SFP vs. SFP+

[Jason Lixfeld]

I was asked today what the difference between SFP and SFP+ is.  I did really 
know, so I looked it up and it seems that the SFP spec provides capabilities 
for data rates up to 4.25Gb/s, whereas SFP+ supports up to 10Gb/s.  Naturally, 
this made me wonder whether or not an optic that supported 10GbE always 
conformed to the SFP+ standard inherently, or if there are cases where a 10GbE 
optic might only support the SFP standard, thus having a 4.25Gb/s bottleneck.