## 4 Simulation Results and Discussion
### Impact of Input Noise
This indicates that the system is more sensitive to changes in OSNR under low OSNR conditions, and increasing OSNR can significantly reduce the amplitude fluctuation of logic \"1\". The two curves for 192.8 THz and 193.4 THz nearly overlap, indicating that the system's response to input OSNR in terms of AM is highly similar at these two frequencies. In Figure 12b, the output SNR increases as the input OSNR increases at both 192.8 THz and 193.4 THz. This indicates that the higher the quality of the input signal, the higher the quality of the output signal. These two figures are very similar in trend and conclusion, further verifying the consistency and stability of the system's response to input OSNR at 192.8 THz and 193.4 THz. According to Figures 10-12, we can conclude that our proposed all-optical pattern recognition system exhibits stable performance when the input frequencies are 192.8 THz and 193.4 THz at 100 Gbps. Although input noise is inevitable during signal transmission, there are two solutions that can be incorporated into our system design to reduce the influence of noise. Firstly, the regenerator in the recirculating loop can be further improved. It is mainly designed to achieve frequency conversion in the proposed pattern recognition system. However, it can be redesigned to achieve not only frequency conversion, but also suppressing the accumulated distortion and noise during transmission. There are many works that focus on all-optical frequency conversion and all-optical regeneration [29; 30; 31]. They can be achieved by cross-gain modulation (XGM), XPM, and FWM, and have been successfully tested in different nonlinear media. Secondly, an additional noise compression structure can be designed and placed in the recirculating loop to reduce the accumulation of noise caused by multiple loops. We propose a cascaded noise suppression structure based on FWM to improve the output performance of the pattern recognition system for OOK signals [32]. This structure helps to separate noise from signals by generating a step-shaped power transmission curve. The simulation results show that the proposed structure can effectively reduce errors. In future work, we will verify the effectiveness and performance of these two solutions. We hope to further improve the proposed all-optical pattern recognition system, and provide a more secure and reliable solution for future optical networks. In the simulation, only the impact of input noise is considered. However, in practical optical systems, the sources and effects of noise are far more complex. The following specific noise parameters can be integrated into future research: (1) Amplified spontaneous emission (ASE) noise. ASE noise generated by optical amplifiers is a critical factor in  
\[ER(dB)=10\log\left(\frac{P_{\min}^{1}}{P_{\max}^{0}}\right) \tag{11}\]2 Output performances of (**a**) AM; and (**b**) SNR under different input OSNRs. fiber transmission systems. It degrades the OSNR and impacts output performance. We will model the generation and propagation of ASE noise in detail and analyze its specific impact on the output quality. (2) Nonlinear effect-induced noise. In HNLF, nonlinear effects such as XPM, while enabling signal reloading and logic operation, may also introduce additional noise. We will investigate the origin and characteristics of such nonlinear noise and explore parameter optimization to mitigate its impact. (3) Fiber loss and dispersion-induced noise. Fiber attenuation reduces signal power, while dispersion causes pulse broadening and distortion, both degrading signal integrity. We will quantify the impact of fiber loss and dispersion on system performance and explore compensation techniques to improve signal quality. (4) Phase noise. Phase noise arises from fluctuations in signal phase due to environmental factors (e.g., temperature variations, mechanical vibrations). We will analyze its impact on both BPSK signals and the output results and evaluate phase stabilization methods to suppress it.