In this thesis work, is made an evaluation of modulators of amplitude based in the electrum-absorption effect.The structures used for the devices were multiple quantum wells of InAlAs/InGaAs and AlGaAs/GaAs.The structures of InAlAs/InGaAs are used to work in the commercial band of the telecommunications (1,55 µm).This is the reason it is important to optimize the parameters of performance of the device, such as the Stark shift, chirp, contrast reason, insertion loss, etc.Previously, a systematic study of these structures was made by [Pires, 1998], the gallium concentration was varied to produce a strain in the structure and to modify the optic properties of the material.In the study of [Pires, 1998] considered the Gallium concentration was varied between 46% and 52% in which range the best condition to operate the device can be found.This is part of the work here presented.In this thesis this range of values was studied in more detail.For the structures of AlGaAs/GaAs, a theoretical proposal of [Batty et al, 1993] was experimentally investigated.It was suggested a nipi structure to use a fine delta doped (δ) in the GaAs wells, this delta doped will improve in 87% the Stark shift for a field of 40 KV/cm.The device was simulated and manufactured, obtaining a value of 78 % for the same field applied, this is a excellent result, because this confirm the theoretical prediction.