I don't usually post patent applications, but this one is interesting. For those who want to see illustrations of how Poet's interposer PIC (photonic integrated circuit) structures and assemblies are formed.
A lot of details (starting page 9)
Date of patent application : November 21, 2022 (published july 20, 2023)
Patent application number : US-20230228953-A1
Inventors : Suresh Venkatesan, San Jose, CA (US); Jing Yang, Singapore (SG); Lucas Soldano, San Jose, CA (US)
Self-Aligned Fanout Waveguide Structure on Interposer with Linear Multicore Optical Fiber
https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/20230228953