Differences between 10G, 25G, 40G, and 400G optical modules

Due to the continuous growth in the demand for data centers and cloud computing resources, the development of ultra-large-scale public cloud data centers has been driven. Global data traffic continues to rise, prompting the development of data centers from 100G to higher speed, larger bandwidth, and lower latency. 400G will be the direction of next-generation backbone network upgrades and new construction, and it will become an inevitable trend for data centers.

Many service providers have already started to deploy 400G network construction solutions. In the process of building a 400G network system, 400G optical modules play a vital role. So, what are 400G optical modules? What is the difference between 10G, 25G, and 40G optical modules?

What is a 400G optical module?

The 400G optical module is also called the 400G optical transceiver module, which mainly performs photoelectric conversion, converts electrical signals into optical signals at the sending end, and then transmits them through optical fibers, and then converts the optical signals into electrical signals at the receiving end. The transmission rate of 400G optical modules is 400G, which was born to adapt to the network market from 100M, 1G, 25G, 40G to 100G, 400G, and even 1T. 400G optical modules play a vital role in building a 400G network system. effect.

What are the standards and packaging forms of 400G optical modules?

At present, the 400G module standard has not been unified. The standard and package form of 400G optical module mainly include the following six.

①OSFP

The full English name of OSFP is Octal Small Formfactor Pluggable, and Octal means 8. This standard is a new interface standard and is not compatible with the existing optoelectronic interfaces. Its size is 100.4*22.58*13 mm^3, which is slightly larger than that of QSFP-DD, thus requiring a larger PCB area. The pins of its electrical interface are different from those of QSFP-DD, and there is a row at the top and bottom.

②QSFP-DD

The full name of QSFP-DD is Quad Small Form Factor Pluggable-Double Density. This solution is an extension of QSFP, adding one row to the original 4-channel interface to 8-channel, which is the so-called double density. This scheme is compatible with the QSFP scheme, which is one of the main advantages of this scheme. The original QSFP28 module can still be used, just insert another module.

③ CFP8

CFP8 is an extension of CFP4. The number of channels is increased to 8 channels, and the size is also increased accordingly, which is 40*102*9.5 mm^3. The cost of this solution is currently the highest.

④CWDM8

This standard is an extension of the CWDM4 standard, and the rate of each wavelength is 50G, and it can also achieve 400G. Four new center wavelengths have been added, namely 1351/1371/1391/1411nm. The wavelength range has become wider, the requirements for Mux/DeMux are higher, and the number of lasers has doubled. The maximum input power is 8.5dBm.

⑤CDFP

The CDFP standard was born earlier, and the third edition of the specification has been released so far. CD stands for 400 (Roman numerals). It uses 16 channels, and the single channel rate is 25G. Due to the large number of channels, the size is also relatively large.

⑥COBO

The full name of COBO is consortium for on board optics, which is to place all optical components on the PCB board. The main advantages of this solution are good heat dissipation and small size. However, since it is not hot-swappable, once a module fails, maintenance is more troublesome.

At OFC, an optical communication exhibition in 2018, both QSFP-DD and OSFP were launched by manufacturers at the exhibition. The two solutions have the most prominent advantages and are most likely to be the standard for next-generation data center 400G solutions. The standard and package form, and which solution will be used in the future will also depend on the network architecture of the new generation of cloud computing operators in the future.

What is the function of 400G optical module?

The main function of 400G optical modules is to improve data throughput and maximize the bandwidth and port density of data centers. The future trend of 400G optical modules is to achieve wide gain, low noise, miniaturization and integration, and provide high-quality optical communication modules for next-generation wireless networks and ultra-large data centers.

How many chips does a 400G optical module need?

my country is heavily dependent on the import of 400G optical module chips. From the perspective of the global optical chip industry competition pattern, my country's high-end optical chip self-sufficiency rate, which is mainly characterized by high speed, is insufficient, and the demand for related optical chips is extremely dependent on imports.

Therefore, although only one optical chip needs to be used in a 400G optical module, the cost ratio is high, and it is the crown jewel of the optical module industry value chain. In the optical module, the optical chip occupies the highest value end, and the higher the cost of the optical chip of the high-end optical module, the higher the cost. In 10G/25G optical modules, the cost of optical chips accounts for about 30%, the cost of optical chips in 40G/100G optical modules accounts for about 50%, and the cost of optical chips in 400G optical modules accounts for up to 70%.

What is the difference between 400G optical modules and 10G, 25G, 40G optical modules?

Although 10G, 25G, 40G and even 100G optical modules have become the mainstream of the market, with the continuous improvement of requirements for bandwidth, port density, and system energy consumption, 400G optical modules will further promote technology to higher-speed systems. A new stage of progress.

Compared with 10G, 25G, and 40G optical modules, the arrival of 400G optical modules will bring optical communication into a new era. Optical communication is changing from single-carrier modulation coherent detection of low-end optical modules to polarization multiplexing multi-carrier applications. Level phase modulation and array coherent detection of transitions. Photonic integration and electronic integration, ADC/DSP technology will be the key to the commercialization of 400G optical communication modules and systems. With the urgent need of Ethernet standardization, the requirement of optical parallelization will give a huge boost to photonic integration technology.

What is the market value of 400G optical modules?

As we all know, 100G technology products are mature, 400G is the current hot topic of discussion, and the industry is very concerned about the progress of 400G optical modules. Nowadays, the progress of 400G optical module research and development and mass production is also relatively satisfactory. In the current market background, the bandwidth demand of ultra-large-scale data centers is increasing, and 400G optical communication modules have become the best choice for improving system performance and reducing bandwidth costs. , and with the advent of the later 5G network, it will be another positive driving factor for the market value of 400 optical modules.