阅读说明：本技术 测距装置及方法 (Distance measuring device and method ) 是由 高超 纪荣祎 董登峰 周维虎 石俊凯 潘映伶 于 2021-08-09 设计创作，主要内容包括：本公开提供一种测距装置和方法,装置包括：偏振光产生模块,用于产生线偏振光；相位调制模块,用于调制线偏振光的相位,输出调制得到的偏振光到被测物产生反射光,以及调制反射光的相位,反射光用于测距；分束装置,用于对经相位调制模块调制后的反射光进行检偏；其中,相位调制模块包括相位调制器和波片,偏振光产生模块与分束装置之间通过第一保偏光纤传输,分束装置与相位调制器之间通过第二保偏光纤传输,第二保偏光纤用于控制线偏振光和相位调制器中电场间的夹角为第一角度,以及相位调制器与波片之间通过第三保偏光纤传输,第三保偏光纤的快轴与波片的快轴夹角为第二角度,第一角度和第二角度相等或互补。(The present disclosure provides a ranging apparatus and method, the apparatus comprising: the polarized light generating module is used for generating linearly polarized light; the phase modulation module is used for modulating the phase of linearly polarized light, outputting the polarized light obtained by modulation to a measured object to generate reflected light and modulating the phase of the reflected light, and the reflected light is used for ranging; the beam splitting device is used for analyzing the reflected light modulated by the phase modulation module; wherein, the phase modulation module includes phase modulator and wave plate, the polarized light produces and transmits through first polarization maintaining fiber between module and the beam splitting device, transmit through second polarization maintaining fiber between beam splitting device and the phase modulator, second polarization maintaining fiber is arranged in the contained angle between control line polarized light and electric field in the phase modulator to be first angle to and transmit through third polarization maintaining fiber between phase modulator and the wave plate, the fast axis of third polarization maintaining fiber is the second angle with the fast axis contained angle of wave plate, first angle and second angle are equal or complementary.)

1. A ranging apparatus, comprising:

the polarized light generating module (A) is used for generating linearly polarized light;

the phase modulation module (B) is used for modulating the phase of the linearly polarized light, outputting the polarized light obtained by modulation to a measured object to generate reflected light and modulating the phase of the reflected light, wherein the reflected light is used for ranging;

the beam splitting device (4) is used for analyzing the reflected light modulated by the phase modulation module (B);

wherein, phase modulation module (B) includes phase modulator (5) and wave plate (6), polarized light produce module (A) with transmit through first polarization maintaining fiber (31) between beam splitting device (4), beam splitting device (4) with transmit through second polarization maintaining fiber (32) between phase modulator (5), second polarization maintaining fiber (32) are used for controlling linearly polarized light with contained angle between the electric field is first angle in phase modulator (5), and phase modulator (5) with transmit through third polarization maintaining fiber (33) between wave plate (6), the fast axis of third polarization maintaining fiber (33) with the fast axis contained angle of wave plate (6) is the second angle, first angle with the second angle equals or is complementary.

2. The ranging apparatus as claimed in claim 1, further comprising:

the spatial reflection optical module (C) is used for transmitting the polarized light after the phase modulation in a distance measuring space and generating reflection light;

a control module (D) for sending a modulation signal to the phase modulation module (B) and calculating a distance from the intensity of the reflected light.

3. A ranging device according to claim 2, characterized in that said control module (D) comprises:

a photodetector (9), a control circuitry (10) and a modulation signal generating unit (11);

the photoelectric detector (9) is used for converting the reflected light into an electric signal, and the control circuit system (10) is used for calculating a distance according to the electric signal and controlling the modulation signal generating unit (11) to send a modulation signal to the phase modulation module (B), wherein the modulation signal is a trigonometric function signal.

4. The ranging device according to claim 2, characterized in that said reflected light generating module (C) comprises:

a beam expander (7) and a mirror (8);

wherein, beam expander (7) are used for behind the modulation phase polarized light expand the beam, speculum (8) set up on the testee for after the reflection expands polarized light, beam expander (7) with distance between speculum (8) is surveyed spatial distance.

5. A ranging device as claimed in claim 2, characterized in that said beam splitting means (4) comprise:

polarization maintaining fiber coupler or beam splitter or circulator.

6. A ranging device as claimed in claim 1, characterized in that said polarized light generating module (a) comprises:

a linearly polarized light source (1'); alternatively, the first and second electrodes may be,

a broadband light source (1) and an isolator (2);

the linearly polarized light source (1') is used for generating the linearly polarized light, the broadband light source (1) is used for generating wide-spectrum low-coherence light, and the isolator (2) is used for generating the linearly polarized light by utilizing the wide-spectrum low-coherence light.

7. A ranging device as claimed in claim 1, characterized in that said first angle and said second angle are 45 ° or 135 °.

8. A ranging device according to claim 1, characterized in that the phase modulator (5) is a straight waveguide electro-optical phase modulator.

9. A ranging device as claimed in claim 1, characterized in that said wave plate (6) is an 1/4 wave plate.

10. A method of ranging, comprising:

linearly polarized light is generated through a polarized light generating module (A);

transmitting the linearly polarized light to a phase modulation module (B) by adopting a polarization maintaining optical fiber (3);

modulating the linearly polarized light by utilizing a trigonometric function signal to obtain polarized light, and reflecting the polarized light by a reflector (8) on a measured object to obtain reflected light;

moving the mirror (8), modulating the reflected light with the trigonometric function signal, and measuring the intensity of the modulated reflected light;

and calculating to obtain the measured distance according to the frequency value of the trigonometric function signal corresponding to the maximum value or the minimum value of the intensity of the reflected light.

Technical Field

The disclosure relates to the technical field of industrial measurement, in particular to a distance measuring device and method.

Background

The large-size industrial measurement range is between several meters and dozens of meters, and the high-precision absolute distance measurement is the technical basis of various measurement equipment adopted in the large-size industrial measurement.

In the existing device and method based on laser polarization modulation distance measurement, a spatial volume phase modulator and a waveguide phase modulator are mostly adopted, and are systems based on a spatial light path. The space body phase modulator needs higher driving voltage, high-frequency and high-voltage electric signals are heated to easily cause temperature drift, a complex temperature control system is needed, and the space collimating optical path puts high requirements on instrument processing and assembly. In order to meet the control requirement on the polarization state of a transmission optical signal, the polarization ranging system adopting the waveguide phase modulator has the problems that optical fiber devices are not completely adopted, an optical path system is complex and the like, and the advantages of the laser polarization ranging system cannot be fully exerted.

Disclosure of Invention

Technical problem to be solved

In view of the above technical problems, the present disclosure provides a distance measuring device and method for at least partially solving the above technical problems.

(II) technical scheme

The present disclosure provides a ranging apparatus, including: the polarized light generating module A is used for generating linearly polarized light; the phase modulation module B is used for modulating the phase of linearly polarized light, outputting the polarized light obtained by modulation to a measured object to generate reflected light and modulating the phase of the reflected light, and the reflected light is used for ranging; the beam splitting device 4 is used for analyzing the reflected light modulated by the phase modulation module B; wherein, phase modulation module B includes phase modulator 5 and wave plate 6, the polarized light produces and transmits through first polarization maintaining fiber 31 between module A and the beam splitting device 4, transmit through second polarization maintaining fiber 32 between beam splitting device 4 and the phase modulator 5, second polarization maintaining fiber 32 is used for controlling the contained angle between electric field in line polarized light and the phase modulator 5 and is first angle to and transmit through third polarization maintaining fiber 33 between phase modulator 5 and the wave plate 6, the fast axis of third polarization maintaining fiber 33 and the fast axis contained angle of wave plate 6 are the second angle, first angle and second angle are equal or complementary.

Optionally, the distance measuring device further comprises: the spatial reflection optical module C is used for transmitting the polarized light after the phase modulation in the distance measuring space and generating reflected light; and the control module D is used for sending the modulation signal to the phase modulation module B and calculating the distance according to the intensity of the reflected light.

Optionally, the control module D comprises: a photodetector 9, a control circuit system 10 and a modulation signal generating unit 11; the photodetector 9 is configured to convert the reflected light into an electrical signal, and the control circuit system 10 is configured to calculate a distance according to the electrical signal and control the modulation signal generating unit 11 to send a modulation signal to the phase modulation module B, where the modulation signal is a trigonometric function signal.

Optionally, the reflected light generating module C includes: a beam expander 7 and a mirror 8; wherein, beam expander 7 is used for expanding the polarized light behind the modulation phase place, and speculum 8 sets up on the measured object for the polarized light after the reflection expands, and the distance between beam expander 7 and the speculum 8 is surveyed spatial distance.

Optionally, the beam splitting means 4 comprises: polarization maintaining fiber coupler or beam splitter or circulator.

Optionally, the polarized light generating module a comprises: a linearly polarized light source 1'; alternatively, the broadband light source 1 and the isolator 2; the linear polarized light source 1' is used for generating linear polarized light, the broadband light source 1 is used for generating wide-spectrum low-coherence light, and the isolator 2 is used for generating linear polarized light by utilizing the wide-spectrum low-coherence light.

Optionally, the first angle and the second angle are 45 ° or 135 °.

Optionally, the phase modulator 5 is a straight waveguide electro-optic phase modulator.

Optionally, wave plate 6 is an 1/4 wave plate.

Another aspect of the present disclosure provides a ranging method, including: linearly polarized light is generated through the polarized light generating module A; transmitting linearly polarized light to a phase modulation module B by adopting a polarization maintaining optical fiber; modulating the linearly polarized light by utilizing a trigonometric function signal to obtain polarized light, and reflecting the polarized light by a reflector 8 on a measured object to obtain reflected light; moving the reflecting mirror 8, modulating the reflected light by utilizing a trigonometric function signal, and measuring the intensity of the modulated reflected light; and calculating the measured distance according to the frequency value of the trigonometric function signal corresponding to the maximum value or the minimum value of the intensity of the reflected light.

(III) advantageous effects

The utility model provides a range unit adopts polarization maintaining fiber transmission line polarization light, through the alignment angle of rational design polarization maintaining fiber, can guarantee the polarization state of light signal, has simplified the light path structure of system greatly.

According to the distance measuring device provided by the disclosure, the linear-wave conductive optical phase modulator is driven by the trigonometric function signal to modulate linearly polarized light, the voltage amplitude required by the system is about half of half-wave voltage, and the complexity of a circuit system is greatly reduced. Meanwhile, the method is beneficial to obtaining a larger sweep frequency range, and expanding the working frequency bandwidth of the modulator, so that the measurement precision and the measurement distance of the distance measuring device can be improved, and the absolute distance measurement with large-range high precision can be realized.

The distance measuring device provided by the disclosure has the advantages of simple system light path and circuit structure, high reliability, convenience for application in industrial measurement, and wide application prospect in the fields of aerospace, military and the like.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

FIG. 1 schematically illustrates a ranging device structure according to an embodiment of the disclosure;

FIG. 2 schematically illustrates a ranging apparatus structure according to another embodiment of the present disclosure;

FIG. 3 schematically illustrates a ranging apparatus structure according to yet another embodiment of the present disclosure;

fig. 4 schematically illustrates a flow chart of a ranging method according to an embodiment of the present disclosure.

[ description of reference ]

1' -linearly polarized light source

1-broadband light source

2-isolator

31-first polarization maintaining fiber

32-second polarization maintaining fiber

33-third polarization maintaining fiber

4-Beam splitting device

5-phase modulator

6-wave plate

7-Beam expander

8-reflecting mirror

9-photoelectric detector

10-control circuitry

11-modulation signal generating unit

A-polarized light generating module

B-phase modulation module

C-space reflective optical module

D-control module

Detailed Description

For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.

It should be noted that in the drawings or description, the same drawing reference numerals are used for similar or identical parts. Features of the embodiments illustrated in the description may be freely combined to form new embodiments without conflict, and each claim may be individually referred to as an embodiment or features of the claims may be combined to form a new embodiment, and in the drawings, the shape or thickness of the embodiment may be enlarged and simplified or conveniently indicated. Further, elements or implementations not shown or described in the drawings are of a form known to those of ordinary skill in the art. Additionally, while exemplifications of parameters including particular values may be provided herein, it is to be understood that the parameters need not be exactly equal to the respective values, but may be approximated to the respective values within acceptable error margins or design constraints.

Unless a technical obstacle or contradiction exists, the above-described various embodiments of the present disclosure may be freely combined to form further embodiments, which are all within the scope of protection of the present disclosure.

While the present disclosure has been described in connection with the accompanying drawings, the embodiments disclosed in the drawings are intended to be illustrative of the preferred embodiments of the disclosure, and should not be construed as limiting the disclosure. The dimensional proportions in the drawings are merely schematic and are not to be understood as limiting the disclosure.

Although a few embodiments of the present general inventive concept have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.

Fig. 1 schematically shows a structure of a ranging apparatus according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, as shown in fig. 1, a ranging apparatus includes, for example: the polarized light generating module A is used for generating linearly polarized light. And the phase modulation module B is used for modulating the phase of the linearly polarized light to generate polarized light. And the spatial reflection optical module C is used for generating reflection light by utilizing the polarized light after the phase modulation. And the beam splitting device 4 is used for analyzing the reflected light modulated by the phase modulation module B. And a control module D for sending the modulation signal to the phase modulation module B and calculating the distance according to the intensity of the reflected light. The polarized light is transmitted between the polarized light generating module a and the beam splitting device 4 through the first polarization maintaining fiber 31, transmitted between the beam splitting device 4 and the phase modulating module B through the second polarization maintaining fiber 32, and transmitted after the linearly polarized light in the phase modulating module B is modulated into polarized light. Linearly polarized light generated by the polarized light generating module A is transmitted to the phase modulation module B through the polarization maintaining optical fiber, the phase modulation module B modulates the linearly polarized light under the driving of a modulation signal sent by the control module D, the polarized light obtained through modulation measures the size or a certain distance of an object to be measured in the space reflection light module C in a mode of generating reflected light through reflection, and then the reflected light returns along an original light path, is modulated in the phase modulation module B and is detected by the control module D after being split by the beam splitting device 4. The modulation signals with different frequencies can be modulated to obtain modulated reflected light with different intensities, the frequency value of the modulation signal corresponding to the moment of the extreme value (maximum value or minimum value) of the reflected light energy is found, and the measured size or distance can be obtained by solving. The modulation signal may be a trigonometric function signal such as a sine wave signal or a cosine wave signal.

Fig. 2 schematically shows a structure of a ranging apparatus according to another embodiment of the present disclosure.

According to an embodiment of the present disclosure, as shown in fig. 2, the polarized light generating module a includes, for example: a linearly polarized light source 1'. The phase modulation block B includes, for example: a phase modulator 5 and a wave plate 6. The spatial reflection light module C includes, for example: a beam expander 7 and a mirror 8. The control module D includes, for example: a photodetector 9, control circuitry 10 and a modulation signal generating unit 11. The beam splitting device 4 is, for example, a circulator, a polarization maintaining fiber coupler, or a beam splitter, and can realize bidirectional optical signal transmission, the phase modulator 5 is, for example, a straight wave conductive optical phase modulator, the wave plate 6 is, for example, an 1/4 wave plate, the mirror 8 is, for example, a mirror mounted on the object to be measured, the photodetector 9 is, for example, a PIN photodetector or an APD photodetector, and the modulation signal generating unit 11 outputs, for example, a sine wave modulation signal. Linearly polarized light generated by the linearly polarized light source 1' enters a port I of the polarization-maintaining optical fiber circulator along the polarization-maintaining optical fiber and is still linearly polarized light after being output through the port II. The included angle between the fast axis of the polarization maintaining optical fiber of the port II and the fast axis of the polarization maintaining optical fiber of the input port of the straight waveguide electro-optic phase modulator is 45 degrees or 135 degrees, for example, and linearly polarized light enters the straight waveguide electro-optic phase modulator and is output after being modulated by a sine wave modulation signal. The included angle between the fast axis of the polarization maintaining fiber of the output port of the straight waveguide electro-optic phase modulator and the fast axis of the wave plate of the optical fiber 1/4 is 45 degrees or 135 degrees, for example. The two included angles are 45 degrees or 135 degrees, so that the polarization component of the linearly polarized light can be decomposed into x and y axes (namely a fast axis and a slow axis) in an equal component mode, and the consistency of polarization state modulation of the polarized light is guaranteed. The polarized light output by the 1/4 wave plate is expanded by the optical fiber collimation beam expander and then transmitted to the reflector 8 fixedly connected with the measured object along the space. Placing the 1/4 wave plate behind the modulator can adjust the phase of the modulated polarized light, for example, to and fro to generate 1/2 phase change, further ensuring the polarization state of the transmitted light in space. The reflected light returns along the original light path and sequentially passes through the optical fiber collimation beam expander, the optical fiber 1/4 wave plate and the straight wave conductive optical phase modulator, and after polarized light subjected to sine wave secondary modulation enters the port II of the polarization-maintaining optical fiber circulator, the polarized light is output through the port III of the circulator and is detected by the photoelectric detector 9. The modulation signal generation unit 11 outputs a sweep frequency modulation sinusoidal modulation signal to the phase modulator 5 at a fixed frequency interval, for example, polarized light (i.e., reflected light) modulated by sinusoidal signals with different frequencies is collected at the photodetector 9 to obtain different light intensity signals, and the control circuit system 10 performs sampling processing on the current signal of the photodetector 9 to calculate and obtain a spatial transmission distance transmitted by the reflected light.

According to an embodiment of the present disclosure, the spatial travel distance of the reflected light may be calculated, for example, by jones 'travel matrix of the polarized light and malus' law. When a sine wave modulation signal is applied, the light intensity detected by the photodetector is:

wherein I (t) is the light intensity detected by the photodetector 9, E₀The energy of the linearly polarized light is output for the linearly polarized light source 1', c is the speed of light, f is the frequency of the sine wave modulation signal, and L is the spatial transmission distance of the reflected light. In the formula (1), the cosine function value corresponding to the minimum value of the reflected light energy (intensity) is 1, and can be obtained as follows:

wherein N represents an arbitrary natural number. Because the frequency of the modulation signal is higher, the problem of multi-period fuzzy distance exists, so that two continuous light energy minimum value points are selected to be substituted into the formula (2), and the following can be obtained:

N₂＝N₁+1 (5)

wherein N is₁、N₂Representing any two consecutive natural numbers, f₁、f₂Representing the frequency of the sine wave corresponding to the minimum points of two continuous light energies. Simultaneous equations (3), (4), and (5) can be obtained:

wherein, the [ alpha ], [ beta ] -a]Representing a rounding operation, f₁、f₂May be directly derived by the sine wave generation module of the control circuitry 10. Substituting the formula (6) into the formula (3) can obtain the spatial transmission distance of the reflected light.

Fig. 3 schematically shows a structure of a ranging apparatus according to still another embodiment of the present disclosure.

According to an embodiment of the present disclosure, as shown in fig. 3, the polarized light generating module a may also include, for example, a broadband light source 1 and an isolator 2. The broadband light source 1 is used for generating broadband spectrum low-coherence light, and the isolator 2 is used for generating linearly polarized light by utilizing the broadband spectrum low-coherence light. The isolator 2 is a device which allows light to pass through in one direction and prevents the light from passing through in the opposite direction, so that the light can be transmitted only in one direction, the light reflected by the optical fiber echo can be well isolated by the isolator 2, and the transmission efficiency of the light wave is improved.

Fig. 4 schematically illustrates a flow chart of a ranging method according to an embodiment of the present disclosure.

Another aspect of the present disclosure provides a ranging method, as shown in fig. 4, for example, the ranging method includes:

and S410, generating linearly polarized light by the polarized light generating module A.

And S420, transmitting the linearly polarized light to the phase modulation module B by adopting a polarization maintaining optical fiber.

And S430, modulating the linearly polarized light by using the trigonometric function signal to obtain polarized light, and reflecting the polarized light by the reflector 8 on the object to be measured to obtain reflected light. S440, the mirror 8 is moved, the reflected light is modulated by the trigonometric function signal, and the intensity of the modulated reflected light is measured.

According to the embodiment of the disclosure, for example, in the spatial distance measurement range, the size of the measured object is represented by moving the reflector 8, the intensity of the reflected light reflected by the reflector 8 before and after the movement is measured, and the measured distance can be obtained by simultaneous solution by substituting the equations (1) to (6). By reasonably optimizing the parameters of the optical device, such as controlling the consistency of forward modulation and backward modulation to make the error within 5%, for example, and adjusting the sweep bandwidth of the sine wave modulation signal to 800 MHz-1 GHz and the sweep step to 100kHz, for example, the measurement accuracy of the order of μm can be realized within the distance of tens of meters to hundreds of meters.

S450, calculating the measured distance according to the frequency value of the trigonometric function signal corresponding to the maximum value or the minimum value of the intensity of the reflected light.

To sum up, the embodiment of the present disclosure provides a distance measuring device. By using the polarization maintaining optical fiber in the system, the optical fiber waveguide device is adopted in the whole system, the alignment of a space optical path is not needed, the requirement on the processing precision of an instrument is lower, the structure of the system is simple and compact, and the reliability of the distance measuring device is improved.

The method embodiment is similar to the apparatus embodiment in portions where details are not given, and please refer to the apparatus embodiment, which is not described herein again.

It should be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy.

It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", etc., mentioned in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present disclosure. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure. And the shapes, sizes and positional relationships of the components in the drawings do not reflect the actual sizes, proportions and actual positional relationships.

In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, the disclosure may lie in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the disclosure.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present disclosure, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. To the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".

The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.