Today’s metro environment is one of the most demanding in the entire network
Service providers and enterprises are continually being challenged to transport more data while at the same time reduce costs. After all, it is in the metro that optical networking’s most critical, bandwidth-intensive applications – residential broadband, business Ethernet, mobile backhaul and data-center connectivity – all converge.
There Is No One Size Fits All
100G technology has been elected to address the challenge of transporting enormous amounts of data and add scalability to optical networks. Clearly, 100G has rapidly matured. The time between early hero experiments and commercial product realization has been remarkably short. One factor accelerating the 100G development cycle has been early consensus across the industry on how 100G should be tackled. The OIF’s recommendation of DP-QPSK modulation for long haul systems allowed the component industry to focus its efforts into one direction. In addition, the IEEE released standards for client interfaces up to 40km, including a four-lane approach with 25G per serial channel.
No standards group, however, seemed to pay much attention to the metro segment, which comprises distances between 25km and 500km. 100G coherent solutions have great spectral efficiency, but they score very poorly in terms of space and power consumption, especially when compared to the 10x10G channels they seek to replace. This is not a temporary design flaw of early implementations but rather inherent to the technology itself. Coherent receiver technology is complex, including a lot of signal processing, which consumes significant amounts of power and generates a lot of heat.
Secondly, the cost aspect: 100G coherent solutions are certainly well on their way to move downward on the cost curve – but so are existing 10G solutions. As always, the industry is aiming at a moving target. While volumes for 100G coherent technology are going up helping to drive the cost curve down, the gap to 10x10G solutions will remain significant for quite some time.
Driving New 100G-Efficiencies
These drivers illuminated the market opportunity for lower-cost, direct detection 100G designs for the metro, and, indeed, solutions have quickly emerged. Direct detection 100G solutions are cost competitive with established 10x10G systems from day one. ADVA Optical Networking’s efficient 100G Metro solution is the most effective way to simply transport data traffic in metro and enterprise applications today. It is fully integrated into the FSP 3000 platform and utilizes four DWDM wavelengths with 28Gbit/s capacity per wavelength to support data transmission over distances up to 500km. Its state-of-the-art design offers powerful forward error correction options supporting effective link design.
Figure 1 illustrates how the FSP 3000 100G Metro solution optimizes 100G transmission over typical metro and regional network distances. Lowest cost-per-bit transmission is achieved through deployment of non-coherent direct detection. Without the use of inline amplification or passive dispersion compensation, 125km error-free performance is achieved. Without passive dispersion compensation, network operators can utilize lower cost and single-stage EDFA amplification at the terminal end points. When applying dual-stage Raman/EDFA amplifiers, the achievable single-span reach is extended to 200km, enough reach for most metro application.
Efficiency Comes as Standard
Optical networking is not a one-size-fits-all, commodity technology space. ADVA Optical Networking’s 100G Metro is the most effective way to simply transport data in metro and enterprise applications. Its compact design provides industry-leading space efficiency, its low power consumption and minimum heat dissipation saves operational cost and its ultra-low latency design makes it ideal for high-frequency trading applications. 100G Metro: The lowest costper-bit 100G transport available today.
Figure 2 shows ADVA Optical Networking’s implementation of a 100G Metro multiplex-transponder for the FSP 3000 scalable optical transport solution. While enabling maximum 100G efficiency over metro distances, a complementary coherent 100G implementation provides scalability also for long distances.
Michael Ritter, ADVA Optical Networking