Large Scale Integrated Silicon Photonic MEMS Switch Matrix
Fiber-Optics communication systems are the backbone of today’s modern information and telecommuncation infrastructure. Not only on Earth do data centers deal with gigantic volumes of data transmitted through optical fibers, but optical communication is also increasingly relevant in satellite systems. The requirement of these networks to be dynamic in terms of channel interconnections imposes the need for high-port-number optical switches. Ideally, these need to occupy little space, consume low amounts of energy and be light-weight if they are to be set into orbit.
The objective of PHOTON-MIX is the development of a high-port-count, low-mass-and-energy-consumption, fast switch matrix for optical communications in the C-band. The enabling technologies to address simultaneously all these requirements are integrated photonics and latching bistable MEMS switches. The former allow to concentrate a great number of optical devices in a cm-sized silicon microchip, thus providing high number of channels and compactness: low size and weight. The latter make it possible to set the state of each of the switch of the matrix either ON or OFF without the need of maintaining a voltage applied constantly to fix this state: this accounts for low power consumption.
Schematics of a photonic switch matrix.
Cross section of an individual bistable switch.
For the realization of PHOTON-MIX, the team uses the brand new DUV Stepper recently installed at the Centre of Micronanotechnology of EPFL. This tools allows fast photolithography patterning down to 100 nm dimensions. This combined with etching and lift-off processes, among others, allows the fabrication of the many-layer photonic MEMS chips. Thus, a highly integrated 70×70 bistable switch matrix on a 1 cm sided chip is envisaged as the final deliverable.
SEM of a grating coupler patterned with the DUV stepper and plasma dry etching. Grating period: 600 nm.
Funding and partners
PHOTON-MIX is a project funded by the European Space Agency (ESA), run by a consortium formed by the Q-lab at EPFL (main contractor) and Thales Alenia Space CH (TAS-CH, sub-contractor). We also work in close collaboration with PixAPP (Tyndall) and TAS-France. The project started on the May 16th 2019 and has a foreseen duration of 2 years.
