# Silicon nitride photonic chip: skyrmion topology of light survived the loss of photon entanglement

- Published: 2026-11-07 21:04 UTC
- Section: Digital & Computing › Quantum technology
- Tags: quantum skyrmion, quantum entanglement, silicon nitride photonic chip, topological protection, orbital angular momentum, light polarization, spontaneous four-wave mixing, microring resonators, quantum communication noise
- URL: https://realtech.media/news/rt-04ccf714f91c5bdd504b3d74_silicon_nitride_photonic/

**A US team built an integrated chip that encodes a quantum skyrmion in one photon of an entangled pair. Under added noise, entanglement vanished but the topological property largely held.**

![Silicon nitride photonic chip: skyrmion topology of light survived the loss of photon entanglement](https://realtech.media/media/2026/11/747709328f166c45.jpg)
*chip.pl*

A research team from the United States has built an integrated photonic chip made of silicon nitride. It generates entangled photons and imprints a quantum skyrmion pattern on one of them, according to a Nature Physics study covered by chip.pl. [1] In the experiment, the topological property of the pattern persisted after the entanglement between the photons had disappeared under added noise. [1]

## Quantum skyrmion and the chip

Entanglement is a correlation between particles in which the state of one is linked to the state of the other. It is very susceptible to disturbance: even relatively weak noise from the environment can destroy it and make information transfer harder. [1]

A quantum skyrmion is not a physical object but a specific arrangement of light properties, related to polarization and orbital angular momentum. Polarization describes the direction of oscillation of the light wave, while orbital angular momentum describes how its wavefront is twisted. Combining these parameters produces a pattern whose mathematical properties are described by topology, and its key feature is resistance to local perturbations. [1]

The chip combines several functions: it generates entangled photons, routes them along the required paths and imprints the skyrmion pattern on one of them. Photon pairs were produced with femtosecond laser pulses and a process called spontaneous four-wave mixing. Microring resonators then combined the light properties and encoded the structure. [1]

## Measurements and noise tests

The researchers also ran measurements that allowed them to reconstruct the quantum state of the system. The topological number of the primary skyrmion came out at 1.981, close to the expected value of 2. For the transferred two-photon states, the average quantum state fidelity reached 89 percent. [1]

In the next stage the team deliberately introduced disturbances, raising the noise level, among other ways by adding unwanted background light. As the noise grew, the quantum state gradually degraded and the entanglement between the photons eventually vanished. The topological property of the skyrmion, however, remained largely unchanged. Only considerably stronger disturbances destroyed the whole pattern. [1]

This supports the assumption that the topological properties of light are more resistant to noise than previously thought. [1]

## Sources

1. [chip.pl](https://www.chip.pl/2026/11/wzor-w-swietle-przetrwal-zerwanie-kwantowe)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-04ccf714f91c5bdd504b3d74_silicon_nitride_photonic/