  A bulk-optics, polarization-independent phase shifter for photonic quantum
information applications is demonstrated. A transverse mode electro-optic
modulator using lithium niobate is placed in a Sagnac-like loop containing
Faraday rotators. This direction-dependent polarization rotation in the loop is
combined with a Mach-Zehnder interferometer to form an optical switch with an
on/off contrast of 96% and a switching time of 1.6 ns.
