Addressing the new challenges of the DCI market
High technological transparency with PAM4 (Pulse Amplitude Modulation)
The rising demand for higher bit rate fiber connections has been around for more than a decade, setting a bar at currently 100/200G per wavelength to become a wide-adopted standard. As the technology evolves and becomes more mature, newer concepts and improvements appear on the market. The massive increase of optical pluggable interface deployments in the Data Center field drives the need for alternative cost-effective solutions for interconnection.
The increasing disaggregation of network functions and the shift from managed optical to open line systems (OLS) brings also new plug-able concepts to the market such as non-coherent DWDM using PAM4 modulation. However the main driver of this innvovation here is a cost of one connection and a need for technology transparency across different vendors.
The variety of currently available 100G DWDM transceivers comprise coherent ACO (Analog Coherent Optics) and DCO (Digital Coherent Optics). The latter features an integrated DSP with advanced SD-FEC, HD-FEC technology. These transceivers have significant reach advantages and suit the long haul transmisson purpose best. However Data Centers are usually deployed near each other, so that the physical connections are way shorter, approx. 15-25 km and hence these connections may demand another technical and economical approach in terms of their realisation. In the meanwhile DCI interconnection has been established as an independent, rapidly growing market niche over the last decade.