Optomechanical reference oscillators

Published : 12 March 2020

Clocks (reference oscillators) are ubiquitous elements in electronic circuits. The arrival of new technologies such as 5G or autonomous vehicles requires a level of performance that is not attainable by commercial clock technologies. One of the most promising routes to improve performance is the development of clocks based on micro-electromechanical (MEMS) resonators at high frequency (1-5 GHz, tens of GHz in the future).

However, it is challenging to build high-performance MEMS resonators in the GHz range, mainly due to the difficulty of detecting their minuscule vibration amplitudes. Recently several groups have demonstrated the possibility of building optomechanical devices in piezoelectric materials. This technology, which was confined to fundamental studies, is now mature enough to evolve towards applications, and solves many of the difficulties involved in the implementation of MEMS clocks in the GHz range.

The objective of the thesis is to develop a MEMS clock based on this novel optomechanical technology. The thesis will take place in the Microsensors Laboratory of the CEA-Leti, in collaboration with the RF Components Laboratory. The Leti is a pioneer in the implementation of on-chip optomechanical and piezoelectric resonators.

The PhD student will work in collaboration with Leti Engineers to design the MEMS resonators and their fabrication process, based on an analytical study and finite-element simulations. Then, the student will have the opportunity to contribute to the fabrication of the devices in clean room. Finally, the student will characterize them in the Leti’s laboratories, to extract their performance and implement a first demonstrator of MEMS clock.

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