All-fiber phase detection system and method based on polarization interference quantum weak measurement

Abstract

The invention belongs to the field of quantum precision measurement, and particularly discloses an all-fiber phase detection system and method based on polarization interference quantum weak measurement. The device sequentially comprises a laser light source, a front selection module, a phase regulation and control module, a rear selection module and a photoelectric acquisition module along a light path. The front selection module prepares linearly polarized light emitted by the laser light source into two equal-amplitude superposition states in a cross-polarization mode as initial polarization states, and the phase regulation and control module senses the phase difference after change conversion of a physical quantity to be measured, dissipates the phase difference accumulated by the two polarization states in the sensing transmission process, and adjusts the phase difference of the two polarization states. And the post selection module performs nearly orthogonal projection measurement on the polarization state, in the process, a birefringence phase difference caused by a physical quantity to be measured is converted into a weak-value amplified light intensity signal, and the photoelectric acquisition module obtains the physical quantity to be measured by monitoring the relative variation of the optical power. Based on the quantum weak measurement principle, the birefringence phase difference caused by the to-be-measured physical quantity is converted into the weak value amplified optical power signal, and the sensing sensitivity is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of quantum precision measurement, and more particularly relates to a full-fiber phase detection system and method based on polarization interference quantum weak measurement. BACKGROUND

[0002] Temperature sensing technology is a core means of industrial monitoring, environmental control and scientific research. Fiber-optic temperature sensors have advantages such as anti-electromagnetic interference, corrosion resistance, high sensitivity and distributed measurement, and have great application potential in power systems, petrochemical industry, biological medicine and deep space exploration.

[0003] However, traditional fiber-optic temperature sensors are mostly based on light intensity modulation, fiber Bragg gratings (FBG) or interference structures (such as Mach-Zehnder interferometers) to achieve their principles, which rely on the change of optical path difference or refractive index caused by temperature, and are limited by noise interference and sensitivity bottleneck, making it difficult to meet the demand for high-precision temperature measurement.

[0004] Quantum weak measurement amplifies the weak signal coupling by the non-orthogonality of the pre-selection and post-selection states, and converts the small change of the measured physical quantity (such as phase, refractive index) into a significant shift of the pointer quantity, which can theoretically achieve super-resolution measurement and provide a new way for high-precision sensing. Existing quantum weak measurement systems are composed of discrete optical elements, which have problems such as system complexity, poor stability, insufficient environmental adaptability and high difficulty in integration. SUMMARY

[0005] In view of the defects of the prior art, the purpose of the present application is to provide a full-fiber phase detection system and method based on polarization interference quantum weak measurement, aiming to solve the problem that the prior art cannot balance miniaturization and high-precision sensing characteristics.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a full-fiber phase detection system based on polarization interference quantum weak measurement, comprising: a laser light source for generating stable linearly polarized light; a pre-selection module for preparing the linearly polarized light emitted by the laser light source into an equal-amplitude superposition state of two orthogonal polarization modes as an initial polarization state by a 45° fusion method, and then the light enters a phase control module; a phase control module for sensing the phase difference converted by the change of the measured physical quantity; dissipating the accumulated phase difference of the two polarization states in the sensing transmission process by a 90° fusion method, thereby realizing rough regulation of the polarization state; and finely adjusting the initial phase difference of the dual polarization state of the light signal by a polarization controller, and the light carrying the phase difference converted by the change of the measured physical quantity enters a post-selection module; A post-selection module, configured to project and measure two polarization states approximately orthogonal to each other by a 45° fusion method, and convert a birefringence phase difference caused by a physical quantity to be measured into a weakly amplified light intensity signal in the process; An optoelectronic acquisition module, configured to receive the light signal output by the post-selection module and convert it into an electrical signal, and obtain the physical quantity to be measured by monitoring the relative change in optical power.

[0007] Preferably, the laser light source is a narrow linewidth laser.

[0008] Preferably, the pre-selection module is a first polarization maintaining optical fiber, the phase control module includes a second polarization maintaining optical fiber and a polarization controller, and the post-selection module is a third polarization maintaining optical fiber; wherein, One end of the first polarization maintaining optical fiber is connected to the output optical fiber of the laser light source and an initial polarization state is constructed by a 45° fusion method, and the other end is connected to the second polarization maintaining optical fiber; The other end of the second polarization maintaining optical fiber is connected to the third polarization maintaining optical fiber through the polarization controller and a post-selection state approximately orthogonal to each other is constructed by a 45° fusion method, a 90° fusion is arranged at the midpoint of the two 45° fusions for phase coarse adjustment and dissipation, and a section of the second polarization maintaining optical fiber serves as a sensing optical fiber, which is configured to sense the change of the physical quantity to be measured and linearly convert the physical quantity change into a phase difference through a birefringence effect; The other end of the third polarization maintaining optical fiber is connected to the optoelectronic acquisition module. The polarization controller is configured to change the initial phase difference of the dual polarization state of the light signal input to the post-selection module, and the initial phase difference of the dual polarization state is the sum of the accumulated phase difference of the total polarization maintaining optical fiber and the phase controlled by the polarization controller, and the total polarization maintaining optical fiber includes the first polarization maintaining optical fiber and the second polarization maintaining optical fiber.

[0009] Preferably, the accumulated phase difference of the two polarization states in the sensing transmission process is as follows:

[0010] wherein, is the accumulated phase difference, is the birefringence difference of the polarization maintaining optical fiber, is the length of the sensing optical fiber, is the wavelength of the incident light.

[0011] Preferably, the birefringence coefficient of the second polarization maintaining optical fiber is changed by extruding or rotating the polarization controller, so as to change the initial phase difference of the dual polarization state of the light signal input to the post-selection module.

[0012] Preferably, the polarization maintaining optical fibers are connected by polarization fusion technology using a polarization maintaining optical fiber fusion machine.

[0013] Preferably, the initial polarization state is:

[0014] in, The initial polarization state, and These are the basis vectors for the fast and slow axis polarization states of the polarization-maintaining fiber, respectively.

[0015] Preferably, the formula for calculating the coupling change is as follows:

[0016] in, The change in the physical quantity to be measured is called the coupled change. This is the difference in optical power signals. This is the initial optical power value. To select the phase angle later, To maintain the birefringence difference of the polarization-maintaining fiber, The value represents the change in birefringence difference of the sensing fiber caused by the measurement. To sense the length of the optical fiber, The value represents the change in the length of the sensing fiber caused by the measurement. λ is the wavelength of the incident light.

[0017] Preferably, the physical quantity to be measured is ambient temperature, vibration amplitude, or dynamic stress.

[0018] To achieve the above objectives, in a second aspect, this application provides an all-fiber phase detection method based on polarization interference quantum weak measurement, applied to the system described in the first aspect, wherein the all-fiber phase detection method includes: (1) Record the laser power value Reconnecting system; (2) Adjust the phase modulation module so that the light intensity detected by the photoelectric acquisition module is close to zero but not equal to zero, and use it as the initial light power value. ; (3) At the initial optical power, through After calculation, select the phase angle. Calibrate the coupling quantity sensing sensitivity value ,in, To maintain the birefringence difference of the polarization-maintaining fiber, The value represents the change in birefringence difference of the sensing fiber caused by the measurement. To sense the length of the optical fiber, The value represents the change in the length of the sensing fiber caused by the measurement. The wavelength of the incident light; (4) After the physical quantity to be measured is coupled with the system, the optical power value of the photoelectric acquisition module is collected, and the coupling quantity sensing sensitivity value is combined with the optical power value. Calculate the change in coupling quantity wherein, is the change of the physical quantity to be measured, i.e., the coupling change, is the optical power signal difference.

[0019] It can be understood that the beneficial effects of the above second aspect can be referred to the related description in the above first aspect, which will not be repeated here.

[0020] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects: The present application proposes a polarization interference quantum weak measurement based all-fiber phase detection system, which includes a laser light source, a front selection module, a phase control module, a rear selection module and a photoelectric acquisition module in sequence along an optical path. The front selection module prepares linearly polarized light emitted by the laser light source into an equal-amplitude superposition state of two orthogonal polarization modes as an initial polarization state. The phase control module senses the phase difference converted after the change of the physical quantity to be measured. The phase difference accumulated by the two polarization states in the sensing transmission process is dissipated, so as to realize rough regulation of the polarization state. The rear selection module performs nearly orthogonal projection measurement on the polarization state. In this process, the birefringent phase difference caused by the physical quantity to be measured is converted into a weakly amplified light intensity signal. The photoelectric acquisition module obtains the physical quantity to be measured by monitoring the relative change of the optical power. Based on the principle of quantum weak measurement, the present application converts the birefringent phase difference caused by the physical quantity to be measured into a weakly amplified optical power signal through weak coupling of the front selection state and the rear selection state, thereby improving the sensing sensitivity. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of the polarization interference quantum weak measurement based all-fiber phase detection system provided by the present application.

[0022] Figure 2 is a voltage signal and temperature change relationship diagram provided by the present application.

[0023] Figure 3 is a sensitivity diagram provided by the present application. is contrast experimental data of the sensitivity adjustment provided by the present application.

[0024] Figure 4 is a theoretical sensitivity diagram under different initial light intensities provided by the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0026] The embodiments of the present application will be described below in combination with the drawings in the embodiments of the present application.

[0027] As Figure 1 shown, the application provides a full-fiber phase detection system based on polarization interference quantum weak measurement, which includes a laser light source, a front selection module, a phase control module, a rear selection module and a photoelectric acquisition module in sequence along the optical path.

[0028] The laser light source is used to generate stable linearly polarized light.

[0029] The front selection module is used to prepare the linearly polarized light emitted by the laser light source into an equal-amplitude superposition state of two orthogonal polarization modes as an initial polarization state by a 45° fusion method, and then the light enters the phase control module.

[0030] The phase control module is used to sense the phase difference converted by the change of the physical quantity to be measured; through a 90° fusion method, the phase difference accumulated by the two polarization states in the sensing transmission process is dissipated, so as to realize rough regulation of the polarization state; through fine adjustment of the polarization controller, the initial phase difference of the dual polarization state of the optical signal is changed, and the light carrying the phase difference converted by the change of the physical quantity to be measured enters the rear selection module.

[0031] The rear selection module is used to perform nearly orthogonal projection measurement on the polarization state by a 45° fusion method, and in this process, the birefringent phase difference caused by the physical quantity to be measured is converted into a weak value amplified light intensity signal.

[0032] The photoelectric acquisition module is used to receive the optical signal output by the rear selection module and convert it into an electrical signal, and the physical quantity to be measured is obtained by monitoring the relative change of optical power.

[0033] Preferably, the laser light source is a narrow linewidth laser.

[0034] Preferably, as Figure 1 shown, the front selection module is a first polarization maintaining optical fiber , the phase control module includes a second polarization maintaining optical fiber and a polarization controller, and the rear selection module is a third polarization maintaining optical fiber ; wherein one end of the first polarization maintaining optical fiber is connected with an output optical fiber of the laser light source The initial polarization state is connected and configured by 45° fusion splicing, and the other end is connected with the second polarization maintaining optical fiber; the other end of the second polarization maintaining optical fiber is connected with the third polarization maintaining optical fiber through the polarization controller and is configured by 45° fusion splicing to form a nearly orthogonal post-selection state, a 90° fusion splicing is arranged at the midpoint of the two 45° fusion splicing to perform phase coarse adjustment and dissipation, and a section of the second polarization maintaining optical fiber is used as a sensing optical fiber, the sensing optical fiber is used to perceive the change of the physical quantity to be measured, and the change of the physical quantity is linearly converted into a phase difference through the birefringence effect; the other end of the third polarization maintaining optical fiber is connected to a photoelectric acquisition module; the polarization controller is used to change the initial phase difference of the dual polarization state of the light signal input to the post-selection module, the initial phase difference of the dual polarization state is the sum of the accumulated phase difference of the total polarization maintaining optical fiber and the phase controlled by the polarization controller, and the total polarization maintaining optical fiber includes the first polarization maintaining optical fiber and the second polarization maintaining optical fiber.

[0035] The light path process of the whole system is as follows: the stable linearly polarized light generated by the laser light source enters the pre-selection module composed of 45° fusion splicing polarization maintaining optical fiber first, and is prepared as an equal-amplitude superposition state of two orthogonal polarization modes, that is, a pre-selection state. The light then enters the phase control module, and a section of 90° fusion splicing polarization maintaining optical fiber is used for rough dissipation and resetting of the phase difference, and in this module, a part of the optical fiber is used as a sensing unit to convert the weak change of the external physical quantity to be measured (such as temperature) into a phase difference of light wave; at the same time, a polarization controller is used for fine adjustment and setting of the initial working phase of the system. The light carrying the signal phase then enters the post-selection module, and another section of 45° fusion splicing polarization maintaining optical fiber is used for nearly orthogonal projection measurement of the polarization state, that is, post-selection. In this process, based on the principle of quantum weak measurement, the small signal phase difference is sharply amplified into a significant change of the output light intensity. Finally, the light intensity signal is received by a photodetector (PD) in the photoelectric acquisition module and converted into an electrical signal, thereby realizing high-sensitivity detection of the weak signal.

[0036] The all-fiber phase detection system provided in the application utilizes the polarization interference quantum weak measurement theory in the following way (taking temperature change as an example): Using 45° fusion splicing polarization maintaining optical fiber Converting the light output by the laser light source into an initial polarization state: , wherein, and represent the fast-axis and slow-axis polarization basis vectors of the polarization maintaining optical fiber.

[0037] Temperature change causes the polarization maintaining optical fiber A phase difference is generated between the two orthogonal polarization modes in the coupling part , and the system state after coupling evolution is , wherein, is the quantum state of the system after evolution, is the interaction strength, is the frequency of the instrument pointer, is the observed operator, is the state vector of the optical power meter, is the accumulated phase difference of the two polarization states in the sensing section of the polarization maintaining fiber.

[0038] using another 45°-fused section of polarization maintaining fiber As a post-selection module, the projection measurement of the polarization state is realized, and the final state of the optical power meter is wherein, is the post-selected post-instrument final state, is the post-selected polarization state, is the fiber phase difference, , is the intrinsic phase difference of the system under the initial condition, is the phase difference that changes with temperature. The optical intensity measured by the optical power meter is wherein, is the output power when The change rate of is measured, and the amplified observation of the weak value of the coupling is completed.

[0039] It should be noted that, by strictly controlling the lengths of the 45°-90° and 90°-45° sections to be equal, the accumulated phase difference before fusion is dissipated, so that the polarization state is roughly controlled; the pre-selection and post-selection modules are designed and constructed using all-fiber structure and polarization maintaining fiber, so that the influence of environmental disturbance is reduced.

[0040] Preferably, the accumulated phase difference of the two polarization states in the sensing transmission process is as follows:

[0041] wherein, is the accumulated phase difference, is the birefringence of the polarization maintaining fiber, is the length of the sensing fiber, is the wavelength of the incident light.

[0042] Preferably, by extruding and rotating the polarization controller, the birefringence coefficient of the second polarization maintaining fiber is changed, and then the initial phase difference of the dual polarization state of the optical signal input into the post-selection module is changed.

[0043] It should be noted that the initial phase difference of the dual polarization state is the total accumulated phase difference of the polarization maintaining fiber and the phase controlled by the polarization controller .

[0044] Preferably, the polarization maintaining fibers are connected by polarization fusion technology using a polarization maintaining fiber fusion machine.

[0045] It should be noted that the present application realizes the miniaturization, integration and environmental interference resistance of the system through the full-polarization-maintaining fiber fusion structure, combines the high sensitivity advantage of quantum weak measurement with the practicability of optical fiber sensor, and is especially suitable for high-precision temperature monitoring in narrow space and harsh environment.

[0046] Preferably, the initial polarization state is:

[0047] wherein, is an initial polarization state, and are the base vectors of the polarization states of the fast axis and the slow axis of the polarization-maintaining fiber, respectively.

[0048] Preferably, the calculation formula of the coupling change is as follows:

[0049] wherein, is the change of the physical quantity to be measured, i.e., the coupling change, is the difference of the optical power signals, is the initial optical power value, is the post-selection phase angle, is the birefringence difference of the polarization-maintaining fiber, is the change value of the birefringence difference of the sensing fiber caused by the measured quantity, is the length of the sensing fiber, is the change value of the length of the sensing fiber caused by the measured quantity, is the wavelength of the incident light.

[0050] Preferably, the physical quantity to be measured is the environmental temperature, the vibration amplitude or the dynamic stress.

[0051] If the physical quantity to be measured is the environmental temperature, the sensing fiber can be directly placed in the environment to be measured during measurement. If the physical quantity to be measured is the vibration amplitude, the sensing fiber can be fixed on the vibration source during measurement to ensure the coupling between the measured quantity and the system. If the physical quantity to be measured is the dynamic stress, the sensing fiber can be directly subjected to the measured stress during measurement to ensure the coupling between the measured quantity and the system.

[0052] Preferably, the photoelectric acquisition module includes a PD and an acquisition card, which are used to convert the optical signal into an electrical signal and then save and analyze.

[0053] On the basis of the above, the present application provides a full-fiber phase detection method based on polarization interference quantum weak measurement, which comprises: (1) recording the laser power value and connecting the system; (2) Adjust the phase modulation module so that the light intensity detected by the photoelectric acquisition module is close to zero but not equal to zero, and use it as the initial light power value. ; (3) At the initial optical power, through After calculation, select the phase angle. Calibrate the coupling quantity sensing sensitivity value ,in, To maintain the birefringence difference of the polarization-maintaining fiber, The value represents the change in birefringence difference of the sensing fiber caused by the measurement. To sense the length of the optical fiber, The value represents the change in the length of the sensing fiber caused by the measurement. The wavelength of the incident light; (4) After the physical quantity to be measured is coupled with the system, the optical power value of the photoelectric acquisition module is collected, and the coupling quantity sensing sensitivity value is combined with the optical power value. Calculate the change in coupling quantity ,in, The change in the physical quantity to be measured is called the coupled change. This represents the difference in optical power signals.

[0054] Example In one illustrated embodiment, the physical quantity to be measured is ambient temperature, the laser source is a narrow linewidth laser, and the output wavelength is set to 1550 nm. The wavelength is generated by the polarization-maintaining fiber pre-selection module. The birefringence of polarization-maintaining fiber is... The difference between the thermo-optic coefficients and the difference between the thermal expansion coefficients of the two polarization states are respectively and The phase difference resulting from the change in the birefringence of the temperature-sensing fiber with temperature is: At this point, the polarization controller is adjusted to make the initial light intensity nW, after calculation, select the angle rad, calculated sensitivity is The time-domain variations of its voltage and temperature signals are plotted as follows: Figure 2 The horizontal axis represents the measurement time, the blue vertical axis represents the temperature of the coupling environment, and the red vertical axis represents the acquired output voltage.

[0055] To verify the theoretical model, a method of comparing experimental measurements with simulation was adopted: on the one hand, experiments were conducted using five sets of initial light intensities (318, 365, 401, 494, 537 nW) to obtain the relationship between the relative voltage signal and temperature. Figure 3 The corresponding experimental temperature sensitivity values ​​are -16.56, -15.61, -14.87, -13.35, and -12.90 ( / K). is the initial measured voltage, 34℃ is the initial temperature, and 18℃ is the final temperature.

[0056] On the other hand, the corresponding theoretical change relationship is simulated by simulation Figure 4 , and the corresponding temperature sensitivity calculation values are -16.96, -15.83, -15.10, -13.60, and -13.05 ( / K), respectively. Through comparison, it can be seen that in the five sets of control experiments, the experimental values of the temperature sensitivity are in good agreement with the calculation values, which indicates the correctness of the theoretical model and the feasibility of the all-fiber quantum weak measurement temperature sensing system and the detection method.

[0057] It should be understood that expressions such as "include" and "may include" used in the present application indicate the presence of disclosed functions, operations or constituent elements, and do not limit one or more additional functions, operations and constituent elements. In the present application, terms such as "include" and / or "have" can be interpreted to mean that a specific feature, number, operation, constituent element, component or combination thereof is present, but cannot be interpreted to exclude the presence or addition of one or more other features, numbers, operations, constituent elements, components or combinations thereof.

[0058] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed terms. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0059] In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, "connection" can be detachable connection, or can be non-detachable connection; can be direct connection, or can be indirect connection through an intermediate medium. Among them, "fixed connection" means that the relative positional relationship after connection is unchanged. "Rotary connection" means that the relative rotation after connection is connected. "Sliding connection" means that the relative sliding after connection is connected. The orientation language mentioned in the embodiments of the present application, such as "top", "bottom", "inner", "outer", "left", "right", etc., is only the direction of the drawing, therefore, the orientation language used is to better, more clearly illustrate and understand the embodiments of the present application, and is not to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the embodiments of the present application.

[0060] The terms "first" and "second" and the like in the present application are used to distinguish different objects, rather than to describe a specific order of the objects. For example, the first response message and the second response message are used to distinguish different response messages, rather than to describe a specific order of the response messages.

[0061] In the embodiments of the present application, the word "exemplary" or "for example" is used to mean serving as an example, instance, or illustration. Any implementation or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being superior or inferior, or as having more or less advantages, than other implementation or design solutions. Rather, the use of the word "exemplary" or "for example" is merely intended to present certain concepts in a concrete manner.

[0062] In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified, for example, a plurality of processing units means two or more processing units, and the like; a plurality of elements means two or more elements, and the like.

[0063] The above only describes the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An all-fiber phase detection system based on polarization interference quantum weak measurement, characterized in that, include: Laser light source, used to generate stable linearly polarized light; The pre-selection module is used to prepare the linearly polarized light emitted from the laser source into a superposition state of two orthogonal polarization modes with equal amplitude through a 45° fusion method, which serves as the initial polarization state, and then the light enters the phase modulation module. The phase modulation module is used to sense the phase difference after the change of the measured physical quantity; By using a 90° fusion method, the phase difference accumulated between the two polarization states during the sensing and transmission process is dissipated, thereby achieving coarse control of the polarization state; By finely adjusting the polarization controller, the initial phase difference of the dual polarization state of the optical signal is changed, and the light carrying the phase difference after the change of the measured physical quantity enters the post-selection module. The post-selection module is used to perform near-orthogonal projection measurement of the polarization state through a 45° fusion method. In this process, the birefringence phase difference caused by the physical quantity to be measured is converted into a weakly amplified light intensity signal. The photoelectric acquisition module is used to receive the optical signal output by the post-selection module and convert it into an electrical signal. The physical quantity to be measured is obtained by monitoring the relative change in optical power.

2. An all-fiber phase detection system as claimed in claim 1, wherein, The laser source is a narrow linewidth laser.

3. An all-fiber phase detection system as in claim 1, wherein, The front selection module is a first polarization-maintaining fiber, the phase modulation module includes a second polarization-maintaining fiber and a polarization controller, and the rear selection module is a third polarization-maintaining fiber; wherein... One end of the first polarization-maintaining fiber is connected to the output fiber of the laser source and the initial polarization state is constructed by 45° fusion splicing, while the other end is connected to the second polarization-maintaining fiber. The other end of the second polarization-maintaining fiber passes through the polarization controller and is connected to the third polarization-maintaining fiber. A nearly orthogonal post-selection state is constructed by a 45° fusion splice. A 90° fusion splice is set at the midpoint of the two 45° fusion splices for phase coarse adjustment and dissipation. A section of the second polarization-maintaining fiber is used as a sensing fiber. The sensing fiber is used to sense the change of the physical quantity to be measured and linearly converts the change of the physical quantity into a phase difference through the birefringence effect. The other end of the third polarization-maintaining fiber is connected to the photoelectric acquisition module; The polarization controller is used to change the initial phase difference of the dual polarization state of the optical signal input to the post-selection module. The initial phase difference of the dual polarization state is the sum of the phase difference accumulated by the total polarization-maintaining fiber and the phase controlled by the polarization controller. The total polarization-maintaining fiber includes a first polarization-maintaining fiber and a second polarization-maintaining fiber.

4. An all-fiber phase detection system as in claim 3, wherein, The phase difference accumulated between the two polarization states during the sensing and transmission process is as follows: wherein, is the phase difference accumulated, is the birefringence difference of the polarization maintaining optical fiber, is the length of the sensing optical fiber, is the wavelength of the incident light.

5. An all-fiber phase detection system as in claim 3, wherein, By squeezing and rotating the polarization controller, the birefringence coefficient of the second polarization-maintaining fiber is changed, thereby altering the initial phase difference of the dual polarization state of the optical signal input to the post-selection module.

6. An all-fiber phase detection system as in claim 3, wherein, All polarization-maintaining optical fibers are connected using a polarization-maintaining optical fiber fusion splicer and polarization fusion splicing technology.

7. An all-fiber phase detection system as in claim 1, wherein, The initial polarization state is: wherein, is the initial polarization state, and are the base vectors of the polarization states of the fast and slow axes of the polarization maintaining fiber, respectively.

8. An all-fiber phase detection system as in claim 1, wherein, The formula for calculating the coupling change is as follows: wherein, is a change value of the physical quantity to be measured, i.e. a coupling change value, is a light power signal difference value, is an initial light power value, is a post-selection phase angle, is a birefringence difference of the polarization maintaining optical fiber, is a change value of the birefringence difference of the sensing optical fiber caused by the quantity to be measured, is a length of the sensing optical fiber, is a change value of the length of the sensing optical fiber caused by the quantity to be measured, is an incident light wavelength.

9. An all-fiber phase detection system as claimed in any of claims 1 to 8, characterized in that, The physical quantity to be measured is ambient temperature, vibration amplitude, or dynamic stress.

10. An all-fiber phase detection method based on polarization interference quantum weak measurement, characterized in that, Applied to the system as described in any one of claims 1 to 9, the all-fiber phase detection method comprises: (1) record the laser power value rear connection system; (2) Adjusting the phase control module, so that the light intensity detected by the photoelectric collection module is close to zero but not equal to zero, as the initial light power value ; (3) under the initial optical power, the phase angle is calculated by , and the coupling quantity sensing sensitivity value is calibrated, wherein is the birefringence difference of the polarization maintaining optical fiber, is the change value of the sensing optical fiber birefringence difference caused by the to-be-measured quantity, is the length of the sensing optical fiber, is the change value of the sensing optical fiber length caused by the to-be-measured quantity, is the wavelength of the incident light; (4) After the to-be-measured physical quantity is coupled with the system, the optical power value of the photoelectric collection module is collected, and the coupling quantity sensing sensitivity value is combined to calculate the coupling quantity change value , wherein , is the change value of the to-be-measured physical quantity, that is, the coupling change value, is the optical power signal difference value.

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