A system or a method for optical signal amplification includes determining a target operating gain of an optical amplifier; determining a target maximum gain of the optical amplifier; determining an active fiber section length such that the optical signals are amplified with at most the target maximum gain; determining a core cross-sectional area size of the active fiber section based on a maximum allowable pulse shape distortion and a target maximum energy per pulse such that high-energy pulses with the target maximum energy per pulse are distorted by at most the maximum allowable pulse shape distortion; and determining an operating pumping power of the pumping device below the maximum pumping power such that the optical signals are amplified with the target operating gain.

A method for quantum key distribution includes determining a ratio between a target maximum gain and a target operating gain of an optical amplifier; determining an active fiber section length such that the optical signals with a target maximum signal power are amplified with at most the target maximum gain; determining an operating pumping power of a pumping device below the maximum pumping power such that the optical signals are amplified with a target operating gain according to the determined ratio between the target maximum gain and the target operating gain; and determining a shared key between a first data processing device and a second data processing device by quantum key distribution comprising amplifying the optical signals via the optical amplifier by operating the pumping device at the operating pumping power.

A quantum communication system for encrypting communication includes a processor configured to receive an encryption request from a mobile device. The mobile device determines a first encryption key from the mobile device. A quantum random number generator generates a second encryption key using quantum mechanics. The processor transmits the second encryption key to the mobile device. The mobile device implements a digital XOR logic gate configured to perform an XOR operation on the first encryption key and the second encryption key to generate a third encryption key.

Disclosed is a method that includes receiving, at a scheduling server, a request for a first particle of a pair of quantum entangled particles and a second particle of the pair of quantum entangled particles, evaluating the request based on one or more parameters to yield a schedule and communicating instructions from the scheduling server to an entangled particle production system to deliver, according to the schedule, the first particle to a first node and to deliver the second particle to a second node according to the request. In this manner, respective particles of a quantum entangled pair can be delivered to the appropriate nodes for use in a communication.

A quantum key generation system including two photon detector units, two photon entanglement chains extending between the two photon detector units, and a plurality of multicore fiber links each including at least two non-uniform cores structurally configured to provide non-uniform photon propagation delay. Each photon entanglement chain includes at least one quantum repeater structurally configured to entangle a pair of photons and first and second terminating quantum memories optically coupled the quantum repeater using the multicore fiber links such that photons received by the first and the second terminating quantum memories are entangled with photons entangled by the quantum repeater. The first and second terminating quantum memories of each of the two photon entanglement chains form first and second 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.

A quantum cryptographic communication control device includes a collection unit, a calculation unit, a guarantee unit, and a selection unit. The collection unit collects link information of a link for which a local key is generated by quantum key distribution and a global key guarantee amount expected for a pair of applications that perform cryptographic communication by using a global key. The calculation unit calculates a link cost used for selecting a route of the global key based on the link information. The guarantee unit calculates an amount that can be guaranteed for a local key used in the link so as to satisfy the global key guarantee amount. The selection unit selects the route of the global key based on the link cost and the amount that can be guaranteed.

A quantum key distribution system is provided. The quantum key distribution system includes a plurality of routing devices configured to relay keys and a quantum key distribution device connected with the routing devices and configured to use two or more different paths to perform corresponding quantum key negotiations with another quantum key distribution device to obtain shared keys. The two or more different paths each include one or more of the routing devices.

A system and method for securing communications between a plurality of users communicating over an optical network. The system utilizes a fixed or tunable source optical generator to generate entangled photon pairs, distribute the photons and establish a key exchange between users. The distribution of entangled photon pairs is implemented via at least one wavelength selective switch.

A data communication method includes: processing to-be-transmitted target secret information by using a preset secret sharing algorithm to obtain a plurality of secret fragments; and distributing the plurality of secret fragments to each relay node in a first relay node layer among preset M relay node layers to transmit the plurality of secret fragments to a receiving device by means of each relay node in the M relay node layers, so that the receiving device can obtain the target secret information based on each received secret fragment under the condition that the number of the received secret fragments is greater than or equal to a preset security threshold. By applying the data communication method, in the case that the number of breached relay nodes does not exceed the preset security threshold, an attacker cannot obtain a sufficient number of secret fragments to crack the target secret information.

Methods, apparatus, and systems are provided for performing a quantum key distribution (QKD) protocol between a first device, a second device, and an intermediary device. The intermediary device transmitting: a first secret symbol string over a first quantum channel to the first device; a first basis set over a first communication channel to the first device. The intermediary device; a second secret symbol string over a second quantum channel to the second device; a second basis set over a second communication channel to the second device. The intermediary device generating a third symbol string based on combining the first and second secret symbol strings and transmitting to the second device, via the second communication channel, data representative of the third symbol string. The first device and second device perform a quantum key exchange and sifting based on the corresponding received first and second secret symbol strings and first and second basis sets, and a fourth set of symbols generated by the second device generates a fourth set of symbols based on combining the second received secret symbols with the received third symbol string.