Researchers Create Ultralow-Loss Silicon Nitride Integrated Photonic Circuits

Scientists from EPFL have developed ultralow-loss silicon nitride integrated circuits (ICs). ICs of this sort are critical for photonic devices such as chip-scale frequency combs, narrow-linewidth lasers, coherent lidar, and neuro-morphic computing, among other uses. This type of IC can encode information into light to be transmitted through optical fibers and is described as a core component of optical communications.

The IC created by the EPFL team has a loss of 1 dB/m, record value for nonlinear integrated photonic material. The researchers say that ultralow loss of this type is essential for integrated photonics allowing for the synthesis, processing, and detection of optical signals using on-chip waveguides. Such low loss will reduce the power budget for building chip-scale optical frequency combs used in several applications.

The new technology can build silicon nitride integrated photonic circuits at record low optical losses and small footprints. The new technology was used to develop meter-long waveguides on a 5x5 square mm chip using high-quality-factor microresonators. Researchers also report their technique has a high fabrication yield said to be essential for industrial production.

Optical frequency cones are used in applications including coherent optical transceivers, low-noise microwave synthesizers, LiDAR, neuromorphic fixed computing, and optical atomic clocks. Researchers on the project note they are looking forward to seeing their chip devices used in emerging applications, including coherent LiDAR, photonic neural networks, and quantum computing. Chips of this sort are typically made from silicon, but this chip breakthrough is based on silicon nitride. It's unclear at this time when the new ICs might be integrated into commercially available products.