Waveguide coupled III-V photodiodes monolithically integrated on Si

TL;DR

This paper demonstrates monolithically integrated III-V photodiodes on silicon with high-speed performance, low dark current, and dual functionality as emitters, advancing integrated photonics technology.

Contribution

It presents the first scaled, waveguide-coupled III-V photodiodes monolithically integrated on silicon with high-speed operation and dual functionality as emitters.

Findings

Dark current as low as 0.048 A/cm2 at -1 V

Responsivity up to 0.2 A/W at -2 V

Cutoff frequency exceeding 70 GHz and 50 GBd data reception

Abstract

The seamless integration of III-V nanostructures on silicon is a long-standing goal and an important step towards integrated optical links. In the present work, we demonstrate scaled and waveguide coupled III-V photodiodes monolithically integrated on Si, implemented as InP/In0.5Ga0.5As/InP p-i-n structure. The waveguide coupled devices show a dark current down to 0.048 A/cm2 at -1 V and a responsivity up to 0.2 A/W at -2 V. Using grating couplers centered around 1320 nm, we observed a cutoff frequency f3dB exceeding 70 GHz and data reception at 50 GBd with OOK and 4PAM. When operated in forward bias as light emitting diode, the devices emit light centered at 1550 nm. Furthermore, we also investigate the self-heating of the devices using scanning thermal microscopy and find a temperature increase of only ~15 K during the device operation as emitter, in accordance with thermal simulation results.