DCI systems with ultra-low loss and low dispersion fiber

Exponential growth of Internet traffic demands data center interconnect (DCI) systems to provide 400 Gb/s and higher per wavelength capacity under tight power consumption limitations for optical transceivers. We investigate the potential advantages of applying ultra-low loss and low dispersion fibers in DCI systems. Link optical signal to noise ratio (OSNR) and capacity analysis shows that ultra-low loss fiber (0.16 dB/km) provides significantly higher data capacity as compared with regular single-mode fiber (0.2 dB/km) for 80 km long DCI links. Also, the lower fiber attenuation reduces the required transceiver output power by 10 dB to achieve the same data capacity for 100 km DCI links. This implies substantial simplification in optical transceiver design. Digital chromatic dispersion compensation (CDC) is one of the major power consumers in optical transceivers. Our analysis shows that low dispersion fiber (4 ps/(nm·km)) reduces CDC computational complexity by 20% to 71% for different DCI link lengths versus regular single-mode fiber, indicating significant reduction in power consumption. Moreover, employing the CDC capability of the built-in adaptive filter in coherent receiver digital signal processing (DSP), the digital CDC unit could be completely removed using low dispersion fibers in DCI systems. Finally, we performed Monte-Carlo simulations of DCI links with different fiber types and confirmed the benefits of ultra-low loss and low dispersion fibers.