New Photonic Chip for Isolating Light May Be Key to Miniaturizing Quantum Devices

October 25, 2021

Oct. 25, 2021 — Light offers an irreplaceable way to interact with our universe. It can travel across galactic distances and collide with our atmosphere, creating a shower of particles that tell a story of past astronomical events. Here on earth, controlling light lets us send data from one side of the planet to the other.

On-chip optical isolators for 780 nm and 1550 nm wavelengths, fabricated in lithium niobate at the University of Illinois Urbana-Champaign.
Image Credit: Ogulcan Orsel.

Given its broad utility, it’s no surprise that light plays a critical role in enabling 21st century quantum information applications. For example, scientists use laser light to precisely control atoms, turning them into ultra-sensitive measures of time, acceleration, and even gravity. Currently, such early quantum technology is limited by size—state-of-the-art systems would not fit on a dining room table, let alone a chip. For practical use, scientists and engineers need to miniaturize quantum devices, which requires re-thinking certain components for harnessing light.

Now IQUIST member Gaurav Bahl and his research group have designed a simple, compact photonic circuit that uses sound waves to rein in light. The new study, published in the October 21 issue of the journal Nature Photonics, demonstrates a powerful way to isolate, or control the directionality of light. The team’s measurements show that their approach to isolation currently outperforms all previous on-chip alternatives and is optimized for compatibility with atom-based sensors.

“Atoms are the perfect references anywhere in nature and provide a basis for many quantum applications,” said Bahl, a professor in Mechanical Science and Engineering (MechSe) at the University of Illinois at Urbana-Champaign. “The lasers that we use to control atoms need isolators that block undesirable reflections. But so far the isolators that work well in large-scale experiments have proved tough to miniaturize.”

Even in the best of circumstances, light is difficult to control—it will reflect, absorb, and refract when encountering a surface. A mirror sends light back where it came from, a shard of glass bends light while letting it through, and dark rocks absorb light and converts it to heat. Essentially, light will gladly scatter every which way off anything in its path. This unwieldy behavior is why even a smidgen of light is beneficial for seeing in the dark.

Controlling light within large quantum devices is normally an arduous task that involves a vast sea of mirrors, lenses, fibers, and more. Miniaturization requires a different approach to many of these components. In the last several years, scientists and engineers have made significant advances in designing various light-controlling elements on microchips. They can fabricate waveguides, which are channels for transporting light, and can even change its color using certain materials. But forcing light, which is made from tiny blips called photons, to move in one direction while suppressing undesirable backwards reflections is tricky.

“An isolator is a device that allows light to pass uninterrupted one way and blocks it completely in the opposite direction,” said the study’s first author Benjamin Sohn, a former graduate student and postdoctoral researcher in Mechse who is now at NIST, Boulder. “This unidirectionality cannot be achieved using just any common dielectric materials or glasses, and so we need to be a little more innovative. We also want the isolator to operate at wavelengths of light tuned to atomic sensors, which can be hard even at large scales.”

In typical experiments, the best tool for achieving unidirectionality uses magnets. For example, nearly every laser has a magneto-optic isolator that lets light exit the laser but prevents it from traveling backwards, which would mess with laser functionality. While even lasers can be miniaturized, shrinking conventional isolators is problematic for two reasons. First, in compact devices, magnetic fields would negatively affect nearby atoms. Second, even if there was a way to get around this, the materials that are inside the isolator do not work as well on the smaller length scales on a chip.

Bahl’s team demonstrated a new non-magnetic isolator that turns out to be simple in design, uses common optical materials, and is easily adaptable for different wavelengths of light.

“We wanted to design a device that naturally avoids loss, and the best way to do that is to have light propagate through nothing. The simplest bit of ‘nothing’ that can still guide photons along a controlled path is a waveguide, which is a very basic component in photonic circuits,” said Bahl.

In a complete atom-based system, the waveguide would steer laser light through a series of elements to a small chamber containing atoms. With this in mind, the team has optimized their chip for use with 780 nanometer light, which is the wavelength needed to configure common rubidium-based sensors.

That is only the first half of the design because for isolation, the light must be simultaneously blocked in the opposite direction. Previously, the team showed that they could launch sound waves into a photonic circuit to break the symmetric flow of light. In the new study the team turned this idea into a demonstration of a functional chip element.

The complete photonic isolator contains a waveguide and an adjacent ring resonator, which looks like an oblong racetrack. Normally, incoming light would just pass from the waveguide into the resonator, irrespective of its direction, thus blocking all light flow. But when the team applied sound waves to the ring, the resonator only captured light that was moving backwards through the waveguide. In the forward direction, light passed through the waveguide unimpeded, as if the resonator was simply not there.

The team’s measurements revealed that nearly every photon moves through the waveguide in the forward direction, while having only one-in-ten-thousand chance of making it through backwards. This means that the design reduced losses, or undesirable light absorption, to nearly zero, which has been a long-standing problem with previous on-chip isolators. The data show that the new devices exhibit record-breaking performance for on-chip isolation and operate as well as the larger magnet-based devices. In addition, the approach is flexible and can used for multiple wavelengths without changing the starting material.

“The simplicity in fabrication is key—with our approach, you could print photonic isolators that work well for whatever wavelength you need, all on the same chip at the same time. This is just not possible with other approaches today,” said co-author Ogulcan Orsel, graduate student in Electrical Engineering at the U of I.

This could make the new design useful for other applications, like quantum computing, where stray, uncontrolled magnetic fields as well as unwanted light can erode overall device performance.

The work was supported by the Defense Advanced Research Projects Agency (DARPA), the Air Force Office of Scientific Research (AFOSR), the National Science Foundation (NSF), and the Office of Naval Research (ONR).

Read Full Paper: Electrically driven optical isolation through phonon-mediated photonic Autler–Townes splitting

Gaurav Bahl, principal investigator.
Donggyu Benjamin Sohn, lead author of the study and former postdoc at University of Illinois. Currently at NIST Boulder.
Ogulcan Emre Orsel, graduate student in Electrical Engineering, co-lead author.


Source: Emily Edwards, University of Illinois Quantum Information Science and Technology

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

Quantinuum Debuts Quantum-based Cryptographic Key Service – Is this Quantum Advantage?

December 7, 2021

Quantinuum – the newly-named company resulting from the merger of Honeywell’s quantum computing division and UK-based Cambridge Quantum – today launched Quantum Origin, a service to deliver “completely unpredicta Read more…

SC21 Was Unlike Any Other — Was That a Good Thing?

December 3, 2021

For a long time, the promised in-person SC21 seemed like an impossible fever dream, the assurances of a prominent physical component persisting across years of canceled conferences, including two virtual ISCs and the virtual SC20. With the advent of the Delta variant, Covid surges in St. Louis and contention over vaccine requirements... Read more…

The Green500’s Crystal Anniversary Sees MN-3 Crystallize Its Winning Streak

December 2, 2021

“This is the 30th Green500,” said Wu Feng, custodian of the Green500 list, at the list’s SC21 birds-of-a-feather session. “You could say 15 years of Green500, which makes it, I guess, the crystal anniversary.” Indeed, HPCwire marked the 15th anniversary of the Green500 – which ranks supercomputers by flops-per-watt, rather than just by flops – earlier this year with... Read more…

AWS Arm-based Graviton3 Instances Now in Preview

December 1, 2021

Three years after unveiling the first generation of its AWS Graviton chip-powered instances in 2018, Amazon Web Services announced that the third generation of the processors – the AWS Graviton3 – will power all-new Amazon Elastic Compute 2 (EC2) C7g instances that are now available in preview. Debuting at the AWS re:Invent 2021... Read more…

Nvidia Dominates Latest MLPerf Results but Competitors Start Speaking Up

December 1, 2021

MLCommons today released its fifth round of MLPerf training benchmark results with Nvidia GPUs again dominating. That said, a few other AI accelerator companies participated and, one of them, Graphcore, even held a separ Read more…

AWS Solution Channel

Running a 3.2M vCPU HPC Workload on AWS with YellowDog

Historically, advances in fields such as meteorology, healthcare, and engineering, were achieved through large investments in on-premises computing infrastructure. Upfront capital investment and operational complexity have been the accepted norm of large-scale HPC research. Read more…

HPC Career Notes: December 2021 Edition

December 1, 2021

In this monthly feature, we’ll keep you up-to-date on the latest career developments for individuals in the high-performance computing community. Whether it’s a promotion, new company hire, or even an accolade, we’ Read more…

Quantinuum Debuts Quantum-based Cryptographic Key Service – Is this Quantum Advantage?

December 7, 2021

Quantinuum – the newly-named company resulting from the merger of Honeywell’s quantum computing division and UK-based Cambridge Quantum – today launched Q Read more…

SC21 Was Unlike Any Other — Was That a Good Thing?

December 3, 2021

For a long time, the promised in-person SC21 seemed like an impossible fever dream, the assurances of a prominent physical component persisting across years of canceled conferences, including two virtual ISCs and the virtual SC20. With the advent of the Delta variant, Covid surges in St. Louis and contention over vaccine requirements... Read more…

The Green500’s Crystal Anniversary Sees MN-3 Crystallize Its Winning Streak

December 2, 2021

“This is the 30th Green500,” said Wu Feng, custodian of the Green500 list, at the list’s SC21 birds-of-a-feather session. “You could say 15 years of Green500, which makes it, I guess, the crystal anniversary.” Indeed, HPCwire marked the 15th anniversary of the Green500 – which ranks supercomputers by flops-per-watt, rather than just by flops – earlier this year with... Read more…

Nvidia Dominates Latest MLPerf Results but Competitors Start Speaking Up

December 1, 2021

MLCommons today released its fifth round of MLPerf training benchmark results with Nvidia GPUs again dominating. That said, a few other AI accelerator companies Read more…

At SC21, Experts Ask: Can Fast HPC Be Green?

November 30, 2021

HPC is entering a new era: exascale is (somewhat) officially here, but Moore’s law is ending. Power consumption and other sustainability concerns loom over the enormous systems and chips of this new epoch, for both cost and compliance reasons. Reconciling the need to continue the supercomputer scale-up while reducing HPC’s environmental impacts... Read more…

Raja Koduri and Satoshi Matsuoka Discuss the Future of HPC at SC21

November 29, 2021

HPCwire's Managing Editor sits down with Intel's Raja Koduri and Riken's Satoshi Matsuoka in St. Louis for an off-the-cuff conversation about their SC21 experience, what comes after exascale and why they are collaborating. Koduri, senior vice president and general manager of Intel's accelerated computing systems and graphics (AXG) group, leads the team... Read more…

Jack Dongarra on SC21, the Top500 and His Retirement Plans

November 29, 2021

HPCwire's Managing Editor sits down with Jack Dongarra, Top500 co-founder and Distinguished Professor at the University of Tennessee, during SC21 in St. Louis to discuss the 2021 Top500 list, the outlook for global exascale computing, and what exactly is going on in that Viking helmet photo. Read more…

SC21: Larry Smarr on The Rise of Supernetwork Data Intensive Computing

November 26, 2021

Larry Smarr, founding director of Calit2 (now Distinguished Professor Emeritus at the University of California San Diego) and the first director of NCSA, is one of the seminal figures in the U.S. supercomputing community. What began as a personal drive, shared by others, to spur the creation of supercomputers in the U.S. for scientific use, later expanded into a... Read more…

IonQ Is First Quantum Startup to Go Public; Will It be First to Deliver Profits?

November 3, 2021

On October 1 of this year, IonQ became the first pure-play quantum computing start-up to go public. At this writing, the stock (NYSE: IONQ) was around $15 and its market capitalization was roughly $2.89 billion. Co-founder and chief scientist Chris Monroe says it was fun to have a few of the company’s roughly 100 employees travel to New York to ring the opening bell of the New York Stock... Read more…

Enter Dojo: Tesla Reveals Design for Modular Supercomputer & D1 Chip

August 20, 2021

Two months ago, Tesla revealed a massive GPU cluster that it said was “roughly the number five supercomputer in the world,” and which was just a precursor to Tesla’s real supercomputing moonshot: the long-rumored, little-detailed Dojo system. Read more…

Esperanto, Silicon in Hand, Champions the Efficiency of Its 1,092-Core RISC-V Chip

August 27, 2021

Esperanto Technologies made waves last December when it announced ET-SoC-1, a new RISC-V-based chip aimed at machine learning that packed nearly 1,100 cores onto a package small enough to fit six times over on a single PCIe card. Now, Esperanto is back, silicon in-hand and taking aim... Read more…

US Closes in on Exascale: Frontier Installation Is Underway

September 29, 2021

At the Advanced Scientific Computing Advisory Committee (ASCAC) meeting, held by Zoom this week (Sept. 29-30), it was revealed that the Frontier supercomputer is currently being installed at Oak Ridge National Laboratory in Oak Ridge, Tenn. The staff at the Oak Ridge Leadership... Read more…

AMD Launches Milan-X CPU with 3D V-Cache and Multichip Instinct MI200 GPU

November 8, 2021

At a virtual event this morning, AMD CEO Lisa Su unveiled the company’s latest and much-anticipated server products: the new Milan-X CPU, which leverages AMD’s new 3D V-Cache technology; and its new Instinct MI200 GPU, which provides up to 220 compute units across two Infinity Fabric-connected dies, delivering an astounding 47.9 peak double-precision teraflops. “We're in a high-performance computing megacycle, driven by the growing need to deploy additional compute performance... Read more…

Intel Reorgs HPC Group, Creates Two ‘Super Compute’ Groups

October 15, 2021

Following on changes made in June that moved Intel’s HPC unit out of the Data Platform Group and into the newly created Accelerated Computing Systems and Graphics (AXG) business unit, led by Raja Koduri, Intel is making further updates to the HPC group and announcing... Read more…

Intel Completes LLVM Adoption; Will End Updates to Classic C/C++ Compilers in Future

August 10, 2021

Intel reported in a blog this week that its adoption of the open source LLVM architecture for Intel’s C/C++ compiler is complete. The transition is part of In Read more…

Killer Instinct: AMD’s Multi-Chip MI200 GPU Readies for a Major Global Debut

October 21, 2021

AMD’s next-generation supercomputer GPU is on its way – and by all appearances, it’s about to make a name for itself. The AMD Radeon Instinct MI200 GPU (a successor to the MI100) will, over the next year, begin to power three massive systems on three continents: the United States’ exascale Frontier system; the European Union’s pre-exascale LUMI system; and Australia’s petascale Setonix system. Read more…

Leading Solution Providers

Contributors

Hot Chips: Here Come the DPUs and IPUs from Arm, Nvidia and Intel

August 25, 2021

The emergence of data processing units (DPU) and infrastructure processing units (IPU) as potentially important pieces in cloud and datacenter architectures was Read more…

D-Wave Embraces Gate-Based Quantum Computing; Charts Path Forward

October 21, 2021

Earlier this month D-Wave Systems, the quantum computing pioneer that has long championed quantum annealing-based quantum computing (and sometimes taken heat fo Read more…

HPE Wins $2B GreenLake HPC-as-a-Service Deal with NSA

September 1, 2021

In the heated, oft-contentious, government IT space, HPE has won a massive $2 billion contract to provide HPC and AI services to the United States’ National Security Agency (NSA). Following on the heels of the now-canceled $10 billion JEDI contract (reissued as JWCC) and a $10 billion... Read more…

The Latest MLPerf Inference Results: Nvidia GPUs Hold Sway but Here Come CPUs and Intel

September 22, 2021

The latest round of MLPerf inference benchmark (v 1.1) results was released today and Nvidia again dominated, sweeping the top spots in the closed (apples-to-ap Read more…

Ahead of ‘Dojo,’ Tesla Reveals Its Massive Precursor Supercomputer

June 22, 2021

In spring 2019, Tesla made cryptic reference to a project called Dojo, a “super-powerful training computer” for video data processing. Then, in summer 2020, Tesla CEO Elon Musk tweeted: “Tesla is developing a [neural network] training computer... Read more…

Three Chinese Exascale Systems Detailed at SC21: Two Operational and One Delayed

November 24, 2021

Details about two previously rumored Chinese exascale systems came to light during last week’s SC21 proceedings. Asked about these systems during the Top500 media briefing on Monday, Nov. 15, list author and co-founder Jack Dongarra indicated he was aware of some very impressive results, but withheld comment when asked directly if he had... Read more…

2021 Gordon Bell Prize Goes to Exascale-Powered Quantum Supremacy Challenge

November 18, 2021

Today at the hybrid virtual/in-person SC21 conference, the organizers announced the winners of the 2021 ACM Gordon Bell Prize: a team of Chinese researchers leveraging the new exascale Sunway system to simulate quantum circuits. The Gordon Bell Prize, which comes with an award of $10,000 courtesy of HPC pioneer Gordon Bell, is awarded annually... Read more…

Quantum Computer Market Headed to $830M in 2024

September 13, 2021

What is one to make of the quantum computing market? Energized (lots of funding) but still chaotic and advancing in unpredictable ways (e.g. competing qubit tec Read more…

  • arrow
  • Click Here for More Headlines
  • arrow
HPCwire