Abstract: Conventional readout of a superconducting nanowire single-photon detector (SNSPD) sets an upper bound on the output voltage to be the product of the bias current and the load impedance, IB×Zload, where Zload is limited to 50? in standard RF electronics. This limit is broken/exceeded by interfacing the 50? load and the SNSPD using an integrated superconducting transmission line taper. The taper is a transformer that effectively loads the SNSPD with high impedance without latching. The taper increases the amplitude of the detector output while preserving the fast rising edge. Using a taper with a starting width of 500 nm, a 3.6× higher pulse amplitude, 3.7× faster slew rate, and 25.1 ps smaller timing jitter was observed. The taper also makes the detector's output voltage sensitive to the number of photon-induced hotspots and enables photon number resolution.

Abstract: Methods, systems, and devices for testing an electro-optic device such as a modulator or a switch are disclosed.

Abstract: The invention relates to a Quantum Key Distribution system comprising a transmitter 300 and a receiver 400 for exchanging a quantum key via a quantum channel 600 through a decoy-state three state protocol wherein the transmitter comprises a transmitter processing unit 340 adapted to use random numbers from a quantum random generator to select a quantum state to encode from different states of intensity and basis, a Pulsed light source 310 adapted to generate an optical pulse, a time-bin interferometer 320 through which the generated optical pulse passes and which transforms generated optical pulse into two coherent pulses separated by the time bin duration, a single intensity modulator 360 adapted to change the intensity of the two pulses individually according to the choice made by the transmitter processing unit 340, and a variable optical attenuator 370 adapted to reduce the overall signal intensity to the optimum photon number per pulse.

Abstract: Conventional readout of a superconducting nanowire single-photon detector (SNSPD) sets an upper bound on the output voltage to be the product of the bias current and the load impedance, IB×Zload, where Zload is limited to 50? in standard RF electronics. This limit is broken/exceeded by interfacing the 50? load and the SNSPD using an integrated superconducting transmission line taper. The taper is a transformer that effectively loads the SNSPD with high impedance without latching. The taper increases the amplitude of the detector output while preserving the fast rising edge. Using a taper with a starting width of 500 nm, a 3.6× higher pulse amplitude, 3.7× faster slew rate, and 25.1 ps smaller timing jitter was observed. The taper also makes the detector's output voltage sensitive to the number of photon-induced hotspots and enables photon number resolution.

Abstract: The invention relates to a Quantum Key Distribution system comprising a transmitter 300 and a receiver 400 for exchanging a quantum key via a quantum channel 600 through a decoy-state three state protocol wherein the transmitter comprises a transmitter processing unit 340 adapted to use random numbers from a quantum random generator to select a quantum state to encode from different states of intensity and basis, a Pulsed light source 310 adapted to generate an optical pulse, a time-bin interferometer 320 through which the generated optical pulse passes and which transforms generated optical pulse into two coherent pulses separated by the time bin duration, a single intensity modulator 360 adapted to change the intensity of the two pulses individually according to the choice made by the transmitter processing unit 340, and a variable optical attenuator 370 adapted to reduce the overall signal intensity to the optimum photon number per pulse.

Abstract: Cryogenic device comprising at least two chambers at two different temperatures, a first chamber at a first temperature T1 accommodating a sample, and a second chamber at a second temperature T2 greater than T1 and being adapted to accommodate a cooling device, said cooling device being adapted to cool wirelines connecting said sample to an external element detector, wherein said cooling device is an IMS thermalization plate comprising at least one wire-guide having an input for plugging a wire line connected to the sample and an output for plugging a wire line connected to said external element, said wire-guide being thermally connected to the first chamber.

Abstract: Cryogenic device comprising at least two chambers at two different temperatures, a first chamber at a first temperature T1 accommodating a sample, and a second chamber at a second temperature T2 greater than T1 and being adapted to accommodate a cooling device, said cooling device being adapted to cool wirelines connecting said sample to an external element detector, wherein said cooling device is an IMS thermalization plate comprising at least one wire-guide having an input for plugging a wire line connected to the sample and an output for plugging a wire line connected to said external element, said wire-guide being thermally connected to the first chamber.