Now that we know we have to choose the best 100G optics based on our actual demand, but how? How can we choose the right one? Here is a selection guide for you.

For transmission distances between 5m and 100m, you can choose the QSFP28 SR4 optical transceiver module. It can transmit 70m using OM3 fibers or 100m using OM4 fibers.

For transmission distances between 100m to 2km, QSFP 100G PSM4 or QSFP28 CWDM4 modules would be better. The cost of QSFP28 CWDM4 is much higher than the QSFP28 PSM4. However, the QSFP28 CWDM4 requires only two single mode fibers in two-way transmission which is much less than the eight single mode fibers of QSFP28 PSM4, and the total cost of the QSFP 100G PSM4 rises very quickly. In practical applications, it is necessary to decide whether to use QSFP28 PSM4 or QSFP28 CWDM4 depending on the interconnection distance.

For transmission distance between 10km to 40km, you can consider QSFP 100G LR4 which has a maximum transmission distance of up to 10 km, or QSFP28 ER4 transceivers which can reach up to a maximum transmission distance of even further—40km.

QSFP-4X10GE-IR Transceiver

Designed with MTP interface, the parallel QSFP-4X10GE-IR transceiver offers 4 independent transmit and receive channels, each capable of 10Gbps operation. It utilizes 12-ribbon single-mode fiber cable with female MTP/MPO connector to realize 40Gbps data link with transmission distances up to 1 km.

QSFP-40G-PLRL4 Transceiver

The QSFP-40G-PLRL4 transceiver uses 12-fiber MTP interface to achieve 40Gbps parallel transmission, supporting maximum data link lengths up to 1.4 km. The cable type required for QSFP-40G-PLRL4 transceiver is an APC (angle polished connector) single-mode 12-fiber MTP cable. APC is the only available type for single-mode MTP-12 fiber.

QSFP-4X10G-LR-S Transceiver

The QSFP-4X10G-LR-S transceiver is a parallel 40Gbps QSFP+ optical module. It supports link lengths of up to 10 km on G.652 single-mode fiber. It enables high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP female connector. It can also be used in a 4x10G mode for interoperability with 10GBASE-LR interfaces up to 10 km.

When reading this, you may find that all these three types of 40G transceivers are designed with MTP interface and use parallel transmission. In parallel transmission, data signals are sent sequentially on the same channel. In addition, they all use 1310nm wavelength and can transfer data signals up to at least 1 km. What’s more, they are compatible with the Small Form Factor Pluggable Multi-Sourcing Agreement (MSA) and they support Digital optical monitoring (DOM).