Disco, you are on fire lately, thanks for bringing these articles to our attention. This is a very big dot.

This part jumped out at me in a big way:

"Facebook has been working for the past year and a half to come up with a solution to its fiber interconnect problems, and Schmidtke says that it has chosen a single mode fiber optic cabling solution that it has worked with the industry to tweak so it can work over datacenter distances and be a lot less expensive than the longer haul single mode fiber that has currently been available for 100 Gb/sec links.

So Facebook has worked with the industry to shorten the cable links to 500 meters or less in length

And now look at this excerpt from Poet's transceiver whitepaper:

"Compared to traditional VCSEL based links, integration to realize a single chip to replace the current 4-chip solution substantially simplifies and reduces both the IC costs and the packaging cost. More importantly, the complete monolithic integration can provide up to an order of magnitude improvement in total power consumption. The speed parameters also favor higher speed performance compared to traditional VCSEL-based data link capabilities for MMF based short reach applications. Since the POET VCSEL is single mode, it is further expected that using the POET VCSEL with SMF will allow a data rate of 25Gbps per channel up to 500m."