MACOM's Data Center Inflection: More Than 40% Growth, But the Real Story is Optical Content

MACOM's fiscal Q3 (ending July 3, 2026) delivered the kind of numbers that make investors sit up: revenue of $342.2 million, up 35.8% year-over-year and 18.4% sequentially; adjusted EPS of $1.40; and a record book-to-bill of 1.6:1. The company guided fiscal Q4 revenue to $415–425 million, implying another 22% sequential jump, and management sketched a base case for fiscal 2027 of mid-20s growth — with Data Center alone up about 50%. The call was a torrent of product wins, capacity expansions, and a confident tone about the next two years. But stripping away the aggregates, the most consequential news is that MACOM is no longer just an analog chip supplier; it is becoming a vertically integrated optical components player, with indium phosphide photodetectors and, eventually, CW lasers as the new growth engines.

The Data Center Accelerator

Data Center revenue hit $137.6 million in Q3, up roughly 40% sequentially, and the segment is on track to grow about 74% for fiscal 2026. Steve Daly credited the surge to 200G per lane PAM4 products, which are now the primary driver of growth across pluggable modules, and to a broad portfolio spanning EML, silicon photonics, and VCSEL architectures. “Demand for our products is strong across our three end markets, and our backlog continues to build,” — Stephen Daly, Chief Executive Officer · 2026-08-06 he said. The increasing demand is also showing up in the company's customer diversification — from 8 customers over $10 million two years ago to over 20 today, with a few in the $50–100 million range. Book-to-bill has been 1.3, 1.5, then 1.6 across the last three quarters, a streak that gave management confidence to forecast a strong FY27 without official guidance. “If you were just to take the midpoint of our Q4 guidance and annualize that into our fiscal '27, you're going to see numbers that are in the mid-20s, 27%, 28% as a company,” — Stephen Daly, Chief Executive Officer · 2026-08-06 Daly added.

Indium Phosphide: The Next Frontier

The real step-change is in photonics. MACOM's 200G photodetectors are ramping in volume and have become "a meaningful contributor to our overall Data Center growth," while the 400G PD is in customer hands. The Indium Phosphide products line is being expanded with incremental fab capacity, and the company is pulling forward its CW laser plans. The 75mW CW laser is still in qualification, but management is confident enough to plan for potential production start in late calendar 2027.

If we're able to bring a CW laser into production in 2028, that's a watershed moment. That will be a big number that will really drive tremendous growth.

This is a departure from prior quarters, where CW laser was always "six to twelve months away." The tone has shifted from exploratory to executional. The company is also leveraging its chip designers to push ahead in TIAs and drivers for 200G and 400G per lane, and it is investing heavily in R&D — $250 million this year, nearly double what it spent three years ago. The gross margin trajectory confirms the mix shift: Q4 guidance of 60–61% is well above the 54–56% range of the past two years. Q3 adjusted gross margin rose 120 bps to 59.7%, and the company expects sequential increases of 25–50 bps per quarter through FY27.

Defense, LEO, and the Long Game

Beyond data center, MACOM is positioning itself in two other large, durable markets. Industrial & Defense revenue was $133.4 million in Q3, up 11% sequentially and at a record, with Defense expected to grow ~25% this fiscal year. The company's LEO market push is gaining traction, with new wins in next-generation optical communications for satellites and a growing European defense presence. The MESC fab in France is completing its 3-inch to 6-inch conversion, and management hinted at a major U.K. defense order. “I think over the next month or 2, I'm told we're going to get one of the largest orders in MESC's history for a U.K. defense company that's working on airborne defense systems,” — Stephen Daly, Chief Executive Officer · 2026-08-06 Daly said.

The company also continues to benefit from competitor exits in RF power and from a broader secular build in test-and-measurement and automotive markets. Yet the risk landscape is shifting. The proposed U.S. ban on Chinese transceiver module makers could redirect business to other suppliers that MACOM also serves. “We have relations with all of the transceiver companies in the industry,” — Stephen Daly, Chief Executive Officer · 2026-08-06 Daly noted, but the ultimate customer mix could change. The company's exposure to China is minimal — no manufacturing there, only ~85 employees in sales and logistics — so the risk is more about a shift in who buys its chips than about tariffs.

Valuation and the Tape

Despite the rosy outlook, the stock has not been celebrating. MTSI is down over 30% from its May 2026 peak of $400.66, even as the company reports accelerating growth. The valuation has compressed — price-to-revenue is still 15.5x, but price-to-operating income has fallen to 87.6x from a peak of over 300x. The market may be pricing in a cyclical peak in AI capex, or it may be concerned that the data center growth rate is unsustainable. Management's own guide implies a slowdown from 74% growth this year to ~50% in FY27 — still blistering, but a deceleration.

The key debate now is execution: can MACOM convert its CHIPS Office funding negotiation, its internal fab expansions, and its CW laser qualification into the revenue growth model suggests? If the laser lands, the stock re-rates; if not, the optical story gets lumpier. The company's disciplined capital spending ($60–65M in FY26) and net cash position of ~$322M provide a cushion, but the market will want to see the (already strong) backlog convert to cash at the pace implied by the guidance. This is a classic case of a well-run compounder hitting an inflection point, yet facing the judgment of a tape that has already discounted a lot.