About Photonic Integrated Circuits

Integrated Photonics

Integrated Photonics is a technology quite similar to the much more known Integrated Electronics. Electronic Integrated Circuits (IC’s) have formed the basis of the ICT revolution since the 1960’s. In IC’s initially several, but currently upto billions of microelectronic components are packed onto a small piece of semiconductor material, mostly silicon. By switching electrons all around the circuit, advanced electronic devices like microprocessors, memory, radio transmitters and receivers and many more can be made. Your computer, smartphone, tv, car and whatever are actually packed with IC’s.

Photonic Integrated Circuits (PIC’s) actually do the same as Electronic Integrated Circuits, but instead of electrons, photons are manipulated in many ways by the circuits. Since photons are in fact small packets of energy (unlike electrons which are particles having a mass) photons can simply disappear by absorption by the material in which they propagate. Therefore, PIC-technology is far more demanding than microelectronics. PIC’s are made of semiconducting materials which can contain light sources (lasers) e.g. Indium-Phosphide (InP) or Gallium-Arsenide (GaAs), semiconducting materials which cannot contain light sources (e.g. silicon) or dielectric materials like silicon oxide or silicon nitride (actually: various types of glass).

Initially, semiconductor based photonic devices were used in telecom applications; the renowned glass fiber communication technology. However, it was discovered that photons can be captured and manipulated in very small waveguides integrated on semiconductor or dielectric substrates as well. This opened the way to more complex photonic devices, the photonic chips. Photonic chips, although harder to make, have been demonstrated to surpass the properties of electronic chips or are used for very different applications benefitting from the properties of light and waveguides (see the applications page).