Nanophotonics: Fiber-Chip-Coupling

AMO GmbH is project partner within a new joint ZIM project named `Fiber-Chip-Coupling´. Project partners besides AMO are LightFab GmbH also located in Aachen as well as Aifotec AG from Meiningen.

The goal of the project is to demonstrate a possible solution for a vital problem of integrated silicon photonics. Integrated photonics is well on the way to trigger a revolution within the field of optical components similar to electrical components after the invention of the microprocessor in the seventies. The key to success was the integration of discrete devices like diodes and transistors onto microchips the size of cent coins. Besides massive advantages in dimensions and cost, the new solutions for integrated photonics are promising significantly enhanced stability and device reliability, as the individual components do not have to be aligned to each other anymore. Thus, the integration of more components becomes feasible, enabling the realization of more complex functionality.

The extremely small dimensions of silicon photonic devices, however, turn into a disadvantage as soon as the chips are to be coupled to the outside world with fibers. This optical connection is created by grating couplers which diffract the light via interference at nanometer scaled subwavelength structures almost perpendicularly to the plane of the chips. For efficient coupling, fibers have to be aligned and mounted accurately along six axes. Even with several fibers combined within a pre-assembled array, 80% of the overall cost is for the packaging of the chips.

The joint project started in March 2017 and aims to solve this problem with a new approach. The core of the idea is an assembling aid in form of a highly precise monolithic glass block with passive optics, fabricated by LightFab and improved by AMO. This shall make it possible for the first time to mount the fibers temperature-stable in the plane of the chips at the end of the packaging process. Thus, significantly cheaper automatic handling of the devices will be possible.

The joint project ‘Fiber-Chip-Coupling´ is funded by the BMWi within the funding initiative `ZIM – Zentrales Innovationsprogramm Mittelstand (Central Innovation Program Small and Medium Enterprises)´ with an overall  project budget of 0.59 million €.


Sketch of the assembly aid in blue with inserted optical fibers in red. A photonic chip was exemplarily chosen from the ActPhast project.