I have a Fiber link in place and would like to plug in 2 7606 routers on either end on this link.
Does the 7606 have the capability to connect to FX? If not, can I insert a PA with Fiber connectors (like an OC1)?
You sure can. You can either use GLC-FE-100FX or GLC-FE-100LX.
Here's the link of supported SFP modules (FastEthernet and GigEthernet) for the 7600 routers:
Hope this helps you.