Research on InGaAsP/InGaAs High-Performance MUTC Photodiodes with Monolithic Integrated Microlens

In this paper, a modified uni-traveling-carrier photodiode (MUTC-PD) of InGaAsP/lnGaAs material with a transition layer is proposed to have high-bandwidth and high RF output power performance under high-power operating conditions. Considering the incident light problem of a small mesa diameter size photodiode (PD), an InP microlens is monolithically integrated on the backside of the device. The MUTC-PDs with mesa diameters of 6 $\mu\mathrm{m}, 3 \mu\mathrm{m}$, and 1.5 $\mu\mathrm{m}$ have transport bandwidths of 325 GHz, 335 GHz, and 365 GHz. 3-dB bandwidths of 137 GHz, 203 GHz, and 255 GHz are obtained. The peak output powers at 100 GHz, 150 GHz, and 200 GHz are 19.9 dBm, 19.4 dBm, and 14.7 dBm, and the corresponding photo currents at the peak output powers are 62.6 mA, 59.9 mA, and 58.1 mA.