Dispersion-induced pulse broadening and compression method in underwater wireless optical communication

Abstract This paper proposes an underwater pulse transmission model and an optimization model for pulse compression to mitigate the problem of pulse broadening in underwater transmission, which reduces the data rate of underwater wireless optical communication (UWOC). Deriving from the Lorentz–Lorenz equation and the Schrödinger equation, the underwater pulse propagation model is established, from which we can obtain the temporal evolution of the pulse over time and propagation distance in water. To address the pulse broadening, a nonlinear optimization model is then developed to determine the optimal dispersion compensation parameters. The results demonstrate that this approach can effectively handle ultrafast laser pulses with an initial width of 50 fs, which undergo a 6.2-fold broadening as they propagate through water. The nonlinear optimization model provides targeted dispersion compensation for the broadened pulse, restoring its original width. The method presented in this paper offers substantial theoretical value and practical potential for high-speed UWOC applications.