## 1 Introduction  
Delaying radio frequency (RF) signals using optical components has gained attention for various applications [1, 2]. One of the most promising applications is hybrid optoelectronic beamforming radar systems. In such systems, optical delay buffers can be utilized alongside electronic memory buffers, allowing processors to tunably delay linear frequency modulated (LFM) radar pulses for feeding beamforming antennas. The advantage of using optical memory buffers is their ability to add large discrete delays in steps of tens of nanoseconds, which are challenging to achieve with electronic memory due to extensive requirements. Thus, electronic processors contribute to beamforming by adding small offsets of fine-tuning delays in the order of picoseconds, while optical memory buffers provide larger offsets of coarse-tuning delays in the order of nanoseconds [3]. To effectively delay radar LFM pulses, optical memory buffers must meet certain characteristics. Specifically, they should (i) provide different delay values to increase the tuning range, (ii) introduce delays with low latency (i.e., minimal added non-functional delay), (iii) support wide bandwidth, and (iv) deliver delays with high peak sidelobe levels (PSL) of the compressed LFM pulse [4, 5, 6]. Several optical delay techniques have been reported in this research area, such as (i) passing the signal through fiber segments of different lengths [7, 8], which is challenging to scale, as each additional delay value requires an additional fiber segment, or (ii) recirculating the signal in fiber delay loops, which require a switch before the loop to prevent signal overlap, restricting the system to handling only short waveforms in time [9, 10]. An interesting optical technology that could meet the requirements for delaying LFM pulses is chirped fiber Bragg gratings (FBGs) [11]. Chirped FBGs have been used to (i) compensate for chromatic dispersion in fibers [12; 13], (ii) generate RF pulses [14; 15; 16; 17; 18], and (iii) delay signals by designing gratings to provide wavelength-dependent group delay [19; 20; 21; 22]. For example, the work in [23] demonstrated using dispersive fiber gratings to tune the delay over 100 ps in a simplified system design for true-time delay beamforming. While the work showed successful steering for the RF X-band signal, it is still important for such a system to eliminate the need for technical complexities associated with the signal-side band (SSB) modulation needed to overcome the RF power fading and demonstrate such a system while processing broadband signals with bandwidths in the GHz range. Therefore, combining different chirped FBGs in a delay system can be a solution that offers many favorable advantages, such as (i) delay range scalability, providing multiple wavelength-dependent delays in the same setup, (ii) lower latency, as generating wavelength-dependent group delays in FBGs can occur in shorter devices compared to long fiber lengths, and (iii) wide bandwidth, as tailoring the intra-channel chromatic dispersion in concatenated FBGs achieves a flat response with a large bandwidth for each delay channel. Using an optical frequency comb based on Kerr non-linearity as an optical source in various applications is another area of great interest [24; 25; 26]. A Kerr comb based on a microresonator provides multiple frequency lines in a compact footprint, replacing the need for a bank of discrete laser sources and eliminating the need for a fast-tunable laser source to extend the delay tuning range in wavelength-dependent delay systems [27; 28]. Therefore, a laudable goal would be to demonstrate an optical buffer system combining different types of chirped FBGs and a frequency comb based on Kerr non-linearity for delaying an LFM signal and providing (i) a large tunable delay range, (ii) low latency, (iii) wide bandwidth, and (iv) high PSL.