Why We Need 40G
When 40G was first proposed, people were amazed at its high speed, and conservatives were noncommittal about the application prospect of 40G. With the expansion of domestic broadband services and data services and the increase of network transmission capacity, the network with higher speed and faster response become more and more urgent.
It was suggested that why not add only four 10G channels to achieve 40G capacity? In fact, the bandwidth of the core optical network must be greater than any single incoming signal. When 10G came out, the interface speed of the fastest switch or router was only 2.5G. Now that the speed of the router has caught up with and surpassed, it is time to expand the core network again.
There is a simple logic behind expanding channel bandwidth. The core should be able to package services and effectively transmit these packets in the network. If multiple data connections can be included in each wavelength, the function and profitability of the core network will be greatly improved. Therefore, as the data network equipment begins to adopt a 10G interface, the core transfer to 40G becomes very important.
Emphasize the important role of 40G because it has a wide range of applications. The 40G interface will provide high-speed interconnection functions in data centers or network pop nodes. At the same time, we will also see the wide application of the 40G system in man and long-distance trunk networks.
What part of the 40G network is going to focus on. As the network pays more and more attention to the metropolitan area, the bandwidth demand of some metropolitan area networks is likely to be equal to or even exceed the bandwidth demand of the core network. This will lead to the adoption of the 40G system in man first. However,
historically, no matter how the network business develops and how much bandwidth demand is, the core network always leads the bandwidth demand.
Key Optical Communication Products of 40G Transmission
40G QSFP+ SR4
40G QSFP+ SR4, also known as 40GBASE-SR4, is used for 40G Ethernet short-distance transmission. SR refers to short-distance transmission. QSFP+ SR4 optical module complies with IEEE 802.3ba 40GBASE-SR4 standard and adopts MPO/MTP optical fiber connector. When used with OM3 optical fiber, it can transmit 100m at most and 150m when used with OM4 optical fiber.
The QSFP-40G-SR4 optical module has independent transmitting and receiving parts, and each part has four parallel optical fibers. When the SR4 optical module is used for a 40G connection, all 8 optical fibers are required, and the optical fiber jumper with MTP/MPO12 optical fiber connector is required. Therefore, as shown in the figure below, four optical fibers in each link will be idle.
40G QSFP+ LR4
40G QSFP+ LR4 is also called 40GBASE-LR4, which is also used for 40G Ethernet transmission like 40GBASE-SR4. QSFP+ LR4 optical element complies with IEEE 802.3ba 40Gbase-lr4 standard and adopts LC duplex connector, which can transmit long-distance (LR) up to 10km on single-mode fiber. QSFP-40G-LR4 optical module adopts the same package as 40GBASE-SR4, and also provides four independent transceiver channels, each with a bandwidth of 10Gbps.
In order to transmit 4-channel signals on single-mode fiber, the 40G LR4 optical module must multiplex or demultiplex optical signals through internal MUX/demux. The working mode of 40GBASE-LR4 is shown in the figure below.
Conclusion
The application of 40G transmission is unstoppable, and the scale application is only a matter of time. With the continuous improvement and maturity of relevant technologies and devices, 40G transmission costs will be gradually reduced and will be used on a large scale. QSFPTEK provides 40G/100G optical communication relevant products such as optical transceivers, optical fiber cables, DACs, AOCs. Welcome consulting via sales@qsfptek.com.
