Tradeoff between phase- and intensity modulation in GaAs/AlGaAs double heterostructure and multiple quantum well phase-modulator waveguides

The wavelength dependence of phase sensitivity ( degrees /mm V) and intensity modulation of a double-heterostructure (DH) device and a multiquantum-well (MQW) device in the GaAs/AlGaAs material system is studied. The results show the tradeoff between phase modulation and intensity modulation and also show that, for the same intensity modulation, the MQW device produces twice as much phase modulation as the DH device. For example, at an intensity modulation of -1 dB the MQW device has a phase sensitivity of 120 degrees /mm V while the DH device gives a value of approximately=60 degrees /mm V.>