Quantum scientists worldwide are striving to improve quantum computers, making them more reliable and powerful. DDS technology plays a crucial role in this advancement. The German start-up eleQtron offers groundbreaking quantum computers that use microwave radiation instead of lasers to control individual trapped-ion qubits. This approach simplifies the system design while significantly reducing cooling and power requirements. This major step is made possible by Arbitrary Waveform Generators (AWGs) from Spectrum Instrumentation, which employ advanced Direct Digital Synthesis (DDS) technology. These AWGs can generate up to 20 sine wave carriers per output, enabling precise quantum operations.
EleQtron, a spin-off from the University of Siegen, recently delivered a quantum computer implementing their patented MAGIC (MAgnetic Gradient Induced Coupling) quantum processors. Unlike conventional designs, MAGIC uses microwave radiation rather than lasers to manipulate qubits.
Initially, laser ablation in a high vacuum creates a string of Ytterbium (¹⁷¹Yb⁺) ions. This process can generate a register of up to 30 ions, each functioning as a qubit. Quantum algorithms rely on a combination of a magnetic field and an oscillating electric field to generate a Paul trap (quadrupole ion trap). Traditional designs use lasers at this stage to control qubits, requiring extremely precise targeting and high power.
By contrast, microwaves are technically simpler and consume roughly one-fifth of the power. A high-frequency oscillator combined with Spectrum’s DDS card through a single-sideband (SSB) mixer generates signals around 12.64 GHz. Thanks to the Zeeman effect from the magnetic field, each ion can be individually addressed by modulating the signal in 3–5 MHz increments. This provides low crosstalk and integrates seamlessly with chip-based ion traps. The DDS card generates the multi-tone signal required for individual qubit control and manipulation.
EleQtron’s quantum computers use multiple MAGIC processors. When the team reached the limits of their existing AWG hardware, they turned to Spectrum Instrumentation. Signals must be precisely modified in amplitude, phase, pulse length, and frequency to achieve the correct Rabi frequency, which determines the speed of quantum operations. These requirements place high demands on the AWG.
Among quantum scientists, the Spectrum Instrumentation M4i.6631 AWG is a bestseller, capable of generating virtually any waveform. In DDS mode, the card can produce up to 20 independent sine wave carriers per channel, allowing fast and efficient experiment control.
EleQtron was recommended the M4i.66xx series of 16-bit AWGs, a trusted instrument line among quantum researchers worldwide. These PCIe cards offer one, two, or four synchronous channels with output rates up to 1.25 GS/s and a large onboard memory that can be segmented to replay different waveforms. With Spectrum’s optimized drivers, data transfer rates of 2.8 GB/s are achievable, and up to eight cards can be synchronized if necessary. The additional DDS firmware allows up to 20 sine wave cores per channel, each programmable in frequency, amplitude, phase, and slope, with ultrafast 6.4 ns resolution. This capability enables control of more qubits and provides the flexibility needed to implement complex quantum circuits.
For the eleQtron team, the DDS solution was pivotal to their concept. They also highlighted the outstanding support from Spectrum, from detailed documentation to rapid responses from the design engineers.
