  We describe the design of a temporal imaging system that simultaneously
reshapes the temporal profile and converts the frequency of a photonic
wavepacket, 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 wavepackets 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 (GDD) $D$ is constrained
by the available bandwidth $\Delta\nu$ by $D>t/\Delta\nu$, where $t$ is the
temporal width of the waveform 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.
