Cisco quantum switch chip prototype.
Cisco
Scale up or scale out? This question is currently being hotly debated in the quantum scene. Essentially, it’s about considering what makes more economic sense and can be realized technologically faster: building huge quantum computers with QPUs with several thousand qubits, or networking smaller quantum computers in a network in order to scale their computing power?
Both approaches have their hooks and eyes. In January, for example, the Nobel Prize winner for Physics 2025, John Martinis, criticized that “we are currently still building qubits in an almost hand-crafted way”. But there are still many question marks on the other side, when it comes to networking. In a recent CW interview, Ramana Kompella, Head of Cisco Research, was conspicuously reluctant to give a specific date as to when a breakthrough in quantum networking can be expected.
The switch as a quantum interpreter
Cisco now seems to have achieved such a breakthrough with the prototype of a Universal Quantum Switch. One challenge in networking was that the information in the quantum systems is encoded in a variety of ways – for example via the polarization of light or the frequency. So far, an exchange has hardly been possible without destroying the highly sensitive quantum information.
