For a longer period of time, both wired and wireless broadband access users will continue the rapid growth of HDTV, 3DTV, Internet of things, cloud computing and other emerging broadband applications, single-user bandwidth demand will increase exponentially, the transmission bandwidth will continue to grow, operators facing the situation of the bandwidth increment and income not increase, the future backbone network also faces huge long-term transmission pressure, 100G DWDM high-capacity transmissioin is an effective means to ease the pressure of the carrier transport.
100G source is 100GE business, 2010 years IEEE802.3ba 100GE complete specification, at the end of 2009, ITU-T 100GE business hosting defines an OTU4 OIF standardized business module to achieve as well as 100G interoperability even interoperable interface specification 100G-related standards have been released, the 2011 international mainstream equipment manufacturers has introduced a 100G DWDM backbone transmission solution. In order to solve the trunk transmission bandwidth pressure, the world’s leading carriers actively promote 100G commercialization process. In 2011, China Telecom started the 100G DWDM equipment research and testing, based on domestic the 100G DWDM equipment testing, is expected this year, China Telecom and China Mobile will start 100G DWDM 100G commercial curtain is about to launch the cuttent network deployment. This paper will review the status of the 100G device technology, and explore the future trends of the 100G equipment technology.
The 100G device technology status quo
The standard lag causes many 40G solutions, to seriously affect the healthy development of the 40G product chain. Benefited from the IEEE, ITU-T, OIF standards organization almost simultaneously advancing and released 100G standard the 100G market unanimously optimistic about the industry, generally considered 100G is a long-life products 10 years.
Support long-distance high-capacity transmission
100G using the revolutionary optical coherent receiver technology as well as complex electrical processing technology, the transmission performance has been a huge boost. Optical receiver chromatic dispersion (CD) tolerance TAT 5000ps/nm, polarization mode dispersion (PMD) tolerance over 90ns, the dispersion compensation unit of the fiber optic lines may be omitted, the engineering depolyment almost can not consider the chromatic dispersion of the optical fiber and polarization mode dispersion, CD and PMD 10G 40G DWDM long haul transmission systems a key limiting factor in large-scale commmercial the 100G DWDM equipment can simplify the engineering design and operation and maintenance.
10G/40G DWDM systems with about 7% redundant hard decision error correcting codec (HD-FEC), the commercial limit of the error correction capability of about 4E-3, using the redundancy of approximately 20% HD-FEC error correctioncapacity limit of up to 8E-3. The world’s leading equipment manufacturers 100G DWDM system uses advanced soft decision forward error correction (SD-FEC) technology, error correction capability close to 2E-2, is almost better than the 7% redundant HD-FEC an order of magnitude, the system OSNR tolerance about 2dB corresponding transmission capacity is increased by approximately 60%, radio relay transmission distance of more than 1500km (20 × 22dB), the transmission capacity of close to 10G DWDM system.
The 100G device technology trends in the evolution
Broadband operators in order to solve the backbone transmission bandwidth pressure is actively advancing the 100G commercial test equipment and distribution, and the accumulation of large-scale commercial 100G equipment experience, 100G equipment can basically meet the requirements of commercial deployment, but shipped in transmission capacity, power consumption of the device, the device peacekeeping capacity there is further room for improvement.
Further enhance the technical performance of the equipment
100G HD-FEC system transmission capacity is not strong, especially in the fiber link large attenuation long span, radio relay transmission distance is also in the 300-400km vast powers can not be effectively covered SD-FEC 100G long-distance transmission system must support the commercial technology.
100G system critical integrated high-speed ADC + and coherent processing the algorithm + SD-FEC ASIC chip continues to improve. Add new functional modules to optimize the efficiency of the coherent processing algorithms to improve performance and reduce chip scale; addition needed to better meet the demand for engineering applications, such as improving the algorithm to shorten business protection switching time and so on.
Still further enhance the integration of optical devices. Existing PM-QPSK integrated optical modulator and optical demodulator, the next transmitting end the drive may be further integrated with the optical modulator, the optical receiving end is an optical component, so that the integration and performance may be raised. Improve the 100G line side module design of high-speed circuits, power supply, etc., to improve the receiver OSNR tolerance.
Reduce the power consumption of the key devices
Current large-scale commercial 10G/40G equipment, the power dissipation in the core optical module unit area 1-1.5W/inch2, 100G the client side CFP module power consumption about 2W/inch2 more than 100G line side MSA 168pin module power consumption 3W /inch2. Power consumption big is not only a waste of energy, and need a larger radiator, larger fan, reduce the level of integration of the device, chip die temperature is too high will seriously affect the life and reliability of the equipment, so the equipment and reducing consumption is 100G must further resolve the problem.
The 100G coherent processing core includes high-speed ADC and DSP ASIC chip is the most advanced 40nm process, expected in the foreseeable future by the optimization algorithm to reduce the number of logical units to reduce power consumption.
To improve the 100G system equipment testing, monitoring, operation and maintenance
As optical communication system from low-speed to high-speed evolution of testing means should become better and better, the reality is due to improvement of the signal rate test greatly increase the difficulty of the 100G test methods/ standards not yet drafted, the new test instrumentation is not timely follow-up, mainly manifested in:
a. 100G transmitter, receiver indicators the lack of standards and instrumentation;
b. Laboratory lack 100G jitter test instrument;
c. the 100G OTN meter can not verify that the error correction capability of the new FEC coding;
d. work ROMS 100G of OSNR not effectively monitor and so on.
100G as the generation of long-life products, the perfect test of equipment and means of operation and maintenance monitoring is a problem to be solved in the future.Through the joint efforts of the optical communications sector, 100G DWDM technology has been basically mature, mainstream optical network equipment manufacturers have launched a timely 100G long haul optical transmission solutions, domestic and foreign carriers have started the pace of commercial test, we will usher in the era of 100G DWDM.
The the 100G DWDM equipment will start large-scale commercial future 100G equipment in system performance, power consumption and test operation and maintenance of technical means to further improve and better meet the need for operators to lower TCO.