The field of quantum optics offers new ways to compute, communicate, and measure with quantum states. Recent advances in materials, quantum control, and nanofabrication now open the prospect for scalable quantum technologies based on solid-state quantum systems. In particular, photonic integrated circuits (PICs) now allow routing photons with high precision and low loss, and atom-like systems in semiconductors enable spin-based quantum memories that can be coupled to these optical circuits. The first part of this talk will review our recent progress in adapting one of the leading PIC architectures—silicon photonics—for various quantum secure communications protocols. The second part of the talk will consider how PIC technology, integrated with quantum memories, can extend the reach of quantum communications and form the basis of modular quantum computers.