Photon analog-to-digital conversion method and converter based on optical trapping principle
By employing a photonic analog-to-digital conversion method based on the optical trapping principle, and utilizing multiple continuous optical signals and optical delay line control, high-precision on-chip photonic analog-to-digital conversion was achieved, solving the problem of optical power loss in traditional photonic analog-to-digital conversion systems and improving conversion accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI JIAOTONG UNIV
- Filing Date
- 2021-09-18
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional electronic analog-to-digital converters struggle to achieve high effective bit sampling and quantization of high-frequency analog signals, and on-chip photonic analog-to-digital conversion systems are affected by optical power loss, resulting in insufficient conversion accuracy.
A photonic analog-to-digital conversion method based on the optical trapping principle is adopted. The sampled analog signal is divided into multiple paths and loaded onto continuous optical signals of different wavelengths. The optical delay line is used to control the signal to enter the optical trapping unit at equal time intervals for time-domain discretization processing, thus avoiding the excessively high optical power nonlinear effect caused by directly synthesizing multiple continuous optical signals.
This improved the total input power of the photonic analog-to-digital conversion system, effectively offsetting the effects of optical power loss and achieving high-precision on-chip photonic analog-to-digital conversion.
Smart Images
Figure CN115840320B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to photonic information processing technology, specifically a photonic analog-to-digital conversion method and converter based on the principle of optical capture. Background Technology
[0002] Signals in nature are all continuously changing analog signals. Analog signals face problems during transmission and processing, such as susceptibility to distortion, poor anti-interference capabilities, and difficulty in storage and processing. Discretizing analog signals into digital signals can solve these problems, which has led to the arrival of the digital age and the era of big data. Analog-to-digital converters (ADCs) are the core devices connecting analog and digital signals. With the development and progress of the information society, human demand for information volume and speed is increasing, and the performance of ADCs is constantly being upgraded.
[0003] Traditional analog-to-digital converters (ADCs) are designed and implemented based on electronic technology, i.e., electronic ADCs. However, due to limitations such as aperture jitter and relative blurring, electronic ADCs struggle to achieve high effective bit sampling and quantization of high-frequency analog signals. Furthermore, the sampling rate of electronic ADCs is also limited by the constraints of high-speed clock generation technology, resulting in a "technical bottleneck" for traditional electronic ADCs.
[0004] Photonic analog-to-digital converter (A / D) technology, born from the advantages of photonics, boasts numerous benefits such as high sampling rates, large analog input bandwidth, and low timing jitter, making it an important direction for A / D converter research and development. Since the birth of photonic A / D technology, researchers have proposed numerous schemes. Among them, the photonic sampling-electro-quantization type A / D system combining high-speed broadband photonic sampling and high-precision electronic quantization has become the most mature and mainstream technical solution [Ghelfi, P., et al., “A fully photonics-based coherent radar system.” Nature, 507, 341-345, 2014.]. This type of scheme typically uses high-repetition-frequency optical pulses to achieve high-speed sampling, and then uses various optical demultiplexing methods (based on silicon photonic integrated photonic A / D converter chips, CN106933001B) to demultiplex the high-speed pulses into N low-speed optical pulses. Then, a photodetector completes photoelectric conversion, and an electro-quantizer completes the quantization encoding of the electrical signal. Finally, in the digital signal processing unit, the N digital signals are interleaved to recover the complete information of the original signal.
[0005] To overcome the shortcomings of discrete photonic analog-to-digital converters (ADCs) in terms of size, power consumption, and stability, the development of on-chip photonic ADCs is urgently needed. However, the biggest challenge facing on-chip photonic ADCs is on-chip optical power loss. Existing on-chip photonic ADCs are affected by on-chip optical power loss, either only achieving a low effective number of bits [A. Khilo, et al., "Photonic ADC: overcoming the bottleneck of electronicjitter." Optics Express. Vol. 20, No. 4, 4454-4469, 2012.], or sacrificing system integration to achieve a higher effective number of bits [Mehta, N., et al., "An Optically Sampled ADC in 3D Integrated Silicon-Photonics / 65nm CMOS." 2020 IEEE Symposium on VLSI Technology, 2020, 1-2.]. Therefore, there is an urgent need to optimize the design methods of photonic analog-to-digital conversion systems to offset the impact of on-chip optical power loss on the conversion accuracy of photonic analog-to-digital conversion systems, in order to truly realize high-precision on-chip photonic analog-to-digital conversion systems. Summary of the Invention
[0006] This invention proposes a photonic analog-to-digital conversion (ADC) method based on the optical trapping principle. This method utilizes multiple continuous light sources to load the sampled analog signal and controls the entry of each analog signal into the optical trapping unit at equal time intervals via an optical delay line, achieving signal discretization in the time domain. This method increases the total input power of the photonic ADC system by employing multiple continuous light sources. Furthermore, the multiple optical signals are modulated and delayed by the analog signal before being synthesized into a single signal, avoiding the excessively high total optical power and nonlinear effects caused by directly synthesizing multiple continuous light sources. This photonic ADC method based on the optical trapping principle overturns the traditional method of generating pulsed light before photonic sampling, increasing the total input power of the photonic ADC system and effectively offsetting the impact of optical power loss on the conversion accuracy. Based on this method, a high-precision on-chip photonic ADC system can be realized.
[0007] The technical solution of the present invention is as follows:
[0008] On the one hand, the present invention provides a photon analog-to-digital conversion method based on the optical trapping principle, characterized by comprising the following steps:
[0009] The sampled analog signal source is divided into N analog signals, and simultaneously loaded onto N continuous optical signals of different wavelengths, where N≥2;
[0010] Different delay amounts are obtained for N continuous optical signals of different wavelengths, and the delay difference between two adjacent signals is equal;
[0011] Synthesize N continuous optical signals of different wavelengths into a single continuous optical signal containing N wavelengths;
[0012] Simultaneously, the sampled signals loaded at different wavelengths are discretized in the time domain; and
[0013] A single signal with different wavelengths, after being discretized in the time domain, is divided into N optical signals according to wavelength.
[0014] Furthermore, it also includes the following steps:
[0015] The received N optical signals are converted into N electrical signals;
[0016] Convert N electrical signals into N digital electrical signals; and
[0017] The N-channel digital electrical signals are reconstructed and interleaved to obtain the original analog electrical signal information.
[0018] Furthermore, the N continuous optical signals of different wavelengths are generated by a continuous laser light source array (1).
[0019] Furthermore, the method of obtaining different delay amounts for N continuous optical signals of different wavelengths, with the delay difference between adjacent signals being equal, specifically involves controlling the relative delay of each signal to be 1 / Nfs, where the nth delay is (n-1) / Nfs, so that each of the same N sampled signals is staggered by 1 / Nfs in the time domain. Here, n = 1, 2, 3...N, and fs is the optical acquisition frequency.
[0020] On the other hand, the present invention also provides a photon analog-to-digital converter based on the optical trapping principle, characterized in that it includes:
[0021] A continuous laser source array generates N continuous laser beams of different wavelengths, which are then transmitted to a modulator array.
[0022] The radio frequency power divider module is used to divide the sampled signal source into N analog signals;
[0023] A modulator array is used to simultaneously load N analog signals onto N continuous optical signals of different wavelengths.
[0024] An optical delay line array is used to obtain different delay amounts for N continuous optical signals of different wavelengths, and the delay difference between two adjacent signals is equal.
[0025] A wavelength division multiplexer is used to combine N continuous optical signals of different wavelengths into a single continuous optical signal containing N wavelengths.
[0026] An optical acquisition module is used to simultaneously perform time-domain discretization processing on sampled signals loaded with different wavelengths; and
[0027] Wavelength demultiplexer is used to divide a single signal with different wavelengths, which has been synchronously discrete in the time domain, into N channels according to wavelength.
[0028] Furthermore, it also includes:
[0029] A photodetector array is used to convert N received optical signals into N electrical signals and transmit them to an electronic analog-to-digital converter array.
[0030] An electronic analog-to-digital converter array is used to convert N received electrical signals into N electrical digital signals and transmit them to a data integration and processing module; and
[0031] The data integration and processing module is used to reconstruct, interleave, and process the received N channels of digital electrical signals to obtain the original analog electrical signal information.
[0032] Furthermore, the modulator array consists of N parallel modulators, used to load N sampled analog signals onto N continuous lasers with different wavelengths.
[0033] Furthermore, the optical delay line array is composed of N parallel optical delay line units, and the relative delay of each optical delay line unit is controlled to be 1 / Nfs, wherein the delay amount generated by the nth optical delay line unit is (n-1) / Nfs, where n = 1, 2, 3...N, and fs is the optical capture frequency.
[0034] Furthermore, the modulator array consists of N identical modulators, the photodetector array consists of N PD units arranged in parallel, and the electronic analog-to-digital converter array consists of N electronic analog-to-digital converters arranged in parallel.
[0035] The continuous laser source, which serves as the optical carrier of the optical trapped photon analog-to-digital conversion system, can be, but is not limited to, a solid-state laser, a gas laser, or a semiconductor laser.
[0036] The sampled signal source is an electrical analog signal generated by a voltage-controlled oscillator, frequency synthesizer, analog signal generator, or arbitrary waveform generator.
[0037] The modulator is used to modulate the sampled signal source onto an optical carrier. The modulator may be, but is not limited to, a lithium niobate electro-optic modulator, a polymer electro-optic modulator, a silicon-based integrated electro-optic modulator, an acousto-optic modulator, or a spatial light modulator.
[0038] The optical delay line is used to generate a delay amount with a defined optical path length, and can be, but is not limited to, optical fibers, optical waveguides, or adjustable delay lines of a defined length.
[0039] The aforementioned radio frequency power divider module is used to divide the sampled signal source into N channels. It can be an active radio frequency power divider module or a passive radio frequency power divider module, and the power of each channel can be distributed uniformly or unevenly.
[0040] The wavelength division multiplexer is used to combine continuous lasers of different wavelengths into one channel. It can be, but is not limited to, fused taper fiber type wavelength division multiplexer, interference filter type wavelength division multiplexer, diffraction grating type wavelength division multiplexer, integrated optical waveguide type wavelength division multiplexer, etc.
[0041] The optical capture module is used to discretize the sampled signal modulated onto the optical carrier in the time domain, and can be, but is not limited to, a cascaded modulator or an optical microcavity.
[0042] The aforementioned wave demultiplexer is used to decompose a single optical path into different wavelength channels. It can be, but is not limited to, fused taper fiber type wave demultiplexer, interference filter type wave demultiplexer, diffraction grating type wave demultiplexer, integrated optical waveguide type wave demultiplexer, etc.
[0043] The PD unit is used to convert optical signals into electrical signals, and can be, but is not limited to, PIN diodes, APD diodes, silicon-germanium photodetectors, etc.
[0044] The electronic analog-to-digital converter is used to quantize and encode electrical signals, and can be an oscilloscope, ADC chip, or signal development board, etc.
[0045] The data integration and processing module is used for the reconstruction, interleaving, and processing of electrical digital signals, and can be implemented using computers, microcontrollers, information processing boards, etc.
[0046] The technical effects of this invention are as follows:
[0047] 1) The use of multiple continuous light sources increases the total input power of the photonic analog-to-digital conversion system. On the other hand, multiple optical signals are modulated and delayed before being combined into one, which avoids the nonlinear effect caused by excessive total optical power due to direct synthesis of multiple continuous light sources.
[0048] 2) It overturns the traditional photonic analog-to-digital conversion method of first generating pulsed light and then performing photon sampling, which improves the total input power of the photonic analog-to-digital conversion system and can effectively offset the impact of optical power loss on the conversion accuracy of the photonic analog-to-digital conversion system.
[0049] 3) By increasing the total input power of the system and effectively offsetting optical power loss, it becomes possible to realize a high-precision on-chip photonic analog-to-digital conversion system. Attached Figure Description
[0050] Figure 1 This is an overall architecture diagram of an embodiment of a photon analog-to-digital conversion method based on the optical trapping principle of the present invention;
[0051] Figure 2(a) is a schematic diagram of N sampled signals that are staggered by 1 / Nfs time in the time domain; Figure 2(b) is a schematic diagram of the optical acquisition module performing time-domain discretization processing on sampled signals loaded at different wavelengths simultaneously at the acquisition frequency fs; Figure 2(c) is a schematic diagram of the data integration and processing module reconstructing and interleaving N electrical-digital signals to obtain the original electrical-analog signal information. Detailed Implementation
[0052] A specific embodiment of this invention is given below with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of this invention, and provides detailed implementation methods and processes, but the scope of protection of this invention is not limited to the following embodiment.
[0053] Please see Figure 1 , Figure 1This is an overall architecture diagram of an embodiment of a photonic analog-to-digital conversion method based on the optical trapping principle of the present invention. As shown in the diagram, the photonic analog-to-digital conversion method based on the optical trapping principle of the present invention includes a continuous laser source array 1, a sampled signal source 2, a modulator array 3, an optical delay line array 4, a radio frequency power divider module 5, an optical trapping module 6, a wavelength division multiplexer 7, a wavelength demultiplexer 8, a photodetector array 9, an electronic analog-to-digital converter array 10, and a data integration and processing unit 11. The continuous laser source array 1 consists of N continuous laser sources 1-1 with different wavelengths; the modulator array 3 consists of N identical modulators 3-1; the optical delay line array 4 consists of N optical delay line units 4-1; the photodetector array 9 consists of N PD units 9-1 arranged in parallel; and the electronic analog-to-digital converter array 10 consists of N electronic analog-to-digital converters 10-1 arranged in parallel. The N output terminals of the continuous laser source array 1 are respectively connected to the first input terminals of the N modulators 3-1 in the modulator array 3. The sampled signal source 2 is connected to the input terminal of the RF power divider module 5. The N output terminals of the RF power divider module 5 are respectively connected to the second input terminals of the N modulators 3-1 in the modulator array 3. The output terminals of the N modulators 3-1 in the modulator array 3 are respectively connected to the input terminals of the N optical delay line units 4-1 in the optical delay line array 4. The output terminals of the N optical delay line units 4-1 in the optical delay line array 4 are respectively connected to the N channel ports of the wavelength division multiplexer 7. The multiplexed output of the wavelength division multiplexer 7... The output terminal of the optical acquisition module 6 is connected to the input terminal of the wave demultiplexer 8. The N output channels of the wave demultiplexer 8 are respectively connected to the input terminals of the N PD units 9-1 in the photodetector array 9. The output terminals of the N PD units 9-1 in the photodetector array 9 are respectively connected to the input terminals of the N electronic analog-to-digital converters 10-1 in the electronic analog-to-digital converter array 10. The output terminals of the N electronic analog-to-digital converters 10-1 in the electronic analog-to-digital converter array 10 are respectively connected to the N input terminals of the data integration and processing module 11, where N is a positive integer greater than or equal to 2.
[0054] The implementation process of the above-mentioned photon analog-to-digital conversion method based on the optical trapping principle includes the following steps:
[0055] 1) The sampled signal source 2 is divided into N paths by the radio frequency power divider module 5, and then loaded onto N continuous lasers 1-1 with different wavelengths via N modulators 3-1 in the modulator array 3. The N continuous lasers loaded with the same sampled signal are respectively input into N optical delay line units 4-1 in the optical delay line array 4, controlling the relative delay of each of the N optical delay line units 4-1 to be 1 / Nfs. The delay generated by the nth optical delay line unit is (n-1) / Nfs. This causes each of the originally identical N sampled signals to be staggered by 1 / Nfs in the time domain, as shown in Figure 2(a). Where n = 1, 2, 3...N, and fs is the optical capture frequency;
[0056] 2) The N delayed optical signals are combined into a single beam by the wavelength division multiplexer 7 and then enter the optical acquisition module 6. The optical acquisition module 6 simultaneously performs time-domain discretization processing on the sampled signals loaded at different wavelengths at an acquisition frequency of fs, as shown in Figure 2(b). The time-domain discretized optical signal is then divided into N paths according to wavelength by the wavelength demultiplexer 8.
[0057] 3) The N time-domain discretized optical signals are converted into N electrical signals by N PD units 9-1. These N electrical signals are then converted into N digital electrical signals by N electronic analog-to-digital converters 10-1. The N digital electrical signals are input to the data integration and processing module 11. This module reconstructs, interleaves, and processes the received N digital electrical signals to obtain the original analog electrical signal information, as shown in Figure 2(c). In this embodiment, N = 4.
[0058] In the above process, by pre-staggering the N sampled signals and then simultaneously optically capturing them in the time domain, photonic analog-to-digital conversion (A / D conversion) with a total sampling rate of N*fs is achieved. Experiments show that the photonic A / D conversion method based on the optical capture principle of this invention uses N continuous laser sources to increase the total input optical power of the photonic A / D conversion system, effectively offsetting the impact of optical power loss on the conversion accuracy. This invention proposes a novel photonic A / D conversion method that can provide a reliable technical solution for realizing high-precision on-chip photonic A / D conversion systems in the future.
Claims
1. A photonic analog-to-digital conversion method based on the principle of optical trapping, characterized in that, Including the following steps: The sampled analog signal source is divided into N analog signals, and simultaneously loaded onto N continuous optical signals of different wavelengths, where N≥2; Different delay amounts are obtained for N continuous optical signals of different wavelengths, and the delay difference between two adjacent signals is equal; Synthesize N continuous optical signals of different wavelengths into a single continuous optical signal containing N wavelengths; Simultaneously, the sampled signals loaded at different wavelengths are discretized in the time domain; A single signal with different wavelengths, after synchronous time-domain discretization, is divided into N optical signals according to wavelength. The received N optical signals are converted into N electrical signals; Convert N electrical signals into N digital electrical signals; The N-channel digital electrical signals are reconstructed and interleaved to obtain the original analog electrical signal information.
2. The photonic analog-to-digital conversion method based on the principle of optical trapping according to claim 1, characterized in that, The N-channel continuous optical signals of different wavelengths are generated by a continuous laser source array (1).
3. The photonic analog-to-digital conversion method based on the principle of optical trapping according to claim 1, characterized in that, The method of obtaining different delay amounts for N continuous optical signals of different wavelengths, with the delay difference between adjacent signals being equal, specifically involves controlling the relative delay of each signal to be 1 / Nfs, where the nth delay is (n-1) / Nfs, so that each of the same N sampled signals is staggered by 1 / Nfs in the time domain, where n=1, 2, 3...N, and fs is the optical acquisition frequency.
4. A photonic analog-to-digital converter based on the principle of optical trapping, characterized in that, include: A continuous laser source array (1) generates N continuous laser sources (1-1) of different wavelengths and transmits them to a modulator array (3). The radio frequency power divider module (5) is used to divide the sampled signal source (2) into N analog signals; The modulator array (3) is used to simultaneously load N analog signals onto N continuous optical signals of different wavelengths; Optical delay line array (4) is used to obtain different delay amounts for N continuous optical signals of different wavelengths, and the delay difference between adjacent channels is equal; A wavelength division multiplexer (7) is used to combine N continuous optical signals of different wavelengths into one continuous optical signal containing N wavelengths. The optical capture module (6) is used to simultaneously perform time-domain discretization processing on sampled signals loaded with different wavelengths; as well as Wavelength demultiplexer (8) is used to divide a single signal with different wavelengths that has been synchronously time-domain discrete into N channels according to wavelength; A photodetector array (9) is used to convert the received N electrical signals into N electrical signals and transmit them to an electronic analog-to-digital converter array (10). An electronic analog-to-digital converter array (10) is used to convert the received N electrical signals into N electrical digital signals and transmit them to the data integration and processing module (11). as well as The data integration and processing module (11) is used to reconstruct and interleave the received N-channel digital electrical signals and process them to obtain the original analog electrical signal information.
5. Photonic analog-to-digital converter based on the principle of optical trapping according to claim 4, characterized in that, The modulator array (3) consists of N parallel modulators (3-1) used to load N sampled analog signals onto N continuous lasers (1-1) with different wavelengths.
6. The photon analog-to-digital converter based on the optical trapping principle according to claim 4, characterized in that, The optical delay line array (4) consists of N parallel optical delay line units (4-1), and each optical delay line unit (4-1) is controlled to have a relative delay of 1 / Nfs. The delay amount generated by the nth optical delay line unit (4-n) is (n-1) / Nfs, where n=1, 2, 3...N, and fs is the optical capture frequency.
7. The photon analog-to-digital converter based on the optical trapping principle according to claim 4, characterized in that, The continuous laser source array (1) consists of N continuous laser sources (1-1) with different wavelengths, the modulator array (3) consists of N identical modulators (3-1), the photodetector array (9) consists of N PD units (9-1) arranged in parallel, and the electronic analog-to-digital converter array (10) consists of N electronic analog-to-digital converters (10-1) arranged in parallel.
8. The photon analog-to-digital converter based on the optical trapping principle according to claim 4, characterized in that, The optical capture module (6) is used to discretize the sampled signal modulated onto the optical carrier in the time domain, and can be, but is not limited to, a cascaded modulator or an optical microcavity.
9. The photon analog-to-digital converter based on the optical trapping principle according to claim 4, characterized in that, The optical delay line unit (4-1) is used to generate a delay amount with a defined optical path. The optical delay line may be, but is not limited to, an optical fiber, an optical waveguide, or an adjustable delay line of a defined length.
10. The photon analog-to-digital converter based on the optical trapping principle according to claim 4, characterized in that, The radio frequency power divider module (5) is an active radio frequency power divider module or a passive radio frequency power divider module, and the power of each channel is distributed evenly or unevenly.