I am sending video on a singlemode fiber from building A to building B.

Question: I am sending video on a singlemode fiber from building A to building B. I would like to see if i can send two cameras back from building B to building A on the same singlemode fiber. If so what equipment will I need?

Answer: By using WDM's (Wave Division Multiplexers), you can send two different signals on the same fiber in opposite directions. WDM's are generally a 1x2 device similar to a coupler or splitter, except that it will separate and/or combine wavelengths on a single fiber. For example, if your current video system is transmitting at 1550nm, you could use a WDM at each end and a 1310nm TX and Rx for the signal in the reverse direction.