Collaborative Project “HiPEQ”

The collaborative project "Highly Integrated PIC-based ECDLs for Quantum Technology" (HiPEQ) focuses on the development of an innovative platform for miniaturized single-mode and narrow-band diode lasers ("External Cavity Diode Laser", ECDL) based on photonic-integrated circuits (PIC) in the visible spectral range. Narrowband fully integrated lasers are needed in various quantum technology applications such as the realization of ion-based quantum computers, quantum communication as well as quantum sensing.

On the one hand, Fraunhofer ILT is working on the realization of laser-manufactured 3D precision components for the interface and connection components between the PIC and the fiber. The so-called selective laser-induced etching (SLE) process and laser polishing are used for this purpose. The SLE process offers a high spatial precision of about 1 µm as well as an almost complete freedom of geometry for the design of the components. As a result, a monolithic component can be produced and the adjustment effort for the components can be significantly reduced. In addition, it is also possible to manufacture a hermetically sealed system.

On the other hand, a monocrystalline optical isolator with a comparatively large Verdet constant is required for the realization of a miniaturized ECDL. Due to the high melting point of more than 2000°C, the crucible-free laser floating zone process is used for growing these insulator crystals, in which the nutrient rod and seed crystal are remelted in a locally confined area using multi-kW laser radiation. For this purpose, an optical system for beam shaping and guiding is being developed at Fraunhofer ILT in a second work package, which will be used together with a high-power diode laser to grow novel insulator crystals with large Verdet constants.

Duration of the project 

1.11.2021 - 31.07.2025