No, you are likely looking at an ONT (optical network terminal), and it is not a router. Even with a port that accepts the fiber (sfp or sfp+ for 10g) on your equipment, the OLT (optical line terminal) likely will not provide you with service.
If you were to match the wavelengths the ISP is using you are likely to become a “rogue” on their PON that can knock out service for other customers that share the same passive network as you.
I make assumptions about you being on PON since you say AT&T, generally all I have ever seen from them are passive networks (one fiber with splitters for 1 port to many customers) unless you are paying extra for “dedicated” ($$$$$) internet.
If they are using a ONT with an “RG” (residential gateway) which is the typical “all in one” you can request the gateway service can be removed and replaced with a layer 2 bridge, where you’re router/firewall gets the “external” addressing and there is nothing being done by the ISP equipment other than sending you traffic and OAM (operations, administration, and maintenance; usually check or alert for light levels, software status, if a part of the ONT fails etc).
Verizon and ATT just rebrand nokia ONTs and roll some of their own software that is mostly enhanced or changed encryption at L1. Can’t speak for Comcast, I only know about the other two as I’m in a smaller ISP that competes with them.
They use have L2 onts that don’t have any gateway functions, just fiber to ethernet with some extra overhead to monitor the connection between the hose and shelf.
The ONT-on-a-stick units do the same thing, just a more compact and expensive interface that doesn’t have great support, unless comcast or running all home run fibers where they can just provide a straight SFP instead of doing any optical splitting.