CN116014544A - Mixed pump laser structure based on GT-WAVE structure - Google Patents

Abstract

The invention belongs to the technical field of optical fibers, and discloses a mixed pump laser structure based on a GT-WAVE structure, which comprises a sleeve, wherein the sleeve is internally provided with: a first core, the first core incorporating ytterbium element; an inner cladding layer which is coated outside the first fiber core; and a plurality of pump fibers closely surrounding the outer circumference of the inner cladding, wherein the axes of the first core, the inner cladding and each of the pump fibers are parallel to each other. The beneficial effects are that: the GT-wave structure reduces the heat quantity of the doped ion fiber core, the same-band pumping technology reduces the heat quantity of the doped ion first fiber core along the radial direction, and the combination of the two structures reduces the heat quantity of the doped ion first fiber core along the radial direction and the axial direction to the greatest extent.

Description

Mixed pump laser structure based on GT-WAVE structure

Technical Field

The invention relates to the technical field of optical fibers, in particular to a mixed pump laser structure based on a GT-WAVE structure.

Background

Under the push of urgent demands in the industrial and national defense application fields, the power boosting technology of the high-power fiber laser is attracting attention. At present, the further improvement of the power of the single-fiber optical fiber laser is mainly limited by the bottlenecks such as brightness of pumping light, nonlinear effect, unstable mode and the like. In recent years, researchers have proposed various ways to break through the above power boost limitations. The pump gain integrated composite function laser fiber (GT-wave fiber) comprises a rare earth ion doped fiber core and a plurality of pump fibers, realizes long-range side coupling based on evanescent wave coupling effect, and has outstanding performance in aspects of thermal management and nonlinear effect inhibition. The same band pumping technology generates laser with higher brightness through semiconductor laser pumping, and then the laser is used for pumping continuously to generate laser with higher brightness, so that the limitation of the brightness of pumping light is broken through, meanwhile, the thermal load of the gain fiber is relieved due to the smaller quantum loss in the secondary pumping process, and the mode instability threshold of the laser is improved. The 1018nm laser secondary pumping obtained by 976nm pumping is adopted by the IPG to obtain 1064nm laser, so that the Wanwave-level high-power output is realized. But ytterbium ions have low absorption efficiency on 1018nm pump light, so that the long gain fiber length is unfavorable for suppressing stimulated brillouin scattering. On the other hand, the cascade pumping system has more complicated structure and more devices due to the addition of the independent amplifying stage.

Disclosure of Invention

The invention aims to provide a mixed pump laser structure based on a GT-WAVE structure so as to solve the problem of contradiction between designs of optical fiber sizes on two limiting factors.

To achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a mixed pump laser structure based on GT-WAVE structure, includes the sleeve pipe, be equipped with in the sleeve pipe:

a first core, the first core incorporating ytterbium element;

an inner cladding layer which is coated outside the first fiber core; and

and the pump fibers tightly surround the periphery of the inner cladding, wherein the axes of the first fiber core, the inner cladding and each pump fiber are parallel to each other.

In some alternative embodiments, the cross section of the inner cladding is configured as a regular polygon, and each side of the regular polygon is correspondingly provided with one pump optical fiber.

In some alternative embodiments, the number of sides n of the polygon ranges from 2 < n < 10.

In some alternative embodiments, n=8.

In some alternative embodiments, the inner cladding is inscribed with high reflection gratings at both axial ends.

In some alternative embodiments, the high reflection gratings on both sides of the inner cladding are 1018nm in size.

In some alternative embodiments, a second core parallel to the first core is further disposed within the inner cladding, the second core being configured as an undoped core.

In some alternative embodiments, the diameter of the second core is greater than the diameter of the first core.

In some alternative embodiments, the diameter of the second core is 3-5 times the diameter of the first core.

The invention has the beneficial effects that:

the GT-wave structure reduces the heat quantity of the doped ion fiber core, the same-band pumping technology reduces the heat quantity of the doped ion first fiber core along the radial direction, and the combination of the two structures reduces the heat quantity of the doped ion first fiber core along the radial direction and the axial direction to the greatest extent.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a first view angle of a hybrid pump laser structure based on a GT-WAVE structure according to the first embodiment;

FIG. 2 is a schematic diagram of a second view angle of a hybrid pump laser structure based on a GT-WAVE structure according to the first embodiment;

fig. 3 is a schematic diagram of a first view angle of a hybrid pump laser structure based on a GT-WAVE structure according to a second embodiment.

In the figure:

1-a sleeve; 2-a first core; 3-inner cladding; 31-high reflection grating; 4-pumping the optical fiber; 5-a second core.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

Embodiment one:

the embodiment provides a hybrid pump laser structure based on a GT-WAVE structure, and fig. 1 is a schematic structural diagram of a laser structure according to the first embodiment.

As shown in fig. 1, the hybrid pump laser structure based on the GT-WAVE structure comprises a ferrule 1, a first core 2, an inner cladding 3 and a pump fiber 4.

The first fiber core 2 is doped with ytterbium, the inner cladding 3 is coated outside the first fiber core 2, and the plurality of pump fibers 4 tightly surround the outer periphery of the inner cladding 3, wherein the axes of the first fiber core 2, the inner cladding 3 and each pump fiber 4 are parallel to each other.

It should be noted that, the ytterbium element doped in the first fiber core 2 refers to that ytterbium element is doped in the pure quartz glass fiber, so as to facilitate the conversion of the passive transmission fiber into the active fiber with amplifying capability.

The Yb3+ ion doped laser material has the advantages that:

1. the Yb3+ ion absorption band is in the wavelength range of 800nm-1100nm, can be effectively coupled with ZnlnAs semiconductor pumping source, and at the same time, the absorption band is wider, the absorption section change in the short wavelength section (less than 970 nm) is slower, which is easy to influence on the output wavelength by the environmental temperature, and the semiconductor laser pumping with narrow emission band is very beneficial, namely, the semiconductor laser output with matched wavelength is obtained without strictly controlling the temperature.

2. Yb3+ energy level has a simple structure and contains only two multiple states, so that there is no excited state absorption at both the pump wavelength and the signal wavelength. The light conversion efficiency is very high, and the large energy level interval also eliminates the phenomena of non-radiative relaxation and concentration quenching.

3. The pumping wavelength is very close to the laser output wavelength, and the quantum efficiency is high (up to 90%).

4. The thermal load in the material is low (less than 11%). Only one third of the Nd3+ doped homogeneous material.

5. The fluorescence lifetime is long, which is three times more than that of the Nd < 3+ > doped homogeneous material, and the energy storage is facilitated. These advantages of Yb3+ doped laser materials are of profound significance for the development of laser technology. In the conventional solid-state laser, the gain medium is in a long rod shape, and the heat flow direction is perpendicular to the laser beam direction, which is liable to cause thermal lens effect and temperature rise, resulting in deterioration of laser performance and reduction of laser efficiency. In particular, the thermal effect is more pronounced in three-level laser systems due to the high pumping power required. Because Yb3+ doping concentration can be very high, thermal load in the material is low, and even under high pumping power density, temperature change in the material is very small, so that thermal stress and thermal distortion in the gain medium are greatly reduced.

The GT-wave structure reduces the heat quantity of the doped ion fiber core, the same-band pumping technology reduces the heat quantity of the doped ion first fiber core along the radial direction, and the combination of the two structures reduces the heat quantity of the doped ion first fiber core along the radial direction and the axial direction to the greatest extent.

Further, the cross section of the inner cladding 3 is configured as a regular polygon, and each side of the regular polygon is correspondingly provided with one pump optical fiber 4. Avoiding absorption weakening caused by spiral rotation of 1018nm pump light in the propagation process.

The cross section of the inner cladding 3 is arranged to be regular polygon, and each edge is correspondingly provided with a pumping optical fiber 4, so that light rays can be transmitted more uniformly.

In this embodiment, the cross section of the inner cladding 3 is set to be a regular octagon. Accordingly, eight pump fibers 4 are provided.

Further, the inner cladding 3 is inscribed with high reflective gratings 31 at both axial ends. The high reflection grating 31 on the inner cladding layer 3 forms a resonant cavity, thereby realizing long-range side-coupled pumping.

In this embodiment, the high reflection gratings 31 on both sides of the inner cladding layer 3 are 1018nm in size. The high brightness 1018nm laser and the incompletely absorbed semiconductor pump laser are repeatedly transmitted through the fiber core 2, and 1064nm seed light injected by the fiber core 2 is amplified in power.

Embodiment two:

fig. 2 is a schematic diagram of a hybrid pump laser structure based on a GT-WAVE structure according to a second embodiment, as shown in fig. 2, where a second core 5 parallel to the first core 2 is further disposed in the inner cladding 3, and the second core 5 is configured as an undoped core.

The second core 5 collects energy generated in the first core 2, limits thermal effects in the first core 2, and reduces the size of the first core 2 to a certain extent to achieve mode instability suppression.

Further, the diameter of the second core 5 is larger than the diameter of the first core 2. The nonlinear effects of stimulated brillouin scattering, stimulated raman scattering, etc. can be ameliorated by increasing the diameter of the second core 5.

Further, the diameter of the second core 5 is 3-5 times the diameter of the first core 2.

The second embodiment further suppresses the mode instability effect and the nonlinear effect based on the first embodiment, and realizes the laser output at a higher power level.

It is to be understood that the above examples of the present invention are provided for clarity of illustration only and are not limiting of the embodiments of the present invention. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the invention. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.

Claims (9)

1. The utility model provides a mixed pump laser structure based on GT-WAVE structure, includes sleeve pipe (1), its characterized in that, be equipped with in sleeve pipe (1):

a first fiber core (2), the first fiber core (2) being doped with ytterbium element;

an inner cladding (3) which is coated outside the first fiber core (2); and

-a pump fiber (4), a plurality of said pump fibers (4) being tightly surrounding the outer circumference of said inner cladding (3), wherein the axes of said first core (2), said inner cladding (3) and each of said pump fibers (4) are parallel to each other.

2. The hybrid pump laser structure based on GT-WAVE structure according to claim 1, characterized in that the cross section of the inner cladding (3) is arranged as a regular polygon, each side of the regular polygon being provided with one of the pump fibers (4) in correspondence.

3. The GT-WAVE structure based hybrid pump laser structure according to claim 2 wherein the number of sides n of the polygon ranges from 2 < n < 10.

4. A GT-WAVE structure based hybrid pump laser structure according to claim 3 wherein n=8.

5. The GT-WAVE structure based hybrid pump laser structure according to claim 1, characterized in that the inner cladding (3) is inscribed with high reflective gratings (31) at both axial ends.

6. The GT-WAVE structure based hybrid pump laser structure according to claim 5, characterized in that the high reflection gratings (31) on both sides of the inner cladding (3) are of dimensions 1018nm.

7. The GT-WAVE structure based hybrid pump laser structure according to any of claims 1 to 6, characterized in that a second core (5) parallel to the first core (2) is further provided in the inner cladding (3), the second core (5) being arranged as an undoped core.

8. The GT-WAVE structure based hybrid pump laser structure according to claim 7, characterized in that the diameter of the second core (5) is larger than the diameter of the first core (2).

9. A GT-WAVE structure based hybrid pump laser structure according to claim 8 wherein the diameter of the second core (5) is 3-5 times the diameter of the first core (2).

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