High-resolution measurement of energy correlations of photon pairs generated in silicon ring resonators

Integrated structures, such as micro-ring resonators, have been shown to have potential as “on- chip” sources of time-energy entangled photons. In these devices, photon pairs are generated by spontaneous four-wave-mixing (SFWM), an elastic scattering event involving two pump photons that results in the generation of an idler and signal photon. The mass production of integrated devices requires the implementation of fast and reliable techniques to monitor the fabrication process and the device performances. In this work we show that the joint spectral density of photon pairs that would be generated by SFWM in a silicon ring resonator can be measured with unprecedented resolution and speed, improving of several orders of magnitudes the results of traditional approaches based on coincidence measurements.