Dynamic control of photon lifetime for quantum random number generation

In a passive cavity geometry, there exists a trade-off between resonant enhancement and response time, which is inherently limited by the cavity photon lifetime. We demonstrate frequency-selective, dynamic control of the photon lifetime using a silicon-nitride coupled-ring resonator. The photon lifetime is tuned by controlling an avoided mode crossing using thermo-optic tuning of the cavity resonance with integrated heaters. Using this effect, we achieve fast turn-on/off of a chi((3)) degenerate optical parametric oscillator (DOPO) and on-chip true random number generation. Our approach allows us to overcome the Q-limited generation rate of a single-ring-based DOPO and offers a path toward the development of a scalable integrated high-quality entropy source for modern cryptographic systems. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.

Automated summary

This study demonstrates dynamic control of photon lifetime using a silicon-nitride coupled-ring resonator, allowing for fast switch operations and on-chip true random number generation. It overcomes the Q-limited generation rate of DOPO and offers a new path for developing high-quality entropy sources.