We assess the reduction of intercore crosstalk (ICXT) in weakly-coupled multicore fiber bidirectional optical links provided by using mid-span isolators. By calculating the backscattered and indirect ICXTs, the crosstalk suppression is studied for several span lengths, fiber coupling coefficients and different numbers of mid-span isolators. When backscattered ICXT dominates the total ICXT, the number of mid-span isolators leading to the highest ICXT suppression is between 7 and 11, depending on the span length, for acceptable ICXT levels in optical links with spectrally efficient modulation formats. For 60 km and 80 km-long spans, the ICXT reduction reaches 2.7 and 1.3 dB, respectively. When deploying such a high number of mid-span isolators is not possible, placing only one mid-span isolator per span provides an ICXT reduction, for 60 km and 80 km-long spans, respectively, of 1.2 and 0.7 dB.

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Bidirectional transmission,Intercore crosstalk,Mid-span isolators,Weakly-coupled multicore fiber

• Engenharia Eletrotécnica, Eletrónica e Informática - Engenharia e Tecnologia