Thursday, April 22, 2021

EPFL develops ultralow-loss integrated photonic circuits

Researchers at the École polytechnique fédérale de Lausanne (EPFL) are developing ultralow-loss integrated photonic circuits based on silicon nitride (Si3N4), whose exceptionally low optical loss are orders of magnitude lower than that of silicon.

The work, which is led by Professor Tobias J. Kippenberg at EPFL’s School of Basic Sciences, has just been published in Nature Communications.

"Combining nanofabrication and material science, the technology is based on the photonic Damascene process developed at EPFL. Using this process, the team made integrated circuits of optical losses of only 1 dB/m, a record value for any nonlinear integrated photonic material. Such low loss significantly reduces the power budget for building chip-scale optical frequency combs (“microcombs”), used in applications like coherent optical transceivers, low-noise microwave synthesizers, LiDAR, neuromorphic computing, and even optical atomic clocks. The team used the new technology to develop meter-long waveguides on 5x5 mm2 chips and high-quality-factor microresonators. They also report high fabrication yield, which is essential for scaling up to industrial production."

“These chip devices 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 Center of MicroNanoTechnology (CMi). “We are also looking forward to seeing our technology being used for emerging applications such as coherent LiDAR, photonic neural networks, and quantum computing.”