Method and device for determining operating noise temperature of parametric amplifier

Abstract

The present application discloses a method for determining the operating noise temperature of a parametric amplifier, wherein the parametric amplifier is the first element in a quantum amplification chain. The method comprises: respectively presetting first and second relationships between first and second powers of the output signal of the quantum amplification chain corresponding to when the driving signal of the parametric amplifier is in operation and not in operation, and fixed parameters of the first and second elements in the quantum amplification chain; determining a third relationship representing the noise temperature of the parametric amplifier based on the first and second relationships; measuring and obtaining first and second power values of the output signal of the quantum amplification chain when the driving signal of the parametric amplifier is in operation and not in operation; and determining the operating noise temperature of the parametric amplifier based on the first and second power values and the third relationship. The present application proposes a method for measuring the operating noise temperature of a parametric amplifier.

Description

Technical Field

[0001] The present application relates to the quantum field, and in particular to a method and device for determining the operating noise temperature of a parametric amplifier. Background Art

[0002] In the field of quantum computing, quantum computing tasks are performed by quantum processors, which output analog signals carrying the computational results after the computation is completed. Because the analog signals output by quantum processors are very weak, they need to be amplified before being demodulated and analyzed. Typically, a parametric amplifier is connected to a quantum chip to amplify the analog signals output by the quantum chip. Because the analog signals output by quantum processors are very weak and very sensitive to noise, the noise temperature generated by the parametric amplifier during operation directly affects the analog signal to be amplified. Therefore, the operating noise temperature parameters of the parametric amplifier need to be measured to determine whether they meet preset requirements. Because parametric amplifiers are typically set in the same temperature range as quantum processors, such as the 10mK layer of a dilution refrigerator, existing technologies lack a means of measuring the operating noise temperature of parametric amplifiers. Summary of the Invention

[0003] The purpose of this application is to provide a method and device for determining the operating noise temperature of a parametric amplifier, which fills the gap in the existing technology.

[0004] The technical solutions of this application are as follows:

[0005] One aspect of the present application provides a method for determining the operating noise temperature of a parametric amplifier, wherein the parametric amplifier is the first element in a quantum amplification chain; the method comprises:

[0006] Presetting first and second relationships between first and second powers of the output signal corresponding to the quantum amplification link and fixed parameters of the first and second elements in the quantum amplification link when the driving signal of the parametric amplifier is working and not working, respectively;

[0007] determining a third relationship representing a noise temperature of the parametric amplifier based on the first relationship and the second relationship, wherein the third relationship is a function of the first power and the second power;

[0008] Measuring and obtaining a first power value and a second power value of an output signal of the quantum amplification link when a driving signal of the parametric amplifier is in operation and when the driving signal of the parametric amplifier is in operation;

[0009] An operating noise temperature of the parametric amplifier is determined based on the first power value, the second power value, and the third relationship.

[0010] According to the method for determining the operating noise temperature of the parametric amplifier as described above, further, the second element of the quantum amplification chain includes: a first amplifier; wherein the first amplifier is connected to the output end of the parametric amplifier, and the first amplifier is set in a second temperature range, the parametric amplifier is set in a first temperature range, and the temperature of the second temperature range is greater than the temperature of the first temperature range.

[0011] The method for determining the operating noise temperature of the parametric amplifier described above further comprises determining, respectively, a first relationship and a second relationship between the first power and the second power of the output signal of the quantum amplification link and the fixed parameters of the first element and the second element in the quantum amplification link when the driving signal of the parametric amplifier is working and not working:

[0012] P on =(((T0+T P )G P G I G C +T H )G H k B B

[0013] P off =((T0G I G C +T H )G H k B B

[0014] Where: P on is the first power, P off is the second power, T0 is the noise temperature of the signal to be amplified, T P is the noise temperature of the parametric amplifier, T H is the noise temperature of the first amplifier, G P is the gain of the parametric amplifier, G I is the loss parameter of the connection between the parametric amplifier and the first amplifier, G H is the gain of the first amplifier, k B is the Boltzmann constant, and B is the bandwidth of the parametric amplifier.

[0015] The method for determining the operating noise temperature of the parametric amplifier described above further comprises determining a third relationship representing the noise temperature of the parametric amplifier based on the first relationship and the second relationship:

[0016]

[0017]

[0018] In the method for determining the operating noise temperature of a parametric amplifier as described above, further, the second element of the quantum amplification chain also includes: a second amplifier; wherein the second amplifier is connected to the output end of the first amplifier, and the second amplifier is set in a third temperature range, and the temperature of the third temperature range is greater than the temperature of the second temperature range.

[0019] The method for determining the operating noise temperature of the parametric amplifier described above further comprises determining, respectively, a first relationship and a second relationship between the first power and the second power of the output signal of the quantum amplification link and the fixed parameters of the first element and the second element in the quantum amplification link when the driving signal of the parametric amplifier is working and not working:

[0020] P on =(((T0+T P )G P G I G C +T H )G H +T R )G R k B B

[0021] P off =((T0G I G C +T H )G H +T R )G R k B B

[0022] P on is the first power, P off is the second power, T0 is the noise temperature of the signal to be amplified, T P is the noise temperature of the parametric amplifier, T H is the noise temperature of the first amplifier, T R is the noise temperature of the second amplifier, G P is the gain of the parametric amplifier, G I is the loss parameter of the connection between the parametric amplifier and the first amplifier, G H is the gain of the first amplifier, G R is the gain of the second amplifier, k B is the Boltzmann constant, and B is the bandwidth of the parametric amplifier.

[0023] The method for determining the operating noise temperature of the parametric amplifier described above further comprises determining a third relationship representing the noise temperature of the parametric amplifier based on the first relationship and the second relationship:

[0024]

[0025]

[0026] The method for determining the operating noise temperature of a parametric amplifier as described above, further, the connection component between the parametric amplifier and the first amplifier includes a connecting cable; or a connecting cable and a circulator.

[0027] The method for determining the operating noise temperature of the parametric amplifier as described above further includes: optimizing the third relationship to:

[0028]

[0029] The method for determining the operating noise temperature of the parametric amplifier as described above, further comprising: measuring and obtaining the first power value and the second power value of the quantum amplification link output signal when the driving signal of the parametric amplifier is working and not working, comprising: measuring and obtaining multiple first power values and multiple second power values of the quantum amplification link output signal when the driving signal of the parametric amplifier is working and not working multiple times.

[0030] The method for determining the operating noise temperature of the parametric amplifier as described above, further comprising: determining the operating noise temperature of the parametric amplifier based on the first power value, the second power value, and the third relationship, including:

[0031] obtaining a plurality of Y values based on a plurality of the first power values and a plurality of the second power values;

[0032] determining an operating noise temperature of a plurality of the parametric amplifiers based on the third relationship and a plurality of the Y values;

[0033] An average value of the operating noise temperatures of the plurality of parametric amplifiers is determined as the operating noise temperature of the parametric amplifier.

[0034] On the other hand, the present application provides an apparatus for determining the operating noise temperature of a parametric amplifier, wherein the parametric amplifier is an element in a quantum amplification chain. The apparatus comprises: a first model establishment module for respectively presetting first and second relationships between first and second powers of an output signal corresponding to the quantum amplification chain and fixed parameters of elements present in the quantum amplification chain when a driving signal of the parametric amplifier is in operation and inoperative; a second model establishment module for determining, based on the first and second relationships, a third relationship representing the noise temperature of the parametric amplifier, wherein the third relationship is a function of the first and second powers; a measurement module for measuring and obtaining first and second power values of the output signal of the quantum amplification chain when the driving signal of the parametric amplifier is in operation and inoperative; and a determination module for determining the operating noise temperature of the parametric amplifier based on the first and second power values and the third relationship.

[0035] Compared with the prior art, the present application first constructs a quantum amplification link based on a parametric amplifier to amplify the quantum processor, obtains a first relationship and a second relationship between the output signal of the quantum amplification link and the fixed parameters of all components in the quantum amplification link, and then obtains a third relationship between the noise temperature characterizing the quantum amplification link and the fixed parameters of the second component in the quantum amplification link; then, the quantum amplification link is connected to the quantum processor to perform measurement, and a first power value and a second power value of the output signal of the quantum amplification link are obtained to characterize the measurement parameters of the second component in the quantum amplification link. Combined with the third relationship, the operating noise temperature of the parametric amplifier can be obtained, filling the gap in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of a method for determining the operating noise temperature of a parametric amplifier provided in an embodiment of the present application;

[0037] Figure 2 A flow chart of obtaining the operating noise temperature of a parametric amplifier based on multiple measurements provided in an embodiment of the present application;

[0038] Figure 3 An embodiment of the present application provides a device for determining the operating noise temperature of a parametric amplifier.

[0039] Description of reference numerals: 10 - first model building module, 20 - second model building module, 30 - second model building module, 40 - determination module. DETAILED DESCRIPTION

[0040] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application.

[0041] like Figure 1 As shown, an embodiment of the present application provides a method for determining the operating noise temperature of a parametric amplifier, wherein the parametric amplifier is the first element in a quantum amplification chain; the method comprises the following steps:

[0042] S1: respectively presetting first and second relationships between first and second powers of the output signal corresponding to the quantum amplification link and fixed parameters of the first and second elements in the quantum amplification link when the driving signal of the parametric amplifier is working and not working.

[0043] The analog signal output by a quantum processor, carrying quantum state information, is very weak. Furthermore, the operating environment of a quantum processor is relatively low, typically located in the ultra-low temperature layer of a dilution refrigerator, such as 10mK (approximately -273 degrees Celsius). The functional modules that demodulate and process the analog signal output by the quantum processor are typically located at room temperature. Therefore, a quantum amplification chain is typically installed at the back end of the quantum processor. The parametric amplifier is the first element in the chain, performing the initial amplification of the analog signal output by the quantum processor. Furthermore, a second element in the chain, connected to the parametric amplifier, processes the amplified signal output by the parametric amplifier.

[0044] The parametric amplifier requires a driving signal when operating, and the signal output by the quantum amplification link is a signal amplified by the parametric amplifier. When the driving signal is not provided, the parametric amplifier is inoperative, and the signal output by the quantum amplification link is a signal that has not been amplified by the parametric amplifier, but is only a signal processed by the second element. Therefore, for the constructed quantum amplification link, the first and second powers of the quantum amplification link output signal are obtained by respectively presetting the parametric amplifier to operate and not operate. The first and second powers obtained in this case are related to the fixed parameters of the first and second elements in the quantum amplification link. It is understandable that different values of the fixed parameters of the first and second elements will also result in different first and second powers. That is, the first and second relationships between the first and second powers and the fixed parameters of the first and second elements are obtained. In addition, the fixed parameters include but are not limited to noise temperature, gain, loss, bandwidth, etc.

[0045] S2: Determine a third relationship representing the noise temperature of the parametric amplifier based on the first relationship and the second relationship, wherein the third relationship is a function of the first power and the power.

[0046] The first and second relationships are the relative relationships between the power of the quantum amplification link output signal and the fixed parameters of the first and second components. The first component is a parametric amplifier. Therefore, the first and second relationships are converted to obtain a third relationship between the noise temperature of the parametric amplifier and the fixed parameters of the second component in the quantum amplification link. Since the fixed parameters of each component in the quantum amplification link correspond to the first and second powers, the third relationship can also be expressed as a function of the first and second powers.

[0047] S3: Measure and obtain a first power value and a second power value of the output signal of the quantum amplification link when the driving signal of the parametric amplifier is working and when the driving signal of the parametric amplifier is not working.

[0048] Specifically, the third relationship characterizing the noise temperature of the parametric amplifier obtained in step S20 is obtained based on the constructed quantum amplification link. By connecting the quantum amplification link to the quantum processor and performing specific measurement steps, first and second power values of the quantum amplification link output signal are obtained when the parametric amplifier's drive signal is operating and when it is not operating. It will be understood that the obtained first and second power values are measured values obtained after the analog signal output by the quantum processor is processed by all components in the quantum amplification link.

[0049] S4: Determining an operating noise temperature of the parametric amplifier based on the first power value, the second power value, and the third relationship. Specifically, the third relationship represents a relative relationship between the noise temperature of the parametric amplifier and a fixed parameter of a second element in the quantum amplification chain. After obtaining the first power value and the second power value through specific measurement, the operating noise temperature of the parametric amplifier can be determined by combining the first power value, the second power value, and the third relationship.

[0050] First, a quantum amplification link is constructed based on a parametric amplifier to amplify the quantum processor, and a first relationship and a second relationship between the output signal of the quantum amplification link and the fixed parameters of all components in the quantum amplification link are obtained. Then, a third relationship characterizing the noise temperature of the quantum amplification link and the fixed parameter of the second component in the quantum amplification link is obtained; then, the quantum processor is connected to the quantum amplification link to perform measurement, and a first power value and a second power value of the output signal of the quantum amplification link are obtained. Combined with the third relationship, the operating noise temperature of the parametric amplifier can be obtained.

[0051] It is understandable that the parametric amplifier is located in the extremely low temperature environment where the quantum processor operates, and its working performance cannot be directly tested. By building a quantum amplification chain including the parametric amplifier and the second element and performing specific tests, the operating noise temperature of the parametric amplifier is measured based on the test results and the second element.

[0052] As an implementation method of an embodiment of the present application, the second element of the quantum amplification link includes: a first amplifier; the first amplifier is connected to the output end of the parametric amplifier, and the first amplifier is set in a second temperature range, the parametric amplifier is set in a first temperature range, and the temperature of the second temperature is greater than the temperature of the first temperature range. Specifically, the second element is the first amplifier located in the second temperature range, which is connected to the parametric amplifier located in the first temperature range through a connector. Since the temperature of the second temperature is greater than the temperature of the first temperature range, the magnitude of the noise temperature of the first amplifier is much greater than the magnitude of the noise temperature of the parametric amplifier. When testing the quantum amplification link, it can be understood that the operating noise temperature of the second amplifier has a very small effect on the parametric amplifier, which can be almost ignored, and the second amplifier is used to measure the operating noise temperature of the parametric amplifier.

[0053] As an implementation manner of an embodiment of the present application, a first relationship and a second relationship between a first power and a second power of an output signal of the quantum amplification link and fixed parameters of the first element and the second element in the quantum amplification link when the driving signal of the parametric amplifier is working and not working are respectively determined:

[0054] P on =(((T0+T P )G P G I G C +T H )G H k B B

[0055] P off =((T0G I G C +T H )G H k B B

[0056] Where: P on is the first power, P off is the second power, T0 is the noise temperature of the signal to be amplified, T P is the noise temperature of the parametric amplifier, T H is the noise temperature of the first amplifier, G P is the gain of the parametric amplifier, G I is the loss parameter of the connection between the parametric amplifier and the first amplifier, G H is the gain of the first amplifier, k Bis the Boltzmann constant, and B is the bandwidth of the parametric amplifier. For the constructed quantum amplification link, the relationship between the signal power output by the entire quantum amplification link and the fixed parameters can be obtained based on the fixed parameters of each component in the quantum amplification link.

[0057] As an implementation manner of the embodiment of the present application, a third relationship representing the noise temperature of the parametric amplifier is determined based on the first relationship and the second relationship:

[0058]

[0059]

[0060] Among them, Y can be understood as the Y factor, which can be used to characterize the amplification factor. For the constructed quantum amplification link, the Y factor is the ratio of the first power to the second power. Combining the first relationship and the second relationship, the noise temperature T of the parametric amplifier can be obtained. P From the above formula, it can be found that the noise temperature of the parametric amplifier is related to the fixed parameters of each component of the quantum amplification link and Y.

[0061] As an implementation method of an embodiment of the present application, it is characterized in that the second element of the quantum amplification link also includes: a second amplifier, the second amplifier is connected to the output end of the first amplifier, and the second amplifier is set in a third temperature range, and the temperature of the third temperature range is greater than the temperature of the second temperature range. Specifically, at the back end of the first amplifier, a second amplifier is set in the third temperature range to amplify the amplified signal output by the first amplifier again. The third temperature range is usually a room temperature environment, and the signal output by the second amplifier is measured by a test device, and the test device includes but is not limited to a spectrum analyzer, an oscilloscope, etc. The first power value and the second power value can be directly obtained by the test device.

[0062] After a second amplifier is provided in the quantum amplification link, a first relationship and a second relationship between a first power and a second power of an output signal of the quantum amplification link and a noise temperature, a gain, and a loss of an element in the quantum amplification link when a driving signal of the parametric amplifier is working and not working are respectively determined:

[0063] P on =(((T0+T P )G P G I G C +T H )G H +T R )G R k B B

[0064] P off =((T0G I G C +T H )G H +T R )G R k B B

[0065] P on is the first power, P off is the second power, T0 is the noise temperature of the signal to be amplified, T P is the noise temperature of the parametric amplifier, T H is the noise temperature of the first amplifier, T R is the noise temperature of the second amplifier, G P is the gain of the parametric amplifier, G I is the loss parameter of the cable between the parametric amplifier and the first amplifier, G H is the gain of the first amplifier, G R is the gain of the second amplifier, k B is the Boltzmann constant, and B is the bandwidth of the parametric amplifier.

[0066] After setting a second amplifier in the quantum amplification link and redetermining the first and second relationships between the first and second powers of the output signal of the quantum amplification link and the noise temperature, gain, and loss of the element in the quantum amplification link when the driving signal of the parametric amplifier is working and not working, the corresponding third relationship also needs to be redetermined. That is, based on the first and second relationships, the third relationship representing the noise temperature of the parametric amplifier is determined as:

[0067]

[0068]

[0069] As an implementation method of an embodiment of the present application, the connector between the parametric amplifier and the first amplifier includes a connecting cable; or a connecting cable and a circulator. Since the parametric amplifier is located in the first temperature range and the first amplifier is located in the second temperature range, a connecting cable is used to electrically connect the parametric amplifier and the first amplifier to realize signal transmission. In addition, a circulator can also be provided, and the quantum processor is connected through the first end of the circulator to receive the analog signal to be amplified, and output it to the parametric amplifier through the second port of the circulator. The parametric amplifier transmits the amplified analog signal back to the second port of the circulator after reflection, and outputs it to the first amplifier through the third port of the circulator. By providing a circulator, it is possible to prevent the signal from being reflected due to impedance mismatch during transmission.

[0070] As an implementation method of the embodiment of the present application, the method further includes: optimizing the third relationship to:

[0071]

[0072] The third relationship, representing the noise temperature of the parametric amplifier, obtained from the first and second relationships, includes the fixed parameters of all components in the quantum amplification chain, such as the fixed parameters of the first amplifier, the second amplifier, the connecting cable, and the circulator. These parameters are numerous. The fixed parameters of the second amplifier and the circulator have a very weak impact on the noise temperature of the parametric amplifier and can be ignored in the calculation. The third relationship is represented solely by the gain of the parametric amplifier, the noise temperature of the first amplifier, the loss of the connecting cable connecting the parametric amplifier and the first amplifier, and the Y factor, facilitating calculation.

[0073] As one implementation of an embodiment of the present application, measuring and obtaining first and second power values of the quantum amplification link output signal when the parametric amplifier's drive signal is active and inactive includes: repeatedly measuring and obtaining multiple first and second power values of the quantum amplification link output signal when the parametric amplifier's drive signal is active and inactive. By repeatedly measuring and obtaining multiple first and second power values and obtaining the corresponding operating noise temperature of the parametric amplifier, measurement accuracy can be improved.

[0074] The present application constructs a multi-stage quantum amplification link covering different temperature ranges for measuring a quantum processor. The quantum amplification link includes a parametric amplifier connected to the quantum processor in a first temperature range, a first amplifier connected to the parametric amplifier in a second temperature range, and a second amplifier connected to the first amplifier in a third temperature range. For the constructed quantum amplification link, a first relationship and a second relationship between the output signal power of the amplification link and the fixed parameters of each component in the quantum amplification link are determined when the parametric amplifier is turned on and off, respectively. Then, the corresponding relationship between the noise temperature of the parametric amplifier and the noise temperature of the first amplifier is determined in combination with the Y factor. The output signal power of the quantum amplification link is measured by a measuring device to obtain a first power value and a second power value of the output signal when the parametric amplifier is turned on and off, respectively. The actual measured Y factor is obtained based on the ratio of the first power value and the second power value. Moreover, since the magnitude of the noise temperature of the parametric amplifier is much smaller than the magnitude of the noise temperature of the first amplifier, the theoretical noise temperature of the first amplifier is defaulted to the noise temperature during operation. Then, the operating noise temperature of the parametric amplifier can be obtained by combining the measured Y factor and the third relationship.

[0075] As an implementation manner of the embodiment of the present application, determining the operating noise temperature of the parametric amplifier based on the first power value, the second power value, and the third relationship includes the following steps:

[0076] S41: Obtain multiple Y values based on multiple first power values and multiple second power values.

[0077] S42: Determine the operating noise temperatures of the plurality of parametric amplifiers based on the third relationship and the plurality of Y values.

[0078] S43: Determine the average value of the operating noise temperatures of the plurality of parametric amplifiers as the operating noise temperature of the parametric amplifier.

[0079] Perform multiple measurements, and the first power value and the second power value obtained in each measurement can be combined with a Y factor. Combined with the formula of the third relationship, the operating noise temperatures of multiple parametric amplifiers can be obtained, and the average of the multiple operating noise temperatures is calculated. The average value is used as the operating noise temperature of the parametric amplifier to ensure the accuracy of the measurement.

[0080] Based on the same application concept, an embodiment of the present application provides a device for determining the operating noise temperature of a parametric amplifier, wherein the parametric amplifier is an element in a quantum amplification chain; the device includes: a first model establishment module 10, for respectively presetting first and second relationships between first and second powers of the output signal corresponding to the quantum amplification chain when the driving signal of the parametric amplifier is working and not working and fixed parameters of the elements present in the quantum amplification chain; a second model establishment module 20, for determining a third relationship representing the noise temperature of the parametric amplifier based on the first and second relationships, wherein the third relationship is a function of the first and second powers; a measurement module 30, for measuring and obtaining first and second power values of the output signal of the quantum amplification chain when the driving signal of the parametric amplifier is working and not working; and a determination module 40, for determining the operating noise temperature of the parametric amplifier based on the first power value, the second power value, and the third relationship.

[0081] The above describes in detail the structure, features and effects of the present application based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present application, but the present application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of the present application, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present application.

Claims

1. A method for determining the operating noise temperature of a parametric amplifier, characterized in that: The parametric amplifier is the first element in a quantum amplification chain; the method comprises: Presetting first and second relationships between first and second powers of the output signal corresponding to the quantum amplification link and fixed parameters of the first and second elements in the quantum amplification link when the driving signal of the parametric amplifier is in operation and inoperative, respectively; wherein the second element includes a first amplifier, the first amplifier is connected to the output end of the parametric amplifier, and the first amplifier is set in a second temperature range, the parametric amplifier is set in a first temperature range, and the temperature in the second temperature range is greater than the temperature in the first temperature range; determining a third relationship representing a noise temperature of the parametric amplifier based on the first relationship and the second relationship, wherein the third relationship is a function of the first power and the second power; Measuring and obtaining a first power value and a second power value of an output signal of the quantum amplification link when a driving signal of the parametric amplifier is in operation and when the driving signal of the parametric amplifier is in operation; An operating noise temperature of the parametric amplifier is determined based on the first power value, the second power value, and the third relationship.

2. The method for determining the operating noise temperature of a parametric amplifier according to claim 1, wherein: Determine respectively a first relationship and a second relationship between a first power and a second power of an output signal of the quantum amplification link and fixed parameters of the first element and the second element in the quantum amplification link when the driving signal of the parametric amplifier is working and not working: P on =((T0+T P )G P G I G C +T H )G H k B B P off =(T0G I G C +T H )G H k B B Where: P on is the first power, P off is the second power, T0 is the noise temperature of the signal to be amplified, T P is the noise temperature of the parametric amplifier, T H is the noise temperature of the first amplifier, G P is the gain of the parametric amplifier, G I is the loss parameter of the cable in the connection between the parametric amplifier and the first amplifier, G H is the gain of the first amplifier, k B is the Boltzmann constant, and B is the bandwidth of the parametric amplifier.

3. The method for determining the operating noise temperature of a parametric amplifier according to claim 2, wherein: A third relationship representing the noise temperature of the parametric amplifier is determined based on the first relationship and the second relationship:

4. The method for determining the operating noise temperature of a parametric amplifier according to claim 1, wherein: The second element of the quantum amplification link further includes: a second amplifier; The second amplifier is connected to the output end of the first amplifier, and the second amplifier is set in a third temperature range, and the temperature of the third temperature range is greater than the temperature of the second temperature range.

5. The method for determining the operating noise temperature of a parametric amplifier according to claim 4, wherein: Determine respectively a first relationship and a second relationship between a first power and a second power of an output signal of the quantum amplification link and fixed parameters of the first element and the second element in the quantum amplification link when the driving signal of the parametric amplifier is working and not working: P on =(((T0+T P )G P G I G C +T H )G H +T R )G R k B B P off =((T o G I G C +T H )G H +T R )G R k B B P on is the first power, P off is the second power, T0 is the noise temperature of the signal to be amplified, T P is the noise temperature of the parametric amplifier, T H is the noise temperature of the first amplifier, T R is the noise temperature of the second amplifier, G P is the gain of the parametric amplifier, G I is the loss parameter of the cable in the connection between the parametric amplifier and the first amplifier, G H is the gain of the first amplifier, G R is the gain of the second amplifier, k B is the Boltzmann constant, and B is the bandwidth of the parametric amplifier.

6. The method for determining the operating noise temperature of a parametric amplifier according to claim 5, wherein: A third relationship representing the noise temperature of the parametric amplifier is determined based on the first relationship and the second relationship:

7. The method for determining the operating noise temperature of a parametric amplifier according to any one of claims 3 or 6, characterized in that: The method further includes optimizing the third relationship to:

8. The method for determining the operating noise temperature of a parametric amplifier according to any one of claims 3 or 6, wherein: The measuring and obtaining of a first power value and a second power value of an output signal of the quantum amplification link when the driving signal of the parametric amplifier is working and when the driving signal of the parametric amplifier is not working includes: Multiple measurements are performed to obtain multiple first power values and multiple second power values of the quantum amplification link output signal when the driving signal of the parametric amplifier is working and when the driving signal of the parametric amplifier is not working.

9. The method for determining the operating noise temperature of a parametric amplifier according to claim 8, wherein: Determining the operating noise temperature of the parametric amplifier based on the first power value, the second power value, and the third relationship includes: obtaining a plurality of Y values based on a plurality of the first power values and a plurality of the second power values; determining an operating noise temperature of a plurality of the parametric amplifiers based on the third relationship and a plurality of the Y values; An average value of the operating noise temperatures of the plurality of parametric amplifiers is determined as the operating noise temperature of the parametric amplifier.

10. A device for determining the operating noise temperature of a parametric amplifier, characterized in that: The parametric amplifier is the first element in the quantum amplification chain; the device includes: A first model building module is configured to preset first and second relationships between first and second powers of an output signal corresponding to the quantum amplification link and fixed parameters of a first element and a second element in the quantum amplification link when a driving signal of the parametric amplifier is in operation and inoperative, respectively; wherein the second element includes a first amplifier, the first amplifier is connected to an output end of the parametric amplifier, and the first amplifier is set in a second temperature range, the parametric amplifier is set in a first temperature range, and the temperature in the second temperature range is greater than the temperature in the first temperature range; a second model building module, configured to determine a third relationship representing the noise temperature of the parametric amplifier based on the first relationship and the second relationship, wherein the third relationship is a function of the first power and the second power; A measurement module, measuring and obtaining a first power value and a second power value of an output signal of the quantum amplification link when a driving signal of the parametric amplifier is in operation and when the driving signal of the parametric amplifier is in operation; A determination module is configured to determine an operating noise temperature of the parametric amplifier based on the first power value, the second power value, and the third relationship.

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