Broadband 205-GHz vertical-illumination photodiode enabled by double field control layers

We demonstrate a high-speed, high-responsivity vertical-illumination InGaAs/InP photodiode (PD). Precise control of the internal electric-field profile using p- and n-type field-control layers reduces the electron transit time by using drift velocity overshoot, resulting in 3-dB bandwidth of 205 GHz. Furthermore, the device exhibited a high responsivity of 0.51 A/W while maintaining high 3-dB bandwidth by employing interference-based absorption enhancement technique. A low dark current of approximately 1 pA with excellent uniformity and high optical-power tolerance with a 1-dB compression current of 10 mA at 200 GHz are also demonstrated. Furthermore, eye patterns were obtained at data rates exceeding 180 Gbaud.