High contrast asymmetric Fabry–Perot electro-absorption modulator with zero phase change

By analyzing the exciton line shapes of quantum wells, we can determine the wavelengths and biases at which they exhibit large absorption changes and zero refractive index changes relative to zero bias. To use this effect, we placed GaAs/AlGaAs quantum wells in the intrinsic region of a reverse-biased p-i-n diode asymmetric Fabry–Perot modulator. We then developed a sample that could be post-growth processed to optimize all relevant parameters. We used computer simulation to determine the exact post-growth correction required and produced reflection modulators with 90% reflection change and zero relative phase change.