substrates into that segment of the supply chain.

Both product lines received meaningful external validation in 2026. In June, Coherent announced a CHIPS and Science Act Letter of Intent for up to $50 million in direct Commerce Department funding, earmarked for expanding its six-inch Indium Phosphide operations at Sherman, Texas. That document is not yet a binding disbursement, but the Commerce Department's engagement signals that the Sherman InP line is regarded as strategically important to the domestic supply chain. Then, in August, Coherent disclosed the start of customer sampling for 300mm high thermal conductivity SiC substrates designed for AI infrastructure applications. The move to 300mm is technically significant: SiC substrates are predominantly produced at 150mm today, and doubling the diameter increases usable wafer area by approximately four times — a potential step-change in per-unit cost if yields on the new geometry prove viable. No commercial SiC manufacturer has yet qualified 300mm for volume production, meaning Coherent's sampling announcement is simultaneously a technical milestone and an unproven commitment.

The scale of the capital commitment comes into sharper relief against a longer historical record. Slicast's XBRL coverage of Coherent spans 69 reporting periods from 2009 through 2026; the highest single-period capex on record was $139 million in the quarter ending September 2022 — a period when the company was integrating a major merger. The $1.10 billion FY2026 figure implies a quarterly run rate roughly double that historical peak. At 15% of revenue, the intensity is well above the semiconductor sector median and places Coherent in the upper quartile of capital commitment among its tracked peers. Converting that outlay into free cash flow requires not only sustained demand from hyperscaler customers — whose purchasing cycles are notoriously lumpy — but also successful execution on production ramps that span multiple fiscal years.

The risks are neither small nor abstract. The 300mm SiC sampling announcement, while strategically significant, describes a pre-qualification stage; the path from customer sampling to volume production on an entirely new substrate diameter typically spans multiple quarters to years, involving tool procurement, process characterization, and customer qualification audits. The Sherman InP expansion rests on an intent document, not a contract; actual capital relief and a binding timeline remain contingent on agreement execution. In the optical transceiver market, Coherent competes with Lumentum and Fabrinet-networked suppliers, while several hyperscalers have signaled interest in co-packaged optics and in-house integrated photonics, which over the medium term could shift procurement leverage. If revenue growth in FY2027 does not move broadly in step with the expanded asset base, free cash flow will come under pressure at a time when the stock already carries a meaningful premium over historical valuation averages.

Three near-term indicators will clarify whether the capital program is tracking to plan. First, the rate of 300mm SiC design-win announcements: qualification by a Tier 1 power semiconductor manufacturer would provide the most tangible evidence that the new substrate geometry is production-viable. Second, the formal execution of the CHIPS Act funding agreement for Sherman, which would simultaneously provide capital relief and impose a public ramp-rate commitment. Third, and most immediately actionable, the FY2027 first-quarter results: the ratio of backlog conversion to new-order intake will be the earliest quantitative test of whether AI infrastructure demand is translating into recognized revenue at the pace the FY2026 capex level implies. The annual report filed on September 10 lays out the balance sheet; the next two earnings cycles will judge the bet.