Solution concentration detection device and method thereof

Abstract

A solution concentration detection device and a method thereof, wherein the solution concentration detection device comprises: a light source generating an initial light; a light splitter splitting the initial light into a detection light and a reference light; a double-path accommodating cavity, the double-path accommodating cavity comprising a to-be-detected solution accommodating cavity accommodating a to-be-detected solution and a reference solution accommodating cavity accommodating a reference solution; the detection light is transmitted through the to-be-detected solution to form a to-be-detected signal light; the reference light is transmitted through the reference solution to form a reference signal light; a detection processing module configured to obtain a phase difference between the to-be-detected signal light and the reference signal light; the detection processing module is further configured to obtain the concentration of the to-be-detected solution according to the phase difference and the concentration of the reference solution. By introducing a reference solution with a known concentration as a control path, comparing with the to-be-detected solution, and inverting the concentration of the to-be-detected solution through the phase difference between the to-be-detected signal light and the reference signal light, the accuracy of the solution concentration detection result can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of solution detection, and in particular to a solution concentration detection device and method. Background Technology

[0002] In many fields such as chemical production, food processing, pharmaceutical research and development, environmental monitoring, and semiconductor manufacturing, solution concentration, as a core parameter for characterizing the physicochemical properties of a system, directly determines product quality, process stability, and final application results.

[0003] Currently, solution concentration detection technology has formed a diversified system, which can be divided into two main categories based on the detection principle: chemical analysis methods and physical analysis methods. Among them, chemical analysis methods (such as titration and gravimetric methods) are widely used in traditional laboratory testing due to their mature principles and low cost. However, these methods have inherent drawbacks such as cumbersome operation, long detection cycle, consumption of chemical reagents, and susceptibility to secondary pollution. They also rely on professional operators and are difficult to meet the needs of online real-time detection and continuous monitoring in modern industrial production, especially unsuitable for high-cleanliness, fast-paced semiconductor processes or large-scale assembly line production scenarios.

[0004] To overcome the limitations of chemical analysis methods, physical analysis methods have gradually become the mainstream development direction in the field of concentration detection due to their advantages such as fast detection speed, no sample destruction, and non-contact measurement. The core principle of physical analysis methods is to utilize the changes in physical properties (such as density, viscosity, optical properties, and electrical properties) caused by changes in solution concentration, and to infer concentration information by detecting changes in relevant physical parameters. Among them, detection technologies based on optical properties are highly favored in high-precision concentration detection scenarios due to their outstanding advantages such as fast response speed, strong anti-interference ability, high detection accuracy, and easy integration.

[0005] However, the stability and accuracy of solution concentration detection technology using physical analysis methods need further improvement. Summary of the Invention

[0006] The problem addressed by this invention is how to improve the stability and accuracy of solution concentration detection.

[0007] To address the above problems, the present invention provides a solution concentration detection device, comprising:

[0008] A light source is configured to generate initial light; a beam splitter is configured to split the initial light into a detection light and a reference light; a dual-channel containment cavity includes a test solution containment cavity and a reference solution containment cavity, the test solution containment cavity being configured to contain the test solution and the reference solution containment cavity being configured to contain the reference solution; the detection light is incident on the test solution and transmitted through the test solution to form the test signal light; the reference light is incident on the reference solution and transmitted through the reference solution to form the reference signal light; a detection processing module is configured to obtain the phase difference between the test signal light and the reference signal light; the detection processing module is also configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution.

[0009] Optionally, the test solution container and the reference solution container of the dual-channel container are located in the same physical environment.

[0010] Optionally, the solution concentration detection device further includes: a coupler configured to couple the signal light to be measured and the reference signal light to form a coupled signal light; and a detection processing module obtaining the phase difference between the signal light to be measured and the reference signal light based on the coupled signal light.

[0011] Optionally, the light source is a linearly polarized light source.

[0012] Optionally, the light source includes at least one of a laser and an LED; the light source also includes a polarizer located in the optical path between the light source and the beam splitter.

[0013] Optionally, the detection processing module includes: an active tunable spectral unit configured to perform phase scanning on the coupled signal light to obtain a scanning signal light; a detector configured to receive the scanning signal light to obtain the light intensity of the scanning signal light; a processing unit configured to obtain the phase difference between the test signal light and the reference signal light based on the change in the light intensity of the scanning signal light; and a calculation unit configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution.

[0014] Optionally, the active tunable spectral unit includes at least one structure of a microring resonator and a Mach-Zehnder interferometer.

[0015] Optionally, the active tunable spectral unit includes: a beam splitter configured to split the coupled signal light into a local oscillator light and a light to be modulated; a modulator configured to modulate the phase of the light to be modulated to obtain modulated light; and a beam combiner configured to couple the modulated light and the local oscillator light to obtain scanning signal light.

[0016] Optionally, the modulator includes: a thermo-optical phase modulator.

[0017] Optionally, the detection and processing module further includes: a polarization separation rotator, which is configured to modulate the coupled signal light so that the modulated coupled signal light has a single electromagnetic wave transmission mode; and a beam splitter that splits the modulated coupled signal light into local oscillator light and light to be modulated.

[0018] Optionally, the detection processing module includes: an on-chip interferometric detection optical chip, which includes: an active tunable spectral unit and a polarization separation rotator.

[0019] Optionally, the active tunable spectral unit further includes: a mode separator configured to separate different electromagnetic wave transmission modes in the coupled signal light to obtain a first beam splitter and a second beam splitter; a mode modulator configured to modulate the electromagnetic wave transmission mode of at least one of the first beam splitter and the second beam splitter so that the modulated beam splitter has the same electromagnetic wave transmission mode, and the beam splitter is at least one of the first beam splitter and the second beam splitter; and a beam splitter further configured to couple the modulated beam splitter to obtain the modulated coupled signal light.

[0020] Optionally, the processing unit includes: a fitter configured to obtain a light intensity fitting curve based on the change in light intensity of the scanned signal light; and a comparator configured to compare the light intensity fitting curve with a pre-stored reference curve to obtain the phase difference between the signal light to be tested and the reference signal light.

[0021] Optionally, the calculation unit of the detection processing module includes: a first inverter configured to obtain the refractive index difference between the test solution and the reference solution based on the phase difference; and a second inverter pre-stored with a refractive index-concentration coefficient, configured to obtain the concentration of the test solution based on the refractive index difference, combined with the refractive index-concentration coefficient and the concentration of the reference solution.

[0022] Optionally, the first inverter pre-stores the length of the optical path to be measured and the length of the reference optical path, wherein the length of the optical path to be measured is the optical path length for transmitting the detection light from the solution to be measured, and the length of the reference optical path is the optical path length for transmitting the reference light from the reference solution; the first inverter obtains the refractive index difference between the solution to be measured and the reference solution based on the phase difference and in combination with the length of the optical path to be measured and the length of the reference optical path.

[0023] Accordingly, the present invention also provides a method for detecting solution concentration, comprising:

[0024] An initial light is generated; the initial light is divided into a detection light and a reference light; the detection light is incident on the solution to be tested and transmitted through the solution to form the signal light to be tested; the reference light is incident on the reference solution and transmitted through the reference solution to form the reference signal light; the phase difference between the signal light to be tested and the reference signal light is obtained; based on the phase difference and the concentration of the reference solution, the concentration of the solution to be tested is obtained.

[0025] Optionally, it also includes setting the test solution and the reference solution in the same physical environment.

[0026] Optionally, it also includes: before obtaining the phase difference between the signal light to be tested and the reference signal light, coupling the signal light to be tested and the reference signal light to form a coupled signal light; the step of obtaining the phase difference between the signal light to be tested and the reference signal light includes: obtaining the phase difference between the signal light to be tested and the reference signal light based on the coupled signal light.

[0027] Optionally, the step of generating initial light includes generating linearly polarized initial light.

[0028] Optionally, the steps of generating initial light include: generating original light; and converting the original light into linearly polarized initial light.

[0029] Optionally, the step of obtaining the phase difference between the test signal light and the reference signal light based on the coupled signal light includes: performing a phase scan on the coupled signal light to obtain a scan signal light; receiving the scan signal light to obtain the light intensity of the scan signal light; and obtaining the phase difference between the test signal light and the reference signal light based on the change in the light intensity of the scan signal light.

[0030] Optionally, the step of performing phase scanning on the coupled signal light to obtain the scanning signal light includes: dividing the coupled signal light into a local oscillator light and a light to be modulated; modulating the phase of the light to be modulated to obtain the modulated light; and coupling the modulated light and the local oscillator light to obtain the scanning signal light.

[0031] Optionally, the step of performing phase scanning on the coupled signal light to obtain the scanned signal light further includes: before dividing the coupled signal light into local oscillator light and light to be modulated, modulating the coupled signal light so that the modulated coupled signal light has a single electromagnetic wave transmission mode; the step of dividing the coupled signal light into local oscillator light and light to be modulated includes: dividing the modulated coupled signal light into local oscillator light and light to be modulated.

[0032] Optionally, the step of modulating the coupled signal light to give the modulated coupled signal light a single electromagnetic wave transmission mode includes: separating different electromagnetic wave transmission modes in the coupled signal light to obtain a first beam splitter and a second beam splitter; modulating the electromagnetic wave transmission mode of at least one of the first beam splitter and the second beam splitter to give the modulated beam splitter the same electromagnetic wave transmission mode, wherein the beam splitter is at least one of the first beam splitter and the second beam splitter; and coupling the modulated beam splitter to obtain the modulated coupled signal light.

[0033] Optionally, the step of obtaining the phase difference between the signal light to be tested and the reference signal light includes: obtaining a light intensity fitting curve based on the change in the light intensity of the scanning signal light; comparing the light intensity fitting curve with a pre-stored reference curve to obtain the phase difference between the signal light to be tested and the reference signal light.

[0034] Optionally, the step of obtaining the concentration of the test solution based on the phase difference and the concentration of the reference solution includes: obtaining the refractive index difference between the test solution and the reference solution based on the phase difference; and obtaining the concentration of the test solution based on the refractive index difference, a preset refractive index-concentration coefficient, and the concentration of the reference solution.

[0035] Optionally, the step of obtaining the refractive index difference between the test solution and the reference solution based on the phase difference includes: obtaining the refractive index difference between the test solution and the reference solution based on the phase difference, combined with the length of the optical path to be tested and the length of the optical path to be referenced; wherein, the length of the optical path to be tested is the optical path length for transmitting the detection light from the test solution, and the length of the optical path to be referenced is the optical path length for transmitting the reference light from the reference solution.

[0036] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0037] In this invention, the generated initial light is divided into a detection light and a reference light. The detection light is incident on the solution to be tested and transmitted through the solution to form a test signal light. The reference light is incident on the reference solution and transmitted through the solution to form a reference signal light. The test signal light and the reference signal light are coupled to form a coupled signal light. Based on the coupled signal light, the phase difference between the test signal light and the reference signal light is obtained, and then combined with the concentration of the reference solution, the concentration of the solution to be tested is obtained. By introducing a reference solution of known concentration as a control path to compare with the solution to be tested, and by using the phase difference between the test signal light and the reference signal light to invert the concentration of the solution to be tested, the accuracy of the solution concentration detection result can be effectively improved.

[0038] In an optional embodiment of this invention, the test solution chamber and the reference solution chamber of the dual-channel accommodating cavity are located in the same physical environment. By placing the test solution and the reference solution in the same physical environment, the influence of the environment on the test solution and the reference solution becomes common mode, which can effectively improve the stability of the detection results.

[0039] In an optional embodiment of the present invention, after forming the signal light to be tested and the reference signal light, the two signals are coupled to form a coupled signal light; the phase difference between the signal light to be tested and the reference signal light is obtained based on the coupled signal light. By coupling the signal light to be tested and the reference signal light, the common-mode effects on the two signals are canceled out, which can effectively improve the detection accuracy and the stability of the detection results.

[0040] In an optional embodiment of this invention, the linearly polarized initial light is divided into a detection light and a reference light, meaning both the detection light and the reference light are linearly polarized. Using linearly polarized light to detect the reference solution and the solution to be tested effectively improves the coupling efficiency of the resulting coupled signal light, effectively improves the signal-to-noise ratio, and is beneficial for improving detection accuracy and stability.

[0041] In an optional embodiment of the present invention, the phase difference between the signal light to be measured and the reference signal light is obtained based on phase scanning. Determining the phase difference through phase scanning, and thus the solution concentration, ensures both the sensitivity and accuracy of solution concentration detection, while also improving the signal-to-noise ratio, which is beneficial for improving the accuracy and stability of the concentration detection results.

[0042] In an optional embodiment of the present invention, during phase scanning, the coupled signal light is modulated so that the modulated coupled signal light has a single electromagnetic wave transmission mode. This single electromagnetic wave transmission mode ensures that the local oscillator light and the light to be modulated have the same electromagnetic wave transmission mode, thereby improving the coupling efficiency between the local oscillator light and the modulated light, effectively increasing the signal-to-noise ratio, and contributing to improved accuracy and stability of concentration detection results. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of a solution concentration detection device consistent with some embodiments of the present invention.

[0044] Figure 2 This is a schematic diagram of the detection and processing module in a solution concentration detection device consistent with some embodiments of the present invention.

[0045] Figure 3 This is a schematic diagram of the active tunable spectral unit of the detection processing module in a solution concentration detection device consistent with some embodiments of the present invention.

[0046] Figure 4 This is a functional block diagram of the processing unit and calculation unit of the detection processing module in a solution concentration detection device consistent with some embodiments of the present invention.

[0047] Figure 5 This is a schematic diagram of the light intensity fitting curve and reference curve obtained by a solution concentration detection device consistent with some embodiments of the present invention.

[0048] Figure 6 This is a schematic diagram of the active tunable spectral unit of the detection processing module in a solution concentration detection device consistent with some embodiments of the present invention.

[0049] Figure 7 This is a schematic flowchart of a solution concentration detection method consistent with some embodiments of the present invention.

[0050] Figure 8 This is a schematic flowchart of the initial light generation step in a solution concentration detection method consistent with some embodiments of the present invention.

[0051] Figure 9This is a schematic flowchart illustrating the steps of obtaining the phase difference between the target signal light and the reference signal light in a solution concentration detection method consistent with some embodiments of the present invention.

[0052] Figure 10 This is a schematic flowchart illustrating the step of phase scanning of the coupled signal light to obtain the scanning signal light in a solution concentration detection method consistent with some embodiments of the present invention.

[0053] Figure 11 This is a flowchart illustrating the step of modulating the coupled signal light in a solution concentration detection method consistent with some embodiments of the present invention, so that the modulated coupled signal light has a single electromagnetic wave mode.

[0054] Figure 12 This is a schematic flowchart illustrating the steps of obtaining the phase difference between the target signal light and the reference signal light in a solution concentration detection method consistent with some embodiments of the present invention.

[0055] Figure 13 This is a schematic flowchart illustrating the step of obtaining the concentration of the solution to be tested based on the phase difference and the concentration of the reference solution in a solution concentration detection method consistent with some embodiments of the present invention. Detailed Implementation

[0056] As can be seen from the background art, the solution concentration detection technology using physical analysis methods in the existing technology has the problem of needing further improvement in stability and accuracy.

[0057] Common solutions for solution concentration detection include Abbe refractometers, integrated optical sensors, and intensity demodulation sensors. Abbe refractometers measure solution concentration using the principle of total internal reflection critical angle, offering high accuracy but making automated online detection difficult. Integrated optical sensors, while highly sensitive, are typically based on optical path detection, meaning even small fluctuations in ambient temperature can cause significant drift in the results, greatly affecting accuracy and repeatability. Intensity demodulation sensors rely on changes in light intensity to infer solution concentration, making them highly susceptible to fluctuations in light source power and changes in optical path loss, resulting in poor signal-to-noise ratio.

[0058] To address the technical problem, this invention provides a solution concentration detection device, comprising: a light source configured to generate initial light; a beam splitter configured to split the initial light into a detection light and a reference light; a dual-channel containment cavity, including a test solution containment cavity and a reference solution containment cavity, the test solution containment cavity being configured to contain the test solution and the reference solution containment cavity being configured to contain a reference solution; the detection light is incident on the test solution and transmitted through the test solution to form a test signal light; the reference light is incident on the reference solution and transmitted through the reference solution to form a reference signal light; and a detection processing module configured to obtain the phase difference between the test signal light and the reference signal light; the detection processing module is further configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution.

[0059] The technical solution of this invention introduces a reference solution of known concentration as a control path to compare with the solution to be tested. By using the phase difference between the signal light to be tested and the reference signal light, the concentration of the solution to be tested can be inverted, which can effectively improve the accuracy of solution concentration detection results.

[0060] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0061] refer to Figure 1 The diagram shows a schematic representation of a solution concentration detection device consistent with some embodiments of the present invention.

[0062] The solution concentration detection device includes:

[0063] A light source is configured to generate initial light; a beam splitter is configured to split the initial light into a detection light and a reference light; a dual-channel containment cavity includes a test solution containment cavity and a reference solution containment cavity, the test solution containment cavity being configured to contain the test solution and the reference solution containment cavity being configured to contain the reference solution; the detection light is incident on the test solution and transmitted through the test solution to form the test signal light; the reference light is incident on the reference solution and transmitted through the reference solution to form the reference signal light; a detection processing module is configured to obtain the phase difference between the test signal light and the reference signal light; the detection processing module is also configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution.

[0064] The light source is configured to produce initial light.

[0065] In some embodiments of the present invention, the light source is a linearly polarized light source. Specifically, the initial light generated by the light source is linearly polarized light.

[0066] In some embodiments, the light source includes at least one of a laser and an LED; the light source also includes a polarizer located in the optical path between the light source and the beam splitter.

[0067] Specifically, one of the laser and the LED can generate raw light. The raw light can be natural light, and the polarizer can polarize the raw light, converting it into linearly polarized initial light.

[0068] like Figure 1 In some embodiments shown, the light source 110 includes a laser 111 and a polarizer 112, wherein the polarizer 112 is located in the optical path downstream of the laser 111. The original light 101 generated by the laser 111 is transmitted through the polarizer 112 to form linearly polarized initial light 102.

[0069] The beam splitter is configured to split the initial light into a detection beam and a reference beam.

[0070] Specifically, the beam splitter is located in the optical path downstream of the light source. The beam splitter receives the initial light generated by the light source and splits it into a detection beam and a reference beam.

[0071] For example, such as Figure 1 In some embodiments shown, the light source 110 includes a laser 111 and a polarizer 112 arranged sequentially along the optical path; a beam splitter 120 is located in the optical path downstream of the polarizer 112, and the beam splitter 120 splits the initial light 102 into a detection light 103 and a reference light 104. The beam splitter 120 is a polarization-maintaining beam splitter. The beam splitter 120 splits the linearly polarized initial light 102 into the linearly polarized detection light 103 and the linearly polarized reference light 104.

[0072] The dual-channel containment chamber is configured to contain the test solution and the reference solution.

[0073] Specifically, the dual-channel containment chamber includes a test solution containment chamber for containing the test solution and a reference solution containment chamber for containing the reference solution.

[0074] In some embodiments, the dual-channel containment chamber can be a dual-channel fluid cell. The dual-channel fluid cell includes two fluid cells. One fluid cell is a test solution containment chamber to contain the test solution, and the other fluid cell is a reference solution containment chamber to contain the reference solution.

[0075] In other embodiments of the present invention, the dual-channel receiving cavity can also be a dual-channel flow path. The dual-channel flow path includes two channels. One channel is a receiving cavity for the test solution, used to transport the test solution, and the other channel is a receiving cavity for the reference solution, used to transport the reference solution.

[0076] In some embodiments, the dual-channel containment chamber is a dual-channel flow path, with the test solution and the reference solution respectively transported through the two channels of the dual-channel flow path. The test solution and the reference solution are transported in their respective channels in a bubble-free and continuous flow manner, that is, the test solution and the reference solution are stably transported in their respective channels without bubble entrainment, retention or precipitation, and the flow process is continuous.

[0077] It should also be noted that the reference solution is a standard solution of known concentration. For example, the reference solution is pure water or a standard buffer solution.

[0078] In some embodiments of the present invention, the test solution container and the reference solution container of the dual-channel container are located in the same physical environment. Having the test solution container and the reference solution container in the same physical environment ensures that the test solution and the reference solution are in the same physical environment during the detection process, making the influence of environmental factors (such as temperature, pressure, vacuum, electromagnetic field, etc.) on the test solution and the reference solution common mode, thus effectively improving the stability of the detection results.

[0079] It should be noted that the test solution container and the reference solution container in the dual-channel container are in the same physical environment. This means that the test solution container and the reference solution container are located in the same chamber and share the same chamber shell. There is no structural design for heat insulation, pressure isolation or electromagnetic field shielding between the test solution container and the reference solution container, ensuring that the test solution container and the reference solution container are in exactly the same spatial area.

[0080] like Figure 1 In some embodiments shown, the detection light 103 and reference light 104 split by the beam splitter 120 are transmitted to the test solution receiving cavity 131 and the reference solution receiving cavity 132, respectively. The test solution in the test solution receiving cavity 131 transmits the detection light 103 to form the test signal light 105; the reference solution in the reference solution receiving cavity 132 transmits the reference light 104 to form the reference signal light 106. For example, the detection light 103 transmits through the test solution in the test solution receiving cavity 131 to form the test signal light 105. The reference light 104 transmits through the reference solution in the reference solution receiving cavity 132 to form the reference signal light 106.

[0081] In some embodiments of the present invention, the solution concentration detection device further includes: a coupler configured to couple a test signal light and a reference signal light to form a coupled signal light; and a detection processing module obtaining the phase difference between the test signal light and the reference signal light based on the coupled signal light. The coupler can couple the test signal light and the reference signal light, thereby canceling out the common-mode effects on the test signal light and the reference signal light, effectively improving detection accuracy and the stability of the detection results.

[0082] In some embodiments, the coupler is a polarization-maintaining coupler. During the process of coupling the test signal light and the reference signal light to form the coupled signal light, the polarization state of the signal light is not changed. For example, both the test signal light and the reference signal light are linearly polarized, and the coupled signal light is also linearly polarized. Using linearly polarized light to detect the reference solution and the test solution, forming linearly polarized test signal light and reference signal light, can effectively improve the coupling efficiency of forming the coupled signal light, effectively improve the signal-to-noise ratio, and is beneficial to improving detection accuracy and stability.

[0083] like Figure 1 In some embodiments shown, the coupler 150 is located in the optical path downstream of the dual-path receiving cavity 130. The coupler 150 has two receiving ends: one receiving end receives the test signal light 105 formed by the transmission of detection light 103 through the test solution in the test solution receiving cavity 131; the other receiving end receives the reference signal light 106 formed by the transmission of reference light 104 through the reference solution in the reference solution receiving cavity 132. The coupler 150 combines the received test signal light 105 with the test signal light 106. The combined test signal light 105 interferes with the test signal light 106, thereby forming a coupled signal light 107.

[0084] Continue to refer to Figure 1 The solution concentration detection device also includes a detection processing module. The detection processing module is configured to obtain the phase difference between the test signal light and the reference signal light, and based on the phase difference and the concentration of the reference solution, obtain the concentration of the test solution.

[0085] By introducing a reference solution of known concentration as a control path and comparing it with the solution to be tested, the concentration of the solution to be tested can be inverted by the phase difference between the signal light to be tested and the reference signal light, which can effectively improve the accuracy of solution concentration detection results.

[0086] In some embodiments of the present invention, the detection processing module includes: an active tunable spectral unit configured to perform phase scanning on the coupled signal light to obtain a scanning signal light; a detector configured to receive the scanning signal light to obtain the light intensity of the scanning signal light; a processing unit configured to obtain the phase difference between the test signal light and the reference signal light based on the change in the light intensity of the scanning signal light; and a calculation unit configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution.

[0087] The active tunable spectral unit performs phase scanning on the coupled signal light to form a scanning signal light, which is then received by a detector. The phase difference is then obtained by a processing unit. By determining the phase difference through phase scanning, the solution concentration can be determined. This method can ensure the sensitivity and accuracy of solution concentration detection, improve the signal-to-noise ratio, and enhance the accuracy and stability of concentration detection results.

[0088] like Figure 2 In some embodiments shown, in the detection processing module, an active tunable spectral unit 241 and a detector 242 are sequentially disposed in the optical path downstream of the coupler 250. The active tunable spectral unit 241 receives the coupled signal light 207 generated by the coupler 250; the active tunable spectral unit 241 performs phase scanning on the received coupled signal light 207 to obtain a scanning signal light 209; the detector 242 receives the scanning signal light 209 and performs photoelectric conversion on the scanning signal light 209 to obtain the light intensity of the scanning signal light 209, generating a light intensity electrical signal.

[0089] In some embodiments, the active tunable spectral unit includes at least one structure selected from micro-ring resonators (MRRs) and Mach-Zehnder interferometers (MZIs). Both micro-ring resonators and Mach-Zehnder interferometers are phase-sensitive structures, and this structure, when used to construct an active tunable spectral unit, can effectively ensure the realization and accuracy of phase scanning.

[0090] In some embodiments, the active tunable spectral unit includes: a beamsplitter configured to split the coupled signal light into a local oscillator light and a light to be modulated; a modulator configured to modulate the phase of the light to be modulated to obtain modulated light; and a beam combiner configured to couple the modulated light and the local oscillator light to obtain scanning signal light. Phase difference is determined by actively controlling the phase accumulation of the optical signal, converting the phase change into a measurable output signal (light intensity / wavelength shift), and then calculating the phase difference through inversion. By constructing an optical path using the beamsplitter and beam combiner, the modulator modulates only a portion of the coupled signal light, thereby achieving phase scanning.

[0091] Specifically, such as Figure 3In some embodiments shown, the active tunable spectral unit includes a Mach-Zehnder interferometer structure. The Mach-Zehnder interferometer structure is located in the optical path between beam splitter 341a and beam combiner 241c. The Mach-Zehnder interferometer structure includes a first optical path 341d for transmitting local oscillator light and a second optical path 341e for transmitting light to be modulated, wherein modulator 341b is located in the second optical path 341e. Beam splitter 341a splits the coupled signal light 307 into local oscillator light transmitted to the first optical path 341d and light to be modulated transmitted to the second optical path 341e. The local oscillator light is directly transmitted to beam combiner 341c via the first optical path 341d. When the light to be modulated is transmitted in the second optical path 341e, modulator 341b located in the second optical path 341e modulates the phase of the light to be modulated, forming modulated light transmitted to beam combiner 341c. The beam combiner 341c receives and couples the local oscillator light and the modulated light to form the scanning signal light 309.

[0092] It should be noted that in the structure of the Mach-Zehnder interferometer, at least one of the first and second optical paths can be implemented using an on-chip waveguide.

[0093] In some embodiments, the modulator includes a thermo-optic phase modulator. Thermo-optic phase modulators offer advantages such as high precision, low cost, and high response speed; using a thermo-optic phase modulator can control costs while ensuring phase scanning accuracy and speed. In other embodiments of the present invention, the modulator can also be other types of phase modulators such as electro-optic phase modulators, acousto-optic phase modulators, magneto-optic phase modulators, and all-optical phase modulators.

[0094] Specifically, such as Figure 3 In some embodiments shown, the modulator 341b in the second optical path 341e tunes the phase of the light to be modulated transmitted in the second optical path 341e under the control of the scanning signal to form modulated light.

[0095] It should be noted that, in some embodiments of the present invention, the solution concentration detection device includes a signal processing circuit configured to generate a scanning signal to control the tuning of the phase of the light to be modulated by the modulator. Specifically, the signal modulation circuit is connected to the modulator and provides a scanning signal (e.g., applies a scanning voltage) to the modulator to control the tuning of the phase of the light to be modulated by the modulator.

[0096] For example, the scanning signal generated by the signal modulator controls the modulator to perform a linear or stepped scanning of the phase of the light to be modulated, thereby causing the resulting modulated light to have a phase delay of 0 to 2π.

[0097] In some embodiments, the detection processing module further includes: a polarization beam splitter rotator, configured to modulate the coupled signal light so that the modulated coupled signal light has a single electromagnetic wave transmission mode; and a beam splitter that splits the modulated coupled signal light into a local oscillator beam and a beam to be modulated. The polarization beam splitter rotator (PBSR) can simultaneously perform "polarization separation" and "polarization rotation," separating the incident orthogonal polarization state (TE / TM) and rotating the target polarization state (e.g., TM) into a working polarization state (TE) before splitting the beam and outputting it to the beam splitter of the active tunable spectral unit for coupling and beam splitting. The polarization beam splitter rotator enables the coupled signal light received by the active tunable spectral unit to have a single electromagnetic wave transmission mode, thereby ensuring that the local oscillator beam and the beam to be modulated formed during phase scanning have the same electromagnetic wave transmission mode. This effectively improves the coupling efficiency between the local oscillator beam and the modulated beam, thereby effectively improving the signal-to-noise ratio and contributing to the improvement of the accuracy and stability of concentration detection results.

[0098] Specifically, such as Figure 2 In some embodiments shown, the polarization splitter rotator 245 is located in the optical path between the coupler 250 and the active tunable spectral unit 241. The polarization splitter rotator 245 receives the coupled signal light 207 obtained by the coupler 250 and modulates the electromagnetic wave transmission mode of a portion of the coupled signal light 207 to transform the electromagnetic wave transmission mode of the modulated portion of the coupled signal light 207 into the electromagnetic wave transmission mode of the remaining portion of the coupled signal light 207, thereby enabling the modulated coupled signal light 207 to have a single electromagnetic wave transmission mode.

[0099] For example, such as Figure 3 In some embodiments shown, there are two optical paths between the polarization separation rotator 345 and the beam splitter 341a of the active tunable spectral unit 341. One optical path is used to transmit a portion of the optical signal 308a of one of the transverse electric mode (TE mode) and transverse magnetic mode (TM mode) in the coupled signal light 307, and the other optical path is used to transmit the other converted portion of the optical signal 308b of the transverse electric mode (TE mode) and transverse magnetic mode (TM mode) in the coupled signal light 307. The portion of optical signal 308a and portion of optical signal 308b are combined and coupled in the beam splitter 341a.

[0100] In some embodiments, the detection processing module includes an on-chip interferometric detection optical chip, which includes an active tunable spectral unit and a polarization separation rotator. The active tunable spectral unit and the polarization separation rotator are integrated into the same optical chip, and the optical signal is transmitted through an optical waveguide in the optical chip, effectively improving the device integration.

[0101] like Figure 1In some embodiments shown, the on-chip interference detection optical chip 148 is located in the optical path downstream of the coupler 150, receiving the coupled signal light 107 obtained by the coupler 150. For example... Figure 2 In some of the embodiments shown, the polarization separation rotator 245 and the active tunable spectral unit 241 are integrated into the on-chip interferometric detection optical chip 248, and the detector 242 is located in the optical path downstream of the on-chip interferometric detection optical chip 248.

[0102] In some embodiments, the coupled signal light can be incident on the on-chip interferometric detection optical chip via either grating coupling or end-face coupling. Specifically, as shown below... Figure 3 In some embodiments shown, the coupled signal light 307 is coupled via a grating (e.g.) Figure 3 The coupling grating shown inside the dotted coil 301 is incident on the on-chip interference detection optical chip 348.

[0103] The detector is located in the optical path downstream of the active tunable spectral unit and receives the scanning signal light obtained from the active tunable unit. The detector performs photoelectric conversion on the received scanning signal light to obtain the light intensity of the scanning signal light and generates an electrical signal of light intensity.

[0104] Specifically, such as Figures 1 to 2 In some embodiments shown, detectors 142 / 242 are located in the optical path downstream of the on-chip interferometry detection optical chip 148 / 248 to receive the scanning signal light 109 / 209. For example, as... Figure 3 In some of the embodiments shown, the on-chip interference detection optical chip 148 / 248 and the detector 142 / 242 can be coupled by means of optical fiber connection or waveguide connection.

[0105] It should be noted that, Figures 1 to 3 In some embodiments shown, detectors 142 / 242 are coupled to the interferometric detection optical chip 148 / 248 via optical fiber or waveguide connections. In other embodiments of the invention, the detectors can also be integrated onto the interferometric detection optical chip on-chip.

[0106] It should also be noted that, in some embodiments of the present invention, the signal processing circuit in the solution concentration detection device controls the modulator to scan the phase of the light to be modulated; the signal processing circuit is also configured to control the detector to receive the scan signal light to obtain an electrical signal of light intensity. Specifically, the signal processing circuit is connected to the detector and controls the detector to output an electrical signal of light intensity related to the light intensity of the scan signal light.

[0107] The processing unit is connected to the detector and receives the light intensity electrical signal to obtain the light intensity of the scanning signal light; the processing unit also obtains the phase difference between the signal light to be measured and the reference signal light based on the change in the light intensity of the scanning signal light.

[0108] Specifically, during the phase scanning process of the active tunable spectral unit on the coupled signal light, the actively introduced scanning phase is P. i Based on the principle of interference, the scanning phase is P. i At that time, the intensity I of the scanning signal light received by the detector is... i It can be represented as:

[0109]

[0110] Where I0 is the total incident light intensity.

[0111] When the intensity of the scanning signal light I i The scanning phase P actively introduced by phase scanning i And when the total incident light intensity I0 is known, the phase difference P0 between the signal light to be measured and the reference signal light can be obtained by inversion; where, as Figure 3 In some embodiments shown, the scanning phase P is actively introduced during phase scanning. i This refers to the phase in which the modulator 341b modulates the light to be modulated.

[0112] In some embodiments, the processing unit includes: a fitter configured to obtain a light intensity fitting curve based on changes in the light intensity of the scanning signal light; and a comparator configured to compare the light intensity fitting curve with a pre-stored reference curve to obtain the phase difference between the signal light to be measured and the reference signal light. By fitting the changes in the light intensity of the scanning signal light and comparing the light intensity fitting curve with the reference curve, the influence of the incident light signal intensity on the obtained phase difference can be eliminated, effectively improving the accuracy and reliability of the obtained phase difference.

[0113] like Figure 4 As shown, the fitter 343a of the processing unit 343 is connected to the detector 342 and receives the light intensity I of the scanning signal light obtained by the detector 342. i Specifically, the fitter 343a obtains all scan phases P. i The corresponding scanning signal light intensity I i This allows us to obtain the change in the intensity of the scanning signal light during the phase scanning process; the fitter 343a fits the change in the intensity of the scanning signal light to obtain the intensity fitting curve.

[0114] For example, the fitter 343a responds to changes in the intensity of the scanned signal light (e.g.) Figure 5 The gray scattered points shown in the image are fitted using a nonlinear least squares method, such as cosine fitting, to obtain the light intensity fitting curve (e.g., gray scattered points). Figure 5 The fitted curve is shown by the red dashed line in the middle.

[0115] Continue to refer to Figure 4The comparator 343b of the processing unit 343 is connected to the fitter 343a and receives the light intensity fitting curve obtained by the fitter 343a. The comparator 343b also has a reference curve stored in it. The comparator 343b compares the light intensity fitting curve and the reference curve to obtain the phase difference P0 between the signal light to be measured and the reference signal light.

[0116] Specifically, such as Figure 5 In some embodiments shown, the horizontal axis represents the phase in radians (rad); the vertical axis represents the intensity of the scanning signal light obtained by the detector in arbitrary units (au). The phase difference P0 between the measured signal light and the reference signal light is determined based on the difference between the horizontal coordinates of the corresponding troughs in the intensity fitting curve and the reference curve.

[0117] The calculation unit is connected to the processing unit and receives the phase difference P0 between the test signal light and the reference signal light obtained by the processing unit. The calculation unit also calculates the concentration of the test solution based on the phase difference P0 and the concentration of the reference solution.

[0118] During the transmission of optical signals through a solution, the solution concentration affects the refractive index, thus influencing the optical path length of the signal. After the detection light and reference light are transmitted through the test solution and reference solution respectively, the change in the phase difference between the resulting signal light and the reference light reflects the difference in the optical path length between the detection light in the test solution and the reference light in the reference solution, thereby reflecting the difference in concentration between the test solution and the reference solution.

[0119] On the other hand, both the detection light that forms the test signal light and the reference light that forms the reference signal light are separated from the initial light, and there is no phase difference between the detection light and the reference light, that is, the phase difference between the detection light and the reference light is 0. Therefore, the calculation unit can obtain the concentration of the test solution based on the phase difference P0 between the test signal light and the reference signal light, combined with the concentration of the reference solution.

[0120] The optical path length of a light signal propagating in a solution depends on the optical path length of the light signal in the solution and the refractive index of the solution. Specifically, the optical path length of the detection light propagating in the test solution depends on the length of the optical path to be measured and the refractive index of the test solution; the optical path length of the reference light propagating in the reference solution depends on the length of the reference optical path and the refractive index of the reference solution. Here, the length of the optical path to be measured is the length of the optical path through which the detection light propagates in the test solution, i.e., the geometric length of the path of the detection light propagating in the test solution; the length of the reference optical path is the length of the optical path through which the reference light propagates in the reference solution, i.e., the geometric length of the path of the reference light propagating in the reference solution.

[0121] like Figures 1 to 3In some embodiments shown, the detection light passes through the test solution cavity along its length, and the reference light passes through the reference solution cavity along its length. Both the test solution cavity and the reference solution cavity have a length dimension of L. The initial light wavelength is λ. The refractive index of the test solution is n. test The refractive index of the reference solution is n. ref The refractive index difference Δn between the test solution and the reference solution is: Δn = n test -n ref Since the test solution and reference solution are transmitted separately, the phase difference P0 introduced between the test signal light and the reference signal light can be expressed as:

[0122]

[0123] like Figure 2 In some embodiments shown, the calculation unit 244 pre-stores the dimensions L along the length of the test solution container and the reference solution container, as well as the concentration C of the reference solution. ref and the refractive index-concentration coefficient (d) of the solution to be tested n / d c The phase difference P0 between the test signal light and the reference signal light, combined with the length dimensions L of the test solution cavity and the reference solution cavity, and the concentration C of the reference solution, are used to determine the optimal signal. ref and the refractive index-concentration coefficient (d) of the solution to be tested n / d c ), to obtain the concentration C of the solution to be tested. test .

[0124] In some embodiments, the computing unit includes: a first inverter configured to obtain the refractive index difference between the test solution and a reference solution based on the phase difference; and a second inverter pre-stored with a refractive index-concentration coefficient, configured to obtain the concentration of the test solution based on the refractive index difference, combined with the refractive index-concentration coefficient and the concentration of the reference solution.

[0125] like Figure 4 In some embodiments shown, in the calculation unit 344, the first inverter 344a is connected to the comparator 343b in the processing unit 343, receives the phase difference P0 between the test signal light and the reference signal light obtained by the comparator 343b, and obtains the refractive index difference between the test solution and the reference solution based on the phase difference.

[0126] In some embodiments, the first inverter pre-stores the length of the optical path to be measured and the length of the reference optical path; the first inverter obtains the refractive index difference between the solution to be measured and the reference solution based on the phase difference and in combination with the length of the optical path to be measured and the length of the reference optical path.

[0127] Specifically, the first inverter 344a, based on the phase difference P0, combined with the dimensions L along the length direction of the test solution cavity and the reference solution cavity, and the wavelength λ of the initial light, obtains the refractive index difference Δn between the test solution and the reference solution. The refractive index difference Δn is expressed as:

[0128]

[0129] Continue to refer to Figure 4 In the calculation unit 344, the second inverter 344b is connected to the first inverter 344a and receives the refractive index difference Δn between the test solution and the reference solution obtained by the first inverter 344a; the second inverter 344b has the concentration C of the reference solution pre-stored in it. ref and the refractive index-concentration coefficient (d) of the solution to be tested n / d c The second inverter 344b, based on the refractive index difference Δn and the concentration C of the reference solution, ref and the refractive index-concentration coefficient (d) of the solution to be tested n / d c ), to obtain the concentration C of the solution to be tested. test .

[0130] For example, the concentration C of the test solution obtained by the second inverter 344b test Represented as:

[0131]

[0132] It should be noted that the refractive index-concentration coefficient of a solution refers to the change in the refractive index of the solution caused by a unit change in solute concentration, and its value reflects the sensitivity of the solute to the control of the solution's refractive index.

[0133] Continue to refer to Figure 1 In some embodiments of the present invention, the solution concentration detection device further includes: a circuit chip 147 in the detection processing module 140 connected to the detector 142. For example... Figure 2 As shown, in some embodiments, the circuit chip 247 includes a processing unit 243 and a computing unit 244.

[0134] In some embodiments, the circuit chip further includes a control unit configured to control the active tunable spectral unit to perform phase scanning of the coupled signal light. Specifically, as shown... Figure 2 In some embodiments shown, the control unit 249 in the circuit chip 247 is connected to the active tunable spectral unit 241. The control unit 249 includes a signal processing circuit that generates a scanning signal to control the tuning of the phase of the modulator to be modulated.

[0135] In some embodiments, the control unit is also configured to control the light source to generate initial light. Specifically, such as Figure 2 In some of the embodiments shown, the control unit 249 in the circuit chip 247 is connected to the light source 210 to control the light source to generate initial light.

[0136] It should be noted that, as Figure 1 In some of the embodiments shown, circuit chip 147 is connected to laser 111 in light source 110 to control laser 111 to generate raw light.

[0137] It should be noted that, in the foregoing embodiments, the active tunable spectral unit includes a Mach-Zehnder interferometer structure. In other embodiments of the present invention, the active tunable spectral unit may further include a microring resonator.

[0138] like Figure 6 In some embodiments shown, the active tunable spectral unit 441 is located in the optical path upstream of the detector 442. The active tunable spectral unit 441 includes a microring resonator structure. The microring resonator structure is located in the optical path between the beam splitter 441a and the beam combiner 441c. The microring resonator structure includes a linear optical path 441d for transmitting local oscillator light and a ring optical path 441e for transmitting light to be modulated, wherein the modulator 441b is located in the ring optical path 441e. The beam splitter 441a splits the coupled signal light 407 into local oscillator light transmitted to the linear optical path 441d and light to be modulated transmitted to the ring optical path 441e. The local oscillator light is directly transmitted to the beam combiner 441c via the linear optical path 441d. When the light to be modulated is transmitted in the ring optical path 441e, the modulator 441b located in the ring optical path 441e modulates the phase of the light to be modulated, forming modulated light transmitted to the beam combiner 441c. The beam combiner 441c receives and couples the local oscillator light and the modulated light to form the scanning signal light 409.

[0139] It should be noted that in the structure of the microring resonator, at least one of the linear optical path and the ring optical path can be realized by an on-chip waveguide.

[0140] In addition, such as Figure 6 In some embodiments shown, the coupled signal light 407 is coupled via end-face coupling (e.g., Figure 6 The light cone structure shown in the middle dotted coil 401 is incident on the on-chip interference detection light chip 448.

[0141] In some embodiments, the active tunable spectral unit further includes: a mode separator configured to separate different electromagnetic wave transmission modes in the coupled signal light to obtain a first beam splitter and a second beam splitter; a mode modulator configured to modulate the electromagnetic wave transmission mode of at least one of the first beam splitter and the second beam splitter so that the modulated beam splitter has the same electromagnetic wave transmission mode, and the beam splitter is at least one of the first beam splitter and the second beam splitter; and a beam splitter further configured to couple the modulated beam splitter to obtain the modulated coupled signal light.

[0142] like Figure 6 In some embodiments shown, in the active tunable spectral unit 441, there is a first optical path and a second optical path between the mode splitter 445a and the mode modulator 445b. The mode splitter 445a receives the coupled signal light 407 and splits the coupled signal light 407 into a first split (e.g., ...). Figure 6 (as shown by one of the dashed arrow and dotted arrow) and the second beam splitter (as shown by...) Figure 6 (The other one is shown in the dashed arrow and dotted arrow). The first beam splitter and the second beam splitter are transmitted through the first optical path and the second optical path, respectively. The mode modulator 445b receives the first beam splitter and the second beam splitter, and modulates the electromagnetic wave transmission mode of at least one of the first beam splitter and the second beam splitter, so that the modulated first beam splitter and the second beam splitter have the same electromagnetic wave transmission mode. The beam splitter 441a receives and couples the modulated first beam splitter and the second beam splitter to obtain the modulated coupled signal light.

[0143] For example, in the first and second beams split from the coupled signal light 407 by mode splitter 445a, one beam has an electromagnetic wave transmission mode of transverse electric mode, and the other beam has an electromagnetic wave transmission mode of transverse magnetic mode. Mode modulator 445b deflects the transverse magnetic mode beam by 90° to convert it to transverse electric mode, thereby unifying the electromagnetic wave transmission modes of the first and second beams to transverse electric mode. Beam splitter 441a receives and couples the electromagnetic wave transmission mode of the coupled signal light obtained from the first and second beams to a single transverse electric mode.

[0144] Accordingly, the present invention also provides a method for detecting solution concentration.

[0145] It should be noted that, in some embodiments of the present invention, the solution concentration detection method can be performed using the solution concentration detection device of the present invention. The specific technical solution of the solution concentration detection method can be found in the foregoing. Figures 1 to 6 An example of a solution concentration detection device is shown.

[0146] refer to Figure 7 The diagram shows a flow chart of a solution concentration detection method consistent with some embodiments of the present invention.

[0147] The solution concentration detection method includes: first, performing step S110 to generate initial light.

[0148] Specifically, refer to the following: Figure 1 In step S110, which generates initial light, initial light 102 is generated by light source 110.

[0149] In some embodiments of the present invention, step S110, which generates initial light, includes generating linearly polarized initial light. Specifically, the initial light generated by the light source is linearly polarized light.

[0150] In some embodiments, such as Figure 8 As shown, the step of generating initial light by executing step S110 includes: step S111, generating original light; step S112, converting the original light into linearly polarized initial light.

[0151] Specifically, refer to the following: Figure 1 In step S111, the step of generating the original light 101, the original light 101 can be generated by one of the laser 111 and the LED. The original light 101 can be natural light. In step S112, the step of converting the original light 101 into linearly polarized initial light 102, the original light 101 can be polarized by the polarizer 112, so that the original light 101 is converted into linearly polarized initial light 102.

[0152] Then, step S120 is performed to divide the initial light into detection light and reference light.

[0153] Specifically, refer to the following: Figure 1 In step S120, the initial light 102 is divided into detection light 103 and reference light 104 by a beam splitter 120.

[0154] Continue to refer to Figure 7 The solution concentration detection method further includes: step S130, where the detection light is incident on the solution to be tested and transmitted through the solution to be tested to form a signal light to be tested; and step S140, where the reference light is incident on the reference solution and transmitted through the reference solution to form a reference signal light.

[0155] Specifically, the test solution and the reference solution can be static solutions. The test solution and the reference solution can be statically held in a fluid cell. In other embodiments of the present invention, the test solution and the reference solution can be transported in their respective flow channels in a bubble-free, continuous flow manner; that is, the test solution and the reference solution are stably transported in their respective flow channels without bubble entrainment, retention, or precipitation, and the flow process is continuous.

[0156] It should be noted that the reference solution is a standard solution of known concentration. For example, the reference solution is pure water or a standard buffer solution.

[0157] In some embodiments of the present invention, the solution concentration detection method further includes step S101, placing the test solution and the reference solution in the same physical environment. By placing the test solution and the reference solution in the same physical environment during the detection process, the influence of environmental factors (such as temperature, pressure, vacuum, electromagnetic field, etc.) on the test solution and the reference solution becomes common, effectively improving the stability of the detection results.

[0158] It should be noted that placing the test solution and the reference solution in the same physical environment means that the test solution and the reference solution are located in the same chamber, sharing the same chamber shell, and there is no structural design for heat insulation, pressure isolation or electromagnetic field shielding between the test solution and the reference solution, ensuring that the test solution and the reference solution are in completely identical spatial areas.

[0159] Specifically, refer to the following: Figure 1 The detection light 103 is transmitted through the test solution to form the test signal light 105; the reference light 104 is transmitted through the reference solution to form the reference signal light 106. For example, the detection light 103 is transmitted through the test solution to form the test signal light 105. The reference light 104 is transmitted through the reference solution to form the reference signal light 106.

[0160] Continue to refer to Figure 7 The solution concentration detection method further includes: performing step S150 to obtain the phase difference between the signal light to be tested and the reference signal light.

[0161] By introducing a reference solution of known concentration as a control path and comparing it with the solution to be tested, the concentration of the solution to be tested can be inverted by the phase difference between the signal light to be tested and the reference signal light, which can effectively improve the accuracy of solution concentration detection results.

[0162] In some embodiments of the present invention, the test solution and the reference solution are placed in the same physical environment; the solution concentration detection method further includes: step S130, generating the test signal light; and step S140, after generating the reference signal light, before executing step S150, obtaining the phase difference between the test signal light and the reference signal light, executing step S170, coupling the test signal light and the reference signal light to form a coupled signal light; step S150, obtaining the phase difference between the test signal light and the reference signal light, includes: obtaining the phase difference between the test signal light and the reference signal light based on the coupled signal light. Coupling the test signal light and the reference signal light to form a coupled signal light, and determining the phase difference based on the coupled signal light, can cancel out the common-mode effects on the test signal light and the reference signal light, effectively improving detection accuracy and the stability of detection results.

[0163] Specifically, refer to the following: Figure 1 In step 170, the coupler 105 and the reference signal light 106 are coupled to form the coupled signal light 107.

[0164] In some embodiments, in step 170, the coupling of the test signal light and the reference signal light to form a coupled signal light is performed while maintaining polarization. The polarization state of the signal light is not changed during the coupling of the test signal light and the reference signal light to form the coupled signal light. Both the test signal light and the reference signal light are linearly polarized, and the coupled signal light is also linearly polarized. Using linearly polarized light to detect the reference solution and the test solution, forming linearly polarized test signal light and reference signal light, can effectively improve the coupling efficiency of forming the coupled signal light, effectively improve the signal-to-noise ratio, and contribute to improved detection accuracy and stability.

[0165] In some embodiments, step S150, which involves obtaining the phase difference between the test signal light and the reference signal light based on the coupled signal light, includes: step S151, performing a phase scan on the coupled signal light to obtain a scan signal light; step S152, receiving the scan signal light to obtain its intensity; and step S153, obtaining the phase difference between the test signal light and the reference signal light based on changes in the intensity of the scan signal light. Performing a phase scan on the coupled signal light to form a scan signal light, and then receiving the scan signal light to obtain its intensity, allows for the determination of the phase difference, thereby determining the solution concentration. This approach ensures both the sensitivity and accuracy of solution concentration detection and improves the signal-to-noise ratio, which is beneficial for improving the accuracy and stability of concentration detection results.

[0166] Specifically, refer to the following: Figure 2 In step S151, the coupled signal light 207 is phase-scanned to obtain the scanning signal light 209. In step S152, the scanning signal light 209 is received by the detector 242 to obtain the intensity of the scanning signal light 209 and generate an electrical signal of light intensity.

[0167] In some embodiments, step S151, which involves performing a phase scan on the coupled signal light to obtain a scanned signal light, includes: step S151a, dividing the coupled signal light into a local oscillator light and a light to be modulated; step S151b, modulating the phase of the light to be modulated to obtain a modulated light; and step S151c, coupling the modulated light and the local oscillator light to obtain the scanned signal light.

[0168] Specifically, refer to the following: Figure 3 In the step of performing phase scanning on the coupled signal light 307 to obtain the scanning signal light 309, the coupled signal light 307 is split into a local oscillator light that is transmitted to the first optical path 341d and a light to be modulated that is transmitted to the second optical path 341e by a beam splitter 341a; the local oscillator light is directly transmitted to the beam combiner 341c via the first optical path 341d; when the light to be modulated is transmitted in the second optical path 341e, the phase of the light to be modulated is modulated by the modulator 341b in the second optical path 341e to form the modulated light transmitted to the beam combiner 341c; the beam combiner 341c receives and couples the local oscillator light and the modulated light to form the scanning signal light 309.

[0169] It should be noted that step S151, the step of performing phase scanning on the coupled signal light to obtain the scanning signal light, further includes: generating a scanning signal to control the modulator to tune the phase of the light to be modulated. For example, the step of generating a scanning signal to control the modulator to tune the phase of the light to be modulated includes: generating a scanning signal to control the modulator to perform a linear or stepped scanning of the phase of the light to be modulated, thereby causing the formed modulated light to have a phase delay of 0 to 2π.

[0170] In some embodiments, step S151, the step of phase scanning the coupled signal light to obtain the scanned signal light, includes: before performing step S151a, which divides the coupled signal light into a local oscillator light and a light to be modulated, performing step S151d, which modulates the coupled signal light so that the modulated coupled signal light has a single electromagnetic wave mode; the step of performing step S151a, which divides the coupled signal light into a local oscillator light and a light to be modulated, includes: dividing the modulated coupled signal light into a local oscillator light and a light to be modulated. This ensures that the coupled signal light has a single electromagnetic wave transmission mode, so that the local oscillator light and the light to be modulated formed during the phase scanning process have the same electromagnetic wave transmission mode. This effectively improves the coupling efficiency of the local oscillator light and the modulated light, thereby effectively improving the signal-to-noise ratio and contributing to the improvement of the accuracy and stability of the concentration detection results.

[0171] In some embodiments, step S151d, modulating the coupled signal light to give it a single electromagnetic wave mode, includes: step S151d1, separating different electromagnetic wave modes in the coupled signal light to obtain a first beam splitter and a second beam splitter; step S151d2, modulating the electromagnetic wave mode of at least one of the first beam splitter and the second beam splitter to give the modulated beam splitter the same electromagnetic wave mode, wherein the beam splitter is at least one of the first beam splitter and the second beam splitter; and step S151d3, coupling the modulated beam splitter to obtain the modulated coupled signal light.

[0172] Specifically, refer to the following: Figure 2 In the step of performing phase scanning on the coupled signal light 207 to obtain the scanning signal light 209, the coupled signal light can be modulated by the polarization beam splitter rotator 245 so that the modulated coupled signal light has a single electromagnetic wave mode. The polarization beam splitter rotator (PBSR) can simultaneously perform the functions of "polarization separation" and "polarization rotation", and can separate the incident orthogonal polarization state (TE / TM) and rotate the target polarization state (e.g., TM) into the working polarization state (TE) before beam splitting and outputting.

[0173] Specifically, in step S151, the coupled signal light is phase-scanned to obtain the scanning signal light, and the actively introduced scanning phase is P. i Based on the principle of interference, the scanning phase is P. i At that time, the intensity I of the scanning signal light received by the detector is... i It can be represented as:

[0174]

[0175] Where I0 is the total incident light intensity.

[0176] When the intensity of the scanning signal light I i The scanning phase P actively introduced by phase scanning i And when the total incident light intensity I0 is known, the phase difference P0 between the signal light to be measured and the reference signal light can be obtained by inversion; where, as Figure 3 In some embodiments shown, the scanning phase P is actively introduced during phase scanning. i That is, in step S151b, the phase of the light to be modulated is modulated to obtain the modulated light.

[0177] In some embodiments, such as Figure 12As shown, step S153, the step of obtaining the phase difference between the signal light to be tested and the reference signal light, includes: step S153a, obtaining a light intensity fitting curve based on the change in the light intensity of the scanning signal light; step S153b, comparing the light intensity fitting curve with a pre-stored reference curve to obtain the phase difference between the signal light to be tested and the reference signal light. By fitting the change in the light intensity of the scanning signal light and comparing the light intensity fitting curve with the reference curve, the influence of the incident light signal intensity on the obtained phase difference can be eliminated, which can effectively improve the accuracy and reliability of the obtained phase difference.

[0178] Specifically, refer to the following: Figure 4 In step S153a, the step of obtaining the light intensity fitting curve based on the change in light intensity of the scanning signal light can be achieved by fitting the light intensity fitting curve based on the change in light intensity of the scanning signal light using fitting device 343a; in step S153b, the step of obtaining the phase difference between the signal light to be tested and the reference signal light by comparing the light intensity fitting curve and the pre-stored reference curve can be achieved by comparing the light intensity fitting curve and the pre-stored reference curve using comparator 343b to obtain the phase difference P0 between the signal light to be tested and the reference signal light.

[0179] For example, step S153a, the step of obtaining the light intensity fitting curve based on the change in the light intensity of the scanning signal light, includes: adjusting the light intensity of the scanning signal light (e.g., ... Figure 5 The gray scattered points shown in the image are fitted using a nonlinear least squares method, such as cosine fitting, to obtain the light intensity fitting curve (e.g., gray scattered points). Figure 5 The fitted curve is shown by the red dashed line in the middle.

[0180] Specifically, refer to the following: Figure 5 The horizontal axis represents the phase, with units of radians (rad); the vertical axis represents the light intensity of the scanning signal light obtained by the detector, with units of arbitrary units (au). The phase difference P0 between the measured signal light and the reference signal light is determined based on the difference between the horizontal coordinates corresponding to the peaks or troughs in the light intensity fitting curve and the reference curve.

[0181] Continue to refer to Figure 7 After obtaining the phase difference, step S160 is executed, in which the concentration of the test solution is obtained based on the phase difference P0 and the concentration of the reference solution.

[0182] During the transmission of optical signals through a solution, the solution concentration affects the refractive index, thus influencing the optical path length of the signal. After the detection light and reference light are transmitted through the test solution and reference solution respectively, the change in the phase difference between the resulting signal light and the reference light reflects the difference in the optical path length between the detection light in the test solution and the reference light in the reference solution, thereby reflecting the difference in concentration between the test solution and the reference solution.

[0183] On the other hand, both the detection light that forms the test signal light and the reference light that forms the reference signal light are separated from the initial light, and there is no phase difference between the detection light and the reference light, that is, the phase difference between the detection light and the reference light is 0. Therefore, in step S160, the step of obtaining the concentration of the test solution based on the phase difference P0 and the concentration of the reference solution, the concentration of the test solution can be obtained based on the phase difference P0 between the test signal light and the reference signal light and the concentration of the reference solution.

[0184] The optical path length of a light signal propagating in a solution depends on the optical path length of the light signal in the solution and the refractive index of the solution. Specifically, the optical path length of the detection light propagating in the test solution depends on the length of the optical path to be measured and the refractive index of the test solution; the optical path length of the reference light propagating in the reference solution depends on the length of the reference optical path and the refractive index of the reference solution. Here, the length of the optical path to be measured is the length of the optical path through which the detection light propagates in the test solution, i.e., the geometric length of the path of the detection light propagating in the test solution; the length of the reference optical path is the length of the optical path through which the reference light propagates in the reference solution, i.e., the geometric length of the path of the reference light propagating in the reference solution.

[0185] The optical path lengths of the detection light transmitted through the test solution and the reference light transmitted through the reference solution are both L. The wavelength of the initial light is λ. The refractive index of the test solution is n. test The refractive index of the reference solution is n. ref The refractive index difference Δn between the test solution and the reference solution is: Δn = n test -n ref Since the test solution and reference solution are transmitted separately, the phase difference P0 introduced between the test signal light and the reference signal light can be expressed as:

[0186]

[0187] In step S160, the step of obtaining the concentration of the test solution based on the phase difference P0 and the concentration of the reference solution involves using the phase difference P0 between the test signal light and the reference signal light, combined with the fact that the optical path lengths of the detection light and the reference light transmitting through the test solution are both L, and the concentration C of the reference solution is... ref and the refractive index-concentration coefficient (d) of the solution to be tested n / dc ), to obtain the concentration C of the solution to be tested. test .

[0188] In some embodiments of the present invention, such as Figure 13 As shown, step S160, which involves obtaining the concentration of the solution to be tested based on the phase difference and the concentration of the reference solution, includes: step S161, obtaining the refractive index difference between the solution to be tested and the reference solution based on the phase difference; and step S162, obtaining the concentration of the solution to be tested based on the refractive index difference, a preset refractive index-concentration coefficient, and the concentration of the reference solution.

[0189] In some embodiments, step S161, which involves obtaining the refractive index difference between the solution to be tested and the reference solution based on the phase difference, includes: obtaining the refractive index difference between the solution to be tested and the reference solution based on the phase difference, combined with the length of the optical path to be tested and the length of the reference optical path.

[0190] Specifically, in step S161, the step of obtaining the refractive index difference between the test solution and the reference solution based on the phase difference, the refractive index difference Δn between the test solution and the reference solution is obtained based on the phase difference P0, combined with the dimensions L along the length direction of the test solution cavity and the reference solution cavity, and the wavelength λ of the initial light. The refractive index difference Δn is expressed as:

[0191]

[0192] In step S162, the step of obtaining the concentration of the solution to be tested based on the refractive index difference, combined with a preset refractive index-concentration coefficient and the concentration of the reference solution, involves using the refractive index difference Δn and the concentration C of the reference solution. ref and the refractive index-concentration coefficient (d) of the solution to be tested n / d c ), to obtain the concentration C of the solution to be tested. test .

[0193] For example, in step S162, the concentration C of the test solution is obtained based on the refractive index difference, combined with a preset refractive index-concentration coefficient and the concentration of the reference solution. test Represented as:

[0194]

[0195] It should be noted that the refractive index-concentration coefficient of a solution refers to the change in the refractive index of the solution caused by a unit change in solute concentration, and its value reflects the sensitivity of the solute to the control of the solution's refractive index.

[0196] In summary, by introducing a reference solution of known concentration as a control path and comparing it with the solution to be tested, the concentration of the solution to be tested can be inverted through the phase difference between the signal light to be tested and the reference signal light, which can effectively improve the accuracy of solution concentration detection results.

[0197] Moreover, by placing the test solution and the reference solution in the same physical environment, the influence of the environment on the test solution and the reference solution becomes common mode, which can effectively improve the stability of the detection results.

[0198] Furthermore, by coupling the signal light under test and the reference signal light, the common-mode effects on the two signal lights can be canceled, which can effectively improve the detection accuracy and the stability of the detection results.

[0199] In addition, using linearly polarized light to detect the reference solution and the test solution can effectively improve the coupling efficiency of the generated coupling signal light, effectively improve the signal-to-noise ratio, and help improve detection accuracy and stability.

[0200] In addition, determining the phase difference through phase scanning, and then determining the solution concentration, can not only ensure the sensitivity and accuracy of solution concentration detection, but also improve the signal-to-noise ratio, which is beneficial to improving the accuracy and stability of concentration detection results.

[0201] In addition, by giving the modulated coupled signal light a single electromagnetic wave transmission mode, the local oscillator light and the light to be modulated have the same electromagnetic wave transmission mode, thereby improving the coupling efficiency between the local oscillator light and the modulated light, which can effectively improve the signal-to-noise ratio and is beneficial to improving the accuracy and stability of concentration detection results.

[0202] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A solution concentration detection device, characterized in that, include: A light source, configured to generate initial light; A beam splitter configured to split the initial light into a detection beam and a reference beam; A dual-channel containment chamber includes a test solution containment chamber and a reference solution containment chamber, wherein the test solution containment chamber is configured to contain the test solution and the reference solution containment chamber is configured to contain the reference solution. The detection light is incident on the solution to be tested and transmitted through the solution to be tested to form the signal light to be tested; The reference light is incident on the reference solution and transmitted through the reference solution to form a reference signal light; A detection processing module, configured to obtain the phase difference between the signal light to be tested and the reference signal light; The detection and processing module is further configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution; The detection and processing module includes: an active tunable spectral unit configured to perform phase scanning on the coupled signal light to obtain a scanning signal light; a detector configured to receive the scanning signal light to obtain the light intensity of the scanning signal light; a processing unit configured to obtain the phase difference between the test signal light and the reference signal light based on the change in the light intensity of the scanning signal light; and a calculation unit configured to obtain the concentration of the test solution based on the phase difference and the concentration of the reference solution. The active tunable spectral unit includes: a beam splitter configured to split the coupled signal light into a local oscillator light and a light to be modulated; a modulator configured to modulate the phase of the light to be modulated to obtain modulated light; and a beam combiner configured to couple the modulated light and the local oscillator light to obtain scanning signal light. The detection and processing module further includes: a polarization separation rotator, which is configured to modulate the coupled signal light so that the modulated coupled signal light has a single electromagnetic wave transmission mode; and a beam splitter that splits the modulated coupled signal light into the local oscillator light and the light to be modulated. The active tunable spectral unit further includes: a mode separator configured to separate different electromagnetic wave transmission modes in the coupled signal light to obtain a first beam splitter and a second beam splitter; a mode modulator configured to modulate the electromagnetic wave transmission mode of at least one of the first beam splitter and the second beam splitter so that the modulated beam splitter has the same electromagnetic wave transmission mode, wherein the beam splitter is at least one of the first beam splitter and the second beam splitter; and the beam splitter is further configured to couple the modulated beam splitter to obtain the modulated coupled signal light.

2. The solution concentration detection device as described in claim 1, characterized in that, The test solution container and the reference solution container are located in the same physical environment.

3. The solution concentration detection device as described in claim 1 or 2, characterized in that, Also includes: A coupler configured to couple the signal light under test and the reference signal light to form a coupled signal light; The detection and processing module obtains the phase difference between the signal light to be tested and the reference signal light based on the coupled signal light.

4. The solution concentration detection device as described in claim 3, characterized in that, The light source is a linearly polarized light source.

5. The solution concentration detection device as described in claim 4, characterized in that, The light source includes at least one of a laser and an LED; The light source also includes a polarizer, which is located in the optical path between the light source and the beam splitter.

6. The solution concentration detection device as described in claim 1, characterized in that, The active tunable spectral unit includes at least one structure of a microring resonator and a Mach-Zehnder interferometer.

7. The solution concentration detection device as described in claim 1, characterized in that, The modulator includes a thermo-optical phase modulator.

8. The solution concentration detection device as described in claim 1, characterized in that, The detection and processing module includes an on-chip interferometric detection optical chip, which includes the active tunable spectral unit and the polarization separation rotator.

9. The solution concentration detection device as described in claim 1, characterized in that, The processing unit includes: A fitter configured to obtain a light intensity fitting curve based on the change in light intensity of the scanned signal light; A comparator is configured to compare the light intensity fitting curve with a pre-stored reference curve to obtain the phase difference between the signal light under test and the reference signal light.

10. The solution concentration detection device as described in claim 1, characterized in that, The calculation unit of the detection processing module includes: A first inversion unit is configured to obtain the refractive index difference between the test solution and the reference solution based on the phase difference. The second inversion unit has a pre-stored refractive index-concentration coefficient and is configured to obtain the concentration of the test solution based on the refractive index difference, the refractive index-concentration coefficient, and the concentration of the reference solution.

11. The solution concentration detection device as described in claim 10, characterized in that, The first inverter has a pre-stored optical path length to be tested and a reference optical path length, wherein the optical path length to be tested is the optical path length through which the detection light is transmitted from the solution to be tested, and the reference optical path length is the optical path length through which the reference light is transmitted from the reference solution. The first inverter obtains the refractive index difference between the solution to be tested and the reference solution based on the phase difference, combined with the length of the optical path to be tested and the length of the reference optical path.

12. A method for detecting solution concentration, characterized in that, include: Generate initial light; The initial light is divided into detection light and reference light; The detection light is incident on the solution to be tested and transmitted through the solution to be tested to form the signal light to be tested; The reference light is incident on the reference solution and transmitted through the reference solution to form a reference signal light; The phase difference between the signal light to be tested and the reference signal light is obtained; Based on the phase difference and the concentration of the reference solution, the concentration of the test solution is obtained. The step of obtaining the phase difference between the signal light to be tested and the reference signal light based on the coupled signal light includes: performing a phase scan on the coupled signal light to obtain a scan signal light; receiving the scan signal light to obtain the light intensity of the scan signal light; and obtaining the phase difference between the signal light to be tested and the reference signal light based on the change in the light intensity of the scan signal light. The step of performing phase scanning on the coupled signal light to obtain scanning signal light includes: dividing the coupled signal light into a local oscillator light and a light to be modulated; modulating the phase of the light to be modulated to obtain modulated light; and coupling the modulated light and the local oscillator light to obtain scanning signal light. The step of performing phase scanning on the coupled signal light to obtain the scanned signal light further includes: before dividing the coupled signal light into local oscillator light and light to be modulated, modulating the coupled signal light so that the modulated coupled signal light has a single electromagnetic wave transmission mode; the step of dividing the coupled signal light into local oscillator light and light to be modulated includes: dividing the modulated coupled signal light into local oscillator light and light to be modulated; The step of modulating the coupled signal light to give it a single electromagnetic wave transmission mode includes: separating different electromagnetic wave transmission modes in the coupled signal light to obtain a first beam splitter and a second beam splitter; modulating the electromagnetic wave transmission mode of at least one of the first beam splitter and the second beam splitter to give the modulated beam splitter the same electromagnetic wave transmission mode, wherein the beam splitter is at least one of the first beam splitter and the second beam splitter; and coupling the modulated beam splitter to obtain the modulated coupled signal light.

13. The solution concentration detection method as described in claim 12, characterized in that, Also includes: The test solution and the reference solution are placed in the same physical environment.

14. The solution concentration detection method as described in claim 12 or 13, characterized in that, Also includes: Before obtaining the phase difference between the signal light to be tested and the reference signal light, the signal light to be tested and the reference signal light are coupled to form a coupled signal light; The step of obtaining the phase difference between the signal light under test and the reference signal light includes: obtaining the phase difference between the signal light under test and the reference signal light based on the coupled signal light.

15. The solution concentration detection method as described in claim 14, characterized in that, The steps for generating initial light include: generating linearly polarized initial light.

16. The solution concentration detection method as described in claim 15, characterized in that, The steps to generate the initial light include: Generates primordial light; This converts the original light into linearly polarized initial light.

17. The solution concentration detection method as described in claim 12, characterized in that, The step of obtaining the phase difference between the signal light to be tested and the reference signal light includes: Based on the change in the intensity of the scan signal light, an intensity fitting curve is obtained; By comparing the light intensity fitting curve with the pre-stored reference curve, the phase difference between the signal light to be measured and the reference signal light is obtained.

18. The solution concentration detection method as described in claim 12, characterized in that, The step of obtaining the concentration of the test solution based on the phase difference and the concentration of the reference solution includes: Based on the phase difference, the refractive index difference between the solution to be tested and the reference solution is obtained; The concentration of the solution to be tested is obtained based on the refractive index difference, combined with a preset refractive index-concentration coefficient and the concentration of the reference solution.

19. The solution concentration detection method as described in claim 18, characterized in that, The step of obtaining the refractive index difference between the test solution and the reference solution based on the phase difference includes: Based on the phase difference, and in conjunction with the length of the optical path to be measured and the length of the reference optical path, the refractive index difference between the solution to be measured and the reference solution is obtained; Wherein, the optical path length to be tested is the optical path length through which the detection light is transmitted from the solution to be tested, and the optical path length to the reference optical path is the optical path length through which the reference light is transmitted from the reference solution.

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