Yup. Fiber optics can't feasibly be jammed. The drone is still powered by battery, but is controlled over a fiber that is spooled in the canister on the bottom.
SM fiber is dirt cheap, they don't need to wrap it in kevlar like you'd find in data centers ironically enough, it's just a strand or two of thinly jacketed single mode fiber.
Only has to survive the one flight, be light enough and long enough.
Cable is pretty much invisible to the naked eye beyond a few meters, imagine a hair made from glass.
Might be able to track it on foot by running it through your hands but that doesn't sound fun or safe for it's 40km range.
Definitely not something another fpv drone will be able to spot and follow.