How can I send a live video from a Raspberry pi to another Raspberry pi, using an optical fibre, not using WiFi or other wireless communications? I need to send a live video recorded by a camera, connected to a raspberry pi, to another raspberry pi board, & there shouldn’t be much time lag. My requirement is to send it through a wired medium only.
Live video shouldn't be a problem using Gstreamer and RTSP. All that is built into GST and there are quite a few tutorials out there. Wired over short ( <100 meters ) distance isn't a problem as Dark Vader mentioned - a decent length of Cat6a will handle this.
Over longer distances, or if you absolutely have to use fibre, you can look into media converters (something like this - as an example). These typically take ethernet input and provider multi-mode or single-mode fibre output. There are plenty of fast ethernet ones available that make claims of 2km to 100km (thats hundred!). If you only ever need this for a Pi you wouldn't need gigabit since the Pi cannot provide that speed anyway.
Its probably best to test the RTSP stuff over ethernet first then ramp up the distances if that provides a good enough experience before commiting to hardware solutions to the distance.