CN214278411U - Laser ranging system of optic fibre - Google Patents
Laser ranging system of optic fibre Download PDFInfo
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- CN214278411U CN214278411U CN202120037949.4U CN202120037949U CN214278411U CN 214278411 U CN214278411 U CN 214278411U CN 202120037949 U CN202120037949 U CN 202120037949U CN 214278411 U CN214278411 U CN 214278411U
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Abstract
The utility model provides a laser rangefinder system of fibre, including interference range finding module, absolute ranging module, wavelength division multiplexing unit, 1 x 2 photoswitch, measurement light path and compensation light path, wherein, interference range finding module, absolute ranging module's output respectively with wavelength division multiplexing unit connects, by wavelength division multiplexing unit coupling and access 1 x 2 photoswitch, an output port of 1 x 2 photoswitch connects measurement light path, another output port connects the compensation light path. The utility model has the advantages that: two beams of light are combined on the same optical fiber through a wavelength division multiplexing device and then output by a collimator, so that the condition of angle mismatch of the two beams of light is avoided.
Description
Technical Field
The utility model relates to a laser survey especially relates to a laser rangefinder system of fibre-optical.
Background
The laser tracker is a high-precision large-size measuring instrument in an industrial measuring system, and can track a space moving target and measure a space three-dimensional coordinate of the target in real time. The host mainly comprises a distance measuring module, an angle measuring module, a tracking control module, a reflector, a foot rest, a data processing terminal and the like. Compared with the traditional laser interferometer, the core distance measurement module has the function of breaking optical continuity and consists of an interference distance measurement module (IFM) and an absolute distance measurement module (ADM), wherein the IFM can only measure the moving distance of a target like the laser interferometer, and the ADM can measure the absolute distance to prevent a reflector from returning to a bird nest to obtain the reference distance again, but the ADM is limited by a distance measurement principle, has low measurement speed and cannot realize dynamic tracking measurement. In the actual distance measurement work of the laser tracker, two sub-modules of the IFM and the ADM are required to be matched with each other to supplement each other.
The respective principle and implementation scheme of the IFM and ADM ranging modules are researched and discussed in various papers and patents, and the key point is the coupling of the two modules in the ranging application of the laser tracker.
Lai is in the coordinate measuring device (patent No. CN 200780009186) and discloses an optical system of a laser tracker, which introduces the implementation scheme and mutual coupling of the IFM and ADM modules in more detail.
The prior art has the following defects:
1. IFM and ADM are difficult to couple and install, and the angular mismatch of two modules in the angular-second order can cause the complete separation of light spots when the measurement target is more than 80 m;
2. the requirement on the structural stability is high, and the coupling effect of the two sub-modules is possibly deteriorated due to transportation, ambient temperature and accidental collision, so that the system fails; stability must be ensured with a costly mechanical structure;
3. the optical fiber is easily interfered by the change of environmental factors such as temperature and the like, and a simple and effective compensation scheme is lacked.
Disclosure of Invention
In order to solve the problems in the prior art, the utility model provides a laser ranging system of fibre-optical.
The utility model provides a laser rangefinder system of fibre, including interference range finding module, absolute ranging module, wavelength division multiplexing unit, 1 x 2 photoswitch, measurement light path and compensation light path, wherein, interference range finding module, absolute ranging module's output respectively with wavelength division multiplexing unit connects, by wavelength division multiplexing unit coupling and access 1 x 2 photoswitch, an output port of 1 x 2 photoswitch connects measurement light path, another output port connects the compensation light path.
As a further improvement of the utility model, the interference distance measuring module comprises a first light source, a first collimator, a first circulator, a 1 x 2 beam splitter, an interference module and a reference module, wherein the first light source is connected with the input end of the first circulator through the first collimator, the forward output end of the first circulator is connected to the 1 × 2 splitter, the backward output end of the first circulator is connected to the interference module, one output port of the 1 × 2 splitter outputs the reference light to the reference module, the other output port outputs measuring light to the wavelength division multiplexing unit, the measuring light and the absolute ranging module are combined into a beam, a returned light signal enters the interference module through the first circulator, the measurement of the relative movement distance of the target is accomplished by detecting the intensity of the interference signal between the measurement light and the reference light.
As a further improvement of the present invention, the first light source, the first collimator, the first circulator, the 1 × 2 beam splitter, the interference module, and the reference module are respectively connected by polarization maintaining optical fibers, and the fast axis or the slow axis of the polarization maintaining optical fibers is aligned with the polarization direction of the light.
As a further improvement of the present invention, the first collimator and the first circulator are integrally processed, and the collimator lens is installed at the input end of the first circulator.
As a further improvement of the utility model, the absolute distance measuring module includes second light source, second collimator, second circulator, modulator and measuring module, wherein, the second light source warp the second collimator with the input of second circulator is connected, the forward output of second circulator with the modulator is connected, the reverse output of second circulator with measuring module connects.
As a further improvement of the present invention, the absolute distance measuring module further includes a third collimator and a fourth collimator, the forward output end of the second circulator is connected to the third collimator to output parallel light and pass through the modulator, and then the modulator is coupled to the fourth collimator, and the tail fiber of the fourth collimator is connected to the wavelength division multiplexing unit, and the interference distance measuring module completes the beam combination.
As a further improvement of the present invention, the modulator is an electro-optic modulator or a fiber waveguide modulator.
As a further improvement of the utility model, the second collimator, the second circulator are as an organic whole processing, collimator lens is installed to the input of second circulator.
As a further improvement of the present invention, the measurement optical path includes a fifth collimator, 1/4 wave plates and a reflector, the input end of the fifth collimator is connected to the 1 × 2 optical switch, and the optical signal output by the fifth collimator is transmitted to the reflector through the 1/4 wave plates.
As a further improvement, the fifth collimator is designed achromatic to the wave bands of two light sources of the interference ranging module and the absolute ranging module.
The utility model has the advantages that:
1. two beams of light are combined on the same optical fiber through a wavelength division multiplexing device and then output by a collimator, so that the condition of angle mismatch of the two beams of light is avoided.
2. Through the design of the optical system of the optical fiber, the stability only slightly influences the coupling efficiency, and the system failure can not be caused.
3. A new environment compensation scheme with a simple structure is provided.
Drawings
Fig. 1 is a schematic diagram of the present invention, which is a fiber laser ranging system.
Detailed Description
The present invention will be further described with reference to the following description and embodiments.
As shown in fig. 1, a fiber laser ranging system is mainly composed of two modules, i.e., an IFM module and an ADM module.
The IFM module 1 mainly includes a light source 11, a collimator 12, a circulator 13, a 1 × 2 beam splitter 15, an interference module 14, a reference module 16, and an optical fiber.
The ADM module 2 mainly includes a light source 21, a collimator 22, a circulator 23, a modulator 26, a measurement module 24, and an optical fiber.
The whole optical path system also comprises a WDM (wavelength division multiplexing) 3, a 1 multiplied by 2 optical switch 4, a compensation optical path and a measurement optical path.
The optical fiber, circulator 13, circulator 23, 1 × 2 splitter 15, WDM3, and 1 × 2 optical switch 4 described above are polarization maintaining optics.
The light source 11 of the IFM module 1 is coupled into the optical fiber by the collimator 12, the fast axis or slow axis direction of the polarization maintaining optical fiber must be aligned with the polarization direction of the light, and the polarization direction can be matched by rotating the collimator 12, and 1/2 wave plates can be added, and the polarization direction can be matched by rotating the wave plates. The optical fiber is then connected into the circulator 13, and the matching of the fast axis or the slow axis is also required to be ensured, or the circulator 13 and the collimator 12 are integrally processed, and a collimator lens is arranged at the input optical fiber of the circulator 12, so that the step of welding the tail optical fiber of the collimator and the fast and slow axis of the input optical fiber of the circulator in alignment can be omitted.
All the optical fibers referred to above must be polarization maintaining optical fibers, and the connection between the polarization maintaining optical fibers must ensure the alignment of the fast and slow axes, which is also referred to below and will not be described in detail.
The output end of the circulator 13 is connected to a 1 × 2 fiber splitter 15, one of which is used as a reference module, and the other is used as a measurement optical path and connected to the WDM3, and is combined with the ADM module 2. The returned light signal enters the interference module 14 through the circulator 13, and the measurement of the relative movement distance of the target is completed by detecting the intensity of the interference signal between the measurement light and the reference light.
The above-mentioned interference module 14 is based on a michelson interferometer, and the basic implementation scheme and various modifications thereof are disclosed in the prior art, and are not described herein again.
The splitting ratio of the 1 × 2 optical fiber splitter 4 is designed to ensure that the reference light and the measured light are substantially equal in intensity, and it is necessary to consider that insertion loss is introduced by a plurality of subsequent devices in the measurement light path.
The reference module 16 may be composed of a collimator, 1/4 wave plate, and a cube-corner mirror, wherein the crystal optic axis direction of the 1/4 wave plate is 45 ° to the fast axis or slow axis direction of the polarization maintaining fiber.
The reference module 16 may also be a wave plate connected with the optical fiber 1/4, and the end face of the wave plate is plated with a high-reflection film.
The light source 21 of the ADM module 2 is coupled into the fiber by the collimator 22, the fiber is connected into the circulator 23, the forward output end of the circulator 23 is connected into the collimator 25, and the parallel light is output and passes through the modulator 26, and then is coupled into the next collimator 27, the tail fiber of the collimator 27 is connected into the WDM, and is combined with the IFM module 1.
The circulator 23 is connected with the measuring module 24 at the reverse output end.
The measurement module 24 is composed of a collimator, a PBS, and a photodetector, and is used to measure the intensity of the optical signal in the specified polarization direction, and many documents have already described the principle of ADM and its implementation scheme in detail, and are not described here again.
The modulator 26 may be an electro-optical modulator; and an optical fiber waveguide modulator can be used, and a front collimator and a rear collimator are omitted, so that the optical fiber degree of the system is improved.
The collimators 22, 25 and 27 can be integrally processed with the connected devices, and the collimator lens is mounted at the tail fiber of the devices, so that the step of aligning and welding the tail fiber of the collimators and the fast and slow axes of the tail fiber of the devices is omitted.
The IFM and ADM modules select light sources with different wave bands, are coupled to the same optical fiber by WDM3 with corresponding wave bands and are connected into a 1 x 2 optical switch 4, wherein one output port is connected with a measuring optical path, and the other output port is connected with a compensating optical path.
The 1 × 2 optical switch 4 alternately switches on the measurement optical path and the compensation optical path at a certain timing, and the time duty ratio of each channel can be adjusted.
The above-mentioned measuring light path includes collimator 51, 1/4 wave plate 52 and reflector 53.
The collimator 51 is designed for achromatic wavelength bands of the two light sources IFM and ADM, so as to ensure consistency of collimation effect.
The 1/4 wave plate has a crystal optical axis direction 45 ° to the fast axis or slow axis direction of the polarization maintaining fiber, and adopts a broadband wave plate containing the wavebands of the two light sources IFM and ADM or a wave plate designed for the two wavebands.
The beam expander can be added behind the 1/4 wave plate to adjust the collimation distance, and the beam expander is designed for the wave bands of the IFM light source and the ADM light source in an achromatic mode. The beam expander is not limited to being behind the 1/4 waveplate.
The above-mentioned reflector 53 is mounted on the object to be measured as a measurement cooperation target.
The compensation light path can be composed of a collimator, an 1/4 wave plate and a reflector, such as the measurement light path.
The compensation optical path can also be an optical fiber 1/4 wave plate, and the end face of the compensation optical path is plated with a high reflection film.
The optical fiber lengths of the measuring optical path and the compensating optical path are as short as possible.
The optical fiber is easily interfered by environmental factors such as temperature, during the work of the distance measuring module, the distance measuring data obtained by the signal light returned by the compensating optical path contains the drift of the whole optical path caused by the environmental influence, and the influence of the environmental factors on the optical system can be eliminated by making a difference value between the data and the distance measuring data obtained by the signal light returned by the measuring optical path.
The utility model provides a pair of laser rangefinder system of fibre, compare with current laser tracker range finding technique, have following progress:
(1) the IFM and the ADM are coupled to the same optical fiber, so that the problems that the angles of two beams of light are separated and light spots are not overlapped at a measuring position during remote measurement are avoided;
(2) the processing difficulty of optical elements and mechanical structural parts is reduced; the installation and adjustment difficulty is reduced, and the efficiency is improved;
(3) even if the light source is deformed, the coupling efficiency of the collimator is slightly reduced, the lighting effect of the system is influenced, the distance measuring performance is not directly influenced, and the phenomenon that an IFM and ADM light beam separation system fails is avoided, so that the reliability of the system is improved;
(4) and a compensation light path is newly added, so that the environment adaptability of the system is improved.
The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.
Claims (4)
1. A fibered laser ranging system, comprising: the device comprises an interference distance measurement module, an absolute distance measurement module, a wavelength division multiplexing unit, a 1 x 2 optical switch, a measurement optical path and a compensation optical path, wherein the output ends of the interference distance measurement module and the absolute distance measurement module are respectively connected with the wavelength division multiplexing unit, the wavelength division multiplexing unit is coupled and connected to the 1 x 2 optical switch, one output port of the 1 x 2 optical switch is connected with the measurement optical path, and the other output port of the 1 x 2 optical switch is connected with the compensation optical path.
2. The fibered laser ranging system according to claim 1, wherein: the interference distance measuring module comprises a first light source, a first collimator, a first circulator, a 1 x 2 beam splitter, an interference module and a reference module, wherein the first light source is connected with the input end of the first circulator through the first collimator, the forward output end of the first circulator is connected with the 1 x 2 beam splitter, the reverse output end of the first circulator is connected with the interference module, one output port of the 1 x 2 beam splitter outputs reference light to the reference module, the other output port outputs measuring light to the wavelength division multiplexing unit and completes beam combination with the absolute distance measuring module, a returned light signal enters the interference module through the first circulator, and the measurement of the relative moving distance of a target is completed by detecting the intensity of an interference signal between the measuring light and the reference light.
3. The fibered laser ranging system according to claim 1, wherein: the absolute distance measuring module comprises a second light source, a second collimator, a second circulator, a modulator and a measuring module, wherein the second light source is connected with the input end of the second circulator through the second collimator, the forward output end of the second circulator is connected with the modulator, and the reverse output end of the second circulator is connected with the measuring module.
4. The fibered laser ranging system according to claim 3, wherein: the absolute distance measuring module further comprises a third collimator and a fourth collimator, the forward output end of the second circulator is connected to the third collimator to output parallel light, the parallel light passes through the modulator and then is coupled to the fourth collimator, and a tail fiber of the fourth collimator is connected to the wavelength division multiplexing unit to complete beam combination with the interference distance measuring module.
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| CN202120037949.4U CN214278411U (en) | 2021-01-07 | 2021-01-07 | Laser ranging system of optic fibre |
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| CN202120037949.4U CN214278411U (en) | 2021-01-07 | 2021-01-07 | Laser ranging system of optic fibre |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114838658A (en) * | 2020-12-25 | 2022-08-02 | 深圳市中图仪器股份有限公司 | Light path system for improving beam combination precision |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114838658A (en) * | 2020-12-25 | 2022-08-02 | 深圳市中图仪器股份有限公司 | Light path system for improving beam combination precision |
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