The spin-entangled photon emission device comprises a Fabry-Pérot resonator with a solid state optical waveguide integrated on a substrate. Preferably, the device is used in a configuration that makes it possible to tune the resonance wavelength of the Fabry-Pérot resonator by straining or otherwise adjusting the effective optical length of the waveguide. A diamond membrane is located in the Fabry-Pérot resonator. The diamond membrane comprises a photon-source capable of emitting a photon that is entangled with a spin state of the photon source. A first surface of the diamond membrane abuts to a first minor of the Fabry-Pérot resonator. The optical waveguide has a first end facet bonded to a first surface of the diamond membrane. The first mirror of the Fabry-Pérot resonator is formed by a reflector on the second surface of the diamond membrane. The second mirror of the Fabry-Pérot resonator is formed by a reflector on a second end facet of the optical waveguide or inside the optical waveguide.

Techniques, methods and system, for synchronization of sparse data signals are disclosed, comprising mixing a serial stream of sparse data signals with a serial stream of synchronization signals, to thereby add redundancy to the serial stream of sparse data signals and enable clock regeneration from a serial stream of mixed signals produced by said mixing, emulating the serial stream of synchronization signals by applying the clock regeneration to the serial stream of mixed signals, and generating a stream of parallel synchronization signals having a frequency of the serial stream of synchronization signals, deserializing the serial stream of mixed signals into a stream of parallel mixed signals having a data rate lower than a data rate of the serial signal streams, and demixing the stream of parallel synchronization signals with the stream of parallel mixed signals and thereby removing the redundancy introduced by the mixing into the sparse data signals and generating a parallel stream of demixed signals substantially synchronized with said synchronization signals.

A quantum communication system including an emitter of entangled photons, including a source configured in order to generate at least one pair of entangled photons. The at least one pair of entangled photons including a first photon (P1) emitted on a first propagation path (D1) and simultaneously a second photon (P2) emitted on a second propagation path (D2) different to the first propagation path. A first receiver arranged on the first propagation path (D1), including a complex absorber to absorb the photon in a polarization state selected from among the states of at least two different pairs of complementary polarization states. A second receiver arranged on the second propagation path (D2), including an optical amplifier making it possible to multiply the second photon (P2) while preserving its polarization and a measuring instrument making it possible to measure the average polarization of the multiplied photons.

A quantum communication system including an emitter of entangled photons, including a source configured in order to generate at least one pair of entangled photons. The at least one pair of entangled photons including a first photon (P1) emitted on a first propagation path (D1) and simultaneously a second photon (P2) emitted on a second propagation path (D2) different to the first propagation path. A first receiver arranged on the first propagation path (D1), including a complex absorber to absorb the photon in a polarization state selected from among the states of at least two different pairs of complementary polarization states. A second receiver arranged on the second propagation path (D2), including an optical amplifier making it possible to multiply the second photon (P2) while preserving its polarization and a measuring instrument making it possible to measure the average polarization of the multiplied photons.

A method for routing in a quantum network is provided. The method may include receiving parameters including a fidelity with coherence decay time and an entanglement generation rate for each quantum node in a mesh quantum network by a controller, the controller being configured to communicate with each quantum node of a plurality of quantum nodes in the mesh quantum network. Each quantum node includes a quantum memory and a processor. The method may also include analyzing the fidelity with coherence decay time and the entanglement generation rate to yield a determination of a path fidelity with a path coherence decay time and a path entanglement generation rate between at least one pair of quantum nodes. The method may further include, based on the determination, selecting a quantum communication path from a source node to a destination node.

A method for routing in a quantum network is provided. The method may include receiving parameters including a fidelity with coherence decay time and an entanglement generation rate for each quantum node in a mesh quantum network by a controller, the controller being configured to communicate with each quantum node of a plurality of quantum nodes in the mesh quantum network. Each quantum node includes a quantum memory and a processor. The method may also include analyzing the fidelity with coherence decay time and the entanglement generation rate to yield a determination of a path fidelity with a path coherence decay time and a path entanglement generation rate between at least one pair of quantum nodes. The method may further include, based on the determination, selecting a quantum communication path from a source node to a destination node.

A method for providing an electric waveform at a cryogenic temperatures includes providing an optical signal, which comprises an optical waveform, guiding the optical signal into a cryogenic chamber, and converting the optical waveform of the optical signal into an electric waveform inside the cryogenic chamber.

A method for providing an electric waveform at a cryogenic temperatures includes providing an optical signal, which comprises an optical waveform, guiding the optical signal into a cryogenic chamber, and converting the optical waveform of the optical signal into an electric waveform inside the cryogenic chamber.

A degenerate four-wave mixing (DFWM) squeezed light apparatus includes one or more pump beams, a probe beam, a vapor cell, a repump beam, and a detector. The one or more pump beams includes an input power of no greater than about 150 mW. The vapor cell includes an atomic vapor configured to interact with overlapped pump and probe beams to generate an amplified probe beam and a conjugate beam. The repump beam is configured to optically pump the atomic vapor to a ground state and decrease atomic decoherence of the atomic vapor. The detector is configured to measure squeezing due to quantum correlations between the amplified probe beam and the conjugate beam. The one or more pump beams, the probe beam, and the repump beam are configured to generate two-mode squeezed light by DFWM with squeezing of at least 3 dB below shot noise.

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.