Bandwidth is per-lane speed times lane count. Push speed and you hit the SerDes energy floor; push lane count and you hit fiber and connector cost. The new fact this year: the second wall arrived first.

Marvell's 3nm FinFET 212.5Gbps SerDes hits 54.7dB reach and 2.05pJ/bit, the longest-reach and most efficient published at this rate. A shared PLL plus heavy DSP equalization breaks the old rule that reach costs power, giving 1.6T racks structurally more room in cable length and power budget.

Airoha posted record Q2 revenue and EPS of NT$5.25, but the real story is the outlook: optical communications revenue to grow more than 4x in 2026 and another 3x in 2027. Earbuds fund today's cash flow; the upside is staked entirely on pluggable optical interconnect for AI data centers.

Pluggable optics aren't hitting a speed wall — they're hitting a power and density wall. CPO moves electrical-to-optical conversion right next to the ASIC to win back power and density, and it starts in scale-up, where copper can no longer cope, rather than replacing pluggables.