# All-Optical Simultaneous Frequency Metamorphose Contingent on a Three Parallel SOA-MZIs Copula
## 1 Introduction  
The frequency conversion practicability of the sampling mixers plays a momentous part in systems dependent on radio frequency (RF) and millimeter-wave (MMW). Recently, sampling optoelectronic mixers have enticed great solicitude owing to their impacts of the capacious band, soft loss, and immunity to electromagnetic interference (EMI) [1], which are difficult to acquire by adopting imitative electric mixers.  
Semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) that exploits cross gain modulation (XGM) [2] and cross phase modulation (XPM) [3, 4, 5, 6] can be employed for frequency shifting in the formation of a stand-alone apparatus. SOA-MZIs provide a considerable extinction ratio (ER), low optical input power, up and down frequency mixing simultaneously, and positive conversion gains (CGs) [5, 6]. The principle of parallel SOA-MZIs that have congruous characteristics and operating points can also be adopted for frequency mixing [7, 8, 9, 10, 11] and execute simultaneously the up-conversion of many input optical signals by applying a sampling method.  
Recently, experimental and simulated considerations of frequency mixing predicated on a monocular SOA-MZI and a cascaded SOA-MZIs relation [12, 13, 14, 15] exhibited well performances through the quality and efficacy of the optical transference system. Specifically, adata signal at 0.5 GHz was sampled at target frequencies between 8.3 GHz, which was adjacent to the frequency of the sampling signal called the first harmonic, and 157 GHz, which was adjacent to the frequency of the sampling control signal entitled the tenth harmonic. The mixing gain fulfilled in this domain of target frequencies declined from 43 to 21 dB.  
In this paper, we employ a sampling SOA-MZIs system built in parallel combinations to accomplish simultaneous up mixing of three IF signals dependent on a standard modulation architecture for the first time by employing Virtual Photonics Inc. (VPI) software. The highest conversion gain (CG) is reached for optical mixed signals after photo-detection from 0.5 to 97.5 GHz associated with the fifth harmonic frequency of the sampling signal. Moreover, we examine the quality of the optical mixing system using intricate modulated signals that move orthogonal frequency division multiplexing (OFDM) data in order to identify its goodness, which to our knowledge, this work is a pioneer one. In fact, this approach is considered the first for sampling of parallel SOA-MZIs link. The stimulated and theoretical CGs, error vector magnitude (EVM), and bit error rate (BER) are determined in order to analyze the performance characterizations of the optical three parallel SOA-MZIs system. This system, which is a novel principle based on the sampling of parallel SOA-MZIs to attain simultaneous frequency shifting up to 99 GHz, is also realized as an excellent performance in comparison with the previous systems that relied on a single SOA-MZI and a cascaded SOA-MZIs link [12, 13]. The following sections of the paper are organized as follows: In Section 2, we depict the small-signal analysis of the three parallel SOA-MZIs link for the standard modulation mode. In Section 3, the operating point and physical parameters of the conducted simulations are analyzed, and the theoretical and simulated conversion gains (CGs) that have the identified values are achieved. Then, in Section 4, the simulation and theoretical outcomes for the up-conversion process to higher frequencies of intricate OFDM data by utilizing the sampling of the three parallel SOA-MZIs link against the EVM and BER parameters are presented. Finally, in Section 5, the conclusions dependent on the significant outcomes of this simulation study are presented.