CN103616570A - Self-correcting optoelectronic integration electric field sensor system - Google Patents

Abstract

The invention relates to a self-correcting optoelectronic integration electric field sensor system, and belongs to the technical field of electric field measurement. The output end of a laser source is connected with the input end of a sensor sequentially through a polarizer and an input polarization maintaining optical fiber, and the output end of the sensor is connected with the input end of a detector sequentially through an output polarization maintaining optical fiber, a polarization beam splitter and a Y-waveguide modulator. Electric signals output by the detector pass through the processor to generate control signals of an adjustable direct current power module and generates the signals of an electric field to be detected backwards through arithmetical operation of the processor, the adjustable direct current power module is controlled to provide voltage signals for the Y-waveguide modulator, and closed-loop control is formed. The self-correcting optoelectronic integration electric field sensor system achieves field calibration of a system transfer function through the feedback control of the Y-waveguide modulator, and improves measurement accuracy. The quiescent operating point of the system is adjusted to pi/2, and the sensor is made to work in the best state.

Description

A kind of self-correcting photoelectric integration electric-field sensor system

Technical field

The present invention relates to a kind of self-correcting photoelectric integration electric-field sensor system, belong to electric field measurement technical field.

Background technology

Electric field measurement is significant in many scientific researches and field of engineering technology, particularly in fields such as electric system, electromagnetic compatibility and microwave technologies, has a wide range of applications.

Along with developing rapidly of integrated optics technique, photoelectric integration electric-field sensor has obtained more and more many research and application.The existing electric field measurement system based on photoelectric integrated sensor, as application number is: 201310076620.9, the be as the criterion patented claim of reciprocity digital closed loop lithium niobate fiber waveguide alternating electric field/voltage sensor of denomination of invention, containing antenna, measures sensitivity lower on its lithium niobate straight wave guide sensing unit; And the all-digital closed-loop system that has adopted optical fibre gyro, system response time is longer, measure comparatively difficulty of electromagnetic compatibility and microwave technical field transient-wave, so its application is confined to power frequency highfield or voltage measurement in electric system.Application number is: 201210348311.8, denomination of invention is a kind of patented claim of the integrated electric field sensor based on common path interference, its structure as shown in Figure 1,

Wherein A is the photoelectric conversion factors that has reflected luminous power, optical path loss and the detector of lasing light emitter output; B is the extinction ratio of sensor, depends on the coupling technique of optical waveguide in polarization maintaining optical fibre and sensor; for the quiescent bias point of sensor, depend on the physical dimension of optical waveguide; E _πfor half-wave electric field, depend on the physical dimension of lithium columbate crystal in sensor, antenna and modulator electrode; E is electric field signal to be measured, and V is the voltage signal of detector output.

Consider the environmental factors such as temperature, humidity can cause A, b,

the change in various degree of three parameters, for guaranteeing to measure accurately, is preferably in and measures before electric field signal, and three parameters are demarcated.It is auxiliary that in prior art, the staking-out work of sensor needs the equipment such as voltage source of parallel-plate electrode and high voltage amplitude (conventionally more than 10kV), is difficult to realize in measure field, and its range of application is restricted in laboratory environment.

In addition, quiescent bias point

to sensor can survey scope have material impact, as shown in Figure 2.When

or during π, the quiescent point of transport function is positioned at the top of cosine function, belongs to zone of saturation, greatly reduce on the one hand the sensitivity of measuring, be that serious distortion occurs measured waveform on the other hand, by the anti-electric field signal that pushes away of voltage signal, encounter difficulties; When

quiescent point is positioned at the approximately linear section of cosine function, and measuring system has maximum sensitivity and the input-output characteristic of approximately linear.Sensor quiescent bias point in prior art

lack FEEDBACK CONTROL, once the environment factors such as temperature change, cause change, sensor quiescent operation is named a person for a particular job and is departed from cosine function linearity range, and measuring system loses maximum sensitivity and the input-output characteristic of approximately linear.

In sum, this prior art is mainly deposited defect both ways: one, and transducer calibration work is difficult to realize in measure field, and range of application is restricted in laboratory environment; On the other hand, the quiescent bias point of sensor

lack FEEDBACK CONTROL, once the environment factors such as temperature change, cause

change, sensor quiescent operation is named a person for a particular job and is departed from cosine function linearity range, and measuring system loses the input and output transfer function characteristics of maximum sensitivity and approximately linear.

Summary of the invention

The object of the invention is to propose a kind of self-correcting photoelectric integration electric-field sensor system, utilize the FEEDBACK CONTROL of Y waveguide modulator, realize the on-site proving of A, two parameters of b, realize Measurement accuracy; And quiescent bias point is adjusted to

make sensor possess optimum performance.

The self-correcting photoelectric integration electric-field sensor system that the present invention proposes, comprising:

Lasing light emitter, for sending laser;

The polarizer, changes into linearly polarized light for the laser that lasing light emitter is sent, and plays show off device and is connected by single-mode fiber with lasing light emitter;

Sensor, for receiving linearly polarized light by input polarization maintaining optical fibre, the polarization axle of input polarization maintaining optical fibre is coupled to axle with sensor with 45 °, and linearly polarized light Orthogonal Decomposition is the linearly polarized light of the luminous power different polarization patterns such as two bundles, in the optical waveguide of sensor, propagates; Antenna induction Y-direction electric field signal to be measured in sensor, produce a potential difference (PD), this potential difference (PD) by the modulator electrode on sensor to the light signal generating modulating action of propagating in optical waveguide, make the propagation constant of the linearly polarized light of two bundle different polarization patterns that complementary variation occur, the linearly polarized light of two bundle different polarization patterns produces the phase differential corresponding with electric field signal intensity to be measured at the exit end of optical waveguide;

Polarization beam apparatus, for receive the linearly polarized light of the dephased two bundle different polarization patterns of tool by output polarization maintaining optical fibre, and make the linearly polarized light of the two bundle different polarization patterns propagated in polarization maintaining optical fibre same output separated, obtain the linearly polarized light that two bundles are independently propagated;

Y waveguide modulator, for receive the independent linearly polarized light of propagating of two bundles by two polarization maintaining optical fibres, and proofread and correct the independently phase differential of the linearly polarized light of propagation of two bundles according to the voltage modulation signal from adjustable DC module, two bunch polarized lights after phase calibration is poor interfere at the Y of Y waveguide modulator branch's intersection point place, obtain the light signal after a beam interferometer, Y waveguide modulator is connected with polarization beam apparatus by two polarization maintaining optical fibres, by cable, is connected with adjustable DC power module;

Detector, for receive the light signal after interfering by single-mode fiber, converts light signal to voltage signal;

Processor, for the voltage signal of exporting by cable pick-up probe, obtains electric field signal to be measured according to transport function and the calibrated parameter mathematical operation thereof of storage, simultaneously for adjustable DC power module provides control signal.

Adjustable DC power module, for the control signal of exporting by cable receiving processor, produces a voltage modulation signal according to this control signal, and this voltage modulation signal is sent to Y waveguide modulator.

The self-correcting photoelectric integration electric-field sensor system that the present invention proposes, its advantage is: before measurement, realize the on-site proving of each parameter of transport function, thereby realize the accurate measurement of electric field signal; By Y waveguide modulator, to pi/2, sensor is worked in the best condition the quiescent operation point calibration of photoelectric integration electric-field sensor system, thereby greatly improved the electric field measurement sensitivity of electric-field sensor system of the present invention.

Accompanying drawing explanation

Fig. 1 is the structural representation of photoelectric integration electric-field measuring system in prior art.

Fig. 2 is the principle schematic of quiescent point on the impact of electric field measurement system transport function.

Fig. 3 is the structural representation of the self-correcting photoelectric integration electric-field sensor system that proposes of the present invention.

In Fig. 1 and Fig. 3, the 1st, lasing light emitter, the 2nd, the polarizer, the 3rd, sensor, the 4th, optical waveguide, the 5th, antenna, the 6th, modulator electrode, the 7th, lithium niobate (LiNbO ₃) wafer, the 8th, analyzer, the 9th, detector, the 10th, polarization beam apparatus, the 11st, Y waveguide modulator, the 12nd, processor, the 13rd, adjustable DC power module.

Embodiment

The self-correcting photoelectric integration electric-field sensor system that the present invention proposes, its structure as shown in Figure 3, comprising:

Lasing light emitter 1, for sending laser;

The polarizer 2, changes into linearly polarized light for the laser that lasing light emitter is sent, and plays show off device and is connected by single-mode fiber with lasing light emitter;

Sensor 3, for receiving linearly polarized light by input polarization maintaining optical fibre, the polarization axle of input polarization maintaining optical fibre is coupled to axle with sensor with 45 °, linearly polarized light Orthogonal Decomposition is the linearly polarized light of the luminous power different polarization patterns (two kinds of patterns of transverse electric wave and transverse magnetic wave) such as two bundles, in the optical waveguide 4 of sensor, propagates; Antenna induction Y-direction electric field signal to be measured in sensor, produce a potential difference (PD), this potential difference (PD) by the modulator electrode on sensor to the light signal generating modulating action of propagating in optical waveguide, make the propagation constant of the linearly polarized light of two bundle different polarization patterns that complementary variation occur, the linearly polarized light of two bundle different polarization patterns produces the phase differential corresponding with electric field signal intensity to be measured at the exit end of optical waveguide;

Polarization beam apparatus 10, for receive the linearly polarized light of the dephased two bundle different polarization patterns of tool by output polarization maintaining optical fibre, and make the linearly polarized light of the two bundle different polarization patterns propagated in polarization maintaining optical fibre same output separated, obtain the linearly polarized light that two bundles are independently propagated;

Y waveguide modulator 11, for receive the independent linearly polarized light of propagating of two bundles by two polarization maintaining optical fibres, and proofread and correct the independently phase differential of the linearly polarized light of propagation of two bundles according to the voltage modulation signal from adjustable DC power module, two bunch polarized lights after phase calibration is poor interfere at the Y of Y waveguide modulator branch's intersection point place, obtain the light signal after a beam interferometer, Y waveguide modulator is connected with polarization beam apparatus by two polarization maintaining optical fibres, by cable, is connected with adjustable DC power module;

Detector 9, for receive the light signal after interfering by single-mode fiber, converts light signal to voltage signal;

Processor 12, for the voltage signal of exporting by cable pick-up probe, obtains electric field signal to be measured according to transport function and the calibrated parameter mathematical operation thereof of storage, simultaneously for adjustable DC power module provides control signal.

Adjustable DC power module 13, for the control signal of exporting by cable receiving processor, produces a voltage modulation signal according to this control signal, and this voltage modulation signal is sent to Y waveguide modulator.

The self-correcting photoelectric integration electric-field sensor system that the present invention proposes, its principle of work is:

The partial poolarized light that lasing light emitter sends becomes linearly polarized light after the polarizer, the polarization axle of input polarization maintaining optical fibre is coupled to axle with sensor with 45 °, and linearly polarized light Orthogonal Decomposition is the linearly polarized light of the luminous power different polarization patterns (two kinds of patterns of transverse electric wave and transverse magnetic wave) such as two bundles, in the optical waveguide of sensor, propagates, antenna induction Y-direction electric field signal to be measured in sensor, produce a potential difference (PD), this potential difference (PD) by the modulator electrode on sensor to the light signal generating modulating action of propagating in optical waveguide, make the propagation constant of the linearly polarized light of two bundle different polarization patterns that complementary variation occur, the linearly polarized light of two bundle different polarization patterns produces the phase differential corresponding with electric field signal intensity to be measured at the exit end of optical waveguide, output polarization maintaining optical fibre polarization axle is coupled to axle with sensor with 0 °, and the linearly polarized light with the pairwise orthogonal polarization mode of certain phase differential is propagated along the fast and slow axis of polarization maintaining optical fibre respectively, two bunch polarized lights in fast and slow axis are separately propagated after polarization beam apparatus beam splitting in the slow axis of two polarization maintaining optical fibres, rear two arms of simultaneously injecting Y waveguide modulator, Y waveguide modulator is proofreaied and correct the phase differential of the two bunch polarized lights of propagating at Y waveguide two arms according to the voltage modulation signal from adjustable DC power module, two bunch polarized lights after phase calibration is poor interfere at the intersection point place of the Y of Y waveguide modulator branch, the interference signal generating imports photo-detector into and carries out opto-electronic conversion, the electric signal input processor of conversion performs mathematical calculations, processor is according to control signal and the electric field signal to be measured of this electric signal output adjustable DC power module, adjustable DC power module provides modulation signal according to the control letter of processor output for Y waveguide modulator.

Before use sensing system of the present invention carries out electric field measurement, first carry out demarcation and the correction of measuring system itself, so that measuring system is worked in the best condition, guarantee measurement precision and the stability of measuring system.

Scaling method is:

If the transport function of sensing system is as shown in Equation 2:

Wherein A is the photoelectric conversion factors that has reflected luminous power, optical path loss and the detector of lasing light emitter output; B is the extinction ratio of sensor, depends on the coupling technique of optical waveguide in polarization maintaining optical fibre and sensor;

for the quiescent bias point of sensor, depend on the physical dimension of optical waveguide; E _πfor the half-wave electric field of sensor, depend on the physical dimension of lithium columbate crystal in sensor, antenna and modulator electrode; E is electric field signal to be measured, and V is the voltage signal of detector output,

for Y waveguide modulator is the additional biasing of sensor, can be expressed as following formula:

V wherein _πfor the half-wave voltage of Y waveguide modulator, depend on the physical dimension of lithium columbate crystal and modulator electrode in Y waveguide modulator; V _infor being carried in the voltage signal on Y waveguide modulator by adjustable DC power module;

for Y waveguide modulator is the additional biasing of sensor.

Before measuring electric field signal, sensor is placed in to the environment (or by sensor wrap is createed in an airtight can to the environment of an E=0V/m by the method for shielding) of E=0V/m, now ssystem transfer function is as shown in Equation 4.The control signal of exporting by processor is controlled adjustable DC power module, makes the magnitude of voltage of adjustable DC power module output at certain intervals from 0 to V _πchange, the magnitude of voltage of adjustable DC power module output offers Y waveguide modulator, makes

from 0 to V _πchange.During a magnitude of voltage of every change adjustable DC power module, by the output voltage V of detector under processor for recording, i.e. the output valve V of transport function.According to the feature of transport function (formula 4), can know,

from 0 to V _πduring change, detector output voltage V can obtain a maximal value V _maxwith a minimum value V _min, as shown in Equation 5, and by processor record.

$\left\{\begin{array}{c}{V}_{\max }=A\·(1+b)\\ V_{\min }=A\·(1-b)\end{array}\right.---\left(5\right)$

According to the V of processor for recording _maxand V _minby mathematical operation, obtain A value and the b value of transport function, as shown in Equation 6, and A value and b value are stored in processor, in order to after instead during electric field measurement release electric field value to be measured, realized the staking-out work of sensing system, calibration process need to be by the equipment such as voltage source of the necessary parallel-plate electrode of staking-out work in prior art and high voltage amplitude (conventionally more than 10kV).

$\left\{\begin{array}{c}A=[V_{\max }+V_{\min }]/2\\ b=[V_{\max }-V_{\min }]/[V_{\max }+V_{\min }]\end{array}\right.---\left(6\right)$

Bearing calibration is:

The control signal of exporting by processor is controlled adjustable DC power module, makes the magnitude of voltage of adjustable DC power module output at certain intervals from 0 to V _πchange, the magnitude of voltage of adjustable DC power module output offers Y waveguide modulator, makes

from 0 to V _πchange, also there is corresponding change in the output voltage V of detector.During a magnitude of voltage of every change adjustable DC power module, by the output voltage V of detector under processor for recording, and with processor in the magnitude of voltage V=A=[V that stores _max+ V _min]/2 compare, and when both are equal, stop changing the control signal of processor output, records and continue to export current control signal value.From transport function (formula 4), as the output valve V=A=[V of photo-detector _max+ V _min]/2, now

system transter can rewrite an accepted way of doing sth 7, and now measuring system is operated in optimum condition, has completed the correction work of sensing system.

$V=A\·[1+b\·\cos (\frac{E}{E_{\mathrm{\π}}}\mathrm{\π}+\frac{\mathrm{\π}}{2})]---\left(7\right)$

After the demarcation of sensing system and trimming process complete, sensor can be placed in and under electric field to be measured, carry out electric field measurement work.Electric field measurement method is:

The transport function of sensing system as shown in Equation 7, A, two parameters of b have been stored among processor, mathematical operation that can be by processor according to detector output valve V is anti-releases electric field value E to be measured.

In one embodiment of the present of invention, lasing light emitter 1 used adopts the lasing light emitter STL5411 of Sumimoto company; The structure of sensor 3 is: at lithium niobate (LiNbO ₃) wafer 7 upper surfaces adopt titanium method of diffusion to prepare optical waveguide 4, in the both sides of optical waveguide, adopt photoetching method to process antenna 5 and modulator electrode 6, wherein the length of lithium niobate crystal chip is 20mm, and width is 5mm, and thickness is 1mm; Detector 9 adopts the detector 1592 of NewFocus company; Y waveguide modulator 11 adopts the Y waveguide modulator GATV-15-10-0-A of Beijing Pu Dan photoelectricity technology corporation, Ltd.; The processor TMS320C6472 that processor 12 adopts Texas Instruments can realize the functions such as analog to digital conversion, comparer, mathematical operation simultaneously; Adjustable DC power module 13 adopts the adjustable DC power module LM4041-N-Q1 of Texas Instruments.

Claims (1)

1. a self-correcting photoelectric integration electric-field sensor system, comprising:

Lasing light emitter, for sending laser;

The polarizer, changes into linearly polarized light for the laser that lasing light emitter is sent, and plays show off device and is connected by single-mode fiber with lasing light emitter;

Sensor, for receiving linearly polarized light by input polarization maintaining optical fibre, the polarization axle of input polarization maintaining optical fibre is coupled to axle with sensor with 45 °, and linearly polarized light Orthogonal Decomposition is the linearly polarized light of the luminous power different polarization patterns such as two bundles, in the optical waveguide of sensor, propagates; Antenna induction Y-direction electric field signal to be measured in sensor, produce a potential difference (PD), this potential difference (PD) by the modulator electrode on sensor to the light signal generating modulating action of propagating in optical waveguide, make the propagation constant of the linearly polarized light of two bundle different polarization patterns that complementary variation occur, the linearly polarized light of two bundle different polarization patterns produces the phase differential corresponding with electric field signal intensity to be measured at the exit end of optical waveguide;

Characterized by further comprising:

Polarization beam apparatus, for receive the linearly polarized light of the dephased two bundle different polarization patterns of tool by output polarization maintaining optical fibre, and make the linearly polarized light of the two bundle different polarization patterns propagated in polarization maintaining optical fibre same output separated, obtain the linearly polarized light that two bundles are independently propagated;

Y waveguide modulator, for receive the independent linearly polarized light of propagating of two bundles by two polarization maintaining optical fibres, and proofread and correct the independently phase differential of the linearly polarized light of propagation of two bundles according to the voltage modulation signal from adjustable DC power module, two bunch polarized lights after phase calibration is poor interfere at the Y of Y waveguide modulator branch's intersection point place, obtain the light signal after a beam interferometer, Y waveguide modulator is connected with polarization beam apparatus by two polarization maintaining optical fibres, by cable, is connected with adjustable DC power module;

Detector, for receive the light signal after interfering by single-mode fiber, converts light signal to voltage signal;

Processor, for the voltage signal of exporting by cable pick-up probe, obtains electric field signal to be measured according to transport function and the calibrated parameter mathematical operation thereof of storage, simultaneously for adjustable DC power module provides control signal.

Adjustable DC power module, for the control signal of exporting by cable receiving processor, produces a voltage modulation signal according to this control signal, and this voltage modulation signal is sent to Y waveguide modulator.

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