CN117406353A - Method for coupling space linearly polarized light and polarization maintaining fiber - Google Patents
Method for coupling space linearly polarized light and polarization maintaining fiber Download PDFInfo
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- CN117406353A CN117406353A CN202311502356.0A CN202311502356A CN117406353A CN 117406353 A CN117406353 A CN 117406353A CN 202311502356 A CN202311502356 A CN 202311502356A CN 117406353 A CN117406353 A CN 117406353A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
- G02B6/422—Active alignment, i.e. moving the elements in response to the detected degree of coupling or position of the elements
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/27—Optical coupling means with polarisation selective and adjusting means
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Abstract
The application relates to the technical field of angle measurement and transmission, and particularly provides a method for coupling spatially linearly polarized light and polarization maintaining optical fibers to shaft, which comprises the following steps: s1, fixing a polarization maintaining optical fiber to obtain an end face image; s2, determining the characteristic direction of the polarization maintaining optical fiber and the included angle between the characteristic direction and the horizontal direction by using the end surface image; s3, regulating the polarization direction of the incident polarized light, so that the polarization principal axis azimuth angle of the incident polarized light and the included angle between the characteristic direction of the polarization maintaining optical fiber and the horizontal direction are the same; s4, adjusting the height of the light source to be the same as the height of the polarization maintaining optical fiber, and finishing the shaft; s5, detecting the shaft aligning effect so as to ensure that shaft aligning is realized. The method provided by the invention is used for accurately detecting the polarization state, determining the characteristic direction at the end face of the polarization maintaining optical fiber, and adjusting the polarizer to enable the polarization direction of the incident laser to be consistent with the characteristic direction of the polarization maintaining optical fiber, so that the accuracy of a shaft is improved, and high-quality polarization maintaining transmission after the linearly polarized light is coupled into the polarization maintaining optical fiber is ensured.
Description
Technical Field
The application relates to the technical field of angle measurement and transmission, in particular to a method for coupling spatially linearly polarized light with polarization maintaining optical fibers.
Background
The polarization maintaining optical fiber is a special optical fiber with a double refraction main shaft, and has stronger polarization maintaining capability on linearly polarized light; when the polarization direction of incident light is precisely aligned with the fast axis or the slow axis of the polarization maintaining fiber, the linearly polarized light can keep the polarization state unchanged in the polarization maintaining fiber. For example, the non-through azimuth transfer technology based on the polarization maintaining optical fiber solves the problem of limitation that polarized light beams are not blocked by utilizing the high polarization maintaining performance and the anti-interference capability of the polarization maintaining optical fiber, and realizes high-precision transfer of azimuth information under the non-through condition. The non-viewing azimuth transfer device based on the polarization-preserving fiber consists of an upper instrument and a lower instrument, laser emitted by a laser in the upper instrument becomes linearly polarized light through a polarizer, the linearly polarized light carrying azimuth information of the polarizer is coupled into the polarization-preserving fiber and is transmitted to the lower instrument, and electric signals corresponding to azimuth angles are extracted through a modulator, an analyzer, a focusing mirror, photoelectric conversion, signal detection processing and the like, and rotation of the lower instrument is driven to complete azimuth synchronization, so that azimuth information transfer under a non-viewing condition is realized. When the linear polarized light carrying the azimuth information is coupled with the polarization maintaining fiber, when the polarization axis of the polarized light is not aligned with the fast axis or the slow axis of the polarization maintaining fiber, the polarization state of the polarized light after entering the polarization maintaining fiber changes, and the azimuth transmission precision of the system is seriously affected. Therefore, the precise alignment of the polarization axis of the space polarization light and the fast axis or the slow axis of the polarization maintaining fiber is a key technology for ensuring the azimuth transmission precision of the system.
Currently, the axis alignment method of free space light to polarization maintaining fiber coupling is mainly a power detection method. The invention discloses a device and a method for aligning shaft coupling from space light to polarization maintaining optical fiber, and the publication number is CN 110133804A. The accuracy of the axis of the method depends on the accuracy and the sensitivity of the detector of the power meter, the characteristic direction of the polarization maintaining fiber is not determined, and the accurate and visual axis of the method cannot be realized only by judging the light input and the light output of the polarization maintaining fiber.
In summary, the prior art has low axial precision, and affects the polarization transmission quality of polarized light in the polarization-maintaining fiber.
Disclosure of Invention
The invention aims to provide a method for coupling space linearly polarized light and polarization maintaining optical fiber to solve the problems that the prior art is low in axis accuracy and the polarization transmission quality of polarized light in the polarization maintaining optical fiber is affected.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the application provides a method for coupling spatially linearly polarized light and polarization maintaining fiber, which comprises the following steps:
s1, fixing a polarization maintaining optical fiber to obtain an end face image;
s2, determining the characteristic direction of the polarization maintaining optical fiber and the included angle between the characteristic direction and the horizontal direction by using the end surface image;
s3, regulating the polarization direction of the incident polarized light, so that the polarization principal axis azimuth angle of the incident polarized light and the included angle between the characteristic direction of the polarization maintaining optical fiber and the horizontal direction are the same;
s4, adjusting the height of the light source to be the same as the height of the polarization maintaining optical fiber, and finishing the shaft;
s5, detecting the shaft aligning effect so as to ensure that shaft aligning is realized.
Further, the step S1 comprises stripping the coating layers at two ends of the polarization maintaining optical fiber, and cutting the flat end face by using an optical fiber cutting knife; the polarization maintaining optical fiber is horizontally fixed on one end of the shaft; and acquiring an end face image of the polarization maintaining optical fiber by using an imaging microscope.
Further, step S2 includes performing image processing on the end face image of the polarization maintaining fiber, and marking the fast axis, the slow axis, and the horizontal reference direction of the polarization maintaining fiber to obtain an included angle between the fast axis or the slow axis and the horizontal reference direction.
Further, the polarization-maintaining optical fiber is a panda type polarization-maintaining optical fiber; the image processing includes the identification of end face circles and panda eye stress areas.
Further, the characteristic direction of the polarization maintaining fiber refers to the fast axis or the slow axis of the polarization maintaining fiber.
Further, the step S3 includes the steps of:
s31, detecting the polarization direction of incident polarized light;
s32, the polarization direction of the polarizer can be adjusted through rotation, so that the polarization direction of the incident polarized light is the same as the fast axis or slow axis direction of the polarization maintaining fiber.
Further, step S31 includes that the laser emitted from the laser source passes through the adjustable polarizer and enters the polarization state measuring instrument, and the polarization state measuring instrument detects the polarization direction of the laser.
Further, in step S31, the heights of the light source, the adjustable polarizer and the polarization state measuring device are the same and higher than the height of the polarization maintaining fiber.
Further, step S32 includes adjusting the adjustable polarizer, changing the polarization direction of the incident laser beam, slowly adjusting the adjustable polarizer, observing the display of the polarization state measuring instrument, and stopping rotation until the included angle between the polarization direction of the received laser beam and the horizontal direction is consistent with the included angle in step S2.
Further, step S4 includes adjusting the heights of the light source, the adjustable polarizer and the polarization maintaining fiber to be equal, and keeping the polarization angle of the adjustable polarizer unchanged, wherein the polarization maintaining fiber and the light source complete the axis alignment.
Compared with the prior art, the invention has the beneficial effects that: the method does not judge whether the shaft is accurate or not through power, extinction ratio and the like. The invention obtains the end face image of the polarization maintaining fiber through an imaging microscope, and utilizes image processing software to carry out algorithm calculation to determine the slow axis or fast axis direction of the polarization maintaining fiber and the included angle between the slow axis or fast axis direction and the horizontal direction; the polarization direction of the incident polarized light is received and observed through the polarization state measuring instrument, the polarizer is slowly adjusted, the main axis azimuth angle of the polarized light and the included angle between the fast axis or the slow axis of the polarization maintaining optical fiber and the horizontal direction are kept consistent, and the system is used for checking the shaft aligning effect through the polarization state measuring instrument. According to the method, the polarization state is accurately detected by using the polarization state measuring instrument, the characteristic direction at the end face of the polarization maintaining optical fiber is found by an image processing method, and the adjustable polarizer is adjusted to enable the polarization direction of incident laser to be consistent with the characteristic direction of the polarization maintaining optical fiber, so that the accuracy of a shaft is improved, and high-quality polarization maintaining transmission is ensured after linear polarized light is coupled into the polarization maintaining optical fiber.
Drawings
FIG. 1 is a schematic diagram of a method for coupling spatially linearly polarized light with polarization maintaining fiber according to the present invention;
FIG. 2 is a schematic diagram of an apparatus for imaging an end face of a polarization maintaining fiber by an imaging microscope in step S1 in a method for coupling spatially linearly polarized light with the polarization maintaining fiber according to the present invention;
FIG. 3 is an end image obtained in step S1 in a method for coupling spatially linearly polarized light with polarization maintaining fiber according to the present invention;
FIG. 4 is a schematic diagram of an image processing procedure in step S2 in a method of coupling spatially linearly polarized light with polarization maintaining fiber according to the present invention;
FIG. 5 shows the fast axis, the slow axis and the angles between the slow axis and the horizontal reference direction obtained in step S2 in a method for coupling spatially linearly polarized light and polarization maintaining fiber according to the present invention;
FIG. 6 is a schematic diagram showing the azimuth angle information of the polarization principal axis of the incident polarized light displayed by the polarization state measuring instrument in the step S3 in the method of coupling the spatially linearly polarized light and the polarization maintaining fiber according to the present invention;
fig. 7 is a schematic diagram showing polarization state information of an exit end of a polarization maintaining fiber displayed by a polarization state measuring instrument in step S5 in a method for coupling spatially linearly polarized light and the polarization maintaining fiber according to the present invention.
Detailed Description
In order to make the implementation of the present invention more clear, the following detailed description will be given with reference to the accompanying drawings.
The invention provides a method for coupling space linear polarized light and polarization maintaining optical fiber, which comprises the steps of determining an included angle between a fast axis or a slow axis of the polarization maintaining optical fiber and a horizontal direction and a polarization main axis azimuth angle of incident ray polarized light by means of an imaging microscope and a polarization state measuring instrument; the polarizer is further adjusted to enable the polarization main axis azimuth angle of the incident polarized light to be consistent with the included angle between the fast axis or the slow axis of the optical fiber and the horizontal direction; the method realizes the alignment of the space linearly polarized light and the polarization maintaining optical fiber, and can also use a polarization state measuring instrument to test the alignment effect of the system. The device used for the shaft mainly comprises a collimation laser source, an adjustable linear polarization polarizer, a CCD or CMOS imaging microscope, a polarization-preserving fiber (panda type) and a polarization state measuring instrument, and the panda type polarization-preserving fiber is taken as an example in the embodiment.
As shown in fig. 1, the method specifically comprises the following steps:
s1, fixing a polarization maintaining optical fiber to obtain an end face image;
and horizontally fixing the to-be-aligned polarization maintaining optical fiber, and then acquiring an end face image of the polarization maintaining optical fiber through an imaging microscope. Firstly, adjusting an optical fiber displacement table to a horizontal state as a direction reference; and taking the to-be-counter-shaft polarization maintaining optical fiber, removing the optical fiber cladding, stripping coating layers at two ends of the optical fiber by using a Muller clamp, and cutting to obtain a flat end face by using an optical fiber cutting knife, namely, the end face of the polarization maintaining optical fiber is perpendicular to the central axis of the polarization maintaining optical fiber. Then, one end of the polarization maintaining fiber to be aligned is fixed on the leveled fiber displacement table. Specifically, one end of the cut polarization maintaining optical fiber can be fixed on an optical fiber clamp, the end face of the polarization maintaining optical fiber is ensured to be smooth and clean, a small section of the polarization maintaining optical fiber is exposed, the polarization maintaining optical fiber is easy to bend due to overlong length, the optical fiber clamp is fixed on a leveled multi-degree-of-freedom optical fiber displacement table, so that shafts and photographing are facilitated, and when the shafts are aligned, the incident end face of the optical fiber is vertical to the horizontal direction. And cutting the two ends of the polarization maintaining optical fiber of the shaft.
And acquiring an end face image of the polarization maintaining optical fiber by using an imaging microscope, enabling the objective lens to be coaxial with the length direction of the polarization maintaining optical fiber, and acquiring the end face image of the polarization maintaining optical fiber, as shown in fig. 2. The end face of the polarization maintaining fiber forms a clear image in an imaging microscope. Specifically, a power switch of the imaging microscope is turned on, the focal length is adjusted to be minimum, the light source intensity of the imaging microscope is adjusted according to the brightness of the display, and the microscope platform is moved until the optical fiber appears in the field of view of the imaging microscope; then, gradually adjusting the focal length, and rotating an adjusting screw on the displacement table while amplifying the focal length, so that the end face of the optical fiber is kept at the middle part of the visual field while being amplified; when the focal length is large enough, the light source intensity is adjusted, the front-back distance is finely adjusted until a clear polarization maintaining optical fiber end structural surface is seen, and the image is stored. In this way, an end face image of the polarization maintaining fiber which is clear and located at the center can be obtained as shown in fig. 3. The stress region, core and cladding of the polarization maintaining fiber can be seen from the acquired image. After the photograph is obtained, the imaging microscope can be removed and the polarization maintaining fiber immobilized.
S2, determining the characteristic direction of the polarization maintaining optical fiber and the included angle between the characteristic direction and the horizontal direction by using the end surface image;
and determining the characteristic direction of the polarization maintaining optical fiber and the included angle between the characteristic direction and the horizontal direction by using image processing software aiming at the acquired end face image. The characteristic direction of the polarization maintaining fiber refers to the direction of the fast axis or the slow axis.
Specifically, processing the end face image of the polarization maintaining optical fiber, and marking a fast axis, a slow axis and a horizontal reference direction of the polarization maintaining optical fiber to obtain an included angle between the fast axis or the slow axis and the horizontal reference direction. In the embodiment, panda type polarization maintaining optical fiber is taken as an example, a panda eye (stress area) in an optical fiber image is identified by utilizing Pycham or other image processing software to process an end surface image of the polarization maintaining optical fiber, a circular shape is fitted, then the radius and the circle center of the panda eye circle are solved, the circle center is connected to draw a straight line, then a vertical line of the straight line is drawn, finally a fast axis or a slow axis and an included angle alpha between the slow axis and a horizontal reference are solved, specifically, the embodiment determines the direction of the slow axis of the optical fiber, and further determines the included angle alpha between the slow axis of the polarization maintaining optical fiber and the horizontal direction. The specific image processing process is as follows:
as shown in fig. 4, gray processing is performed on the obtained polarization maintaining fiber end face image, binarization is performed on the gray image, a pixel point larger than a threshold value is set as 225, and a pixel point lower than the threshold value is set as 0, so that a black-and-white clear image can be obtained, and the subsequent contour recognition is facilitated; in order to obtain the outline of the fiber-optic endface image, a slightly smaller threshold (first threshold) can be set to obtain a binarized fiber-optic endface circle; then fitting the end face circle to obtain a circle center and a radius, and extracting the end face circle by using an circumscribed rectangle; identifying panda eye stress areas of the optical fibers, setting a slightly larger threshold value (a second threshold value is larger than a first threshold value) for the gray end face image again, and performing binarization processing to obtain an image of panda eye outline; fitting the circles in the images to obtain the circle center position and the radius of the bear cat eye circle; finally, connecting circle centers of the two panda eyes to draw a slow axis, and drawing a vertical line with a connecting line to obtain a fast axis; and calculating the included angle between the fast axis and the slow axis and the direction reference, and adjusting the incident direction of incident linearly polarized light to realize axis fixing.
Generally, the identification difficulty of the panda eye stress area is greater than that of the end face circle due to the fact that the structure is more complex and the position is more accurate. In the method, the end face circle in the image is firstly identified and fitted, and then the panda eye stress area is identified and fitted, wherein the identification of the end face circle reduces the area range for the panda eye stress area, so that the panda eye stress area is easier, and the identification result is more accurate; the second threshold value for identifying the gray level of the panda eye stress area is larger than the first threshold value for identifying the gray level of the panda eye stress area when the end face is round, so that the distinction of the panda eye stress area is larger, the contrast ratio during identification is higher, and the panda eye stress area is easier to accurately identify; therefore, the method can accurately find the Xiong Maoyan stress area, so that the found fast and slow axes are accurate, the included angles between the fast and slow axes and the horizontal direction are more accurate, and finally the axis is accurate. The obtained images of the angles between the fast axis, the slow axis and the horizontal reference direction are shown in fig. 5.
S3, regulating the polarization direction of the incident polarized light, so that the polarization principal axis azimuth angle of the incident polarized light and the included angle between the characteristic direction of the polarization maintaining optical fiber and the horizontal direction are the same;
s31, detecting the polarization direction of incident polarized light;
and measuring the polarization state of the incident ray polarized light by a polarization state measuring instrument to obtain the azimuth angle of the polarization principal axis of the incident polarized light. On the horizontal plane, a laser source and an adjustable polarizer are fixedly arranged at one end of the polarization maintaining optical fiber, the adjustable polarizer is fixedly arranged between the laser source and the polarization maintaining optical fiber, and the direction of laser emitted by the laser source is parallel to the central axis direction of the polarization maintaining optical fiber. One end of the polarization maintaining optical fiber, which is far away from the adjustable polarizer, is fixedly provided with a polarization state measuring instrument, and the polarization state measuring instrument can detect the polarization state of incident laser.
The laser emitted by the laser source, the polarization direction of the adjustable polarizer, the central axis of the polarization maintaining optical fiber and the normal direction of the light receiving port of the polarization state measuring instrument are all in the same plane, and the plane is vertical to the horizontal plane. In order to detect the polarization state of laser light, the heights of the laser source, the adjustable polarizer and the polarization state measuring instrument are the same and higher than the height of the polarization maintaining optical fiber, so that the light emitted by the light source can enter the polarization state measuring instrument after passing through the adjustable polarizer to detect the polarization state.
And collecting the linearly polarized light emitted by the adjustable polarizer through a polarization state measuring instrument to obtain the azimuth angle of the polarization main axis. And obtaining the azimuth angle of the polarization principal axis of the emergent polarized light by the elliptical parameter of the polarized light in the display connected with the polarization state detector. Specifically, the light intensity of the laser is adjusted from small to large, so that the light intensity can just emit visible laser, the laser emitted by the laser source passes through the adjustable polarizer, the polarization state of the incident laser becomes a specific direction (the polarization direction of the adjustable polarizer), and the incident laser enters the polarization state measuring instrument to be detected, so that the polarization main axis azimuth angle of the polarized light is obtained. When the polarization state tester is used, the polarization state tester is started to preheat for ten minutes, a program is initialized after the preheating is finished, the polarization state of incident polarized light is measured, the connected display can display elliptical parameters of the polarized light, and the azimuth angle of the polarization main axis of the polarized light is obtained, namely, the direction of a slow axis (or a fast axis) and the included angle between the slow axis and the horizontal direction are obtained.
S32, the polarization direction of the adjustable polarizer is adjusted, so that the polarization direction of the incident polarized light is consistent with the fast axis or slow axis direction of the polarization maintaining fiber.
And (2) adjusting the polarizer, namely changing the polarization direction of the incident laser, slowly adjusting the polarizer, observing the display of the polarization state measuring instrument, and stopping rotating until the polarization direction of the received laser is consistent with the fast axis or slow axis direction of the polarization maintaining optical fiber and the included angle in the step S2. That is, rotating the adjustable polarizer changes the polarization direction of the laser exiting the adjustable polarizer, thereby changing the polarization state of the incident laser of the polarization maintaining fiber. When the polarization direction of the adjustable polarizer is regulated, the display of the polarization state measuring instrument is observed, and when the included angle between the polarization direction of the received laser and the horizontal direction is alpha, the rotation is stopped, namely, the azimuth angle of the main axis of the incident light is regulated to alpha, at the moment, the polarization direction of the incident laser and the direction of the slow axis of the polarization maintaining optical fiber tend to be consistent, and the polarization maintaining performance is best during incident coupling. The polarization state measuring instrument displays information of the polarization principal axis azimuth angle of the incident polarized light as shown in fig. 6.
S4, adjusting the height of the light source to be the same as the height of the polarization maintaining optical fiber, and finishing the shaft;
the heights of the light source and the adjustable polarizer are adjusted to be equal to the height of the polarization maintaining optical fiber, the polarization angle of the adjustable polarizer is kept unchanged, and the polarization maintaining optical fiber and the light source are completed in a coaxial way. The polarization direction of the light emitted by the light source is the same as the polarization angle of the adjustable polarizer, the polarization direction of the polarized light transmitted through the adjustable polarizer is consistent with the slow axis direction of the polarization maintaining fiber, and after the light is coupled into the polarization maintaining fiber, the polarization state of the light transmitted in the polarization maintaining fiber is kept unchanged, so that high-quality polarization maintaining transmission is realized.
S5, detecting the shaft aligning effect so as to ensure that shaft aligning is realized.
The polarization state measuring instrument is used for detecting the shaft effect, so that the shaft effect is ensured. The heights of the laser source, the polarizer and the polarization state measuring instrument are adjusted to be consistent with the polarization maintaining fiber. The laser is changed into linearly polarized light through a polarizer and is coupled into a polarization maintaining fiber, based on the steps, the polarization direction of the polarized light is consistent with the fast axis or the slow axis direction of the polarization maintaining fiber, polarization maintaining transmission is carried out in the polarization maintaining fiber, the laser emitted by the polarization maintaining fiber is detected through a polarization state measuring instrument, and the polarization ellipse is displayed as linearly polarized light under the condition that the polarization maintaining fiber is not influenced by other external force, temperature and other external factors; if the display is circularly polarized light or elliptically polarized light, the axis is inaccurate, and the polarizer can be repeatedly adjusted within a small range for many times until the display of the polarization state measuring instrument is linearly polarized light, so that the display of the axis polarization state measuring instrument is finished as shown in fig. 7.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method of aligning spatially linearly polarized light coupled to a polarization maintaining fiber, the method comprising the steps of:
s1, fixing a polarization maintaining optical fiber to obtain an end face image;
s2, determining the characteristic direction of the polarization maintaining optical fiber and the included angle between the characteristic direction and the horizontal direction by using the end surface image;
s3, regulating the polarization direction of the incident polarized light, so that the polarization principal axis azimuth angle of the incident polarized light and the included angle between the characteristic direction of the polarization maintaining optical fiber and the horizontal direction are the same;
s4, adjusting the height of the light source to be the same as the height of the polarization maintaining optical fiber, and finishing the shaft;
s5, detecting the shaft aligning effect so as to ensure that shaft aligning is realized.
2. The method for coupling spatially linearly polarized light to polarization maintaining fiber according to claim 1, wherein the step S1 comprises peeling off the coating layers at both ends of the polarization maintaining fiber and cutting out a flat end surface using a fiber cutter; the polarization maintaining optical fiber is horizontally fixed at one end of the shaft; and acquiring an end face image of the polarization maintaining optical fiber by using an imaging microscope.
3. The method according to claim 2, wherein the step S2 includes performing image processing on the end face image of the polarization maintaining fiber, and marking the fast axis, the slow axis, and the horizontal reference direction of the polarization maintaining fiber to obtain the included angle between the fast axis or the slow axis and the horizontal reference direction.
4. The method for coupling spatially linearly polarized light to a polarization maintaining fiber according to claim 3, wherein the polarization maintaining fiber is a panda type polarization maintaining fiber; the image processing includes the identification of end face circles and panda eye stress areas.
5. The method of aligning spatially linearly polarized light with a polarization maintaining fiber according to claim 4, wherein the characteristic direction of the polarization maintaining fiber is a fast axis or a slow axis of the polarization maintaining fiber.
6. The method for coupling spatially linearly polarized light to polarization maintaining fiber according to claim 1 or 5, wherein the step S3 comprises the steps of:
s31, detecting the polarization direction of incident polarized light;
s32, the polarization direction of the polarizer can be adjusted through rotation, so that the polarization direction of the incident polarized light is the same as the fast axis or the slow axis direction of the polarization maintaining fiber.
7. The method of aligning coupling of spatially linearly polarized light and polarization maintaining fiber according to claim 6, wherein the step S31 comprises passing the laser light from the laser light source through the adjustable polarizer and then entering the polarization state measuring instrument, and the polarization state measuring instrument detects the polarization direction of the laser light.
8. The method according to claim 7, wherein the heights of the light source, the adjustable polarizer, and the polarization state measuring instrument in the step S31 are the same and higher than the height of the polarization maintaining fiber.
9. The method of aligning coupling of spatially linearly polarized light with polarization maintaining fiber according to claim 8, wherein the step S32 comprises adjusting the adjustable polarizer, changing the polarization direction of the incident laser light, slowly adjusting the adjustable polarizer, and observing the display of the polarization state measuring instrument until the angle between the polarization direction of the received laser light and the horizontal direction and the angle in the step S2 tend to be consistent, and stopping the rotation.
10. The method of aligning coupling of spatially linearly polarized light with polarization maintaining fiber according to claim 9, wherein the step S4 comprises adjusting the heights of the light source, the adjustable polarizer and the polarization maintaining fiber to be equal and keeping the polarization direction of the adjustable polarizer unchanged, and the polarization maintaining fiber and the light source complete alignment.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311502356.0A CN117406353A (en) | 2023-11-13 | 2023-11-13 | Method for coupling space linearly polarized light and polarization maintaining fiber |
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| CN202311502356.0A CN117406353A (en) | 2023-11-13 | 2023-11-13 | Method for coupling space linearly polarized light and polarization maintaining fiber |
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