Method and device for determining laser pointing angle of fiber laser

Abstract

One technical solution of the present invention is to provide a method for determining the output laser pointing angle of a fiber laser. Another technical solution of the present invention is to provide a device for determining the output laser pointing angle of a fiber laser. The reason why the pointing angle is difficult to measure is that it is necessary to ensure the strict parallelism between the fixed surface of the output head and the light spot receiving surface. In addition, it is difficult to find the focus of the central axis of the output head and the light spot receiving surface. Relatively speaking, it is relatively easy to ensure the parallelism between the fixed surface of the output head and the light spot receiving surface. In the present invention, through the structure of the rotation of the plane mirror, the light emitting point is also the center point of the ideal light spot. At the same time, the present invention uses an up-conversion chip and marks scales on the up-conversion chip, so that the trajectory of the light spot can be directly observed, and it can be judged whether the pointing angle performance meets the requirements.

Description

Technical Field

[0001] The present invention relates to a determination device for the output laser pointing angle of a fiber laser and a method for determining the output laser pointing angle of a fiber laser using the determination device. Background Art

[0002] Fiber lasers mainly have two major application fields: military and industrial. Militarily, it is required that the output laser of the fiber laser has excellent pointing angle performance. It can be imagined that if the output laser has poor directivity, it will be difficult for the laser to hit the target. Industrially, the requirement for the pointing angle performance of the output laser is not as high as that for military applications. However, according to the common knowledge of those skilled in the art, fiber lasers in industrial applications are used in combination with equipment such as cutting heads and welding heads. If the pointing angle performance of the output laser is too poor, the laser will not be able to safely pass through the cutting head or welding head, resulting in poor application effects at best and burning of the cutting head or welding head at worst.

[0003] The fiber laser has an all-fiber structure. However, due to the too high energy density of the final laser, it cannot be directly output from the fiber. It is necessary to fuse a quartz end cap at the end of the output fiber to expand the laser for safe output. The quartz end cap part will be mechanically encapsulated to form an output head in a certain interface form, such as QBH, QD, Q+, etc. During use, the output head needs to be locked with the terminal device for light output operation. As can be seen above, during the fusion process of the fiber and the quartz end cap, as well as the mechanical encapsulation process of the quartz end cap, the pointing angle performance of the final output laser will deteriorate.

[0004] Currently, in the industrial processing field, it is required that the pointing angle of the output laser of the fiber laser is at the mrad level, and in the military weapon field, a smaller pointing angle is required. This makes the measurement of the output laser pointing angle difficult and inconvenient, and there is no standardized measurement method in the industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention: Currently, the measurement of the output laser pointing angle is difficult and inconvenient.

[0006] To solve the above technical problem, a technical solution of the present invention is to provide a method for determining the output laser pointing angle of a fiber laser, which is characterized by including the following steps:

[0007] Step 1: Set an upconversion chip, and set a plane mirror above the upconversion chip. Among them, there is a through hole at the center position of the upconversion chip, and its upper surface is marked with a plurality of concentric circles with different radii R, and the center of the concentric circles is the center of the upconversion chip;

[0008] Step 2: The output head of the fiber laser dedicated for calibration emits laser through the through-hole from below the upconversion chip towards the plane mirror. The laser hits the plane mirror through the through-hole and is reflected onto the upconversion chip, thus forming a light spot on the upconversion chip.

[0009] Step 3: Rotate the plane mirror 360° along its own axis. During the rotation, observe whether the position of the light spot on the upconversion chip changes. If it changes, it means that the plane mirror and the upconversion chip are not parallel, and proceed to Step 4. If it does not change, it means that the plane mirror and the upconversion chip are parallel, and proceed to Step 5.

[0010] Step 4: After making the plane mirror and the upconversion chip parallel to each other, return to Step 3 for re-detection.

[0011] Step 5: According to the performance requirements for the pointing angle of the laser output by the fiber laser, calculate the maximum radius of the area that the light spot trajectory can cover. Based on the maximum radius and the concentric circles with different radii R marked on the upconversion chip, determine the corresponding concentric circle marks on the upconversion chip.

[0012] Step 6: The output head of the fiber laser to be tested emits laser through the through-hole from below the upconversion chip towards the plane mirror. The laser is reflected by the plane mirror and hits the upconversion chip to form a light spot. If there is an area of the light spot that exceeds the concentric circle marks determined in Step 5, it is considered that the pointing angle performance of the laser output by the fiber laser to be tested does not meet the requirements. Otherwise, it is considered that the pointing angle performance of the laser output by the fiber laser to be tested meets the requirements.

[0013] Another technical solution of the present invention is to provide a determination device for the pointing angle of the laser output by a fiber laser, which is characterized in that it includes:

[0014] A base with a horizontal upper surface, and a through-hole one on the base;

[0015] An upconversion chip with a through-hole two in the center, and multiple concentric circles with different radii R are marked on the upper surface of the upconversion chip. The center of the concentric circles is the center of the upconversion chip. The upconversion chip is fixed on the upper surface of the base, and its through-hole two overlaps with the through-hole one on the base to form a through-hole. The upconversion chip remains horizontal;

[0016] A plane mirror that can rotate 360° around its own axis and is located above the upconversion chip. The laser output by the output head of the fiber laser passes through the through-hole and hits the plane mirror, and then is reflected by the plane mirror onto the upconversion chip, thus forming a light spot on the upper surface of the upconversion chip.

[0017] Preferably, the determination device further includes a bracket for fixing the plane mirror on the base.

[0018] Preferably, the determination device further includes an adapter, and the output head of the fiber laser is locked to the adapter. By designing the position of the adapter, the virtual light spot of the output head of the fiber laser is located on the up-conversion chip and at the center of the through hole.

[0019] The reason why the pointing angle is difficult to measure is that it is necessary to ensure the strict parallelism between the fixed surface of the output head and the light spot receiving surface. In addition, it is difficult to find the focus of the central axis of the output head and the light spot receiving surface. Relatively speaking, it is easier to ensure the parallelism between the fixed surface of the output head and the light spot receiving surface. In the present invention, through the structure of the rotation of the plane mirror, the light spot is also the center point of the ideal light spot. At the same time, the present invention uses an up-conversion chip and marks scales on the up-conversion chip, so that the trajectory of the light spot can be directly observed, and it can be judged whether the pointing angle performance meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the front view of the present invention;

[0021] Figure 2 is the partial top view of the present invention;

[0022] Figure 3 is the schematic diagram of the working principle of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0024] As Figure 1 shown, a determination device for the output laser pointing angle of a fiber laser disclosed by the present invention includes a panel 1, an up-conversion chip 2, an adapter 3, a bracket 4, a plane mirror 5 and table legs 6.

[0025] The up-conversion chip 2 and the adapter 3 are respectively fixed on the upper surface and the lower surface of the panel 1. The up-conversion chip 2 can directly observe the light spot of the laser with the corresponding wavelength. The output head of the fiber laser is locked to the adapter 3. The panel 1 and the up-conversion chip 2 have overlapping through holes, and the aperture of the through hole ensures that the laser emitted by the fiber laser can pass through. There is a bracket 4 on the panel 1, and the plane mirror 5 is installed on the bracket 4. The plane mirror 5 needs to be parallel to the panel 1, and at the same time, the plane mirror 5 can rotate horizontally by 360°.

[0026] As Figure 3As shown in the figure, after the laser exits from the output head, it is reflected by the plane mirror 5 and then hits the up-conversion chip 2. In an ideal state, the pointing angle of the laser output from the output head is zero. When the laser hits the up-conversion chip 2, the area covered by its spot trajectory is a concentric circle with the through-hole. The radius of the concentric circle is related to the divergence angle of the laser and the distance H between the up-conversion chip 2 and the panel 5. However, in actual situations, the pointing angle of the laser output from the output head is not zero. When the laser hits the up-conversion chip 2, the center of the circle formed by the area covered by its spot trajectory deviates from the axis of the through-hole. The magnitude of the pointing angle can be deduced based on the degree of deviation between the center of the circle formed by the area covered by the spot trajectory and the axis of the through-hole.

[0027] In the present invention, by designing the position of the adapter 3, the virtual light-emitting point of the output head of the fiber laser is located on the up-conversion chip 2 and at the center of the through-hole. The center of the through-hole is the center of the up-conversion chip 2. Taking the center of the up-conversion chip 2 as the center of the concentric circle, concentric circles with different radii R are marked on the up-conversion chip 2.

[0028] During actual use, it includes the following steps:

[0029] Step 1: Detect the parallelism of the plane mirror 5:

[0030] Lock the output head of the fiber laser dedicated for calibration on the adapter 3. After the laser emitted by the output head is reflected by the plane mirror 5, a spot is formed on the up-conversion chip 2. Rotate the plane mirror 5 horizontally by 360°. During the rotation process, observe whether the position of the spot on the up-conversion chip 2 changes. If it changes, it means that the plane mirror 5 and the up-conversion chip 2 are not parallel, and enter Step 2. If it does not change, it means that the plane mirror 5 and the up-conversion chip 2 are parallel, and enter Step 3.

[0031] Step 2: After leveling the plane mirror 5 and the up-conversion chip 2, return to Step 1 for re-detection.

[0032] Step 3: According to the performance requirements for the pointing angle of the laser output by the fiber laser, calculate the maximum radius of the area that the spot trajectory can cover. Based on the maximum radius and the concentric circles with the same radius R marked on the up-conversion chip 2, determine the corresponding concentric circle marks on the up-conversion chip 2;

[0033] Step 4: Lock the output head of the fiber laser to be tested on the adapter 3. After the laser emitted by the output head is reflected by the plane mirror 5, a spot is formed on the up-conversion chip 2. If there is an area of the spot that exceeds the concentric circle marks determined in Step 3, it is considered that the pointing angle performance of the laser output by the fiber laser to be tested does not meet the requirements. Otherwise, it is considered that the pointing angle performance of the laser output by the fiber laser to be tested meets the requirements.

Claims

1. A method for determining the output laser pointing angle of an optical fiber laser, characterized in that, It includes the following steps: Step 1: Set up a upconversion chip, and set a plane mirror above the upconversion chip. Among them, there is a through hole at the center position of the upconversion chip, and its upper surface is marked with multiple concentric circles with different radii R. The center of the concentric circles is the center of the upconversion chip; Step 2: The output head of the fiber laser dedicated for calibration emits laser from below the upconversion chip through the through hole towards the plane mirror. The laser passes through the through hole and hits the plane mirror and then is reflected back to the upconversion chip, thereby forming a light spot on the upconversion chip; Step 3: Rotate the plane mirror 360° along its own axis. During the rotation, observe whether the position of the light spot on the upconversion chip changes. If it changes, it means that the plane mirror and the upconversion chip are not parallel, and enter Step 4. If it does not change, it means that the plane mirror and the upconversion chip are parallel, and enter Step 5; Step 4: After making the plane mirror and the upconversion chip parallel to each other, return to Step 3 to re-detect; Step 5: According to the performance requirements for the pointing angle of the laser output by the fiber laser, calculate the maximum radius of the area that the light spot trajectory can cover. Based on the maximum radius and the concentric circles with different radii R marked on the upconversion chip, determine the corresponding concentric circle marks on the upconversion chip; Step 6: The output head of the fiber laser to be tested emits laser from below the upconversion chip through the through hole towards the plane mirror. The laser is reflected by the plane mirror and hits the upconversion chip to form a light spot. If there is an area of the light spot that exceeds the concentric circle marks determined in Step 5, it is considered that the pointing angle performance of the laser output by the fiber laser to be tested does not meet the requirements. Otherwise, it is considered that the pointing angle performance of the laser output by the fiber laser to be tested meets the requirements.

2. A determination device for the output laser pointing angle of a fiber laser, characterized in that, It includes: A base with a horizontal upper surface, and there is a through hole 1 on the base; A upconversion chip with a through hole 2 at the center. The upper surface of the upconversion chip is marked with multiple concentric circles with different radii R. The center of the concentric circles is the center of the upconversion chip; the upconversion chip is fixed on the upper surface of the base, and its through hole 2 overlaps with the through hole 1 on the base to form a through hole; the upconversion chip remains horizontal; A plane mirror that can rotate 360° around its own axis and is located above the upconversion chip; the laser output by the output head of the fiber laser passes through the through hole and hits the plane mirror, and then is reflected by the plane mirror to the upconversion chip, thereby forming a light spot on the upper surface of the upconversion chip; An adapter, the output head of the fiber laser is locked to the adapter. By designing the position of the adapter, the virtual light-emitting point of the output head of the fiber laser is located on the upconversion chip and at the center of the through hole.

3. The determination device for the output laser pointing angle of an optical fiber laser according to claim 2, characterized in that, The determination device further includes a bracket for fixing the plane mirror on the base.

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