Silica micro-rod resonator-based Kerr frequency comb for high-speed short-reach optical interconnects

Conventional data center interconnects rely on power-hungry arrays of discrete wavelength laser sources. However, growing bandwidth demand severely challenges ensuring the power and spectral efficiency toward which data center interconnects tend to strive. Kerr frequency combs based on silica microresonators can replace multiple laser arrays, easing the pressure on data center interconnect infrastructure. Therefore, we experimentally demonstrate a bit rate of up to 100 Gbps/& lambda; employing 4-level pulse amplitude modulated signal transmission over a 2 km long short-reach optical interconnect that can be considered a record using any Kerr frequency comb light source, specifically based on a silica micro-rod. In addition, data transmission using the non-return to zero on-off keying modulation format is demonstrated to achieve 60 Gbps/& lambda;. The silica micro-rod resonator-based Kerr frequency comb light source generates an optical frequency comb in the optical C-band with 90 GHz spacing between optical carriers. Data transmission is supported by frequency domain pre-equalization techniques to compensate amplitude-frequency distortions and limited bandwidths of electrical system components. Additionally, achievable results are enhanced with offline digital signal processing, implementing post-equalization using feed-forward and feedback taps.

Automated summary

Conventional data center interconnects face challenges in terms of power and spectral efficiency due to growing bandwidth demand. Kerr frequency combs based on silica microresonators can alleviate this pressure by replacing multiple laser arrays. In our experimental demonstration, we achieve a record bit rate of up to 100 Gbps/λ using a silica micro-rod-based Kerr frequency comb light source for a 2 km long short-reach optical interconnect. Additionally, we demonstrate data transmission of 60 Gbps/λ using non-return to zero on-off keying modulation. The Kerr frequency comb light source based on the silica micro-rod resonator generates an optical frequency comb in the optical C-band with 90 GHz spacing between optical carriers. Frequency domain pre-equalization techniques and offline digital signal processing further enhance the achievable results.