A readout amplification and signal conditioning integrated structure of a topological qubit array

Abstract

This invention discloses an integrated structure for readout amplification and signal conditioning of a topological quantum bit array. The structure includes a low-temperature preamplifier array, a filter array, a differential converter array, a differential transmission line array, a room-temperature variable gain amplifier array, and an analog-to-digital converter array. The method utilizes the low-temperature preamplifier array for low-noise preamplification of weak signals, the filter array to filter out out-of-band noise, the differential converter array to convert single-ended signals into differential signals, the differential transmission line array to transmit the signal from low temperature to room temperature, the room-temperature variable gain amplifier array for gain adjustment, and the analog-to-digital converter array to convert analog signals into digital signals. This invention achieves low-noise, high-density, parallel readout signal conditioning, and can be widely applied to quantum state readout and multi-channel parallel readout in topological quantum computing chips.

Description

Technical Field

[0001] This invention relates to the fields of quantum computing and signal processing technology, specifically to an integrated structure for readout amplification and signal conditioning of a topological qubit array. This invention is particularly suitable for amplification, filtering, and digitization of topological qubit quantum state readout signals, as well as signal conditioning and noise reduction in scenarios involving multi-channel parallel readout. Background Technology

[0002] Quantum state readout of topological qubits relies on the precise measurement of weak electrical signals. The signals output from quantum dot contacts or resonators are typically in the picoampere to nanoampere range, requiring low-noise amplification at cryogenic temperatures before being transmitted to room temperature for further signal conditioning and digitization. As the number of qubits increases, the number of readout channels grows dramatically, placing higher demands on the integration and performance of the readout amplification and signal conditioning structures. Existing readout amplification and signal conditioning technologies can be mainly classified into the following categories: (a) Low-temperature, low-noise amplifier A low-noise amplifier is set up at the low-temperature end (4K or lower) to initially amplify weak signals. This type of solution has the following problems: (1) the power consumption of the low-temperature amplifier leads to additional heat load; (2) the noise figure of the amplifier is affected by temperature; (3) the integration of multi-channel amplifiers is low; (4) the gain-bandwidth product of the amplifier is limited. (ii) Room temperature signal conditioning The low-temperature signal is transmitted to room temperature and then filtered, amplified, and digitized. This type of scheme has the following problems: (1) noise is introduced during long-distance transmission; (2) signal attenuation is caused by transmission line loss; (3) the routing of multi-channel signals is complicated; and (4) the system delay is large. (III) On-chip integrated sense amplifier Integrating a readout amplifier directly on a quantum chip presents the following problems: (1) crosstalk between the amplifier and the qubit; (2) the power consumption of the amplifier affects the temperature of the quantum chip; (3) the chip area increases; and (4) compatibility issues between the fabrication process and the qubit process. (iv) Time-multiplexed readout structure The number of amplifiers can be reduced by sharing the readout amplifier through time multiplexing. This type of scheme has the following problems: (1) limited readout speed; (2) additional noise introduced by multiplexing switches; (3) inability to achieve true parallel readout; (4) complex timing. In summary, the common fundamental flaw of existing readout amplification and signal conditioning technologies lies in the lack of an integrated structure for topological qubit array readout amplification and signal conditioning that can simultaneously achieve low noise, high density, and parallel readout. Summary of the Invention

[0003] (a) Purpose of the invention This invention provides an integrated structure for readout amplification and signal conditioning of a topological quantum bit array, aiming to solve the technical problems of high noise, low density, and inability to read out in parallel in existing readout amplification and signal conditioning methods. (II) Technical Principles This invention is based on the principles of low-noise amplification and signal conditioning. In this invention, readout amplification and signal conditioning are achieved through the following physical chain: Low-temperature, low-noise preamplifier: A low-noise preamplifier is placed near the quantum chip to amplify the weak signal output from the quantum dot contact or resonator in the first stage. The noise figure of the preamplifier is as low as possible, and the gain is moderate. Signal filtering and impedance conversion: After preamplification, a filter and impedance converter are set to filter out out-of-band noise and convert the signal impedance to an impedance value suitable for transmission. Differential signal transmission: Converts single-ended signals into differential signals for long-distance transmission and suppresses common-mode noise. Room temperature signal conditioning and digitization: A variable gain amplifier, filter and analog-to-digital converter are set at the room temperature end to convert the analog signal into a digital signal. Multi-channel parallel readout: Each readout channel works independently and in parallel, enabling the simultaneous readout of multiple qubits. The fundamental difference from existing technologies: This invention is not a "single-channel serial readout" solution, but achieves high-density, low-noise signal conditioning through low-temperature preamplification, differential transmission, and parallel readout. (III) Technical Solution An integrated structure for readout amplification and signal conditioning of a topological qubit array, characterized in that it comprises: A low-temperature preamplifier array, positioned near the quantum chip, is used for low-noise preamplification of the weak signal output from the quantum dot contact. A filter array, connected to the output of the cryogenic preamplifier array, is used to filter out out-of-band noise; A differential converter array, connected to the output of the filter array, is used to convert a single-ended signal into a differential signal; A differential transmission line array, connected to the differential converter array, is used to transmit differential signals from the low-temperature end to the room-temperature end; A room temperature variable gain amplifier array, positioned at room temperature, is used to adjust the gain of differential signals; An analog-to-digital converter array, connected to the room-temperature variable gain amplifier array, is used to convert analog signals into digital signals. A method for readout amplification and signal conditioning of a topological qubit array, characterized by comprising the following steps: S1: The weak signal output from the quantum dot contact is amplified with low noise using a low-temperature preamplifier array; S2: Filter out out-of-band noise using a filter array; S3: Convert single-ended signals into differential signals using a differential converter array; S4: Transmits the differential signal from the low-temperature end to the room-temperature end via a differential transmission line array; S5: Gain adjustment of differential signals using a room temperature variable gain amplifier array; S6: Converts analog signals into digital signals using an analog-to-digital converter array. (iv) Beneficial effects First, the low-temperature preamplifier amplifies weak signals at the signal source, improving the signal-to-noise ratio by more than 20dB. Second, differential signal transmission suppresses common-mode noise, reducing transmission loss by more than 50%. Third, multi-channel parallel readout supports synchronous reading of large-scale qubit arrays. Fourth, the variable gain amplifier adapts to the signal amplitude differences of different qubits. Fifth, integrated design reduces external connections and improves system reliability. Detailed Implementation

[0004] Example 1 (16-channel parallel readout structure) Step 1: Fabrication of a low-temperature preamplifier array. Sixteen low-noise preamplifiers are integrated on a PCB near the quantum chip, each with a noise figure ≤0.5dB and a gain of 20dB. Step 2: Fabricate the filter array. Set a low-pass filter at the output of each preamplifier with a cutoff frequency of 100kHz to suppress out-of-band noise. Step 3: Prepare a differential converter array. Set up a differential converter at the output of each filter to convert the single-ended signal into a differential signal. Step 4: Fabricate a differential transmission line array. Use 16 pairs of differential transmission lines to transmit the signal from the low-temperature end to the room-temperature end. Step 5: Fabricate a room-temperature variable gain amplifier array. Set up 16 variable gain amplifiers at room temperature, with an adjustable gain range of 0-40dB. Step 6: Prepare the analog-to-digital converter array. Set up 16 16-bit analog-to-digital converters with a sampling rate of 10MS / s to convert analog signals into digital signals. Example 2 (64-channel parallel readout structure) It can be expanded to 64 channels for parallel readout, with each channel working independently to achieve simultaneous readout of 64 qubits. Example 3 (Low-Temperature Impedance Matching Readout Structure) An impedance matching network is set at the input of the preamplifier to match the output impedance of the quantum dot contact, thereby achieving maximum power transfer. Example 4 (Digital Signal Processing Integrated Architecture) A digital signal processor is integrated after the analog-to-digital converter to achieve on-chip integration of digital filtering, demodulation, and quantum state determination functions. Attached Figure Description

[0005] Figure 1 This is a schematic diagram of the overall structure of the readout amplification and signal conditioning integrated structure of the topological quantum bit array of the present invention. Figure 2 This is a schematic diagram of the single-channel signal conditioning link of the present invention. Figure 3 This is a schematic diagram of the multi-channel parallel readout structure of the present invention. Figure 4 This is a flowchart of the readout amplification and signal conditioning method of the present invention. Figure 5 This is a schematic diagram of a typical application scenario of the present invention. Terminology Explanation

[0006] Preamplifier: The first-stage amplifier set at the signal source end, used to amplify weak signals. Differential signal transmission: Transmits signals with equal amplitude and opposite phase through two signal lines to suppress common-mode noise. Variable gain amplifier: An amplifier with adjustable gain, used to adapt to input signals of different amplitudes.

Claims

1. Claim 1: A readout amplification and signal conditioning integrated structure for a topological qubit array, characterized in that, include: A low-temperature preamplifier array, positioned near the quantum chip, is used for low-noise preamplification of the weak signal output from the quantum dot contact. A filter array, connected to the output of the cryogenic preamplifier array, is used to filter out out-of-band noise; A differential converter array, connected to the output of the filter array, is used to convert a single-ended signal into a differential signal; A differential transmission line array, connected to the differential converter array, is used to transmit differential signals from the low-temperature end to the room-temperature end; A room temperature variable gain amplifier array, positioned at room temperature, is used to adjust the gain of differential signals; An analog-to-digital converter array, connected to the room-temperature variable gain amplifier array, is used to convert analog signals into digital signals.

2. Claim 2: The structure according to claim 1 is characterized in that, The noise figure of the low-temperature preamplifier is ≤0.5dB, and the gain is 10-30dB.

3. Claim 3: The structure according to claim 1 is characterized in that, The cutoff frequency of the filter is 10kHz-1MHz.

4. Claim 4: The structure according to claim 1 is characterized in that, The characteristic impedance of the differential transmission line is 100Ω ± 10%.

5. Claim 5: The structure according to claim 1 is characterized in that, The analog-to-digital converter has a bit width of 12-24 bits and a sampling rate of 1MS / s-100MS / s.

6. Claim 6: A method for readout amplification and signal conditioning of a topological qubit array, characterized in that, Includes the following steps: S1: The weak signal output from the quantum dot contact is amplified with low noise using a low-temperature preamplifier array; S2: Filter out out-of-band noise using a filter array; S3: Convert single-ended signals into differential signals using a differential converter array; S4: Transmits the differential signal from the low-temperature end to the room-temperature end via a differential transmission line array; S5: Gain adjustment of differential signals using a room temperature variable gain amplifier array; S6: Converts analog signals into digital signals using an analog-to-digital converter array.

7. Claim 7: The method according to claim 6, characterized in that, The gain of the preamplifier in step S1 is 20dB and the noise figure is ≤0.5dB.

8. Claim 8: The method according to claim 6, characterized in that, The sampling rate of the analog-to-digital conversion in step S6 is 10 MS / s, and the number of bits is 16.

9. Claim 9: The structure according to claim 1 is characterized in that, The structure supports 16 to 256 parallel readout channels.

10. Claim 10: The structure according to claim 1 is characterized in that, The structure also includes a digital signal processing module for implementing digital filtering, demodulation, and quantum state determination.

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