Extended Data Fig. 3: Experimental setup for remote entanglement generation.

a, Nanophotonic cavities (Devices 1 and 2) are cooled by a ³He cryostat to 0.5 K. Optical control of ions’ A and F transitions is achieved using lasers L1, L3 and L4 which are modulated by a series of acousto-optic modulator (AOM) setups for pulse generation and frequency tuning (AOM 3–8). All lasers are frequency-locked to a reference cavity. Photons exiting the devices are combined on a polarizing beamsplitter (PBS 1), AOM 9 routes photons towards the Detection setup (depicted in b). Heterodyne phase measurement of the optical path difference between Devices 1 and 2 is achieved using light pulses from laser L2 which are routed by AOM 9 to an avalanche photodiode (APD) for measurement. b, There are three possible detection setups used for entanglement heralding and readout. Setup 1 consists of a single superconducting nanowire single photon detector (SNSPD) and heralds entanglement of two ions within the same device. Setup 2 uses a single SNSPD combined with a time-delayed interferometer to entangle two ions with different optical frequencies located in separate devices. Setup 3 uses two SNSPDs for entanglement experiments involving more than two ions. c, Setups AOM 5 and 6 each consist of a single AOM in double pass configuration and enable simultaneous, phase-stable driving of ions in the same device. d, Setups AOM 7 and 8 consist of three acousto-optic modulators, each in double pass configuration, enabling pulse generation with a 2π × 600 MHz optical frequency tuning range. e, Microwave setup for driving the ground and excited state spin transitions at ≈ 2π × 675 MHz and ≈ 2π × 3.37 GHz, respectively. The ground state (qubit) pulses are generated by heterodyne modulation combined with filters for image rejection before being amplified, combined with the excited state pulses on a diplexer and sent to the device.