Great circle solution to polarization-based quantum communication (QC) in optical fiber

A polarization encoded receiver, comprising:

• a first detector associated with an SOP in a first basis;
• a second detector associated with an SOP in a second basis conjugate to the first basis;
• and
• a first polarization controller configured to selectively adjust a received optical flux having SOPs in two bases into a first adjusted optical flux, wherein components of the first adjusted optical flux have an SOP in the first basis;
• and
• a second polarization controller configured to further adjust at least a portion of the first adjusted optical flux from the first polarization controller into a second adjusted optical flux, wherein components of the second adjusted optical flux have an SOP in the second basis.

A quantum communication method, comprising:

• receiving a polarization encoded optical data flux associated with at least two orthogonal bases;
• adjusting, at a first polarization controller, the received flux into a first adjusted optical flux, wherein components of the first adjusted optical flux have SOPs in a first pre-determined basis;
• further adjusting, at a second polarization controller, at least a portion of the first adjusted optical flux into a second adjusted optical flux, wherein components of the second adjusted optical flux have SOPs in a second pre-determined basis;
• directing the first adjusted optical flux to a first detector associated with an SOP in the first pre-determined basis;
• and
• directing the second adjusted optical flux to a second detector associated with an SOP in the second pre-determined basis.

A transmitter, comprising:

• a laser configured to produce an optical flux;
• a polarization modulator configured to modulate the optical flux so as to encode data in at least two orthogonal polarization bases;
• and
• a polarization control system configured to adjust the modulated optical flux into an adjusted optical flux based on input received from a remote receiver so that the adjusted optical flux has polarization bases different than those associated with the optical flux.