Performance Evaluation of the Encrypted Image Transmission System Over Optical Fiber Using OptiSystem Under Varying Channel Conditions

Abstract

This paper presents the design, simulation, and performance analysis of an end-to-end optical communication link for encrypted grayscale-image transmission. Advanced Encryption Standard (AES) is applied to encrypt the image in MATLAB and then convert a 256 × 256 image into a binary sequence, which is then injected into OptiSystem. for optical modulation and fiber-optic  transmission. Three operating wavelengths) 810 nm, 1550 nm, and 1625 nm( are investigated over distances of 50 km, 80 km, 100 km, and 150 km under different dispersion and attenuation conditions. Both a conventional Optical Amplifier (OA) and an Erbium-Doped Fiber Amplifier (EDFA) are considered. The performance of the system is assessed through various metrics in the electrical domain, such as the Q-Factor and Bit Error Rate (BER), alongside image quality indicators like Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Index (SSIM), and Mean Squared Error (MSE). The results prove that the 1550 nm band yields error-free recovery (BER ≈ 10⁻¹⁷⁶, PSNR = 54 dB, SSIM = 1.0) under realistic single-mode-fiber parameters (α = 0.2 dB/km, D = 16 ps/nm/km). Conversely, heavy attenuation (α = 2.5 dB/km) and dispersion (D = 10 ps/nm/km) degrade performance severely, especially at 810 nm. The study highlights the importance of wavelength selection and dispersion management for secure image delivery and provides a reproducible methodology combining MATLAB and OptiSystem. Future research can extend this work by exploring adaptive dispersion compensation, forward error correction, and advanced modulation schemes