  We present a theoretical investigation of the electronic and optical
properties of V- and T-shaped quantum wires. Valence band mixing as well as
realistic sample geometries are fully included through an accurate and
efficient approach that is described here in detail. We investigate the
resulting valence band structure, which shows some significant peculiarities,
such as an anomalously large spin splitting in the lowest heavy hole subband of
T-shaped wires. For both classes of wires we obtain good agreement between
calculated optical absorption and recent experimental spectra, and we
demonstrate that the analysis of optical anisotropy can be used as an effective
tool to extract information on valence states, usually very difficult to obtain
otherwise.
