Progress Toward a Three-Node Multispecies Ion Trap Quantum Network*

To address the challenge of scaling trapped ion quantum computing systems, we utilize a modular architecture consisting of separate traps, each containing $^{171}$Yb$^+$ memory qubits and $^{138}$Ba$^+$ communication qubits. Single photons from the Ba$^+$ ions provide links between nodes of the network for remote entanglement. The main challenge in this system is achieving high remote entanglement generation rates. Here we present the design of and progress toward construction of a three-node network with increased modularity and nearly quadrupled potential photon collection rates. In particular, we focus on the design and testing of in-vacuum high numerical aperture (NA=0.8) aspheric lenses as replacements for our current NA=0.6 multi-component objective. Additionally, we discuss a protocol for generating full remote entanglement among three traps utilizing both atomic species.