Since PANDA fiber is a type of SMF, cut-off wavelength and mode field diameter (MFD) are the important properties as well as propagation loss.
Since the distributions of refractive index for X and Y polarized light in the PANDA fiber are different each other, there are a coupled of cut-off wavelengths. For the X polarized light, the equivalent refractive index is higher and the cut-off wavelength is longer. In a typical PANDA fiber, the cut-off wavelength for the X polarized fiber is indicated so as to use either of cut-off wavelengths.
MFD is slightly different between the X and Y polarized light.