MacRobends of bow-tie fibres with constant curvature

The letter treats macrobends of bow-tie fibres with constant curvature, using our previously published work as the theoretical building block. In the practical case of unequal core and cladding anisotropy, there exists a single-polarisation window which shifts towards the shorter-wavelength range as the bend radius decreases. Also treated theoretically is the extinction ratio against bend orientation. Unexpectedly, it is found that, if equal core and cladding anisotropy are assumed in the theoretical analysis, then, unlike the ideal case of a straight anisotropic fibre, the differential losses virtually disappear in a bent bow-tie fibre with constant curvature.