Improved N-port optical quasi-circulator by using a pair of orthogonal holographic spatial- and polarization- modules.

Based on the flexibilities of light beam propagation in three dimensions, we propose an improved N-port optical quasi-circulator by using a pair of orthogonal holographic spatial- and polarization- modules. All optical elements are located in parallel planes that are perpendicular to the optical axis. The number of optical elements is decreased, and a higher performance optical quasi-circulator without crosstalk and polarization mode dispersion can be easily achieved. A prototype of 5-port polarizationindependent optical quasi-circulator operating at a wavelength of 1300nm was assembled and tested to show its validities.