Frequency-bin entanglement from domain-engineered down-conversion

Frequency encoding is quickly becoming an attractive prospect for quantum information protocols owing to larger Hilbert spaces and increased resilience to noise compared to other photonic degrees of freedom. To fully make use of frequency encoding as a practical paradigm for QIP, an efficient and simple source of frequency entanglement is required. Here we present a single-pass source of discrete frequency-bin entanglement which does not use filtering or a resonant cavity. We use a domain-engineered nonlinear crystal to generate an eight-mode frequency-bin entangled source at telecommunication wavelengths. Our approach leverages the high heralding efficient and simplicity associated with bulk crystal sources.