Do you think there's a link or that I'm crazy? Maybe it's both.

ZKTEL QSP-DD 400GBase-DR4 PAM4

"QSFP-DD 400GBASE-DR4 silicon photonics transceiver is based on a new state-of-the-art silicon photonics (SiPh) platform. It uses SiPh chips that integrate a number of active and passive optoelectronic components, 3D packaging technology and industry-leading 7nm DSP chips. It is a cost-effective and lower power consumption solution for 400GBASE data center."

Mentech 800G OSFP DR8

"MHCG8D5-DNC-8VT1 is designed to transmit and receive serial optical data links up to 106.25 Gbps data rate (per channel) by PAM4 modulation format over single-mode fiber. It is a small-form- factor RHS hot pluggable transceiver module base on high performance SIP modulator. It is compliant with 800G Ethernet, OSFP MSA."

Exactly the same optical specifications for zktel and Mentech products when looking at the datasheets.

Accelink 1.6T OSFP-XD DR8 

"RTXM700-300 is designed to transmit and receive serial optical data links up to 212.5 Gb/s data rate (per channel) by PAM4 modulation format over single-mode fiber. It is a small-form- factor hot pluggable transceiver module base on high performance SIP modulator. It is compliant with 1600G Ethernet specs and OSFP-XD MSA."

Exactly the same description as Mentech. SIP stands for system in package and is what POET offers.