技术领域technical field
本发明属于光纤传感技术领域，具体涉及一种基于移相信号调制的光纤光栅传感调制解调方法及装置。The invention belongs to the technical field of optical fiber sensing, and in particular relates to a fiber grating sensing modulation and demodulation method and device based on phase-shift signal modulation.
背景技术Background technique
随着科学技术的迅猛发展，人类社会已步入高速发展的信息时代。物联网技术、通信技术以及计算机已成为飞速发展的信息技术。在此基础上，物联网中的传感网络越来越受到人们的密切关注。在信息技术的发展过程中，各个行业都离不开传感器，比如工业控制、自动化生产过程、环境监测、石油管道的监测、生物医学、安防监测、桥梁和隧道监测等等都有传感器的踪迹。和传统的电子传感器相比，光纤光栅传感器光纤传感器具有尺寸小，重量轻，成本低廉，抗电磁干扰，灵敏度高，安全可靠，耐腐蚀，可进行分布式测量，易于组网等诸多优点，已经广泛应用于对温度，振动，应力等参量的测量。With the rapid development of science and technology, human society has entered the information age of rapid development. Internet of things technology, communication technology and computer have become information technology with rapid development. On this basis, the sensor network in the Internet of Things has received more and more close attention. In the development of information technology, various industries are inseparable from sensors, such as industrial control, automated production process, environmental monitoring, oil pipeline monitoring, biomedicine, security monitoring, bridge and tunnel monitoring, etc. There are traces of sensors. Compared with traditional electronic sensors, fiber optic sensors have many advantages such as small size, light weight, low cost, anti-electromagnetic interference, high sensitivity, safety and reliability, corrosion resistance, distributed measurement, and easy networking. Widely used in the measurement of temperature, vibration, stress and other parameters.
美国专利US5903350(Demodulator and Method useful for MultiplexedOptical Sensors)，提出了“五步调制法”，需要在一个调制脉冲内，产生5个相位变化，分别为0，π/2，π，3π/2，2π。这种调制解调方法，需要产生5个台阶状的调制信号，5个相位需要均匀的提高，每个相位台阶宽度相等。该调制解调方法对产生调制信号所用的硬件及方法具有很高要求，由于相位调制的激光脉冲光束宽度较小，在生成5个相同宽度的相位台阶时，其高度不易保持均匀提高且单个相位容易产生抖动。该调制解调方法还需要双脉冲光束，利用一个经过“五步调制法”的脉冲光束和另一个未进过调制的脉冲光束发生干涉，从而提供干涉光强信号。所以在脉冲光束进入光纤光栅组之前需要通过补偿器，以使两个脉冲光束获得相应的时间差，使两个脉冲光束从光纤光栅组返回后可以发生干涉。但由于补偿器的精度问题，两个脉冲光束干涉时可能产生误差，降低最终探测精度。US Patent US5903350 (Demodulator and Method useful for Multiplexed Optical Sensors) proposes a "five-step modulation method", which needs to generate 5 phase changes within one modulation pulse, which are 0, π/2, π, 3π/2, 2π . This modulation and demodulation method needs to generate 5 step-shaped modulation signals, and 5 phases need to be improved uniformly, and the step width of each phase is equal. This modulation and demodulation method has very high requirements on the hardware and methods used to generate the modulation signal. Since the beam width of the phase-modulated laser pulse is small, when five phase steps of the same width are generated, its height is not easy to maintain a uniform increase and a single phase It is prone to jitter. The modulation and demodulation method also requires dual pulse beams, using a "five-step modulation" pulse beam to interfere with another pulse beam that has not been modulated to provide an interference light intensity signal. Therefore, before the pulse beam enters the fiber Bragg grating group, it needs to pass through the compensator, so that the two pulse beams can obtain a corresponding time difference, so that the two pulse beams can interfere after returning from the fiber Bragg grating group. However, due to the accuracy of the compensator, errors may occur when the two pulsed beams interfere, reducing the final detection accuracy.
发明内容Contents of the invention
本发明的目的在于提供一种基于移相信号调制的光纤光栅传感调制解调方法及装置，解决了传统相位检测技术调制难度大、易受干扰、硬件系统要求高、解算速度慢，多区域探测时硬件复杂的问题。The purpose of the present invention is to provide a fiber grating sensing modulation and demodulation method and device based on phase-shift signal modulation, which solves the problems of traditional phase detection technology, which is difficult to modulate, susceptible to interference, high hardware system requirements, slow solution speed, and many problems. Hardware complex issues in area detection.
实现本发明目的的技术解决方案为：一种基于移相信号调制的光纤光栅传感调制解调方法，方法步骤如下：The technical solution to realize the purpose of the present invention is: a fiber grating sensing modulation and demodulation method based on phase-shift signal modulation, the method steps are as follows:
步骤1、打开激光光源，并使光纤光栅组感应振动，信号发生器分别与光开关和相位调制器连接，由信号发生器产生脉冲信号作用于光开关，产生连续光脉冲，作用于相位调制器，产生连续相位脉冲调制，激光光源发出的光依次经过隔离器、光开关和相位调制器，形成经相位调制的激光脉冲光束；Step 1. Turn on the laser light source and induce vibration of the fiber grating group. The signal generator is connected to the optical switch and the phase modulator respectively. The pulse signal generated by the signal generator acts on the optical switch to generate continuous optical pulses and acts on the phase modulator. , to generate continuous phase pulse modulation, the light emitted by the laser source passes through the isolator, optical switch and phase modulator in sequence to form a phase-modulated laser pulse beam;
步骤2、经过相位调制的激光脉冲光束进入环形器的第1端口，通过其第2端口进入熔接光纤光栅组的光纤，脉冲光束透过光纤光栅组中的不同光纤光栅时，均有部分脉冲光束返回环形器，相邻两个光纤光栅反射的脉冲光束在环形器中产生干涉信号，并从环形器的第3端口输出至光电转换器，光电转换器接收干涉信号，设相邻两个光纤光栅反射光的时间差为Δt，则相邻两个光纤光栅产生的干涉光强I(t)如下式：Step 2. The phase-modulated laser pulse beam enters the first port of the circulator, and enters the optical fiber of the fused fiber Bragg grating group through its second port. When the pulse beam passes through different fiber gratings in the fiber Bragg grating group, there are some pulse beams Returning to the circulator, the pulsed beams reflected by two adjacent fiber gratings generate an interference signal in the circulator, and output to the photoelectric converter from the third port of the circulator, and the photoelectric converter receives the interference signal, and two adjacent fiber gratings are set The time difference of reflected light is Δt, then the interference light intensity I(t) generated by two adjacent fiber gratings is as follows:
设振动信号的振动周期为TS，光开关形成的光脉冲光束宽度为T1，光开关形成的光脉冲周期与调制信号的相位调制周期相同，均为T，且T＜＜TS，所以认为在0＜t＜T这个时段内，振动信号在时域内保持不变；k为整数，令合相位其中为初始相，为漂移相，表示振动信号相；A、B均为常数；Assuming the vibration period of the vibration signal is TS , the width of the optical pulse beam formed by the optical switch is T1 , the optical pulse period formed by the optical switch is the same as the phase modulation period of the modulation signal, both are T, and T<<TS , so It is considered that within the period of 0<t<T, the vibration signal remains unchanged in the time domain; k is an integer, so that the phase in is the initial phase, is the drift phase, Indicates the vibration signal phase; A and B are constants;
步骤3、光电转换器将干涉信号转换为光强电信号，数据采集模块采集光强电信号，并将其送入数据处理模块，数据处理模块通过标定相位调制信号和接收信号的延时，获取相邻两个光纤光栅发生干涉后产生的三路移相的光强信号I1，I2，I3，于是有Step 3. The photoelectric converter converts the interference signal into an electrical signal of light intensity. The data acquisition module collects the electrical signal of light intensity and sends it to the data processing module. The data processing module acquires The three phase-shifted light intensity signals I1 , I2 , and I3 generated after two adjacent fiber gratings interfere, so there is
根据三步移相算法，解得According to the three-step phase-shifting algorithm, the solution
步骤4、去除θ的初始直流相和漂移相，解调出连续的振动信号相Step 4. Remove the initial DC phase and drift phase of θ, and demodulate the continuous vibration signal phase
一种基于移相信号调制的光纤光栅传感调制解调方法的装置，包括激光光源、隔离器、光开关、相位调制器、环形器、光纤光栅组、信号发生器、光电转换器、数据采集模块和数据处理模块，其中激光光源、隔离器、光开关、相位调制器和环形器依次连接，光纤光栅组与光纤熔接，环形器的第2端口与熔接光纤光栅组的光纤连接，信号发生器分别与光开关和相位调制器连接，环形器的第3端口通过光纤与光电转换器连接，数据采集模块分别与光电转换器和数据处理模块连接。A fiber grating sensing modulation and demodulation device based on phase-shift signal modulation, including laser light source, isolator, optical switch, phase modulator, circulator, fiber grating group, signal generator, photoelectric converter, data acquisition module and data processing module, in which the laser light source, isolator, optical switch, phase modulator and circulator are connected in sequence, the fiber grating group is fused with the fiber, the second port of the circulator is connected with the fiber of the fused fiber grating group, and the signal generator They are respectively connected to the optical switch and the phase modulator, the third port of the circulator is connected to the photoelectric converter through an optical fiber, and the data acquisition module is connected to the photoelectric converter and the data processing module respectively.
所述激光光源发出的光依次经过隔离器、光开关和相位调制器，信号发生器产生脉冲信号作用于光开关，使光开关对激光进行调制，生成光脉冲并送入相位调制器，同时信号发生器产生高速脉冲信号，向相位调制器提供π/2的相位调制，使激光脉冲光束通过相位调制器形成经相位调制的激光脉冲光束；经过相位调制的激光脉冲光束进入环形器的第1端口，通过其第2端口进入熔接光纤光栅组的光纤，经光纤光栅组反射后，返回环形器，在环形器中产生干涉信号，并从环形器的第3端口输出至光电转换器，光电转换器将干涉信号转换为光强电信号，数据采集模块采集光强电信号，并将其送入数据处理模块，解调出连续的振动信号相The light emitted by the laser light source passes through the isolator, optical switch and phase modulator in sequence, and the signal generator generates a pulse signal to act on the optical switch, so that the optical switch modulates the laser, generates optical pulses and sends them to the phase modulator, and simultaneously the signal The generator generates a high-speed pulse signal, and provides π/2 phase modulation to the phase modulator, so that the laser pulse beam passes through the phase modulator to form a phase-modulated laser pulse beam; the phase-modulated laser pulse beam enters the first port of the circulator , the fiber that enters the fusion-spliced fiber grating group through its second port, returns to the circulator after being reflected by the fiber grating group, generates an interference signal in the circulator, and outputs it to the photoelectric converter from the third port of the circulator, the photoelectric converter The interference signal is converted into a light intensity electrical signal, and the data acquisition module collects the light intensity electrical signal and sends it to the data processing module to demodulate the continuous vibration signal phase
本发明与现有技术相比，其显著优点在于：(1)利用光开关产生激光脉冲，利用相位调制器对激光脉冲光束进行相位内调制，利用光纤光栅对特定波长光束反射及环形器单向环形传输的特型，在环形器中实现多路移相信号的产生，有利于快速解算相位信息。Compared with the prior art, the present invention has significant advantages in that: (1) the optical switch is used to generate laser pulses, the phase modulator is used to modulate the laser pulse beam in phase, and the optical fiber grating is used to reflect specific wavelength beams and the circulator is one-way The special type of ring transmission realizes the generation of multiple phase-shifted signals in the circulator, which is beneficial to quickly solve the phase information.
(2)结构简单，尺寸小，精度高，信噪比高，抗环境干扰能力强，对调制信号的要求低，提高了算法的实时性。(2) The structure is simple, the size is small, the accuracy is high, the signal-to-noise ratio is high, the ability to resist environmental interference is strong, the requirement for the modulation signal is low, and the real-time performance of the algorithm is improved.
(3)可根据需求调节光纤光栅数量和间隔从而调整探测范围及探测区域数量。(3) The number and interval of fiber gratings can be adjusted according to the requirements, so as to adjust the detection range and the number of detection areas.
附图说明Description of drawings
图1为本发明的基于移相信号调制的光纤光栅传感调制解调方法的装置结构示意图。Fig. 1 is a schematic diagram of the device structure of the fiber grating sensing modulation and demodulation method based on phase-shift signal modulation according to the present invention.
图2为本发明单独两个光纤光栅(6-1、6-2)构成传感模块时反射光信号图，其中(a)、(b)为反射光脉冲中相位和时间关系图，(c)为环形器5第3端口(5-3)输出的光强和时间关系图，时间轴上大矩形代表反射光脉冲，之上的小矩形代表相位信息。Fig. 2 is the reflected light signal diagram when two fiber gratings (6-1, 6-2) of the present invention constitute the sensing module alone, wherein (a), (b) are phase and time relationship diagrams in the reflected light pulse, (c ) is the light intensity and time relationship graph output by the third port (5-3) of the circulator 5, the large rectangle on the time axis represents the reflected light pulse, and the small rectangle above represents the phase information.
图3为本发明四个光纤光栅(6-1、6-2、6-3、6-4)构成传感模块时反射光信号图，其中(a)、(b)、(c)、(d)为单个反射光脉冲中相位和时间关系图，(e)为环形器5第3端口输出的光强和时间关系图，时间轴上大矩形代表反射光脉冲，其上的小矩形代表相位信息。Fig. 3 is the reflected light signal diagram when four fiber gratings (6-1, 6-2, 6-3, 6-4) of the present invention constitute the sensing module, wherein (a), (b), (c), ( d) is the phase and time relationship diagram in a single reflected light pulse, (e) is the light intensity and time relationship diagram output by the third port of the circulator 5, the large rectangle on the time axis represents the reflected light pulse, and the small rectangle on it represents the phase information.
图4为本发明实施例中解调出的振动信号相信息。Fig. 4 is the demodulated vibration signal phase in the embodiment of the present invention information.
具体实施方式detailed description
下面结合附图对本发明作进一步详细描述。The present invention will be described in further detail below in conjunction with the accompanying drawings.
结合图1，一种基于移相信号调制的光纤光栅传感调制解调方法，方法步骤如下：In conjunction with Figure 1, a fiber grating sensing modulation and demodulation method based on phase-shift signal modulation, the steps of the method are as follows:
步骤1、打开激光光源1，让测试人员在熔接了光纤光栅组6的光纤附近走动，使得光纤光栅组6感应振动，信号发生器7分别与光开关3和相位调制器4连接，由信号发生器7产生脉冲信号作用于光开关3，产生连续激光脉冲，作用于相位调制器4，产生相位为π/2的连续相位脉冲调制，激光光源1发出的光依次经过隔离器2、光开关3和相位调制器4，形成经相位调制的激光脉冲光束。Step 1. Turn on the laser light source 1, and let the tester walk around the optical fiber to which the fiber grating group 6 is fused, so that the fiber grating group 6 is induced to vibrate, and the signal generator 7 is connected to the optical switch 3 and the phase modulator 4 respectively, and the signal generator 7 The pulse signal generated by the device 7 acts on the optical switch 3 to generate continuous laser pulses, which acts on the phase modulator 4 to generate continuous phase pulse modulation with a phase of π/2. The light emitted by the laser light source 1 passes through the isolator 2 and the optical switch 3 in sequence and a phase modulator 4 to form a phase-modulated laser pulse beam.
经相位调制的激光脉冲光束，其脉冲光束宽度T1由相邻两光纤光栅间距决定，为一个脉冲内，激光光束可以表示为For the phase-modulated laser pulse beam, the pulse beam width T1 is determined by the distance between two adjacent fiber gratings, which is Within one pulse, the laser beam can be expressed as
式中E0表示激光光源1的功率振幅，v0表示激光光源1的中心频率，t表示传播时间，表示经高速脉冲调制的相位，产生π/2的相位调制，其一个周期内调制的脉冲宽度为τns。In the formula, E0 represents the power amplitude of the laser light source 1, v0 represents the center frequency of the laser light source 1, t represents the propagation time, Indicates the phase modulated by the high-speed pulse, which produces a phase modulation of π/2, and the modulated pulse width in one cycle is τns.
步骤2、经过相位调制的激光脉冲光束进入环形器5的第1端口，通过其第2端口进入熔接光纤光栅组6的光纤，脉冲光束经过光纤光栅组6反射后，返回环形器5，在环形器5中产生干涉信号，并从环形器5的第3端口输出至光电转换器8，光电转换器8接收干涉信号，设相邻两个光纤光栅间距为ΔL，光束到达相邻两个光纤光栅并返回的时间分别为t1、t2，则反射光存在时间差ΔtStep 2. The phase-modulated laser pulse beam enters the first port of the circulator 5, and enters the optical fiber of the fused fiber Bragg grating group 6 through its second port. The interference signal is generated in the device 5, and is output from the third port of the circulator 5 to the photoelectric converter 8, and the photoelectric converter 8 receives the interference signal, and the distance between two adjacent fiber gratings is ΔL, and the light beam reaches the adjacent two fiber gratings and return times are t1 and t2 respectively, then there is a time difference Δt in the reflected light
其中n表示介质折射率，C表示激光在真空中的传播速度。Among them, n represents the refractive index of the medium, and C represents the propagation speed of the laser in vacuum.
光电转换器8接收到的干涉光强I(t1，Δt)可以表示为The interference light intensity I(t1 , Δt) received by the photoelectric converter 8 can be expressed as
其中A，B均为常数，且有B＝KA，K＜1，K为干涉条纹可见度，为初始相，为漂移相，表示振动信号相，为调制相。Among them, A and B are constants, and B=KA, K<1, K is the visibility of interference fringes, is the initial phase, is the drift phase, Indicates the vibration signal phase, for the modulation phase.
是由高速脉冲信号产生的π/2相位调制，其具体表达式为 It is a π/2 phase modulation generated by a high-speed pulse signal, and its specific expression is
其中k为整数，T表示脉冲信号的周期。in k is an integer, and T represents the period of the pulse signal.
当有外界振动时，振动引起的等效的光纤长度的变化与相邻两个光纤光栅间初始长度差相比可以忽略，即Δt的变化可以忽略，控制脉冲信号的占空比，使得令合相位则干涉光强I(t)可等效为下式When there is external vibration, the change of the equivalent fiber length caused by the vibration can be ignored compared with the initial length difference between two adjacent fiber gratings, that is, the change of Δt can be ignored, and the duty cycle of the pulse signal is controlled so that Aspect Then the interference light intensity I(t) can be equivalent to the following formula
设振动信号的振动周期为TS，脉冲调制信号的周期T＜＜TS，所以认为在0＜t＜T这个时段内，振动信号在时域内保持不变。Assuming that the vibration period of the vibration signal is TS , and the period of the pulse modulation signal is T<<TS , it is considered that the vibration signal remains unchanged in the time domain during the period of 0<t<T.
步骤3、光电转换器8将干涉信号转换为光强电信号，数据采集模块9采集光强电信号，并将其送入数据处理模块10，数据处理模块10通过标定相位调制信号和接收信号的延时，来获取三路移相的干涉光强信号I1，I2，I3，于是有Step 3, the photoelectric converter 8 converts the interference signal into a light intensity electrical signal, and the data acquisition module 9 collects the light intensity electrical signal, and sends it to the data processing module 10, and the data processing module 10 calibrates the phase modulation signal and the received signal Delay, to obtain the three-way phase-shifted interference light intensity signal I1 , I2 , I3 , so there is
根据三步移相算法，解得According to the three-step phase-shifting algorithm, the solution
步骤4、去除θ的初始直流相和漂移相，解调出连续的振动信号相Step 4. Remove the initial DC phase and drift phase of θ, and demodulate the continuous vibration signal phase
结合图1，一种基于移相信号调制的光纤光栅传感调制解调方法的装置，包括激光光源1、隔离器2、光开关3、相位调制器4和环形器5、光纤光栅组6、信号发生器7、光电转换器8、数据采集模块9和数据处理模块10，其中激光光源1、隔离器2、光开关3、相位调制器4和环形器5通过光纤依次连接，光纤光栅组6与光纤熔接，熔接光纤光栅组6的光纤与环形器5的第2端口连接，信号发生器7分别与光开关3和相位调制器4连接，环形器5的第3端口通过光纤与光电转换器8连接，数据采集模块9分别与光电转换器8和数据处理模块10连接。In conjunction with FIG. 1 , a device based on a phase shift signal modulation fiber Bragg grating sensing modulation and demodulation method, including a laser light source 1, an isolator 2, an optical switch 3, a phase modulator 4 and a circulator 5, a fiber Bragg grating group 6, Signal generator 7, photoelectric converter 8, data acquisition module 9 and data processing module 10, wherein laser light source 1, isolator 2, optical switch 3, phase modulator 4 and circulator 5 are connected sequentially through optical fibers, fiber grating group 6 Fused with optical fiber, the optical fiber of the fused fiber grating group 6 is connected to the second port of the circulator 5, the signal generator 7 is respectively connected to the optical switch 3 and the phase modulator 4, and the third port of the circulator 5 is connected to the photoelectric converter through the optical fiber 8, the data acquisition module 9 is connected to the photoelectric converter 8 and the data processing module 10 respectively.
所述激光光源1发出的光依次经过隔离器2、光开关3、和相位调制器4，信号发生器7分别与光开关3和相位调制器4连接，由信号发生器7产生脉冲信号作用于光开关3，产生连续激光脉冲，作用于相位调制器4，产生相位为π/2的连续相位脉冲调制；经过相位调制的激光脉冲光束进入环形器5的第1端口，通过第2端口进入熔接光纤光栅组6的光纤，经光纤光栅组6反射后，返回环形器5，在环形器5中产生干涉信号，并从环形器5的第3端口输出至光电转换器8，光电转换器8将干涉信号转换为光强电信号，数据采集模块9采集光强电信号，并将其送入数据处理模块10，解调出连续的振动信号相The light emitted by the laser light source 1 passes through the isolator 2, the optical switch 3, and the phase modulator 4 in sequence, and the signal generator 7 is connected with the optical switch 3 and the phase modulator 4 respectively, and the pulse signal generated by the signal generator 7 acts on the The optical switch 3 generates continuous laser pulses, which act on the phase modulator 4 to generate continuous phase pulse modulation with a phase of π/2; the phase-modulated laser pulse beam enters the first port of the circulator 5, and enters the fusion through the second port The optical fiber of the fiber grating group 6 returns to the circulator 5 after being reflected by the fiber grating group 6, and an interference signal is generated in the circulator 5, and is output to the photoelectric converter 8 from the 3rd port of the circulator 5, and the photoelectric converter 8 will The interference signal is converted into a light intensity electric signal, and the data acquisition module 9 collects the light intensity electric signal, and sends it to the data processing module 10, and demodulates the continuous vibration signal phase
所述环形器5采用三个端口的环形器，光纤光栅组6采用光纤布拉格光栅。The circulator 5 is a circulator with three ports, and the fiber grating group 6 is a fiber Bragg grating.
所述数据处理模块10通过三步移相算法，得到合相位θ，并去除θ的初始直流相和漂移相，解调出连续的振动信号相The data processing module 10 obtains the combined phase θ through a three-step phase-shifting algorithm, removes the initial DC phase and drift phase of θ, and demodulates the continuous vibration signal phase
实施例1Example 1
实验测试了某光纤光栅传感器的振动信息，两光栅光纤间距为24m，采样时间为22s，激光脉冲周期和相位调制脉冲的频率为1MHz，一个周期内相位调制的脉冲宽度为160ns，其测量装置如图1所示，其测量步骤为：The vibration information of a fiber grating sensor is tested in experiments. The distance between the two grating fibers is 24m, the sampling time is 22s, the laser pulse cycle and the frequency of the phase modulation pulse are 1MHz, and the pulse width of the phase modulation in one cycle is 160ns. The measuring device is as follows: As shown in Figure 1, the measurement steps are:
步骤1、打开激光光源1并让测试人员在熔接了光纤光栅组6的光纤附近走动，使得光纤光栅组6感应振动，激光光源1发出的光依次经过隔离器2、光开关3和相位调制器4，信号发生器7产生频率为1MHz的高速脉冲信号，其作用于光开关3，产生连续激光脉冲，同时向相位调制器4提供π/2的相位调制，形成经相位调制的激光脉冲光束；Step 1. Turn on the laser light source 1 and let the tester walk around the optical fiber to which the fiber grating group 6 is fused, so that the fiber grating group 6 is induced to vibrate, and the light emitted by the laser light source 1 passes through the isolator 2, the optical switch 3 and the phase modulator in sequence 4. The signal generator 7 generates a high-speed pulse signal with a frequency of 1 MHz, which acts on the optical switch 3 to generate continuous laser pulses, and simultaneously provides a phase modulation of π/2 to the phase modulator 4 to form a phase-modulated laser pulse beam;
步骤2、经过相位调制的激光脉冲光束进入环形器5第1端口，通过第2端口进入熔接光纤光栅组6的光纤，经光纤光栅组6反射后，在环形器5中产生干涉信号，光电转换器8接收干涉信号。Step 2. The phase-modulated laser pulse beam enters the first port of the circulator 5, and enters the optical fiber of the fused fiber Bragg grating group 6 through the second port. After being reflected by the fiber Bragg grating group 6, an interference signal is generated in the circulator 5, and photoelectric conversion is performed. The device 8 receives the interference signal.
步骤3、数据采集模块9采集由光电转换器8产生的光强电信号，并将其送入数据处理模块10，数据处理模块10通过标定相位调制信号和接收信号的延时，来获取三路移相的干涉光强信号。Step 3, the data acquisition module 9 collects the light intensity electrical signal generated by the photoelectric converter 8, and sends it to the data processing module 10, and the data processing module 10 obtains the three-way signal by calibrating the delay of the phase modulation signal and the received signal Phase-shifted interferometric light intensity signal.
步骤4、去除θ的初始直流相和漂移相，解调出连续的振动信号相Step 4. Remove the initial DC phase and drift phase of θ, and demodulate the continuous vibration signal phase
结合图2～图4，本实施例通过一系列的措施实现了对相位振动信号的测量。最终求得的相位图，波动较大处为测试员跨过光纤时产生，其数量、幅度与测试员实际走动情况吻合，反映出该光纤光栅传感器准确的探测出工作范围内的振动信号变化，表明该方法简单实用，测量精度较高，抗干扰能力强，实时性高。With reference to FIGS. 2 to 4 , this embodiment realizes the measurement of the phase vibration signal through a series of measures. In the finally obtained phase diagram, the larger fluctuations are generated when the tester crosses the optical fiber, and the number and amplitude are consistent with the actual movement of the tester, reflecting that the fiber grating sensor can accurately detect the vibration signal changes within the working range. It shows that the method is simple and practical, with high measurement accuracy, strong anti-interference ability and high real-time performance.
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| CN201610204797.6ACN107290042B (en) | 2016-04-05 | 2016-04-05 | Fiber Bragg Grating Sensing Modulation and Demodulation Method and Device Based on Phase Shift Signal Modulation |
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