High‐Bandwidth InGaAs Photodetectors Heterogeneously Integrated on Silicon Waveguides Using Optofluidic Assembly

Abstract Light‐induced manipulation techniques have been utilized to transport, trap, or levitate microscopic objects for a wide range of applications in biology, electronics, and photonics. Without making direct physical contact, they can provide simple yet powerful means for high‐precision assembly of microscale functional blocks and components within the integrated circuit platforms, thereby offering a viable alternative to the conventional heterogeneous integration techniques, such as wafer/die bonding and transfer printing. Using a microbubble‐based optofluidic pick‐and‐place assembly process, heterogeneous integration of compact III‐V semiconductor photodetectors on a silicon‐based photonic integrated circuit chip, enabling direct high‐speed vertical electrical contacts for significantly improved photogenerated carrier transit distance/time, is experimentally demonstrated. The microdisk‐shaped InGaAs p‐i‐n photodetector integrated on the silicon waveguide has a 3 dB bandwidth exceeding 50 GHz under the applied bias voltage of −1 V for near‐infrared wavelengths around 1.55 µm. The light‐induced optofluidic assembly will provide a promising route for seamless heterogeneous integration of various optoelectronic components with high‐speed and low‐noise electrical interconnection on the fully processed silicon photonic/electronic integrated circuit platforms.