Nonpolarizing edge filters

Multiple half-wave filters can be detuned to provide a nonpolarizing edge at a specific angle of incidence. For the case of quarter-wave layers, an analytic expression for the necessary amount of detuning can be derived. For non-quarter-wave layers, a more empirical design approach is used. The resulting two-material producible designs improve current limitations in wavelength-division multiplex transmission over multimode optical fibers.