CN217134869U - Reducing optical fiber for high-power optical fiber laser and high-power optical fiber laser - Google Patents

Abstract

The utility model relates to the technical field of laser, the utility model provides a reducing optical fiber for high-power optical fiber laser, which comprises an outer cladding layer, an inner cladding layer and a fiber core which are arranged in sequence along the inner and outer directions, wherein the diameter of the outer cladding layer is uniformly arranged; the fiber core is provided with a pump light incidence section and a middle section, the pump light incidence section is used for incidence of pump light, and the diameter of the fiber core of the pump light incidence section is smaller than that of the fiber core of the middle section. The utility model provides a high power is reducing optic fibre for fiber laser aims at solving the conventional art, and the pump light incident end of optic fibre leads to the temperature to rise because of power change, arouses optic fibre mode instability easily, causes the problem that optic fibre burns out.

Description

Reducing optical fiber for high-power optical fiber laser and high-power optical fiber laser

Technical Field

The utility model relates to a laser technical field especially relates to a high power is reducing optic fibre and high power fiber laser for fiber laser.

Background

From the birth of the first ruby laser to the present, the laser has been moved from theory to practical application, wherein the fiber laser is used as the third generation solid laser, the application covers the laser marking, metal cutting, cladding and cleaning, the traditional industrial processing means is almost replaced, and the fiber laser becomes one of the most potential research hotspots in the laser technical field by virtue of the excellent characteristics of high efficiency, long service life, good beam quality, low loss, high damage threshold, compact appearance structure and the like.

Along with the development of industrial manufacturing and the requirement of national defense application, the power requirement of the fiber laser is higher and higher, and the high-power fiber laser which is more stable and has low energy consumption is manufactured and is the main development direction of the fiber laser at present. The power of the fiber laser is improved mainly from the following aspects: the design of the laser structure, the improvement of the performance of core components such as active optical fibers, the manufacturing process (such as the fusion coating of the optical fibers) and the upgrading of auxiliary manufacturing equipment (such as a cutting knife, a fusion welding machine and the like). Among them, the active fiber is the most important part of the fiber laser, and its structural design has a decisive influence on the beam quality, laser power, slope efficiency, nonlinear effect, mode instability (TMI) and photodarkening effect of the laser. In order to increase the laser power and improve the conversion efficiency, a mode field area is generally increased, however, in the practical application process, the mode field diameter is increased, a high-order mode is easily introduced, and thus the mode is unstable, when the mode field diameter is reduced, in order to compensate the problem of low absorption in the high-power amplification process, a longer gain fiber is needed, and this may induce a nonlinear effect.

The phenomenon is burnt to the optic fibre that present high power fiber laser appears in the use, the point of burning often appears in the pump light and pours into the position near the initial section of gain optic fibre into, this is because the pump light injects the end, arouse the population reversal of gain optic fibre, make this part optic fibre very easily generate heat, the change of temperature easily makes the refracting index of optic fibre change again, the thermal effect that makes the optic fibre of different positions produce changes differently, arouse that the optic fibre local temperature is too high or lead to the optic fibre stress distribution inhomogeneous, under this unstable state, the life and each item performance of laser also will greatly discount.

SUMMERY OF THE UTILITY MODEL

The utility model provides a reducing optic fibre and high power fiber laser for high power fiber laser aims at solving the conventional art, and the pump light incident end of optic fibre leads to the temperature rise because of power change, arouses optic fibre mode instability easily, causes the problem that optic fibre burns out.

Aiming at the problems in the prior art, the utility model provides a reducing optical fiber for a high-power optical fiber laser, which comprises an outer cladding layer, an inner cladding layer and a fiber core which are arranged in sequence along the inner and outer directions, wherein the diameter of the outer cladding layer is uniformly arranged;

the fiber core is provided with a pump light incidence section and a middle section, the pump light incidence section is used for incidence of pump light, and the diameter of the fiber core of the pump light incidence section is smaller than that of the fiber core of the middle section.

According to the variable diameter optical fiber for the high power optical fiber laser, the pump light incident section comprises an incident section and a gradual change section which are connected in sequence, and the gradual change section is arranged between the incident section and the middle section;

the fiber core diameters of the incident section are equal, and the fiber core diameters of the gradual change section are gradually increased from the incident section to the middle section.

According to the utility model provides a pair of reducing optic fibre for high power fiber laser, the fibre core have form in the both ends of fibre core on length direction the pump light incident section and be formed at two between the pump light incident section the interlude.

According to the utility model provides a pair of reducing optic fibre for high power fiber laser, the fibre core diameter of interlude equals.

According to the utility model provides a pair of high power is reducing optic fibre for fiber laser, numerical aperture a of reducing optic fibre for fiber laser on length direction satisfies following relation:

0.05≤a≤0.11。

according to the utility model provides a pair of reducing optic fibre for high power fiber laser, each the length of incident section is 0-3m, each the fibre core diameter of incident section is 10-30 mu m.

According to the utility model provides a pair of reducing optic fibre for high power fiber laser, each the length of gradual change section is 1-50 m.

According to the utility model provides a pair of reducing optic fibre for high power fiber laser, the fibre core diameter of interlude is 18-50 mu m.

According to the utility model provides a pair of high power is reducing optic fibre for fiber laser, the diameter of surrounding layer is 380-.

The utility model also provides a high power fiber laser, include as above arbitrary high power fiber laser is with reducing optic fibre.

The utility model provides a reducing optic fibre for high power fiber laser reduces the fibre core diameter of pump light incident section through the change, reduces the instability of the power of pump light incident section for light can realize even unanimous the enlargeing in optic fibre, avoids optic fibre because of the unstable condition of mode that the temperature arouses, reduces the probability that optic fibre burns out, effectively prolongs the life of optic fibre.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of a variable diameter optical fiber for a high power optical fiber laser provided by the present invention.

Reference numerals:

1: the reducing optical fiber is used for the high-power optical fiber laser; 2: an outer cladding; 3: an inner cladding;

4: a fiber core; 5: a pump incident section; 6: a middle section;

7: an incident section; 8: a transition section.

Detailed Description

To make the objects, technical solutions and advantages of the present invention clearer, the drawings of the present invention are combined to clearly and completely describe the technical solutions of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the embodiments of the present invention can be understood in specific cases by those skilled in the art.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

The utility model provides a following describes with fig. 1 that the utility model provides a reducing optic fibre 1 for high power fiber laser, because the utility model discloses a main invention point lies in reducing optic fibre 1 for high power fiber laser, therefore no longer gives unnecessary details to the relevant structure of high power fiber laser.

Aiming at the problems in the prior art, the utility model provides a reducing optical fiber 1 for a high-power optical fiber laser, which comprises an outer cladding layer 2, an inner cladding layer 3 and a fiber core 4 which are sequentially arranged along the inner and outer directions, wherein the diameter of the outer cladding layer 2 is uniformly arranged, namely the diameter of the optical fiber viewed from the outside in the length direction is the same; the fiber core 4 has a pump light incident section 5 and an intermediate section 6, the pump light incident section 5 is used for the incidence of pump light, and the fiber core diameter of the pump light incident section 5 is smaller than that of the intermediate section 6.

It should be noted that the core-to-core ratio of the double-clad (outer cladding and inner cladding) optical fiber in the conventional art is uniform, i.e., the diameter of the core 4 is uniformly arranged. However, the pump light power is not uniform in the double-clad fiber, and the power at the incident end of the pump light is generally high, which also results in the temperature of the double-clad fiber being high at the incident end of the pump light. The utility model provides a reducing optic fibre 1 for high power fiber laser compares through the core package that reduces pumping light incident section 5 for pumping light incident section 5's effective absorption area reduces, can effectively reduce 4 terminal surface departments of fibre core particle number reversal rate, avoids the unstable condition of mode that optic fibre arouses because of the temperature, reduces the probability that optic fibre burns out, effectively prolongs the life of optic fibre.

It should be noted that the diameter of the fiber core of the pump light incident section 5 may be uniformly set or may be set with variable diameter, and it is only necessary that the diameter of the fiber core is smaller than that of the fiber core of the middle section 6. In the technical solution provided by the present invention, the pump light incident section 5 comprises an incident section 7 and a gradual change section 8 which are connected in sequence, and the gradual change section 8 is arranged between the incident section 7 and the middle section 6; the core diameters of the incident section 7 are equal, and the core diameters of the graded section 8 are gradually increased from the incident section 7 to the middle section 6.

It should be noted that the core diameter of the incident section 7 is smaller than the core diameter of the intermediate section 6, and the core diameter of the transition section 8 gradually increases from the core diameter of the incident section 7 to the core diameter of the intermediate section 6, and such increase may be linear or non-linear, which is not limited by the present invention. So set up, the pumping light gets into from the relatively little incident section 7 of core package, and the effective absorption sectional area of incident section 7 is little, can effectively reduce terminal surface department population inversion rate, and light passes through one section core package and compares gradual change section 8 of gradual change afterwards, and transition to interlude 6 (the optic fibre that uses the core package to compare usually again), can balance the power change fluctuation of optic fibre in length direction, satisfies the pumping absorption value that the optic fibre needs to reach. It should be noted that, in the technical scheme provided by the utility model, the fiber core diameter of interlude 6 is for evenly setting up.

The double-cladding large-mode-field doped fiber adopted by the conventional high-power fiber laser is generally in a fixed core-cladding ratio, namely the sizes of a fiber core 4 and a cladding are consistent in the transmission direction and do not change, light enters from an inner cladding 3 with a large area, and when pump light is transmitted in the inner cladding 3, the pump light continuously passes through the fiber core 4 so as to be absorbed by doped ions in the fiber core 4, and the generated laser light is transmitted out of a waveguide of the fiber core 4. Compared with a unidirectional pumping optical fiber laser, the bidirectional pumping mode can be adopted to couple in higher pumping power so as to realize higher power output. Therefore in the technical scheme provided by the utility model, fibre core 4 has and is formed at the pump light incident section 5 at the both ends of fibre core 4 on length direction and forms interlude 6 between two pump light incident sections 5, so when satisfying above-mentioned implementation effect, can form the form of two-way pumping, realizes the output of optic fibre higher power.

Specifically, in the embodiment provided by the utility model, the numerical aperture a of the reducing optical fiber 1 for the high-power optical fiber laser in the length direction satisfies that a is more than or equal to 0.05 and less than or equal to 0.11; the length of each incident section 7 is 0-3m, and the diameter of the fiber core of each incident section 7 is 10-30 μm; the length of each transition section 8 is 1-50 m; the diameter of the core of the middle section 6 is 18-50 μm; the diameter of the outer cladding 2 is 380-800 μm.

The utility model optimizes the design of the fiber core 4, and effectively solves the variation range of the pump light power in the double-clad fiber on the fiber length compared with the double-clad ytterbium-doped fiber with fixed core cladding ratio used at present; the light can be uniformly and uniformly amplified in the optical fiber, the temperature rise of the pump light incident section 5 of the optical fiber caused by power change is effectively reduced, the mode instability condition of the optical fiber caused by temperature is avoided, the probability of burning the optical fiber is reduced, and the service life of the optical fiber is effectively prolonged.

Furthermore, the utility model provides a technical scheme can avoid when making high power fiber laser exceeding the condition of fiber end input power damage threshold value because of the pumping power is too high to take place, can effectively improve the power of fiber laser terminal surface pumping, when increasing the doping concentration of tombarthite doping optic fibre, reduce the possibility that optic fibre burns out, improve the damage threshold value of optic fibre, greatly increased high power fiber laser's output energy, enlarge fiber laser's application scene and scope, promote life.

The utility model also provides a high power fiber laser, including above-mentioned reducing optic fibre 1 for high power fiber laser, because the utility model discloses a main invention point lies in reducing optic fibre 1 for high power fiber laser, consequently no longer gives unnecessary details to the correlation structure of high power fiber laser.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims (10)

1. The variable diameter optical fiber for the high-power optical fiber laser is characterized by comprising an outer cladding layer, an inner cladding layer and a fiber core which are sequentially arranged along the inner direction and the outer direction, wherein the diameter of the outer cladding layer is uniformly arranged;

the fiber core is provided with a pump light incidence section and a middle section, the pump light incidence section is used for incidence of pump light, and the diameter of the fiber core of the pump light incidence section is smaller than that of the fiber core of the middle section.

2. The variable diameter optical fiber for the high power optical fiber laser as claimed in claim 1, wherein the pump light incident section comprises an incident section and a transition section connected in sequence, the transition section is disposed between the incident section and the middle section;

the fiber core diameters of the incident section are equal, and the fiber core diameters of the gradual change section are gradually increased from the incident section to the middle section.

3. The variable diameter optical fiber for a high power fiber laser according to claim 2, wherein the core has the pump-light incident sections formed at both ends of the core in a length direction and the intermediate section formed between the two pump-light incident sections.

4. The tapered fiber for a high power fiber laser as claimed in claim 3, wherein the cores of the intermediate section have the same diameter.

5. The tapered optical fiber for a high power fiber laser as claimed in claim 4, wherein the numerical aperture a of the tapered optical fiber for a high power fiber laser in the length direction satisfies the following relationship:

0.05≤a≤0.11。

6. the variable diameter optical fiber for high power fiber laser as claimed in claim 5, wherein the length of each incident segment is 0 to 3m, and the core diameter of each incident segment is 10 to 30 μm.

7. The tapered optical fiber for a high power fiber laser as claimed in claim 6, wherein the length of each of the tapered sections is 1 to 50 m.

8. The tapered optical fiber for a high power fiber laser as claimed in claim 7, wherein the core diameter of the intermediate section is 18 to 50 μm.

9. The tapered optical fiber as claimed in claim 8, wherein the outer cladding has a diameter of 380-800 μm.

10. A high power fiber laser comprising the variable diameter fiber for a high power fiber laser according to any one of claims 1 to 9.

Images