MPO to MPO 8 Fibers – The MPO-8 supports up to four duplex channels, and is used in the QSFP transceivers that utilize the 8 fibers to provide four lanes per MPO port. The MPO-8 interface is not strictly a standards recognized infrastructure interface. It is an application that happens to use 8 of the 12 fiber positions of the industry standard MPO-12. The QSFP application uses the outer 4 fiber locations (1-4 and 8-12) of the MPO-12 connector with 4 fibers used to transmit and 4 fibers used to receive. A QSFP transceiver does not use the center 4 fiber positions in the MPO-12 connector. While a standard MPO-12 cable will fully support this application, leaving fibers unused is not desirable. For this reason,cables and connectors can be constructed with MPO-12 connectors simply not providing or terminating the center four fibers. Most commonly used to establish 40G (40GBASE-SR4) links in between two QSFP+ transceivers. Additional applications include creating back-end trunk connections. Although higher density 12 fiber connectors are preferred.
