# On-chip generation of photon-triplet states

## TL;DR

This paper reports on an integrated chip that efficiently generates photon triplet states at telecom wavelengths, advancing scalable quantum technologies with high stability and low noise.

## Contribution

The authors demonstrate a monolithically integrated source of photon triplets with high efficiency, stability, and low noise, suitable for scalable quantum applications.

## Key findings

- Successful generation of photon triplets at telecom wavelengths.
- High stability and low interface losses of the integrated source.
- Potential for scalability and integration into quantum networks.

## Abstract

Efficient sources of many-partite non-classical states are key for the advancement of quantum technologies and for the fundamental testing of quantum mechanics. We demonstrate the generation of time-correlated photon triplets at telecom wavelengths via pulsed cascaded parametric down-conversion in a monolithically integrated source. By detecting the generated states with success probabilities of $(6.25\pm1.09)\times10^{-11}$ per pump pulse at injected powers as low as $10\;\mu\mathrm{W}$, we benchmark the efficiency of the complete system and deduce its high potential for scalability. Our source is unprecedentedly long-term stable, it overcomes interface losses intrinsically due to its monolithic architecture, and the photon-triplet states dominate uncorrelated noise significantly. These results mark crucial progress towards the proliferation of robust, scalable, synchronized and miniaturized quantum technology.