CPO light sources aren't limited to external ELSFP at 400 mW. TeraHop saves 3 dB by building the laser into NPO, and Lumentum's own specs put NPO at 21–23 dBm vs. 25–26 dBm for CPO. A 3–4 dB lower bar puts Taiwan's CW laser chain right at the door of this window.

At ECOC 2026, 12 speakers weren't really arguing CPO vs pluggables — they were arguing about the SerDes at the XPU edge. Arista's XPO and Broadcom/NVIDIA CPO bet on 200G→400G PAM4; OCI and DWDM bet on slow-and-wide NRZ. 2027–2028 belongs to fast-and-narrow; slow-and-wide must wait for the gearbox tax to hit zero.