Abstract: The disclosed Quantum Optical Coherence Tomography apparatus and method includes a source of quantum entangled photons and a quantum interference device. The pair of entangled photons is divided into two beams, one of which illuminates a semi-reflective object and the second of which is reflected from a variable optical time-delay element (VTE). The VTE is scanned and the quantum interference in the QID is recorded to build up a reflectance profile of the object. Areal scanning produces a full tomographic reflectance image. A method of processing the data to eliminate the effects of optical dispersion is disclosed.

Abstract: The invention relates to an entangled-photon apparatus capable of measuring particular characteristics of an optical element, device or channel and further capable of correcting for the effects of said characteristics in an optical communications signal propagating through the optical element. Specifically, the apparatus and a method of using said apparatus to measure and compensate polarization mode dispersion in an optical communications fiber is disclosed. The apparatus includes a source of entangled photons, which are injected into the device under test along with the communications signal, and a two branch quantum interference device (QID) for determining the state of entanglement of said photons after they pass through the device. The quantum interference device includes a variable, polarization-specific delay element that is incremented to equalize the twinon correlation in the two branches of the QID, and a second variable delay element to apply the compensation to the communications signal.

Abstract: The invention relates to an entangled-photon apparatus capable of measuring particular characteristics of an optical element, device or channel. Specifically, the apparatus and a method of using said apparatus to measure polarization mode dispersion in an optical communications fiber is disclosed. The apparatus includes a source of entangled photons, which are injected into the device under test, and a quantum interference device for determining the state of entanglement of said photons after they pass through the device. The quantum interference device includes a variable, polarization-specific delay element that is incremented to null out polarization mode dispersion in the device under test, and a wavelength demultiplexer/array detector that permits simultaneous measurements across a wide wavelength band.