MATLAB Code for Erbium Doped Fiber Amplifier (EDFA) Modeling

The Erbium Doped Fiber Amplifier (EDFA) is an optical amplification device that utilizes a specially prepared fiber of length L, where the core is uniformly doped with Erbium ions. From a quantum mechanical perspective, these ions function as two-level systems, meaning they exist in either their fundamental ground state or an excited energy state. To stimulate these ions, a high-power pump laser operating at typical wavelengths of 980 nm or 1480 nm is injected into the fiber core. In MATLAB implementations, this pump propagation can be modeled using coupled differential equations that track power evolution along the fiber length. The pump photons are absorbed by Erbium ions, elevating them from the ground state to the excited state through optical pumping mechanisms. When ions reside in the excited state, they can undergo stimulated emission, releasing photons and returning to the ground state. The MATLAB simulation typically employs rate equations to model population inversion dynamics, where photon interactions within the fiber stimulate additional Erbium ions to emit coherent photons. This cascade effect results in significant amplification of the input optical signal traveling through the fiber. In computational modeling, key functions include solving coupled power propagation equations for both signal and pump wavelengths, implementing energy level transition probabilities, and calculating gain coefficients based on population inversion. The complete EDFA model effectively demonstrates how optical signals are amplified through strategic doping and pump laser excitation in fiber optic systems.