Question : Fiber Optic

I need to understand the definition of dark fiber. We have 4 buildings that we connected with fiber optic cable. We purchased the fiber, networking components, ran the fiber, own the fiber, etc.. My understanding of dark fiber is fiber that is run by companies(phone, cable, other), but not used. Then somebody comes along and leases the cable from them and uses it. With this understanding of dark fiber, our fiber would not be considered dark correct? It was dark when it was purchased and run, but is no longer? I was asked if our buildings are connected with dark fiber and I am a little confused about how to answer the question.

Thanks!

Answer : Fiber Optic

As you said, Dark Fiber link between two sites is a link either owned by you, or that is provided by a service provider with the condition that the link is dedicated to you, not passing the service providers active devices. (pure link).