Beam delivery for trapped ion quantum computing systems requires fine control of beam pointing, amplitude, phase, frequency, and pulse timing. I will discuss challenges scaling these systems and describe why visible integrated photonics offers promise.
Atomic ions controlled by laser light are among the leading candidates for large scale quantum computing. However operational systems today require vast scaling to reach levels capable of useful computational tasks. The integration of light delivery will be an essential component of this for the trapped-ion approach. I will describe results in which the use of photonics integrated into ion trap chips has allowed us to perform high fidelity two-qubit gates, which are an essential building block for quantum computers. These systems have now been extended to the operation of multiple trap zones, and the creation of novel optical fields for ion trap control while a new generation of chips allowing integration of all required wavelengths as well as optimised light delivery offers further enhancements in performance and scaling.
Quantinuum has deployed trapped-ion quantum computers based on a quantum charge-coupled (QCCD) architecture exhibiting high-fidelity operations, mid-circuit measurements, and full connectivity with record performance. Quantinuum recently released its accelerated Roadmap outlining plans to reach thousands of physical qubits while further reducing logical qubit error rates in commercial systems by 2029 [1]. Longerterm scaling of the QCCD device architecture will be enabled by replacing bulk free-space optics with integrated photonics for improved light delivery and detection. To this end, Quantinuum is developing integrated photonics technologies at the visible and ultraviolet wavelengths required for future large-scale trapped-ion quantum computers. This poster presents recent developments in materials (waveguiding materials, transparent conductive materials), visible and ultraviolet integrated photonics components for light routing and control, and the various paths to their implementation. These developments are expected to enable scaling towards larger qubit counts while reducing the physical size of the optical control systems.
Integrated optical control of trapped-ion qubits leveraging dielectric waveguides photonics within planar-fabricated trap devices offers routes to scaling the optical control critical to trapped-ion quantum computing. The ultraviolet to infrared functionality required for many atomic systems, the multiple metal layers for large-scale trap arrays, and the long-term interest in integration of active functionality and integrated electronics motivates development of foundry-based platforms for such systems, to facilitate accessibility to the complex fabrication involved. Aside from scaling, utilization of such technology in trapped-ion quantum systems further stands to alleviate limitations on basic physical operations employed in both quantum computing and metrology, which experiments are starting to demonstrate. I will summarize our recent results using phase-stable standing-wave delivery practically enabled by integrated photonic addressing to enhance ground-state laser cooling, which we experimentally demonstrate using trap devices with integrated Al2O3 and Si3N4 waveguides for UV-NIR addressing fabricated in a commercial foundry. I will also discuss relevance of similar ideas to alleviating power requirements in laser-based entangling gates, and work in progress towards experimental realization, including in a 300 mm-wafer foundry platform for such devices in development.