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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 mu m. 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.