AAWSAP DIRD, The Space Communication Implications of Quantum Entanglement and Nonlocality, March 2010

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which are linearly polarized horizontally (HLP) and are transmitted by the splitter. As
Dopfer has shown, because of momentum entanglement, an image of slit system S1 will
be formed by the "e" photons linearly polarized vertically (VLP) at a path length f
beyond the lens on the deflected path at position S2 1 where a pair of "cleanup" slits are
located that pass only those photons whose entangled twins passed through S1. We
note that because of the optical geometry, this imaging occurs even for waves that
pass through both of the image points and ultimately interfere.
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351 nm
Double Convex Lens
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Focal Length = f
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Figure 7. Slit-Imaging Coincidence-Free Version of the Ghost Interference Experiment to Demonstrate
Nonlocal Communication
At the image position of each slit at S2, we place an optical fiber, as shown. The fibers
conduct the light to an optical switch, at which the light either is sent directly to two
avalanche photodiode detectors D (providing which-way information about which of the
S1 slits the photon entered) or alternatively is routed to an optical combiner C, with the
in-phase output of the combiner then detected, so that waves passing through both
slits can contribute constructively to the detection event. We note that this fiber
switching system is the fiber-optic equivalent of a Mach-Zehnder interferometer
(Reference 20), in which one can activate and deactivate the last half-silvered mirror by
switching, so that which-way information can be switched on and off. (We also note
that similar fiber-combiner-detector technology could be employed after the S1 slits to
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Object Slits
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