High power polarization-insensitive InGaAs-based Photomixer with extended metallic contact for THz communication systems

This work proposes and simulates a high-power polarization-insensitive InGaAs-based continuous-wave THz emitter. The mesh-like metallic contacts in the suggested structure significantly improve the transmission of the incident optical pump to the active region. The carefully designed metallic features substantially enhance the local bias field near contact edges where the majority of photoexcited carriers are formed. Furthermore, by the contribution of the extended metallic contacts, the photogenerated carriers effectively reach the contacts and lead to 10 times higher THz radiation compared to the structure without extended metallic contacts. The proposed structure generates identical THz photocurrent under different polarization of optical pump. This advantage makes it a great candidate for THz communication, which system’s robustness is crucial to environmental change. The simulation results indicate that under 240 mW unpolarized optical pump power, the optimized structure radiates 561 $\mu$W power at 500 GHz frequency.