Isotropic Material Gallium Arsenide Based Electro-Optic Phase Modulator

Gallium Arsenide (GaAs) is a III-V semiconductor which offers a prospective attribute in the designing of an Electro-Optic Phase modulator. When an external electric field is applied, the refractive index of Gallium Arsenide varies linearly due to the Pockels effect. This change in refractive index gives the phase modulation of the input signal. This paper demonstrates external phase modulators based on Gallium Arsenide material due to Pockels effect which is modelled using MATLAB tool. A Critical Parameter in this work is the half-wave voltage (Vπ), voltage required to induce a phase shift(π) in the transmitted light. This voltage is inversely proportional to the electro-optic coefficient of the GaAs material. Electro-Optic Coefficient determines the level of refractive index change in a material when an Electric Field is applied. For Gallium Arsenide material, with an electro-optic coefficient γ41, the half-wave voltage is calculated. When Half Wave voltage is induced across the Gallium Arsenide material, a phase shift is achieved and makes the Gallium Arsenide work as a Phase modulator. Lower the half-wave voltage, faster and efficient is the modulation, which is crucial for the high-speed communication systems. This can be achieved by optimizing device geometry, leading to more compact, power-efficient, and high-performance modulators.