Performance Enhancement of DWDM Systems Through Optical Delay-Assisted Optimization of Chirped Fiber Bragg Grating Apodization and Chirp Profiles

Chromatic dispersion (CD), together with polarization mode dispersion (PMD) and Kerr nonlinear effects, limits the performance of high-capacity DWDM optical communication systems. This study proposes an optical delay (OD)-assisted chirped fiber Bragg grating (CFBG) architecture in which a controlled temporal shift establishes favorable temporal alignment of the dispersed waveform before its wavelength-dependent group-delay compensation by the CFBG. An 8-channel DWDM system operating at 10 Gb/s per channel with 50 GHz channel spacing is investigated over transmission distances of 40–280 km, with CD, PMD, and Kerr nonlinear effects included in the transmission model. The proposed scheme is optimized using Gaussian, Tanh, and Uniform apodization functions with different chirp profiles and grating lengths. Simulation results show that the OD-assisted CFBG consistently outperforms the standalone CFBG configuration. The best performance is obtained with Gaussian apodization and linear chirp, for which the Q-factor increases from 35.61 to 51.46 over 100 km under optimized conditions. These results demonstrate that temporal pre-alignment provided by the OD enhances the effectiveness of CFBG-based dispersion compensation, thereby improving overall signal quality and transmission performance in DWDM systems.