Monolithic bistable e´talons with a GaAs/Al0.3Ga0.7As multiple quantum well active layer and AlAs/Al0.1Ga0.9As Bragg reflectors have been fabricated by metalorganic vapor phase epitaxy. They exhibit a very good memory effect. Experiments with an additional external beam at the same and at a different wavelength have been performed. They demonstrated thresholding, pulse shaping, amplification, and wavelength conversion. Moreover, the use of a diode laser external beam showed the possibility of controlling an intense beam with a weaker beam. We describe an experimental configuration in the reflection mode and at normal incidence, which allows mixing the two input beams and extracting the output beam with an ideal 100% efficiency.