Huang Xiaoqing, dean of China Mobile Research Institute, believes that although 100G has already started, there are still four technical challenges in 100G transmission technology. The 100G failed to be widely applied at present, and the key reason is that the cost is still relatively high.
More and more high-bandwidth services, such as high-definition video, online games, and video conferencing, pose great challenges to traditional networks. As a technology to alleviate network bandwidth, 100G has become the new favorite of operators.
Since 2012, the three major operators have started the collection and testing of 100G. Wei Leping, director of the Science and Technology Committee of China Telecom Group, said that the 100G industry chain has matured, all components and subsystems have multi-factory commercial capabilities, and the market needs to have 100G system support. The backbone network will be fully transferred to the 100G-led era. Since 2013, the three major operators in China have successively launched the scaled deployment of 100G. The focus of 100G has also been transferred from the laboratory to the existing network. The 100G has already opened the commercial curtain.
4 major technical challenges
Huang Xiaoqing, dean of China Mobile Research Institute, believes that although 100G has already started, there are still four technical challenges in 100G transmission technology.
One is high power consumption. The implementation mechanism of 100G technology is complex. Optical receivers need to use coherent reception and DSP processing. The key chips are not ASIC-based, resulting in higher power consumption of the entire 100G system. When the 100G technology is commercialized on a large scale, the average power consumption per wavelength still has a problem to be solved. At present, the power consumption per wavelength is more than 200W, and the average power consumption per rack is 7000W, so three racks are needed. Obviously, the 28nm process helps reduce energy consumption, but there is currently no 28nm 100G solution. In addition, although the light energy consumption is not large, the use of next-generation optical modules will increase greatly, and it is necessary to reduce power consumption.
Second, integration, especially in the field of optical circuits and optoelectronic integration, how to add a large number of active and passive optical devices such as lasers, amplifiers, wavelength division multiplexing, transmitters/receivers, etc. to the network for high integration? Using semiconductor technology for the integration of CWDM and lasers?
The third is testing. The challenges of the 100G test include the signal quality assessment of the deployed 100G system and system maintenance after deployment. The 100G adopts polarization multiplexing, and the signal spectrum is wide. The ordinary OSDR and test instruments cannot perform real-time testing on it, and only the shutdown laser method can be used. How to implement real-time testing in the future is a topic that the industry needs to study in the future. Today’s online testing of many systems is worth studying.
The fourth is some forward-looking research. How to make the current transmission system gradually shift from traditionally oriented to network management to user-oriented management? How to allocate physical resources quickly and efficiently?
The most critical is the cost of the problem
The 100G failed to be widely applied at present, and the key reason is that the cost is still relatively high. Wang Bojian, the Solution Architect of Cisco China Telecom Operator Division, said that in the 100G era, optical modules are very expensive. The mainstream optical module CFP, the actual sales price is more than 10,000 US dollars. Jiang Bo, Ruijie Network Switch and Data Center Product Line Planning Manager, said that the cost of optical modules is 10 times higher than that of 10G optical modules. This also requires manufacturers to continue their efforts in chip integration, miniaturization of optical modules, and system design to achieve cost reduction of the overall product.
Especially in the aspect of optical module technology, the cost of this part is critical to the cost of the entire 100G system. The optical module itself has to face the challenge of controlling power consumption and improving the integration of the board, and the technical field lacks with foreign manufacturers. The strength of the competition has led to high production costs.