The optical properties of the liquid-crystal analogue of the Abrikosov phase, the TGB_A phase, have been examined for the first time using the Kossel technique. The Kossel diagrams observed between crossed polarizers each consist of a bright annulus on which a darker spiral pattern is superimposed. Identical patterns have been reported and explained previously for the chiral nematic phase and the results presented here indicate that the optics of the TGB_A phase are analogous to those of the cholesteric phase. Both the pitch and handedness of the TGB_A phase have been measured from the Kossel diagrams. The pitch of the material was found to be approximately linear with temperature, ranging from around 550 nm at the TGB_A-to-SmC*_α phase boundary to 450 nm at the TGB_A-to-isotropic phase boundary.