阅读说明：本技术 一种大模场光子晶体光纤的低损耗、高强度熔接方法 (A kind of low-loss of large mode area pcf, high-intensitive welding process ) 是由 肖力敏 于若玮 王草源 于 2019-07-27 设计创作，主要内容包括：本发明属于全光纤技术领域,具体为一种大模场光子晶体光纤的低损耗、高强度熔接方法。本发明方法包括：获取两种待熔接光纤,第一待熔接光纤的模场直径大于第二待熔接光纤的模场直径,第一待熔接光纤的包层直径大于第二待熔接光纤的包层直径；对第二待熔接光纤进行反向拉锥和热致扩芯混合处理,使第二待熔接光纤的模场直径和包层直径均在第一待熔接光纤的匹配范围内；将第一待熔接光纤与混合技术处理后的第二待熔接光纤进行熔接。本发明提出的熔接方法,熔接损耗超低、熔接点机械强度高,增加了大模场光子晶体光纤在实际应用过程中的可靠性。此外,本发明在熔接系统中未插入其他光学元件,操作过程简单,将推进大模场光子晶体光纤的更多实际应用。(The invention belongs to all -fiber technical field, specially a kind of low-loss of large mode area pcf, high-intensitive welding process.The method of the present invention includes: to obtain two kinds to welding optic fibre, and first is greater than the second mode field diameter to welding optic fibre to the mode field diameter of welding optic fibre, and first is greater than the second cladding diameter to welding optic fibre to the cladding diameter of welding optic fibre；To second to welding optic fibre carry out it is reversed draw cone and thermotropic expansion core mixed processing, make second to welding optic fibre mode field diameter and cladding diameter in the first matching range to welding optic fibre；By first, to welding optic fibre and hybrid technology, treated second carries out welding to welding optic fibre.Welding process proposed by the present invention, splice loss, splice attenuation is ultralow, fusion point high mechanical strength, increases the reliability of large mode area pcf in actual application.In addition, the present invention is not inserted into other optical elements in welding system, operating process is simple, will promote more practical applications of large mode area pcf.)

1. a kind of low-loss of large mode area pcf, high-intensitive welding process, which is characterized in that specific steps include:

Step 1: obtaining two kinds to welding optic fibre, wherein first is greater than to the mode field diameter of welding optic fibre second to welding optic fibre Mode field diameter, first to welding optic fibre cladding diameter be greater than the second cladding diameter to welding optic fibre；

Step 2: to described second to welding optic fibre carry out it is reversed draw cone and thermotropic expansion core mixed processing, make second to welding optic fibre Mode field diameter and cladding diameter in the described first matching range to welding optic fibre；

Step 3: by described first, to welding optic fibre and hybrid technology, treated second carries out welding to welding optic fibre.

2. the method according to claim 1, wherein before step 2 further include:

Calculate the described first mode field diameter to welding optic fibre；

It calculates described second and draws cone by reversed to welding optic fibre, cladding diameter is matched with first to the cladding diameter of welding optic fibre When corresponding mode field diameter.

3. according to the method described in claim 2, it is characterized in that, step 2 includes:

Setting optical fiber to draw cone machining, which is drawn, bores parameter, and second to welding optic fibre described in heating and reverse propulsion, after the reversed drawing of completion is bored Cladding diameter of the measurement second to welding optic fibre；

By estimate cladding diameter situation of change, find it is described two when welding fibre cladding diameter matches situation is best, The parameter of optical fiber to draw cone machining.

4. according to the method described in claim 3, it is characterized in that, step 2 further include:

It finely tunes parameter near the cladding diameter optimum matching parameter, and by increasing the thermotropic time for expanding core technology, makes the The two mode field diameter expansion to welding optic fibre, and second is measured to welding optic fibre and the first algnment loss to welding optic fibre；

When the algnment loss minimum, it is best for finding described two match to welding fibre cladding diameter with mode field diameter When optical fiber to draw cone machining parameter.

5. method according to claim 4 or 5, which is characterized in that the optical fiber to draw cone machining parameter includes:

Hot advance distance, oxyhydrogen flame temperature, heating time, duration and degree of heating scanning speed and range.

6. the method according to claim 1, wherein step 3 further include:

By second after mixed processing, to welding optic fibre, from covering, most slightly point is cut off；

The thicker one end of cladding diameter is aligned with described first to welding fiber core.

7. according to method described in claim 3 or 4 or 6, which is characterized in that the process of two kinds of optical fiber aligns includes:

Power meter is connected to described first one end to welding optic fibre；

Laser is connected to described second one end to welding optic fibre；

By described first to welding optic fibre the other end with second to welding optic fibre other end transverse shifting and be aligned, and observe The registration of power meter in moving process；

When the power meter registration maximum, welding can be carried out based on default splicing parameter.

8. the method according to the description of claim 7 is characterized in that the welding based on default splicing parameter include:

Fibre core and covering physical structure based on first to welding optic fibre, adjustment splicing parameter carry out welding；

Wherein, the splicing parameter include predispersed fiber advance from, optical fiber pick with a distance from, heating time, heating power, duration and degree of heating biasing Distance.

9. according to the method described in claim 8, it is characterized in that, described first to welding optic fibre be large mould field photon crystal light Fibre, described second to welding optic fibre be conventional single mode fiber.

Technical field

The invention belongs to all -fiber technical fields, and in particular to a kind of large mode field, big outer diameter photonic crystal fiber it is molten Connect method.

Background technique

Large mode area pcf, core size are greater than conventional single mode fiber, have big mode field area, low nonlinearity The significant advantages such as coefficient, high laser damage threshold, endless single mode, therefore be widely used in high-capacity optical fiber laser, produce The fields such as raw and transmission high power super continuous spectrums, bio-photon imaging fiber.

In the practical application for being related to large mode area pcf, for example, by the laser coupled of laser emitting To wherein when, a kind of conventional method is by the way of free space coupling.But the unique airport knot of photonic crystal fiber Structure causes when it is chronically exposed in air, and end face structure is destroyed, so that coupling efficiency substantially reduces；In addition, freely empty Between the mode that couples reduce the integrated level of system, thus whole system is difficult keeping original optical characteristics once realizing On the basis of moved again, this brings numerous inconvenience to actual use.It is according to another method, laser tail optical fiber is (big Mostly conventional single mode fiber) and photonic crystal fiber progress low-loss, high-intensitive welding, the above problem can be solved.Wherein, The splice loss, splice attenuation of two kinds of optical fiber is related with the mould field matching degree of optical fiber, and heat seal strength has in the covering matching degree of optical fiber It closes.But between large mode area pcf and conventional single mode fiber often exist have notable difference mode field diameter and Cladding diameter, therefore complete the great challenge of welding of high quality.For example, a kind of large mode area pcf LMA-25, outside Diameter is 258 μm, and the mode field diameter under 1550 nm wavelength is about 20 μm, and conventional single mode fiber, such as SMF-28, outer diameter are 125 μm, the mode field diameter under 1550 nm wavelength is about 10.4 μm.

The existing reported welding process for large mode area pcf, is mainly the following.D. J. J. Hu et al. carries out welding by the way of arc discharge.Discharge power is improved in order to increase heat seal strength, leads to fusion point The airport of place's large mode area pcf collapses, therefore insertion loss greatly increases, about 6 dB.C.Jollivet et al. Using the Self imaging effect of graded index multimode fiber, inserted using the designed multimode fibre of a segment length as mould field adapter Enter between the large mode area pcf and conventional single mode fiber to welding.At this moment right in order to improve the intensity of joint The outer diameter of large mode area pcf makes chemical erosion, however the outer diameter after corroding still with conventional single mode fiber difference compared with Greatly, cause heat seal strength not high.In addition, the single fusion point loss of this method is still up to 4 dB.Patent document CN 107765368 A disclose a kind of welding process of hollow antiresonance optical fiber, and hollow antiresonance optical fiber mode fields therein are equally big In conventional single mode fiber, but it is mentioned that welding process only include conventional single mode fiber is done it is thermotropic expand core technology processing, To realize the matching of two kinds of optical fiber mode fields.0366320 B1 of patent document EP refers to handle by the way of reversed drawing cone Small core optical fibers form the shorter taper region of variation of transition region, are improved by the Mode change of single mode in this region to multimode With the coupling efficiency of large core fiber.Above two inventions relate only to the beam spread by small core optical fibers, improve two kinds The efficiency of light is transmitted between optical fiber, but does not refer to the covering matching and heat seal strength problem of optical fiber.

Summary of the invention

The object of the present invention is to provide a kind of low-losses, high-intensitive large mode area pcf welding process.

The present invention provides large mode area pcf welding process, specific steps are as follows:

Step 1: two kinds are obtained to welding optic fibre, wherein first is greater than second to welding optic fibre to the mode field diameter of welding optic fibre Mode field diameter, first to welding optic fibre cladding diameter be greater than the second cladding diameter to welding optic fibre；

Step 2: to described second to welding optic fibre carry out it is reversed draw cone and thermotropic expansion core mixed processing, make second to welding optic fibre Mode field diameter and cladding diameter in the described first matching range to welding optic fibre；

Step 3: by described first, to welding optic fibre and hybrid technology, treated second carries out welding to welding optic fibre.

Wherein, before step 2 further include:

Calculate the described first mode field diameter to welding optic fibre；

It calculates described second and draws cone by reversed to welding optic fibre, cladding diameter is matched with first to the cladding diameter of welding optic fibre When corresponding mode field diameter.

Wherein, step 2 includes:

Setting optical fiber to draw cone machining, which is drawn, bores parameter, and second to welding optic fibre described in heating and reverse propulsion, after the reversed drawing of completion is bored Cladding diameter of the measurement second to welding optic fibre；

By estimate cladding diameter situation of change, find it is described two when welding fibre cladding diameter matches situation is best, The parameter of optical fiber to draw cone machining.

Wherein, step 2 further include:

It finely tunes parameter near the cladding diameter optimum matching parameter, and by increasing the thermotropic time for expanding core technology, makes the The two mode field diameter expansion to welding optic fibre, and second is measured to welding optic fibre and the first algnment loss to welding optic fibre；

When the algnment loss minimum, it is best for finding described two match to welding fibre cladding diameter with mode field diameter When optical fiber to draw cone machining parameter.

Wherein, the optical fiber to draw cone machining parameter includes:

Hot advance distance, oxyhydrogen flame temperature, heating time, duration and degree of heating scanning speed and range.

Wherein, step 3 further include:

By second after mixed processing, to welding optic fibre, from covering, most slightly point is cut off；

The thicker one end of cladding diameter is aligned with described first to welding fiber core.

Wherein, the process of two kinds of optical fiber aligns includes:

Power meter is connected to described first one end to welding optic fibre；

The laser that wavelength is 1550 nm is connected to described second one end to welding optic fibre；

By described first to welding optic fibre the other end with second to welding optic fibre other end transverse shifting and be aligned, and observe The registration of power meter in moving process；

When the power meter registration maximum, welding can be carried out based on default splicing parameter.

Wherein, the welding based on default splicing parameter include:

Fibre core and covering physical structure based on first to welding optic fibre, adjustment splicing parameter carry out welding；

The splicing parameter include predispersed fiber advance from, optical fiber pick with a distance from, heating time, heating power, duration and degree of heating offset or dish.

In the present invention, described first to welding optic fibre be large mode area pcf.Described second is to welding optic fibre Conventional single mode fiber.

Optical fiber splicing method proposed by the present invention, by reversely drawing cone and thermotropic expansion core technology mixed processing to wait for welding tradition After single mode optical fiber, can it match each other with the covering and mould field of the large mode area pcf to welding, gained splice loss, splice attenuation It is ultralow, fusion point mechanical strength is higher, increase the reliability of large mode area pcf in actual application.

In addition to this, the present invention is not inserted into other optical elements in welding system, and operating process is simple, will promote big mould More practical applications of field photon crystal optical fiber.

Detailed description of the invention

Fig. 1 is the flow chart of optical fiber splicing method of the present invention.

Fig. 2 be large mode area pcf used in optical fiber splicing method of the present invention with conventional single mode fiber identical Cross-sectional view under scale.

Fig. 3 is to carry out reversed draw in optical fiber splicing method of the present invention to welding optic fibre to second and bore technical treatment, by changing Become the parameter of optical fiber to draw cone machining, the optical fiber side figure of obtained different lumbar region diameters.

Fig. 4 is to carry out reversed draw in optical fiber splicing method of the present invention to welding optic fibre to second and bore and thermotropic expansion core technology After mixed processing, by changing optical fiber to draw cone machining parameter, under the irradiation of white light source, the optical fiber of obtained different mould field sizes End view drawing.

Fig. 5 is the matching of obtained covering, the matched welding point diagram of mould field using the welding process proposed in the present invention.

Figure label: 1- large mode area pcf, 2- draw cone and thermotropic expansion core technology mixed processing to cross through reversed Conventional single mode fiber.

Specific embodiment

In order to more clearly state the purpose of the present invention and advantage, below in conjunction with attached drawing, the present invention is made further detailed It is thin to illustrate.The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention..

Fig. 1 is a kind of welding process flow chart of large mode area pcf provided in an embodiment of the present invention, comprising:

Step 1: two kinds are obtained to welding optic fibre, wherein described first is greater than second to welding light to the mode field diameter of welding optic fibre Fine mode field diameter, first is greater than the second cladding diameter to welding optic fibre to the cladding diameter of welding optic fibre；

Step 2: to described second to welding optic fibre carry out it is reversed draw cone and thermotropic expansion core mixed processing, make second to welding optic fibre Mode field diameter and cladding diameter in the described first matching range to welding optic fibre；

Step 3: by described first, to welding optic fibre and hybrid technology, treated second carries out welding to welding optic fibre.

A kind of hybrid technology based on reversely drawing cone and thermotropic expansion core of proposition of the embodiment of the present invention optimizes splicing parameter Optical fiber splicing method, the purpose is to solve the covering of large mode area pcf and conventional single mode fiber and mould field to mismatch band The problem that the heat seal strength come is low, loss is big.In the embodiment of the present invention, large mode field photon is brilliant after the method provided realizes welding The air pore structure of body optical fiber is not destroyed, and guiding property is unchanged, and while completing extremely low splice loss, splice attenuation, it is strong to improve welding Degree.

In step 1, the first of acquisition is approximately second to welding light to the cladding diameter and mode field diameter of welding optic fibre respectively 2 times of the corresponding diameter of fibre.

In step 2, reversed drawing cone technology is compressed, is obtained to it while heating to optical fiber localized hyperthermia Structure includes that intermediate one section of diameter thicker uniform waist and the transition of two sides two, the transition of two sides are connected to untreated light Fine part.By this technical treatment optical fiber, available expected cladding diameter size, and this process can realize it is extremely low Loss.Thermotropic expansion core technology is heated to optical fiber localized hyperthermia, and the germanium ion adulterated in fibre core can gradually be spread to covering, in turn The mode field diameter of optical fiber becomes larger.This technology in the case where not changing cladding diameter, can change the mould field size of optical fiber, and This process can also realize extremely low loss.To second after welding optic fibre carries out the mixed processing of above two technology, covering Diameter and mode field diameter can effectively increase, and match with first to welding optic fibre.

It, can before step 2, first with finite element analysis software simulation calculation first based on the explanation of above step 2 Draw cone technology, cladding diameter with first to welding optic fibre by reversed to welding optic fibre to the mode field diameter of welding optic fibre and second Mode field diameter when matching.Through calculating, obtain covering exact matching when, second to welding optic fibre mode field diameter it is still less than normal, Then mould field can be further increased by thermotropic expansion core technology.

Based on the explanation of above step 2, the embodiment of the present invention in the actual operation process, using optical fiber to draw cone machining, passes through Adjust the parameters such as hot advance distance, oxyhydrogen flame temperature, heating time, duration and degree of heating scanning speed and the range of optical fiber to draw cone machining, heating And reverse propulsion second finds parameter when cladding diameter matching by many experiments to welding optic fibre.In the matched base of covering On plinth, increases thermotropic expansion core technical role second to the time on welding optic fibre, increase its mould field.By second to welding light Fibre is placed on optical fiber splicer with first to welding optic fibre from covering most slightly point cutting.Wherein untreated one end connection The laser of 1550 nm, thick one end is with first to welding optical fiber align.First other end connection power to welding optic fibre Meter, by the transverse shifting of two kinds of optical fiber, to quasi-fiber and records alignment power.When different thermotropic expansion core technical roles are set Between, the measurement of above-mentioned alignment power is carried out to welding optic fibre to different second, finds drawing cone machine ginseng when alignment power maximum Number.

In step 3, for the embodiment of the present invention in fusion process, the optical fiber splicer used utilizes graphite heating silk component pair Optical fiber heating.Have been turned off after mixed processing under cone machine parameter first is drawn to set with second to welding optic fibre to welding optic fibre by best In being aligned on optical fiber splicer, connecting laser and power meter.Based on default splicing parameter, under axially aligned distance, laterally Fiber position is adjusted, when power meter registration maximum, welding is carried out based on default splicing parameter.

Default splicing parameter in step 3 mainly has: predispersed fiber advance from, optical fiber pick with a distance from, heating time, heating function Rate, duration and degree of heating offset or dish etc..In view of the air pore structure in the large mode area pcf to welding, the embodiment of the present invention By optimizing the above parameter, limitation airport is collapsed, and reduces splice loss, splice attenuation, while increasing heat seal strength.

Fig. 2 is cross section picture of two kinds of optical fiber under same scale used in the embodiment of the present invention.Wherein, (a) is Large mode area pcf is (b) conventional single mode fiber.

Fig. 3 be to second to welding optic fibre carry out it is reversed draw cone technical treatment, by change optical fiber to draw cone machining pick into The parameters such as distance, oxyhydrogen flame temperature, heating time, duration and degree of heating scanning speed and range, the optical fiber side of obtained different lumbar region diameters Face schematic diagram.

Fig. 4 is to draw cone by reversed to welding optic fibre second, with first to welding fibre cladding it is matched on the basis of, adjust Whole thermotropic expansion core technical role, to the time on welding optic fibre, increases its mould field, under the irradiation of white light source, obtains second The fiber end face schematic diagram of the different mould field sizes arrived.

Fig. 5 is to be carried out to welding optic fibre and second to welding optic fibre using the welding process proposed in the present invention to first The welding schematic diagram that welding obtains.It is observed that the covering matching of two kinds of optical fiber, and first does not occur to welding optic fibre side Airport collapses.

On the basis of the above embodiments, described first is large mode area pcf to welding optic fibre.

It should be noted that first is solid core silica to the fibre core of welding optic fibre, covering includes the regular hexagon period Property arrangement airport.

On the basis of the above embodiments, described second is conventional single mode fiber to welding optic fibre.

It should be noted that used in the embodiment of the present invention two kinds to welding optic fibre be other meet described in step 1 Other kind of optical fiber when, can pass through the welding process in the invention reduce splice loss, splice attenuation and improve heat seal strength., but it is preferable that Provided in an embodiment of the present invention is large mode area pcf and conventional single mode fiber.

Finally, the present processes are only preferable embodiment, it is not intended to limit the scope of the present invention.It is all Within the spirit and principles in the present invention, any modification, equivalent replacement, improvement and so on should be included in protection of the invention Within the scope of.