Picosecond laser pulses for quantum dot–microcavity-based single-photon generation by cascaded electro-optic modulation of a narrow-linewidth laser

Recent progress has made high-bandwidth electro-optic modulators (EOMs) available. Here we show the cascaded operation of two such modulators driven by custom-built electronics delivering on-demand picosecond pulses and application to a quantum dot–cavity-QED single-photon source. We implement an EOM-based correlation technique and demonstrate light pulses as short as 24±2 ps with a single EOM. The EOMs can be synchronized and operated in series, and we then produce optical pulses down to 17 ps. To optimize the pulse contrast, for two different EOM devices, we analyze the transmission as a function of EOM bias, wavelength, and temperature, and we show that, by temperature tuning and stabilization, a pulse contrast above 25 dB can be obtained at the targeted wavelength. With this high contrast, we demonstrate resonant excitation of an InGaAs quantum dot–microcavity-based single-photon source, demonstrating a crucial technology for scalability and synchronization of large-scale photonic quantum applications.