Cavity integrated quantum key distribution

We present a scalable Quantum Key Distribution (QKD) transmitter based on an integrated ring cavity that directly enables high-rate quantum communications that take advantage of parallelism enabled by wavelength-division multiplexing. The ring cavity modulates single photons using the plasma dispersion effect when current is injected into the p-i-n junction surrounding the cavity. To demonstrate the system’s feasibility, we generated secret keys using the coherent-one-way protocol at a rate higher than 236 kbps in a field test between two different laboratories at MIT.