Ultra-broadband UTC-PD beyond 110 GHz at 0 V for future photonic integration

We have successfully realized the non-bias operation of an ultra-wide bandwidth uni-traveling-carrier photodetector (UTC-PD) using a low carrier concentration of 3 × 10¹⁴ cm⁻³ in the carrier collection layer for future high-density photonic integration. A 3-dB bandwidth above 110 GHz was confirmed without a bias circuit. In this paper, we discuss the proposed design and the experimental results obtained for the frequency response and maximum RF output power.