  Trapped ions are one of the leading platforms for quantum information
processing, exhibiting the highest gate and measurement fidelities of all
contending hardware. In order to realize a universal quantum computer with
trapped ions, independent and parallel control over the state of each qubit is
necessary. The manipulation of individual qubit states in an ion chain via
stimulated Raman transitions generally requires light focused on individual
ions. In this manuscript, we present a novel, guided-light individual
addressing system for hyperfine Ba$^+$ qubits. The system takes advantage of
laser-written waveguide technology, enabled by the atomic structure of Ba$^+$,
allowing the use of visible light to drive Raman transitions. Such waveguides
define the spatial mode of light, suppressing aberrations that would have
otherwise accumulated in a free-space optics set up. As a result, we
demonstrate a nearest neighbour relative intensity crosstalk on the order of
10$^{-4}$, without any active aberration compensation. This is comparable to or
better than other previous demonstrations of individual addressing. At the same
time, our modular approach provides independent and agile control over the
amplitude, frequency, and phase of each channel; combining the strengths of
previous implementations.
