## 2 Characteristics of Designed Silica Microsphere WGMR for Kerr-OFC
The circulating intensity can be found using the following equation [25]:  
\[I_{circ}=\frac{P_{circ}}{A_{eff}}, \tag{1}\]  
where \(P_{circ}\) is internal circulating power, and \(A_{eff}\) is the effective area of the mode area of the resonance. \(A_{eff}\) can be found by using simulations. As calculation parameters, resonator radius, refraction index, and resonance frequency at 1550 nm wavelength for fundamental mode were used. \(P_{circ}\) in the silica microsphere WGMR can be found as follows [25]:  
\[P_{circ}=P_{in}\frac{\lambda Q_{intr}}{\pi^{2}nR}\frac{K}{\left(K+1\right)^{2}}, \tag{2}\]  
where \(\lambda\) is the resonance wavelength, \(n\) is the refraction coefficient, \(R\) is the microsphere radius, \(P_{in}\) is the input power (\(P_{in}\) = 100 mW), \(K\) = \(Q_{intr}\)/\(Q_{extr}\) is the coupling parameter that shows the ratio between intrinsic and extrinsic Q-factors, and \(Q_{intr}\) is the intrinsic Q factor, which is limited by all losses defined by the resonator cavity. The coupling parameter can be estimated using transmission \(T\) at the resonance frequency [27]. \[T=\left(\frac{1-K}{1+K}\right)^{2}\text{ or }K=\frac{1\pm\sqrt{T}}{1\mp\sqrt{T}}. \tag{3}\]  
Figure 1: Illustration of 170 \(\upmu\)m SiO\({}_{2}\) microsphere resonator scans captured by SEM at 3 kV after artificial degradation by 100% humidity exposure: (**a**) 4.1 mm @\(\times\)400 times, (**b**) 4.0 mm @\(\times\)5.00 k times, (**c**) 4.0 mm @\(\times\)45.0 k times, (**d**) 2.9 mm @\(\times\)180 k times, and captured illustrations for newly fabricated 170 \(\upmu\)m SiO\({}_{2}\) microsphere: (**e**) 4.0 mm @\(\times\)300 times, (**f**) 4.0 mm @\(\times\)10.0 k times, (**g**) where evaporated silica from the arc fusion splicer discharge at 4.0 mm @\(\times\)50.0 k times, and (**h**) nanoscale particles at 4.0 mm @\(\times\)30.0 k times were observed. Several moisture and dust degradation methods of protection can be used to keep high Q factor of newly fabricated silica resonators, for instance, storage with ethanol drops or storage with dry nitrogen within hermetic enclosure boxes. The packaging technique utilized by UV-curable polymer for stabilizing both the microsphere and the tapered fiber could be preferred for long-term maintenance of silica microsphere WGMR-based Kerr-OFC light sources. While the use of a coating polymer significantly increases the stability of mechanical alignment between the microsphere and taper, accompanied by a relativity low absorption and insertion loss of polymer packaging [28]. An additional solution to keep a high Q factor for silica microresonators and taper satisfying coupling conditions and providing improved long-term frequency stability is packaging into modules that feature temperature control by integrated Peltier elements [29]. Experimental Setup of Designed Silica Microsphere WGMR-Based Kerr-OFC as A Light Source for Application in Optical Communications  
The setup used for the generation of WGMR-based Kerr-OFC is shown in Figure 2a,c. First, we prepare the tapered fiber for coupling the light into the silica microsphere. We used a non-zero dispersion-shifted fiber (NZ-DSF) patch-cable compliant with the ITU-T G.655 standard for the preparation of a tapered fiber pulling probe. In the process of the tapered fiber fabrication procedure, the tapered fiber probe was formed from two separate cut parts of an NZ-DSF compliant patch cable. The patch-cable fiber ends were cut using a fiber cleaver, cleaned, and spliced together with a commercial arc fusion splicer (Sumitomo, T-71C), ensuring a low insertion loss \(\leq\)0.01 dB. As a result, the jacket and coating of connectorized patch-cable were removed in the region of 3.8 cm, where it is intended for heat treatment. Clamps of V-grove fiber holders located on the 50 mm compact, motorized translation stages with DC servo motor actuators (Thorlabs MTS50-Z8) were used to pull the tapered fiber in both directions with a constant speed of 100 um/s (see Figure 2a,e).