Reflection-light-resistant optical device and laser

Abstract

The invention belongs to the field of lasers, and discloses an anti-light-returning optical device and a laser wherein the anti-light-returning optical device comprises an optical fiber light path, the optical fiber light path comprises at least two first light path sections, and optical fibers of the first light path sections are homogenized optical fibers; the first light filtering device is arranged on the first light path section, the first light filtering device comprises a heat conductor wrapping the outer side of the optical fiber on the first light path section, and a cladding of the optical fiber on the inner side of the heat conductor is provided with a first light emitting part for emitting cladding light; wherein the diameters of fiber cores of the homogenized optical fibers of the plurality of optical fiber sections I on the optical fiber optical path are sequentially decreased along the direction from the optical output end to the optical input end of the optical fiber optical path. Returning light is filtered step by step, the power of the returning light entering the main light path is accurately monitored, and it is ensured that the laser can continuously machine high-reflectivity materials.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers, and in particular relates to an optical device and a laser capable of resisting back-returning light. Background Art

[0002] When lasers are used to process highly reflective materials such as aluminum and copper, part of the laser light emitted by the laser will be reflected back into the optical fiber path of the laser. This part of light is called return light. In the prior art, the beam combiner set in the optical fiber path does not have the function of resisting high reflection. Usually, multiple beam combiners are connected in series, and the optical fibers are combined and connected through the beam combiner. The glue and metal shell in the beam combiner are used to conduct heat outward. However, this has a poor anti-high reflection effect, and will make the overall volume larger and easy to burn. Summary of the invention

[0003] In view of this, the object of the present invention is to provide an optical device and a laser for resisting backlight, so as to solve the problem that the optical fiber optical path of the existing laser has poor anti-backlight effect when the laser processes high-reflective materials.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: In one aspect, an optical device for preventing backscattered light is provided, comprising: An optical fiber optical path, wherein the optical fiber optical path comprises at least two optical path sections 1, and the optical fiber of the optical path section 1 is a homogenized optical fiber; A light filtering device 1 is arranged on the optical path section 1, the light filtering device 1 comprises a heat conductor coated on the outer side of the optical fiber on the optical path section 1, and the cladding of the optical fiber inside the heat conductor is provided with a light emitting portion 1 for emitting cladding light; Among them, the core diameter of the homogenizing optical fiber of the multiple optical path sections on the optical fiber optical path decreases in sequence from the optical output end to the optical input end of the optical fiber optical path.

[0005] In a possible implementation, the optical fibers of two adjacent optical path segments one are fusion-spliced, and in the two adjacent optical path segments one, the optical fiber core end face of the optical path segment one with a larger optical fiber core diameter and the optical fiber cladding end face of the optical path segment one with a smaller optical fiber core diameter are alternately arranged in a radial direction to form an incident path between the two for the core light of the high-order mode of the optical path segment one with a larger optical fiber core diameter to be incident on the optical fiber cladding of the optical path segment one with a smaller optical fiber core diameter.

[0006] In a possible implementation, the optical fiber optical path also includes at least one optical path segment 2 located in the light input direction of the optical path segment 1 having the smallest core diameter in the optical path segment 1, the optical path segment 2 is provided with a light filtering device 2 coated on the outside of the optical fiber on the optical path segment 2, the optical fiber cladding on the inner side of the optical filtering device 2 is provided with a light emitting portion 2 for emitting cladding light, and the core diameter of the optical path segment 2 is smaller than the core diameter of the adjacent optical path segment 1.

[0007] In a possible implementation, the optical fiber NA value of the optical path section 2 is smaller than the optical fiber NA value of the optical path section 1 adjacent to the optical path section 2.

[0008] In a possible implementation, a cooling component is further included, and the first optical filtering device and the second optical filtering device are both arranged on the cooling component.

[0009] In a possible implementation, it also includes a beam combiner arranged at the optical input end of the optical fiber optical path, which combines and connects the optical fiber of the optical fiber optical path with a plurality of branch optical fibers, wherein the plurality of branch optical fibers include a laser input optical fiber and a return light output optical fiber.

[0010] In a possible implementation, an optical power detection device 1 is provided in the light output direction of the return light output optical fiber, and a detection component is provided in the return light output direction of each optical path section 1 of the optical fiber optical path, and the detection component includes a temperature detection device and / or an optical power detection device 2.

[0011] In a possible implementation, the heat conductor is made of quartz glass.

[0012] On the other hand, a laser is also provided, comprising an optical device for resisting backscattered light according to any of the above technical solutions.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The optical device and laser for resisting reflected light of the present invention have multiple optical path sections with decreasing core diameters and an optical filter device arranged on each optical path section. The reflected light entering from the optical output end of the optical fiber optical path includes cladding light and core light. When the cladding light passes through the optical filter device on the optical path section, it can be emitted from the light filter device through the light output part to be filtered, and the core light can be changed into multiple core lights of higher-order modes with worse directivity by the homogenization effect of the uniform optical fiber. The core light of the higher-order mode can enter the cladding when passing through the cores of different diameters, and the reflected light entering the cladding can enter the optical filter device through the light output part to be filtered, and the heat generated by the filtered core light in the heat conductor can be exported, so that the step-by-step filtering of the reflected light can be achieved, ensuring the stable light output of the laser.

[0014] Moreover, by providing optical path section 2 and optical filtering device 2 thereon, while being able to further play a certain filtering role through the optical fiber with a smaller core diameter, the optical path section 2 with a smaller optical fiber NA value can also have a smaller receiving angle range, so that the core light larger than the angle range leaks into the cladding without being stripped, further improving the filtering effect of the return light.

[0015] In addition, the power and temperature of the returning light entering the main optical path can be accurately monitored to ensure that the laser can continuously process highly reflective materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a schematic structural diagram of an optical device for preventing back-reflected light; Figure 2 A schematic diagram of the optical fiber connection structure of an optical path section 1 and an optical path section 2 of an optical device for resisting back-reflection light; Figure 3 The present invention is a schematic diagram of the light filtering principle between two optical path sections 1 or between optical path section 1 and optical path section 2 of an optical device for resisting back-reflection light.

[0017] In the figure: 1-first optical path section 1; 2-second optical path section 1; 3-optical path section 2; 4-light output part 1; 5-light output part 2; 6-cold plate; A-beam combiner; A1-branch optical fiber 1; A2-branch optical fiber 2; A3-laser input optical fiber; C1-first optical filter device 1; C2-second optical filter device 1; C3-optical filter device 2; M1-monitoring sensor; M2-detection component 1; M3-detection component 2; M4-detection component 3. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0019] When a laser is used to process highly reflective materials such as aluminum and copper, part of the laser light emitted by the laser will be reflected back into the optical fiber light path of the laser. This part of light is called return light. In the prior art, the combiner arranged on the optical fiber optical path does not have the function of anti-high reflection. Usually, multiple combiners are connected in series, and the optical fibers are combined and connected through the combiner, and the glue and metal shell in the combiner are used to conduct heat to the outside. However, since the reflected light is divided into cladding light and core light after entering the optical fiber optical path, and the cladding light accounts for more than about 90%, if the heat is filtered out through the combiner, the reflected light of the core and cladding will be emitted from the inside of the combiner, and heat will be conducted through the combiner shell. There is packaging glue in the combiner. Due to the structure of the combiner, the reflected light of the cladding will leak into the inside of the combiner in large quantities, and the glue can only withstand and stabilize below 70°C for a long time. If the cladding light is dissipated through the glue for a long time, the temperature will increase to exceed the temperature that can be stably tolerated, which will cause the combiner to burn out, making it unable to be used as a heat dissipation structure, and the anti-high reflection effect is poor. If a series setting is adopted, there is also a problem of burning, and the overall volume is also larger.

[0020] To solve the above technical problems, please refer to Figure 1-Figure 3As shown, an embodiment of the present application provides an optical device for resisting back-reflected light, including: an optical fiber optical path and a light filtering device.

[0021] The optical device can be used for lasers, and can also be used for other optical devices with high transmission light power, without limitation. The optical fiber optical path is used to transmit optical signals, and the optical filter device is used to filter the return light entering the optical fiber optical path.

[0022] Please refer to Figure 1-Figure 3 As shown, in an embodiment of the present application, the optical fiber optical path includes at least two optical path segments one, and the optical fiber of the optical path segment one is a homogenizing optical fiber; an optical filtering device one is arranged on the optical path segment one, and the optical filtering device one includes a heat conductor coated on the outer side of the optical fiber on the optical path segment one, and the cladding of the optical fiber inside the heat conductor is provided with a light emitting portion 4 for emitting cladding light; wherein the core diameters of the homogenizing optical fibers of the multiple optical path segments one on the optical fiber optical path decrease successively along the direction from the optical output end to the optical input end of the optical fiber optical path.

[0023] The optical fiber optical path is divided into a plurality of optical path sections 1, and the optical fiber 1 of each optical path section is a homogenized optical fiber, which can change the core light into a higher-order mode light with worse directivity, and cooperate with the different changes in the core diameter to facilitate the stripping of the return light in the core. The optical filtering device 1 includes a heat conductor, which is made of a heat-conducting material suitable for optical fiber, which is coated on the outside of the light and can filter the return light in the cladding and the core light entering the cladding. Specifically, it emits light through a light-emitting portion 14 set in the cladding of the optical path section 1, that is, the return light propagating in the cladding will be emitted outward through the light-emitting portion 14 and injected into the heat conductor for filtering when passing through the light-emitting portion 14; the light-emitting portion 14 can be formed by destroying the optical fiber cladding of the optical path section 1 to form a gap for the cladding light to be emitted. The core diameter of the homogenized optical fiber decreases successively from the optical output end to the optical input end of the optical fiber path. The core light converted into a high-order mode can be gradually divided into parts and enter the cladding when passing through the optical cores of different diameters, and the return light entering the cladding can enter the optical filter device through the light output part 4 to be filtered out. At the same time, the return light of the cladding part of the optical filter device can be filtered out to filter out most of the return light in the optical fiber path. By filtering step by step and filtering in parts in sequence, the thermal load of the heat conductor will not be increased too much, and the filtering effect of the return light will be significantly improved.

[0024] Through the above technical scheme, multiple optical path sections 1 with decreasing core diameters and an optical filtering device 1 arranged on each optical path section 1, the return light entering from the optical output end of the optical fiber optical path includes cladding light and core light, the cladding light can be emitted into the optical filtering device 1 through the light output part 14 when passing through the optical filtering device 1 on the optical path section 1 for filtering, and the core light can be changed into multiple core lights of higher-order modes with worse directionality by the homogenization effect of the uniform optical fiber, the core light of the higher-order mode can enter the cladding when passing through cores of different diameters, and the return light entering the cladding can enter the optical filtering device 1 through the light output part 14 to be filtered, and the heat generated by the filtered core light in the heat conductor can be exported, so that the step-by-step filtering of the return light can be achieved to ensure the stable light output of the laser.

[0025] In one embodiment, the optical fibers of two adjacent optical path segments one are fusion-spliced, and in the two adjacent optical path segments one, the optical fiber core end face of the optical path segment one with a larger optical fiber core diameter and the optical fiber cladding end face of the optical path segment one with a smaller optical fiber core diameter are alternately arranged in a radial direction to form an incident path between the two for the core light of the higher-order mode of the optical path segment one with a larger optical fiber core diameter to be incident into the optical fiber cladding of the optical path segment one with a smaller optical fiber core diameter.

[0026] The adjacent optical path sections of the optical fiber optical path are connected by fusion splicing, for example, direct fusion splicing is performed by a Fujikura fusion splicer. Correspondingly, there are fusion-jointed end faces between the optical fibers. Since the optical fiber core diameters of each optical path section are different, the optical fiber core end faces of the optical path section with a larger optical fiber core diameter and the optical fiber cladding end faces of the optical path section with a smaller optical fiber core diameter are alternately arranged in the radial direction. In this way, an incident path can be formed between the core end faces of different diameters for the core light of the higher-order mode of the optical path section with a larger optical fiber core diameter to be incident on the optical fiber cladding of the optical path section with a smaller optical fiber core diameter. Through the incident path, the core light of the higher-order mode in the core can be incident on the cladding along the incident path, and then emitted through the light output portion 4, and then filtered out by the incident light filter 1.

[0027] In order to further improve the filtering effect of the returned light, the optical fiber optical path further includes at least one optical path segment 2 3 which is arranged on the light input direction of the optical path segment 1 having the smallest core diameter in the optical path segment 1, and the optical path segment 2 3 is provided with an optical filtering device 2 C3 which is coated on the outer side of the optical fiber on the optical path segment 2 3, and the optical fiber cladding on the inner side of the optical filtering device 2 C3 is provided with a light emitting portion 2 5 for emitting cladding light, and the core diameter of the optical path segment 2 3 is smaller than the core diameter of the adjacent optical path segment 1.

[0028] In this way, by setting the optical path section 2 3 in the light input direction of the optical path section 1, the optical filter device 2 C3 on the optical path section 2 3 has the same structure and principle as the optical filter device 1, and cooperates with the optical fiber core with a smaller core diameter than the minimum diameter core of the optical path section 1 to further filter the return light in the core and enter the cladding for emission, and the optical filter device 2 C3 can filter the return light entering this part. In the specific implementation process, the optical fiber of the optical path section 2 3 can be a homogenized optical fiber, which further changes the return light into the return light of the higher order mode. Of course, it is also possible not to use a homogenized optical fiber, and only use a smaller diameter core in conjunction with the optical filter device 2 C3 to filter the return light, and there is no limitation.

[0029] On this basis, in order to further improve the filtering effect, the fiber NA value of the optical path section 2 3 is smaller than the fiber NA value of the optical path section 1 adjacent to the optical path section 2 3. The size of the fiber NA value determines the size of the divergence angle of laser transmission. As the fiber NA value gradually decreases, the core light will not be able to enter the fiber with a smaller NA value from the fiber with a larger NA value. Due to the difference in the core diameter, the core light that cannot enter will be incident on the cladding for stripping, which can further improve the filtering effect of the return light.

[0030] In order to facilitate the connection between the optical path section 2 3 and components such as the combiner A, its optical fiber is consistent with the optical fiber of these components, which can reduce operations such as optical fiber fusion splicing. Therefore, the optical fiber of the optical fiber path 2 uses the same optical fiber material as these components, that is, no homogenized optical fiber is used. Through the reduction of the optical fiber NA value, the decreasing change of the fiber core diameter and the mutual cooperation of the optical filtering device 2 C3, a better return light filtering effect can be achieved.

[0031] In the specific implementation process, a cooling component is also included, and the optical filter device 1 and the optical filter device 2 C3 are both arranged on the cooling component. The optical path segment 1 and the optical path segment 2 3 of the optical fiber optical path are mainly arranged on a cooling component such as a cold plate 6, and the cooling component can cool down the optical filter device 1 on the optical path segment 1 and the optical filter device 2 C3 on the optical path segment 2 3, so that the filtered return light can be dissipated through heat conduction and cooling.

[0032] In an embodiment of the present application, it may also include a combiner A arranged at the optical input end of the optical fiber optical path, and the combiner A combines and connects the optical fiber of the optical fiber optical path with multiple branch optical fibers, and the multiple branch optical fibers include a laser input optical fiber A3 and a return light output optical fiber.

[0033] The laser input fiber A3 of the combiner A is used for laser input, which is consistent with the fiber of the optical filter device C3 and is not a uniform light fiber. The branch fiber is combined and connected with the laser input fiber A3, and the return light can be output through the branch fiber, that is, the remaining return light after filtering out most of it is divided into multiple parts, of which a very small amount of return light will enter the laser input fiber A3, and the other part of the return light will be emitted through the return light output fiber, thereby avoiding the remaining return light from entering the laser input fiber A3, further reducing the impact of luminescence on the stability of the light source, and also facilitating the judgment of the real-time situation of the return light based on the return light output by the branch fiber, such as whether there is still return light or what is the optical power of the return light, thereby facilitating the adjustment of the laser operation according to the return light situation.

[0034] On this basis, in order to realize the detection of the returned light data, an optical power detection device 1 is provided in the light output direction of the returned light output optical fiber, and a detection component is provided in the return light output direction of each optical path section 1 of the optical fiber optical path, and the detection component includes a temperature detection device and / or an optical power detection device 2.

[0035] The return light outputted by the return light output optical fiber will be received and detected by the optical power detection device 1, so that the return light data can be obtained. The optical power detection device 1 adopts the monitoring sensor M1, and the return light outputted by the return light output optical fiber will hit the monitoring sensor M1, so that the magnitude of the return light power can be accurately monitored in real time. At the same time, a PD (photodiode) and a temperature sensor are arranged on the optical path section 1 and / or the optical path section 2 3. The PD is used to convert the detected optical signal into an electrical signal, and the temperature sensor is used to detect the temperature of the optical fiber at the location, so that the temperature and optical power data transmitted between different optical fibers can be monitored to protect the normal operation of the laser.

[0036] In the specific implementation process, the heat conductor is made of quartz glass. Quartz glass is similar to optical fiber material, and by using this material as the material for making the heat conductor, it is easy for the return light entering the cladding to pass through the light output part 1 4 or the light output part 2 5 and enter the heat conductor for filtering and heat output.

[0037] An embodiment of the present application also provides a laser, comprising an optical device for resisting backscattered light according to any of the above technical solutions.

[0038] The optical fiber optical path of the optical device against reflected light is a part of the laser optical path, and is connected to the laser light source through the laser input optical fiber A3, and the optical output end of the optical fiber optical path is connected to the laser head, so that it can be used to filter and detect the reflected light of the laser, which is more convenient and practical. In order to better illustrate the embodiments of the present application, the following embodiments are provided: Embodiment 1: Please refer to Figure 1-Figure 3As shown, the optical fiber optical path includes two optical path sections 1 and one optical path section 2 and a beam combiner A. For the convenience of explanation, the optical filter device 1 of the first optical path section 1 in the input direction to the output direction of the return light of the optical fiber optical path is a first optical filter device C1. The optical fiber in the first optical filter device C1 adopts a 0.22NA 100 / 120 / 360 homogenized optical fiber, which filters the cladding light transmitted back by the return light through the QBH (a kind of laser output head) and homogenizes the core light into a high-order mode. The filtered cladding light is heat-conducted to the cold plate 6 through the first optical filter device C1 for heat dissipation; the optical filter device 1 on the second optical path section 2 in the input direction to the output direction of the return light of the optical fiber optical path is a second optical filter device C2. The optical fiber in the second optical filter device C2 adopts a 0.22NA 50 / 70 / 360 homogenized optical fiber filters out the core light of the 100um fiber core that does not enter the 50um fiber core and further homogenizes the fundamental mode core return light into a high-order mode. The filtered core light is heat-conducted to the cold plate 6 for heat dissipation through the second optical filter device C2 on this section; the optical fiber in the optical filter device C3 on the optical path section 2 3 uses 0.065NA 20 / 400 optical fiber, which filters out the core light of the 0.22NA 50um fiber core that does not enter the 0.065NA 20um fiber core. The filtered core light is heat-conducted to the cold plate 6 for heat dissipation through the optical filter device C3. At this time, most of the return light has been filtered out after the three-level optical filtering. The single output fiber of the combiner A is consistent with the fiber of the optical filter device C3. The return light is divided into three after passing through the combiner A. The return light of the laser input fiber A3 enters the main optical path behind. The two branch fibers are branch fiber A1 and branch fiber A2. The return light output by branch fiber A1 and branch fiber A2 hits the monitoring sensor M1, which can accurately monitor the size of the return light power in real time. At the same time, detection component M2, detection component M3 and detection component M4 are set at the return light output direction of each optical path section. Each group of detection components monitors the temperature and optical power transmitted between different optical fibers through PD (photodiode) and temperature sensor, so as to accurately monitor the power of the return light entering the main optical path and ensure that the laser can continuously process high-reflection materials.

[0039] In order to better illustrate the anti-reflection effect of the embodiment of the present application, a power within 2000W is input into the laser input optical fiber A3 and then hits a high-reflection copper plate after passing through an optical device. The reflected light power data output by branch optical fiber 1 A1 and branch optical fiber 2 A2 are measured at the monitoring sensor M1 and are shown in Table 1 below.

[0040] Table 1:

[0041] As shown in Table 1, the return light can be significantly filtered out by filtering in stages, and the power of the return light entering the main optical path can be accurately monitored to ensure that the laser can continuously process high-reflection materials.

[0042] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An optical device for preventing backlight, characterized in that: include: An optical fiber optical path, wherein the optical fiber optical path comprises at least two optical path sections 1, and the optical fiber of the optical path section 1 is a homogenized optical fiber; A light filtering device 1 is arranged on the optical path section 1, the light filtering device 1 comprises a heat conductor coated on the outer side of the optical fiber on the optical path section 1, and the cladding of the optical fiber inside the heat conductor is provided with a light emitting portion 1 for emitting cladding light; Among them, the core diameter of the homogenizing optical fiber of the multiple optical path sections on the optical fiber optical path decreases in sequence from the optical output end to the optical input end of the optical fiber optical path.

2. An optical device for preventing backlighting as claimed in claim 1, characterized in that: The optical fibers of two adjacent optical path segments one are fusion-spliced, and in the two adjacent optical path segments one, the optical fiber core end face of the optical path segment one with a larger optical fiber core diameter and the optical fiber cladding end face of the optical path segment one with a smaller optical fiber core diameter are alternately arranged in the radial direction to form an incident path between the two for the core light of the high-order mode of the optical path segment one with a larger optical fiber core diameter to be incident on the optical fiber cladding of the optical path segment one with a smaller optical fiber core diameter.

3. An anti-reflection optical device as claimed in claim 1, characterized in that: The optical fiber optical path also includes at least one optical path segment 2 arranged in the light input direction of the optical path segment 1 having the smallest core diameter in the optical path segment 1, the optical path segment 2 is provided with a light filtering device 2 coated on the outside of the optical fiber on the optical path segment 2, the optical fiber cladding on the inner side of the optical filtering device 2 is provided with a light emitting portion 2 for emitting cladding light, and the core diameter of the optical path segment 2 is smaller than the core diameter of the adjacent optical path segment 1.

4. An anti-reflection optical device as claimed in claim 3, characterized in that: The optical fiber NA value of the optical path section 2 is smaller than the optical fiber NA value of the optical path section 1 adjacent to the optical path section 2.

5. An optical device for preventing backlighting as claimed in claim 3, characterized in that: It also includes a cooling component, and the light filtering device 1 and the light filtering device 2 are both arranged on the cooling component.

6. An anti-reflection optical device as claimed in claim 1 or 3, characterized in that: It also includes a beam combiner arranged at the optical input end of the optical fiber optical path, which combines and connects the optical fiber of the optical fiber optical path with a plurality of branch optical fibers, wherein the plurality of branch optical fibers include a laser input optical fiber and a return light output optical fiber.

7. An optical device for preventing backlighting as claimed in claim 6, characterized in that: The optical output direction of the return light output optical fiber is provided with an optical power detection device 1, and the optical fiber optical path is provided with a detection component in the return light output direction of each optical path section 1, and the detection component includes a temperature detection device and / or an optical power detection device 2.

8. An optical device for preventing backlighting as claimed in claim 1, characterized in that: The heat conductor is made of quartz glass.

9. A laser, characterized in that: An optical device for preventing backlighting as claimed in any one of claims 1 to 8.

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