  Top-performance sources of photonic entanglement are an indispensable
resource for many applications in quantum communication, most notably quantum
key distribution. However, up to now, no source has been shown to
simultaneously exhibit the high pair-creation rate, broad bandwidth, excellent
state fidelity, and low intrinsic loss necessary for gigabit secure key rates.
In this work, we present for the first time a source of polarization-entangled
photon pairs at telecommunication wavelengths that covers all these needs of
real-world quantum-cryptographic applications, thus enabling unprecedented
quantum-secure key rates of more than 1 Gbit/s. Our source is designed to
optimally exploit state-of-the-art telecommunication equipment and detection
systems. Any technological improvement of the latter would result in an even
higher rate without modification of the source. We discuss the used
wavelength-multiplexing approach, including its potential for multi-user
quantum networks and its fundamental limitations. Our source paves the way for
high-speed quantum encryption approaching present-day internet bandwidth.
