Non-linear SiN microresonator boosts on-chip photonics

January 13, 2022 // By Nick Flaherty
Non-linear SiN microresonator boosts on-chip photonics
A new technique using silicon nitride (SiN) microresonators at EPFL boosts the efficiency of generating colours in photonic chips

Researchers in Switzerland have developed a new principle for introducing second-order optical nonlinearity into silicon nitride chips.

The team from the Photonic Systems Laboratory at EPFL, headed by Professor Camille Brès, induced nonlinearity to convert light where it is not normally possible to do so, for example producing different colours. The silicon nitride resonators developed at EPFL and commercialized by Ligentec in a standard CMOS process, exhibit very low losses so that light circulates in resonators for a very long time.

"When using a green laser pointer for example, the laser itself is not green because these are particularly difficult to manufacture. So we change the frequency of an existing laser. It emits at a frequency which is half that of green, then we double it by using nonlinearity in a crystal which gives us green,” said Prof Brès.

“Our study consists of integrating this functionality but on chips that can be manufactured with standard CMOS techniques developed for electronics. Thanks to this, we will be able to efficiently generate different colours of light on a chip.”

Current photonic chips compatible with CMOS processes use standard photonic materials, such as silicon, which do not possess second-order nonlinearity and therefore are not inherently capable of transforming light in this way. “This turns out to be a barrier to the advancement of technology,” said Brès.

“Non-linearity comes from the interaction between light and matter. This exchange must be long if the process is to be functional and efficient. However, the chip is a small object on which we do not benefit from long distances” said researcher Dr Edgars Nitiss. The light introduced into the resonator is captured and travels the time necessary for the nonlinear interaction to be increased.

This technique boosts the efficiency of the optically reconfigurable quasi-phase-matching in the large-radius silicon nitride microresonators to 47.6 percent/W but imposes a new constraint. “When using a resonator, we are limited in terms of

Vous êtes certain ?

Si vous désactivez les cookies, vous ne pouvez plus naviguer sur le site.

Vous allez être rediriger vers Google.