A Mach-Zehnder interferometer for the detection and noninvasive optical amplification of polarization rotation

We present the theory and design of a Mach-Zehnder interferometer with orthogonally polarized arms that passively, noninvasively, optically amplifies polarization rotation in one arm of the interferometer. Theoretical analysis of the electric fields in the two arms is used to compare the significance of device optimizations. Design of the beam alignment, beam recombination, noise isolation, and active stabilization to enable reliable measurements are thoroughly discussed. Finally, we review a comparison between the interferometer with an optical gain factor of approximately 4.5 and the optical bridge (OB) technique for polarization rotation detection that shows the interferometer offers better performance than the OB.