  In the circuit quantum electrodynamics architectures, to realize a long-range
quantum network mediated by flying photon, it is necessary to shape the
temporal profile of emitted photons to achieve high transfer efficiency between
two quantum nodes. In this work, we demonstrate a new single-rail and dual-rail
time-bin shaped photon generator without additional flux-tunable elements,
which can act as a quantum interface of a point-to-point quantum network. In
our approach, we adopt a qubit-resonator-transmission line configuration, and
the effective coupling strength between the qubit and the resonator can be
varied by parametrically modulating the qubit frequency. In this way, the
coupling is directly proportional to the parametric modulation amplitude and
covers a broad tunable range beyond 20 MHz for the sample we used.
Additionally, when emitting shaped photons, we find that the spurious frequency
shift (-0.4 MHz) due to parametric modulation is small and can be readily
calibrated through chirping. We develop an efficient photon field measurement
setup based on the data stream processing of GPU. Utilizing this system, we
perform photon temporal profile measurement, quantum state tomography of photon
field, and quantum process tomography of single-rail quantum state transfer
based on a heterodyne measurement scheme. The single-rail encoding state
transfer fidelity of shaped photon emission is 90.32%, and that for unshaped
photon is 97.20%, respectively. We believe that the fidelity of shaped photon
emission is mainly limited by the qubit coherence time. The results demonstrate
that our method is hardware efficient, simple to implement, and scalable. It
could become a viable tool in a high-quality quantum network utilizing both
single-rail and dual-rail time-bin encoding.
