Maximum achievable crosstalk isolation in full-duplex single-strand fiber-optic systems

A simple theoretical derivation of the maximum cross-talk isolation achievable in full-duplex single-strand multi-mode fiber-optic systems operating at a single wavelength is performed. For a commercial fiber of 1 km length with a total attanuation of 8 dB/km and a NA of 0.16, the measured cross-talk isolation was 42 dB for a single 130 ns, 0.9 μm pulse in agreement with the theory.