IgotBannedForSayingRedditWasBetter: As far as I can tell flip chipping the lasers seems like the better approach.

Yes, this is something POET has pointed out several times; it’s part of the flexibility of the Interposer platform: You can always use the best laser available on the market, or the laser that is best suited for your application, from a manufacturer that specializes in just that. If laser A doesn’t meet your needs, you just use laser B. That should always be better and faster than developing your own mediocre laser that is somehow grown on the substrate. The only requirement is that the manufacturer of the desired laser (or other active device) must build a version with a connector that fits into the socket of the interposer.