Quantum Photonic Chip

Quantum technology based on light (photons) is called quantum photonics, while electronics is based on electrons. Photons (light particles) and electrons behave differently at the quantum level. A quantum entity is the smallest unit in the microscopic world. For example, photons are the fundamental constituent of light and electrons of electric current. Electrons are so-called fermions and can easily be isolated to conduct current one electron at a time. In contrast, photons are bosons, which prefer to bunch together. But since information for quantum communication based on photonics is encoded in a single photon, it is necessary to emit and send them one at a time.

Increased Information Capacity

Information based on photons has great advantages; photons interact only very weakly with the environment -- unlike electrons, so photons do not lose much energy along the way. Photons are therefore very well suited for carrying and distributing information and will be able to encode much more information than is possible with current computer technology.

Control of the Photons

A prerequisite for Photonic Chip is the ability to create a stream of single photons on demand. The photonic chip consists of an extremely small crystal that is 10 microns wide (one micron is a thousandth of a millimeter) and is 160 nanometers thick (1 nanometer is a thousandth of a micron). Embedded in the middle of the chip is a light source, which is a so-called quantum dot.

Illuminating the quantum dot with laser light excites an electron, which can then jump from one orbit to another and thereby emit a single photon at a time. Photons are usually emitted in all directions, but the photonic chip is designed so that all the photons are sent out through a photonic waveguide.

Normally, the photons are transmitted in both directions in the photonic waveguide, but in their custom-made photonic chip they could break this symmetry and get the quantum dot to differentiate between emitting a photon right or left, that means emit directional photons. This means full control over the photons.