GoKawiilLindell Williams (left) and Grant Brodnik align an optical fiber with the edge of an integrated photonics chip. Optical fibers act as pipes for light, enabling the light generated on these chips to be collected and routed off the chip for use in experiments and applications. Credit: R. Jacobson/NIST
Computer chips that cram billions of electronic devices into a few square inches have powered the digital economy and transformed the world. Scientists may be on the cusp of launching a similar technological revolution — this time using light.
In a significant advance toward that goal, National Institute of Standards and Technology (NIST) scientists and collaborators have pioneered a way to make integrated circuits for light by depositing complex patterns of specialized materials onto silicon wafers. These so-called photonics chips use optical devices such as lasers, waveguides, filters and switches to shuttle light around and process information. The new advance could provide a big boost for emerging technologies such as artificial intelligence, quantum computers and optical atomic clocks.
Making circuitry for light as powerful and ubiquitous as circuitry for electrons is one of today’s technological frontiers, says Scott Papp, a NIST physicist whose group led the research, published this week in Nature. “We’re learning to make complex circuits with many functions, cutting across many application areas.”
Light Speed
When it comes to information transfer and processing, light can do things that electricity can’t. Photons — particles of light — are far zippier than electrons at working their way through circuits.
Laser light is also essential for controlling powerful, emerging quantum technologies such as optical atomic clocks and quantum computers.
But several hurdles remain before integrated photonics can truly hit its stride. One involves lasers. High-quality, compact and efficient lasers exist in only a few wavelengths, or colors, of light. For example, semiconductor lasers are very good at generating infrared light with a wavelength of 980 nanometers, or billionths of a meter — a color just outside the range of human vision.
Emerging technologies such as optical atomic clocks and quantum computers need laser light in many other colors as well. The lasers that produce those colors are big, costly and power-hungry, effectively confining these quantum technologies to a handful of special-purpose labs.
By integrating lasers into circuits on chips, scientists hope to help quantum technologies become cheaper and more portable, so they can start to fulfill their vast promise.
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