Large‐Scale Monolithically‐Integrated High‐Speed Interconnect Chips via Direct Growth of InAs/GaAs Quantum Dot Lasers and Photodetectors on Si(001)

ABSTRACT Silicon photonic integrated circuits (PICs) have emerged as cutting‐edge platforms for optical communication, interconnection, photonic computing, and sensing, delivering exceptional data throughput and energy‐efficient operation. A holy grail is the realization of light sources and photonic components monolithically integrated on a single silicon wafer. However, such integration faces formidable challenges in material engineering and integration techniques, especially for on‐chip light sources. Here, we propose a strategy for developing large‐scale monolithically‐integrated high‐speed interconnect chips via direct epitaxy of quantum dot (QD) materials on CMOS‐compatible (001) silicon substrate. On the basis of an eight‐layer QD epitaxial structure, we simultaneously fabricate direct modulation lasers and waveguide photodetectors (PDs) for emission and reception. Bandwidth measurements for the single QD lasers and PDs reveal 3 dB bandwidths of 4.5 GHz and 2.02 GHz, respectively. Non‐return‐to‐zero (NRZ) signal measurements show that the laser can achieve a maximum direct modulation rate of 12.5 Gbit/s, whereas the PD has a data reception capability of 5 Gbit/s. Moreover, a state‐of‐the‐art link rate of 1.01 GHz for on‐chip optical interconnection between the integrated lasers and PDs is demonstrated through a free‐space optical coupling structure. This work demonstrates a novel method to realize large‐scale monolithically‐integrated chips, which enables future versatile applications.