Theoretical analysis of the spectral gain and noise of single and double pass Er~(3+)-doped Ti:LiNbO_3 straight waveguide amplifiers

摘要

We report in this paper a theoretical analysis of some parameters which characterize the Er~(3+)-doped Ti:LiNbO_3 straight waveguide amplifiers. The derivation and the evaluation of the spectral optical gain, the spectral noise figure, the signal-to-noise ratio and the amplified spontaneous emission photon number are performed under the small gain approximation taking into account the overlap between the pump, signal and dopant distribution profiles. In our simulations the Er~(3+)-profile is considered erfc, Gaussian or constant in depth and Gaussian in width, with a surface concentration of about 7·10~(25)m~(-3) and a diffusion depth of 20 μm. The simulations show the evolution of these parameters under various pump regimes and waveguide lengths. The obtained results can be used for the design of complex rare earth doped integrated circuits.