CN103135166B - Optical fiber capable of improving energy concentration inside optical fiber - Google Patents

Abstract

The invention relates to the technical field of waveguide media, in particular to an optical fiber capable of improving energy concentration in the optical fiber. The optical fiber includes a first fiber body and a second fiber body, the first fiber body includes a first cladding and a first circular fiber core; the first cladding is wrapped on the outer surface of the circular fiber core; the second fiber body includes a first Two cladding, second circular core and multi-core fiber unit; the second circular core is wrapped on the outer surface of the multi-core fiber unit; the first cladding is wrapped on the outer surface of the second circular core; multi-core The refractive index of the fiber unit is greater than the refractive index of the second circular fiber core. In the optical fiber provided by the present invention, a new layer of waveguide is formed by setting a multi-core fiber unit with a higher refractive index and the original fiber core, so that part of the light beam with a smaller divergence angle is trapped in the new waveguide, so that the energy concentration will increase. In turn, the beam quality is improved, and the fiber transmission distance and coupling efficiency are increased.

Description

An optical fiber capable of increasing energy concentration in the optical fiber

technical field

The invention relates to the technical field of waveguide media, in particular to an optical fiber capable of improving energy concentration in the optical fiber.

Background technique

A common optical fiber is composed of two parts, the core and the cladding. The cladding confines the light energy within the fiber core, where the light energy is then transmitted. In applications such as transmitting laser beam energy, the energy concentration (focusability) of the actual laser beam in the fiber core is an important basis for objectively measuring the beam quality. In the process of optical fiber transmission coupling, the energy concentration will affect the transmission coupling efficiency, which will have a serious impact on practical applications. Therefore, improving the energy concentration is of great significance for increasing the optical fiber transmission distance, increasing the beam quality and coupling efficiency.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is: how to provide an optical fiber with simple structure and high energy concentration.

(2) Technical solutions

In order to solve the above problems, the present invention provides an optical fiber capable of improving energy concentration in the optical fiber, comprising a first optical fiber main body and a second optical fiber main body, the first optical fiber main body includes a first cladding and a first circular core ; The first cladding is wrapped on the outer surface of the circular fiber core;

The second optical fiber body includes a second cladding, a second circular fiber core and a multi-core fiber unit; the second circular fiber core is wrapped on the outer surface of the multi-core fiber unit; the first cladding Wrapped on the outer surface of the second circular fiber core;

The refractive index of the multi-core optical fiber unit is greater than the refractive index of the second circular fiber core.

Further, the diameter of the first circular fiber core is the same as that of the second circular fiber core.

Further, the thickness of the first cladding layer is the same as that of the second cladding layer.

Further, the cross-section of the multi-core optical fiber unit is a center-symmetrical shape.

Further, the axis of symmetry of the multi-core fiber unit is parallel to the Z axis.

Further, five sub-cores are included, the five sub-cores are arranged in a "ten" shape, and the symmetry axis of the middle sub-core among the five sub-cores coincides with the Z axis.

Further, the five sub-cores have the same radius.

(3) Beneficial effects

In the optical fiber provided by the present invention, a layer of new waveguide is formed by setting a multi-core fiber unit with a higher refractive index and the original fiber core, so that part of the light beam with a smaller divergence angle is trapped in the new waveguide, so that the energy concentration will increase. In turn, the beam quality is improved, and the fiber transmission distance and coupling efficiency are increased.

Description of drawings

Fig. 1(a) is a schematic longitudinal view of the first optical fiber body of the present invention;

Figure 1(b) is a schematic cross-sectional view of the first optical fiber body of the present invention;

Figure 1(c) is a cross-sectional refractive index distribution diagram of the first optical fiber body of the present invention;

Fig. 2(a) is a longitudinal schematic diagram of the second ray body of the present invention;

Figure 2(b) is a schematic cross-sectional view of the first optical fiber body of the present invention;

Fig. 2(c) is a distribution diagram of the refractive index of the main body section of the first optical fiber of the present invention;

Fig. 3 is a longitudinal schematic diagram of the overall structure of the optical fiber of the present invention;

Figures 4(a) and 4(b) are the energy distribution diagram after coupling common optical fibers of the same size and the energy distribution diagram after coupling the present invention in Embodiment 1 of the present invention;

Figures 5(a) and 5(b) are respectively the energy distribution diagram after coupling common optical fibers of the same size and the energy distribution diagram after coupling the present invention in Embodiment 2 of the present invention;

Figures 6(a) and 6(b) are respectively the energy distribution diagram after coupling common optical fibers of the same size and the energy distribution diagram after coupling the present invention in Embodiment 3 of the present invention.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

As shown in FIG. 3 , the optical fiber capable of improving energy concentration in the optical fiber provided by the embodiment of the present invention includes: a first optical fiber body and a second optical fiber body.

Specifically, referring to FIG. 1(a) to FIG. 1(c), the first fiber body in this embodiment includes a first cladding 101 and a first circular core 102; the first cladding 101 is wrapped around the first The outer surface of a circular core 102.

Referring to Fig. 2(a) to Fig. 2(c), the second optical fiber body in this embodiment includes a second cladding 201, a second circular fiber core 202 and a multi-core fiber unit 203; the second circular fiber The core 202 is wrapped on the outer surface of the multi-core fiber unit 203 ; the second cladding 201 is wrapped on the outer surface of the second circular fiber core 202 .

Wherein, the diameter of the first circular core 102 is set to be the same as that of the second circular core 202 , and the thickness of the first cladding 101 is the same as that of the second cladding 201 .

Wherein, the refractive index of the first circular fiber core 102 and the refractive index of the second circular fiber core 202 may be the same or different, which may be determined according to actual requirements. Compared with the refractive index of the second cladding layer 201, the refractive index of the first cladding layer 101 may be the same or different, which may be determined according to actual requirements.

Referring to Figure 2(c), the cross section of the multi-core fiber unit 203 is a centrally symmetrical shape, and the axis of symmetry of the multi-core fiber unit 203 is parallel to the Z axis; the refractive index of the multi-core fiber unit 203 is greater than that of the second circular fiber core 202 refractive index. In this embodiment, the multi-core optical fiber unit 203 includes but is not limited to five sub-cores, which may be determined according to actual requirements.

After the light passes through the optical fiber provided by the invention, the multi-core fiber unit with higher refractive index and the original fiber core form a new layer of waveguide, so that some light beams with smaller divergence angles are trapped in the new waveguide, so that the energy concentration will increase. , thereby improving the beam quality, increasing the fiber transmission distance and coupling efficiency.

Energy concentration can increase, and the present invention will be further described below with specific embodiment:

Embodiment one

Light with a wavelength of 1064nm is coupled into the optical fiber: the length of the first fiber body in the fiber is 0.5m, and the numerical aperture is NA=0.22; the length of the second fiber body is 2cm, the second cladding 201 and the second circular core 202 Between the numerical aperture NA=0.22, the numerical aperture NA=0.1 between the multi-core fiber unit 203 and the second circular fiber core 202, the diameter of the second circular fiber core is 200um, the multi-core fiber unit 203 specifically includes five The five sub-cores are arranged in a cross shape, the axis of symmetry of the middle core coincides with the Z-axis, the radius of each sub-core is the same, and when the radius is 15um, the energy concentration is changed from the original The 20.812% increases to 26.744%, refer to Figure 4(a) and 4(b).

Embodiment two

Light with a wavelength of 1064nm is coupled into the fiber, the length of the first fiber body in the fiber is 0.5m, and the numerical aperture is NA=0.22; the length of the second fiber body is 0.5m, and the distance between the second cladding and the second circular core is The numerical aperture between NA=0.22, the numerical aperture NA=0.1 between the multi-core fiber unit 203 and the second circular fiber core, the diameter of the second circular fiber core is 200um, the multi-core fiber unit 203 specifically includes five sub-fibers core, the five sub-cores are arranged in a cross shape, the symmetry axis of the middle core coincides with the Z axis, and the radius of the five cores is the same, in the case of 15um, the energy concentration increases from the original 14.243% to 16.188%. Refer to Figures 5(a) and 5(b).

Embodiment three

Light with a wavelength of 1064nm is coupled into the fiber, the length of the first fiber body in the fiber is 0.5m, and the numerical aperture is NA=0.22; the length of the second fiber body is 0.5m, and the distance between the second cladding and the second circular core is Between the numerical aperture NA=0.22, the numerical aperture NA=0.1 between the multi-core fiber unit 203 and the second circular fiber core 202, the diameter of the second circular fiber core 202 is 400um, the multi-core fiber unit 203 includes five sub-cores Fiber core, the five sub-cores are arranged in a cross shape, the symmetry axis of the middle core coincides with the Z axis, and the radius of the five cores is the same, and the energy concentration increases from the original 28.024% to 28.732% when the radius is 25um , refer to Figures 6(a) and 6(b).

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (6)

1. the optical fiber that can improve optical fiber self-energy concentration degree, it is characterized in that, described optical fiber comprises the first fiber body and the second fiber body, and described the first fiber body is sequentially docked with described the second fiber body, and described the first fiber body comprises the first covering and the first circular core; Described the first covering is wrapped in the outside surface of described circular core;

Described the second fiber body comprises the second covering, the second circular core and multi-core fiber unit; Described the second circular core is wrapped in the outside surface of described multi-core fiber unit; Described the first covering is wrapped in the outside surface of described the second circular core; The refractive index of described multi-core fiber unit is greater than the refractive index of the second circular core, and the diameter of described the first circular core is identical respectively with diameter and the refractive index of the second circular core.

2. optical fiber according to claim 1, is characterized in that, the thickness of described the first covering is identical with the thickness of the second covering.

3. optical fiber according to claim 1, is characterized in that, symmetric shape centered by the section of described multi-core fiber unit.

4. optical fiber according to claim 3, is characterized in that, the axis of symmetry of described multi-core fiber unit is parallel with Z axis.

5. optical fiber according to claim 4, is characterized in that, comprises that described multi-core fiber unit comprises five sub-fibre cores, and described five sub-fibre cores are arranged with " ten " font, and the axis of symmetry of the dynatron fibre core in described five sub-fibre cores overlaps with Z axis.

6. optical fiber according to claim 5, is characterized in that, the radius of described five sub-fibre cores is identical.