Q:

Maximum speed of data transmission

All major data carriers these days use fiber optic links these days. And data transmission occurs at the speed of light, is that correct?
If data transmission does indeed occur at the speed of light, is it also correct to assume that data transmission will never ever be faster?
Update:
I have posted another question. I have realized due to my lack of knowledge regarding these concepts, I have posted the wrong question. Thank you for your responses. They've been really intriguing. 
Other question:
Is minimum latency fixed by the speed of light?

A:

The individual states of the light (on/off) are at the speed of light to the other end the line, however data transmission is far far slower.
You have the switching times on the components turning on and off the light, speed of connectivity between the computer and these components which is think is the main thing that determines achievable speeds on fiber. Also the overhead of the protocol 

