Whispering Gallery Modes microcavities on a Si-chip

Whispering Gallery Modes (WGM) microresonators, where the light circulates close to outer surface, exhibit very high Quality-factors (Q) and small mode volumes. They can thus be used in many applications and systems, such as cavity quantum electrodynamics, biochemical sensors, lasers, thermal sensors, and opto-mechanics.


We have developed an expertise in fabricating various silica WGM microcavities on a silicon chip (ring, disk, toroid) using the cleanroom facilities of the "Plateforme Technologique Amont" (PTA). We also realize very small silica microspheres on a chip, a new type of microresonator.

SEM micrographs of a silica microdisk on a Si-chip with a radius of 40 µm, a microtoroid with a radius of 25 µm, and a silica microsphere with a radius of 11.5 µm


In our lab, we measure the optical performances of these cavities by coupling the optical WGM to a tapered optical fiber in the 1500 nm wavelength range. Very high Qs (~108) have been measured on microtoroids and microspheres, truly approaching the state of the art. In our lab, we can also study the coupling of light emitters with WGM by micro-photoluminescence.

Transmission spectrum of a high-Q silica toroidal resonator with a radius of 24 µm.

A splitting of resonance mode of a silica microtoroid with a radius of 33µm in undercoupling regime. The Q-factor is above 0.95×108. The red curve is a dual-Lorentz fit.

Micro-PL spectrum from a Er-doped Silicon-Rich Oxide microsphere on a chip with a radius of 6 µm (UV excitation).



Our research is currently focused on three main areas:


  • Study of an integrated optical angular velocity microsensor based on Sagnac effect. In collaboration with CEA-Leti / DSIS (Grenoble), CNES (Toulouse)





More information on our work in: 



or contact the principal investigator: Jean-Baptiste Jager


Maj : 26/09/2016 (844)


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