See also oz4ms’s post: https://agoracom.com/ir/POETTechnologies/forums/discussion/topics/705510-side-note/?message_id=2187997#message

Gentlemen

and then Mellanox throws the towel .... (thanks go to wake)

12 January 2018, Fibre-System - Mellanox ceases 1550nm silicon photonics development
Mellanox Technologies is stopping development of its 1550nm silicon photonics technology and products, effective immediately. About 100 people will lose their jobs as a result.
Mellanox gained its silicon photonics activities through the 2013 acquisition of Kotura in a deal valued at $82 million. The start-up had developed a line of variable optical attenuators (VOA) in silicon photonics, and believed that its technology showed great promise to drive down the cost of high-speed interconnect products.
However, the Kotura team was not able to demonstrate that silicon photonics could fulfill that potential.
While Mellanox plans to continue selling and supporting the VOA product line, it will use alternative technologies, including its own integrated circuit designs, to deliver on its roadmap for cables and transceivers at 200G data rates and beyond.
The decision is expected to have only a minor impact on Mellanox’s LinkX range of cables and transceivers for cloud, enterprise and storage applications, which includes PSM4 products based on silicon photonics.
Mellanox said it intends to retain the silicon photonics intellectual property.

https://www.fibre-systems.com/news/mellanox-ceases-1550nm-silicon-photonics-development

Today we understand why :-)

Cheers