Ultracompact autocorrelator with pulse-width-range switch function integrated on a silicon photonic chip

Abstract

Abstract We demonstrated a fully integrated autocorrelator that can switch the measurable range of the pulse width. The autocorrelator was fabricated on a chip using a silicon photonics process. Autocorrelation was achieved using a two-photon absorption photodiode (TPA-PD) array embedded on a Si waveguide. We integrated multiple TPA-PD array waveguides on a chip to provide multiple pulse width ranges for the extension of the range. The switching of the waveguides was carried out using an integrated optical path switch. We fabricated two parallel waveguides with lengths of 110 and 330 μm, and a path switch consisting of a thermally controlled Mach–Zehnder interferometer. Correlation waveforms of picosecond pulses were appropriately obtained, and range switching was successfully performed. We show that the proposed device is scalable for the increase in the number of autocorrelators and the number of pulse-width ranges.