Have any of our resident techies checked out Dust Photonics? Sounds similiar to POET's approach. Potential partner?

https://www.dustphotonics.com/our-technology/

Optical module vendor DustPhotonics has introduced to the market its 400GBASE-DR4 QSFP-DD optical transceiver. As is the case with the company’s other optical transceivers, the new QSFP-DD leverages DustPhotonics’ AuraDP optical alignment technology that enables automated alignment for tighter integration, lower power dissipation, and improved yield. It is the company’s first optical transceiver for single-mode fiber applications.

As is the case with other devices compliant with the MSA specifications, DustPhotonics’ QSFP-DD uses an eight-lane electrical interface, with each lane carrying a PAM4 50-Gbps electrical signal. The eight electrical signals are converted into four parallel optical channels of 100 Gbps – 400 Gbps in total. DustPhotonics says its device offers bit-error ratios (BER) of 1E-15 and support of 400 Gbps across up to 2000 m.

“Our new DR4 module enables data centers and high-performance computing environments to address growing needs for higher bandwidth and speeds at the lowest cost and power per gigabit on the market,” said Anthony Musto, senior vice president of sales and marketing at DustPhotonics. “The innovative optical packaging design results in improved sensitivity and more efficient coupling, making it a valued addition to our suite of transceivers that are capable of delivering up to four-times the reliability over competing products.”

DustPhotonics says the 400GbE QSFP-DD DR4 module will be commercially available in the fourth quarter of this year. It joins the company's portfolio of optical transceiver products (see, for example, "Production ramps for DustPhotonics’ 100-Gbps QSFP28-SR4 optical transceivers").