  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.
