CN104238014A - Parallel optical fiber cladding light filtering device - Google Patents

Abstract

The invention provides a parallel optical fiber cladding light filtering device which comprises a target filtering optical fiber. Multiple parallel optical fibers are parallel to the target filtering optical fiber and make tight contact with the target filtering optical fiber. According to the parallel optical fiber cladding light filtering device, the optical fibers are large in flexibility, short in filtering length and easy to control.

Description

Parallel optical fiber cladding light filtering device

technical field

The invention relates to the field of fiber laser technology, in particular to a parallel optical fiber cladding light filtering device.

Background technique

With the development of fiber laser technology, the output capacity of fiber is continuously improved. In some specific fields, it is necessary to release the transmission power in the fiber cladding. For example, pump filtering is performed at the gain tail, and in order to improve the brightness of the output, the power transmitted in the cladding is filtered to obtain a pure core output.

At present, there are many technologies and equipment that can provide cladding power filtering, but for the traditional filtering process, other materials and equipment are introduced into the cladding of the optical fiber, or the cladding of the optical fiber is directly processed by a taper. At present, the power that these methods can withstand is on the order of hundreds of watts. At the same time, the prominent safety problem is that when the filtering power exceeds the safety limit of the filter, it will cause the filtering part to fail. The failures usually caused are: the refractive index matching self-absorption leads to overheating deformation or even burning of the material; optical phenomena such as self-focusing in the matching layer; the cracking and bursting of the fiber cladding due to stress; Excessive core temperature causes the core to assume a molten state. All of these have had a great impact on the original fiber laser system. Usually, when the cladding filter used in the original fiber laser system fails and is damaged, the original laser system cannot work normally.

At the same time, the traditional cladding filtering process usually removes the cladding light within a few centimeters of fiber length, and it is difficult to control the cladding light in the original fiber to be slowly filtered out at the current technical level. For example, if the cladding of the original optical fiber is coated with a refractive index matching layer, its ability to filter out light with a specific numerical aperture is usually about 3 dB/cm. The concept of slowness mentioned above is to control the filtering ability in the order of 1dB/m.

Contents of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

For this reason, the object of the present invention is to propose a kind of parallel optical fiber cladding light filtering device with large flexibility, short filtering length and easy control.

In order to achieve the above object, a parallel optical fiber cladding light filtering device according to an embodiment of the present invention includes: a target filter fiber; a plurality of parallel fibers, the multiple parallel fibers are parallel to the target filter fiber and mutually Close contact setting.

A parallel optical fiber cladding light filtering device according to an embodiment of the present invention adopts the method that the parallel optical fiber is in close contact with the target filtering fiber, so that the cladding light in the target filtering fiber is evenly and slowly diverged into the environment , the optical fiber is flexible and the filtering length is short, which is convenient for control and safe filtering.

In some examples, the process of filtering the cladding light by the parallel optical fiber cladding light filtering device is: the cladding light gradually enters the cladding of the multiple parallel optical fibers from the cladding of the target filtering optical fiber layer; performing cladding filtering treatment on the multiple parallel optical fibers so that the cladding light in the multiple parallel optical fibers is dissipated into the environment.

In some examples, the refractive index of the cladding of the plurality of parallel optical fibers is greater than or equal to the refractive index of the cladding of the target filter fiber.

In some examples, the target filtering optical fiber is arranged in close contact with the whole or partial segments of the plurality of parallel optical fibers.

In some examples, the plurality of parallel optical fibers are in close contact with the target filtering optical fiber through fusion or crimping.

In some examples, the plurality of parallel optical fibers are parallel optical fibers with a core, without a core, or with a core within a section in the middle of the cladding.

Additional aspects and advantages of the invention 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 invention.

Description of drawings

Fig. 1 is a structural block diagram of a parallel optical fiber cladding light filtering device according to an embodiment of the present invention;

Fig. 2 is a schematic structural view of a parallel optical fiber cladding light filtering device according to an embodiment of the present invention;

Fig. 3 is a schematic structural view of a parallel optical fiber cladding light filtering device according to another embodiment of the present invention;

Fig. 4 is a schematic structural view of a parallel optical fiber cladding light filtering device according to another embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

Fig. 1 is a structural block diagram of a parallel optical fiber cladding light filtering device according to an embodiment of the present invention. As shown in FIG. 1 , the optical fiber of the embodiment of the present invention includes: a target filtering optical fiber 100 and multiple parallel optical fibers 200 . Wherein, a plurality of parallel optical fibers 200 are arranged in parallel with the target filtering optical fiber 100 and in close contact with each other.

Specifically, in one embodiment of the present invention, the entire or partial segments of the target filtering optical fiber 100 and the multiple parallel optical fibers 200 are arranged in close contact. The multiple parallel optical fibers 200 are in close contact with the target filtering optical fiber 100 by means of fusion or pressing.

In one embodiment of the present invention, the plurality of parallel optical fibers 200 are parallel optical fibers with a core, without a core, or with a core in a segment in the middle of the cladding.

Further, the parallel optical fiber cladding light filtering device of the embodiment of the present invention also includes: a cladding filter 300, which is used to filter the cladding in a plurality of parallel optical fibers 200, so as to filter out the target filter Cladding light in fiber 100. This process prevents the optical fiber in the fiber laser system from directly filtering the cladding light to the environment, thereby avoiding the impact on the fiber laser system caused by damage when the traditional process reaches the power limit.

In one embodiment of the present invention, the cladding filter 300 performs cladding filtering on the entire or part of the multiple parallel optical fibers 200 . In this way, the cladding light can be gradually filtered out over a long fiber length, that is, the filter pressure of the target filter fiber can be distributed to the entire parallel fiber length.

In an embodiment of the present invention, the refractive index of the cladding of the plurality of parallel optical fibers 200 is greater than or equal to the refractive index of the cladding of the target filtering fiber 100 .

In one embodiment of the present invention, the process of filtering cladding light by the parallel optical fiber cladding light filtering device is: cladding light gradually enters 200 of multiple parallel optical fibers from the cladding of the target filter optical fiber 100 layers. The cladding light filter 300 is used to perform cladding filtering treatment on the multiple parallel optical fibers 200 so that the cladding light in the multiple parallel optical fibers 200 is dissipated into the environment.

Taking a target filtering optical fiber and a parallel optical fiber as examples below, the cladding light filtering working process of the optical fiber in the embodiment of the present invention is described as follows:

When a target filtering fiber with a similar refractive index and a parallel fiber are in parallel contact, the contact here refers to the tight contact state of external force clamping or even welding. The light transmitted in the cladding of the two fibers will enter each other's cladding and propagate. After a certain length, the cladding light transmitted in the two optical fibers is finally the same, and is half of the sum of the cladding light propagating in the original two optical fibers. At the same time, filtering is performed on the parallel optical fiber. In this way, after a certain length, the cladding light in the target filtering fiber continuously enters the parallel fiber, and is continuously filtered from the parallel fiber to the environment, thereby realizing the cladding light filtering of the target filtering fiber. In this way, the above-mentioned filtering process is independent from the original optical fiber. At the same time, this process is a very slow process because the cladding light in the target filtering fiber enters the parallel fiber, which ensures that the overall filtering is also a very slow process.

For example, in the optical fiber shown in FIG. 2 , 1 is a parallel optical fiber that has been processed to a certain extent, and the optical fiber uses the same material as the cladding 22 of the target filtering optical fiber 21 . After the parallel optical fiber has been processed, the coating layer of the parallel optical fiber is stripped at positions 12 and 13, so that the cladding layer of this optical fiber is exposed in this section area. A traditional cladding filter is arranged on the two exposed fiber claddings by means of refractive index matching.

Wherein, the unprocessed optical fiber length is not shown proportionally in the figure, and in an actual system, the unprocessed parallel optical fiber length is much longer than the treated part that needs to be equipped with a cladding filter. This is to ensure that the cladding light transmitted in the target filter fiber can have enough length to enter the parallel fiber. The cladding material of the parallel optical fiber in this embodiment is the same as that of the target filtering optical fiber, which is a silica rod without a core.

As shown in FIG. 3 , 21 is the target filter fiber, 22 is the cladding of the target filter fiber, and 3 is the parallel fiber contacted with 2 using certain technical means. The technical means mentioned here is to closely bond the two optical fibers after stripping off the coating layer of the target filtering optical fiber and the parallel optical fiber. At the same time, the oxyhydrogen flame is used to heat briefly along the length of the fiber, so that it can be closely combined with the parallel fiber without destroying the structure and optical properties of the target filtering fiber. 24 and 25 are all cladding filters using traditional technology. 26 and 27 are close contact sections between the parallel optical fiber and the target filtering optical fiber. The direction of the arrow in the figure is the direction of cladding light transmission in the optical fiber system. 28 shows the recoating layer formed by the recoating process of the target filter fiber and the contact section of the parallel fiber. Play the role of clamping and fixing the optical fiber.

When the cladding light propagates in the target filter fiber, the cladding light is continuously transferred to the parallel fiber through the part tightly combined with the parallel fiber. After a certain length, the total amount of cladding light transmitted in the parallel fiber reaches half of the original cladding light content of the target fiber. Then through a filtering device, this part of the light energy is filtered into the environment. This process is repeated continuously, so that the cladding light content transmitted in the target filter fiber gradually approaches zero.

In another embodiment of the present invention, as shown in FIG. 3 , a parallel optical fiber 31 that has been processed to a certain extent, the entire section of optical fiber has been treated with cladding and roughening, so that the optical fiber in this optical fiber The cladding light transmitted upward can continuously diverge into the environment. The material used for the cladding of this optical fiber in this embodiment is consistent with the cladding material of the target filtering optical fiber, which is a quartz rod without a core. 32 is the target filtering fiber, 33 is the cladding of the target filtering fiber, and 31 is in close contact with the target filtering fiber 32 over a length of the fiber.

When the cladding light propagates in the target filter fiber, the cladding light is continuously transferred to the parallel fiber through the part tightly combined with the parallel fiber. At the same time, the cladding light in the parallel optical fiber continuously diverges into the environment due to the roughening of the cladding surface of the fiber. After a certain length, the cladding light content of the parallel optical fiber's cladding target filter fiber approaches to zero at the same time.

According to the parallel optical fiber cladding light filtering device according to the embodiment of the present invention, the parallel optical fiber is closely contacted with the target filtering optical fiber, so that the cladding light in the target filtering optical fiber is evenly and slowly diverged into the environment. The optical fiber is flexible and the filtering length is short, which is convenient for control and safe filtering.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (7)

1. a parallel optical fibre cladding light filtering device, is characterized in that, comprising:

Target filtering optical fiber;

Many parallel optical fibres, described many parallel optical fibres and described target filtering optical fiber walk abreast and close contact is arranged each other.

2. parallel optical fibre cladding light filtering device according to claim 1, is characterized in that, the process of described parallel optical fibre cladding light filtering device filtering cladding light is:

Described cladding light little by little enters the covering of described many parallel optical fibres by the covering of described target filtering optical fiber;

Carrying out covering filtering process to described many parallel optical fibres makes the cladding light in described many parallel optical fibres be dissipated in environment.

3. parallel optical fibre cladding light filtering device according to claim 1, is characterized in that, the refractive index of the covering of described many parallel optical fibres is more than or equal to the refractive index of the covering of described target filtering optical fiber.

4. parallel optical fibre cladding light filtering device according to claim 1, is characterized in that, whole or the setting of segment section close contact of described target filtering optical fiber and described many parallel optical fibres.

5. parallel optical fibre cladding light filtering device according to claim 1, is characterized in that, described covering stripper carries out covering filtering to whole of many parallel optical fibres described in every root or part.

6. parallel optical fibre cladding light filtering device according to claim 1, is characterized in that, by welding or press attached mode close contact between described many parallel optical fibres and described target filtering optical fiber.

7. the parallel optical fibre cladding light filtering device according to any one of claim 1-6, is characterized in that, described many parallel optical fibres are have fibre core, do not have fibre core or in covering middle section, have the parallel optical fibre of fibre core.