Photonic Network Communications https://doi.org/10.1007/s11107-018-0776-6 ORIGINAL PAPER 160 Gb/s photonic crystal semiconductor optical amplifier-based all-optical logic NAND gate Amer Kotb 1,2 · Kyriakos E. Zoiros 3 · Chunlei Guo 1,4 Received: 12 February 2018 / Accepted: 25 May 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract The performance of an ultra-fast all-optical logic NOT-AND gate using photonic crystal semiconductor optical amplifiers (PCSOA)-based Mach–Zehnder interferometers is numerically analysed and investigated. The dependence of the quality factor (Q-factor) on the input signals’ and PCSOA operating parameters is examined, with the impact of amplified spontaneous emission included so as to obtain realistic results. The achieved Q-factor is 18 at 160Gb/s, which is higher than when using conventional SOAs. Keywords 160 Gb/s · All-optical NOT-AND (NAND) gate · Photonic crystal semiconductor optical amplifier · Mach–Zehnder interferometer 1 Introduction In recent years, intense efforts have improved the perfor- mance and scaled the bandwidth of high capacity fibre communication networks by relying on functionalities exe- cuted entirely in the optical domain, thus obviating the complications of optoelectronic conversions [1]. All-optical logic gates (AOLGs) are key enabling modules in this context and can be implemented by exploiting the nonlin- earities that manifest inside semiconductor optical amplifiers (SOAs). Compared to other technological options, SOAs fea- ture stronger nonlinearity, smaller footprint, better power efficiency, and easier assembly into integration platforms. However, due to SOAs long response time [2–8], it is quite challenging to extend the operation speed of SOA-based logic schemes so as to conveniently keep up with mod- B Amer Kotb amer@ciomp.ac.cn 1 The Guo China-US Photonics Laboratory, Changchun Institute of Optics, Fine Mechanics, and Physics, Chinese Academy of Sciences, Changchun 130033, China 2 Department of Physics, Faculty of Science, University of Fayoum, Fayoum 63514, Egypt 3 Lightwave Communications Research Group, Department of Electrical and Computer Engineering, School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece 4 The Institute of Optics, University of Rochester, Rochester, NY 14627, USA ern single channel data rates [9–11]. On the other hand, the photonic crystal (PC) is a dielectric material, which when incorporated in photonic devices allows the latter to exhibit faster dynamic response and thus being amenable for supporting ultra-high-speed all-optical operation. Addition- ally, PCs present a reduction in absorption loss, suppression of undesirable nonlinear effects, low power consumption, and high power transmission over other nonlinear struc- tures. This means that if these advantages were combined with those of SOAs, then it would be possible to improve the performance of AOLGs at data rates beyond the lim- ited capability of SOAs. In fact, a PC waveguide in SOA is presented in [12–15], while the design of AOLGs using PCSOAs is the subject of [16,17]. However, these PCSOA- based AOLG demonstrations do not include the NOT-AND (NAND) gate, which nevertheless constitutes a universal gate and hence plays a catalytic role in accomplishing all-optical digital signal processing at both fundamental and system ori- ented level. In fact, by allowing to synthesize any Boolean function with reduced hardware complexity [18], it forms the core building block in applications such as combina- tional [19] and sequential photonic logic circuits [20], optical time division multiplexing (OTDM) packet-level synchro- nization [21], and programmable logic units [22]. Motivated by NAND’s outmost significance, in this paper we focus on the theoretical study of the performance of a PCSOA- based all-optical NAND gate. To the best of our knowledge, the implementation of the specific gate has so far not been 123