Once the laser is moved off the chip, someone has to catch that +20 dBm high-power light. AIST shows that polymer waveguides on low-cost glass-epoxy substrates can do it: zero degradation over six hours and only a 4.4°C temperature rise — a key feasibility endorsement for the packaging-centric CPO route.

At ECOC 2026, Coherent skipped the CPO sales pitch and brought a working machine: a 6.4T NPO with its own ELSFP at 4.7 pJ/bit — laser included. LightCounting puts the crossover at 2031. The CPO debate is over; what remains is a fight over the slope.

Meta, Broadcom and AMD jointly define the OCI 200G line interface spec, betting scale-up optical interconnect on micro-ring DWDM, bidirectional single fiber, external lasers and NRZ. It is a buyer-supplier alliance taking on NVIDIA's vertical integration, and its external laser clause draws a clear spec for CW DFB and ELSFP suppliers.