How much do you know about the 40G QSFP+ optical modules?

Infiberone managerGVIP2018/3/22 13:42:23

How much do you know about the 40G QSFP+ optical modules?


With the developing of cloud computing and big data, the network is developing to high rate and high density, and the utilization rate of virtual server is increased. In order to provide enough bandwidth for I/O (input / output), many new access switches have been developed to connect 2 or 4 port 40G Ethernet to core switches. The rapid development of interconnected data transmission is inseparable from the 40G QSFP+ optical module, because it can provide enough bandwidth to ensure that data transformation is unimpeded, so as to meet the needs of the data center and enterprise park for the network.

40G QSFP+ optical module is a compact pluggable optical module, it has four transmission channels, each channel data rate is 10Gbps. Its density is 4 times the XFP optical module and 3 times the SFP+ optical module. 40G QSFP+ is complies with SCSI, 40G Ethernet, 20G/40G infiniband standards. The interface types of this optical module are LC interface and MTP/MPO interface, it is used in single-mode applications and multi-mode applications, which greatly meets the market demand for high density and high-speed plug and pull solutions.

The advantages of the 40G QSFP+ optical module are as follows:

1. The use of semiconductor packaging technology, built-in 4 lasers, detectors, can support the needs of high density single board customers.

2, when the bandwidth needs to be increased, network operators can add new QSFP+ optical modules without interrupting the network service.

3, the power consumption is less than 3.5W, while the old CFP module is 8W.

4. The transmission distance of the client fiber transmission in the enterprise network, LAN, SAN and the telecommunication network can be as high as 10km.

Under the 40G Ethernet standard, there are three types of 40G QSFP+ optical modules, which are QSFP+ 40G SR4, QSFP+ 40G LR4, and QSFP+ 40G LR4.

40G SR4 QSFP+ optical module

40G SR4 QSFP+ optical module is often used in 40G data transmission with MPO/MTP joint, working wavelength is 850nm, generally used in multimode applications. It can support the signal transmission of about 100 meters of the OM3 jumper and about 150 meters of signal transmission of the OM4 jumper. When the signal is transmitted at the transmitter, the laser array will first convert the signal to the optical signal and send it parallel through the banded multimode fiber. When the receiver receives the signal, the photodetector array converts the parallel light signal into a parallel signal.

40G SR4 QSFP+ optical module is mainly used to realize the connection between network devices in data center. It is suitable for short distance transmission. Data center is often used to connect Ethernet switch with OM3/OM4 ribbon optical cable. It can not only make use of MTP/MPO optical fiber jumper to realize the connection between two 40G network devices, but also can be used together with MTP/MPO to LC optical fiber jumpers to realize the connection between 40G network devices and 10G network devices.

40G LR4 QSFP+ optical module

40G LR4 QSFP+ optical module is generally connected with the LC joint, and the maximum transmission distance of the single mode fiber can be 10km. The optical module has four independent transmitting and receiving optical channels. It is necessary to use MUX or DEMUX to reuse and reuse optical signals. At the receiver, four channels with a transmission rate of 10Gbps will be transmitted at the same time. When these serial data streams are passed to the laser driver, the Directly Modulated Lasers (DMLs) is used to control the wavelength. The optical signals modulated by a direct modulated laser are then multiplexed and assembled together on a single mode fiber. As soon as the receiver reaches the receiver, the transmitted signals are then decomposed into four channels with a transmission rate of 10Gbps. Then the PIN detector or the mutual resistance amplifier restores each data stream, and finally the Chiang Guang signal is sent out.

40G LR4 PSM optical module

The 40G LR4 PSM optical module is mainly designed based on the QSFP+ multisource protocol for appearance, optical / electrical connection and digital diagnostic interface. As a highly integrated 4 channel optical module, it has the advantage of higher port density, and it also saves a lot of cost for the whole system. The optical module using a parallel port technology (Parallel Single Mode PSM mode), using 4 parallel MPO/MTP interface design, can realize the effective transmission of 10000m. The working principle of 40G LR4 PSM module is the same as that of 40G SR4 QSFP+ module. It converts electrical signal to optical signal through laser array, and then converts optical signal to electrical signal by photoelectric detector array. The difference is that the 40G LR4 PSM optical module is usually connected to the single-mode ribbon optical fiber connector, that is to say, the parallel optical signal is transmitted in parallel through 8 single-mode optical fibers.


To sum up, the 40G SR4 QSFP+ optical module is suitable for short distance transmission, and is often used in the data center to connect the Ethernet switch with the OM3/OM4 ribbon cable. The 40G LR4 QSFP+ optical module and the 40G LR4 PSM optical module are suitable for long distance transmission. In comparison with the two optical modules, the 40G LR4 QSFP+ optical module is more cost-effective. Because in long distance transmission, the 40G LR4 QSFP+ optical module only needs two single mode fibers, and the 40G LR4 PSM optical module requires eight single mode fibers.

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