Embodiments of an optical signal copier and an optical parametric amplifier are disclosed herein, which are applied to the communications field. In the embodiments, the optical signal copier is included in the optical parametric amplifier, which generates an invalid signal in a process of transmitting signal light and pump light. The optical signal copier may separate the signal light from the invalid signal and then transmit the signal light to a signal processing module. In this way, the signal processing module may directly process the signal light that does not include the invalid signal, the invalid signal does not occupy transmission bandwidth of the optical parametric amplifier, and the effective transmission bandwidth of the optical parametric amplifier is relatively large.

Embodiments of an optical signal copier and an optical parametric amplifier are disclosed herein, which are applied to the communications field. In the embodiments, the optical signal copier is included in the optical parametric amplifier, which generates an invalid signal in a process of transmitting signal light and pump light. The optical signal copier may separate the signal light from the invalid signal and then transmit the signal light to a signal processing module. In this way, the signal processing module may directly process the signal light that does not include the invalid signal, the invalid signal does not occupy transmission bandwidth of the optical parametric amplifier, and the effective transmission bandwidth of the optical parametric amplifier is relatively large.

According to an example aspect of the present invention, there is provided a travelling wave parametric amplifier comprising a transmission line comprising therein a plurality of Josephson elements and a plurality of shunt capacitors, and wherein at least some of the shunt capacitors are dispersive capacitors comprising an open-ended, distributed transmission line.

Techniques relate to an on-chip Josephson parametric converter. A Josephson ring modulator includes four nodes. A lossless on-chip flux line is capacitively coupled to two adjacent nodes of the four nodes of the Josephson ring modulator. The lossless on-chip flux line has an input port configured to receive a pump drive signal that couples differentially to the two adjacent nodes of the of the Josephson ring modulator. The pump drive signal thereby excites a common mode of the on-chip Josephson parametric converter.

Techniques relate to an on-chip Josephson parametric converter. A Josephson ring modulator includes four nodes. A lossless on-chip flux line is capacitively coupled to two adjacent nodes of the four nodes of the Josephson ring modulator. The lossless on-chip flux line has an input port configured to receive a pump drive signal that couples differentially to the two adjacent nodes of the of the Josephson ring modulator. The pump drive signal thereby excites a common mode of the on-chip Josephson parametric converter.

According to an example aspect of the present invention, there is provided a travelling wave parametric amplifier comprising a waveguide transmission line comprising therein at least ten Josephson elements, wherein each of the at least ten Josephson element comprises a loop, with exactly one Josephson junction of first size on one half of the loop and at least two Josephson junctions of a second size on a second half of the loop, the second size being larger than the first size, a flux bias line configured to generate a magnetic flux threading each of the at least one loop, and a set of resistors coupled with the flux bias line.

According to an example aspect of the present invention, there is provided a travelling wave parametric amplifier comprising a waveguide transmission line comprising therein at least ten Josephson elements, wherein each of the at least ten Josephson element comprises a loop, with exactly one Josephson junction of first size on one half of the loop and at least two Josephson junctions of a second size on a second half of the loop, the second size being larger than the first size, a flux bias line configured to generate a magnetic flux threading each of the at least one loop, and a set of resistors coupled with the flux bias line.

A bandpass parametric amplifier circuit includes a plurality of unit cells. At least one unit cell includes a first inductor having a first node coupled to a center conductor and a second node coupled to ground. There is a first capacitor having a first node coupled to the center conductor and a second node coupled to ground. There is a second inductor having a first node coupled to the center conductor. A second capacitor has a first node coupled to a second node of the second inductor. The second capacitor and the second inductor are in series with the center conductor.

A parametric traveling wave amplifier (200) is disclosed in which the amplifiers include: a co-planar waveguide, in which the co-planar waveguide includes at least one Josephson junction (210) interrupting a center trace (204) of the co-planar waveguide; and at least one shunt capacitor coupled to the co-planar waveguide, in which each shunt capacitor of the at least one shunt capacitor includes a corresponding superconductor trace (214) extending over an upper surface of the center trace of the co-planar waveguide, and in which a gap separates the superconductor trace from the upper surface of the center trace, and in which the co-planar waveguide including the at least one Josephson junction and the shunt capacitor establish a predefined overall impedance for the traveling wave parametric amplifier.

A parametric traveling wave amplifier (200) is disclosed in which the amplifiers include: a co-planar waveguide, in which the co-planar waveguide includes at least one Josephson junction (210) interrupting a center trace (204) of the co-planar waveguide; and at least one shunt capacitor coupled to the co-planar waveguide, in which each shunt capacitor of the at least one shunt capacitor includes a corresponding superconductor trace (214) extending over an upper surface of the center trace of the co-planar waveguide, and in which a gap separates the superconductor trace from the upper surface of the center trace, and in which the co-planar waveguide including the at least one Josephson junction and the shunt capacitor establish a predefined overall impedance for the traveling wave parametric amplifier.