The Photonics Two-Track — SemiAnalysis Pushed Out CPO, TSMC Lit Up Its CoPoS Validation Line the Same Week
While five optical-comm names locked limit-down, Largan committed to a September FAU pilot line and TSMC's CoPoS took delivery of validation materials
The Photonics Two-Track
On June 11, five Taiwan optical-communication and silicon-photonics names locked limit-down. The proximate trigger was an institutional SemiAnalysis note circulated the night before, warning that co-packaged optics (CPO) volume ramps slip to 2028–2029 — optical-engine yields, ASIC redesigns and PCB constraints all pulling the timeline out. The tape read it as a one-year delay and dumped Applied Optoelectronics and the rest of the cohort.
The trouble is, the same week — through different channels — Taiwan committed in the opposite direction. Largan (3008-TW) CEO Lin En-ping told shareholders the first silicon-photonics FAU (Fiber Array Unit) pilot line, fully automated, will be complete by September. TSMC (2330) entered the core validation phase of its CoPoS (Chip-on-Panel-on-Substrate) advanced packaging line after taking delivery of key materials and consumables. Citi, on the ground at COMPUTEX, characterized the CPO supply chain as "pre-explosion phase" with rack-scale deployment now starting — Nvidia's Spectrum-6 SPX CPO racks shown live.
This isn't a thesis fight. It's a calendar fight. Both camps agree CPO is coming. The dispute is 2027 or 2029.
The two Taiwan cohorts are pricing the gap differently. The calendar camp — optical-comm and silicon-photonics names — was modeled on a 2027 ramp. Slip the ramp 12–18 months and the NPV breaks. So the tape printed limit-down. The capacity camp — TSMC CoPoS, Largan's FAU pilot, ASE's 43-month-high May print at NT$63.0B (+28.6% YoY) — is sizing capex for 2028–2029 capacity readiness, not for a precise 2027 ramp. Get the pilot line lit in September and the volume decision later is still on the table.
The May prints make clear why the split is happening at all. TSMC May revenue NT$416.9B (+30.1% YoY) — a fresh record. ASE NT$63.0B — a 43-month high. Delta (2308) NT$58.96B (+43.6% YoY, second-highest ever). Lite-On (2301) NT$17.35B (+29.6% YoY, with cloud revenue up ~80% YoY). Compal NT$70.46B (+22.3% YoY). Chenbro NT$2.52B (+37.3% YoY, limit-up at NT$1,510). Taiwan May exports $78.48B (+51.7% YoY) — second-highest monthly print ever, with electronic components at an all-time monthly record. The AI compute side prints today regardless of CPO timing.
That's the analytic fork. If CPO slips 12–24 months, TSMC CoWoS, ASE advanced packaging, Delta power-and-thermal, Lite-On cloud (+80% YoY) — the entire "already working today" stack — is unaffected. A slipped CPO actually extends the runway for current pluggable optics. So the capacity camp keeps deploying capital.
The week brought two more capital reallocations along the same axis. Powerchip (PSMC, 6770) priced a Luxembourg GDR for $886M (~NT$27.8B, 5.73% discount) to fund its 3D AI foundry push. Taiwan Mask (2338) sold its underutilized Zhunan Fab 6 to ASE subsidiary SPIL for NT$2.8B — legacy mask-shop real estate flowing into advanced packaging. Neither move is timed to a CPO ramp date. Both are timed to .
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