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. You must deploy A/B ends as a matched pair. For example: End A: TX 1310 nm, RX 1550 nmEnd B: TX 1550 nm, RX 1310 nm Other BiDi pairs exist (e. The key is opposite directions use opposite wavelengths, so A must face B—AA or BB will not work. Since fiber optic links require a two-way - or duplex - connection, there is potential for errors in installation by connecting transmitter to transmitter or. Fiber polarity is the direction that light signals travel from one end of a fiber optic cable (link) to the other. Although it may seem obvious, fiber optic polarity is a frequent source of confusion and. Enables full-duplex communication over dual fibers or bidirectional (BIDI) transmission over a single fiber using different wavelengths. This increases the risk of signal weakening and errors over long distances. I've seen people use a single-mode.