Silicon-Photonics-Embedded Interposers as Co-Packaged Optics Platform

We propose silicon (Si)-photonics-embedded interposers as a novel packaging platform to achieve co-packaged optics. An interposer is an organic substrate that has Si-photonics transceiver dies buried in it and polymer optical waveguides connecting the embedded Si chips and optical connectors. We also developed a Si-photonics-device-embedding process and investigated the properties and operations of embedded Si-photonics devices as a feasibility study. The embedded arrayed waveguide grating and reflective optical filter showed a wavelength shift on the order of 0.1 nm with our embedding process. The shifts seem to be due to the difference in ambient temperature during the measurements and induced strain. Though this embedding process is presumed to affect the spectrum for Si-photonics devices, the difference is small enough to be controlled. Embedded Si-photonics transmitter- and receiver-integrated circuits successfully demonstrated 25-Gb/s operations. The proposed Si-photonics-embedded interposer is a promising candidate for a co-packaged optics platform to eliminate the interconnect bandwidth bottleneck for high-performance computing systems.