Respectfully, here is a quote from Mr. Chen his expertise is photonics...

“This 400G receiver utilizes a truly game-changing technology that will make POET's approach of hybrid silicon photonics a force to reckon with in the 400G/800G FR4 module market,” said Ben Chen, Chief Technology Officer of Surinno Photonics (formerly Hengtong-Rockley).  “POET Technologies has been able to utilize its platform concept to provide easy-to-use optical engines for the data communications market with rapid deployment and demonstrations of 100G/200G TX-RX engines and also 400G FR4 engines.  It’s amazing technology.”