I think the capacity is in place at SilTerra for some serious production already. But it would not surprise me if they have already established where additional  capacity is. Recall that POET was working with SilTerra for several months before they signed a deal and that the new equipment was already purchased before the news was disclosed.

As per the AGM

Transitioned dielectric waveguide process technology from a development lab to its own equipment in the SilTerra foundry to enable a seamless high-volume manufacturing ramp

From the SilTerra announcement.

Suresh:

The combined resources and investments of the two companies enables us to establish a unique manufacturing process as well as a reliable supply of wafers for our Optical Interposer.

As a result of this partnership, Poet has now secured a key element in the commercialization process, allowing us to establish more engagements with prospective customers."

2 ½ months later we learn that the equipment is already in place and commissioned.

And if we are looking for some validation of the unique nature of the platform from a third source the CEO of SilTerra had this to say:

"SilTerra is delighted to be working with Poet in what we regard as a key strategic engagement to address the increasing need for cost-effective solutions for data centre interconnects through the innovative use of silicon in photonics. Poet's Optical Interposer is a major advance over other approaches to optical interconnects and facilitates the co-packaging of electronics and photonics devices in a single multichip module (MCM). Poet's photonics-in-a-package solution has the potential to address even larger markets in the future for the integration and co-optimization of ASICs and DSPs with photonics at the interposer and chip level. We at SilTerra look forward to a long and prosperous relationship between our two companies and our teams."