A disc type high power optical isolator

Abstract

The utility model relates to a kind of disc type high-power optical isolator, it is characterized by: including sequentially arranged input optical fiber collimator, first light beam splitter, rotary vane, magneto-optic crystal and second light beam splitter, the outer surface of the magneto-optic crystal is attached with the first heat conduction sheet and second heat conduction sheet for the heat export of magneto-optic crystal, first heat conduction sheet is equipped with first magnet array relative to the side of magneto-optic crystal far away, second heat conduction sheet is equipped with second magnet array relative to the side of magneto-optic crystal far away;The input optical fiber collimator is used to input laser;First light beam splitter and second light beam splitter are used to divide a beam of light into p polarized light and s polarized light, or p polarized light and s polarized light are combined into a beam of light;The utility model disc type high-power optical isolator is conducive to quickly leading away the heat generated after magneto-optic crystal absorbs laser, thereby being conducive to reducing the thermal lens effect and thermal birefringence effect of magneto-optic crystal.

Description

Technical Field

[0001] This utility model relates to the field of laser technology, and in particular to a disc-type high-power optical isolator. Background Technology

[0002] In the field of high-power laser processing, the power requirements for laser processing equipment are getting higher and higher, with many requiring levels of approximately kilowatts or more. For fiber lasers in laser processing equipment, power outputs of more than kilowatts are not a problem, but for high-power optical isolators in laser processing equipment, it is a great challenge.

[0003] Among the current high-power optical isolators, the core magneto-optical crystal is the most difficult to withstand high power. Since the magneto-optical crystal has a certain absorption of laser light, it will heat up after absorbing the high-power laser light that has been transmitted, which will bring about thermal lensing effect and thermal light refraction effect. As a result, the quality of the laser beam output by the laser processing equipment will deteriorate, leading to a significant reduction in processing quality and efficiency. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a disk-type high-power optical isolator, which is conducive to quickly dissipating the heat generated after the magneto-optical crystal absorbs laser light, thereby helping to reduce the thermal lensing effect and thermal birefringence effect of the magneto-optical crystal.

[0005] The technical solution adopted in this utility model is as follows:

[0006] This utility model relates to a disk-type high-power optical isolator, characterized in that it comprises, in sequence, an input fiber collimator, a first optical beam splitter, a rotating plate, a magneto-optical crystal, and a second optical beam splitter. The outer surface of the magneto-optical crystal is fitted with a first heat-conducting plate and a second heat-conducting plate for heat conduction. A first magnet array is located on the side of the first heat-conducting plate opposite to the magneto-optical crystal, and a second magnet array is located on the side of the second heat-conducting plate opposite to the magneto-optical crystal. The input fiber collimator is used to input laser light. The first and second optical beam splitters are used to split a beam of light into p-polarized light and s-polarized light, or to combine p-polarized light and s-polarized light into a single beam. The rotating plate is used to perform a 45-degree reciprocal polarization rotation on the input laser light. The first and second magnet arrays provide a magnetic field for the magneto-optical crystal. The magneto-optical crystal has a disk-type structure for performing a 45-degree non-reciprocal polarization rotation on the input laser light. The surface area of ​​the magneto-optical crystal in contact with the heat-conducting plate is much larger than the area of ​​its side surfaces, causing the laser light to reflect back and forth between the two surfaces more than twice.

[0007] Preferably, the first heat-conducting sheet is bonded to the upper surface of the magneto-optical crystal and covers all surfaces except for the laser inlet and laser outlet of the upper surface of the magneto-optical crystal, and the second heat-conducting sheet is bonded to the lower surface of the magneto-optical crystal, with an area greater than or equal to that of the lower surface of the magneto-optical crystal.

[0008] Preferably, the first heat-conducting sheet is bonded to the lower surface of the magneto-optical crystal and covers all surfaces except for the laser inlet and laser outlet of the lower surface of the magneto-optical crystal, and the second heat-conducting sheet is bonded to the upper surface of the magneto-optical crystal, with an area greater than or equal to that of the upper surface of the magneto-optical crystal.

[0009] Preferably, the first and second heat-conducting sheets are bonded to the magneto-optical crystal by adhesive bonding.

[0010] Preferably, the rotating plate is a half-wave plate, and the magneto-optical crystal is made of TGG, TSAG, or bismuth-iron garnet.

[0011] Preferably, the first and second heat-conducting sheets are non-diamagnetic materials with high thermal conductivity and a refractive index lower than that of the magneto-optical crystal.

[0012] Preferably, the materials of the first and second heat-conducting sheets are iron-doped aluminum nitride, YAG, sapphire, or ruby.

[0013] Preferably, the optical axes of the input fiber collimator, the first optical beam splitter, and the rotating plate are inclined to the upper surface of the magneto-optical crystal; the inclination angle is 20-70 degrees.

[0014] Preferably, the combination of the rotating plate and the magneto-optical crystal is used to perform a 90-degree polarization rotation on the input light, while not performing a polarization rotation on the light transmitted in the opposite direction.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: by using a disc-shaped magneto-optical crystal with an upper and lower surface area much larger than its side surface area, and attaching a non-diamagnetic heat-conducting sheet with high thermal conductivity and a refractive index lower than that of the magneto-optical crystal to the upper and lower surfaces of the magneto-optical crystal, the heat generated by the magneto-optical crystal after absorbing laser light can be quickly conducted away by the first and second heat-conducting sheets, thereby significantly reducing the thermal lensing effect and thermally induced birefringence effect of the magneto-optical crystal, improving the laser beam quality, and making it suitable for use in kilowatt-level or higher high-power laser processing equipment. Attached Figure Description

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a side view of an embodiment of the present utility model. Figure 2 This is a top view schematic diagram of the forward light transmission structure according to an embodiment of the present invention;

[0017] Figure 3 This is a top view schematic diagram of the reverse light transmission structure according to an embodiment of the present invention. Detailed Implementation

[0018] like Figure 1 As shown, the disk-type high-power optical isolator includes: an input fiber collimator 1, a first optical beam splitter 2, a rotating plate 3, a magneto-optical crystal 4, and a second optical beam splitter 5 arranged in sequence, and a first heat-conducting plate 6, a second heat-conducting plate 7, a first magnet array 8, and a second magnet array 9 disposed above and below the magneto-optical crystal 4; the input fiber collimator 1 is used to input laser light; the first optical beam splitter 2 and the second optical beam splitter 5 are used to split light into p-polarized light and s-polarized light or to combine p-polarized light and s-polarized light into a single beam; the rotating plate 3 is used to perform a 45-degree reciprocal polarization rotation on the input laser light.

[0019] The magneto-optical crystal 4 has a disk-like structure, with the area of ​​its upper and lower surfaces being much larger than the area of ​​its sides. The laser light is reflected back and forth between its upper and lower surfaces. The magneto-optical crystal 4 is used to perform a 45-degree non-reciprocal polarization rotation on the input laser light. The combination of the rotating plate 3 and the magneto-optical crystal 4 is used to perform a 90-degree polarization rotation on the input light, while not performing polarization rotation on the light transmitted in the opposite direction.

[0020] The first heat-conducting sheet 6 and the second heat-conducting sheet 7 are respectively attached to the upper and lower surfaces of the magneto-optical crystal 4 (they can be bonded together with adhesive) to dissipate heat from the magneto-optical crystal 4. The first heat-conducting sheet 6 is attached to the upper surface of the magneto-optical crystal 4 and covers all surfaces except the laser inlet and laser outlet of the upper surface of the magneto-optical crystal 4. The second heat-conducting sheet 7 is attached to the lower surface of the magneto-optical crystal 4, and its area is greater than or equal to that of the lower surface of the magneto-optical crystal 4. Alternatively, the first heat-conducting sheet 6 is attached to the lower surface of the magneto-optical crystal 4 and covers all surfaces except the laser inlet and laser outlet of the lower surface of the magneto-optical crystal 4. The second heat-conducting sheet 7 is attached to the upper surface of the magneto-optical crystal 4, and its area is greater than or equal to that of the upper surface of the magneto-optical crystal 4. The first magnet array 8 and the second magnet array 9 are permanent magnets used to provide a magnetic field for the magneto-optical crystal 4.

[0021] The optical axes of the input fiber collimator 1, the first optical beam splitter 2, and the rotating plate 3 are inclined to the upper or lower surface of the magneto-optical crystal 4; the inclination angle is 20-70 degrees.

[0022] The rotating plate 3 is a half-wave plate, and the magneto-optical crystal 4 is made of TGG, TSAG, or bismuth iron garnet, etc. The first heat-conducting plate 6 and the second heat-conducting plate 4 are non-diamagnetic materials with high thermal conductivity and refractive index lower than that of the magneto-optical crystal, such as the first heat-conducting plate 6 and the second heat-conducting plate 7 being made of iron-doped aluminum nitride, YAG, sapphire, or ruby.

[0023] like Figure 1 , 2 As shown, for a forward-passing optical path, the collimated laser emitted by the input fiber collimator 1 is split into p-polarized light and s-polarized light after passing through the first optical beam splitter 2:

[0024] For p-polarized light, it passes directly through and is incident on the rotating plate 3. It is rotated 45 degrees clockwise by the rotating plate 3 and then incident on the laser inlet on the upper surface of the magneto-optical crystal 4. It is then refracted into the interior of the magneto-optical crystal 4 and reflected back and forth between the upper and lower surfaces of the magneto-optical crystal 4. Finally, it is emitted from the laser outlet on the upper surface of the magneto-optical crystal 4. During the transmission inside the magneto-optical crystal 4, under the combined action of the first magnet array 8 and the second magnet array 9, the polarization direction is further rotated 45 degrees clockwise. That is, the laser emitted from the laser outlet becomes s-polarized light, which is then reflected and output by the second beam splitter 5.

[0025] For s-polarized light, it is reflected by the first beam splitter 2 and incident on the rotating plate 3. The rotating plate 3 rotates it 45 degrees clockwise and then it is incident on the laser inlet on the upper surface of the magneto-optical crystal 4. It is then refracted into the interior of the magneto-optical crystal 4 and reflected back and forth between the upper and lower surfaces of the magneto-optical crystal 4. Finally, it is emitted from the laser outlet on the upper surface of the magneto-optical crystal 4. During the transmission inside the magneto-optical crystal 4, under the combined action of the first magnet array 8 and the second magnet array 9, the polarization direction is further rotated 45 degrees clockwise. That is, the laser emitted from the laser outlet becomes p-polarized light and is then transmitted by the second beam splitter 5. The reflected s-polarized light and the transmitted p-polarized light are finally combined into a single laser beam for output.

[0026] like Figure 3 As shown, for a reverse-transmission optical path, light entering from the outside is first split into p-polarized light and s-polarized light by the second beam splitter 5:

[0027] For p-polarized light, it passes directly through the second optical beam splitter 5 and then enters the laser exit point on the upper surface of the magneto-optical crystal 4. It is then refracted into the interior of the magneto-optical crystal 4 and reflected back and forth between the upper and lower surfaces of the magneto-optical crystal 4. Finally, it exits from the laser entrance on the upper surface of the magneto-optical crystal 4. During its transmission inside the magneto-optical crystal 4, the polarization direction is rotated counterclockwise by 45 degrees under the combined action of the first magnet array 8 and the second magnet array 9. Then, it enters the rotating plate 3, where the polarization direction is rotated clockwise by 45 degrees, returning to p-polarized light. Finally, it enters the first optical beam splitter 2 and is directly transmitted through it, thus preventing it from returning to the input fiber collimator and realizing the function of an isolator.

[0028] For s-polarized light, it is first reflected by the second beam splitter 5, then incident on the laser exit point on the upper surface of the magneto-optical crystal 4, and then refracted into the interior of the magneto-optical crystal 4. It is then reflected back and forth between the upper and lower surfaces of the magneto-optical crystal 4, and finally exits from the laser entrance on the upper surface of the magneto-optical crystal 4. During transmission inside the magneto-optical crystal 4, the polarization direction is rotated counterclockwise by 45 degrees under the combined action of the first magnet array 8 and the second magnet array 9. Then it is incident on the rotating plate 3, and the polarization direction is rotated clockwise by the rotating plate 3, changing back to s-polarized light. Finally, it is incident on the first beam splitter 2, reflected by the first beam splitter 2, and transmitted through its side, thus preventing it from returning to the input fiber collimator, thereby realizing the function of the isolator.

[0029] The beneficial effects of this invention are as follows: By using a disc-shaped magneto-optical crystal with upper and lower surface areas much larger than its side surface area, and attaching heat-conducting sheets of non-diamagnetic material with high thermal conductivity and refractive index lower than that of the magneto-optical crystal to the upper and lower surfaces of the magneto-optical crystal, the heat generated by the magneto-optical crystal after absorbing laser light can be quickly conducted away by the first and second heat-conducting sheets. This significantly reduces the thermal lensing effect and thermally induced birefringence effect of the magneto-optical crystal, improves the laser beam quality, and makes it suitable for use in kilowatt-level or higher high-power laser processing equipment.

[0030] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A disk-type high-power optical isolator, characterized in that: The system includes, in sequence, an input fiber collimator (1), a first optical beam splitter (2), a rotating plate (3), a magneto-optical crystal (4), and a second optical beam splitter (5). The outer surface of the magneto-optical crystal (4) is fitted with a first heat-conducting plate (6) and a second heat-conducting plate (7) for heat conduction. A first magnet array (8) is located on the side of the first heat-conducting plate (6) that is relatively far from the magneto-optical crystal (4), and a second magnet array (9) is located on the side of the second heat-conducting plate (7) that is relatively far from the magneto-optical crystal (4). The input fiber collimator (1) is used to input laser light; the first optical beam splitter (2)... The second beam splitter (5) is used to split a beam of light into p-polarized light and s-polarized light, or to combine p-polarized light and s-polarized light into a beam of light; the rotating plate (3) is used to perform a 45-degree reciprocal polarization rotation on the input laser; the first magnet array (8) and the second magnet array (9) are used to provide a magnetic field for the magneto-optical crystal (4); the magneto-optical crystal (4) has a disk-type structure and is used to perform a 45-degree non-reciprocal polarization rotation on the input laser. The surface area of ​​the magneto-optical crystal (4) in contact with the heat-conducting plate is much larger than the area of ​​its side surface. The laser reflects back and forth between the two surfaces, and the number of reflections is more than two.

2. The disk-type high-power optical isolator according to claim 1, characterized in that: The first heat-conducting sheet (6) is attached to the upper surface of the magneto-optical crystal (4) and covers all surfaces except the laser inlet and laser outlet of the upper surface of the magneto-optical crystal (4). The second heat-conducting sheet (7) is attached to the lower surface of the magneto-optical crystal (4) and its area is greater than or equal to that of the lower surface of the magneto-optical crystal (4).

3. The disk-type high-power optical isolator according to claim 1, characterized in that: The first heat-conducting sheet (6) is attached to the lower surface of the magneto-optical crystal (4) and covers all surfaces except the laser inlet and laser outlet of the lower surface of the magneto-optical crystal (4). The second heat-conducting sheet (7) is attached to the upper surface of the magneto-optical crystal (4) and its area is greater than or equal to that of the upper surface of the magneto-optical crystal (4).

4. The disk-type high-power optical isolator according to claim 2 or 3, characterized in that: The first and second thermal conductive sheets are bonded together with the magneto-optical crystal by adhesive bonding.

5. The disk-type high-power optical isolator according to claim 1, 2 or 3, characterized in that: The rotating plate (3) is a half-wave plate, and the magneto-optical crystal (4) is made of TGG, TSAG or bismuth iron garnet.

6. The disk-type high-power optical isolator according to claim 1, 2 or 3, characterized in that: The first and second heat-conducting sheets are non-diamagnetic materials with high thermal conductivity and a refractive index lower than that of the magneto-optical crystal.

7. The disk-type high-power optical isolator according to claim 6, characterized in that: The first heat-conducting sheet (6) and the second heat-conducting sheet (7) are made of iron-doped aluminum nitride, YAG, sapphire or ruby.

8. The disk-type high-power optical isolator according to claim 2, characterized in that: The optical axes of the input fiber collimator (1), the first optical beam splitter (2) and the rotating plate (3) are inclined to the upper surface of the magneto-optical crystal (4); the inclination angle is 20-70 degrees.

9. The disk-type high-power optical isolator according to claim 1, characterized in that: The combination of the rotating plate (3) and the magneto-optical crystal (4) is used to perform a 90-degree polarization rotation on the input light, while not performing a polarization rotation on the light transmitted in the opposite direction.

Images