Typical fibre connectivity requires dual-strand fibre for two endpoints of the optical full-duplex network, with; the first one used for transmission and the second for reception.
However, this can be optimized by using single strand fibre optical transceivers that enable bi-directional full-duplex operation of transmit and receive signals over a single strand fibre by using separate wavelengths – e.g. 1310nm/1490nm or 1310/1550nm.