An optical component and an optical module for isolating retroreflection

Abstract

The present invention provides an optical component and an optical module for isolating retroreflection light. By sequentially assembling a birefringent crystal, a quartz rotator, a rhombic prism, a wedge lens group, and a wave plate in the laser emission direction, it is ensured that the reflected light emitted from the processing material is separated into two linearly polarized lights after passing through the rhombic prism and the wedge lens group, and the distance between the two linearly polarized lights increases after passing through the birefringent crystal, so as to be away from the forward optical path, and the isolation of retroreflection light is achieved without assembling a magneto-optical crystal and a magnet assembly.

Description

Technical Field

[0001] The present invention relates to the field of laser manufacturing, and particularly to an optical component and an optical module for isolating retro-reflected light. Background Art

[0002] In the field of laser manufacturing, when the processing object of the laser is a highly reflective material such as aluminum or copper, the power of the generated reflected light will also increase accordingly. The high-power reflected light reflected back to the laser will damage the laser processing head. Therefore, a fiber optic isolator is usually set to isolate the retro-reflected light to prevent damage to the laser processing head and the optical fiber. The commonly used fiber optic isolator in the prior art is composed of a Faraday magneto-optical crystal and a half-wave plate, mainly using the non-reciprocity of the Faraday magneto-optical crystal to achieve low-loss transmission of forward-transmitted light and isolation of retro-reflected light. However, this isolator requires the use of a magneto-optical crystal and a magnet assembly, and also requires artificial creation of a magnetic field, resulting in difficult assembly of the device, high cost, and large volume.

[0003] In view of this, overcoming the defects of the prior art is an urgent problem to be solved in the technical field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to isolate retro-reflected light without using a magneto-optical crystal and a magnet assembly.

[0005] The present invention adopts the following technical solutions:

[0006] In a first aspect, an optical component for isolating retro-reflected light includes a quartz lens 1, a pigtail 2, a birefringent crystal 3, a quartz rotator 4, a rhombic prism 5, a wedge lens group 6, and a wave plate 7, wherein:

[0007] The pigtail 2 is fused with the quartz lens 1;

[0008] The birefringent crystal 3, the quartz rotator 4, the rhombic prism 5, the wedge lens group 6, and the wave plate 7 are arranged in sequence along the forward optical path; and the quartz rotator 4 is arranged close to one end of the birefringent crystal 3;

[0009] The quartz lens 1 is used to receive a laser signal and send the laser signal to the birefringent crystal 3;

[0010] In the forward optical path, the birefringent crystal 3 is used to split the laser signal into two lasers with different polarization states; the quartz rotator 4 is used to convert the polarization state of one of the lasers so that the polarization states of the two lasers incident on the rhombic prism 5 are the same; the rhombic prism 5 is used to offset the two lasers so that the light spots of the two lasers are tangent; the wedge lens group 6 is used to shape the light spots of the two lasers to form a combined light spot with a corresponding shape; the wave plate 7 is used to convert the combined light spot into left-handed or right-handed circularly polarized light and then incident on the processing material;

[0011] In the reverse optical path, the left-handed or right-handed circularly polarized light is reflected by the processing material and converted into right-handed or left-handed circularly polarized light, and is received by the wave plate 7, so that the polarization states of the reflected light incident on the wedge lens group 6, the rhombic prism 5, the quartz rotator 4, and the birefringent crystal 3 in sequence are different from the polarization states of the laser transmitted in the forward optical path;

[0012] Among them, after the two reflected lights exit from the rhombic prism 5, one reflected light passes through the quartz rotator 4, and the other reflected light is directly incident on the birefringent crystal 3. The birefringent crystal 3 is used to increase the distance between the two reflected lights so that the reflected light avoids the quartz lens 1.

[0013] Preferably, in the forward optical path, the birefringent crystal 3 is used to split the output laser into a first extraordinary ray 81 and a first ordinary ray 82. The first ordinary ray 82 directly enters the rhombic prism 5, and the first extraordinary ray 81 is converted into a second ordinary ray 83 after passing through the quartz rotator 4 and then enters the rhombic prism 5;

[0014] The rhombic prism 5 is used to offset the first ordinary ray 82 and the second ordinary ray 83 to form a first combined light spot 91;

[0015] The wedge lens group 6 is used to shrink the first combined light spot 91 into a second combined light spot 92. The second combined light spot 92 is converted into circularly polarized light after passing through the wave plate 7 and then incident on the processing material.

[0016] Preferably, in the reverse optical path, the reflected light exits from the processing material;

[0017] The wave plate 7 is used to convert the reflected light into a second extraordinary ray 84;

[0018] The wedge lens group 6 and the rhombic prism 5 are used to separate the second extraordinary ray 84 into a third extraordinary ray 85 and a fourth extraordinary ray 86;

[0019] The fourth e-ray 86 directly enters the birefringent crystal 3. The third e-ray 85 is converted into the third o-ray 87 after passing through the quartz rotator 4 and then enters the birefringent crystal 3. The distance between the fourth e-ray 86 and the third o-ray 87 increases in the middle of the birefringent crystal 3.

[0020] Preferably, the rhombic prism 5 includes: a first transmission surface 51 and a second transmission surface 52, where:

[0021] The first transmission surface 51 and the second transmission surface 52 are respectively located on both sides of the rhombic prism 5. In the forward optical path, the first transmission surface 51 is used to receive incident light, and the second transmission surface 52 is used to emit light;

[0022] Both the first transmission surface 51 and the second transmission surface 52 are coated with an antireflection film.

[0023] Preferably, the rhombic prism 5 further includes: a first reflection surface 53 and a second reflection surface 54, where:

[0024] The first reflection surface 53 is located at the upper end of the rhombic prism 5, and the second reflection surface 54 is located at the lower end of the rhombic prism 5;

[0025] Both the first reflection surface 53 and the second reflection surface 54 are coated with a reflection film.

[0026] Preferably, the wedge lens group 6 includes two right-angled prisms 61, where:

[0027] The two right-angled prisms 61 are arranged in sequence along the forward optical path;

[0028] The right-angled surface 611 of the right-angled prism 61 is used to receive the light beam, and the right-angled surface 611 of the right-angled prism 61 is perpendicular to the incident direction of the light beam. The inclined surface 612 of the right-angled prism 61 is used for the light beam to exit, and it is ensured that the outgoing light of the wedge lens group 6 is parallel to the incident light received by the wedge lens group 6.

[0029] Preferably, the wedge lens group 6 is used to compress the light spot, and the compression ratio is

[0030] where M is the compression ratio, n is the refractive index of the right-angled prism 61, and θ is the apex angle of the right-angled prism 61.

[0031] Preferably, the wave plate 7 is a quarter-wave plate, and the optical axis of the wave plate 7 forms a 45-degree angle with the polarization direction of the incident light.

[0032] Preferably, the quartz lens 1 includes: a quartz rod 11 and a quartz tube 12, where:

[0033] The quartz rod 11 is inserted inside the quartz tube 12. The bottom end of the quartz rod 11 and the bottom end of the quartz tube 12 are on the same end face. The bottom end of the quartz rod 11 is used for fusion splicing with the tail fiber 2. The top end of the quartz tube 12 is an arc-shaped cap 121 that wraps the top end of the quartz rod 11 in an arc shape.

[0034] The bottom end of the quartz rod 11 receives the laser from the tail fiber 2. The quartz rod 11 is used to reduce the power density of the passing laser. After passing through the quartz rod 11, the laser exits from the arc-shaped cap 121 at the top end of the quartz tube 12. The arc-shaped cap 121 at the top end of the quartz tube 12 is used for collimating the laser.

[0035] In a second aspect, an optical module includes the optical component for isolating retroreflection light described above.

[0036] The present invention provides an optical component and an optical module for isolating retroreflection light. By sequentially assembling a birefringent crystal, a quartz rotator, a rhombic prism, a wedge lens group, and a wave plate in the laser output direction, it is ensured that the reflected light of the laser exiting from the processing material is separated into two linearly polarized lights after passing through the rhombic prism and the wedge lens group, and the distance between the two linearly polarized lights increases after passing through the birefringent crystal, thus moving away from the forward optical path. Without assembling a magneto-optical crystal and a magnet component, the isolation of retroreflection light is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 FIG. 18 is a schematic structural diagram of an optical component for isolating retroreflection light provided by an embodiment of the present invention;

[0039] Figure 2 FIG. 22 is a schematic transmission diagram of the forward optical path of an optical component for isolating retroreflection light provided by an embodiment of the present invention;

[0040] Figure 3 FIG. 26 is a schematic transmission diagram of the reverse optical path of an optical component for isolating retroreflection light provided by an embodiment of the present invention;

[0041] Figure 4 FIG. 30 is a schematic structural diagram of a rhombic prism provided by an embodiment of the present invention;

[0042] Figure 5 FIG. 34 is a schematic structural diagram of a wedge lens group provided by an embodiment of the present invention;

[0043] Figure 6It is a schematic structural diagram of a quartz lens for an optical component that isolates retroreflection provided by an embodiment of the present invention;

[0044] Figure 7 It is a schematic structural diagram of an intermediate step of manufacturing a quartz lens for an optical component that isolates retroreflection provided by an embodiment of the present invention;

[0045] Among them, the reference numerals in the drawings are as follows:

[0046] Quartz lens 1; quartz rod 11; quartz tube 12; arc cap 121; pigtail 2; birefringent crystal 3; quartz rotator 4; rhombic prism 5; first transmission surface 51; second transmission surface 52; first reflection surface 53; second reflection surface 54; wedge lens group 6; right-angle prism 61; right-angle surface 611; inclined surface 612; wave plate 7; first extraordinary ray 81; first ordinary ray 82; second ordinary ray 83; second extraordinary ray 84; third extraordinary ray 85; fourth extraordinary ray 86; third ordinary ray 87; first combined light spot 91; second combined light spot 92. Detailed implementation manners

[0047] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] In the description of the present invention, the orientation or positional relationships indicated by the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0049] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Embodiment 1:

[0051] Embodiment 1 of the present invention provides an optical component for isolating retroreflection, as Figure 1 shown, including a quartz lens 1, a pigtail 2, a birefringent crystal 3, a quartz rotator 4, a rhombic prism 5, a wedge lens group 6 and a wave plate 7.

[0052] The optical component for isolating retroreflection in this embodiment is mainly applied to the scenario of processing high-reflectivity materials by high-power laser devices.

[0053] The pigtail 2 is fused with the quartz lens 1.

[0054] Since the laser emission end of the pigtail fiber 2 may be damaged if it is contaminated with dust or other impurities, when the pigtail fiber 2 is connected to the bottom end of the quartz lens 1, the connection needs to be sealed, and the pigtail fiber 2 is selected to be fused with the quartz lens 1.

[0055] As Figure 1 shown, the birefringent crystal 3, the quartz rotator 4, the rhombic prism 5, the wedge lens group 6 and the wave plate 7 are arranged in sequence along the forward optical path; and the quartz rotator 4 is arranged close to one side end of the birefringent crystal 3.

[0056] The quartz lens 1 is used to receive the laser signal and send the laser signal to the birefringent crystal 3.

[0057] Wherein the quartz lens 1 is used to reduce the power density of the laser and collimate the laser.

[0058] As Figure 2 shown, in the forward optical path, the birefringent crystal 3 is used to split the laser signal into two lasers with different polarization states; the quartz rotator 4 is used to convert the polarization state of one of the lasers so that the polarization states of the two lasers incident on the rhombic prism 5 are the same; the rhombic prism 5 is used to offset the two lasers so that the light spots of the two lasers are tangent; the wedge lens group 6 is used to shape the light spots of the two lasers to form a combined light spot with a corresponding shape; the wave plate 7 is used to convert the combined light spot into left-handed or right-handed circularly polarized light and then incident on the processing material.

[0059] The first combined light spot 91 is that the light spots of the two lasers are tangent to ensure that there is no gap between the two lasers and prevent the gap between the light beams from affecting the subsequent processing of the material.

[0060] In this embodiment, the forward optical path represents the optical path and direction of the laser from the emission of the pigtail fiber 2 until it reaches the processing material. After the laser reaches the processing material, the generated reflected light is transmitted along the reverse optical path.

[0061] The processing material is the object of laser processing during the laser manufacturing process. In this embodiment, when the processing object is a high-reflectivity material such as aluminum or copper, the power of the generated reflected light will also increase, and it is easier to damage the end face of the pigtail fiber 2 or damage the laser processing head by the back-reflected light. The quartz lens 1 avoids the above situation by reducing the power density of the emitted laser.

[0062] As Figure 3As shown, in the reverse optical path, the left-handed or right-handed circularly polarized light is reflected by the processing material and converted into right-handed or left-handed circularly polarized light, and is received by the wave plate 7, so that the polarization states of the reflected light incident on the wedge lens group 6, the rhombic prism 5, the quartz rotator 4, and the birefringent crystal 3 in sequence are different from the polarization state of the laser transmitted in the forward optical path.

[0063] Among them, after the two paths of reflected light exit from the rhombic prism 5, one path of reflected light passes through the quartz rotator 4, and the other path of reflected light is directly incident on the birefringent crystal 3. The birefringent crystal 3 is used to increase the distance between the two paths of reflected light, so that the reflected light avoids the quartz lens 1. In the reverse optical path, the quartz rotator 4 is used to convert circularly polarized light into linearly polarized light perpendicular to the vibration direction of the incident polarized light. Then, after the two paths of reflected light pass through the birefringent crystal 3, the refraction directions are also different, increasing the distance between the two paths of reflected light, so that the reflected light avoids the quartz lens 1.

[0064] In this embodiment, the reverse optical path represents the optical path and direction of the reflected light from the processing material until it exits from the birefringent crystal 3. Among them, except for the optical path after the reflected light is incident on the birefringent crystal 3, the remaining optical path is the same as the path of the forward optical path.

[0065] In the field of laser manufacturing, when the processing object of the laser is a highly reflective material such as aluminum or copper, the power of the generated reflected light will also increase accordingly. The high-power reflected light reflected back to the laser will damage the laser processing head. Therefore, usually, on the one hand, by setting a quartz end cap to reduce the power density of the output laser, thereby reducing the density of the reflected light. However, considering that a collimator is also required to collimate the output laser, it usually occupies a large space and has a low integration degree. On the other hand, by setting a fiber optic isolator to isolate the reflected light to prevent damage to the laser processing head and the optical fiber. The commonly used fiber optic isolator in the prior art is composed of a Faraday magneto-optical crystal and a half-wave plate 7, mainly using the non-reciprocity of the Faraday magneto-optical crystal to achieve low-loss transmission of the forward-transmitted light and isolation of the reflected light. However, this isolator requires the use of a magneto-optical crystal and a magnet, and also requires artificial creation of a magnetic field, resulting in difficult assembly of the device, high cost, and large volume.

[0066] The optical component for isolating retroreflection provided in this embodiment reduces the power density of the laser and collimates the laser by arranging a quartz lens 1 at the laser emission position of the pigtail fiber 2. By sequentially assembling a birefringent crystal 3, a quartz rotator 4, a rhombic prism 5, a wedge lens group 6, and a wave plate 7 in the laser emission direction, it is ensured that the reflected light emitted from the processing material is separated into two linearly polarized lights after passing through the rhombic prism 5 and the wedge lens group 6, and the distance between the two linearly polarized lights increases after passing through the birefringent crystal 3, so as to move away from the forward optical path, and the isolation of retroreflection is achieved without assembling a magneto-optical crystal and a magnet assembly.

[0067] In the forward optical path, the birefringent crystal 3 is used to divide the emitted laser into a first extraordinary ray 81 and a first ordinary ray 82. The first ordinary ray 82 directly enters the rhombic prism 5, and the first extraordinary ray 81 enters the rhombic prism 5 after being converted into a second ordinary ray 83 through the quartz rotator 4.

[0068] The rhombic prism 5 is used to offset the first ordinary ray 82 and the second ordinary ray 83 to form a first combined light spot 91.

[0069] The wedge lens group 6 is used to condense the first combined light spot 91 into a second combined light spot 92, and the second combined light spot 92 is converted into left-handed or right-handed circularly polarized light after passing through the wave plate 7 and then incident on the processing material.

[0070] In the forward optical path, the birefringent crystal 3 divides the emitted laser into a first extraordinary ray 81 and a first ordinary ray 82, which specifically includes:

[0071] The optical axis of the birefringent crystal 3 and the laser incident surface of the birefringent crystal 3 are in the same plane, so as to ensure that the polarization directions of the first extraordinary ray 81 and the first ordinary ray 82 are perpendicular to each other.

[0072] The birefringent crystal 3 divides the laser emitted from the quartz lens 1 into two linearly polarized lights, namely the first extraordinary ray 81 and the first ordinary ray 82, whose polarization states are perpendicular to each other and are separated in the vertical propagation direction.

[0073] Since the polarization directions of the first extraordinary ray 81 and the first ordinary ray 82 are perpendicular to each other, in order to ensure that the two linearly polarized lights can be tangent to the light spot and form combined light subsequently, it is necessary to adjust the polarization directions of the two linearly polarized lights to be consistent. Therefore, this embodiment also involves the following design:

[0074] The first extraordinary ray 81 enters the rhombic prism 5 after being converted into a second ordinary ray 83 through the quartz rotator 4, which specifically includes:

[0075] The quartz rotator 4 rotates the polarization direction of the incident first e-light 81 by 90 degrees, thereby converting the first e-light 81 into the second o-light 83 , and the vibration direction of the second o-light 83 is consistent with the vibration direction of the first o-light 82 .

[0076] In the forward optical path, only the first e-light 81 will be converted into the second o-light 83 through the quartz optical rotator 4, and the first o-light 82 will directly enter the rhombus prism 5 without passing through the quartz optical rotator 4, so that the vibration directions of the two beams of linear polarization are the same, and then the second o-light 83 is positionally shifted through the subsequent rhombus prism 5, so that the first o-light 82 and the second o-light 83 can be synthesized into a combined light spot.

[0077] In the reverse optical path, the reflected light is emitted from the processed material; the reflected light, i.e., circularly polarized light, is converted into the second e-light 84 after passing through the wave plate 7; the second e-light 84 is separated into the third e-light 85 and the fourth e-light 86 after passing through the wedge lens group 6 and the rhombus prism 5; the fourth e-light 86 directly enters the birefringent crystal 3, and the third e-light 85 is converted into the third o-light 87 after passing through the quartz rotator 4 and enters the birefringent crystal 3, and the distance between the fourth e-light 86 and the third o-light 87 in the birefringent crystal 3 becomes larger, thereby staggering the path of the forward optical path to achieve isolation of the reflected light.

[0078] When the target object emits reflected light, the polarization state of the reflected light is reversed to generate left-handed or right-handed polarized light, which is converted into the second e-light 84 after passing through the wave plate 7 .

[0079] Among them, the first e-light 81, the second e-light 84, the third e-light 85, the fourth e-light 86, the first o-light 82, the second o-light 83 and the third o-light 87 are all linearly polarized light.

[0080] like Figure 4 As shown, the rhombus prism 5 includes: a first transmission surface 51, a second transmission surface 52, a first reflection surface 53 and a second reflection surface 54, wherein:

[0081] The first transmission surface 51 and the second transmission surface 52 are respectively located on both sides of the rhombus prism 5. In the forward light path, the first transmission surface 51 is used to receive incident light, and the second transmission surface 52 is used to emit light. The first transmission surface 51 and the second transmission surface 52 are both coated with an anti-reflection film of a first preset wavelength.

[0082] The first reflecting surface 53 is located at the upper end of the rhombus prism 5 , and the second reflecting surface 54 is located at the lower end of the rhombus prism 5 . Both the first reflecting surface 53 and the second reflecting surface 54 are coated with a reflecting film of a second preset wavelength.

[0083] Wherein, the first transmission surface 51 and the second transmission surface 52 are parallel to each other, the first reflection surface 53 and the second reflection surface 54 are parallel to each other. The first reflection surface 53 and the second reflection surface 54 are used to reflect the laser so as to change the position of the laser. Therefore, a reflection film with a first preset wavelength is plated, and the first preset wavelength is set by those skilled in the art according to actual needs; while the first transmission surface 51 and the second transmission surface 52 should have as little impact on the laser as possible. Therefore, an antireflection film with a second preset wavelength is plated, and the second preset wavelength is set by those skilled in the art according to actual needs.

[0084] The first ordinary ray 82 and the second ordinary ray 83 are offset after passing through the rhombic prism 5 to form a first combined light spot 91 for output. Specifically, it includes:

[0085] The second ordinary ray 83 is incident from the first transmission surface 51 of the rhombic prism 5, and then passes through the reflections of the first reflection surface 53 and the second reflection surface 54 in sequence, and exits from the second transmission surface 52. The first ordinary ray 82 is incident from the first transmission surface 51 and directly exits from the second transmission surface 52.

[0086] Since only the position of the second ordinary ray 83 needs to be offset, and the position and direction of the first ordinary ray 82 remain unchanged. Therefore, after the second ordinary ray 83 enters from the first transmission surface 51, it passes through the reflections of the first reflection surface 53 and the second reflection surface 54 twice. Since the first reflection surface 53 and the second reflection surface 54 are parallel to each other, the direction of the second ordinary ray 83 remains unchanged and only the position changes. And the first ordinary ray 82 basically does not change because it only passes through the first transmission surface 51 and the second transmission surface 52. When the first ordinary ray 82 and the second ordinary ray 83 exit from the rhombic prism 5, the light spots of the first ordinary ray 82 and the second ordinary ray 83 are tangent to form a first combined light spot 91. Wherein, the contour of the first combined light spot 91 is elliptical, and the ratio of the long and short axes of the ellipse is close to 2.

[0087] Since most conventional laser processing uses a laser beam with a circular light spot, it is necessary to shrink the contour of the first combined light spot 91 into a circle. Therefore, this embodiment also involves the following design:

[0088] As Figure 5 shown, the wedge lens group 6 includes two right-angle prisms 61, wherein: the two right-angle prisms 61 are arranged in sequence along the forward light path. The right-angle surface 611 of the right-angle prism 61 is used to receive the first combined light spot 91, and the right-angle surface 611 of the right-angle prism 61 is perpendicular to the incident direction of the first combined light spot 91. The inclined surface 612 of the right-angle prism 61 is used for exiting.

[0089] Among them, the second right-angle prism 61 is used for secondary beam shrinking of the light spot on one hand. On the other hand, since the outgoing direction of the light beam changes after refraction through the first right-angle prism 61, it is necessary to ensure that the outgoing direction of the light beam is consistent with the incident direction of the first combined light spot 91 through the secondary refraction of the second right-angle prism 61.

[0090] In this embodiment, the wedge lens group 6 is used to compress the first combined light spot 91, and the compression ratio is where M is the compression ratio, n is the refractive index of the right-angle prism 61, and θ is the apex angle of the right-angle prism 61.

[0091] Among them, the right-angle surface 611 of the right-angle prism 61 is the end face where the right-angle side is located, the inclined surface 612 of the right-angle prism 61 is the end face where the non-right-angle side is located, and the apex angle is the included angle between the right-angle surface 611 and the inclined surface 612.

[0092] The assembly of the first right-angle prism 61 should ensure that its right-angle surface is perpendicular to the incident direction of the first combined light spot 91. When the first combined light spot 91 is incident on the first right-angle prism 61 and exits from the inclined surface 612 of the right-angle prism 61, the first combined light spot 91 undergoes refraction, and the distance between the two light spots in the first combined light spot 91 decreases, completing the first beam shrinking; the first combined light spot 91 after one beam shrinking deflects in angle compared with before the beam shrinking. The second right-angle prism 61 is assembled corresponding to the direction of the first combined light spot 91 after beam shrinking to ensure that the first combined light spot 91 after beam shrinking is perpendicularly incident on the second right-angle prism 61 and is parallel to the direction of the first combined light spot 91 before beam shrinking when exiting from the inclined surface 612 of the right-angle prism 61. The first combined light spot 91 after exiting undergoes refraction again, and the distance between the two light spots in the first combined light spot 91 decreases again, completing the second beam shrinking to obtain the second combined light spot 92, and the contour of the second combined light spot 92 is close to a circle.

[0093] The second combined light spot 92 is perpendicularly incident on the surface of the quarter-wave plate 7, and the angle between the light polarization direction and the optical axis of the quarter-wave plate 7 is 45 degrees. The second combined light spot 92 becomes left-handed or right-handed circularly polarized light after passing through the quarter-wave plate 7, and the left-handed or right-handed circularly polarized light is incident on the processing material.

[0094] As Figure 6 shown, the quartz lens 1 includes: a quartz rod 11 and a quartz tube 12, where: the quartz rod 11 is inserted inside the quartz tube 12, the bottom end of the quartz rod 11 and the bottom end of the quartz tube 12 are on the same end face, the bottom end of the quartz rod 11 is used for fusion splicing with the tail fiber 2, and the top end of the quartz tube 12 is an arc-shaped cap 121 that wraps the top end of the quartz rod 11 in an arc;

[0095] The bottom end of the quartz rod 11 receives the laser from the pigtail 2. The quartz rod 11 is used to reduce the power density of the passing laser. After passing through the quartz rod 11, the laser exits from the arc-shaped cap 121 at the top end of the quartz tube 12. The arc-shaped cap 121 at the top end of the quartz tube 12 is used to collimate the laser.

[0096] Among them, the quartz tube 12 is a fluorine-doped quartz tube 12. The refractive index of the quartz rod 11 is equal to the refractive index of the core of the pigtail 2. The inner diameter of the quartz tube 12 is greater than or equal to the diameter of the quartz rod 11. The length of the quartz tube 12 is greater than the length of the quartz rod 11.

[0097] The manufacturing method of the quartz lens 1 is as follows:

[0098] As Figure 7 shown, insert the quartz rod 11 into the quartz tube 12 to ensure that the bottom end of the quartz rod 11 and the bottom end of the quartz tube 12 are on the same end face. Among them, the length of the quartz tube 12 is greater than the length of the quartz rod 11. Heat the part of the top end of the quartz tube 12 that exceeds the quartz rod 11 at a high temperature. Under the action of surface tension, the top end of the quartz tube 12 forms an arc-shaped cap 121 to wrap the internal quartz rod 11, and the arc-shaped cap 121 is shaped into a preset shape through high-temperature heating. As Figure 6 shown, the arc-shaped cap 121 wraps the quartz rod 11 and is used to collimate the outgoing laser.

[0099] The quartz lens 1 is formed by arranging the quartz rod 11 inside the quartz tube 12 and wrapping the laser output end of the quartz rod 11 with the quartz tube 12, so that the front end of the quartz tube 12 is in the shape of an arc-shaped cap 121. On the premise that the quartz rod 11 itself reduces the power density of the outgoing laser, the outgoing laser is collimated, thus replacing the collimating lens, and there is no need to additionally set a collimator or lens to collimate the laser, improving the integration level.

[0100] Embodiment 2:

[0101] Embodiment 2 of the present invention demonstrates the usage process and method of an optical component for isolating retroreflected light in Embodiment 1 in an actual scenario.

[0102] In this embodiment, the working wavelength of the laser is 1064 nm, the core of the pigtail 2 is 50 μm, the diameter of the quartz rod 11 is 2 mm, the length is 4 mm, the inner diameter of the fluorine-doped quartz tube 12 is 2 mm, the outer diameter is 3 mm, and the length is 6 mm.

[0103] Insert the quartz rod 11 into the quartz tube 12, and heat the part of the quartz tube 12 that extends beyond the quartz rod 11 at a high temperature. Under the action of surface tension, the quartz tube 12 wraps the quartz rod 11 to form a quartz lens 1. Then, fuse the quartz lens 1 with the output pigtail 2 to collimate the laser beam output from the pigtail 2 while reducing the power density of the output laser.

[0104] Assemble a birefringent crystal 3 in the laser output direction. The optical axis of the birefringent crystal 3 coincides with its laser incident surface. The length of the birefringent crystal 3 is 15 mm. After the light beam passes through the birefringent crystal 3, it is divided into an e-ray and an o-ray with mutually perpendicular vibration directions. The separation distance between the e-ray and the o-ray is 1.5 mm. Assemble a quartz rotator 4 in the e-ray transmission direction. The length of the quartz rotator 4 is 7.1 mm. After the e-ray passes through the quartz rotator 4, it is converted into an o-ray. The two o-rays are incident on a rhombic prism 5 to form a first combined spot 91 with an approximately elliptical contour where the two spots are tangent. The major axis of the first combined spot 91 is twice the minor axis diameter. The first combined spot 91 is incident on the right-angle surface 611 of a double-wedge prism group. The refractive index of the double-wedge prism is 1.73, and the apex angle is 31.5 degrees. After passing through the double-wedge prism group, the major axis of the elliptical spot is compressed to 1 / 2, generating a second combined spot 92 with an approximately circular contour. The second combined spot 92 is perpendicularly incident on a quarter-wave plate 7. The optical axis of the quarter-wave plate 7 forms a 45-degree angle with the polarization direction of the second combined spot 92. The second combined spot 92 is converted into a left-handed or right-handed circularly polarized light after passing through the quarter-wave plate 7 and is incident on the workpiece. The polarization state of the reflected light on the workpiece is reversed to generate a right-handed or left-handed circularly polarized light, which is converted into an e-ray after passing through the quarter-wave plate 7. Then, after passing through the double-wedge lens and the rhombic prism 5, the two e-ray spots are separated. One e-ray passes through the quartz rotator 4 and becomes an o-ray. After passing through the birefringent crystal 3, the distance between the two perpendicularly polarized linear light rays with different polarization states is further separated, realizing the isolation of the retroreflected light.

[0105] Embodiment 3:

[0106] Embodiment 3 of the present invention provides an optical module. The optical module includes the optical component for isolating retroreflected light in Embodiment 1. In actual use, other associated components can be configured according to the specific application scenario of the optical module. For the specific structure of the optical component for isolating retroreflected light, please refer to the previous description and will not be elaborated here.

[0107] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical component for isolating retroreflection, characterized in that, The invention comprises a quartz lens (1), a pigtail (2), a birefringent crystal (3), a quartz optical rotator (4), a rhombus prism (5), a wedge lens group (6) and a wave plate (7), wherein: The pigtail (2) is fused to the quartz lens (1); The birefringent crystal (3), the quartz optical rotator (4), the rhombus prism (5), the wedge lens group (6) and the wave plate (7) are arranged in sequence along the forward optical path; and the quartz optical rotator (4) is arranged close to one side end of the birefringent crystal (3); The quartz lens (1) is used to receive a laser signal and send the laser signal to the birefringent crystal (3); In the forward optical path, the birefringent crystal (3) is used to split the laser signal into two laser beams with different polarization states; the quartz rotator (4) is used to convert the polarization state of one of the laser beams so that the polarization states of the two laser beams incident on the rhombus prism (5) are the same; the rhombus prism (5) is used to offset the two laser beams so that the light spots of the two laser beams are tangent to each other; the wedge lens group (6) is used to shape the light spots of the two laser beams to form a combined light spot of a corresponding shape; the wave plate (7) is used to convert the combined light spot into left-handed or right-handed circularly polarized light and then incident on the processing material; In the reverse optical path, the left-handed or right-handed circularly polarized light is converted into right-handed or left-handed circularly polarized light after being reflected by the processed material and received by the wave plate (7), so that the polarization state of the reflected light sequentially incident on the wedge-shaped lens group (6), the rhombus prism (5), the quartz optical rotator (4) and the birefringent crystal (3) is different from the polarization state of the laser light transmitted in the forward optical path; After the two reflected lights are emitted from the rhombus prism (5), one reflected light passes through the quartz optical rotator (4), and the other reflected light is directly incident on the birefringent crystal (3). The birefringent crystal (3) is used to increase the distance between the two reflected lights so that the reflected lights avoid the quartz lens (1).

2. The optical component for isolating retroreflection according to claim 1, characterized in that, In the forward optical path, the birefringent crystal (3) is used to split the outgoing laser light into a first e-light (81) and a first o-light (82), wherein the first o-light (82) directly enters the rhombic prism (5), and the first e-light (81) is converted into a second o-light (83) by the quartz optical rotator (4) and then enters the rhombic prism (5); The rhombus prism (5) is used to offset the first o-light (82) and the second o-light (83) to form a first combined light spot (91); The wedge lens group (6) is used to shrink the first combined light spot (91) into a second combined light spot (92); the second combined light spot (92) is converted into circularly polarized light after passing through the wave plate (7) and is incident on the processing material.

3. The optical component for isolating retroreflection according to claim 2, characterized in that, In the reverse light path, the reflected light emerges from the processed material; The wave plate (7) is used to convert the reflected light into second e-light (84); The wedge lens group (6) and the rhombus prism (5) are used to separate the second e-light (84) into a third e-light (85) and a fourth e-light (86); The fourth e-ray (86) directly enters the birefringent crystal (3). The third e-ray (85) is converted into a third o-ray (87) by the quartz rotator (4) and then enters the birefringent crystal (3). The distance between the fourth e-ray (86) and the third o-ray (87) increases in the middle of the birefringent crystal (3).

4. The optical component for isolating retroreflection according to claim 1, wherein, The rhombic prism (5) includes: a first transmission surface (51) and a second transmission surface (52), where: The first transmission surface (51) and the second transmission surface (52) are respectively located on both sides of the rhombic prism (5). In the forward optical path, the first transmission surface (51) is used to receive incident light, and the second transmission surface (52) is used to emit light; Both the first transmission surface (51) and the second transmission surface (52) are coated with antireflection films.

5. The optical component for isolating retroreflection according to claim 4, wherein, The rhombic prism (5) further includes: a first reflection surface (53) and a second reflection surface (54), where: The first reflection surface (53) is located at the upper end of the rhombic prism (5), and the second reflection surface (54) is located at the lower end of the rhombic prism (5); Both the first reflection surface (53) and the second reflection surface (54) are coated with reflection films.

6. The optical component for isolating retroreflection according to claim 1, wherein The wedge lens group (6) includes two right-angle prisms (61), where: The two right-angle prisms (61) are arranged in sequence along the forward optical path; The right-angle surface (611) of the right-angle prism (61) is used to receive the light beam, and the right-angle surface (611) of the right-angle prism (61) is perpendicular to the incident direction of the light beam. The inclined surface (612) of the right-angle prism (61) is used for the light beam to exit, and it is ensured that the outgoing light of the wedge lens group (6) is parallel to the incident light direction received by the wedge lens group (6).

7. The optical component for isolating retroreflection according to claim 6, characterized in that, The wedge lens group (6) is used to compress the light spot, and the compression ratio is Wherein, M is the compression ratio, n is the refractive index of the right-angle prism (61), and θ is the apex angle of the right-angle prism (61).

8. The optical component for isolating retroreflection according to claim 1, wherein, The wave plate (7) is a quarter-wave plate, and the optical axis of the wave plate (7) forms a 45-degree angle with the polarization direction of the incident light.

9. The optical component for isolating retroreflection according to any one of claims 1 to 8, characterized in that, The quartz lens (1) includes: a quartz rod (11) and a quartz tube (12), where: The quartz rod (11) is inserted inside the quartz tube (12). The bottom end of the quartz rod (11) is on the same end face as the bottom end of the quartz tube (12). The bottom end of the quartz rod (11) is used for fusion splicing with the pigtail fiber (2). The top end of the quartz tube (12) is an arc-shaped cap (121) that arc-wraps the top end of the quartz rod (11); The bottom end of the quartz rod (11) receives the laser from the pigtail fiber (2). The quartz rod (11) is used to reduce the power density of the passing laser. The laser passes through the quartz rod (11) and then exits from the arc-shaped cap (121) at the top end of the quartz tube (12). The arc-shaped cap (121) at the top end of the quartz tube (12) is used to collimate the laser.

10. An optical module, characterized in that, It includes an optical component for isolating retro-reflected light as described in any one of claims 1 to 9.

Images