## 1 Introduction  
All-optical Wavelength Conversion (WC) and regeneration modules have been widely studied in the past two decades, having produced a large variety of principles, techniques and devices [1; 2; 3; 4; 5; 6; 7]. Semiconductor Optical Amplifier (SOA)-based devices have been a major class of widely used high-performance WC and regeneration modules, offering high-speed WC in different alternative configurations [8; 9; 10; 11] and often deployed as highly compact integrated circuits. With SOA gain recovery time having been identified as the main line-rate limiting factor, the SOA gain dynamics have favored the use of Return to Zero (RZ) pulse formats in higher data-rate applications, reporting remarkable achievements in WC and regeneration layouts for RZ formatted data traffic with up to 320 Gb/s operational speed [12; 13; 14; 15; 16; 17]. Nonetheless, with Non-Return to Zero (NRZ) data formats appearing as the clearly preferred modulation format choice over RZ pulses, research shifted towards SOA-based WC elements that could offer the necessary functionality even with NRZ data pulses at high data-rates [18; 19; 20; 21]. Within this context, the differentially-biased SOA-Mach Zehnder Interferometer (MZI) scheme has probably prevailed as the highest-speed performing SOA-based WC for NRZ data, offering the best quality WC and regeneration characteristics up to 40 Gb/s, [21] and the highest possible cascadability potential [22]. However, when burst-mode traffic operation is targeted where data packets might have propagated through different fiber segments experiencing different losses and as such arriving with intense power fluctuations at the WC stage, wavelength conversion has to be preferably accompanied with power equalization capabilities on a per packet basis in order to ensure successful propagation of the wavelength converted signal into the next network segment. Although a large variety of burst-mode, regenerative, SOA-based WC schemes have already been proposed [23; 24; 25; 26; 27; 28; 29], most of them have been able to yield successful operation only with RZ data formats when linerales higher than 10 Gb/s are targeted [23; 24; 25]. When NRZ burst-mode operation is required, typically being the case in reach extender applications for Passive Optical Network (PON) uplink transmission or 5G digital fronthaul architectures [30], SOA-based WC schemes have been restricted to 10 Gb/s operational data-rates [26; 27; 28; 29]. In this paper, we experimentally demonstrate a new SOA-MZI WC scheme that can provide burst-mode WC operation at up to 20 Gb/s linerales even for NRZ data packets, using a single SOA-MZI device in a modified, differentially-biased, architectural layout where both SOAs are forced to operate in their deeply saturated regime [21; 31]. Combining the high-quality WC characteristics of the differentially-biased SOA-MZI scheme with the clipping properties of the SOA-MZI non-linear transfer function emerging in the deeply saturated semiconductor region, wavelength conversion can be accompanied with strong power equalization capabilities in a single device, decreasing the number of required active elements by 50% compared to state-of-the-art NRZ Burst-Mode Wavelength Converters (BMWCs) [29]. Extending our recent work on the proof-of-principle experimental demonstration at 10 Gb/s [32], the burst-mode WC credentials of the proposed deeply saturated, differentially-biased, SOA-MZI are experimentally validated both with 10 Gb/s and 20 Gb/s NRZ burst-mode packets as well as with burst-mode traffic originating after having been transmitted in 25 km dispersion uncompensated fiber links. Successful burst-mode WC operation has been obtained both at 10 Gb/s and 20 Gb/s for a loud/soft ratio of up to 9 dB and 5 dB, respectively, revealing negative power penalties of 6.1 dB and 3.51 dB at a \(10^{-9}\) error-rate, respectively.