Like single mode fiber, polarization maintaining (PM) fiber supports single spatial mode for the designed wavelength. Unlike single mode fiber though, PM fiber maintains a linear polarization state when linearly polarized light is launched along its fast or slow axis. The two axes are defined based on the speed light propagates along them. The speed difference is caused by the stress-applying members. In the case of the popular PANDA fiber, the slow axis is essentially the line linking the two stress members.

In general, PM fibers cannot be used as polarizers. However, when the optical wavelength falls between the cut-off wavelength of the fast and the slow axes, some polarizing effect can be observed. For a more in-depth discussion on PM fiber, go to our “Learning” page for PM fiber termination/connectorization. Besides PM fiber assemblies, we also offer multiple fiber assemblies for single mode and multimode fibers.