Short answer: Usually yes, you use them in pairs, but the “pair” can be a media converter on one end and a fiber switch (or SFP in a switch) on the other, as long as both sides speak the same speed, wavelength, and optical mode. A dual fiber system uses two separate fibers: one for transmitting (Tx) and one for receiving (Rx) signals. In DWDM implementations, each direction of communication occupies a dedicated fiber, improving the stability of the transmission. They are easier to set up and give steady communication. Pick single fiber transceivers if space or fibers are limited. Dual Fiber SFP vs Simplex SFP.