CN111060896A - Large-range and high-precision absolute distance measuring instrument based on OEO (optical output interface) quick switching - Google Patents
Large-range and high-precision absolute distance measuring instrument based on OEO (optical output interface) quick switching Download PDFInfo
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- CN111060896A CN111060896A CN201911245313.2A CN201911245313A CN111060896A CN 111060896 A CN111060896 A CN 111060896A CN 201911245313 A CN201911245313 A CN 201911245313A CN 111060896 A CN111060896 A CN 111060896A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4817—Constructional features, e.g. arrangements of optical elements relating to scanning
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
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Abstract
The invention discloses an OEO (optical output interface) quick switching-based wide-range and high-precision absolute distance measuring instrument, which comprises an instrument internal delay module, a loop switching module and a frequency metering and distance calculating module, wherein the instrument internal delay module and the loop switching module are connected into a multi-cavity switching photoelectric oscillator structure through an optical fiber and a cable; and the instrument internal delay module is connected with the frequency measurement and distance calculation module. The invention applies the accumulation amplification principle to the measuring scheme of a large-range absolute distance length by utilizing OEO, can measure the absolute distance in a large range (km magnitude), and can achieve high measuring precision (mum magnitude); the distance measuring system is simple and easy to operate, can be widely applied to the fields of industrial measurement and control, precision instrument manufacturing and the like, and has good concealment and excellent application prospect in the military field due to strong anti-interference capability.
Description
Technical Field
The invention relates to an optical carrier microwave distance measuring system, in particular to a large-range and high-precision absolute distance measuring instrument based on OEO (optical output) quick switching.
Background
The development of the measurement technology is the premise and the basis of all scientific and technical development, the length is taken as one of 7 basic physical quantities, the length and the angle measurement form the basis of all geometric quantity measurement, and the development determines the capability of human beings to know the world and transform the world and is also a mark for measuring the technical level of measurement in one country.
Although the current method using laser interferometer can achieve the measurement accuracy of nm within several tens of meters, it can only measure the relative change of distance (also called relative distance measurement), so it requires a precise guide rail larger than the measured object, and the measurement and processing of the guide rail is a problem, and in many occasions, it is impossible to install the guide rail at all, and the measurement technology capable of directly measuring the distance between two points is very important, also called absolute distance measurement.
In recent years, with the development of science and technology, scientific research and production construction have brought more and more urgent demands on large-scale and high-precision distance measurement, such as: monitoring production, assembly and operation of large equipment and components; researching the earth gravitational field; the requirements of the fields of space exploration, navigation and the like in China.
The traditional laser ranging principle is divided into 3 types: the method comprises a pulse time-of-flight method, a phase method and an interference method, wherein the pulse time-of-flight method is the earliest application of laser in the field of ranging, the characteristics of extremely short duration and very large instantaneous power of laser pulse are utilized, the method has a very large testing range, but the testing precision and resolution are very low, and the development and application of the method are limited; the phase method laser ranging is to measure the distance of a measured target by using distance information contained in the phase difference between emitted modulated light and received light reflected by the measured target, wherein the measuring precision is influenced by the modulation frequency and the phase discrimination precision, a fuzzy distance exists, and a multi-frequency modulation method is needed to expand the measuring range; the interferometric distance measurement is a classical precise distance measurement method, which is also a phase method distance measurement in principle, but the distance measurement is performed by measuring the phase interference of the light wave instead of measuring the phase difference of the laser modulation signal, but the traditional interferometric method can only obtain the relative change of the distance during measurement, and cannot obtain the real distance information, and a method of measuring multiple wavelengths, namely a synthetic wavelength method or a frequency modulation light source method, is required in the wide-range absolute distance measurement.
Recently, the high-speed development of the femtosecond mode-locked laser provides more selection schemes for high-precision long-distance absolute distance measurement, and the measurement precision and the measurement range of the interferometric measurement technology can be improved by utilizing the unique advantages of the frequency comb in terms of line width and absolute frequency position, however, the method greatly depends on the stability of pulse repetition rate and the detection precision of pulse envelope phase.
At present, a method for measuring a large-distance high-precision absolute length mainly converts distance measurement into time measurement (a time-of-flight method) or phase measurement (a phase measurement method and an interferometry), obtains a more accurate measurement result by continuously improving measurement resolution, has higher requirement on the measurement resolution, has higher technical difficulty and has higher sensitivity to other interference factors.
In fact, there is an effective measurement method, by amplifying the measured signal and then measuring it, a very high accuracy measurement result can be obtained by a relatively low resolution measurement method, i.e. by accumulating the amplification principle, such as the classical pendulum period test, by the multi-period pendulum time test, even with a common stopwatch.
For the measurement of large distance and high precision absolute distance, the following ideas can be adopted: the measured distance forms a resonant cavity, and after resonance is formed, the cavity length (namely the measured length) determines the fundamental frequency f of the resonant cavitybAt this time, the detection accuracy of the fundamental frequency is the length measurement accuracy. Considering that the fundamental frequency is the inverse of the round-trip time of the signal in the cavity, this means that the fundamental frequency measurement is practically as difficult as the time-of-flight method, e.g. 1 μm accuracy over a length of 500m (fundamental frequency 300kHz) and 0.0006Hz for frequency detection accuracy. But when the cavity oscillates at higher harmonics, the actual resonant frequency fN＝N×fbThe variation of the fundamental frequency is amplified by a factor of N, again to an accuracy of 1 μm over a length of 500m, when tunedOscillation frequency at 30GHz (N10)5) The measurement accuracy of the frequency is only 60 Hz. To achieve the above assumption, there are two requirements for the resonant cavity:
1) since the measured distance constitutes a fraction of the cavity length, the cavity length is long enough for a large range measurement;
2) the high-order harmonic can be oscillated to ensure enough amplification factor;
optoelectronic oscillators (OEOs) are a new type of oscillator developed in recent years that requires a long resonant cavity to provide high stored energy; generally, the oscillation is carried out at a frequency of tens of GHz to dozens of GHz, the output spectrum purity is very high and can reach the mHz magnitude, and the two requirements are completely met.
In general, to determine the length of the distance to be measured, i.e. to determine f preciselyNAnd fbThe value of (a), the system is required to stabilize single-mode oscillation; because the OEO system adopts the optical fiber with a long length (usually in km magnitude) for energy storage, and the cavity length is easily influenced by the ambient temperature and stress to change, in order to ensure the accuracy of the measurement precision, the cavity length of the reference loop is usually controlled by adopting a method of controlling the piezoelectric ceramic optical fiber stretcher by using a phase-locked loop, the theoretical control precision of the cavity length needs to reach um magnitude, a plurality of piezoelectric ceramic optical fiber stretchers with different stretching amounts and precisions and a complex control algorithm are needed, and the complexity of the system is increased.
In addition, in order to ensure single-mode oscillation starting of the whole system, a system structure adopting a polarization double-ring or a wavelength double-ring is generally required to simulate a side mode, so that the cost and the complexity of the whole system are greatly increased.
In view of the above problems in the related art, no effective solution has been proposed at present.
Disclosure of Invention
Aiming at the technical problems in the related art, the invention provides the large-range and high-precision absolute distance measuring instrument based on OEO quick switching, which can measure the absolute distance in a large range and achieve high measuring precision.
In order to solve the technical problems, the large-range and high-precision absolute distance measuring instrument based on OEO quick switching comprises an instrument internal delay module, a loop switching module and a frequency metering and distance calculating module, wherein the instrument internal delay module and the loop switching module are connected into a multi-cavity switching photoelectric oscillator structure through optical fibers and cables; and the instrument internal delay module is connected with the frequency measurement and distance calculation module.
Further, the large-range and high-precision absolute distance measuring instrument based on OEO fast switching comprises an instrument internal delay module, a photoelectric detector, a microwave amplifier and an electric coupler, wherein the instrument internal delay module comprises n lasers, a first wavelength division multiplexer, a polarization controller, an electro-optical modulator, an optical circulator, an optical amplifier and a photoelectric detector; the first wavelength division multiplexer has n input ports and 1 output port; the n lasers are connected with n input ports of a first wavelength division multiplexer, an output port of the first wavelength division multiplexer is connected with a polarization controller, and the polarization controller is connected with an electro-optical modulator; the loop switching module comprises n reflectors, n collimators and a second wavelength division multiplexer; the n mirrors include 1 test mirror and n-1 measurement mirrors, the n collimators include 1 test collimator and n-1 measurement collimators, and the second wavelength division multiplexer has an input port and n output ports; the n collimators are connected with the n output ports of the second wavelength division multiplexer, the centers of the mirror surfaces of 1 test reflector of 1 test collimator correspond to the lens focuses of 1 test collimator, and the centers of the mirror surfaces of n-1 reflectors respectively correspond to the lens focuses of n-1 measurement collimators one by one; the electro-optical modulator is respectively connected with the input port of the second wavelength division multiplexer and the optical amplifier through the optical circulator; the optical amplifier is connected with the band-pass filter through the photoelectric detector, the band-pass filter is connected with the input port of the electric coupler through the microwave amplifier, the first output port of the electric coupler is connected with the radio frequency input port of the electro-optical modulator, and the second output port of the electric coupler is connected with the frequency metering and distance calculating module.
The optical circulator provided by the invention is provided with three ports which are respectively marked as a first port, a second port and a third port, wherein the first port is connected with the electro-optical modulator, the second port is connected with an input port of the second wavelength division multiplexer, and the third port is connected with the optical amplifier.
And the second port of the optical circulator is connected with the input port of the second wavelength division multiplexer, so that a multi-cavity switching photoelectric oscillator structure is formed.
In the invention, the type of the laser is a semiconductor laser or a fiber laser, and the n lasers are the same type of laser.
In the invention, the electro-optical modulator is one of a lithium niobate intensity modulator, a lithium niobate phase modulator and an electro-absorption modulator with a semiconductor structure.
In the invention, the optical amplifier is one of an erbium-doped optical fiber amplifier, an ytterbium-doped optical fiber amplifier, a thulium-doped optical fiber amplifier and a semiconductor optical amplifier.
Compared with the prior art, the invention has the beneficial effects that:
1) in the invention, the OEO is used for applying the accumulation amplification principle to the measurement of a large-range absolute distance length, and the characteristics of long OEO resonant cavity, high spectral purity and high resonant frequency are utilized to amplify the measured change by 105～106Therefore, the common measuring instrument can measure absolute distance in a large range (km magnitude) and achieve high measuring precision (mum magnitude).
2) Although the resonance can effectively improve the testing precision, the measured distance and the instrument form a resonant cavity together, and when the measured distance and the instrument drift, the resonant frequency is changed. Therefore, the drift of the instrument and the change of the measured distance cannot be distinguished by a single resonant cavity, and the influence of the drift of the measuring instrument on the measuring precision is further aggravated by considering the long energy storage optical fiber structure of the OEO; the invention adopts a structure of switching the OEO at an ultra-high speed, the time delay inside the range finder forms an OEO as a test OEO, the time delay inside the range finder and different distances to be tested form other measurement OEOs, the test OEO and the measurement OEO are switched and started to vibrate, when the switching frequency reaches the kHz magnitude, the time delay inside the range finder can be regarded as unchanged within ms, the influence of environmental change on the stability of the time delay inside the range finder is eliminated, and the measurement precision is ensured;
3) the measuring instrument is simple and easy to operate, based on the advantages, the measuring instrument can be widely applied to the fields of industrial measurement and control, precision instrument manufacturing and the like, and the distance measuring system is strong in anti-interference capability and good in concealment, and has a good application prospect in the military field.
Drawings
FIG. 1 is a schematic diagram of a large-range, high-precision absolute distance measuring instrument based on OEO fast switching according to the present invention;
in the figure:
1-an internal delay module of the instrument;
2-a loop switching module;
31-a first laser, 32-a second laser, 3 n-an nth laser;
4-a first wavelength division multiplexer, 4a 1-a first input port of the first wavelength division multiplexer, 4 an-an nth input port of the first wavelength division multiplexer, 4 b-an output port of the first wavelength division multiplexer;
5-a polarization controller;
6-an electro-optic modulator;
7-optical circulator, 7 a-first port of optical circulator, 7 b-second port of optical circulator, 7 c-third port of optical circulator;
8-an optical amplifier;
9-a photodetector;
10-band pass filter;
11-a microwave amplifier;
12-electrical coupler, 12 a-first output port of the electrical coupler, 12 b-second output port of the electrical coupler;
131-test collimator, 132-second measurement collimator, 13 n-nth measurement collimator;
141-a first test mirror, 142-a second measuring mirror, 14 n-an nth measuring mirror;
15-a second wavelength division multiplexer, 15 a-an input port of the second wavelength division multiplexer, 15b 1-a first output port of the second wavelength division multiplexer, 15 bn-an nth output port of the second wavelength division multiplexer;
16-frequency measurement and distance calculation module.
Detailed Description
The invention will be further described with reference to the following figures and specific examples, which are not intended to limit the invention in any way.
As shown in fig. 1, the large-range and high-precision absolute distance measuring instrument based on OEO fast switching according to the present invention includes an instrument internal delay module 1, a loop switching module 2, and a frequency measurement and distance calculation module 16, wherein the instrument internal delay module 1 and the loop switching module 2 are connected by an optical fiber and a cable to form a multi-cavity switching optoelectronic oscillator structure; the instrument internal delay module 1 is connected with the frequency measurement and distance calculation module 16.
The internal delay module 1 of the instrument comprises n lasers, a first wavelength division multiplexer 4, a polarization controller 5, an electro-optical modulator 6, an optical circulator 7, an optical amplifier 8, a photoelectric detector 9, a band-pass filter 10, a microwave amplifier 11 and an electric coupler 12; the first wavelength division multiplexer 4 has n input ports and 1 output port; the n lasers are connected with n input ports of a first wavelength division multiplexer 4, an output port of the first wavelength division multiplexer 4 is connected with a polarization controller 5, and the polarization controller 5 is connected with an electro-optical modulator 6; the electro-optical modulator 6 is one of a lithium niobate intensity modulator, a lithium niobate phase modulator, and an electro-absorption modulator of a semiconductor structure.
The loop switching module 2 comprises n reflectors, n collimators and a second wavelength division multiplexer 15; the n mirrors include 1 test mirror 141 and n-1 measurement mirrors, the n collimators include 1 test collimator 131 and n-1 measurement collimators, and the second wavelength division multiplexer 15 has one input port and n output ports; the n collimators are connected with the n output ports of the second wavelength division multiplexer 15, the centers of the mirror surfaces of the 1 test reflectors correspond to the lens focuses of the 1 test collimators, and the centers of the mirror surfaces of the n-1 test reflectors correspond to the lens focuses of the n-1 measurement collimators one by one respectively.
In the present invention, the n lasers are respectively referred to as a first laser 31, a second laser 32, … …, and an nth laser 3 n. The type of the laser is a semiconductor laser or a fiber laser, and the n lasers are the same type of laser. The n-1 measuring reflectors are respectively marked as a second measuring reflector 142, a second measuring reflector … … and an nth measuring reflector 14n, the testing reflector 141 and the n-1 measuring reflectors (142-14 n) are devices or structures with optical field reflection and certain transmission characteristics, can be reflectors formed by an optical circulator and a coupler together, can be reflectors of a sagnac ring structure formed by a non-3 dB optical fiber coupler, can also be optical fiber reflectors with certain transmission function and coated optical fiber end faces, and can also be Faraday optical rotation mirrors. The n-1 measurement collimators are respectively denoted as a second measurement collimator 132, … …, an nth measurement collimator 13 n.
The electro-optical modulator 6 is connected with the input port of the second wavelength division multiplexer 15 and the optical amplifier 8 through the optical circulator 7. The optical circulator 7 has three ports, which are respectively marked as a first port 7a, a second port 7b and a third port 7c, wherein the first port 7a is connected with the electro-optical modulator 6, the second port 7b is connected with an input port 15a of a second wavelength division multiplexer, and the third port 7c is connected with the optical amplifier 8, so that the connected internal delay module 1 and the loop switching module 2 of the instrument jointly form an optical-electrical oscillator (OEO) structure with multi-cavity switching. As the first laser 31 and the second laser 32, the first laser 31 and the third laser 33, the first lasers 31 and … …, the first laser 31 and the n-th laser 3n are driven to switch, the length of the resonant cavity is rapidly switched between the sum of the intrinsic length inside the instrument and the reference distance and the sum of the intrinsic length inside the instrument and the respective distances to be measured.
The optical amplifier 8 is a device having an amplification effect on an optical signal, and may be an erbium-doped optical fiber amplifier, an ytterbium-doped optical fiber amplifier, a thulium-doped optical fiber amplifier, or a semiconductor optical amplifier. The optical amplifier 8 is connected with a band-pass filter 10 through the photodetector 9, the band-pass filter 10 is connected with an input port of an electric coupler 12 through a microwave amplifier 11, a first output port 12a of the electric coupler 12 is connected with a radio frequency input port of the electro-optical modulator 6, and a second output port 12b of the electric coupler 12 is connected with a frequency metering and distance calculating module 16.
The resonant frequency of an OEO is determined by two factors: 1) an oscillation mode determined by loop delay; 2) selecting a mode device; the distance to be measured is used as a part of an OEO oscillation loop, and the distance to be measured can be deduced by measuring the resonant frequency.
The interval of the oscillation starting mode of the OEO oscillation loop, i.e. the fundamental frequency fbThe delay of the optical signal is determined by the loop, namely:
fb＝1/τ (1)
in the formula (1), τ is a delay amount.
The delay can be divided into two parts, the fixed delay tau formed by the circuit and the fixed optical fiber0And a delay τ determined by the distance L to be measuredLWhere n is the refractive index and c is the speed of light in vacuum. Thus, it is possible to obtain:
due to f in the oscillatorbThe integral multiple frequency can satisfy the oscillation condition of OEO, the actual resonant frequency f of OEONThe mode selection is carried out through a microwave filter, and the following requirements are met:
fN＝Nfb(3)
in the formula (3), N is a natural number, and it can be seen that the actual resonance frequency fNAt a fundamental frequency fbN times, for example: an accuracy of 1 μm is to be achieved over a length of 500m (fundamental frequency 300kHz), for the fundamental frequency fbThe frequency detection precision of the frequency detection circuit is 0.0006 Hz; under the condition of 30GHz, the N value is 105By order of magnitude, the variation in fundamental frequency due to this relationship is amplified by a factor of N (a 1 μm variation results in a 60Hz resonance frequency), and it can be seen that: in the same viewUnder the premise of measuring conditions and measuring precision, directly measuring fbIs far less than the value of measurement fNAnd N and fbThe obtained precision is high, and the measurement error is greatly reduced, so that the distance L to be measured can be obtained by the following formula:
thus, the accuracy of the measurement of the distance L to be measured in fact depends on two factors: f. ofNAnd the correctness of the value of N, wherein fNThe theoretical accuracy of (assuming sufficiently high test accuracy) depends on the spectral purity of the oscillator output frequency, and corresponding research work has shown that high quality microwave source output with spectral purity of mHz can be obtained with OEO structures. From the equation (4), the sum of the distances to be measured fNThe correlation of (c). Theoretically, an accurate measurement of L can be obtained as long as the correctness of N is guaranteed.
The value of N can be measured by rough measurement fbThe method of (1) yields:
in the formula (5), the reaction mixture is,
the symbol represents a rounding operation, fb *Representing the fundamental frequency, fbA coarse measurement of.
By measuring fNAnd fb *The value of (c) can be obtained by obtaining the corresponding value of N and then fbThe accurate value obtains the ring length information, and high-precision measurement of the distance is realized.
Examples
As shown in fig. 1, the large-scale, high-precision absolute distance measuring instrument based on OEO fast switching includes an instrument internal delay module 1 and a loop switching module 2, wherein the instrument internal delay module 1 includes: a first laser 31, … …, an nth laser 3n, a first wavelength division multiplexer 4, a polarization controller 5, an electro-optical modulator 6, an optical circulator 7, an optical amplifier 8, a photodetector 9, a band-pass filter 10, a microwave amplifier 11, an electric coupler 12, the first laser 31, … … and the nth laser 3n are connected with the polarization controller 5, the polarization controller 5 is connected with the electro-optical modulator 6, the electro-optical modulator 6 is connected with the first port 7a of the optical circulator, the third port 7c of the optical circulator is connected with the optical amplifier 8, the optical amplifier 8 is connected with the photodetector 9, the photodetector 9 is connected with the band-pass filter 10, the band-pass filter 10 is connected with the microwave amplifier 11, the microwave amplifier 11 is connected with the electric coupler 12, the first output port 12a of the electric coupler is connected with the radio frequency input port of the electro-optical modulator, and the second output port 12b of the electric coupler is connected with the frequency metering and distance calculating module 16.
The loop switching module 2 comprises a test collimator 131, second measurement collimators 132 and … …, an nth measurement collimator 13n, a test reflector 141, second measurement reflectors 142 and … …, and an nth measurement reflector 14n, wherein the third ports 6c of the second wavelength division multiplexer 15 and the optical circulator are connected with a second wavelength division multiplexer input port 15a, a second wavelength division multiplexer output port 15b1 is connected with the test collimator 131, a second wavelength division multiplexer output port 15b2 is connected with the second measurement collimator 132, by analogy, the second wavelength division multiplexer output port 15b n is connected to the nth measuring collimator 13n, the measuring collimator 131 is aligned with the measuring reflector 141 through the reference distance a1, the second measuring collimator 132 is aligned with the second measuring reflector 142 through the second to-be-measured distance a2, and the nth measuring collimator 13n is aligned with the nth measuring reflector 14n through the nth to-be-measured distance An; the first laser 31, … … and the nth laser 3n are all bragg feedback semiconductor lasers; the electro-optical modulator 6 is a lithium niobate intensity modulator; the optical amplifier 8 is an erbium-doped fiber amplifier; the test mirror 141, the second measurement mirrors 142, … …, and the nth measurement mirror 14n are all faraday rotation mirrors.
When the optical modulator is used specifically, an optical signal emitted by the first laser 31 enters through the first input port 4a1 of the first wavelength division multiplexer 4, then enters the electro-optical modulator 6 through the polarization controller 5, and the modulated optical signal enters light through the first port 7a of the optical circulatorThe circulator 7 is output from the second port 7b of the optical circulator and enters the second wavelength division multiplexer 15, is injected onto the test light reflector 141 through the first output port 12b1 of the second wavelength division multiplexer by a reference distance A1, is reflected back to the first output port 15b1 of the second wavelength division multiplexer, enters the optical circulator 7 from the second port 7b of the optical circulator after passing through the second wavelength division multiplexer 15, is output from the third port 7c of the optical circulator and enters the optical amplifier 8; when the second laser 32 is connected, an optical signal emitted by the second laser 32 enters through the second input port 4a2 of the first wavelength division multiplexer 4, and then enters the electro-optical modulator 6 through the polarization controller 5, the modulated optical signal enters the optical circulator 7 through the first port 7a of the optical circulator, is output from the second port 7b of the optical circulator and enters the second wavelength division multiplexer 15, is injected onto the second measurement optical reflector 142 through the second output port 15b2 of the second wavelength division multiplexer 15 and a section of distance a2 to be measured, is reflected back to the second output port 12b2 of the second wavelength division multiplexer, enters the optical circulator 7 through the second port 7b of the optical circulator after passing through the second wavelength division multiplexer 15, is output from the third port 7c of the optical circulator, and then enters the amplifier 8; when the nth laser 3n is switched on, an optical signal emitted by the nth laser 3n enters through an nth input port 4an of the first wavelength division multiplexer 4 and then enters the electro-optical modulator 6 through the polarization controller 5, the modulated optical signal enters the optical circulator 7 through a first port 7a of the optical circulator and then is output through a second port 7b of the optical circulator to enter the second wavelength division multiplexer 15, is injected to the nth measuring light reflector 14n through the nth output port 15bn of the second wavelength division multiplexer by a distance An to be measured, then the optical signal is reflected back to the nth output port 15bn of the second wavelength division multiplexer, enters the optical circulator 7 through the second port 7b of the optical circulator after passing through the second wavelength division multiplexer 15, is output through the third port 7c of the optical circulator and then enters the optical amplifier 8, and the optical signal amplified by the optical amplifier 8 is injected into the photoelectric detector 9; the optical signal is converted into a microwave signal by the photodetector 9, and then is divided into two parts by the electric coupler 12 after passing through the band-pass filter 10 and the microwave amplifier 11, namely, a first output port 12a of the electric coupler, a second output port 12b of the electric coupler, and the electric couplerThe first output port 12a is used as a modulation signal of the modulator to drive the electro-optical modulator 6 to form a closed feedback loop, and the second output port 12b of the electric coupler is used as an output signal to be connected with the frequency metering and distance conversion module 16; when the first laser 31 is switched on, the feedback loop forms an OEO, defined as a test OEO, and the output signal is fN1For calculating the cavity length L of the test OEO1(ii) a When the second laser 32 is switched on, the feedback loop forms an OEO, defined as the second measured OEO, with the output signal fN2For calculating the cavity length L of the second measurement OEO2Wherein the length of the distance to be measured in the first space is A1+ L2-L1(ii) a When the nth laser 3n is turned on, the feedback loop forms an OEO, defined as the nth measured OEO, and the output signal is fNnFor calculating the cavity length L of the n-th measured OEOnWherein the length of the distance to be measured in the nth section of space is A1+ Ln-L1。
In summary, the absolute distance measuring instrument of the present invention utilizes the characteristics of long OEO resonant cavity, high spectral purity and high resonant frequency to amplify the measured change by 105～106The absolute distance measurement (km magnitude) in a large range can be carried out by using a common measuring instrument, and the high measurement precision (mum level) can be achieved; the structure of switching the OEO at the ultrahigh speed is adopted, one OEO is formed by the time delay inside the distance measuring instrument and a fixed reference distance and serves as a test OEO, the time delay inside the distance measuring instrument and different distances to be measured form other measurement OEOs, the test OEO and the measurement OEO are switched and started to vibrate, when the switching frequency reaches the kHz magnitude, the time delay inside the distance measuring instrument can be regarded as unchanged within ms, therefore, the influence of environmental change on the stability of the time delay inside the distance measuring instrument is eliminated, and the measuring accuracy is guaranteed.
While the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are illustrative only and not restrictive, and various modifications which do not depart from the spirit of the present invention and which are intended to be covered by the claims of the present invention may be made by those skilled in the art.
Claims (7)
1. A large-range and high-precision absolute distance measuring instrument based on OEO fast switching is characterized by comprising an instrument internal delay module (1), a loop switching module (2) and a frequency metering and distance calculating module (16), wherein the instrument internal delay module (1) and the loop switching module (2) are connected through an optical fiber and a cable to form a multi-cavity switching photoelectric oscillator structure; and the instrument internal delay module (1) is connected with the frequency measurement and distance calculation module (16).
2. The OEO fast switching based large scale, high precision absolute distance measuring instrument according to claim 1, characterized in that the instrument internal delay module (1) comprises n lasers, a first wavelength division multiplexer (4), a polarization controller (5), an electro-optical modulator (6), an optical circulator (7), an optical amplifier (8), a photo detector (9), a band pass filter (10), a microwave amplifier (11) and an electrical coupler (12); the first wavelength division multiplexer (4) has n input ports and 1 output port; the n lasers are connected with n input ports of a first wavelength division multiplexer (4), an output port of the first wavelength division multiplexer (4) is connected with a polarization controller (5), and the polarization controller (5) is connected with an electro-optical modulator (6);
the loop switching module (2) comprises n reflectors, n collimators and a second wavelength division multiplexer (15); said n mirrors including 1 test mirror and n-1 measurement mirrors, said n collimators including 1 test collimator and n-1 measurement collimators, said second wavelength division multiplexer (15) having one input port and n output ports; the n collimators are connected with n output ports of the second wavelength division multiplexer (15), the centers of the mirror surfaces of 1 test reflector of 1 test collimator correspond to the lens focuses of 1 test collimator, and the centers of the mirror surfaces of n-1 reflectors respectively correspond to the lens focuses of n-1 measurement collimators one by one;
the electro-optical modulator (6) is respectively connected with the input port of the second wavelength division multiplexer (15) and the optical amplifier (8) through the optical circulator (7);
the optical amplifier (8) is connected with the band-pass filter (10) through the photoelectric detector (9), the band-pass filter (10) is connected with an input port of the electric coupler (12) through the microwave amplifier (11), a first output port (12a) of the electric coupler (12) is connected with a radio frequency input port of the electro-optical modulator (6), and a second output port (12b) of the electric coupler (12) is connected with the frequency metering and distance calculating module (16).
3. The OEO fast switching based wide range, high accuracy absolute distance measuring instrument according to claim 2, characterized in that the optical circulator has three ports, denoted first port (7a), second port (7b) and third port (7c), respectively, wherein the first port (7a) is connected to the electro-optical modulator (6), the second port (7b) is connected to the input port (15a) of the second wavelength division multiplexer, and the third port (7c) is connected to the optical amplifier (8).
4. The OEO fast switching based large scale, high accuracy absolute distance measuring instrument according to claim 3, characterized in that the connection of said second port (7b) with the input port (15a) of the second wavelength division multiplexer constitutes a multi-cavity switched opto-electronic oscillator configuration.
5. The OEO fast switching based wide range, high accuracy absolute distance measuring instrument according to claim 1, wherein the type of laser is a semiconductor laser or a fiber laser and the n lasers are the same type of laser.
6. The OEO fast switching based large scale, high precision absolute distance measuring instrument according to claim 1, characterized in that the electro-optical modulator (6) is one of a lithium niobate intensity modulator, a lithium niobate phase modulator and an electro-absorption modulator of semiconductor structure.
7. The OEO fast switching based wide range, high accuracy absolute distance measuring instrument according to any one of claims 1-6, wherein said optical amplifier (8) is one of an erbium doped fiber amplifier, an ytterbium doped fiber amplifier, a thulium doped fiber amplifier and a semiconductor optical amplifier.
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| CN201911245313.2A CN111060896A (en) | 2019-12-06 | 2019-12-06 | Large-range and high-precision absolute distance measuring instrument based on OEO (optical output interface) quick switching |
| PCT/CN2019/127671 WO2021109284A1 (en) | 2019-12-06 | 2019-12-23 | Oeo quick switching-based wide-range and high-precision absolute distance measurement instrument |
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| CN112731353A (en) * | 2020-12-22 | 2021-04-30 | 天津大学 | High-precision optical calibration device and method for large-range distance measurement |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102353963A (en) * | 2011-07-15 | 2012-02-15 | 于晋龙 | Distance measuring system for optical domain based dual-loop optoelectronic oscillators |
| CN104950311A (en) * | 2015-07-03 | 2015-09-30 | 天津大学 | OEO (optoelectronic oscillator) based wide-range and high-precision absolute distance measurement system with self-calibration function |
| WO2017031575A1 (en) * | 2015-08-21 | 2017-03-02 | Nanowave Technologies Inc. | Optoelectronic oscillator with tunable filter |
| CN109669189A (en) * | 2019-01-19 | 2019-04-23 | 南京合太光电科技有限公司 | Wide range, the high-precision absolute distance meter device being switched fast based on OEO |
| CN209979850U (en) * | 2019-01-19 | 2020-01-21 | 南京合太光电科技有限公司 | Large-range and high-precision absolute distance measuring instrument based on OEO (optical output interface) quick switching |
| CN110940991A (en) * | 2019-11-08 | 2020-03-31 | 南京合太光电科技有限公司 | Large-distance and micro-relative-distance measuring instrument based on OEO (optical emission output) rapid switching |
-
2019
- 2019-12-06 CN CN201911245313.2A patent/CN111060896A/en active Pending
- 2019-12-23 WO PCT/CN2019/127671 patent/WO2021109284A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102353963A (en) * | 2011-07-15 | 2012-02-15 | 于晋龙 | Distance measuring system for optical domain based dual-loop optoelectronic oscillators |
| CN104950311A (en) * | 2015-07-03 | 2015-09-30 | 天津大学 | OEO (optoelectronic oscillator) based wide-range and high-precision absolute distance measurement system with self-calibration function |
| WO2017031575A1 (en) * | 2015-08-21 | 2017-03-02 | Nanowave Technologies Inc. | Optoelectronic oscillator with tunable filter |
| CN109669189A (en) * | 2019-01-19 | 2019-04-23 | 南京合太光电科技有限公司 | Wide range, the high-precision absolute distance meter device being switched fast based on OEO |
| CN209979850U (en) * | 2019-01-19 | 2020-01-21 | 南京合太光电科技有限公司 | Large-range and high-precision absolute distance measuring instrument based on OEO (optical output interface) quick switching |
| CN110940991A (en) * | 2019-11-08 | 2020-03-31 | 南京合太光电科技有限公司 | Large-distance and micro-relative-distance measuring instrument based on OEO (optical emission output) rapid switching |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112731353A (en) * | 2020-12-22 | 2021-04-30 | 天津大学 | High-precision optical calibration device and method for large-range distance measurement |
| CN112731353B (en) * | 2020-12-22 | 2022-05-06 | 天津大学 | High-precision optical calibration device and method for large-range distance measurement |
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