Things to Know About 40G QSFP+ Module

What is 40G QSFP+ Module

40G optical module refers to an optical module with a transmission rate of 40Gbps, and its common form factor is QSFP+. It is derived to meet the needs of higher-density high-speed pluggable solutions. There are four mutually independent transmitting and receiving optical signal channels, and the transmission rate of each channel is 10G respectively.

The 40G optical module can provide high-density and low-power 40G Ethernet high-speed interconnection for data centers, high-performance computing networks, and telecom operators. However, the 40G product layout is also a transitional product, completing the transition from 10G to 100G.

40G QSFP+ LR4 Fiber Optic Transceiver

40G QSFP+ LR4 optical module is generally used together with LC single-mode optical fiber jumper, supporting a maximum transmission distance of 10km, and it has four data channels, which will transmit data at the same time. The 40G LR4 QSFP+ optical module has the advantages of high density, low cost, high speed, large capacity, and low power consumption.

Working principle of 40G QSFP+ LR4 optical module: the laser driver controls the arrival wavelength, and the optical signal is combined together for transmission through the multiplexer. When reaching the receiving end, these transmitted signals are decomposed into four channels with a transmission rate of 10Gbps by the demultiplexer, and then the PIN detector or mutual resistance amplifier restores the data stream and then transmits the optical signal.

40G QSFP+ SR4 Fiber Optic Transceiver

40G QSFP+ SR4 optical module is often used with MPO/MTP interface in 40G data transmission. It has four full-duplex channels and is also transmitted through four channels. The transmission rate is the same as that of LR4. The difference is that the 40G QSFP+ SR4 optical module is often used with multimode optical fiber, and the maximum transmission distance is 150m.

40G QSFP+ PSM4 Fiber Optic Transceiver

40G QSFP+ PSM4 optical module adopts MPO interface, which is transmitted in parallel through 4 receiving and 4 transmitting channels, and the farthest transmission distance is 10km. Among many 40G optical modules, QSFP+ SR4 and eSR4 also have MPO interfaces, but their transmission distance is relatively short. In the MPO/MTP cabling system, the 40G QSFP+ PSM4 optical module can make up for the defect that the transmission distance of the other two modules is not long enough.

Although the transmission distance of 40G LR4 and 40G psm4 optical modules is 10km, their manufacturing processes are very different, mainly in the following aspects.

1. The working wavelength of 40G PSM4 is 1310nm, using parallel transmission mode, while 40g LR4 combines CWDM-Demux/Mux technology in TOSA and ROSA respectively, and the working wavel

engths are 1270nm, 1290nm, 1310nm, and 1330nm.

2. 40G PSM4 is an MPO connector, while 40g LR4 is a dual LC connector;

3. 40g PSM4 adopts COB packaging process, while 40G LR4 adopts 4-channel integrated airtight butterfly packaging process.

With the increasing maturity of 40G optical modules, AOC active optical cable, and DAC high-speed cable products, functional design is no longer the main selling point of the industry, but cost performance and reliability. In medium and long-distance MPO/MTP cabling. QSFPTEK 40G PSM4 will become the preferred solution for customers with the advantages of high-cost performance and high reliability.

40G QSFP+ BiDi Fiber Optic Transceiver

The connector type of the QSFP-40G-SR-BD optical module is LC. When used with OM3 optical fiber jumper, the transmission distance can be up to 100m, and when used with OM4 optical fiber jumper, the transmission distance can be up to 150m. 

QSFP-40G-SR-BD optical module can use multimode OM3 duplex LC optical fiber jumper in 10G cabling system to quickly build a 40G network without adding an optical fiber adapter box.


The above mentioned has introduced what is 40G QSFP+ optical module and introduce 4 types most common and  popular 40G QSFP+ transceivers, including 40G QSFP+ SR4, 40G QSFP+ LR4, 40G QSFP+ PSM4 and 40G QSFP+ BiDi optical transceiver. Whether you are looking for various types of 40G QSFP+ fiber optic transceiver or 40G QSFP+ DAC cables and AOC cables, you can find them at QSFPTEK. QSFPTEK is an original brand of fiber optic transceiver factory outlet that serves SMB users. Customer experience representatives and tech support are available round-the-clock to receive your orders and inquiries at [email protected]

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