Photonic integration is a growing field; in comparison to electronics, the field of photonics, in which waveguides and devices are produced as an integrated system onto a flat wafer, is relatively new. Because photonic integration is less costly and easier to manufacture, it has concentrated on communications applications previously constructed on silicon devices.
Researchers are looking on novel waveguide technologies that might give similar benefits for applications in the ultraviolet to the infrared band. These systems open up a considerably wider range of applications, including chemical sensing spectroscopy, precision metrology, and computing.
A study published by AIP Publishing in the journal APL Photonics gives an overview of the area of ultra-wideband photonic waveguide systems based on wide bandgap semiconductors. With these waveguides and integrated circuits, important components of ultra-high-performance systems may be moved to the chip size rather than massive tabletop devices in a lab, resulting in power-efficient, compact solutions.
Key components and subsystems for applications like atomic clocks, quantum communications, and high-resolution spectroscopy have traditionally been built in racks and on tabletops. This was important because, among other things, they operate at wavelengths that are not accessible to silicon waveguides because to their smaller bandgap and other absorption qualities in the UV to near-IR, which restrict optical power handling capabilities.
Now that the silicon market has been addressed for telecommunications and LIDAR applications, we are exploring new materials that support an exciting variety of new applications at wavelengths not accessible to silicon waveguides.Daniel J. Blumenthal
Photonic integration systems based on waveguides constructed with broad bandgap semiconductors with ultralow propagation losses have been investigated by Daniel J. Blumenthal and his colleagues in Santa Barbara, California.
“Now that the silicon market has been addressed for telecommunications and LIDAR applications, we are exploring new materials that support an exciting variety of new applications at wavelengths not accessible to silicon waveguides,” said Blumenthal. “We found the most promising waveguide platforms to be silicon nitride, tantala (tantalum pentoxide), aluminum nitride, and alumina (aluminum oxide).”
Each platform has the ability to address distinct applications, such as visible to near-IR atomic transitions in silicon nitride, raman spectroscopy in tantalum pentoxide, and UV interactions with atoms in aluminum oxide for quantum computing.
Putting functionalities like ultralow linewidth lasers on lightweight, low-power devices can help applications like atomic clocks in satellites and next-generation high-capacity data center interconnects. As data center capacity grows, standard fiber interconnects reach their power and space limits, this is an area of significant interest.
Next-generation photonic integration, according to Blumenthal, would necessitate ultra-wideband photonic circuit platforms that scale from UV to IR, as well as a broad set of linear and nonlinear circuit functionalities, ultralow loss, and high-power handling capabilities.