  The ability to manipulate single photons is of critical importance for
fundamental quantum optics studies and practical implementations of quantum
communications. While extraordinary progresses have been made in controlling
spatial, temporal, spin and orbit angular momentum degrees of freedom,
frequency-domain control of single photons so far relies on nonlinear optical
effects, which have faced obstacles such as noise photons, narrow bandwidth and
demanding optical filtering. Here we demonstrate the first integrated
near-unity efficiency frequency manipulation of single photons, by stretching
and compressing a waveguide at 8.3 billion cycles per second. Frequency shift
up to 150 GHz at telecom wavelength is realized without measurable added noise
and the preservation of quantum coherence is verified through quantum
interference between twin photons of different colors. This single photon
frequency control approach will be invaluable for increasing the channel
capacity of quantum communications and compensating frequency mismatch between
quantum systems, paving the road toward hybrid quantum network.
