We describe the design of a temporal imaging system that simultaneously reshapes the temporal profile and converts the frequency of a photonic wave packet, while preserving its quantum state. A field lens, which imparts a temporal quadratic phase modulation, is used to correct for the residual phase caused by field curvature in the image, thus enabling temporal imaging for phase-sensitive quantum applications. We show how this system can be used for temporal imaging of time-bin entangled photonic wave packets and compare the field lens correction technique to systems based on a temporal telescope and far-field imaging. The field-lens approach removes the residual phase using four dispersive elements. The group delay dispersion $D$ is constrained by the available bandwidth $\Delta \nu$ by $D>t/\Delta \nu$, where $t$ is the temporal width of the wave form associated with the dispersion $D$. This is compared to the much larger dispersion $D\gg \pi t^2/8$ required to satisfy the Fraunhofer condition in the far-field approach.

• Received 7 March 2013

DOI:https://doi.org/10.1103/PhysRevA.87.043808