Of course, this requires that you ran your electrical in conduit instead of direct-bury, so this might or might not work for you.
I enjoy getting dirty though, so I had fun hand trenching out to my shed -- didn't run water and I'm kicking myself
But, I found out during inspection that the Canadian Electrical Code prohibits this, unless the fiber is functionally related to the power lines it is running with (section 56-200).
The explanation I received for the rule, was that someone like a telco installer could try and follow the fiber line, and find themselves in a dangerous situation (inside an electrical panel they aren't trained to handle).
I was able to get an exception since I am the only one who will ever open the cabinets/work on this fiber, since it was not the main internet feed to the house, but just to an outbuilding.
And if you're really ambitious, you can run it through oil pipelines.
One of the first nationwide VOD networks was a private one run by a big oil pipeline company in Houston. I knew someone who worked on one of its daily live news shows that was transmitted that way to energy traders and oil/gas executives in offices across North America.
They made a mint selling the excess bandwidth to television stations and networks.
Pipelines are already filled with all kinds of electronics.
https://www.slb.com/products-and-services/innovating-in-oil-...
The most common approach to your situation is point to point wireless. This can be off the shelf stuff from Ubiquiti/D-Link/Whatever, to more specialized products from Aruba, Cambium, etc. Ranges of 1Km and Speeds of 1Gbps are not out of the question at all. You do need line of sight though.
Wireless (or fiber) to link buildings is also a good approach as it eliminates electrical conductivity paths across networks for lightning strikes and power surges.