## 6 Discussion and Conclusions  
In conclusion, we have demonstrated delaying a radio frequency-linear frequency-modulated (LFM) wide-band pulse of 1-GHz bandwidth by modulating the LFM pulse on optical carriers from a Kerr comb and sending the modulated carriers through an optical memory buffer system with the concatenation of off-the-shelf linearly chirped fiber Bragg grating (LC-FBG) and chirped-and-sampled FBG (CS-FBG). Potential advantages of using our structure include (i) a larger tunable delay range, (ii) low latency, (iii) wide bandwidth, and (iv) high PSL. Figure 12: The results when delaying a 10 GHz bandwidth LFM pulse at a center frequency of 5 GHz. (**a**) The captured LFM pulse in the time domain. (**b**) The captured LFM pulse in the frequency domain. (**c**) The back-to-back (i.e., ideal) LFM pulse of \(B\) = 10 GHz at \(f_{0}\) = 5 GHz after compression, showing a maximum PSL of 42.68 dB. (**d**) The PSL for the four versions of the LFM pulse in the optical delay buffer after compression when the FBGs are bypassed. (**e**) The PSL for the four versions of the LFM pulse after compression and after using the equalization filter \(H(f)\). (**f**) After compression, the PSL for the four delayed versions of the LFM pulse when inserting the FBGs for the delay and using the equalization filter \(H(f)\). Our measurements show that our proposed system can potentially (i) provide a delay range of 76 ns with 100 steps, (ii) delay the signal with a latency of <5 ns if carefully packaged, (iii) delay the signals with bandwidth up to \(\pm\)20 GHz, and (iv) achieve PSL values of 34.43-35.45 dB. When we analyze the system's performance when replacing the Kerr comb source with separate lasers, the results show that independent laser sources demonstrate better PSL performance, which may be attributed to the higher emitted power per carrier compared to the comb, the higher OSNR per carrier, and the smaller number of carriers that become boosted in the 1.2 m amplifier. Here, we note that the power of the Kerr comb frequency lines and the quality of OSNR depend on several factors, including the power level of the pump laser and its carrier-to-noise ratio [28]. On the other hand, although independent laser sources show better performance, using these may not be considered a scalable solution, as they require independent packaging and separate controllers for each laser. Therefore, we believe the performance of the optical buffer using the Kerr comb should be improved in the future by (i) aligning the Kerr comb and the FBGs spectra by redesigning the ring resonator to match the FBGs or vice versa, (ii) optimizing the generation of the Kerr comb with higher OSNR and power levels, and (iii) stabilizing the temperature of the Kerr comb source for better frequency/phase stability. For example, aligning the Kerr comb to the FBG can be achieved in the design and fabrication phase by tuning the microresonator's physical dimensions and its dispersion properties [33; 34]. In addition, after the fabrication, one could slightly tune the Kerr comb FSR by implementing external thermal tuning or mechanical stress [35; 36]. Also, the mechanical and thermal approaches may tune the FBGs to align with the generated comb as previously reported in [37; 38]. Regarding the Kerr comb power level and its OSNR, one should consider maximizing the input coupled power of the device [33] and using a low noise amplifier right after the device to increase the carrier's power levels. Although we did not observe significant effects of the temperature variation on the comb generation in the lab environment, it is essential to note that severe variation may lead the microresonator to lose its soliton state or slightly induce frequency shift, leading the carriers to lose the alignment with the center of the FBGs which impacts the RF channel bandwidth magnitude response.