This article introduces 100G QSFP28 ER4 optical module

Nowadays, 100G QSFP28 optical module is popular in the optical communication industry due to its advantages of small size, low power consumption and high density. At present, there are many types of 100G QSFP28 optical modules on the market, such as 100G QSFP28 SR4 optical module, 100G QSFP28 LR4 optical module, 100G QSFP28 PSM4 optical module, 100G QSFP28 CWDM4 optical module, etc. The transmission distance ranges from 500m to 10km. However, to achieve a longer distance, the 100G QSFP28 ER4 optical module needs to be used. This article introduces the 100 GBIT/s optical module with a transmission distance of 40 km from the aspects of definition, working principle, and application.

This section describes the 100GBASE-ER4 standard

Before introducing the 100G QSFP28 ER4 optical module, let's take a look at the 100GBASE-ER4 standard. The 100GBASE-ER4 standard is defined by the IEEE 802.3BA working group. It supports DWDM technology and can transmit signals in the 1310nm wavelength range through single-mode fiber jumpers. Where "ER" stands for extend reach, 40 km transmission can be achieved by SOA amplification before the optical signal passes through the PIN photodetector.

Overview of 100G QSFP28 ER4 optical module

The 100G QSFP28 ER4 optical module complies with the QSFP MSA, IEEE 802.3ba, 100gbase-er4 Lite, and OTU4 standards. The transmission distance can reach 40km over single-mode optical fibers, supports 100G Ethernet and OTU4, and consumes 4.5W.

Working principle of the 100G QSFP28 ER4 optical module

The transmitter of 100G QSFP28 ER4 optical module works in the four LAN WDM wavelengths of 1295nm, 1300nm, 1305nm and 1310nm. Optical signals in these four bands are multiplexed by WDM and transmitted through LC duplex single-mode fiber jumper. At the receiving end, the optical signals are amplified by SOA (PIN receivers are used to convert optical signals back to electrical signals) and then decomposed into individual channels by WDM WDM multiplexers.

QSFP28 ER4 Module Working Principle.jpg

Figure 1: Working principle of QSFP28 ER4 optical module

100G QSFP28 ER4 application scheme

Whether it is enterprise network or data center, 100G direct connection or interconnection, want to achieve 40km long distance transmission, 100G QSFP28 ER4 optical module is a good choice.

Direct solution

You only need to insert two 100G QSFP28 ER4 optical modules into the QSFP28 ports of the two 100G switches and connect them with an LC duplex single-mode optical fiber jumper to achieve 100G direct connection. The maximum transmission distance can reach 40km.

QSFP28 ER4 Module Direct Connection.jpg

Figure 2:100G QSFP28 ER4 optical module used for direct connection

Interconnection scheme

The 100 GBIT/s QSFP28 ER4 optical module is used to connect data centers in different geographical locations. The 100 GBIT/s QSFP28 ER4 optical module supports high-speed remote interconnection between 100 GBIT/s data centers, which is convenient and economical. The following figure shows the data center interconnection solution using 100G QSFP28 ER4 optical module.

QSFP28 ER4 Module Data Center Interconnection.jpg

Figure 3:100G QSFP28 ER4 optical module used for data center interconnection

Answers to faQs about the 100G QSFP28 ER4 optical module

1. What are the differences between 100G QSFP28 ER4 and 100G QSFP28 ER4 Lite optical modules?

The BER requirement of the 100G QSFP28 ER4 optical module is better than that of the 1E-12 optical module without the FRONT-END error correction function of FEC. However, the existing APD technology cannot meet the sensitivity requirements of 100G QSFP28 ER4 optical module. Therefore, many optical module manufacturers in the industry have defined non-standard 100gbase-er4 Lite optical modules in the QSFP28 package with a maximum transmission distance of 40km with FEC and 30km without FEC. FS can provide the QSFP28 100G ER4 Lite optical module, which meets the Ethernet 100GBASE-ER4 Lite standard and fully meets the user's requirements for harsh environmental conditions such as temperature, humidity, and electromagnetic interference.

2. What is the difference between 100G QSFP28 ER4 optical module and 100G QSFP28 4WDM?

There are differences in their application fields. The 100G QSFP28 ER4 optical module supports dual-rate 100G Ethernet applications, while the 100G QSFP28 4WDM supports only 100G Ethernet applications. The specific similarities and differences are shown in the following table.

Type 100G QSFP28 ER4 Optical module 100G QSFP28 4WDM Optical module

Channel rate 25.78125Gbps/27.95Gbps 25.78125Gbps

Maximum transmission distance 40km 10km 20km 10km

Center wavelength

1295.56 nm

1300.05 nm

1304.58 nm

1309.14 nm

1271nm

1291nm

1311nm

1331nm

1295.56 nm

1300.05 nm

1304.58 nm

1309.14 nm

1295.56 nm

1300.05 nm

1304.58 nm

1309.14 nm

FEC Supported Or not No FEC supported (BER 1E-12) FEC supported (BER 5E-5)

Receiver SOA+PIN ROSA PIN ROSA PIN ROSA APD ROSA

Cooling requirements Cooling not cooling Cooling cooling cooling cooling

3. What is the difference between 100G QSFP28 ER4 optical module and 100G SR10 optical module?

The main differences between the 100G QSFP28 ER4 optical module and the 100G SR10 optical module lie in the transmission distance and the optical fiber jumper. The 100G QSFP28 ER4 optical module uses LC duplex single-mode optical fiber jumper to achieve 100G direct connection and interconnection. The maximum transmission distance is 40 km. The appearance of 100G QSFP28 ER4 optical module is conducive to the development of high-capacity integrated 100G optical module used in data centers and metropolitan area networks. The 100G SR10 optical module can be directly connected to the MPO/MTP-24 multi-mode optical fiber by using the MPO/MTP-24 multi-mode optical fiber jumper. The maximum transmission distance with OM3 multi-mode optical fiber is 100m, and the maximum transmission distance with OM4 multi-mode optical fiber is 50m. Mtp-lc branch fiber jumper can also be used to achieve 100G-10*10G network transmission.