This document discusses inter-DCI and co-packaged optics. It provides an overview of data center architecture and challenges in data centers including high-speed interfaces between silicon and optics. The document then discusses integrated coherent transmit-receive optical sub-assemblies and co-packaged optics as potential solutions. Co-packaged optics could provide a compact form factor with many modules close to switch ASICs and include electronics, modulators, receivers and lasers to allow for high data rates and simplified assembly at a lower cost. External and integrated laser integration approaches are also briefly outlined.