WO2021212687A1 - 一种基于sagnac原理实现差分平衡探测的超声测量装置 - Google Patents

一种基于sagnac原理实现差分平衡探测的超声测量装置 Download PDF

Info

Publication number
WO2021212687A1
WO2021212687A1 PCT/CN2020/106206 CN2020106206W WO2021212687A1 WO 2021212687 A1 WO2021212687 A1 WO 2021212687A1 CN 2020106206 W CN2020106206 W CN 2020106206W WO 2021212687 A1 WO2021212687 A1 WO 2021212687A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
polarization
coupler
polarized
ultrasonic
Prior art date
Application number
PCT/CN2020/106206
Other languages
English (en)
French (fr)
Inventor
王自鑫
蔡志岗
赵伟鸿
王福娟
王嘉辉
李佼洋
黄柱源
张锡斌
李文哲
Original Assignee
中山大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中山大学 filed Critical 中山大学
Publication of WO2021212687A1 publication Critical patent/WO2021212687A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/58—Turn-sensitive devices without moving masses
    • G01C19/64—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
    • G01C19/72—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
    • G01C19/725—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers using nxn optical couplers, e.g. 3x3 couplers

Definitions

  • the invention belongs to the technical field of optical fiber gyroscopes, and particularly relates to an ultrasonic measuring device that realizes differential balance detection based on the SAGNAC principle.
  • the traditional ultrasonic generation and reception method is to use an ultrasonic ring energy device, such as piezoelectric transducer, CMUT transducer, these methods are all contact measurement methods.
  • traditional contact transducers are increasingly being replaced by non-contact optical methods, including interferometry and beam deflection methods.
  • Optical fiber sensor is a new type of ultrasonic sensing device. It is widely used because of its small size, light weight, strong environmental adaptability, strong reliability, easy detection signal transmission, and good confidentiality.
  • optical fiber sensors there are relatively few researches on the use of optical fiber sensors in ultrasonic testing, especially non-contact testing, especially in domestic research.
  • the combination of optical fiber sensing technology and non-contact ultrasonic testing technology will have broad prospects in the application of ultrasonic testing and flaw detection of materials.
  • the purpose of the present invention is to provide an ultrasonic measuring device based on SAGNAC principle to realize differential balance detection, which adopts the basic principle of SAGNAC interferometer, the vibration of the sample surface will bring about the change of optical path difference, using CW light and CCW light successively
  • the interference signal formed by the change of the optical path difference caused by the time of reaching the sample surface is used for the ultrasonic detection of the sample surface.
  • the core of the present invention is to use two polarization controllers and a polarization beam splitter to realize the modulation of the pi/2 initial phase and the orthogonal polarization state of the interference light to form a differential interference signal to enter the balanced detector to improve the detection sensitivity.
  • the details are as follows:
  • An ultrasonic measuring device for realizing differential balanced detection based on the SAGNAC principle which is characterized by comprising a light source, a first polarization controller, a second polarization controller, a first non-polarized 1*2 coupler, and a second non-polarized 1*2 Coupler, sample probe, circulator, polarization beam splitter, balanced detector;
  • the light source, the first polarization controller, and the circulator are connected in sequence, one port of the circulator is connected to the polarization beam splitter and the balanced detector in sequence, and the other port is connected to the first non-polarized 1*2 coupler, One output port of the first non-polarized 1*2 coupler is connected to the second non-polarized 1*2 coupler through a long fiber loop, and the other output port is connected to the second non-polarized 1*2 coupler through a second polarization controller , The output end of the second non-polarized 1*2 coupler is connected with the sample probe.
  • a further improvement is that the light from the light source first passes through the first polarization controller and the circulator, and then passes through the first non-polarized 1*2 coupler into two paths with different lengths, one of which is along the The CW light in the clockwise direction, and the other way is the CCW light in the counterclockwise direction.
  • a further improvement is that the light source adopts a broad-spectrum SLED light source with low coherence.
  • a further improvement is that the CW light and CCW light pass through the second non-polarized 1*2 coupler and the sample probe to reach the ultrasonic sample, and the reflected light enters the sample probe again and returns to the optical fiber optical path.
  • a further improvement is that the return light of the CW light and the CCW light enters the circulator again after passing through the first non-polarized 1*2 coupler, so as to realize the isolation of the incident light and the return light.
  • a further improvement is that the interference light with the initial phase of pi/2 and the orthogonal polarization state passes through the polarization beam splitter to form two differential interference signals with equal intensity and enter the balanced detector.
  • a further improvement is that all optical fibers and optical fiber components except for the polarization beam splitter are non-polarized.
  • a further improvement is that the sample probe adopts a collimator and lens structure to focus the sample, so that the optical signal carrying ultrasonic information on the surface of the sample returns to the optical fiber optical path.
  • a further improvement is that the polarization beam splitter uses three optical fibers with polarization maintaining interfaces.
  • a further improvement is that the specific process of modulating the interfering light forming the initial phase of pi/2 and the orthogonal polarization state is: by adjusting the first and second polarization controllers to realize the initial phase difference and the non-polarization plane of the CW light and the CCW light. Independent control, realize the working state of pi/2 initial phase and polarization plane orthogonal.
  • the beneficial effects of the present invention are: all the optical fiber components used in the present invention are non-polarized except for the polarization beam splitter, which reduces the cost; compared with the traditional method of pi/2 phase bias through a phase modulator , The solution of the present invention is more convenient, and the control effect is good; compared with the traditional use of polarization maintaining fiber to maintain the orthogonality or parallelism of the interference light, the solution of the present invention also achieves the same effect by using two polarization controllers, and is easy Adjustment; Compared with single-ended signal detection, the method for detecting differential interference signals with a balanced detector according to the present invention has better detection sensitivity.
  • Figure 1 is a system diagram of the entire optical fiber optical path of the device
  • Figure 2 is a partial schematic diagram of the loop of the device
  • Figure 3 is an analysis diagram when the optical path difference of CW light and CCW light is within half the wavelength range
  • Figure 4 is an analysis diagram of the frequency selection effect of the interference system
  • Figure 5 is an analysis diagram of the interference signal being divided into two channels after passing through the polarization beam splitter
  • Figure 6 shows that the stress principal axis of the polarization-maintaining fiber and the xy coordinate axes formed by the o-light and e-light of the PBS crystal coincide.
  • the angle of polarization is 45° or 135°;
  • An ultrasonic measuring device for realizing differential balanced detection based on the SAGNAC principle which is characterized by comprising a light source, a first polarization controller, a second polarization controller, a first non-polarized 1*2 coupler, and a second non-polarized 1*2 Coupler, sample probe, circulator, polarization beam splitter, balanced detector;
  • the light source, the first polarization controller, and the circulator are connected in sequence, one port of the circulator is connected to the polarization beam splitter and the balanced detector in sequence, and the other port is connected to the first non-polarized 1*2 coupler, One output port of the first non-polarized 1*2 coupler is connected to the second non-polarized 1*2 coupler through a long fiber loop, and the other output port is connected to the second non-polarized 1*2 coupler through a second polarization controller , The output end of the second non-polarized 1*2 coupler is connected with the sample probe.
  • the light from the light source first passes through the first polarization controller and the circulator, and then passes through the first non-polarized
  • the 1*2 coupler is divided into two paths with different lengths, one of which is CW light in the clockwise direction, and the other is CCW light in the counterclockwise direction.
  • the light source adopts a broad-spectrum SLED light source with low coherence.
  • the CW light and the CCW light pass through the second non-polarized 1*2 coupler and the sample probe to reach the ultrasonic sample.
  • the returned light enters the sample probe again and returns to the optical path of the optical fiber.
  • the return light of the CW light and the CCW light enters the circulator again after passing through the first non-polarized 1*2 coupler , To achieve the isolation of incident light and return light.
  • the interfering light of the initial phase of pi/2 and the orthogonal polarization state forms two beams of equal intensity after passing through the polarization beam splitter.
  • the differential interference signal enters the balanced detector.
  • the ultrasonic measurement device for realizing differential balanced detection based on the SAGNAC principle of the present invention all the optical fibers and optical fiber components except for the polarization beam splitter are non-polarized.
  • the sample probe adopts a collimator and lens structure to focus the sample, so that the optical signal carrying ultrasonic information on the surface of the sample returns to the optical fiber optical path.
  • the polarization beam splitter adopts three optical fibers with polarization maintaining interfaces.
  • the specific process of modulating the interference light with the initial phase of pi/2 and the orthogonal polarization state is: by adjusting the first and second
  • the polarization controller realizes the non-independent adjustment of the initial phase difference and polarization plane of CW light and CCW light, and realizes the working state where the initial phase of pi/2 and the polarization plane are orthogonal.
  • the light source of the system uses a 1550nm SLED broadband low-coherent light source to avoid interference from coherent noise.
  • the light from the light source first passes through the first polarization controller PC1, and then passes through the first non-polarized 1*2 coupler BS1. Assuming that the CW light goes through the top one in Figure 1 first, then the CW light will pass through a long optical fiber in turn.
  • the second non-polarized 1*2 coupler BS2 the sample probe, and then return to the second non-polarized 1*2 coupler BS2, and then go the next way, enter the circulator through the first non-polarized 1*2 coupler BS1, CCW light
  • the beamer PBS is then decomposed into two differential interference signals with phase differences of ⁇ pi/2 respectively.
  • the specific adjustment process is: by adjusting the first and second polarization controllers, the initial phase difference and the polarization plane of the CW light and the CCW light are not independently adjusted, and the initial phase of pi/2 and the polarization plane are orthogonal to the working state. If the polarization beam splitter PBS is not added at this time, the interference efficiency is almost zero. Since the polarization directions are orthogonal, after adding the polarization beam splitter PBS, adjust the angle of the slow axis of the input end of the polarization beam splitter PBS so that the fast and slow axis of the input end of the polarization beam splitter PBS and the polarization directions of the CW light and CCW light are respectively 45° (135°) included angle, as shown in Figure 6. At this time, the original non-interference has become two differential interference signals with the highest interference efficiency.
  • ⁇ is the wavelength
  • c is the speed of light
  • Is the phase difference
  • ⁇ L is the length difference between the long and short arms of the fiber
  • ⁇ is the delay of the long and short arms
  • An appropriate operating point should have the maximum sensitivity when the system has zero signal, that is, when the sample is free of vibration.
  • the derivative of this point is 0, which means it works at the least sensitive position. The place.
  • an initial phase difference should be given when no signal occurs in the sample
  • the essence of the SAGNAC interferometer is a velocity interferometer, which is to differentiate the oscillation.
  • the interference signal is also a sinusoidal signal, and the signal strength is the largest at this time;
  • the beam of light (CCW) arrives at time t2

Abstract

一种基于SAGNAC原理实现差分平衡探测的超声测量装置，包括光源、第一偏振控制器、第二偏振控制器、第一非偏振1*2耦合器、第二非偏振1*2耦合器、样品探头、环形器、偏振分束器、平衡探测器；光源出来的光首先经过第一偏振控制器和环形器，经过第一非偏振耦合器分成长度不同的两路，其中一路为沿顺时针方向的CW光，另外一路为沿逆时针方向的CCW光；通过控制两个偏振控制器和偏振分束器慢轴夹角，实现干涉光的pi/2初相位和正交偏振态的调制和形成两束强度相等的差分干涉信号，由平衡探测器实现差分干涉信号的平衡探测；与现有技术相比，该装置利用SAGNAC效应实现非接触式超声检测方法具有结构简单、成本低、体积小、灵敏度高的特点，应用范围广泛。

Description

一种基于SAGNAC原理实现差分平衡探测的超声测量装置 技术领域
本发明属于光纤陀螺技术领域，尤其涉及一种基于SAGNAC原理实现差分平衡探测的超声测量装置。
技术背景
声波与物质相互作用时，声速及声波的能量会发生变化，通过对声速和声波衰减的测量，可以确定物质的一些基本物理参数。这就是超声检测技术，它是研究物质结构及其特性的基本方法之一，在许多领域已获得成功应用。传统的超声产生和接收方法是使用超声环能器，如压电换能器、CMUT换能器，这些方法都是接触式的测量方法。当前，传统的接触式换能器越来越多的被非接触的光学方法代替，包括了干涉法和光束偏转法等。由于光学技术的不断提高，这方面的研究也在飞速发展，并不断产生新的探测技术，包括光纤传感技术。光纤传感器是一种新兴的超声传感器件，因为具有体积小、重量轻、环境适应性强、可靠性强、检测信号传输容易、保密性好等许多优点而得到广泛应用。但是将光纤传感器用于超声检测，尤其是非接触式检测的研究还相对较少，尤其是国内研究很少。将光纤传感技术与非接触式超声检测技术相结合，在材料的超声检测、探伤应用方面将具有广阔的前景。
发明内容
本发明的目的是提供一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其采用了SAGNAC干涉仪的基本原理，样品表面的振动会带来光程差的变化，利用CW光和CCW光先后到达样品表面的时间不同引起光程差变化形成的干涉信号进行样品表面超声波的检测。本发明的核心在于利用两个偏振控制器和一个偏振分束器实现干涉光的pi/2初相位和正交偏振态的调制形成差分干涉信号进入平衡探测器从而提高探测灵敏度，具体内容如下：
一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于，包括光源、第一偏振控制器、第二偏振控制器、第一非偏振1*2耦合器、第二非偏振1*2耦合器、样品探头、环形器、偏振分束器、平衡探测器；
通过控制所述第一偏振控制器、第二偏振控制器，调制形成pi/2初相位和正交偏振态的干涉光；
所述光源、第一偏振控制器、环形器依次相连，所述环形器的其中一个端口与偏振分束器、平衡探测器依次相连，另外一个端口与第一非偏振1*2耦合器相连，第一非偏振1*2耦合器的一个输出端口通过长光纤环与第二非偏振1*2耦合器相连，另外一个输出端口通过第二偏振控制器与第二非偏振1*2耦合器相连，第二非偏振1*2耦合器的输出端与所述样品探头相连。
进一步的改进在于，所述光源出来的光首先经过所述第一偏振控制器和所述环形器，然后经过所述第一非偏振1*2耦合器分成长度不同的两路，其中一路为沿顺时针方向的CW光，另外一路为沿逆时针 方向的CCW光。
进一步的改进在于，所述光源采用具有低相干的宽谱SLED光源。
进一步的改进在于，所述CW光和CCW光经过所述第二非偏振1*2耦合器和所述样品探头到达超声样品，反回光再次进入样品探头返回光纤光路。
进一步的改进在于，所述CW光和CCW光的返回光再次经过所述第一非偏振1*2耦合器后进入所述环形器，实现入射光和返回光的隔离。
进一步的改进在于，所述pi/2初相位和正交偏振态的干涉光经过所述偏振分束器后形成两束强度相等的差分干涉信号进入所述平衡探测器。
进一步的改进在于，除所述偏振分束器以外其它所有的光纤和光纤器件都是采用非偏振式的。
进一步的改进在于，所述样品探头采用准直器加透镜的结构聚焦样品，实现携带样品表面超声信息的光信号返回光纤光路。
进一步的改进在于，所述偏振分束器采用的是三个带保偏接口的光纤。
进一步的改进在于，调制形成pi/2初相位和正交偏振态的干涉光的具体过程为：通过调节第一和第二偏振控制器实现CW光和CCW光的初始相位差和偏振面的非独立调控，实现pi/2的初始相位和偏振面正交的工作状态。
本发明的有益效果为：本发明所采用的所有光纤器件除了偏振分束器以外全部采用非偏振式的，降低了成本；相比于传统的通过相位调制器进行pi/2相位偏置的方法，本发明的方案更加方便，且控制效果好；相比于传统的利用保偏光纤保持干涉光的正交或平行，本发明的方案采用两个偏振控制器也实现了同样的效果，且容易调节；相比于单端信号检测，本发明所述的用平衡探测器探测差分干涉信号的方法，具有更好的探测灵敏度。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为所述装置的整个光纤光路系统图；
图2为所述装置的环路部分示意图；
图3为当CW光和CCW光的光程差在半个波长范围以内的分析图；
图4为干涉系统的频率选择效应分析图；
图5为干涉信号经过偏振分束器之后被分成两路的分析图；
图6为保偏光纤的应力主轴和PBS晶体的o光、e光所形成的xy坐标轴是重合的，旋转保偏光纤端口的慢轴夹角，使得快、慢轴和两个正交的偏振方向成45°或135°的夹角图；
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于，包括光源、第一偏振控制器、第二偏振控制器、第一非偏振1*2耦合器、第二非偏振1*2耦合器、样品探头、环形器、偏振分束器、平衡探测器；
通过控制所述第一偏振控制器、第二偏振控制器，调制形成pi/2初相位和正交偏振态的干涉光；
所述光源、第一偏振控制器、环形器依次相连，所述环形器的其中一个端口与偏振分束器、平衡探测器依次相连，另外一个端口与第一非偏振1*2耦合器相连，第一非偏振1*2耦合器的一个输出端口通过长光纤环与第二非偏振1*2耦合器相连，另外一个输出端口通过第二偏振控制器与第二非偏振1*2耦合器相连，第二非偏振1*2耦合器的输出端与所述样品探头相连。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述光源出来的光首先经过所述第一偏振控制器和所述环形器，然后经过所述第一非偏振1*2耦合器分成长度不同的两路，其中一路为沿顺时针方向的CW光，另外一路为沿逆时针方向的CCW光。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述光源采用具有低相干的宽谱SLED光源。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述CW光和CCW光经过所述第二非偏振1*2耦合器和所述样品探头到达超声样品，反回光再次进入样品探头返回光纤光路。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述CW光和CCW光的返回光再次经过所述第一非偏振1*2耦合器后进入所述环形器，实现入射光和返回光的隔离。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述pi/2初相位和正交偏振态的干涉光经过所述偏振分束器后形成两束强度相等的差分干涉信号进入所述平衡探测器。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，除所述偏振分束器以外其它所有的光纤和光纤器件都是采用非偏振式的。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述样品探头采用准直器加透镜的结构聚焦样品，实现携带样品表面超声信息的光信号返回光纤光路。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述偏振分束器采用的是三个带保偏接口的光纤。
在本发明所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置中，所述调制形成pi/2初相位和正交偏振态的干涉光的具 体过程为：通过调节第一和第二偏振控制器实现CW光和CCW光的初始相位差和偏振面的非独立调控，实现pi/2的初始相位和偏振面正交的工作状态。
如图1所示，系统的光源采用1550nm SLED宽带低相干光源，以避免相干噪声的干扰。光源出来的光首先经过第一偏振控制器PC1，然后经过第一非偏振1*2耦合器BS1，设CW光先走的是图1中的上面一路，那么CW光会依次经过一段长光纤，第二非偏振1*2耦合器BS2，样品探头，然后再返回第二非偏振1*2耦合器BS2，之后走下面一路，经过第一非偏振1*2耦合器BS1进入环形器，CCW光也是类似的情况：先走下面的光路，返回的时候走上面的光路，如图2所示。
如图5所示，由于CW光和CCW光走的大部分光路都是完全一样的，只有在经过第二偏振控制器PC2的时候CW光和CCW光会由于双折射效应导致经过第二偏振控制器PC2时，CW光和CCW光偏振面的改变不一样，附加的光程也不一样。利用CW光和CCW光附加的光程差不一样，调节第二偏振控制器PC2使得初始相位差为pi/2。此时CW光和CCW光的偏振面也发生了旋转，调节第一偏振控制器PC1和偏振分束器PBS的慢轴夹角，使得CW光和CCW光处于正交偏振的状态，经过偏振分束器PBS以后被分解成相位差分别为±pi/2的两路差分干涉信号。
具体的调节过程是：通过调节第一和第二偏振控制器实现CW光和CCW光的初始相位差和偏振面的非独立调控，实现pi/2的初始相位和偏振面正交的工作状态。此时若不加偏振分束器PBS，则干涉效 率几乎为0。由于偏振方向正交，加入偏振分束器PBS之后，调节偏振分束器PBS输入端慢轴的夹角使得偏振分束器PBS输入端的快慢轴和CW光、CCW光的偏振方向分别成45°(135°)的夹角，如图6所示。此时由原来的不干涉变成了干涉效率最大的两路差分干涉信号。
本发明的原理如下：其中，λ为波长，c为光的波速，
Figure PCTCN2020106206-appb-000001
为相位差，ΔL为光纤的长短臂长度差，Δτ为长短臂的延时；
考虑样品的振荡：
Figure PCTCN2020106206-appb-000002
SAGNAC干涉仪长短臂的延时：
Figure PCTCN2020106206-appb-000003
延时对应的光程差：
Figure PCTCN2020106206-appb-000004
最大灵敏度条件：
一个合适的工作点，应该在系统零信号时，也就是样品无振动时具有最大的灵敏度。在样品无信号时，由于两路光光程差相同，Δφ＝0，此时系统工作在干涉极大的位置，根据余弦函数的性质，该点的导数为0，也就是工作在最不灵敏的地方。为了提高静态工作点的灵敏度，在样品无信号发生的时候应该给予一个初始的相位差
Figure PCTCN2020106206-appb-000005
相位连续条件：如图3所示：
若考虑非线性的情况，则只需要让ω AΔτ工作在半个波长以内的范围，从而避免相位折叠的现象。但是由于非线性会造成信号失真，因此需要对测量的信号经过一个逆运算才能复原出样品的振荡信号。
保证相位连续的条件是：
Figure PCTCN2020106206-appb-000006
SAGNAC干涉仪的频率选择效应：
从前面的推导可看出，SAGNAC干涉仪的本质是一个速度干涉仪，也就是对振荡求微分。微分器具有低通滤波的效应，但是实际上的SAGNAC干涉系统不是一个严格的微分器，由于系统的灵敏度有限，两束光到达样品表面的时间差不可能做的无限小。这种非理想的微分效应，导致SAGNAC干涉仪会出现一个频率选择效应，在某些频率最敏感，而在另一些频率最不敏感。如图4所描述的情况中，当Δτ＝π/ω A时,干涉仪最敏感；当Δτ＝2π/ω A时，干涉仪最不敏感。当第一束光(CCW光)在t1时刻到达，第二束光(CW光)经过Δτ＝π/ω A后到达时，干涉信号也是个正弦信号，此时信号的强度最大；当第一束光(CCW)在t2时刻到达，第二束光(CW)在Δτ＝2π/ω A后到达时，此时无信号，相当于ω A/2的信号被滤掉了。
需要说明的是，在本文中，诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来，而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是 还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。
尽管已经示出和描述了本发明的实施例，对于本领域的普通技术人员而言，可以理解在不脱离本发明的原理和精神的情况下可以对这些实施例进行多种变化、修改、替换和变型，本发明的范围由所附权利要求及其等同物限定。

Claims (10)

  1. 一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于，包括光源、第一偏振控制器、第二偏振控制器、第一非偏振1*2耦合器、第二非偏振1*2耦合器、样品探头、环形器、偏振分束器、平衡探测器；
    通过控制所述第一偏振控制器、第二偏振控制器，调制形成pi/2初相位和正交偏振态的干涉光；
    所述光源、第一偏振控制器、环形器依次相连，所述环形器的其中一个端口与偏振分束器、平衡探测器依次相连，另外一个端口与第一非偏振1*2耦合器相连，第一非偏振1*2耦合器的一个输出端口通过长光纤环与第二非偏振1*2耦合器相连，另外一个输出端口通过第二偏振控制器与第二非偏振1*2耦合器相连，第二非偏振1*2耦合器的输出端与所述样品探头相连。
  2. 根据权利要求1所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于：所述光源出来的光首先经过所述第一偏振控制器和所述环形器，然后经过所述第一非偏振1*2耦合器分成长度不同的两路，其中一路为沿顺时针方向的CW光，另外一路为沿逆时针方向的CCW光。
  3. 根据权利要求1所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于所述光源采用具有低相干的宽谱SLED光源。
  4. 根据权利要求2所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于所述CW光和CCW光经过所述第二非 偏振1*2耦合器和所述样品探头到达超声样品，反回光再次进入样品探头返回光纤光路。
  5. 根据权利要求4所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于所述CW光和CCW光的返回光再次经过所述第一非偏振1*2耦合器后进入所述环形器，实现入射光和返回光的隔离。
  6. 根据权利要求1所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于所述pi/2初相位和正交偏振态的干涉光经过所述偏振分束器后形成两束强度相等的差分干涉信号进入所述平衡探测器。
  7. 根据权利要求1所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于除所述偏振分束器以外其它所有的光纤和光纤器件都是采用非偏振式的。
  8. 根据权利要求1所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于所述样品探头采用准直器加透镜的结构聚焦样品，实现携带样品表面超声信息的光信号返回光纤光路。
  9. 根据权利要求1所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于所述偏振分束器采用的是三个带保偏接口的光纤。
  10. 根据权利要求2所述的一种基于SAGNAC原理实现差分平衡探测的超声测量装置，其特征在于调制形成pi/2初相位和正交偏振态的干涉光的具体过程为：通过调节第一和第二偏振控制器实现CW光 和CCW光的初始相位差和偏振面的非独立调控，实现pi/2的初始相位和偏振面正交的工作状态。
PCT/CN2020/106206 2020-04-24 2020-07-31 一种基于sagnac原理实现差分平衡探测的超声测量装置 WO2021212687A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010333900.3A CN111337009B (zh) 2020-04-24 2020-04-24 一种基于sagnac原理实现差分平衡探测的超声测量装置
CN202010333900.3 2020-04-24

Publications (1)

Publication Number Publication Date
WO2021212687A1 true WO2021212687A1 (zh) 2021-10-28

Family

ID=71184803

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/106206 WO2021212687A1 (zh) 2020-04-24 2020-07-31 一种基于sagnac原理实现差分平衡探测的超声测量装置

Country Status (2)

Country Link
CN (1) CN111337009B (zh)
WO (1) WO2021212687A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115166062A (zh) * 2022-08-22 2022-10-11 天津大学 一种基于差分干涉的全光学超声探测器及探测方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111337009B (zh) * 2020-04-24 2022-02-01 中山大学 一种基于sagnac原理实现差分平衡探测的超声测量装置
CN113048968B (zh) * 2020-11-11 2022-08-19 中山大学 非保偏型Sagnac干涉仪的偏振态控制系统及方法
CN114353778B (zh) * 2021-05-17 2022-11-29 中山大学 在非保偏的Sagnac型干涉仪中实现π/2初始相位锁定的方法及装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102221397A (zh) * 2011-04-06 2011-10-19 天津大学 基于Sagnac干涉仪的LSAW定位测量系统
US10323925B2 (en) * 2015-10-23 2019-06-18 University Of Washington Compact portable double differential fiber optic Sagnac interferometer
CN111337009A (zh) * 2020-04-24 2020-06-26 中山大学 一种基于sagnac原理实现差分平衡探测的超声测量装置

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102809421A (zh) * 2011-06-01 2012-12-05 电子科技大学 基于偏振态差分探测可多点定位的分布式光纤振动传感器
CN103344646B (zh) * 2013-06-25 2015-07-22 中国人民解放军陆军军官学院 基于光学相干层析技术实时检测聚变堆第一壁损伤的方法
CN103424344B (zh) * 2013-08-25 2015-05-06 浙江大学 基于双波长光纤干涉法探测纳米微粒尺度的方法及装置
CN107091877A (zh) * 2017-04-26 2017-08-25 桂林电子科技大学 激光注入光纤与相干探测的激光超声无损检测方法
CN108168728B (zh) * 2017-12-11 2019-12-10 哈尔滨工程大学 非平衡保偏光纤双干涉仪温度应变同时测量装置及方法
CN109946048A (zh) * 2019-04-02 2019-06-28 南京聚科光电技术有限公司 一种任意波长激光相频噪声测试装置及方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102221397A (zh) * 2011-04-06 2011-10-19 天津大学 基于Sagnac干涉仪的LSAW定位测量系统
US10323925B2 (en) * 2015-10-23 2019-06-18 University Of Washington Compact portable double differential fiber optic Sagnac interferometer
CN111337009A (zh) * 2020-04-24 2020-06-26 中山大学 一种基于sagnac原理实现差分平衡探测的超声测量装置

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
JANG, T.S. ; LEE, S.S. ; KIM, Y.G.: "Surface-bonded fiber optic Sagnac sensors for ultrasound detection", ULTRASONICS, vol. 42, no. 1-9, 1 April 2004 (2004-04-01), GB , pages 837 - 841, XP027331454, ISSN: 0041-624X *
LIANG, YIJUN ET AL.: "Optical Fiber Sagnac Interferometeric Sensor for Measurement of Feeble Vibration", JOURNAL OF HARBIN ENGINEERING UNIVERSITY, vol. 28, no. 1, 15 January 2007 (2007-01-15), pages 118 - 122, XP055861366, ISSN: 1006-7043 *
TAE SEONG JANG ; SEUNG SEOK LEE ; IL BUM KWON ; WANG JOO LEE ; JUNG JU LEE: "Noncontact detection of ultrasonic waves using fiber optic Sagnac interferometer", IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL, IEEE, USA, vol. 49, no. 6, 1 June 2002 (2002-06-01), USA, pages 767 - 775, XP011438428, ISSN: 0885-3010, DOI: 10.1109/TUFFC.2002.1009334 *
YAN, WEI: "Research on Fiber-Optic Sensor Using Laser Ultrasonic Testing", DOCTORAL DISSERTATIONS AND MASTER THESES, 15 December 2004 (2004-12-15), CN, pages 1 - 52, XP009531430 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115166062A (zh) * 2022-08-22 2022-10-11 天津大学 一种基于差分干涉的全光学超声探测器及探测方法

Also Published As

Publication number Publication date
CN111337009A (zh) 2020-06-26
CN111337009B (zh) 2022-02-01

Similar Documents

Publication Publication Date Title
WO2021212687A1 (zh) 一种基于sagnac原理实现差分平衡探测的超声测量装置
WO2021017098A1 (zh) 差动式正弦相位调制激光干涉纳米位移测量装置及方法
US5894531A (en) Method and apparatus for detection of ultrasound using a fiber-optic interferometer
WO2019062466A1 (zh) 正弦相位调制干涉仪pgc解调实时归一化修正装置及方法
CN107664482B (zh) 光栅测量装置
WO2019210734A1 (zh) 一种基于平面镜反射的激光外差干涉测量装置和方法
KR101978444B1 (ko) 편광 빛살 가르게를 이용한 광섬유 사냑 간섭계
WO2019024753A1 (zh) 一种互易型差动式调频连续波干涉保偏光纤陀螺仪
WO2021212688A1 (zh) 一种基于sagnac原理实现光程和偏振态调控的超声测量装置
US8842291B2 (en) Interferometric quasi-autocollimator
CN107664481A (zh) 光栅测量装置
CN111735391A (zh) 双相位测量式激光干涉直线度及位移同时测量装置和方法
KR101981707B1 (ko) 편광 빛살가르게를 이용한 자유공간 사냑 간섭계
Chen et al. A heterodyne straightness and displacement measuring interferometer with laser beam drift compensation for long-travel linear stage metrology
JPH03180704A (ja) レーザ干渉計
CN113514046B (zh) 基于马赫曾德干涉的原子自旋进动信号检测装置及方法
CN117394909B (zh) 一种量子态编解码模块的编解码误差测量装置及方法
US5351124A (en) Birefringent component axis alignment detector
CN106813901B (zh) 光学器件相位延迟量的测量装置及其测量方法
CN105823995A (zh) 一种平面任意方向磁场光纤传感器
TW201425869A (zh) 光學干涉裝置
JPS60243509A (ja) 干渉計
Lou et al. A phase modulating homodyne interferometer with tilting error compensation by use of an integrated four-photodetector
Wang et al. Modified homodyne laser interferometer based on phase modulation for simultaneously measuring displacement and angle
Xu et al. Full path compensation laser feedback interferometry for remote sensing with recovered nanometer resolutions

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20931846

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205 DATED 24-02-2023)

122 Ep: pct application non-entry in european phase

Ref document number: 20931846

Country of ref document: EP

Kind code of ref document: A1