Is making LED at 10MHz blinking rate good?
Sfp will go up to 1Gbps for descent price. And you will not need to arrange fiber mechanics, instead you will use just a common lc connector. 

Upd:

https://en.m.wikipedia.org/wiki/Small_form-factor_pluggable_transceiver

So sfp is a small form factor pluggable transceiver. Maybe for optic cable or for copper cable. Probably is better than inventing a wheel. Also may be very cheap in China.