  Operator spreading, often characterized by out-of-time-order correlators
(OTOCs), is one of the central concepts in quantum many-body physics. However,
measuring OTOCs is experimentally challenging due to the requirement of
reversing the time evolution of systems. Here we apply Floquet engineering to
investigate operator spreading in a superconducting 10-qubit chain. Floquet
engineering provides an effective way to tune the coupling strength between
nearby qubits, which is used to demonstrate quantum walks with tunable
couplings, reversed time evolution, and the measurement of OTOCs. A clear
light-cone-like operator propagation is observed in the system with multiple
excitations, and has a nearly equal velocity as the single-particle quantum
walk. For the butterfly operator that is nonlocal (local) under the
Jordan-Wigner transformation, the OTOCs show distinct behaviors with (without)
a signature of information scrambling in the near integrable system.
