InAs/InP Quantum Dash Based Electro Optic Modulator with Over 70 NM Bandwidth at 1.55 μM

We demonstrate the potential of InAs/InP quantum dash-based phase modulator for broadband (≫70 nm) applications at 1.55 μm. In recent years, there have been great efforts in the development of self assembled quantum dot nanostructures. This material system is expected to offer unique optoelectronic properties owing to the carrier confinement in the three space dimensions. Much works have been devoted so far to the realization of QD based lasers with the demonstration of superior performances compared to those of quantum well based lasers. Indeed, very low threshold current densities, temperature insensitivity, sub-picosecond pulse generation in mode locked lasers have readily been demonstrated. All-optical signal processing has also been investigated using semiconductor optical amplifiers. However, less research has been made in the field of light modulation using QD-based devices. In this paper, we report for the first time a systematic investigation of the electro-optic effect using an waveguide structures including 6-and 10-InAs/InP QDash layers of bandgap at 1.44 μm. Modulation efficiencies based on Pockels effect are found equal to /sp tilde/ 10.5 7 °/ V.mm and stays constant over a bandwidth of ˜70 nm covering the 1530-1600 nm window.