Heterogeneous Photonic Integration by Direct Wafer Bonding

The silicon (Si) photonics platform has emerged as a promising integration platform for use in many applications, particularly datacenter communications, which is expected to produce demand for large numbers of low cost photonic integrated circuits (PICs). Sibased PICs are almost universally based on Si-on-insulator (SOI) wafers, which are enabled by wafer bonding technology. Si is useful as a waveguide material due to its high index contrast, low intrinsic absorption, and mature manufacturing technology. However, it does not strongly absorb or emit light in wavelength ranges of interest for data transmission. Heterogeneous integration of InP-based materials with Si using wafer bonding technology is able to overcome this limitation and has allowed the realization of a wide range of photonic devices on Si, including lasers, photodetectors, and modulators with high performance (1).