Installation and Reference Guide
40G QSFP+ Modules
The 40G-QSFP-LR4-PSM-SM1310 module can be used with single-mode female MPO connectors only. The coupling
end face of the MPO connectors is the angled physical contact (APC) patch cord, of which the core wires must be
single-mode. Twelve channels can be used. Only 8 among the 12 MPO patch cords are recommended to be applied,
namely, Tx1-Tx4 and Rx1-Rx4.
Differences between the single-mode MPO and multi-mode MPO:
The MPO end face can be coupled in multiple modes. MPO connectors can be classified into PC connectors, super
physical contact (SPC) connectors, UPC connectors, and APC connectors based on the return loss. The return losses of
the PC, SPC, UPC, and APC connectors specified in industrial standards are -35 dB, -40 dB, -50 dB, and -60 dB
respectively. The end faces of the PC, SPC, and UPC connectors are all flat, and the only difference lies in the polish
quality, which results in different return losses. The end face of the APC connector is polished to have an angle of 8
degrees to reduce the return loss.
The APC end face can be connected to an APC connector only. The APC connector is usually green and the inclination of
the end face can be observed with naked eyes.
The coupling end face of the single-mode MPO is APC, as shown in Figure 5-7. The coupling end face of the multi-mode
MPO is PC or UPC, as shown in Figure 5-8.
Figure 5-7 APC
Figure 5-8 UPC
Dual-core LC connector for the 40G-QSFP-LR4-SM1310 module.
