Not just that but your average russian or ukrainian used expendable munition UAV that uses a singlemode fiber spool uses the cheapest and most mundane of fiber transceivers. There's no requirement for data rates above 1 Gbps, so ordinary SFP optics (not SFP+ or anything) are used, and the distances involved means it works fine with a extended range 1550nm to 1610nm reach thing that can nominally handle 40 to 80 km of fiber.

When I say data rates are way below 1 Gbps, it's because commonly you've got two things going on, a UART serial bridge from operator to flight controller board (same idea as what is implemented in RF with ExpressLRS, TBS Crossfire or similar), this is at most a Mbps or two. Then a possible live video feed over IP which will be easily under 50 Mbps.

The only thing a little bit out of the ordinary about them is that they're often bidirectional single strand optics with the prism built in, and tx/rx on different wavelengths (like 1550 and 1570, or 1550 and 1610, or whatever). Basically same thing that somebody lighting a very low cost metro dark fiber circuit might do to use only 1 strand for a gigabit or 10 Gbps link.

You can get a pretty good 1080p60 video at only 6mbps. Depends on how well the sender is encoding I guess, but it shouldn't be too much more than that.