An apparatus for detecting an optical signal emissions includes signal transmission fibers. Each fiber includes cores having the same spatial core arrangement at each end. The first ends are configured to be optically coupled to the signal emission sources. Each fiber is configured to transmit an optical signal between the first end and the second. The apparatus can also include a frame assembly securing the first ends of the fibers in a first spatial fiber arrangement corresponding to a spatial arrangement of the signal emission sources. The frame assembly can also secure the second ends of the fibers in a second spatial fiber arrangement different from the first spatial fiber arrangement. The apparatus can also include at least one signal detector configured to be optically coupled to the second ends of the fibers, and configured to detect an optical signal emitted by each signal emission source.