Intracavity piezoelectric InGaAs/GaAs laser modulator

Integration of a laser and modulator is shown to be possible in the InGaAs/AlGaAs material system by growing on a B GaAs substrate and utilizing the piezoelectric effect. The absorption characteristics of the modulator section are initially red shifted due to the built-in piezoelectric field and can be easily blue shifted with applied reverse bias. Since even under lasing conditions there is found to be a significant residual piezoelectric field in the quantum well, the modulator can be biased to a shorter wavelength than the lasing emission. Utilizing these effects a simple two-section laser-modulator device in which the absorber section lies within the laser cavity has been fabricated. The result show that the threshold current of the laser- modulator structure is controlled by the reverse bias voltage and hence absorption in the modulator section.