Yes, as far as we know CAI use POETs interposer, in the form of POETs Starlight (based on the lightbar).  This is a packaged light source, where various components are flip-chipped onto the interposer. CAI use this as an external light source that is placed onto their host board and its function is to communicate between other AI chips and ASICS, which make-up the Photonic Fabric.  

Its worth re-reading the NR from April last  year.  There's also a YouTube vid with RK.  Poet even received an advanced PO, although I have no idea when we see revenue from that.  Or perhaps we have? 

https://www.globenewswire.com/news-release/2023/04/25/2653733/0/en/POET-Technologies-Introduces-POET-Starlight-for-the-Artificial-Intelligence-Market-and-Receives-Advanced-Purchase-Order-from-Celestial-AI.html

I suspect celestial have their own interposer and use it in other areas of the Photonic Fabric.  Which might be why there's some confusion.  But perhaps another can confirm if I'm off with that assumption. 

Until we hear otherwise, CAI and POET are still partnering and they'll be using the OI for a packaged light source