Simultaneous Frequency Conversion and Spectral-Temporal Shaping of Single-Photon Pulses

We demonstrate a quantum interface that simultaneously converts the wavelength, bandwidth, and duration of single-photon-level pulses, enabling compatibility between disparate quantum systems. Using difference frequency generation in a lithium niobate waveguide driven by a highly chirped pump, we transform pulses from 798 nm, 5 GHz, 150 ps (quantum dot-like) to 1300 nm, 35 GHz, < 25 ps (telecom standard). This nonlinear optical time lens achieves over 80% internal conversion efficiency and compresses output pulses below detector resolution. The device offers a compact solution for integrating quantum emitters, memories, and telecom networks, with potential for further pulse shape control.