Silicon photonics' original sin is that it can't emit light. Lasers hate heat, yet CPO asks them to sit next to a hot chip — making the light source the reliability ceiling, where one failed laser can cost an entire optical engine. External vs integrated sources and four light-source types each bet on a different future.

Four keynotes and a panel: eight speakers made the same point in five different ways — interconnect has graduated from component to architecture. Yet the most honest line of the day came from the moderator's close: today's real dilemma isn't technology, it's that we lack the materials to build AI infrastructure.

The light-source race has switched tracks: it's no longer about whose laser is brighter, but who can make billions of them by 2030 without spending 5 minutes of active alignment on each. At ECOC 2026, two sessions and 11 speakers delivered eight technology paths and an 18 dB bill.