CN216927143U - Coaxial doped microstructure optical fiber - Google Patents

Abstract

The utility model discloses a coaxial doped microstructure optical fiber which sequentially comprises an optical fiber supporting part, an optical fiber cladding and a fiber core from outside to inside; the optical fiber cladding comprises outer cladding air holes which are arranged in a ring-shaped periodic manner and inner cladding air holes which are arranged in a polygonal lattice manner; the fiber core comprises a first rare earth ion-doped fiber core and a second rare earth ion-doped fiber core, and the first rare earth ion-doped fiber core annularly encloses the second rare earth ion-doped fiber core. The thulium-doped fiber core of the thulium-doped optical fiber is an annular internally-coated holmium-doped fiber core, the thulium ions and the holmium ions are independently distributed, so that the energy transfer up-conversion process can be greatly reduced, the intracavity loss is reduced, the utilization rate of pump light is improved, the air holes of the inner cladding are distributed in a hexagonal lattice manner, the air holes of the outer cladding are distributed in an annular periodic manner, the light guide mechanism of the microstructure optical fiber is met, and the low loss mechanism of the optical fiber can be ensured.

Description

Coaxial doped microstructure optical fiber

Technical Field

The utility model relates to the technical field of micro-structural optical fibers, in particular to a coaxial doped micro-structural optical fiber.

Background

In the past decades, fiber laser research has been directed mainly on how to increase output power, how to obtain multiple wavelength outputs, how to change output wavelengths, and the like. The output optical band of the 2-micron holmium-doped fiber laser is positioned in a human eye safety band (>1.7 microns) and an atmospheric window. In the field of biological medical treatment, the laser band has small damage to human tissue for surgical cutting hemostasis, has lower penetration depth and good medical accuracy to various soft and hard tissues, is often used for high-precision surgical cutting and medical diagnosis, and has prominent application prospect; in the communication field, 2-micrometer laser is positioned near an atmospheric window, so that the loss is small in long-distance laser communication; is also an ideal light source for generating 3-5 mu m mid-infrared laser output; in addition, the method has very important practical application value in the fields of laser radar, remote sensing technology, spectroscopy, photoelectric countermeasure and the like, thereby becoming an international research hotspot. However, the 1950nm semiconductor laser suitable for the 2 μm holmium-doped fiber laser is slow to develop, the output brightness is far lower than that of the multimode semiconductor laser suitable for the 1 μm fiber laser, sufficient pumping brightness is difficult to provide for the holmium-doped fiber laser, and the problem of lack of a high-power LD pumping source with proper wavelength and direct use causes low laser efficiency and limited power, so that the holmium-doped fiber laser usually adopts the same-band pumping technology or a thulium-holmium co-doped double-clad fiber as a gain medium at present. The thulium-doped laser is generally required to be pumped by the same-band pumping technology, the efficiency is lower and is only 43%, and the thermal load is severe when the laser runs at high power, which is also a main factor limiting the development and application of the laser; the thulium-holmium co-doped fiber laser is characterized in that a fiber core is doped with thulium elements and holmium elements at the same time, and through an energy transfer mechanism between thulium and holmium, holmium ions indirectly absorb pump light energy, but the limiting efficiency of the performance of the thulium-holmium co-doped fiber laser due to the fact that energy is transferred between the thulium ions and the holmium ions and converted is lower than that of a same-band pump fiber laser, the slope efficiency is only 34%, and the output power is low.

SUMMERY OF THE UTILITY MODEL

In view of this, in order to solve the problems of insufficient pump brightness, inappropriate wavelength, low slope efficiency, low output power and the like of the current 2 μm holmium-doped fiber laser, the utility model provides a coaxial doped microstructure fiber which effectively overcomes the structural defects of the thulium-holmium co-doped photonic crystal fiber, can realize targeted optimization of the performance of the fiber by changing the structural parameters of the fiber, and has a series of advantages of compact structure, large gain bandwidth, flexible working wavelength, high efficiency and the like.

The utility model solves the problems through the following technical means:

a coaxial doped microstructure optical fiber comprises an optical fiber supporting part, an optical fiber cladding and a fiber core from outside to inside in sequence;

the optical fiber cladding comprises outer cladding air holes which are arranged in a ring-shaped periodic manner and inner cladding air holes which are arranged in a polygonal lattice manner;

the fiber core comprises a first rare earth ion-doped fiber core and a second rare earth ion-doped fiber core, and the first rare earth ion-doped fiber core annularly encloses the second rare earth ion-doped fiber core.

Further, the first rare earth ion-doped fiber core is a thulium-doped fiber core, and the second rare earth ion-doped fiber core is a holmium-doped fiber core.

Further, the first rare earth ion-doped fiber core is a holmium-doped fiber core, and the second rare earth ion-doped fiber core is a thulium-doped fiber core.

Furthermore, the first rare-earth-ion-doped fiber core is an ytterbium-doped fiber core, a neodymium-doped fiber core, an erbium-doped fiber core or a praseodymium-doped fiber core, the second rare-earth-ion-doped fiber core is an ytterbium-doped fiber core, a neodymium-doped fiber core, an erbium-doped fiber core or a praseodymium-doped fiber core, and the first rare-earth-ion-doped fiber core and the second rare-earth-ion-doped fiber core are not the same rare-earth-ion-doped fiber core.

Further, the inner cladding air holes are arranged in a quadrilateral shape, a pentagonal shape, a hexagonal shape, a heptagonal shape, an octagonal shape, a nonagonal shape or a decagonal shape.

Furthermore, the inner cladding air holes are formed by arranging four, five, six or seven layers of air holes.

Further, the optical fiber support part is a quartz-based material, a silicate glass, a sulfide glass, or a fluoride glass.

Further, the core is a quartz-based material, a silicate glass, a sulfide glass, or a fluoride glass.

Compared with the prior art, the utility model has the beneficial effects that at least:

compared with the prior thulium-holmium co-doped microstructure optical fiber, the coaxial doped microstructure optical fiber has flexible and controllable special structure and optical performance, reduces non-radiation loss (such as up-conversion loss), and thulium ions absorb pump light to generate signal light with the wavelength of about 1950nm, so that the energy of thulium ions is transferred to holmium ions, LD direct pumping can be realized, the thermal load is smaller compared with the same band pumping technology, the holmium-doped fiber laser built by using the fiber can greatly reduce the complexity of the device, and because the thulium-doped fiber core part and the holmium-doped fiber part are independently distributed, the energy transmission up-conversion loss of thulium ions and holmium ions is greatly reduced, laser with the wavelength of about 2 mu m can be generated by cladding pumping, high-efficiency and high-power laser output is facilitated, and the optical fiber structure provides support for the application of the holmium-doped optical fiber in the aspects of communication, biomedical treatment and the like.

Drawings

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

FIG. 1 is a cross-sectional view of a five-layer inner cladding air hole coaxial doped microstructured optical fiber of the present invention;

FIG. 2 is a cross-sectional view of a four-layer inner cladding air hole coaxial doped microstructured optical fiber of the present invention;

description of the reference numerals:

1. an optical fiber supporting portion; 2. outer cladding air holes; 3. inner cladding air holes; 4. a first rare earth ion-doped fiber core; 5. a second rare earth ion doped core.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention belong to the protection scope of the present invention.

As shown in fig. 1, the present invention provides a coaxial doped microstructured optical fiber, which comprises, in order from outside to inside, an optical fiber supporting portion 1, optical fiber claddings 2 and 3, and fiber cores 4 and 5. The optical fiber cladding comprises outer cladding air holes 2 which are annularly and periodically arranged and inner cladding air holes 3 which are arranged in a hexagonal lattice manner; the fiber core comprises a first rare earth ion-doped fiber core 4 and a second rare earth ion-doped fiber core 5, and the first rare earth ion-doped fiber core 4 annularly encloses the second rare earth ion-doped fiber core 5.

In this embodiment, the first rare earth ion doped fiber core 4 is a thulium doped fiber core, the second rare earth ion doped fiber core 5 is a holmium doped fiber core, and the thulium doped fiber core is an annular holmium doped core internally wrapped.

In this embodiment, the optical fiber supporting portion 1, the first rare earth ion-doped fiber core 4, and the second rare earth ion-doped fiber core 5 are made of a quartz-based material, and the outer cladding air holes 2 and the inner cladding air holes 3 are made of air, but the inner cladding air holes 3 are not limited to air, and may be made of a material such as a germanium-doped glass rod to form a solid inner cladding, and the optical fiber supporting portion 1, the first rare earth ion-doped fiber core 4, and the second rare earth ion-doped fiber core 5 are not limited to a quartz-based material, and may be made of other materials such as silicate glass, sulfide glass, fluoride glass, and the like.

In this embodiment, the inner cladding air holes 3 are arranged in a hexagon, but the utility model is not limited to the arrangement in the hexagon, and the arrangement mode may be a quadrangle, a pentagon, a hexagon, a heptagon, an octagon, a nonagon or a decagon.

In this embodiment, the inner cladding air holes 3 are formed by arranging five air holes, but the present invention is not limited to five air holes, and may be four, six, or seven layers, etc., as shown in fig. 2, which are four air holes.

The coaxial doped microstructure optical fiber is mainly used for generating 2-micron high-power holmium laser. The existing thulium-holmium co-doped photonic crystal fiber has the problems of large loss, low slope efficiency, low output power and the like. The coaxial doped microstructure optical fiber mainly comprises a fiber core, inner cladding air holes and outer cladding air holes, wherein the fiber core comprises a holmium-doped fiber core and a thulium-doped fiber core, the thulium-doped fiber core is in a ring shape and internally contains the holmium-doped fiber core, the energy transfer up-conversion process of the thulium ions and the holmium ions can be greatly reduced due to the independent distribution of the thulium ions and the holmium ions, so that the loss in a cavity is reduced, the utilization rate of pump light is improved, the inner cladding air holes are in hexagonal lattice arrangement, the outer cladding air holes are in ring periodic arrangement, the light guide mechanism of the microstructure optical fiber is met, and the low loss mechanism of the optical fiber can be ensured.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the utility model, and these changes and modifications are all within the scope of the utility model. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims (8)

1. A coaxial doped microstructure optical fiber is characterized by comprising an optical fiber supporting part, an optical fiber cladding and a fiber core from outside to inside in sequence;

the optical fiber cladding comprises outer cladding air holes which are arranged in a ring-shaped periodic manner and inner cladding air holes which are arranged in a polygonal lattice manner;

the fiber core comprises a first rare earth ion-doped fiber core and a second rare earth ion-doped fiber core, and the first rare earth ion-doped fiber core annularly internally wraps the second rare earth ion-doped fiber core.

2. The coaxial doped microstructured fiber of claim 1, wherein the first rare earth-doped core is a thulium-doped core and the second rare earth-doped core is a holmium-doped core.

3. The coaxial doped microstructured fiber of claim 1, wherein the first rare earth-doped core is a holmium-doped core and the second rare earth-doped core is a thulium-doped core.

4. The coaxial doped microstructured fiber of claim 1, wherein the first rare-earth-ion-doped core is an ytterbium-doped core, a neodymium-doped core, an erbium-doped core, or a praseodymium-doped core, the second rare-earth-ion-doped core is an ytterbium-doped core, a neodymium-doped core, an erbium-doped core, or a praseodymium-doped core, and the first rare-earth-ion-doped core and the second rare-earth-ion-doped core are not the same rare-earth-ion-doped core.

5. The coaxial doped microstructured optical fiber of claim 1, wherein the inner cladding air holes are in a quadrilateral arrangement, a pentagonal arrangement, a hexagonal arrangement, a heptagonal arrangement, an octagonal arrangement, a nonagonal arrangement, or a decagonal arrangement.

6. The coaxial doped microstructured fiber of claim 1, wherein the inner cladding air holes are formed by four, five, six or seven air hole arrangements.

7. The coaxial doped microstructured fiber of claim 1, wherein the fiber support portion is a silica-based material, a silicate glass, a sulfide glass, or a fluoride glass.

8. The coaxial doped microstructured fiber of claim 1, wherein the core is a silica-based material, a silicate glass, a sulfide glass, or a fluoride glass.

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