More specifically, the WGMR-based Kerr-OFC comb generators physically realized on silica microsphere demonstrate [9] a new concept able to provide an attractive solution to intra-DCIs due to low costs and energy consumption. The data centers (DCs) are the foundation of Internet applications such as cloud computing, where Big Data storage and large-scale high-performance computing (HPC) take place. The intra-DCI devices require not only large capacity but, most importantly, high scalability and low energy consumption. Therefore, these requirements require new transmission technologies for short-reach communications [10; 11]. It can provide a lower energy consumption while ensuring improved spectral efficiency and a stable frequency spacing between OFC lines (carriers) thanks to the sustained strong phase relation between them [9; 12; 13]. OFCs have various realizations; among them, the realization by four-wave mixing (FWM) in highly nonlinear optical fiber (HNLF) [13], electro-optic phase modulation of a laser using, e.g., cascaded phase and amplitude modulators [1; 14], chip-based mode-locked laser (MLL) combs [13], and silicon microroring resonators [13; 15]. Potentially cost-effective solutions for the realization of data transmission in optical WDM networks are OFC generation in silica whispering gallery mode resonator-microspheres manufactured from melted telecom fiber, e.g., from Corning SMF 28e (ITU-T G.652) [9; 12; 14], which is realized as the pumping of a high-quality (high Q factor) optical resonator with Kerr nonlinearity using a single continuous-wave (CW) laser. When optimal conditions are met, the intracavity pump photons are redistributed via the FWM to the neighboring cavity modes, thereby creating the so-called Kerr OFC. The exciting pump signal is launched into the Kerr-OFC resonator via a tapered fiber, and an OFC is generated at the output of this taper. In addition to being energy-efficient, conceptually simple and structurally robust Kerr comb generators are very compact devices (to micrometric size) that can be integrated on a chip [16; 17]. Kerr microresonator OFCs can achieve bandwidths of hundreds of nanometers covering different (e.g., E., S., C., and L-band) telecommunication bands (according to ITU-T G. 694.1 recommendation) [18; 19]. Considering the findings of our previous works [9; 12; 20; 21], here, we propose a silica microsphere WGMR-based Kerr-OFC as a light source operating in the C-band (1530-1565 nm) and having 400 GHz spaced comb lines. These comb lines are subsequently used as optical carriers for the data transmission using the intensity modulation direct detection (IM/DD). Data rates up to 50 Gbps/\(\lambda\) are employed in combination with the non-return to zero (NRZ) on-off keying (OOK) format for the transmission over a 2 km short fiber-optic link consisting of the standard ITU-T G.652 single-mode fiber. The aforementioned IM/DD signal format is chosen as it still dominates in short-reach optical interconnects due to its simplicity. Digital equalization techniques shown in our previous works [22], such as a linear equalizer with feed-forward (FF) and feedback (FB) taps, can improve the signal quality due to different system distortions, mainly caused by limited channel bandwidth and nonlinearities during the optical to electrical (O/E) and electrical to optical (E/O) conversions and the link induced inter-symbol interference (ISI). Therefore, we apply the use of the symbol-spaced adaptive decision-feedback equalizer (DFE) implemented at the receiver part to improve the pre-FEC bitrate and to achieve higher data rates in DCI with the optical carriers generated by the developed silica microsphere WGMR-based Kerr-OFC. The rest of the paper is structured as follows. Section 2 describes the characteristics of the designed silica microsphere and shows the deterioration of its Q factor with time. Section 3 presents the experimental setup of the WGMR-based Kerr-OFC light source operating in the C-band and used for the generation of 400 GHz spaced optical carriers.