  Neutral atom platform has become an attractive choice to study the science of
quantum information and quantum simulation, where intense efforts have been
devoted to the entangling processes between individual atoms. For the
development of this area, two-qubit controlled-PHASE gate via Rydberg blockade
is one of the most essential elements. Recent theoretical studies have
suggested the advantages of introducing non-trivial waveform modulation into
the gate protocol, which is anticipated to improve its performance towards the
next stage. We report our recent experimental results in realizing a two-qubit
controlled-PHASE($C_Z$) gate via off-resonant modulated driving(ORMD) embedded
in two-photon transition for Rb atoms. It relies upon a single modulated
driving pulse with a carefully calculated smooth waveform to gain the
appropriate phase accumulations required by the two-qubit gate. Combining this
$C_Z$ gate with global microwave pulses, two-atom entanglement is generated
with the raw fidelity of 0.945(6). Accounting for state preparation and
measurement (SPAM) errors, we extract the entanglement operation fidelity to be
0.980(7). Our work features completing the $C_Z$ gate operation within a single
pulse to avoid shelved Rydberg population, thus demonstrate another promising
route for realizing high-fidelity two-qubit gate for neutral atom platform.
