A stable and traceable picowatt-level low-light generation device

Abstract

This invention relates to the field of optical precision measurement technology, and particularly to a stable and traceable picowatt-level weak light generation device and method, comprising: a light source unit, including a fiber laser and an acousto-optic modulator connected in sequence, for generating and outputting an initial beam with stable optical power; a beam splitting unit, including a fiber beam splitter, the input end of which is connected to the output end of the light source unit; the beam splitting unit is used to split the received beam into a first beam and a second beam based on a preset splitting ratio, and output them from a first output port and a second port of the beam splitting unit, respectively; an attenuation unit, the input end of which is connected to the second output port of the beam splitting unit, for attenuating the second beam to obtain a picowatt-level beam; and a temperature stabilization unit for controlling the temperature of the beam splitting unit and the attenuation unit based on a expected temperature. Compared with the prior art, this invention improves the stability of generating picowatt-level weak light.

Description

Technical Field

[0001] This invention relates to the field of optical precision measurement technology, and in particular to a stable and traceable picowatt-level weak light generation device. Background Technology

[0002] Optical power measurement, a commonly used technique for testing and calibrating optical systems, plays a crucial role in scientific research and engineering applications. To meet the measurement needs of different optical powers, existing measurement methods are mainly divided into those based on thermal principles and those based on photoelectric principles. Thermal-based methods determine optical power by detecting the temperature rise of the absorber caused by the absorption of the light beam; while photoelectric-based methods use photoelectric detection elements to convert optical signals into electrical signals for measurement. Compared to thermal methods, photoelectric measurement methods have significant advantages in sensitivity and response speed, and are currently the more commonly used technique in this field.

[0003] However, the aforementioned existing technologies all have significant drawbacks when measuring weak light signals. First, measurement methods based on thermal principles are limited by poor sensitivity and long response times, making them difficult to apply to the measurement of weak signals. Second, although commonly used commercial optoelectronic power meters have improved response speed, their lower limit for optical power measurement and measurement accuracy are still difficult to exceed the picowatt (pW) level, making them unsuitable for precise measurements in the field of weak light power. Summary of the Invention

[0004] To overcome the shortcomings of the prior art in measuring weak light signals, the present invention provides a stable and traceable picowatt-level weak light generation device.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A stable and traceable picowatt-level low-light generation device, the generation device comprising: The light source unit includes a fiber laser 1 and an acousto-optic modulator 2 connected in sequence, used to generate and output an initial beam with stable optical power; The beam splitting unit includes an optical fiber beam splitter 3, the input end of which is connected to the output end of the light source unit; the beam splitting unit is used to split the received beam into a first beam and a second beam based on a preset beam splitting ratio and output them from the first output port and the second output port of the beam splitting unit respectively. An attenuation unit, whose input end is connected to the second output port of the beam splitting unit, is used to attenuate the second beam to obtain a picowatt-level beam; A temperature stabilization unit is used to control the temperature of the spectral splitting unit and the attenuation unit based on a desired temperature.

[0006] As a preferred embodiment, the temperature stabilization unit includes a sealed enclosure 12, a temperature sensor, a heating element, and a temperature controller; The beam splitting unit and the attenuation unit are disposed inside the sealed enclosure 12; The temperature sensor is connected to the temperature controller, and the temperature controller is connected to the heating element to adjust the output power of the heating element.

[0007] As a preferred embodiment, the attenuation unit includes an optical fiber attenuator 4.

[0008] This application also proposes a method for measuring picowatt-level light, used to measure picowatt-level light generated by a stable and traceable picowatt-level weak light generating device, wherein the generating device further includes a detection unit, and the method includes: The first optical power value is obtained by detecting the first beam using the detection unit and converted into a first voltage signal. A radio frequency signal is generated based on the difference between the first voltage signal and a preset voltage. The optical power value of the picowatt-level beam is calculated based on the attenuation coefficient of the attenuation unit, the preset splitting ratio, and the first optical power value.

[0009] As a preferred embodiment, the detection unit includes an optical power meter 5.

[0010] As a preferred embodiment, the generating device further includes a light source modulation feedback module, which is used to receive the first voltage signal, generate a radio frequency signal based on the difference between the voltage signal and a preset voltage, and perform amplitude modulation on the acousto-optic modulator 2 based on the radio frequency signal.

[0011] As a preferred embodiment, the light source modulation feedback module includes a proportional-integral-derivative controller 6 and a signal generator 7; The input terminal of the proportional-integral-derivative controller 6 receives the voltage signal output by the detection unit, the output terminal of the proportional-integral-derivative controller 6 is connected to the signal generator 7, and the output terminal of the signal generator 7 is connected to the modulation port of the acousto-optic modulator 2 and outputs a radio frequency signal.

[0012] As a preferred embodiment, the device further includes a photoelectric conversion unit for receiving the picowatt-level beam and converting it into a second voltage signal; wherein, the gain coefficient of the photoelectric conversion unit is calculated based on the second voltage signal and the first voltage signal, and the optical power value of the picowatt-level beam is calculated based on the gain coefficient.

[0013] As a preferred embodiment, the photoelectric conversion unit includes a photodiode 8, a transimpedance amplifier 9, a filter 10, and a digital multimeter 11 connected in sequence.

[0014] As a preferred embodiment, the method further includes converting the picowatt-level beam into a second voltage signal based on photoelectric conversion, and calibrating the photoelectric conversion coefficient. The calibration steps are as follows: The first optical power value of the first beam is changed by adjusting the initial beam or the radio frequency signal; Multiple sets of first and second voltage signals are acquired simultaneously and linearly fitted. The slope of the linearly fitted line is extracted as the photoelectric conversion gain coefficient.

[0015] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: This invention utilizes temperature-stable beam splitting and attenuation units, combined with stable optical power, to obtain stable and traceable picowatt-level weak light; and the weak light power value can be obtained directly by measuring the stronger optical power through the detection unit, thus obtaining accurate picowatt-level weak light power and improving the accuracy and simplicity of the generated weak light. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the architecture of a stable and traceable picowatt-level low-light generation device in Example 1. Figure 2 This is a schematic diagram of the stable and traceable picowatt-level low-light generation device of Example 1. Figure 3 This is a flowchart of the measurement method in Example 2; Figure 4 This is a graph showing the dark voltage measurement results after photoelectric detection in Example 2; Figure 5 The linear fitting curves of the first and second voltage signals in Example 2; Among them, 1-fiber laser, 2-acoustic-optic modulator, 3-fiber beam splitter, 4-fiber attenuator, 5-optical power meter, 6-proportional-integral-differential controller, 7-signal generator, 8-photodiode, 9-transimpedance amplifier, 10-filter, 11-digital multimeter, 12-sealed enclosure. Detailed Implementation

[0017] In the embodiments of this application, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of this application. However, they do not mean that the applicant has used or necessarily used the solution.

[0018] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Example 1 This embodiment proposes a stable and traceable picowatt-level low-light generation device, such as... Figure 1 The diagram shown is a schematic of a stable and traceable picowatt-level low-light generation device architecture according to this embodiment.

[0021] The stable and traceable picowatt-level low-light generation device proposed in this embodiment includes: The light source unit includes a fiber laser 1 and an acousto-optic modulator 2 connected in sequence, used to generate and output an initial beam with stable optical power; The beam splitting unit includes an optical fiber beam splitter 3, the input end of which is connected to the output end of the light source unit; the beam splitting unit is used to split the received beam into a first beam and a second beam based on a preset beam splitting ratio and output them from the first output port and the second output port of the beam splitting unit respectively. An attenuation unit, whose input end is connected to the second output port of the beam splitting unit, is used to attenuate the second beam to obtain a picowatt-level beam; A temperature stabilization unit is used to control the temperature of the spectral splitting unit and the attenuation unit based on a desired temperature.

[0022] In this embodiment, an initial light beam is generated by a light source unit, which then splits the beam at a fixed ratio via a beam splitting unit and attenuates it to the picowatt level via an attenuation unit. At the same time, a temperature stabilization unit ensures that key parameters such as the beam splitting ratio and attenuation coefficient are not affected by changes in ambient temperature, thus guaranteeing the long-term stability of the system.

[0023] In an optional embodiment, the temperature stabilization unit includes a sealed enclosure 12, a temperature sensor, a heating element, and a temperature controller; The beam splitting unit and the attenuation unit are disposed inside the sealed enclosure 12; The temperature sensor is connected to the temperature controller, and the temperature controller is connected to the heating element to adjust the output power of the heating element.

[0024] As an example, the temperature stabilization unit controls the temperature inside the chamber based on the PID temperature control program of LabVIEW. Specifically, the temperature is measured by a digital multimeter 11 and converted into the corresponding temperature at the temperature control point inside the chamber. This temperature is then compared with the set temperature. When the temperature is lower than the set temperature, the system heats the silicone heating element through a voltage source, and the PID control parameters control the heating power. When the temperature is higher than the set temperature, heating stops and passive heat dissipation is performed.

[0025] like Figure 2 The diagram shown is a schematic representation of the picowatt-level low-light generation device in this embodiment.

[0026] In an alternative embodiment, the attenuation unit includes an optical fiber attenuator 4.

[0027] Example 2 This embodiment proposes a picowatt-level light measurement method for measuring the picowatt-level light generated by the stable and traceable picowatt-level weak light generating device proposed in Embodiment 1. The generating device further includes a detection unit, such as... Figure 3 The diagram shown is a flowchart of a picometer-level optical measurement method; the method includes: The first optical power value is obtained by detecting the first beam using the detection unit and converted into a first voltage signal. A radio frequency signal is generated based on the difference between the first voltage signal and a preset voltage. The optical power value of the picowatt-level beam is calculated based on the attenuation coefficient of the attenuation unit, the preset splitting ratio, and the first optical power value.

[0028] Alternatively, the detection unit may include an optical power meter 5.

[0029] In this embodiment, the detection unit monitors the first beam in real time and converts it into a voltage signal. Through a preset attenuation relationship, stable and measurable picowatt-level light can be obtained.

[0030] In an optional embodiment, the generating device further includes a light source modulation feedback module, which is used to receive the first voltage signal, generate a radio frequency signal based on the difference between the voltage signal and a preset voltage, and perform amplitude modulation on the acousto-optic modulator 2 based on the radio frequency signal.

[0031] In this embodiment, a precise measurement of picowatt-level weak light signals was achieved by constructing an active feedback control device.

[0032] In an optional embodiment, the light source modulation feedback module includes a proportional-integral-derivative controller 6 and a signal generator 7; The input terminal of the proportional-integral-derivative controller 6 receives the voltage signal output by the detection unit, the output terminal of the proportional-integral-derivative controller 6 is connected to the signal generator 7, and the output terminal of the signal generator 7 is connected to the modulation port of the acousto-optic modulator 2 and outputs a radio frequency signal.

[0033] In this embodiment, a proportional-integral-derivative (PID) controller is used as the feedback core. An internal reference voltage signal is input to the PID controller. The PID controller compares the analog voltage signal of the optical power meter 5 with the internally set reference voltage signal and modulates the amplitude of the signal generator 7 that drives the acousto-optic modulator 2. This makes the voltage signal output by the optical power meter 5 consistent with the internal reference voltage signal, thereby stabilizing the optical power of the system.

[0034] In an optional embodiment, the device further includes a photoelectric conversion unit for receiving the picowatt-level beam and converting it into a second voltage signal; wherein, the gain coefficient of the photoelectric conversion unit is calculated based on the second voltage signal and the first voltage signal, and the optical power value of the picowatt-level beam is calculated based on the gain coefficient.

[0035] In this embodiment, the obtained weak light power is correlated with voltage and linearly fitted using a photoelectric conversion system. This provides another method for measuring picowatt-level optical power using photoelectric principles. Specifically, by fitting the curve, the received optical power can be obtained from the voltage value output by the photoelectric conversion system. This extends the measurement of optical power to the picowatt-level weak light power range, which is not covered by commonly used commercial optical power meters. Furthermore, all the components used are commonly used experimental instruments, can be operated at room temperature, and are low in cost.

[0036] Alternatively, the photoelectric conversion unit includes a photodiode 8, a transimpedance amplifier 9, a filter 10, and a digital multimeter 11 connected in sequence.

[0037] In an optional embodiment, the method further includes converting the picowatt-level beam into a second voltage signal based on photoelectric conversion, and calibrating the photoelectric conversion coefficient, the calibration steps of which are as follows: The first optical power value of the first beam is changed by adjusting the initial beam or the radio frequency signal; Multiple sets of first and second voltage signals are acquired simultaneously and linearly fitted. The slope of the linearly fitted line is extracted as the photoelectric conversion gain coefficient.

[0038] More specifically, by measuring the beam splitter's splitting ratio attenuation coefficient and optical power meter reading 5 Through relational formulas After obtaining the optical power value output by the attenuator, the relationship is simplified, and a new attenuation coefficient is defined. The ratio of the optical power measured at point 5 of the optical power meter to the optical power measured after the attenuator is expressed as: .

[0039] Using the error propagation formula, the attenuated optical power The uncertainty expression is: The sources of uncertainty in each part include Type A uncertainty and Type B uncertainty.

[0040] As an example, optical power measurement The center value is 10.04 nW, and the standard combined relative uncertainty is 1.51%; attenuation coefficient The center value is 1016.56, and the standard composite relative uncertainty is 2.12%. Therefore, the optical power output by the weak light source is... The center value is 9.88 pW, the standard synthesis relative uncertainty is 2.60%, and the coverage factor is obtained. In this case, the measurement expression at approximately 10 pW optical power is (9.88 ± 0.51) pW.

[0041] like Figure 4 The image shown is a graph of the dark voltage measurement results after photoelectric detection. like Figure 5 As shown, this is the linear fitting curve of the first voltage signal and the second voltage signal.

[0042] pass Figure 5 The slope of the coefficient represents the photoelectric conversion coefficient of the photoelectric conversion system, and the intercept represents the dark voltage noise of the photoelectric conversion system. The weak light power of the corresponding output voltage can be quickly obtained through this coefficient, realizing the measurement of picowatts and weak light power.

[0043] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0044] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium such as ROM / RAM, magnetic disk, or optical disk, and includes several instructions to enable a terminal, such as a mobile phone, computer, server, air conditioner, or network device, to execute the methods described in the various embodiments of this application.

[0045] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A stable and traceable picowatt-level low-light generation device, characterized in that, The generating apparatus includes: The light source unit includes a fiber laser (1) and an acousto-optic modulator (2) connected in sequence, for generating and outputting an initial beam with stable optical power; The beam splitting unit includes an optical fiber beam splitter (3), the input end of which is connected to the output end of the light source unit; the beam splitting unit is used to split the received beam into a first beam and a second beam based on a preset beam splitting ratio and output them from the first output port and the second output port of the beam splitting unit respectively. An attenuation unit, whose input end is connected to the second output port of the beam splitting unit, is used to attenuate the second beam to obtain a picowatt-level beam; A temperature stabilization unit is used to control the temperature of the spectral splitting unit and the attenuation unit based on a desired temperature.

2. The stable and traceable picowatt-level weak light generation device according to claim 1, characterized in that, The temperature stabilization unit includes a sealed enclosure (12), a temperature sensor, a heating element, and a temperature controller; The beam splitting unit and the attenuation unit are disposed inside the sealed enclosure (12); The temperature sensor is connected to the temperature controller, and the temperature controller is connected to the heating element to adjust the output power of the heating element.

3. The stable and traceable picowatt-level weak light generation device according to claim 1, characterized in that, The attenuation unit includes an optical fiber attenuator (4).

4. A method for measuring picowatt-level light, used to measure picowatt-level light generated by the stable and traceable picowatt-level weak light generating device according to any one of claims 1 to 3, characterized in that, The generating device further includes a detection unit, and the method includes: The first optical power value is obtained by detecting the first beam using the detection unit and converted into a first voltage signal. A radio frequency signal is generated based on the difference between the first voltage signal and a preset voltage. The optical power value of the picowatt-level beam is calculated based on the attenuation coefficient of the attenuation unit, the preset splitting ratio, and the first optical power value.

5. The picometer-level optical measurement method according to claim 4, characterized in that, The detection unit includes an optical power meter (5).

6. The picometer-level optical measurement method according to claim 4, characterized in that, The generating device further includes a light source modulation feedback module, which is used to receive the first voltage signal, generate a radio frequency signal based on the difference between the voltage signal and a preset voltage, and perform amplitude modulation on the acousto-optic modulator (2) based on the radio frequency signal.

7. The picometer-level optical measurement method according to claim 6, characterized in that, The light source modulation feedback module includes a proportional-integral-derivative controller (6) and a signal generator (7). The input terminal of the proportional-integral-derivative controller (6) receives the voltage signal output by the detection unit. The output terminal of the proportional-integral-derivative controller (6) is connected to the signal generator (7). The output terminal of the signal generator (7) is connected to the modulation port of the acousto-optic modulator (2) and outputs a radio frequency signal.

8. The picometer-level optical measurement method according to claim 6, characterized in that, The device further includes a photoelectric conversion unit for receiving the picowatt-level beam and converting it into a second voltage signal; wherein, the gain coefficient of the photoelectric conversion unit is calculated based on the second voltage signal and the first voltage signal, and the optical power value of the picowatt-level beam is calculated based on the gain coefficient.

9. The picometer-level optical measurement method according to claim 8, characterized in that, The photoelectric conversion unit includes a photodiode (8), a transimpedance amplifier (9), a filter (10), and a digital multimeter (11) connected in sequence.

10. The picometer-level optical measurement method according to claim 9, characterized in that, The method also converts the picowatt-level beam into a second voltage signal based on photoelectric conversion, and performs photoelectric conversion coefficient calibration. The calibration steps are as follows: The first optical power value of the first beam is changed by adjusting the initial beam or the radio frequency signal; Multiple sets of first and second voltage signals are acquired simultaneously and linearly fitted. The slope of the linearly fitted line is extracted as the photoelectric conversion gain coefficient.

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