Do you know what 40G Ethernet is? Do you know what a 40G optical module is? This article will introduce how the 40G optical module is developed, and how the subsequent optical modules such as 40GBASE-SR4 were born. Through the introduction of this article, you will know what 40GBASE-SR4 is, and compare other modules at the same time. What are the advantages of 40GBASE-SR4?
40G Optical Transceiver Development and Challenges
In ultra long-distance transmission, the existing optical fiber infrastructure is used to realize ultra-long-distance transmission of a simplex 40G/100G. The emergence of the 40G/100G interface provides a very good pipeline for the interconnection of core/backbone routers, but how to realize the so-called ULH (Ultra Long Haul) transmission has become an important issue in the backbone network.
In recent years, the industry has been continuously researching how to use the existing infrastructure (including optical fiber, DWDM equipment, etc. as much as possible to achieve high-speed ultra-long-distance transmission of single-wavelength 40G or even 100G.
This involves key technologies in many optical fields, including the use of more complex optical modulation techniques such as DP-OPSK (Dual Polarization Quadrature Phase Shift Keying), the use of optical amplifier EDFA, the study of higher gain and high-speed FEC algorithms, and so on. Relevant technologies have made obvious breakthroughs, and the road to commercial use of 40G Ethernet has gradually become clear.
High-speed interfaces of dedicated message processing chips, including high-speed SerDes, high-speed and large-capacity cache, etc. For 40G/100G platforms, high-speed interfaces have become one of the key technologies in chip and system design. On the new generation of high-end platforms, each slot requires 10Gbps SerDes (64/66 encoding) 60 to 80 pairs, converted to 3.125Gbps SerDes (8/10 encoding), it is as high as 240 to 320 pairs, this density is almost impossible to achieve physically, therefore, use a higher rate as much as possible Ser Des is the key to achieve a high-end platform.
In addition to SerDes, packet buffering and queue scheduling are also key technologies in implementing 40G/100G platforms. Theoretically, the incoming packets from a 100G port need one write and one read at a time, which requires a bandwidth of 200G, and the total theoretical bandwidth of three 64-bit controllers is 3*85.376=256.128G.
That is to say, at least three 64-bit DDR3 controllers are required to meet the message buffering requirements of one 100G port. Considering that the actual effective bandwidth of DDR3 will be lower (the efficiency drop is especially obvious when short packets are used), the scheduling overhead may actually require more memory controllers to implement. Such a high number of memory interfaces and bandwidth requirements are also a huge challenge for chip design itself.
What is The 40GBASE-SR4?
The 40GBASE-SR4 transceiver is terminal with a 12 core MTP/MPO male connector, which can reach up to 150m on OM4 MMF (100m on OM3). The transceiver complies with QSFP+ MSA, IEEE 802.3ba 40gbase-sr4 and 4x10gbase-sr standards. The digital diagnostic function can also be used through the I2C interface.
By optimizing the transmit and receive optical characteristics of the QSFP-40G-SR4, worry-free 4 x 10G mode operation can be achieved to prevent receiver overload or trigger unnecessary alarm thresholds on 10GBASE-SR receivers, while compatible with all standard 40GBASE-SR4 interfaces are fully interoperable.
The 4x10G connection is achieved by using an external 12-conductor parallel to a 2-conductor duplex breakout cable that connects the 40GBASE-SR4 module to the four 10GBASE-SR optical interfaces. Below is a picture of a 40GBASE-SR4 QSFP+ transceiver.
Conclusion
After this article introduces how 40G optical modules are developed and how 40GBASE-SR4 is standardized, we should choose a third-party supplier of good quality when choosing 40GBASE-SR4, such as QSFPTEK.
The QSFPTEK company is a company specializing in the production of optical modules. And related product technology companies, if you want to know more about 40GBASE-SR4, you can contact QSFPTEK customer service via sales@qsfptek.com.
