If you've got experience of the 880-series and no experience of fibre, consider looking at the 890 series as a starting point. It's pretty similar to the 880 series, but they have SFP ("small form-factor pluggable") interfaces, which is one of the most common optical interface kinds. You choose the SFP depending on what the other end tells you. There are many other kinds of fibre connectors but this is very common, and you can see from the way Cisco positions this product it's quite possibly suitable for your kind of situation.
EDIT: additionally it needs pointing out that even if the fibre is suitable, there might be protocol and demarcation issues.
The question to ask is: can I plug it straight into the SFP port of my router? If so, what connector type and speed? One client's ISP gave the answers "certainly" and "LC" and "SX" (short wavelength, 850 nm), you just buy those and it's hardly more tricky than copper ethernet patch cables. If you're lucky, yours will be like this.
But at other clients' sites it's more complex. I'm looking at one installation where the fibre arrives into a small ZTE termination unit ONT and then to client router over copper patch. Another has fibre into a large Fujitsu rackmount termination (over SFP), then copper to ISP router and then copper to client router. In both those cases it would not have been consistent with the ISP to plug the fibre into the client router.
I'm afraid what's going to suit you is all in the detail, but I hope this helps a little.