Multiple range measuring device and method for fiber optic device characteristics

Abstract

The present application relates to the field of optical testing and calibration technology, and more particularly to a kind of multiple range measurement device and method of optical fiber device characteristics, to be measured object accesses measurement access detection module, forms circulating test optical path;Low coherence demodulation detection module generates reference light and test light, reference light returns after being scanned by reflection dynamic scanning module spatial optical path, test light enters measurement access detection module after being scanned by the module, and multiple range circulating transmission is completed with to-be-measured object, and the output of test light after transmission returns low coherence demodulation detection module after being scanned by the module again;The module interferes with the received reference light and test light, and obtains measurement result.The present application is tested by multiple range optical fiber ring test structure, integrates commonly used optical fiber and device characteristics, perfects access mode, cooperates calibration correction model, realizes multiple types, multiple parameters, high precision, high reliability and low cost test target.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical testing and calibration, and particularly relates to a multi-range measurement device and method for characteristics of optical fiber devices. BACKGROUND

[0002] Due to the advantages of anti-electromagnetic interference, low loss, small size, sensitivity and easy integration, optical fiber devices are increasingly developed and utilized, especially in the fields of communication, sensing and precision measurement, which have deeply influenced the development of modern technology. In order to further promote the high-quality preparation and application of optical fibers and optical fiber devices, it is necessary to accurately test and characterize various parameters and characteristics of optical fibers and optical fiber devices. The existing characteristic testing devices and methods of optical fibers and optical fiber devices can be classified according to the target testing parameters, and can be divided into optical parameters, mechanical parameters and thermal parameters according to the nature of the parameters. Among them, optical parameters are very important in the field of basic measurement, and therefore must be faced in the development and design of testing instruments and measurement methods.

[0003] According to whether the optical fiber and optical fiber device characteristic parameter acquisition method is direct or not, it can be divided into direct parameter measurement and indirect parameter measurement. Indirect parameter measurement is more focused on the functional characteristics of optical fibers and optical fiber devices, and is particularly needed in high-quality application and front-end development. It is generally necessary to achieve a breakthrough in bottleneck and develop new paths and methods in modern evaluation and analysis. Generally, indirect parameters can be divided into amplitude intensity and phase characteristics, which are mainly obtained by measuring the transmission change of optical signals in optical fibers and optical fiber devices to inverse the optical characteristics of the measured optical fiber or optical fiber device.

[0004] At present, for the measurement of amplitude intensity parameters of optical fibers and optical fiber devices, the main application equipment and devices are optical spectrum analyzers, spectrophotometers, optical power meters, etc. Generally, the amplitude-frequency characteristic parameters of the target optical fiber or optical fiber device are obtained by using the truncation method, transmission method, insertion method, return loss method, etc. It is easy to achieve for long optical fibers or optical fibers and optical fiber devices with relatively large loss and gain, but the measurement effect is poor for some special small parameters, such as low-loss passive optical fibers, low-gain active optical fibers, low-reflectivity / transmissivity fiber gratings, and low-extinction-loss fiber attenuators. The current testing technology has limited ability to process and identify weak signals, and can only rely on the inherent sensitivity limit of the spectrum analyzer power meter for forced testing, lacking effective optical enhancement methods and structural devices for extremely weak signals.

[0005] For the measurement of phase characteristic parameters of optical fibers and optical fiber devices, more expensive tunable modulation type light sources, ultrafast / pulse light sources, and optical frequency comb are relied on, and high-speed multifunctional detectors such as vector network analyzers are used for collection, or spectral detection devices are used for spatial scale detection under the time scale or beat frequency, and the target to-be-measured phase frequency parameters are obtained by discrete splicing combination. Essentially, the existing technology and method are limited by the performance of the light source, and the cost performance is low, and the measurement result does not have good stability and continuity in the wavelength domain. SUMMARY

[0006] Therefore, the present application aims to provide a multi-range measurement device and method for optical fiber device characteristics, which combines the advantages of traditional low-coherence optical fiber measurement devices, introduces a multi-range optical fiber ring test structure, fully integrates the characteristics of various commonly used optical fibers and optical fiber devices, perfects the optical fiber ring access method, and cooperates with a complete and perfect calibration correction model to realize differentiated testing of matching differences, achieve the testing target effect of multiple types, multiple parameters, high precision, high reliability, and low cost with one device, and break through the limit precision and measurement capability of the traditional measurement method.

[0007] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0008] A multi-range measurement device for optical fiber device characteristics, comprising a low-coherence demodulation detection module, a measurement access detection module, a reflection dynamic scanning module, a spatial scanning positioning module, and an industrial control circuit module; a to-be-measured object is accessed into the measurement access detection module, and forms a circulating test optical path with the measurement access detection module; the low-coherence demodulation detection module generates reference light and test light, the reference light is scanned by the spatial optical path of the reflection dynamic scanning module and then returns to the low-coherence demodulation detection module for signal enhancement; the test light is scanned by the spatial optical path of the reflection dynamic scanning module and then enters the measurement access detection module for enhancement; the measurement access detection module and the to-be-measured object perform multi-range circulating transmission on the enhanced test light; the test light after multi-range circulating transmission is output by the measurement access detection module and scanned by the spatial optical path of the reflection dynamic scanning module and then returns to the low-coherence demodulation detection module; the low-coherence demodulation detection module interferes the enhanced reference light and the received test light to obtain a first interference result; the spatial scanning positioning module performs spatial continuous scanning on the reflection dynamic scanning module, the spatial scanning positioning module receives reflected light from the reflection dynamic scanning module, the reflected light interferes with the light emitted by the spatial scanning positioning module to obtain a second interference result; and the industrial control circuit module obtains a multi-range measurement signal of the to-be-measured object according to the first interference result and the second interference result.

[0009] Further, the low-coherence demodulation detection module comprises a broadband light source assembly, a reference arm, a test arm, and a detection assembly; wherein: the broadband light source assembly is configured to generate reference light and test light; the reference arm is configured to receive the reference light from the reflection dynamic scanning module and to perform signal enhancement on the received reference light; the test arm is configured to receive the test light from the reflection dynamic scanning module; and the detection assembly is configured to collect the reference light from the reference arm and the test light from the test arm, and to perform interference and detection on the reference light and the test light to obtain a first interference result.

[0010] Further, the broadband light source assembly comprises a broadband light source and a fiber optic splitter; wherein the broadband light source emits broadband white light, and the broadband white light forms the reference light and the test light after passing through the fiber optic splitter.

[0011] Further, the reference arm comprises a fiber optic polarization controller and a fiber optic attenuator; the reference light from the reflection dynamic scanning module is processed by the fiber optic polarization controller and the fiber optic attenuator in sequence to complete the signal enhancement.

[0012] Further, the test arm comprises a fiber optic circulator and a test arm fiber; the reference light output by the fiber optic splitter is transmitted to the reflection dynamic scanning module through the fiber optic circulator; and the test light from the reflection dynamic scanning module enters the test arm fiber after passing through the fiber optic circulator, and the test arm fiber transmits the test light to the detection assembly.

[0013] Further, the detection assembly comprises a broadband light collection coupler, a first broadband light balanced detector, and a second broadband light balanced detector; wherein the broadband light collection coupler collects the reference light from the fiber optic attenuator and the test light from the test arm fiber, the first broadband light balanced detector and the second broadband light balanced detector detect the first interference result after the two beams of light interfere to obtain the first interference result, and the first interference result is sent to the industrial control circuit module.

[0014] Further, the industrial control circuit module performs differential operation on the detection results of the first broadband light balanced detector and the second broadband light balanced detector.

[0015] Further, the measurement access detection module comprises a pump laser light source, a fiber wavelength division multiplexer, a doped fiber, a test fiber coupler, an input multi-pass fiber and an output multi-pass fiber; wherein the pump laser light source emits pump laser light, the fiber wavelength division multiplexer collects the pump laser light and test light from the reflection dynamic scanning module, and couples the two beams of light into the doped fiber, the doped fiber is affected by the pump laser light, and the test light from the reflection dynamic scanning module is amplified; the amplified test light enters the input multi-pass fiber after passing through the test fiber coupler; the measured object is connected with the output end of the input multi-pass fiber and the input end of the output multi-pass fiber, so that the amplified test light is transmitted in the circulating test light path composed of the test fiber coupler, the input multi-pass fiber, the measured object and the output multi-pass fiber; when the circulating test light is reflected in the measured object, the reflected test light is transmitted to the reflection dynamic scanning module along the input multi-pass fiber, the test fiber coupler, the doped fiber and the fiber wavelength division multiplexer, and the reflection dynamic scanning module reflects the transmitted test light into the low-coherence demodulation detection module.

[0016] Further, fiber polarization controllers are arranged on the input multi-pass fiber and the output multi-pass fiber, and the two fiber polarization controllers respectively control the polarization of the test light in the input multi-pass fiber and the output multi-pass fiber.

[0017] Further, the measurement access detection module further comprises a Fresnel reflection device, the test fiber coupler transmits part of the test light from the doped fiber to the Fresnel reflection device, and part of the test light is reflected by the Fresnel reflection device to form background light with background information of the measurement access detection module; the background light is reflected along the path of the test fiber coupler, the doped fiber and the fiber wavelength division multiplexer.

[0018] Further, the reflection dynamic scanning module comprises a scanning displacement table and a mirror group, the reference light from the low-coherence demodulation detection module is reflected by the mirror group back to the low-coherence demodulation detection module, and the test light from the low-coherence demodulation detection module is reflected by the mirror group into the measurement access detection module; the test light from the measurement access detection module is reflected by the mirror group back to the low-coherence demodulation detection module; the scanning displacement table drives the mirror group to move, so that the transmitted reference light and test light are scanned in space.

[0019] Further, the spatial scanning positioning module comprises a positioning laser light source, a positioning laser coupler, a positioning end reflector, a reference end reflector, and a positioning laser detector; wherein the positioning laser light source emits positioning laser light to the reflector group through the positioning laser coupler, and the positioning laser light enters the reference end reflector after being reflected by the reflector group; the reference end reflector reflects the positioning laser light coming from the reference end reflector back to the reflector group, the reflector group reflects the positioning laser light from the reference end reflector to the positioning end reflector, and the positioning end reflector transmits the positioning laser light to the positioning laser coupler; the positioning laser coupler couples the positioning laser light from the positioning laser light source and the positioning end reflector, the coupled laser light is input to the positioning laser detector for interference detection to obtain a second interference result; and the positioning laser detector sends the second interference result to the industrial control circuit module.

[0020] Further, the industrial control circuit module comprises an industrial control computer host, a pump laser light source controller, a low-coherence signal acquisition card, and a positioning interference signal trigger; the positioning interference signal trigger generates a trigger signal according to the interference signal collected by the spatial scanning positioning module, and transmits the trigger signal to the low-coherence signal acquisition card; the low-coherence signal acquisition card receives the first interference result triggered by the trigger signal; the pump laser light source controller is used to control the measurement access detection module to emit pump laser light for enhancing the test light; and the industrial control computer host receives and processes the first interference result to obtain a multi-range measurement signal, and controls the pump laser light source controller, the low-coherence signal acquisition card, and the positioning interference signal trigger.

[0021] A multi-range measurement method for characteristics of an optical fiber device, comprising:

[0022] S1: preliminarily determining and estimating the structure and performance of the object to be measured;

[0023] S2: establishing a multi-range measurement device for characteristics of an optical fiber device according to the estimation result of step S1, and determining an optical path length parameter in the multi-range measurement device;

[0024] S3: determining the spatial positions of the measurement signal and the reference background signal under different ranges according to the inherent parameters of the object to be measured and the estimation result of step S1, and combining the optical path length parameter obtained in step S2;

[0025] S4: according to the spatial positions of the detection signal and the reference background signal determined in step S3, the spatial scanning positioning module continuously scans the reflection dynamic scanning module in space, obtains laser spatial interference fringes, and sends the laser spatial interference fringes to the industrial control circuit module to obtain a spatially distributed multi-range interference pattern, which is the multi-range measurement signal;

[0026] S5: based on the multiple pass interference pattern obtained in step S4, obtaining the intensity amplitude characteristic information value and the phase characteristic information value of the to-be-tested object, and completing the characteristic test analysis of the to-be-tested object.

[0027] Further, between step S2 and step S3, further comprising: adjusting the signal light power in the measurement arm and the reference arm of the multiple pass test system according to the existing parameters of the to-be-tested object, the performance estimation obtained in step S1, and the connection point number and the connection loss estimation of the to-be-tested object after accessing the multiple pass measurement device in step S2.

[0028] Further, step S5 further comprises: obtaining the corresponding relationship of the measurement signal and the reference background signal under different pass values according to the spatial corresponding positions of the measurement signal and the reference background signal in step S3, dividing the intensity amplitude and the phase characteristic under different pass values to restore the coefficient, and completing the calibration by supplementing the spectrum test.

[0029] Further, the method further comprises:

[0030] S6: comparing the characteristic information value obtained in step S5 with the estimation value in step S1, and comparing the background interference information value magnitude of the reference background signal in step S3, to determine whether the interface connection mode of the to-be-tested object accessing the multiple pass measurement device needs to be adjusted: if adjustment is needed, repeating the operation of step S2 and adjusting the interface connection mode, and then repeating steps S3-S5 to complete the characteristic test analysis of the to-be-tested object; if adjustment is not needed, then directly completing the characteristic test analysis of the to-be-tested object.

[0031] Compared with the prior art, the application can achieve the following beneficial effects:

[0032] (1) In the multiple pass measurement device and method for the characteristic of the optical fiber device, the amplitude intensity and phase characteristic test results of the traditional optical fiber or optical fiber device have small single information amount, and the test precision and dynamic range of the traditional interference type test method are limited, and the application provides a low coherence demodulation system integrating multiple intensity adjustment technologies and stable control technologies, which is combined with the optical fiber ring access optical path, can realize the overall low-cost high-performance multiple pass characteristic test function, effectively reduces the measurement result uncertainty through the linear reduction of the multiplied parameters, improves the test precision and accuracy in principle, breaks through the traditional theoretical limit, and is extremely important for the test of weak parameters and characteristics. In addition, combined with the traditional amplitude intensity test calibration, such as transmission and reflection spectrum test, the supplementary calibration can be realized systematically from the method level, so that the high-standard optical fiber or optical fiber integrated device characteristic test can be realized by the low-cost equipment in the whole process.

[0033] (2) The multi-range measuring device and method for the characteristics of the optical fiber device provided by the application can be adjusted and developed for use, and has strong flexibility. In addition, the device provided by the application takes into account the mainstream amplitude intensity characteristics and phase characteristics test requirements, and comprehensively excludes test interference or influencing factors from the perspective of software composition. The multi-range optical fiber ring part can realize low-loss or non-destructive access of multiple types of target test objects. The intensity adjustment scheme in the application comprehensively considers polarization fading, connection loss, coupling loss, end Fresnel strong reflection, and many other problems and technologies such as separate intensity changes of the measurement arm and the reference arm. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the application and are incorporated herein for reference. The illustrative embodiments of the present application and their description serve to explain the application. They do not, however, limit the present application, which is defined solely by the appended claims.

[0035] Figure 1 The overall structure schematic diagram of the multi-range measuring device for the characteristics of the optical fiber device is described in the embodiments of the application.

[0036] Figure 2 The schematic diagram of the optical fiber grating access measurement access detection module is described in the embodiments of the application.

[0037] Figure 3 The schematic diagram of the photonic crystal fiber non-contact access measurement access detection module is described in the embodiments of the application.

[0038] Figure 4 The schematic diagram of the multi-core optical fiber non-contact access measurement access detection module is described in the embodiments of the application.

[0039] Figure 5 The schematic diagram of the measurement access detection module during background calibration is described in the embodiments of the application.

[0040] Figure 6 The flowchart of the multi-range measuring method for the characteristics of the optical fiber device is described in the embodiments of the application.

[0041] BRIEF DESCRIPTION OF DRAWINGS

[0042] 1, broadband light source; 2, fiber optic light splitting coupler; 3, fiber optic polarization controller; 4, fiber optic attenuator; 5, fiber optic circulator; 6, test arm fiber; 7, broadband light collection coupler; 8, first broadband light balanced detector; 9, second broadband light balanced detector; 10, fiber collimator; 11, pump laser light source; 12, fiber optic wavelength division multiplexer; 13, doped fiber; 14, test fiber coupler; 15, input multi-pass fiber; 16, output multi-pass fiber; 17, fiber optic polarization controller; 18, Fresnel reflector; 19, scanning displacement stage; 20, mirror set; 21, positioning laser light source; 22, positioning laser coupler; 23, positioning end reflector; 24, reference end reflector; 25, positioning laser detector; 26, industrial control computer host; 27, pump laser light source controller; 28, low coherence signal acquisition card; 29, positioning interference signal trigger; 30, fiber grating; 31, photonic crystal fiber; 32, multi-core fiber. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not constitute a limitation on the present application.

[0044] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0045] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0046] In the description of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "mounting", "connected", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0048] The multi-path measurement device for optical fiber device characteristics described in the embodiments of the present application integrates and integrates a variety of optical fiber optical path advantage characteristics, and the system includes a test demodulation part and a to-be-measured access part based on optical path, and a circuit connection part for electrical control connection and data acquisition. Multi-path refers to multi-optical path technology, that is, the technology of increasing the total distance of light propagation in the system by repeatedly reflecting the light in a specific path. Specifically, as shown in Figure 1 The multi-path measurement device for optical fiber device characteristics described in the embodiments of the present application includes a low-coherence demodulation detection module, a measurement access detection module, a reflection dynamic scanning module, a spatial scanning positioning module, and an industrial control circuit module. Among them, the to-be-measured object is accessed into the measurement access detection module, and forms a circulating test optical path with the measurement access detection module; the low-coherence demodulation detection module generates reference light and test light, the reference light is scanned by the spatial optical path of the reflection dynamic scanning module and then returns to the low-coherence demodulation detection module for signal enhancement; the test light is scanned by the spatial optical path of the reflection dynamic scanning module and then enters the measurement access detection module for enhancement; the measurement access detection module and the to-be-measured object perform multi-path circulation transmission on the enhanced test light; the test light after multi-path circulation transmission is output by the measurement access detection module, and after being scanned by the spatial optical path of the reflection dynamic scanning module, it returns to the low-coherence demodulation detection module; the low-coherence demodulation detection module interferes the enhanced reference light and the received test light to obtain a first interference result; the spatial scanning positioning module continuously scans the reflection dynamic scanning module, and the spatial scanning positioning module receives the reflected light from the reflection dynamic scanning module, and the reflected light interferes with the light emitted by the spatial scanning positioning module to obtain a second interference result; the industrial control circuit module obtains the multi-path measurement signal of the to-be-measured object according to the first interference result and the second interference result.

[0049] In some embodiments, the low-coherence demodulation detection module is as shown in Figure 1As shown, the system comprises a broadband light source assembly, a reference arm, a test arm and a detection assembly. The broadband light source assembly is configured to generate reference light and test light, the reference arm is configured to receive the reference light from the reflection dynamic scanning module and to perform signal enhancement on the received reference light, the test arm is configured to receive the test light from the reflection dynamic scanning module, and the detection assembly is configured to collect the reference light from the reference arm and the test light from the test arm, and to perform interference and detection on the reference light and the test light to obtain a first interference result.

[0050] Specifically, the broadband light source assembly comprises a broadband light source 1 and a fiber optic coupler 2. The broadband light source 1 emits broadband white light, and the broadband white light forms reference light and test light after passing through the fiber optic coupler 2. The reference arm comprises a fiber optic polarization controller 3 and a fiber optic attenuator 4. The reference light from the reflection dynamic scanning module is sequentially processed by the fiber optic polarization controller 3 and the fiber optic attenuator 4 to complete signal enhancement. The test arm comprises a fiber optic circulator 5 and a test arm fiber 6. The reference light output by the fiber optic coupler 2 is transmitted to the reflection dynamic scanning module through the fiber optic circulator 5, the test light of the reflection dynamic scanning module enters the test arm fiber 6 after passing through the fiber optic circulator 5, and the test arm fiber 6 transmits the test light to the detection assembly. The detection assembly comprises a broadband light collecting coupler 7, a first broadband light balanced detector 8 and a second broadband light balanced detector 9. The broadband light collecting coupler 7 collects the reference light from the fiber optic attenuator 4 and the test light from the test arm fiber 6. After the reference light and the test light interfere to obtain a first interference result, the first broadband light balanced detector 8 and the second broadband light balanced detector 9 detect the first interference result and send it to the industrial control circuit module. In the embodiment of the present application, the fiber optic polarization controller 3 receives the reference light from the reflection dynamic scanning module through the fiber, the fiber optic circulator 5 receives the test light from the reflection dynamic scanning module through the fiber, and the two fiber input ends are provided with a fiber collimator 10. That is, the reference light and the test light from the reflection dynamic scanning module are collimated by the fiber collimator 10 and then enter the fiber optic polarization controller 3 and the fiber optic circulator 5 through the corresponding input fibers. The first broadband light balanced detector 8 and the second broadband light balanced detector 9 detect interference signals, and the detection target quantity is consistent. The difference lies in that the detection phases of the first broadband light balanced detector 8 and the second broadband light balanced detector 9 are opposite or complementary. It can be understood that the two states of the optical signal interference are detected, and the difference operation is performed on the detection results of the two states to eliminate the direct current intensity value. In the difference process of the first broadband light balanced detector 8 and the second broadband light balanced detector 9, the common noise is cancelled out, and the interference signal part carrying information, i.e. the interference quantity, is effectively extracted. This makes the system insensitive to light source fluctuations and enables stable measurement in harsh environments.

[0051] In this invention, the fiber polarization controller 3 adjusts the polarization state of the input reference light, which can counteract polarization fading caused by twisting, entanglement, and external compression of some components in the optical path during the measurement process. The fiber attenuator 4 can freely adjust the intensity and power of the reference light in the subsequent reference arm, achieving attenuation control of the adjusted reference light. The two work together to adjust the intensity of the returned reference light, achieving maximum compatibility with the dynamic range of light intensity. In this embodiment, the test arm fiber 6 is preferably made of single-mode fiber, which can ensure stability to the greatest extent while also having sufficient low-cost advantages.

[0052] In some embodiments, the measurement access detection module, such as Figure 1 As shown, the system includes a pump laser source 11, a fiber wavelength division multiplexer 12, an erbium-doped fiber 13, a test fiber coupler 14, an input multi-path fiber 15, and an output multi-path fiber 16. The pump laser source 11 emits a pump laser beam. The fiber wavelength division multiplexer 12 collects the pump laser beam and the test light from the reflection dynamic scanning module, and couples both beams into the erbium-doped fiber 13. Under the influence of the pump laser, the erbium-doped fiber 13 amplifies the test light from the reflection dynamic scanning module. The amplified test light then passes through the test fiber coupler 14 and enters the input multi-path fiber 15. The object under test (DUT) is connected to the output end of the input multi-path fiber 15 and the input end of the output multi-path fiber 16, allowing the amplified test light to circulate through the test fiber coupler 14, the input multi-path fiber 15, the DUT, and the output multi-path fiber 16 in a multi-path loop. When the test light transmitted in a loop is reflected in the object under test, the reflected test light is transmitted along the input multi-path fiber 15, the test fiber coupler 14, the erbium-doped fiber 13, and the fiber wavelength division multiplexer 12 to the reflection dynamic scanning module. The reflection dynamic scanning module reflects the transmitted test light into the low coherence demodulation detection module.

[0053] In this invention, the pump laser source 11 emits a pump laser to the erbium-doped fiber 13. The erbium-doped fiber 13, excited by the pump laser, undergoes stimulated emission amplification, thereby enhancing the test light of the transmitted broadband white light. This method of optical signal enhancement, under the adjustment and control of such an amplifier, does not alter the interference effect between the transmitted signal light and the reference arm, while still allowing for precise control of the intensity of the measurement arm. The amplified test light continues to be transmitted to the test fiber coupler 14. The test fiber coupler 14 is crucial for achieving a multi-range transmission path. Its access method differs from traditional fiber optic ring mirror structures. Taking a 2×2 fiber coupler as an example, the two fiber branches on which the ring relies must ensure that there is one input port and one output port to ensure the completion of several clockwise or counterclockwise transmissions.

[0054] In some embodiments, the fiber polarization controller 17 is arranged on both the input multi-pass fiber and the output multi-pass fiber, and the two fiber polarization controllers 17 respectively control the polarization of the test light in the input multi-pass fiber 15 and the output multi-pass fiber 16. In the present application, the fiber polarization controller 17 is connected in the loop test light path composed of the test fiber coupler 14, the input multi-pass fiber 15, the object to be measured, and the output multi-pass fiber 16, which on one hand suppresses the polarization fading problem, and on the other hand can dynamically and continuously adjust the measurement of the birefringence parameter of the object to be measured.

[0055] In some embodiments, the measurement access probe module further comprises a Fresnel reflection device 18, and the test fiber coupler 14 transmits part of the test light from the doped fiber 13 into the Fresnel reflection device 18, and the part of the test light is reflected by the Fresnel reflection device 18 to form background light with background information of the measurement access probe module. The background light is reflected along the path of the test fiber coupler 14, the doped fiber 13, and the fiber wavelength division multiplexer 12. The Fresnel reflection device 18 comprises a matching liquid with a known refractive index. Thus, the present application provides a multi-pass measurement device for the characteristics of the fiber device, which completes the intensity adjustment through the combination of the fiber optical splitter coupler 2, the fiber attenuator 4, the fiber circulator 5, the pump laser light source 11, the fiber wavelength division multiplexer 12, and the doped fiber 13, and the matching liquid in the Fresnel reflection device 18, wherein the splitting ratio control of the fiber optical splitter coupler 2 is controlled, the attenuation degree of the reference light by the fiber attenuator 4 is controlled, the one-way back light access of the fiber circulator 5 is controlled, the gain control of the test light by the combination of the pump laser light source 11, the fiber wavelength division multiplexer 12, and the doped fiber 13 is controlled, and the quantitative anti-reflection control of the matching liquid in the Fresnel reflection device 18 is controlled. The above-mentioned intensity adjustment operation of the present application can effectively solve the problems of weak signal difficult to detect or strong signal detection voltage saturation, and is the key to effectively enhance the measurement capability and limit of the device.

[0056] It can be understood that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments are only used to illustrate the present application. Figure 1, the test light input into the test fiber coupler 14 is split into two parts at the test fiber coupler 14 for the first time, one part of the test light enters the fiber polarization controller 17 via the input multi-pass fiber 15, and then enters the object to be measured in the form of first single-pass via the output end of the input multi-pass fiber 15. This part of the signal light will continue to be transmitted forward in the object to be measured and pass through, until it reaches the input end of the output multi-pass fiber 16, and then enters the test fiber coupler 14 for the second time after being adjusted by the fiber polarization controller 17, and then the subsequent transmission path is similar to the previous transmission path, and can reach the fiber polarization controller 17 for the second time in order, and then the signal light enters the object to be measured again, which is a two-pass test form. If the test light in the object to be measured is reflected at this time, the reflected test light will be transmitted back to the fiber circulator 5 in the low-coherence demodulation probe module in the form of back transmission along the input multi-pass fiber 15, the test fiber coupler 14, the doped fiber 13, and the fiber wavelength division multiplexer 12, and will be combined with the reference light under the light collection and combination of the wide-spectrum light collection coupler 7, which constitutes a two-pass test link. The forward transmission test light can also continue to propagate in the circulating test light path, and can be wrapped around the loop for the second time and the third time in the same form, so that signal light modulation under different passes can be realized, and the same original route can be returned to realize interference with the reference light, and the test signals under different passes are spatially distributed independently, that is, the optical path positions of different pass test results are different.

[0057] The test fiber coupler 14 transmits another part of the test light into the Fresnel reflection device 18, which constitutes the Fresnel reflection of the original route. The propagation of this part of the test light is not affected by the circulating test light path, but carries all the background information of the measurement access probe module, so it can be effectively used to eliminate background interference. Moreover, the fiber length of this part is also independent of the spatial distribution of the reflected signal light in the fiber ring and does not interfere with each other.

[0058] In some embodiments, the reflection dynamic scanning module is as shown in FIG. 6. Figure 1As shown, the spatial scanning positioning module includes a scanning displacement stage 19 and a mirror group 20. The scanning displacement stage 19 drives the mirror group 20 to move, so that the transmitted reference light and test light are subjected to spatial optical path scanning. The reference light from the low-coherence demodulation probe module is reflected by the mirror group 20 back to the low-coherence demodulation probe module, the test light from the low-coherence demodulation probe module is reflected by the mirror group 20 into the measurement access probe module, and the test light from the measurement access probe module is reflected by the mirror group 20 back to the low-coherence demodulation probe module. In the embodiment of the present application, the mirror group 20 preferably adopts a W-type mirror group. At this time, the reference light from the low-coherence demodulation probe module is reflected twice on the W-type mirror group and then returns to the low-coherence demodulation probe module, the test light from the low-coherence demodulation probe module is reflected twice on the W-type mirror group and then enters the measurement access probe module, and the test light from the measurement access probe module is reflected twice on the W-type mirror group and then returns to the low-coherence demodulation probe module.

[0059] In some embodiments, the spatial scanning positioning module is as shown in Figure 1 As shown, the spatial scanning positioning module includes a positioning laser light source 21, a positioning laser coupler 22, a positioning end reflecting surface 23, a reference end reflecting surface 24, and a positioning laser detector 25. The positioning laser light source 21 emits positioning laser light to the mirror group 20 through the positioning laser coupler 22, and the positioning laser light is reflected by the mirror group 20 and enters the reference end reflecting surface 24. The reference end reflecting surface 24 reflects the transmitted positioning laser light back to the mirror group 20, the mirror group 20 reflects the positioning laser light from the reference end reflecting surface 24 into the positioning end reflecting surface 23, and the positioning end reflecting surface 23 transmits the positioning laser light to the positioning laser coupler 22. The positioning laser coupler 22 couples the positioning laser light from the positioning laser light source 21 and the positioning end reflecting surface 23, and the coupled laser light is input to the positioning laser detector 25 for interference detection to obtain a second interference result. The positioning laser detector 25 sends the second interference result to the industrial control circuit module. The application of the spatial scanning positioning module can effectively improve the positioning accuracy of the scanning mirror and effectively reduce the measurement failure rate. Preferably, in some embodiments, the optical fibers between the positioning laser coupler 22 and the reference end reflecting surface 24 and the optical fibers between the positioning laser coupler 22 and the positioning end reflecting surface are wound and placed in parallel. In addition to realizing the spatial parallel and compact packaging of the spatial scanning positioning module, the mechanical robustness of the spatial scanning positioning module can also be increased.

[0060] In some embodiments, the industrial control circuit module is as shown in Figure 1The shown includes industrial computer host 26, pump laser light source controller 27, low coherence signal acquisition card 28 and positioning interference signal trigger 29. The positioning interference signal trigger 29 generates a trigger signal according to the spatial scanning positioning module collected interference signal, and transmits the trigger signal to the low coherence signal acquisition card 28. The low coherence signal acquisition card 28 is triggered by the trigger signal, and receives the first interference result. The pump laser light source controller 27 is used to control the measurement access detection module to emit the pump laser for enhancing the test light. Specifically, the pump laser light source controller 27 controls the pump laser light source 11 to emit the pump laser. The industrial computer host 26 receives the pump laser light source controller 27, the low coherence signal acquisition card 28 and the positioning interference signal trigger 29, receives and processes the first interference result, and obtains the multiple range measurement signal.

[0061] The multiple range measurement device for optical fiber device characteristics provided by the application can perform multiple range measurement on various optical fiber devices. When the to-be-measured object is an optical fiber grating 30, it is directly accessed into the measurement access detection module in the manner as shown in Figure 2 Specifically, the two ends of the optical fiber grating 30 are respectively fused together with the output end of the input multiple range optical fiber 15 and the input end of the output multiple range optical fiber 16, which can effectively avoid the redundant reflection surface. However, the reserved length of the input multiple range optical fiber 15 and the output multiple range optical fiber 16 needs to be paid attention to during connection to avoid the cross-over of the optical fiber end reflection signal. When the to-be-measured object is a special type optical fiber such as a photonic crystal fiber and a polymer optical fiber, taking the photonic crystal fiber 31 as an example, considering the numerical aperture, end face fusion difficulty and other factors, a fiber collimator 10 or the like can be used to realize non-contact and non-destructive multiple range access through free space optical transmission transition, as shown in Figure 3 Specifically, the fiber collimator 10 is connected to the output end of the input multiple range optical fiber 15 and the input end of the output multiple range optical fiber 16. The test light in the input multiple range optical fiber 15 enters the photonic crystal fiber 31 through the fiber collimator 10, and the test light output by the photonic crystal fiber 31 enters the output multiple range optical fiber 16 through the fiber collimator 10, which can effectively avoid the problems such as hole collapse, loss and unpredictable mode excitation of the photonic crystal fiber when it is fused with a single-mode optical fiber. When the to-be-measured object is a coarse-diameter multi-mode or multi-core optical fiber and optical fiber device, taking the multi-core optical fiber 32 as an example, it can also be accessed into the device provided by the application and realize multiple range high-precision testing. In this case, the optical fiber ring part can be appropriately adjusted, and a cross multiple range test scheme can be introduced, as shown in Figure 4As shown, specifically, no less than two pairs of input multi-pass optical fiber 15 and output multi-pass optical fiber 16 are coupled with the test optical fiber coupler 14, and a fiber polarization controller 17 is arranged on each of the input multi-pass optical fiber 15 and the output multi-pass optical fiber 16. Meanwhile, a fiber collimator 10 is arranged at the end of the multi-core optical fiber 32 adjacent to all the input multi-pass optical fiber 15 and the output multi-pass optical fiber 16. The test light in the plurality of input multi-pass optical fiber 15 enters the multi-core optical fiber 32 through the fiber collimator 10, and the test light output by the multi-core optical fiber 32 enters the plurality of output multi-pass optical fiber 16 through the fiber collimator 10. The cross multi-pass test scheme can be mainly used to evaluate the crosstalk between different core diameters or modes in the optical fiber. In addition, for optical fibers or optical fiber devices with relatively short lengths, the cross multi-pass test of the core diameter and the cladding can also be used to detect the intensity characteristics such as energy leakage or cladding leakage caused by an undesirable fiber core.

[0062] The device provided by the application can also calibrate and test the optical path structure and background interference of itself. As shown, the output end of the input multi-pass optical fiber 15 and the input end of the output multi-pass optical fiber 16 are directly fused together. Figure 5 As shown, the intensity characteristics and phase characteristics of the non-test object part in the circulating test optical path can be tested to detect the polarization control effect in the circulating test optical path, calibrate the background loss of the optical fiber ring, and exclude the background dispersion of the optical fiber ring. In addition, the background interference calibration also includes measuring the intensity and phase characteristics calibration outside the circulating test optical path in the access detection module. However, this part of the calibration does not need to be adjusted additionally, and only needs to change the matching liquid in the Fresnel reflector 18. By replacing the matching liquid with a known refractive index, the Fresnel reflection signal intensity in the Fresnel reflector 18 can realize the calibration and calibration of the measurement signal intensity. This is the inherent advantage of the single-mode optical fiber low-coherence optical path, and is also the intensity calibration strategy often ignored in traditional test devices.

[0063] In the embodiment of the present application, all the optical paths are connected by single-mode optical fibers, which maximally ensures stability while having sufficient low-cost advantage. Considering that the application wavelength of the optical fiber and optical fiber device to be tested at present is mainly the communication wavelength band near 1550 nm, the device provided by the present application takes the optical path and device with a 1550 nm center wavelength band as an example, and in the expansion of the present application, it can also be applied to the test development of other center wavelength bands. Generally, the main wavelength matching replacement is for the working wavelength of the optical fiber or optical fiber device to be tested, which can be in the visible light band, near the 850 nm window band, near the 1310 nm window band, near the 1550 nm window band, and in the larger near-infrared band. For the test of different working wavelength samples in the device, the light source, single-mode optical fiber, detector, and other optical fiber components need to be adjusted accordingly. However, the space scanning positioning module in the device does not need to be matched and replaced, because it only plays a positioning function for the scanning mirror group and does not involve optical signal testing. In addition, in the device provided by the present application, the connection of the device with the attached fiber can be flexibly and detachably connected by the optical fiber flange. If applied in a specific working wavelength condition, the tail fibers of each part can be directly fused, reducing the possible Fresnel reflection stray interference signal at the flange interface.

[0064] The present application also provides a method for measuring the characteristics of an optical fiber device with multiple times, which combines Figure 1 and Figure 6 , the method comprising:

[0065] S1: preliminarily determining and estimating the structure and performance of the object to be tested.

[0066] For step S1, the type and target parameters of the object to be tested can include the loss of passive optical fiber, the absorption or gain of active optical fiber, the wavelength domain intensity gating capability of optical fiber grating filter device, the extinction capability of optical fiber attenuator, the loss or splitting ratio of optical fiber coupler, the target amplitude intensity characteristics such as the gradual fluorescence darkening and quenching of active optical fiber; it can also include the target phase characteristics such as the communication optical fiber dispersion, photonic crystal fiber dispersion, active optical fiber group velocity dispersion, optical fiber grating group delay or differential group delay, and coupling dispersion of optical fiber coupler. These target types and target parameters have strong correlation and strong matching with the device and the method provided by the present application.

[0067] S2: according to the results of the estimation of step S1, establishing the device for measuring the characteristics of an optical fiber device with multiple times provided by the present application, and determining the optical path length parameter in the device for measuring the characteristics of an optical fiber device with multiple times.

[0068] For step S2, the optical path length adjustment can be to select optical fiber jumpers of different lengths, or to directly insert single-mode optical fibers of different lengths into the reference arm, or to insert a length-adjusting optical fiber into the measurement arm in the case of an excessively long reference arm. For the case where the core size of the target optical fiber does not match the single-mode optical fiber optical path portion, mature technologies such as fusion splicing and fusion taper can be introduced to reduce the loss and light leakage at the splicing point, or a spatial light collimation coupling method can be used.

[0069] S3: According to the inherent parameters of the target object and the results of the performance estimation in step S1, and in combination with the optical path length adjustment obtained in step S2, the spatial positions of the measurement signals and the reference background signals at different multiple ranges are determined, and the background interference analysis and testing are performed on the separated mode groups and regions, and potential intensity interference errors and background dispersion phase errors are estimated.

[0070] The spatial positions of the target detection signals of the target object at different multiple ranges and the spatial positions of the reference background signals of the fiber end face Fresnel reflection are determined. Specifically, the spatial positions of the detection signals of the target object at different multiple ranges are arranged at equal intervals in the equal multiple increase process, and the reference background signal peaks are inserted between two signal peaks, and these signal peaks interfere with each other. For example, as the spatial position increases, the target object one multiple detection signal peak, the fiber end face Fresnel reflection reference background signal, the target object two multiple detection signal peak, the fiber end face Fresnel reflection one multiple loop reference background signal, the target object three multiple detection signal peak, the fiber end face Fresnel reflection two multiple loop reference background signal, the target object four multiple detection signal peak, etc. The process of interference analysis and testing on the separated mode groups and regions includes obtaining the signal intensity and phase change at different transmission distances through the signal peaks at different spatial positions (different transmission distances represent that the light transmission has experienced different modes or regions), and obtaining the light attenuation and light phase change in different modes by subtracting the signal intensity and phase, and then stripping the interference in different modes or regions. Here, the mode groups and regions are mainly for the measurement arm optical path portion.

[0071] In some embodiments, between step S2 and step S3, there is further included: adjusting the signal optical power in the measurement arm and the reference arm of the multiple-range testing system according to the existing parameters of the target object, the performance estimation obtained in step S1, and the connection point number and connection loss estimation of the target object after being connected to the multiple-range measurement device in step S2. In this way, the high contrast of the interference signal can be ensured.

[0072] S4: Based on the spatial positions of the probe signal and the reference background signal determined in step S3, the spatial scanning positioning module continuously scans the reflection dynamic scanning module in space, obtains a laser spatial interference fringe, and sends the laser spatial interference fringe to the industrial control circuit module to obtain a spatially distributed multiple-path interference pattern, which is the multiple-path measurement signal.

[0073] In the present application, the mirror group 20 is continuously scanned in space according to the spatial positions of the probe signal and the reference background signal determined in step S3, the spatial scanning positioning module continuously records the fluctuation of the interference intensity, the positioning interference signal trigger 29 fits to obtain a laser spatial interference fringe, and converts and transmits it into a trigger signal, which is transferred to the low-coherence signal acquisition card 28. The low-coherence signal acquisition card 28 records the multiple-path interference signal of the flat detector, and obtains a spatially distributed multiple-path interference pattern after denoising processing by the industrial control computer host 26.

[0074] In the embodiment of the present application, the scanning positioning accuracy of the continuously scanned mirror group 20 is related to the signal-to-noise ratio of the laser interference signal and the interference spatial fringe period. The use of a high-stability, high-signal-to-noise ratio narrow-linewidth laser, a high-sensitivity positioning laser detector 25, and a short-wavelength laser can improve the positioning accuracy of the scanning displacement table 19 to the mirror group 20, and further improve the measurement accuracy of the device system. In addition, it is necessary to ensure that the mirror group 20 does not tilt or deflect greatly during mechanical movement, and the movement speed of the mirror group 20 will also affect the system measurement accuracy. The simultaneous double scanning of the reference light and the measurement light of the present device can complete the spatial optical path difference change with high efficiency in a short distance, but the number of turns can also be further increased to realize a large scanning range in a small volume.

[0075] In other embodiments, the data signal acquisition and processing in step S4 can also add execution operations under different polarization state conditions, which can be used for birefringence parameter measurement of the object to be measured, and can also improve the signal-to-noise ratio through the polarization state condition to suppress the polarization fading of the low-coherence test signal.

[0076] S5: Based on the multiple-path interference pattern obtained in step S4, the intensity amplitude characteristic information value and the phase characteristic information value of the object to be measured are obtained, and the characteristic test analysis of the object to be measured is completed. In the embodiment of the present application, based on the multiple-path interference pattern obtained in step S4, the discrete Fourier transform is performed combined with the Fourier spectroscopy formula theory to obtain the complex reflection coefficient of the multiple-path test signal, and the phase is obtained by taking the modulus and unwrapping to obtain the intensity amplitude characteristic information value and the phase characteristic information value of the object to be measured.

[0077] Specifically, the Fourier spectroscopy formula theory in step S5 is as follows:

[0078] The intensity distribution probe signal result with the spatial position x as the independent variable may be expressed as:

[0079] ;

[0080] wherein, λ represents the wavelength of the broadband white light emitted by the broadband light source 1, represents the power spectral density function of the broadband white light, represents the reflectivity coefficient of the target to be measured, is the phase difference of the two interference signals.

[0081] It can be found from the above formula that the intensity distribution detection signal result is the inverse Fourier transform. Under the processing of the Fast Fourier Transform (FFT), the phase result can be obtained:

[0082] ;

[0083] wherein, Im represents taking the imaginary part, and Rm represents taking the real part. The specific phase processing also includes a continuous processing method for unwrapping, which is a public conventional algorithm in the field of signal processing, which will not be expanded here. Meanwhile, the modulus can obtain the intensity amplitude characteristics.

[0084] In some embodiments, step S5 further includes: obtaining the corresponding relationship of the intensity and phase of the measurement signal and the reference background signal corresponding to different ranges according to the spatial corresponding positions of the measurement signal and the reference background signal in step S3, and using the linear restoration characteristics of the measurement signal and the reference background signal to divide the intensity amplitude and phase characteristics under different ranges to restore the coefficients, and cooperate with the supplementary spectrum test to improve the calibration.

[0085] In some embodiments, the method provided by the application further includes:

[0086] S6: comparing the characteristic information value obtained in step S5 with the estimated value in step S1, and comparing the magnitude of the background interference information value of the reference background signal in step S3, to determine whether the interface connection mode of the object to be measured accessing the multi-range measurement device needs to be adjusted:

[0087] If adjustment is needed, after repeating the operation of step S2 and adjusting the interface connection mode, steps S3-S5 are repeated to complete the characteristic test analysis of the object to be measured;

[0088] If adjustment is not needed, the characteristic test analysis of the object to be measured is directly completed.

[0089] It should be understood that the various forms of flow shown above can be used to reorder, add, or remove steps. For example, the steps recited in the present disclosure can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present disclosure are achieved, which are not limited herein.

[0090] The specific implementation described above does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An apparatus for multi-range measurement of a characteristic of an optical fiber device, comprising: The low-coherence demodulation detection module, the measurement access detection module, the reflection dynamic scanning module, the spatial scanning positioning module and the industrial control circuit module are included. The object under test is accessed into the measurement access detection module, and a circulating test light path is formed between the object under test and the measurement access detection module; the low-coherence demodulation detection module generates reference light and test light, the reference light is scanned by the spatial optical path of the reflection dynamic scanning module and then returned to the low-coherence demodulation detection module for signal enhancement; the test light is scanned by the spatial optical path of the reflection dynamic scanning module and then enters the measurement access detection module for enhancement; the measurement access detection module and the object under test perform multi-pass circulation transmission on the enhanced test light. The test light after the multi-pass circulation transmission is output from the measurement access detection module and scanned by the spatial optical path of the reflection dynamic scanning module and then returned to the low-coherence demodulation detection module. The low-coherence demodulation detection module interferes the enhanced reference light and the received test light to obtain a first interference result; the spatial scanning positioning module continuously scans the reflection dynamic scanning module, the spatial scanning positioning module receives reflected light from the reflection dynamic scanning module, and the reflected light interferes with the light emitted by the spatial scanning positioning module to obtain a second interference result; the industrial control circuit module obtains a multi-pass measurement signal of the object under test according to the first interference result and the second interference result.

2. The apparatus for multi-range measurement of properties of an optical fiber device according to claim 1, characterized in that, The low-coherence demodulation detection module includes a broadband light source assembly, a reference arm, a test arm and a detection assembly; wherein: the broadband light source assembly is used to generate the reference light and the test light; the reference arm is used to receive the reference light from the reflection dynamic scanning module and enhance the received reference light; the test arm is used to receive the test light from the reflection dynamic scanning module; and the detection assembly is used to collect the reference light from the reference arm and the test light from the test arm, and interfere and detect the reference light and the test light to obtain the first interference result.

3. The apparatus of claim 2, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. The broadband light source assembly includes a broadband light source and a fiber optic splitter; wherein the broadband light source emits broadband white light, and the broadband white light forms the reference light and the test light after passing through the fiber optic splitter.

4. The apparatus of claim 3, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. The reference arm includes a fiber optic polarization controller and a fiber optic attenuator; the reference light from the reflection dynamic scanning module is processed by the fiber optic polarization controller and the fiber optic attenuator in sequence to complete signal enhancement.

5. The apparatus of claim 4, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. The test arm includes a fiber optic circulator and a test arm fiber; the reference light output by the fiber optic splitter is transmitted to the reflection dynamic scanning module through the fiber optic circulator; the test light of the reflection dynamic scanning module enters the test arm fiber after passing through the fiber optic circulator, and the test arm fiber transmits the test light to the detection assembly.

6. The apparatus of claim 5, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. The detection assembly comprises a wide-spectrum light collection coupler, a first wide-spectrum light balanced detector and a second wide-spectrum light balanced detector; the wide-spectrum light collection coupler collects reference light from the fiber attenuator and test light from the test arm fiber, after the two beams of light interfere to obtain a first interference result, the first wide-spectrum light balanced detector and the second wide-spectrum light balanced detector detect the first interference result and send the first interference result to the industrial control circuit module.

7. The apparatus of claim 6, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. The industrial control circuit module differentiates the detection results of the first wide-spectrum light balanced detector and the second wide-spectrum light balanced detector.

8. The apparatus of claim 1, wherein the optical fiber device property is a fiber length. The measurement access detection module comprises a pump laser light source, a fiber wavelength division multiplexer, a doped fiber, a test fiber coupler, an input multi-pass fiber and an output multi-pass fiber; the pump laser light source emits pump laser light, the fiber wavelength division multiplexer collects the pump laser light and test light from the reflection dynamic scanning module and couples the two beams of light into the doped fiber, the doped fiber is affected by the pump laser light and enhances and amplifies the test light from the reflection dynamic scanning module; the enhanced and amplified test light enters the input multi-pass fiber through the test fiber coupler; the to-be-measured object is connected with the output end of the input multi-pass fiber and the input end of the output multi-pass fiber, so that the enhanced and amplified test light is transmitted in a multi-pass circulation in a circulation test light path composed of the test fiber coupler, the input multi-pass fiber, the to-be-measured object and the output multi-pass fiber; when the circulation test light is reflected in the to-be-measured object, the reflected test light is transmitted along the input multi-pass fiber, the test fiber coupler, the doped fiber and the fiber wavelength division multiplexer to the reflection dynamic scanning module, and the reflection dynamic scanning module reflects the transmitted test light into the low-coherence demodulation detection module.

9. The apparatus of claim 8, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. Fiber polarization controllers are arranged on the input multi-pass fiber and the output multi-pass fiber, and the two fiber polarization controllers respectively control the polarization of the test light in the input multi-pass fiber and the output multi-pass fiber.

10. The apparatus of claim 9, wherein the optical fiber device property is a wavelength-dependent loss of the optical fiber device. The measurement access detection module further comprises a Fresnel reflection device, the test fiber coupler transmits part of the test light from the doped fiber to the Fresnel reflection device, the part of the test light is reflected by the Fresnel reflection device to form background light with background information of the measurement access detection module; the background light is reflected along the paths of the test fiber coupler, the doped fiber and the fiber wavelength division multiplexer.

11. The apparatus for multi-range measurement of properties of optical fiber devices according to claim 1, characterized in that, The reflection dynamic scanning module comprises a scanning displacement table and a mirror group, reference light from the low-coherence demodulation detection module is reflected by the mirror group back to the low-coherence demodulation detection module, and test light from the low-coherence demodulation detection module is reflected by the mirror group into the measurement access detection module. The test light from the measurement access detection module is reflected by the mirror group back into the low-coherence demodulation detection module; the scanning displacement table drives the mirror group to move, so that the transmitted reference light and test light perform spatial optical path scanning.

12. The apparatus for multi-range measurement of properties of an optical fiber device according to claim 11, wherein, The spatial scanning positioning module comprises a positioning laser light source, a positioning laser coupler, a positioning end reflective surface, a reference end reflective surface and a positioning laser detector; wherein the positioning laser light source emits positioning laser light to the mirror group through the positioning laser coupler, and the positioning laser light enters the reference end reflective surface after being reflected by the mirror group; the reference end reflective surface reflects the transmitted positioning laser light back to the mirror group, the mirror group reflects the positioning laser light from the reference end reflective surface to the positioning end reflective surface, and the positioning end reflective surface transmits the positioning laser light to the positioning laser coupler; the positioning laser coupler couples the positioning laser light from the positioning laser light source and the positioning end reflective surface, and the coupled laser light is input into the positioning laser detector for interference detection to obtain the second interference result; and the positioning laser detector sends the second interference result to the industrial control circuit module.

13. The apparatus for multi-range measurement of properties of optical fiber devices according to claim 1, characterized in that, The industrial control circuit module comprises an industrial control computer host, a pump laser light source controller, a low-coherence signal acquisition card and a positioning interference signal trigger; The positioning interference signal trigger generates a trigger signal according to the second interference result and transmits the trigger signal to the low-coherence signal acquisition card; The low-coherence signal acquisition card is triggered by the trigger signal and receives the first interference result; The pump laser light source controller is used to control the measurement access detection module to emit pump laser light for enhancing the test light; The industrial control computer host receives the pump laser light source controller, the low-coherence signal acquisition card and the positioning interference signal trigger, receives and processes the first interference result to obtain the multi-range measurement signal.

14. A method of multi-range measurement of a property of an optical fiber device, characterized by, Comprise: S1: preliminarily determine and estimate the structure and performance of the object to be measured; S2: according to the estimation result of step S1, establish the multi-range measurement device for the characteristics of the optical fiber device as claimed in any one of claims 1-13, and determine the optical path length parameter in the multi-range measurement device; S3: according to the inherent parameters of the object to be measured and the estimation result of step S1, and in combination with the optical path length parameter obtained in step S2, determine the spatial positions of the measurement signal and the reference background signal under different ranges; S4: according to the spatial positions of the detection signal and the reference background signal determined in step S3, the spatial scanning positioning module continuously scans the reflection dynamic scanning module in space, obtains laser spatial interference fringes, and sends the laser spatial interference fringes to the industrial control circuit module to obtain a spatially distributed multi-range interference pattern, which is the multi-range measurement signal; S5: based on the multi-range interference pattern obtained in step S4, obtain the intensity amplitude characteristic information value and the phase characteristic information value, and complete the characteristic test analysis of the object to be measured.

15. The method of claim 14, wherein the step of measuring the optical fiber device property is performed by a plurality of times. Between step S2 and step S3, further comprising: according to the existing parameters of the to-be-tested object, the performance estimation obtained in step S1, and the connection point quantity and the connection loss estimation of the to-be-tested object after accessing the multi-span measurement device in step S2, adjusting the signal light power in the measurement arm and the reference arm of the multi-span test system.

16. The method of claim 14, wherein the step of measuring the optical fiber device property is performed by a plurality of times. In step S5, further comprising: according to the spatial corresponding positions of the measurement signal and the reference background signal in step S3, obtaining the corresponding relationship of the measurement signal and the reference background signal under different spans, dividing the intensity amplitude and the phase characteristics under different spans to eliminate the coefficients, and cooperating with the supplementary spectrum test to perfect the calibration.

17. The method of claim 14, wherein the step of measuring the optical fiber device property is performed by a plurality of times. The method further comprises: S6: comparing the characteristic information value obtained in step S5 with the estimation value in step S1, and comparing the background interference information value magnitude of the reference background signal in step S3, to judge whether the interface connection mode of the to-be-tested object accessing the multi-span measurement device needs to be adjusted: if adjustment is needed, repeating the operation of step S2 and adjusting the interface connection mode, and then repeating steps S3-S5 to complete the characteristic test analysis of the to-be-tested object; if adjustment is not needed, directly completing the characteristic test analysis of the to-be-tested object.

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