Numerical aperture cladding light strippers with overdraw

Abstract

The present disclosure relates to numerical aperture clad light strippers with excessive tapering. In some embodiments, a clad light stripper can include one or more input optical fibers having an effective input diameter, an output optical fiber having an output diameter, and a light removal section. The light removal section can include a lower taper section and an upper taper section. The lower taper section can taper down the one or more input optical fibers from the effective input diameter to a tapered diameter. The upper taper section, connected to the lower taper section, can taper up the output optical fiber from the tapered diameter to the output diameter. In some examples, an upper taper ratio of the upper taper section and a numerical aperture (NA) of the light removal section can define a NA threshold for cladding light that can propagate through the output optical fiber.

Description

Cross-references to related applications

[0001] This patent application claims priority to U.S. Patent Application No. 63 / 769,702, filed April 29, 2025, entitled “Numerical Aperture Cladding Light Stripper with Over-Tapering.” The disclosure of the earlier application is considered part of this patent application and is incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to cladding optical strippers and optical removal via excessive tapering. Background Technology

[0003] An optical fiber may include a core that carries light and a cladding that surrounds the core and is configured to confine the light within the core. A cladding stripper is used to remove or extract light from the cladding of an optical fiber. Summary of the Invention

[0004] In some embodiments, the cladding light stripper may include one or more input fibers having an effective input diameter; an output fiber having an output diameter; and a light removal section, wherein the light removal section may include a lower tapered section that tapers the one or more input fibers from the effective input diameter to a tapered diameter; and an upper tapered section connected to the lower tapered section that tapers the output fiber from the tapered diameter to the output diameter, wherein the upper tapering ratio of the upper tapered section and the numerical aperture (NA) of the light removal section define an NA threshold for cladding light that can propagate through the output fiber.

[0005] In some embodiments, the cladding light stripper may include an input fiber having an input diameter; an output fiber having an output diameter; and a light removal section, wherein the light removal section may include a lower tapered section that tapers the input fiber from the input diameter to a tapered diameter; and an upper tapered section connected to the lower tapered section that tapers the output fiber from the tapered diameter to the output diameter, wherein the upper tapering ratio of the upper tapered section and the NA of the light removal section define an NA threshold for cladding light that can propagate through the output fiber.

[0006] In some embodiments, an optical fiber system including a cladding light stripper may include a plurality of input optical fibers having an effective input diameter; an output optical fiber having an output diameter; a light removal section including a lower tapered section and an upper tapered section, the lower tapered section tapering the plurality of input optical fibers from the effective input diameter to a tapered diameter, the upper tapered section being connected to the lower tapered section and tapering the output optical fiber from the tapered diameter to the output diameter, wherein the upper tapering ratio of the upper tapered section and the NA of the light removal section define an NA threshold for cladding light that can propagate through the output optical fiber; a light blocker located around a portion of the upper tapered section, the upper tapered section being configured to block a portion of the cladding light escaping from the light removal section from entering the output optical fiber; and a metal housing enclosing the cladding light stripper and being configured to absorb heat from a portion of the cladding light escaping from the light removal section. Attached Figure Description

[0007] Figure 1 A side view of the fiber optic combiner is shown.

[0008] Figure 2 A side view of a cladding light stripper according to one or more embodiments is shown.

[0009] Figure 3 The optical stripping at a cladding optical stripper according to one or more embodiments is shown.

[0010] Figure 4 A cross-sectional view of the housing of a closed cladding optical stripper according to one or more embodiments is shown.

[0011] Figure 5 The illustration shows an example laser system based on one or more implementations. Detailed Implementation

[0012] The following detailed description of the exemplary embodiments is with reference to the accompanying drawings. The same reference numerals in different drawings may identify the same or similar elements.

[0013] In some applications, such as high-power (e.g., kilowatt-level or higher) lasers, lasers may include optical fibers comprising a polymer coating (e.g., a cladding circumferentially surrounding the fiber). The polymer coating may have a low refractive index to guide light within the fiber cladding (e.g., cladding light, in addition to core light propagating within the fiber core). Due to its low melting point, the polymer coating can be considered a weakness in the construction and operation of high-power lasers. For example, the encapsulation process forming a high-power laser may cause the fiber to be manipulated (e.g., bent or twisted), causing high-power light propagating through the fiber to leak uncontrollably from the fiber cladding. This leaked high-power light then overheats the fiber's polymer coating, which degrades the performance of the fiber (and the high-power laser comprising it) and leads to fiber (and high-power laser) failure. Therefore, there is a need to mitigate and / or manage cladding light leakage from the fiber, especially for high-power applications.

[0014] High numerical aperture (NA) cladding light is a common problem in cladding-pumped high-power fiber lasers, where NA cladding light degrades the performance and reliability of the laser system. NA cladding light is light propagating within the cladding of an optical fiber, characterized by an NA exceeding the guiding capability of the fiber core, potentially leading to inefficiencies and heating problems in fiber laser systems. As used herein, a component (or the material of a component) can be described as "having an NA" or "with an NA." This refers to the nature of the interface between the component and another component (e.g., comprising another material) (or air), and is based on the corresponding refractive indices of the component and the other component (or air). The NA of a component characterizes the angular range of light reflected or transmitted at the interface. In a specific example, for an optical fiber, the NA of the fiber describes an angular range within which light incident within the fiber is propagated along the fiber (e.g., within the fiber) rather than leaking out of the fiber. When a component is described as having an NA... X When NA is enabled, the maximum NA that this component can support is... X (For example, to allow total internal reflection within the component). Additionally, as used herein, light (e.g., cladding light) can be described as "having NA," which characterizes the angular range of light propagation (e.g., through an optical fiber). When light is described as having Y At NA, the maximum NA of light is Y .

[0015] In some double- or triple-clad optical fibers, the outer cladding may be made of a low-refractive-index polymer coating, such as silicone or other materials, which serves as an additional layer for guiding light. This outer cladding typically has an NA of approximately 0.48 (although NA can vary, having values ​​ranging from 0.46 to 0.55, or other ranges). When the light's NA exceeds that of the outer cladding, light may enter the outer cladding, causing overheating or even fiber burnout. This is particularly relevant because high-power fiber lasers are designed to operate at elevated power levels, and any inefficiency or damage will severely impact their performance. The problem can also be exacerbated by underlying defects in the fiber system, such as defects caused by fiber splices or bends. These defects may unintentionally generate light with an NA exceeding that of the fiber cladding, also increasing the risk of overheating or burning in the polymer cladding or recoated sections of the fiber. Even when the light's NA is lower than that of the fiber cladding, evanescent waves may still propagate partially within the polymer cladding, causing the cladding to heat up. The higher the NA, the more pronounced this heating effect becomes, threatening the integrity of the optical fiber.

[0016] Some embodiments described herein include laser systems implementing one or more cladding optical strippers with an over-tapered design. For example, the cladding optical stripper may include a connector where one or more input fibers are spliced ​​and connected to an output fiber. According to the over-tapered design, during a lower taper section of one or more input fibers, the diameter of one or more input fibers can be gradually tapered to a smaller diameter, which can be used as the over-tapered diameter. Additionally, this over-tapered diameter can be smaller than the diameter of the output fiber, such that the output fiber includes an upper taper section spliced ​​to the lower taper section, where the fiber diameter gradually tapers to the diameter of the output fiber. In some embodiments, the lower taper section may be associated with a taper ratio (TR), which indicates the factor by which the diameter of one or more input fibers is over-tapered. Furthermore, the value of TR may define an NA threshold, where light from one or more input fibers having an NA higher than the NA threshold can escape from or permeate the cladding optical stripper during the lower taper section. Therefore, the TR of the lower cone section and / or the TR of the upper cone section can be configured to limit the NA threshold to remove NA cladding light before it enters the output fiber, thereby reducing the possibility of fiber burnout and improving the reliability of the laser system.

[0017] Thus, some implementations allow for the selective stripping of a specific range of unwanted cladding light's near-field (NA) from the optical fiber. When used in high-power applications, this reduces the likelihood of high-power cladding light leakage (e.g., in areas associated with splices or other points where high NA cladding light may be present) and overheating of the output fiber's coating. Therefore, implementations of over-tapered optical strippers improve the performance of the optical output fiber and reduce the likelihood of output fiber failure. Furthermore, this thereby improves the performance of laser systems comprising the cladding optical stripper and the output fiber, and reduces the likelihood of laser system failure.

[0018] Figure 1 A side view of an optical fiber combiner 100 is shown. The optical fiber combiner 100 includes one or more input optical fibers 102, a tapered section 104, and an output optical fiber 106.

[0019] One or more input optical fibers 102 (e.g., denoted as) N One optical fiber, of which " N The term "input fiber 102" (referring to the number of individual input fibers 102) can include multiple fibers combined together to transmit or receive optical signals. The fiber can be a flexible, transparent wire (e.g., made of glass, plastic, or other materials) designed to transmit light from one end to the other. This transmission occurs through the principle of total internal reflection. Total internal reflection occurs when light propagating within a medium with a higher refractive index (such as the core of an optical fiber) strikes the boundary of a medium with a lower refractive index (such as the cladding) at an angle greater than the critical angle. At this point, all the light is reflected back into the medium with the higher refractive index, rather than through the boundary, thus allowing for efficient confinement and guidance of light within the fiber. Because optical fibers can carry large amounts of data or power in the form of light, they can be used in telecommunications, medical devices, and industrial applications. For example, one or more input fibers 102 can be configured to transmit high-power beams (e.g., greater than 200 watts (W), greater than 1 kilowatt (kW), or even greater than 10 kW), which can be used for material handling and other industrial purposes. In these settings, the high-power beam can be used for material cutting, welding, and / or surface treatment, where precise and robust energy transfer is necessary.

[0020] For several reasons, multiple input optical fibers 102 can be used in a system. For example, using multiple input optical fibers 102 allows for the distribution of optical power among several channels, reducing the risk of damage to individual fibers and increasing the reliability of the entire system. Additionally or alternatively, multiple input optical fibers 102 can allow for the combination or multiplexing of different light sources, wavelengths, or beam distributions, thereby providing greater flexibility and control over the transmitted beam. Additionally or alternatively, in high-power applications, distributing power across several fibers helps manage thermal loads and avoid nonlinear optical effects that could degrade system performance. This multi-fiber approach ensures the safe, efficient, and scalable transmission of high-power optical energy for demanding industrial tasks. Although Figure 1 A set of input optical fibers 102 comprising 19 input optical fibers 102 is shown, but in other embodiments, the set of input optical fibers 102 may include any number of input optical fibers 102 (e.g., one input optical fiber or any other number).

[0021] The output fiber 106 may be a single fiber spliced ​​to the set of input fibers 102, serving as a conduit for transmitting combined optical power from multiple inputs to a target application. The splicing process involves physically connecting the ends of the input fibers 102 to the ends of the output fiber 106, such that optical signals from all input fibers 102 are effectively coupled to the core of the output fiber 106. This can be achieved using techniques such as fusion splicing and / or mechanical splicing, in which heat is applied to melt and fuse the glass ends together, and in which the input fibers 102 and output fibers 106 are aligned and held in place by clamps. In some embodiments, the ends of the input fibers 102 are arranged and aligned with the core 108 of the output fiber 106 to reduce optical loss and ensure that most of the light from each input fiber 102 is transmitted into the output fiber 106.

[0022] Both the input fiber 102 and the output fiber 106 may include a core 108, which may be the central region of the fiber responsible for guiding most of the optical signal. The core 108 may include high-purity glass or plastic with a refractive index higher than the surrounding layers, allowing the core 108 to confine light through total internal reflection. For example, the input fiber may have a core 108a, while the output fiber 106 may have a core 108b. These cores 108 can be designed to optimize optical transmission, ensuring efficient guidance of light along the length of the fiber with minimal loss.

[0023] Around the core 108, the optical fiber may include one or more cladding layers. A cladding layer is a layer of material with a lower refractive index than the core 108, used to further confine light within the core 108 by reflecting stray light back into the core 108, thereby enhancing the efficiency and performance of the optical fiber. Specifically, the outer cladding 110 may be the outermost cladding layer surrounding the core 108 (and any inner cladding), providing structural integrity and additional optical isolation. The outer cladding 110 may include glass, such as silica, or a polymeric material chosen for its durability and compatibility with the core 108. For example, an input fiber 102a from a plurality of input fibers 102 may have an outer cladding 110a, while an output fiber 106 may have an outer cladding 110b. These outer cladding layers 110 help maintain signal quality, protect the core 108 from physical damage, and prevent optical power loss during transmission.

[0024] In addition to the core 108 and the outer cladding 110, the optical fiber may also include one or more inner claddings 112 (such as double-clad or triple-clad fibers). These inner claddings 112 may be concentric regions surrounding the core 108 and located between the core 108 and the outer cladding 110. One or more inner claddings 112 may be used to enable advanced optical functions, such as supporting higher power transmission or enabling the collection and guidance of pump light in fiber lasers and amplifiers. In some embodiments, the inner claddings 112 may comprise glass or polymer materials with a specifically designed refractive index. For example, the refractive index of each inner cladding 114 may be lower than that of the core 108, but may also be higher or lower than that of the outer cladding 110, depending on the fiber design. For example, in a double-clad fiber, the core 108 (with the highest refractive index) is surrounded by a first inner cladding (with a lower refractive index than the core 108) and then surrounded by an outer cladding 110 (with the lowest refractive index). This arrangement allows core 108 to guide the main optical signal, while the (multiple) inner cladding layers can guide pump light or additional modes, enhancing the fiber functionality for high-power or specialized optical applications.

[0025] To facilitate this transition from the input fiber 102 to the output fiber 106, a tapered section 104 can be introduced at the connection between the input fiber 102 and the output fiber 106. In this arrangement, the bundle of multiple input fibers 102 initially has a diameter 116 larger than that of the output fiber 106 (e.g., ...). ) effective input diameter 114 (e.g. ).for N One fiber input fiber bundle ( ), where each input fiber has the same cladding diameter ( The effective input diameter of the input fiber bundle is 114 ( According to Equation 1: (1)

[0026] The tapered section 104 is used to gradually reduce the effective input diameter 114, smoothly guiding the combined optical signal from the larger beam into the smaller core 108 of the output fiber 106. The tapered section 104 can be formed by heating and stretching the input fiber 102, causing the input fiber 102 to narrow over a certain length, allowing for an adiabatic transition in which the optical mode is adapted from multiple input fibers 102 to a single output fiber 106.

[0027] In addition, the taper ratio of the tapered section 104 ( TR ) can be based on an effective input diameter of 114 ( ) and output fiber optic 106 ( The cladding diameter, according to Equation 2: (2)

[0028] In some examples, the input fiber 102 and the output fiber 106 may be associated with or have an NA value. The NA of the input fiber 102 and the output fiber 106 is an optical characteristic that determines how effectively each fiber captures, confines, and transmits light. NA is related to the refractive index difference between the fiber core 108 and one or more adjacent claddings, and it defines the range of incident angles at which light can enter the fiber and still be guided along its length. When referring to the “maximum angle” in the context of NA and fiber, the angle is measured relative to the fiber axis (e.g., the central or longitudinal axis of the fiber). This axis extends along the length of the fiber, and the maximum angle describes how steeply light enters or propagates into the core (relative to this axis) while still being totally internally reflected and guided through the fiber. If the angle between the light and the fiber axis exceeds this maximum value (determined by NA), the light will not be confined by total internal reflection and may escape from the core or cladding. In other words, NA characterizes the receiving taper of the fiber (e.g., the larger the NA, the wider the range of angles at which light can successfully enter and propagate through the fiber without escaping through the cladding). For both the input fiber 102 and the output fiber 106, the NA is thus defined by the interface between the core 108 and the surrounding cladding, or by the interface between the fiber and the external environment, such as air. This means that, depending on the specific refractive index of the materials used in the core 108 and the cladding, different fibers can be designed to have higher or lower NAs. Higher NAs can be used to collect light from sources with a wide emission angle range, or to emit high-power beams. Conversely, lower NAs result in a narrower reception angle, which is beneficial for reducing modal dispersion and improving signal fidelity in telecommunications applications. Therefore, the selection of the NA for the input fiber 102 and the output fiber 106 can be matched to the characteristics of the optical system, taking into account factors such as alignment tolerances, power handling, and the intended application, whether it is industrial material handling or precision optical communication.

[0029] Light propagating through the input fiber 102 can take several paths, such as through the core 108 and also through the cladding (a phenomenon known as "cladding light"). Cladding light is light energy that propagates within the cladding of the fiber, rather than being strictly confined to the core 108. Cladding light can occur in double-clad or multi-clad fibers, where the cladding is intentionally designed to guide light, such as pump light in fiber lasers or amplifiers. Cladding light can be less confined than core-guided light and can travel a longer path within the fiber, interacting with the core 108 or being absorbed elsewhere as part of the fiber's function. Similar to core-guided light, cladding light can also be characterized by its NA (Not Detectable) value. Based on the refractive index of the cladding and surrounding materials, the NA associated with cladding light defines the range of angles within the cladding from which the light can propagate without escaping. When light is described as having a specific NA (e.g., ...), the NA is used to define the angular range within which the light can propagate without escaping. Y When the maximum NA is reached, this means that light passing through the cladding does so within a certain angular range, but not exceeding the maximum NA.Y The angle corresponding to NA. In other words, the cladding light can pass through the input fiber 102 in the spectrum of NA, up to and including... Y The maximum NA.

[0030] Additionally, the NA2 of the light entering fiber 10 ( ) and the NA of the light within the output fiber 106 The relationship between them can be based on the taper ratio ( TR The value of ) is determined according to Equation 3: (3)

[0031] As described in Equation 3, when the input fiber 102 is tapered to match the output diameter 116 of the output fiber 106, the NA of the light emitted from the input fiber 102 increases proportionally to the taper ratio. This is because tapering the fiber reduces the cross-sectional area through which light propagates, effectively compressing the optical mode. As a result, the angle at which light propagates within the fiber becomes steeper relative to the fiber's axis. Since NA is a measurement of the maximum angle at which light can be guided within the fiber, reducing the fiber diameter by tapering increases the angle range, thus increasing NA by a factor equal to the taper ratio.

[0032] exist Figure 1 In the context of this paper, equations 1 to 3 can be used to describe the output fiber 106 ( The resulting NA (Number of Attenuation) within the light source may lead to a reduction in power processing capability, as shown in the example value. Figure 1 As shown, there are 19 input optical fibers 102 (e.g. =19), with a cladding diameter of 220 micrometers (μm) for each input fiber (e.g. =220μm), and the cladding diameter of the output fiber 106 is 400μm (e.g., 220μm). =400μm), the NA of the outer cladding 110b of the output fiber 106 is 0.48. Therefore, the taper ratio of the tapered section 104 ( TR The NA of the input light can be approximately 2.397. Additionally, in some implementations of laser diodes (such as high-power laser diodes), the NA of the input light can be 0.22 or higher (e.g., ...). ≥0.22). In the first example, if the NA of the portion of the input light is 0.22 (e.g., =0.22), then the NA of the light in the output fiber 106 can be 0.527 (e.g., ≥0.527), which is greater than the NA of the outer cladding 110b of the output fiber 106 (e.g., 0.48). In Figure 1In this case, because 0.527 > 0.48, some of the light in the output fiber 106 may leak through the outer cladding 110 of the output fiber 106 (e.g., leaked light 118), causing heat generation and reducing power handling capability.

[0033] Such leaked light 118 can cause one or more problems. For example, when high-power light escapes from the fiber, the leaked light 118 can deposit energy into the coating or surrounding material of the output fiber 106, causing localized heating. Over time, this heating can damage the output fiber 106, leading to fiber burning, melting, and / or fiber structural failure. In high-power applications, such as industrial laser transmission systems, this damage to the output fiber 106 reduces power transmission efficiency and may increase safety risks, including the possibility of fire or damage to nearby equipment. Additionally, the leaked light 118 may degrade the overall optical performance of the system. The escaping leaked light 118 represents a loss of transmitted power, reducing the efficiency of light transmission from the output fiber 106. Furthermore, uncontrolled emission of high-intensity light from the output fiber 106 can generate stray beams or scattered light, which may cause optical noise, interfere with surrounding instruments, and / or pose a hazard to operators.

[0034] Figure 1 Provided as an example. Other examples may differ from those provided. Figure 1 The example described.

[0035] Figure 2 A side view of a cladding optical stripper 200 according to one or more embodiments is shown. In some aspects, the cladding optical stripper 200 may implement one or more aspects of the fiber combiner 100. For example, as Figure 2 As shown, the cladding optical stripper 200 includes one or more input optical fibers 102 having an effective input diameter 114 and being connected to an output optical fiber 106 having an output diameter 116.

[0036] Additionally, the cladding optical stripper 200 includes an optical removal section 202. For example, the optical removal section 202 may include a lower conical section 204 and an upper conical section 206. Figure 2As shown, the lower tapered section 204 tapers one or more input optical fibers 102 from an effective input diameter 114 to a tapered diameter at the connector 214, where the tapered diameter is smaller than the effective input diameter 114. Additionally, the upper tapered section 206, connected to the lower tapered section 204 at the connector 214, tapers the output optical fiber 106 from a tapered diameter to an output diameter 116, where the tapered diameter is smaller than the output diameter 116. In other words, the light removal section 202 includes a connector 214 where one end of the lower tapered section 204 is connected to the beginning of the upper tapered section 206, where one or more input optical fibers 102 are spliced ​​to the output optical fiber 106.

[0037] In some implementations, the taper diameter may be smaller than the output diameter 116, and the output diameter 116 may be less than or equal to the effective input diameter 114. As described herein, the input fiber bundle may include any number of input fibers 102. For example, in an implementation where the group of input fibers 102 includes a single input fiber (e.g., input fiber 102a), the effective input diameter 114 becomes the cladding diameter of the single input fiber.

[0038] According to the technique described herein, the lower tapered section 204 can be excessively tapered (e.g., with an increased taper ratio), such that the end of the lower tapered section 204 at the connector 214 is smaller than the output diameter 116 of the output optical fiber 106. Additionally, the output optical fiber 106 can also be derived from the output optical fiber 106 ( The end portion of the output diameter 116 is tapered to a gradually thicker diameter (e.g., upper taper). In some embodiments, the combination of the tapered input fiber 102 and the upper taper of the output fiber 106 allows the cladding light stripper 200 to remove light with a high NA (e.g., NA higher than the NA threshold provided herein) before it enters the output fiber 106. In other words, the light removal section 202 allows the cladding light stripper to remove high NA cladding light 216 before it enters the output fiber 106.

[0039] The cladding optical stripper 200 illustrates an over-tapered lower tapered section 204 and an upper tapered output fiber 106. In one example, the cladding optical stripper 200 may include 19 input fibers 102 (e.g., ...). =19), where the cladding diameter for each input fiber is 220 μm (e.g., =220μm), and the output fiber 106 has 400μm (e.g., =220μm), The cladding diameter is 400 μm, and the NA of the cladding of the output fiber 106 is 0.48. It is not a gradual tapering of the lower taper section 204 to the output diameter 116 of the output fiber 106 (e.g., as shown in the image). Figure 1Instead of the previously mentioned method, the lower tapered section 204 is gradually tapered to a diameter of 180 μm. Therefore, the effective diameter of the input fiber 102 is approximately 5.327 times the diameter of the tapered section. Additionally, the light with a wavelength of 0.22 NA in the input fiber 102 before tapering gradually decreases in diameter after tapering to the excessive tapering diameter. The light stripper can have an NA of 1.17. Additionally, the outer cladding of the light stripping section 202 can be air, making the outer cladding NA of the light stripping section 202 approximately 1.05. Because 1.17 > 1.05, light with an NA of 0.22 before tapering can escape from the input beam after tapering (e.g., the light will not reach the output fiber 106). In other words, high-NA cladding light 216 can escape from the cladding stripper 200 before entering the output fiber 106. Furthermore, as... Figure 2 As shown, the output fiber 106 is gradually thickened from a tapered diameter of 180 μm to an output diameter 116 of 400 μm. After the gradual thickening and tapering, the maximum NA of the light entering the output fiber 106 can be equal to the outer cladding NA of the light removal section 202 multiplied by the ratio between the tapered diameter at the connector 214 and the output diameter 116 (e.g., ...). Because the highest possible NA value for the light entering the output fiber 106 is less than the NA of the cladding of the output fiber 106 (e.g., 0.47 < 0.48), the light entering the output fiber 106 will not be able to pass through the outer cladding 110b of the output fiber 106. Therefore, the NA of the light removal segment 202 ( ), cone diameter ( ) and output diameter 116 ( The value of ) can be configured such that the highest NA of the light entering the output fiber 106 is less than the NA of the outer cladding 110b of the output fiber 106. According to Equation 4: (4)

[0040] According to formula 4, and The smaller the ratio, the lower the permissible output NA for the light entering the output fiber 106 (assuming no degradation during tapering). Therefore, the upper taper ratio of the upper taper section 206 ( (For example, among them) ) and the NA of the light removal section 202 ( ) limits the allowable level of cladding light that can propagate through the output fiber 106 to the NA threshold (e.g. For example, the NA threshold is defined according to Equation 5 (). The value of ) (5)

[0041] In other words, Equation 5 defines the NA threshold as equal to the NA of the light removal segment 202 divided by the upper taper ratio, where the upper taper ratio is equal to the output diameter 116 divided by the taper diameter. According to Equations 4 and 5, the NA threshold is configured to be less than the NA of the outer cladding 110b of the output fiber 106. )(For example Additionally, one or more input fibers 102 are configured to propagate cladding light to output fiber 106. For example, the cladding light has an NA distribution, wherein a portion of the cladding light is associated with an NA greater than an NA threshold (e.g., high NA cladding light 216) after moving through the lower cone segment 204. Therefore, the light removal segment 202 is configured to remove the portion of cladding light associated with NAs greater than the NA threshold.

[0042] In some embodiments, the lower conical section 204 and the upper conical section 206 are enclosed by a glass material surrounded by air, and the NA of the light removal section 202 can be based on the refractive index of the glass material and the refractive index of air. For example, the portion of the input fiber 102 spanning the lower conical section 204 and the portion of the output fiber 106 spanning the upper conical section 206 can be stripped of any cladding, such that the core 108 of the input fiber 102 and the output fiber 106 are in direct contact with the surrounding air. In other words, air serves as an outer cladding for one or more input fibers 102 and output fibers 106, such that in the light removal section 202, the core 108 of the input fiber 102 and the output fiber 106 (e.g., glass material) is surrounded by air (e.g., an outer cladding). Therefore, the NA of the light removal section 202 ( ) can be based on the refractive index of the glass material of core 108 (e.g. ) and the refractive index of air (e.g. According to Equation 6: (6) For example, according to Equation 6, if the refractive index of the fiber core 108 is 1.45 and the refractive index of the surrounding air is 1, then the light removal segment 202 has a NA ( The value is approximately 1.05, as used above. The outer cladding of the light removal section 202 can be air, so that the high NA cladding light 216 escaping from the light removal section 202 will not burn through any coating material.

[0043] As described herein, the TR of the lower cone segment 204 and / or the upper cone segment 206 can be configured to remove light with an NA higher than a configured NA threshold. In some examples, the TR of the lower cone segment 204 and / or the upper cone segment 206 can be based on the allowable NA level for light from the input fiber 102 ( ), and the NA of the light removal section 202 ( According to Equation 7: (7)

[0044] For example, if the cladding optical stripper 200 is configured to remove NA greater than 0.21 from the input fiber 102 (e.g., The light, and the outer cladding NA of the light removal segment 202 is 1.05 (e.g., the light that removes the NA). =1.05), then TR equals 5 ( Therefore, any light with an NA higher than 0.21 from the input fiber 102 will be greater than 1.05 after tapering, thus escaping from the cladding light stripper 200 (e.g., as part of the high NA cladding light 216). Similarly, if the cladding light stripper 200 is configured to remove light with an NA higher than 0.15 (e.g., from the input fiber 102 (or an input fiber bundle comprising multiple input fibers 102)... The light, and the NA of the light removal portion 202 is 1.05 (e.g.) =1.05), then TR equals 7 (for example, Therefore, any light with a value higher than 0.15 from the input fiber 102 will be greater than 1.05 after tapering, thus escaping from the cladding light stripper 200 (e.g., as part of the high NA cladding light 216).

[0045] like Figure 2 As shown, the cladding light stripper also includes a light blocker 212. The light blocker 212 may be located around a portion of the upper cone section 206, and the light blocker 212 may be configured to block a portion of the cladding light (e.g., high NA cladding light 216) escaping from the light removal section 202 from entering the output fiber 106. The light blocker 212 may be made of a material that effectively absorbs light energy, thereby preventing the high NA cladding light 216 from further propagating into the fiber optic system. Suitable materials for the light blocker 212 include metals such as stainless steel, copper, aluminum, and / or metal alloys designed for high thermal conductivity and optical absorption (e.g., materials with thermal conductivity thresholds and / or materials with optical absorption coefficient thresholds). In some embodiments, the light blocker 212 may include ceramics, composite materials, or engineered polymers that are treated or coated with light-absorbing substances, such as blackened or anodized surfaces, to enhance their absorption properties and minimize reflection.

[0046] Although light blocker 212 is in Figure 2While depicted as having a ring shape, the shape of the light blocker 212 is not limited to this geometry. The light blocker 212 can take on various shapes and configurations (such as sleeves, partial housings, patches, or segmented structures) as long as it effectively blocks and absorbs the high-NA cladding light 216 escaping from the light removal section 202. The design of the light blocker 212 can be customized based on the specific distribution and propagation path of the cladding light, as well as the mechanical and thermal properties of the fiber optic components.

[0047] like Figure 2 As shown, the lower conical segment 204 has a first length 208, and the upper conical segment 206 has a second length 210. The lengths of these conical segments and the resulting conical slopes can be optimized to control how and where the high-NA cladding light 216 is dissipated. For example, by extending the first length 208 and / or the second length 210, the high-NA cladding light 216 can be gradually stripped from the cladding light stripper 200 and absorbed over a longer distance, which helps to distribute the resulting heat more evenly and reduces the risk of localized overheating or thermal damage to the cladding light stripper 200 and / or surrounding components. Specifically, the first length 208 and the second length 210 can be defined such that the temperature of the light removal segment 202 (e.g., caused by the absorption of portions of the cladding light escaping from this region) meets a predetermined temperature threshold. This threshold can be established to ensure safe operation and protect the integrity of the fiber optic components, preventing problems such as fiber burnout, coating degradation, and / or shielding material failure. By optimizing both the taper slope and the overall dimensions of the taper section, the cladding stripper 200 can effectively manage the thermal load associated with high-power cladding light, improving the performance and reliability of the fiber optic system.

[0048] Figure 2 Provided as an example. Other examples may differ from those provided. Figure 2 The example described.

[0049] Figure 3 A light stripping 300 at a cladding light stripper according to one or more embodiments is shown. For example... Figure 3 As shown, optical stripping 300 can be implemented at and / or performed by cladding optical stripper 200.

[0050] Figure 3 The illustration shows how low-NA light 302 continues to exit fiber 106 after light removal section 202, while high-NA light 304 escapes in lower cone section 204. In some examples, low-NA light 302 may be light whose NA is less than or equal to an NA threshold when passing through connector 214. (The light.) For example, such as... Figure 3 As shown, the low-NA light 302 can have a sidewall relative to the lower cone segment 204. θ1 Angle, among which θ 1 The value is less than or equal to θ 1 The low NA corresponds to the low NA. Therefore, the low NA light 302 can remain in the fiber core of the light removal section 202 and continue to pass through the output fiber 106.

[0051] Conversely, when passing through the lower cone segment 204, the high NA light 304 can be NA greater than the NA threshold ( (The light.) For example, such as... Figure 3 As shown, at the point where the high-NA beam 304 passes through the sidewall of the lower cone section 204, the high-NA beam 304 has a relative position to the sidewall. θ 2 Angle, among which θ 2 The value and greater than The NA corresponds to this. Therefore, high NA light 304 can penetrate to the outside of the fiber core of the light removal section 202, and thus can not enter the output fiber 106.

[0052] Figure 3 Provided as an example. Other examples may differ from those provided. Figure 3 The example described.

[0053] Figure 4 A cross-sectional view 400 of the housing 402 of a closed cladding light stripper according to one or more embodiments is shown. Figure 3 As shown, the outer shell 402 can enclose the cladding light stripper 200.

[0054] A housing 402 is provided to enclose the cladding light stripper 200 and can be designed to absorb heat generated by cladding light (e.g., high-NA cladding light 216) escaping from the light removal section 202. The housing 402 can function as a heat sink, effectively dissipating heat to maintain the stability and lifespan of the input fiber 102 and the output fiber 106. The housing 402 can be constructed from a material with high thermal conductivity (e.g., thermal conductivity meeting a threshold), such as metals like aluminum or copper, and / or metal alloys like stainless steel, to absorb and diffuse heat. Additionally or alternatively, depending on the specific application of the cladding light stripper 200, the housing 402 can be made from other heat-absorbing materials, such as graphite composites, ceramics, and / or thermally conductive polymers. Therefore, the housing 402 can manage the heat generated by the absorbed cladding light, ensuring reliable operation and protecting sensitive fiber components.

[0055] The housing 402 can be designed to circumferentially enclose the cladding light stripper 200 along its longitudinal axis, which is perpendicular to the longitudinal axis of the cladding light stripper 200. xAxial alignment. In other words, housing 402 can surround cladding light stripper 200 from all sides, providing a protective and heat-absorbing barrier around all or part of the length of cladding light stripper 200. Depending on specific design parameters and / or space constraints, housing 402 can take the form of any three-dimensional prism, such as a rectangular or cylindrical structure. Additionally, housing 402 features a through-hole extending parallel to the longitudinal axis, wide enough to accommodate cladding light stripper 200, ensuring the closure of cladding light stripper 200 without hindering functionality. This geometry allows housing 402 to both protect cladding light stripper 200 and effectively absorb heat from any escaping cladding light, while also allowing integration into larger optical components.

[0056] Within the housing 402, the input fiber 102 and the output fiber 106 can be securely fixed in place (e.g., using anchoring material 404, such as glue or other suitable adhesive). By anchoring these fibers at designated points within the housing 402, the light removal section 202 of the cladding light stripper 200 can be effectively suspended in the air, rather than in direct contact with the internal surface of the housing 402. This suspension configuration can be advantageous because suspending the light removal section 202 allows cladding light to effectively penetrate from the cladding light stripper 200 into the surrounding air within the housing 402. Therefore, the air gap around the light removal section 202 reduces reflections and enhances the efficiency of cladding light removal, while the fixed positioning of the fibers ensures mechanical stability.

[0057] Cooling component 406 can be attached to the exterior of housing 402 to ensure effective thermal management by maintaining the temperature of housing 402 at a specified temperature threshold. Depending on cooling requirements and operating environment, cooling component 406 can take various forms. For example, a passive heat sink made of finned aluminum or copper can be mounted to housing 402 to increase surface area and promote natural air convection for heat dissipation. Alternatively or additionally, an active cooling solution such as a thermoelectric cooler (TEC) can be integrated to provide precise temperature control by actively transferring heat away from housing 402. Alternatively or additionally, a liquid cooling jacket or coil can be wrapped around housing 402, allowing coolant to circulate through a closed-loop system for efficient heat absorption and removal. Other examples include attaching a forced-air fan to direct airflow through housing 402 or embedding a phase change material that absorbs excess heat as it melts. By selecting an appropriate cooling component 406, the system can reliably maintain housing 402 within the desired temperature range, protecting fiber optic components and ensuring consistent performance.

[0058] Figure 4 This is provided as an example. Other examples may be provided related to... Figure 4 The descriptions are different.

[0059] Figure 5 An example laser system 500 according to one or more embodiments is illustrated. In some examples, the laser system 500 may implement a cladding optical stripper 200. In some examples, the laser system 500 may include or be an example of one or more high-power cladding-pumped fiber lasers (e.g., fiber lasers reaching a power of 100 kW or greater). To achieve high-power output, multiple laser diodes 504 may be combined as inputs to a single output fiber.

[0060] The laser system 500 can be configured to deliver the optical power of the input signal 502 with high efficiency and high precision. At the heart of the system can be multiple laser diodes 504 serving as the main pump source. These diodes 504 emit light of specific wavelengths and are selected for high output power and efficiency. Figure 5 As shown, the light emitted from these diodes 504 can be directed to a pump signal combiner (PSC) 506a for forward pumping. The PSC 506a can be a component that combines the optical power from multiple laser diodes 504 into a single optical fiber, thereby ensuring that the maximum amount of pump light is delivered to the laser system 500.

[0061] Following the forward pump stage, the laser system 500 may include an oscillator 508, which can be responsible for generating the initial laser signal. The oscillator may include a doped fiber (such as ytterbium-doped fiber), which provides the gain medium capable of generating laser light. The oscillator establishes basic laser beam characteristics, such as wavelength and coherence, which are then amplified in subsequent stages.

[0062] The laser signal can then be cascaded pumped using PSC 506b. This stage involves an additional pump diode 504, which further increases the power of the laser signal by injecting more pump light into the laser system 500. Cascaded pumping technology enhances the efficiency and output power of the laser system 500 by utilizing multiple stages of amplification.

[0063] Amplifier 510 follows a cascaded pump stage, in which the laser signal undergoes power amplification. Amplifier 510 may include a length of doped fiber that provides additional gain to the laser signal, boosting the power of the laser signal to a configured level.

[0064] To further enhance efficiency and output power, the laser system 500 can employ a PSC for reverse pumping. In this configuration, additional pump light can be introduced via the PSC 506c in the opposite direction to the laser signal, thereby providing further amplification and enabling a uniform gain distribution along the fiber. This reverse pumping technique contributes to achieving higher output power and improved beam quality.

[0065] Following reverse pumping, the amplified laser signal exits the laser system 500 as laser output 512. This output is characterized by high power, beam quality, and stability. The combination of forward and backward pumping, along with cascaded amplification, ensures that the laser system 500 operates at peak efficiency and delivers optimal performance.

[0066] In some embodiments, one or more portions of the laser system 500 may increase the NA (such as during forward pumping, cascade pumping, and / or backward pumping). Therefore, the laser system 500 may include one or more cladding optical strippers (e.g., cladding optical stripper 200) at one or more portions of the laser system 500 to reduce the NA of the light leaving the laser output. Thus, including one or more cladding optical strippers can effectively remove light with an NA higher than the NA threshold configured by the cladding optical stripper, reducing the likelihood of light penetrating through the cladding of downstream optical fibers.

[0067] Figure 5 Provided as an example. Other examples may differ from those provided. Figure 5 The example described.

[0068] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations can be made based on the foregoing disclosure, or modifications and variations can be derived from practice of the embodiments. Furthermore, any embodiments described herein can be combined unless the foregoing disclosure expressly provides a reason why one or more embodiments may not be combined.

[0069] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. Clearly, the systems and / or methods described herein can be implemented in various forms of hardware, firmware, or combinations of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods is not a limitation on the implementation. Therefore, this document describes the operation and behavior of systems and / or methods without reference to any specific software code—it should be understood that software and hardware can be designed to implement systems and / or methods based on the description herein.

[0070] As used in this article, depending on the context, a threshold can refer to a value that is greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, etc.

[0071] Even if a particular combination of features is recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various embodiments. In fact, many of these features can be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various embodiments includes each dependent claim in combination with all other claims in the claim set. As used herein, the phrase “at least one” in the list of items refers to any combination of those items, including a single member. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical items.

[0072] When a component or one or more components (e.g., a laser emitter or one or more laser emitters) is described or required (within a single claim or across multiple claims) to perform or be configured to perform multiple operations, this language is intended to broadly cover a wide range of architectures and environments. For example, unless otherwise expressly stated (e.g., by using "first component" and "second component" or other language distinguishing components in the claims), this language is intended to cover a single component that performs or is configured to perform all operations, a group of components that jointly perform or are configured to perform all operations, a first component that performs or is configured to perform a first operation and a second component that performs or is configured to perform a second operation, or any combination of components that perform or are configured to perform operations. For example, when a claim has "one or more components are configured to: perform X; perform Y; perform Z", the claim should be interpreted as meaning "one or more components configured to perform X; one or more (possibly different) components configured to perform Y; and one or more (possibly different) components configured to perform Z".

[0073] Elements, actions, or instructions used herein should not be construed as critical or necessary unless explicitly stated otherwise. Furthermore, as used herein, the articles “a” and “an” are intended to include one or more items and are interchangeable with “one or more.” Furthermore, as used herein, the article “the” is intended to include one or more items associated with the article “the” and is interchangeable with “the one or more.” Furthermore, as used herein, the term “group” is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and is interchangeable with “one or more.” Where only one item is referred to, the phrase “only one” or similar language is used. Furthermore, as used herein, the terms “has,” “have,” “having,” etc., are intended to be open-ended terms. Furthermore, the phrase “based on” is intended to mean “at least partially based on” unless explicitly stated otherwise. Furthermore, as used herein, the term “or” is intended to be inclusive when used in series and is interchangeable with “and / or” unless otherwise explicitly stated (e.g., if used in combination with “any” or “only one”). Additionally, spatially relative terms such as “below,” “lower,” “above,” “upper,” etc., may be used herein to describe the relationship between one element or feature as shown in the figures and another element(s)(s). Apart from the orientations shown in the figures, spatially relative terms are intended to cover different orientations of the device, apparatus, and / or element in use or operation. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatially relative descriptors used herein shall be interpreted accordingly.

Claims

1. A cladding optical stripper, comprising: One or more input optical fibers having an effective input diameter; The output optical fiber has an output diameter; as well as Light removal section, wherein the light removal section includes: The lower conical section gradually tapers the one or more input optical fibers from the effective input diameter to a conical diameter; as well as An upper tapered section is connected to the lower tapered section, the upper tapered section tapering the output fiber from the tapered diameter to the output diameter, wherein the upper tapering ratio of the upper tapered section and the numerical aperture (NA) of the light removal section define an NA threshold for cladding light to propagate through the output fiber.

2. The cladding light stripper of claim 1, wherein the one or more input fibers are configured to propagate the cladding light to the output fiber, and wherein: The cladding light has an NA distribution. A portion of the cladding light is associated with an NA greater than the NA threshold, and The light removal section is configured to remove the portion of the cladding light associated with an NA greater than the NA threshold.

3. The cladding optical stripper according to claim 1, wherein the output optical fiber includes an outer cladding, and wherein the NA threshold is less than the NA of the outer cladding.

4. The cladding light stripper of claim 1, wherein the lower cone section and the upper cone section are enclosed by a glass material surrounded by air, and wherein the NA of the light removal section is based on the refractive index of the glass material and the refractive index of the air.

5. The cladding stripper of claim 1, wherein the upper taper ratio is equal to the output diameter divided by the taper diameter, and wherein the NA threshold is equal to the NA of the light removal segment divided by the upper taper ratio.

6. The cladding optical stripper of claim 1, wherein the optical removal section includes a connector at which an end of the lower conical section is connected to the beginning of the upper conical section, and wherein one or more input optical fibers are spliced ​​to the output optical fiber at the connector.

7. The cladding optical stripper according to claim 1, further comprising: A light blocker located around a portion of the upper conical section, wherein the light blocker is configured to block a portion of the cladding light escaping from the light removal section from entering the output optical fiber.

8. The cladding light stripper of claim 1, wherein the metal housing encloses the cladding light stripper and is configured to absorb heat from portions of the cladding light escaping from the light removal section.

9. The cladding stripper of claim 8, wherein a cooling component is attached to the metal housing, and wherein the cooling component is configured to maintain the temperature of the metal housing to meet a temperature threshold.

10. The cladding light stripper of claim 1, wherein the lengths of the lower cone section and the upper cone section are defined such that the temperature of the light removal section caused by a portion of the cladding light escaping from the light removal section satisfies a temperature threshold.

11. The cladding stripper of claim 1, wherein the tapered diameter is smaller than the output diameter, and the output diameter is smaller than or equal to the effective input diameter.

12. A cladding optical stripper, comprising: The input optical fiber has an input diameter. The output optical fiber has an output diameter; as well as Light removal section, wherein the light removal section includes: The lower conical section gradually tapers the input optical fiber from the input diameter to a conical diameter; as well as An upper tapered section, which is connected to the lower tapered section, taperes the output fiber from the tapered diameter to the output diameter, wherein the upper tapered ratio of the upper tapered section and the numerical aperture (NA) of the light removal section define an NA threshold for cladding light to propagate through the output fiber.

13. The cladding light stripper of claim 12, wherein the input fiber is configured to propagate the cladding light to the output fiber, and wherein: The cladding light has an NA distribution. A portion of the cladding light is associated with an NA greater than the NA threshold, and The light removal section is configured to remove the portion of the cladding light associated with the NA that is greater than the NA threshold.

14. The cladding optical stripper of claim 12, wherein the output optical fiber includes an outer cladding, and wherein the NA threshold is less than the NA of the outer cladding.

15. The cladding light stripper of claim 12, wherein the lower cone section and the upper cone section are enclosed by a glass material surrounded by air, and wherein the NA of the light removal section is based on the refractive index of the glass material and the refractive index of the air.

16. The cladding stripper of claim 12, wherein the upper taper ratio is equal to the output diameter divided by the taper diameter, and wherein the NA threshold is equal to the NA of the light removal segment divided by the upper taper ratio.

17. The cladding optical stripper of claim 12, wherein the optical removal section includes a connector at which an end of the lower conical section is connected to the beginning of the upper conical section, and wherein the input optical fiber is spliced ​​to the output optical fiber at the connector.

18. The cladding optical stripper according to claim 12, further comprising: A light blocker located around a portion of the upper conical section, wherein the light blocker is configured to block a portion of the cladding light escaping from the light removal section from entering the output optical fiber.

19. The cladding light stripper of claim 12, wherein the metal housing encloses the cladding light stripper and is configured to absorb heat from portions of the cladding light escaping from the light removal section.

20. An optical fiber system including a cladding light stripper, comprising: Multiple input optical fibers with an effective input diameter; The output optical fiber has an output diameter; The light removal section includes a lower tapered section and an upper tapered section, wherein the lower tapered section tapers the plurality of input optical fibers from the effective input diameter to a tapered diameter, and the upper tapered section is connected to the lower tapered section and tapers the output optical fiber from the tapered diameter to the output diameter, wherein the upper tapering ratio of the upper tapered section and the numerical aperture (NA) of the light removal section define an NA threshold for cladding light to propagate through the output optical fiber; A light blocker, located around a portion of the upper conical section, is configured to block a portion of the cladding light escaping from the light removal section from entering the output optical fiber; as well as A metal casing encloses the cladding light stripper and is configured to absorb heat from the portion of the cladding light escaping from the light removal section.

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