One of the great advantages of doing photonics in silicon is the opportunity to reuse design IP within a standard process.  Nowadays we take this for granted, but not that long ago, this was a radical idea.  The OpSIS Institute, which Dr. Hochberg directed, was formed to popularize the idea of creating openly-accessible Process Design Kits, or PDK's, which included a large number of key building blocks for photonic integrated circuits.  Users could take these elements and assemble them into complex photonic circuits, without having to design the elements.  This saved a lot of time and a lot of engineering effort, because it turns out that almost everyone needs the same basic elements for their photonic integrated circuits.  

At OpSIS, it was extremely exciting to see all of the new ideas that people were able to explore in the shared MPW runs.  Nowadays, there's an entire foundry ecosystem where the availability of PDK's for silicon photonics is taken

for granted.