Chip scale coil stabilized Brillouin laser driving a room temperature trapped ion qubit

Photonic integrated stable, ultra-low-noise lasers are essential for scalable and portable quantum information systems. Trapped ions are a leading modality for quantum computing and optical clocks, with room-temperature operation enabling portable applications. Current systems rely on free-space lasers and stabilization cavities, frequency conversion, and cryogenic infrastructure, limiting size, weight, and power. We demonstrate a chip-scale coil-stabilized 674 nm Brillouin laser driving qubit state preparation and measurement and the optical clock transition in a room-temperature surface electrode trapped ⁸⁸Sr⁺ ion without a bulk-optic reference cavity. The CMOS compatible silicon nitride integrated 3-meter coil and Brillouin laser achieve 8.8×10^-13 stability at 20 ms, sufficient to interrogate the 0.4 Hz quadrupole optical clock transition. The ion-disciplined laser achieves 5.3 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>×</mml:mo><mml:msup><mml:mrow><mml:mn>10</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>13</mml:mn></mml:mrow></mml:msup><mml:mo>/</mml:mo><mml:msqrt><mml:mrow><mml:mi>τ</mml:mi></mml:mrow></mml:msqrt></mml:math> stability, spectroscopy with 1.5 kHz linewidths, and 99.6% qubit state preparation and measurement fidelity. These results light the way towards integration of stabilized lasers with trapped-ion chips for portable and robust quantum technologies.