How to Choose a 40G Optical Transceiver

March 11, 2022 0 By sylvia

As we know, there are many different form factors for 40G optical modules at present, including CFP, QSFP, and QSFP+. Do you know enough about these different form factors? The common QSFP+ modules are 40G QSFP+ SR4. This article will introduce these three different form factors in detail and list the parameters in detail with 40G QSFP+ SR4 as an example. Through this article, you will know more about 40GBASE-SR4.

What is a 40G CFP Optical Module? 

At early stages, 40G CFP optical transceiver is designed for 40G Ethernet link on OS2 fiber cable, be equipped with DDM function through the MDIO interface specified by CFIO MSA. 40G QSFP (Quad Small Form-factor Pluggable) optical module has four independent full-duplex transceiver channels, is a four-channel small pluggable optical module, the interface transmission rate of this four-channel can be as high as 40Gbps. The density of the QSFP optical module is 4 times that of the XFP optical module and 3 times that of the SFP+ optical module. As an optical fiber solution, it meets the needs of high-density and high-speed transmission.

What is a 40G QSFP+ Optical Module?

The “Q” of the QSFP 40G optical module stands for quad, which refers to four channels. SFP refers to a compact package.. It is designed for high-density applications such as data centers. Compared with the traditional SFP + optical module, the port density is higher and the cost of the whole system is lower. 40G QSFP+ optical module complies with SCSI, 40G Ethernet, 20G/40G Infiniband, and other standards. The 40g qsfp+ has 4 10Gbps data transmission channels. The transmission rate of 40Gbps can be realized by transmitting four channels at the same time. This optical module mainly has two interfaces: LC and MTP / MPO, which are used in single-mode applications and multi-mode applications respectively.

What is a 40GBASE-SR4 Optical Module?

The QSFP-40G-SR4 transceiver is used for 40G connectivity, it is designed with the QSFP+ form factor and the maximum transmission distance 100 meters and 150 meters via OM3 and OM4 respectively, on laser-optimized OM3 and OM4 MMF (multimode fiber). When it is applied to 40G Ethernet transmission, it can realize high-bandwidth 40G optical links on 12-core parallel fibers, linked to switches through MTP/MPO female connectors. When a 4x10G connection needs to be established, an external 8-fiber parallel to a 2-fiber duplex breakout cable (like MTP to LC breakout cable) is required.

The 40GBASE-SR4 optical module is a derivative product to meet the needs of higher-density and high-speed pluggable solutions. QSFP-40G-SR4 has 4 independent optical and optical signal channels, each channel can reach 10Gbps rate. With MTP-LC harness optic cable, 40G-10G link can be carried out. Due to its extremely low power consumption, this module is very suitable for 40G Ethernet connection transmission applications requiring high density and low power consumption, such as data center TOR, enterprise core layer to distribution layer, etc.


With the development of Ethernet, many data centers are facing increasing pressure to upgrade bandwidth. The traditional 10G SFP+ optical module can no longer meet the demand. 40G optical module can meet higher density optical data transmission. At present, many data centers have been upgraded with 40G optical modules, 40GBASE-SR4 is commonly used in the high-speed data centers. It can be used for short-range multimode transmission, accounting for a large proportion in the current market. If you want to know more about 40GBASE-SR4, If you want to know more about 40GBASE-SR4, you can contact QSFPTEK customer service via, QSFPTEK is a company specializing in the production of 40GBASE-SR4 and other optical products.