Correcting coupler pulse distortions in superconducting qubits

High-fidelity CZ gates in superconducting qubits with flux-tunable couplers critically depend on the precise control of coupler pulses, whose performance is often degraded by distortions. We present a novel model-free approach to overcoming this coupler pulse distortion problem through precise measurements and pre-distortion. Our technique measures the coupler flux-pulse transfer function in the frequency domain. Experimental validation confirms that pre-distorted pulses based on the measured transfer function improve the CZ gate performance by over 20% by reducing leakage out of the computational subspace.