US Patent 10185153 Orthogonal optical path length extender

A system to adjust light path length comprising a digital light path length modulator is described. The digital light path length modulator comprises a polarization modulator to receive polarized light and to modulate a polarization of some or all of the polarized light, and an optical path length extender (OPLE) to direct the light entering the OPLE with a first polarization along a first light path through the OPLE, and to direct the light entering the OPLE with a second polarization along a second light path through the OPLE, the second light path through the OPLE having a light path length longer than the first light path length through the OPLE.