Quantum communication systems having dispersion compensating optical fiber links

A quantum key generation system comprising:

• a dispersion compensating optical fiber link extending between and optically coupling a photonic quantum bit generator and a photon detector unit, wherein:
• the dispersion compensating optical fiber link comprises a core and a cladding surrounding the core and is structurally configured to induce dispersion of a photon comprising a wavelength of about 1550 nm at an absolute dispersion rate of about 9 ps/(nm)km or less and induce attenuation of the photon comprising the wavelength of about 1550 nm at an attenuation rate of about 0.18 dB/Km or less such that quantum key bit information of a plurality of photons output by the photonic quantum bit generator is receivable at the photon detector unit at a bit rate of at least about 10 Gbit/sec;
• the cladding comprises a first cladding portion, a second cladding portion, and a cladding ring disposed between the first cladding portion and the second cladding portion;
• and
• the core comprises a relative refractive index Δ1, the first cladding portion comprises a relative refractive index Δ2 and the cladding ring comprises a relative refractive index Δ3, where Δ1>Δ3>Δ2.

A quantum key generation system comprising

• two photon entanglement chains,
• a plurality of dispersion compensating optical fiber links;
• and
• two photon detector units;
• wherein:
• each photon entanglement chain extends between the two photon detector units;
• each photon entanglement chain comprises at least one photonic quantum bit generator and first and second terminating quantum memories optically coupled using the plurality of dispersion compensating optical fiber links;
• the first and second terminating quantum memories are positioned at first and second ends of the photon entanglement chains, respectively;
• the first and second terminating quantum memories of each of the two photon entanglement chains form first and second cross-chain quantum repeaters, respectively, to generate measurable entangled particles at the cross-chain quantum repeaters, and
• the first and the second photon detector units are structurally configured to receive the measurable entangled particles generated by the first and second cross-chain quantum repeaters, respectively;
• the plurality of dispersion compensating optical fiber links comprise a core and a cladding surrounding the core;
• the cladding comprises a first cladding portion, a second cladding portion, and a cladding ring disposed between the first cladding portion and the second cladding portion;
• and
• the core comprises a relative refractive index Δ1, the first cladding portion comprises a relative refractive index Δ2 and the cladding ring comprises a relative refractive index Δ3, where Δ1>Δ3>Δ2.