Integrated Silicon Nitride Photonic Chips

Built-in silicon nitride photonic chips with meter-long spiral waveguides. Credit score: Jijun He, Junqiu Liu (EPFL)

Encoding data into gentle, and transmitting it by way of optical fibers lies on the core of optical communications. With an extremely low lack of 0.2 dB/km, optical fibers created from silica have laid the foundations of at this time’s international telecommunication networks and our data society.

Such ultralow optical loss is equally important for built-in photonics, which allow the synthesis, processing and detection of optical indicators utilizing on-chip waveguides. At present, quite a lot of modern applied sciences are primarily based on built-in photonics, together with semiconductor lasers, modulators, and photodetectors, and are used extensively in knowledge facilities, communications, sensing and computing.

Built-in photonic chips are often created from silicon that’s considerable and has good optical properties. However silicon can’t do all the pieces we’d like in built-in photonics, so new materials platforms have emerged. Considered one of these is silicon nitride (Si3N4), whose exceptionally low optical loss (orders of magnitude decrease than that of silicon), has made it the fabric of alternative for purposes for which low loss is important, reminiscent of narrow-linewidth lasers, photonic delay strains, and nonlinear photonics.

Now, scientists within the group of Professor Tobias J. Kippenberg at EPFL’s College of Primary Sciences have developed a brand new expertise for constructing silicon nitride built-in photonic circuits with document low optical losses and small footprints. The work is revealed in Nature Communications.

Combining nanofabrication and materials science, the expertise is predicated on the photonic Damascene course of developed at EPFL. Utilizing this course of, the group made built-in circuits of optical losses of just one dB/m, a document worth for any nonlinear built-in photonic materials. Such low loss considerably reduces the facility funds for constructing chip-scale optical frequency combs (“microcombs”), utilized in purposes like coherent optical transceivers, low-noise microwave synthesizers, LiDAR, neuromorphic computing, and even optical atomic clocks. The group used the brand new expertise to develop meter-long waveguides on 5×5 mm2 chips and high-quality-factor microresonators. In addition they report excessive fabrication yield, which is important for scaling as much as industrial manufacturing.

“These chip gadgets have already been used for parametric optical amplifiers, narrow-linewidth lasers and chip-scale frequency combs,” says Dr. Junqiu Liu who led the fabrication at EPFL’s Middle of MicroNanoTechnology (CMi). “We’re additionally trying ahead to seeing our expertise getting used for rising purposes reminiscent of coherent LiDAR, photonic neural networks, and quantum computing.”

Reference: “Excessive-yield, wafer-scale fabrication of ultralow-loss, dispersion-engineered silicon nitride photonic circuits” by J. Liu, G. Huang, R. N. Wang, J. He, A. S. Raja, T. Liu, N. J. Engelsen and T. J. Kippenberg, 16 April 2021, Nature Communications.
DOI: 10.1038/s41467-021-21973-z

By Rana

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