TWI684036B - Optical fiber with filtering function and forming method thereof - Google Patents

Abstract

The invention relates to an optical fiber with a filtering function and a forming method thereof, in particular, at least two optical fibers from which a coating layer has been removed are brought close to each other, and a heated part is heated to fuse a plurality of optical fibers into one body, and then the optical fibers are opposed External stretching, and then the melting portion of the optical fiber is stretched to form a double cone shape, and after the melting portion of the double cone shape is cooled, the melting portion of the optical fiber can be formed into a cone portion to filter out by the cone portion A high-order modal light with a preset ratio, and through this method, the cone portion can be formed simply and quickly without additional materials, which makes the cost low and suitable for mass production, thereby achieving the purpose of enhancing market competitiveness.

Description

Optical fiber with filtering function and forming method thereof

The invention provides an optical fiber with a filtering function and a forming method thereof, in particular, the at least two optical fibers only need to pass through heating and drawing processes to quickly obtain a double-cone shape and a high-order mode for filtering a preset ratio The cone of light, without the need to purchase additional materials, so that the cost is low, suitable for mass production, thereby achieving the effect of enhancing market competitiveness.

With the advent of the high-tech era, the processing technology of industrial manufacturing production has been continuously improved. The traditional mechanical processing process can only process the appearance of the processed objects, but it is impossible for the processing, engraving or cutting of the processed objects. Completion, in addition to high-tech semiconductor products such as wafers, components, thin-plate drilling, cutting, etc., can not be processed; therefore, the laser processing process has been developed, and the process is widely used. In the fields of precision industry, excitation detection, spectroscopy, or plasma dynamics, all processes can be processed through lasers. Traditional laser processing cannot avoid mechanical clamping of lenses, high-precision translation stages, etc., but through optical lasers For laser processing of pulsed light, optical fiber lasers have the advantages of compact structure, high efficiency and the ability to produce high-quality laser beams. Therefore, optical fiber lasers are widely used in the process of material processing. The radiation has the advantages of very good stability, small size, easy to carry and easy to set up, so it has a place in the application of optical communication, spectral measurement and optical analysis, and because of its very good good collimation and high The power and high light intensity also make the laser source processing system widely used in industry.

In addition, the current industrial high-power laser source processing systems (such as the laser system with a master optical fiber amplifier (Master Oscillator Power Amplifier) architecture) are filtered out in order to make the system more stable. Some high-order modal light in the optical fiber, however, in general laser processing systems, to filter out the high-order modal light in the optical fiber, it is necessary to additionally design a filter mechanism in the laser machine, or filter the optical fiber Processing operations (such as: replacing the cladding layer of the optical fiber with a material with a higher refractive index so that high-order modal light can be refracted outward), but nowadays, whether it is an additional design of a filter mechanism or a filter of the optical fiber Light processing operations require a lot of processing processes and manufacturing costs, so that production time and costs are high.

Therefore, how to solve the above-mentioned lack of inconvenience and inconvenience is the direction of improvement for those engaged in this industry.

Therefore, in view of the above-mentioned deficiencies, the inventors collected relevant data, evaluated and considered through multiple parties, and based on years of experience in this industry, through continuous trial and modification, they began to design such optical fibers with filtering functions and their formation The patentee of the method.

The main purpose of the present invention is that the at least two optical fibers with the coating layer removed are fused together by heating operation, and a double-cone-shaped tapered portion is formed by relatively drawing out using a drawing process, To filter out high-order modal light with a preset ratio, at least two optical fibers need to be heated and stretched to quickly form the tapered portion without additional materials, which makes the cost low and suitable for mass production. To achieve the purpose of enhancing market competitiveness.

The secondary objective of the present invention is that the tapered portion of the optical fiber is filterable to a preset ratio The high-order modal light can be widely used in various external laser machines and used with sensors to know whether there is light passing through this fiber and whether the power of the passing light is in line with the external laser machine. Use requirements, and then achieve the purpose of protecting external laser source devices and multi-purpose.

1‧‧‧ Fiber

11‧‧‧Core

12‧‧‧cladding

13‧‧‧Cone

2‧‧‧Sensor

The first figure is a flowchart of the present invention.

The second figure is a schematic diagram of the invention before welding.

The third figure is a schematic diagram of the present invention during stretching.

The fourth figure is a front view of the present invention.

The fifth figure is a diagram of the use state of the invention.

In order to achieve the above-mentioned objectives and effects, the technical means and structure adopted by the present invention, the drawings and details of the preferred embodiments of the present invention are described in detail below. Their features and functions are as follows, so that they can fully understand.

Please refer to the first, second, third and fourth figures, which are the flow chart of the present invention, the schematic diagram before welding, the schematic diagram and the front view during stretching, as can be clearly seen from the figure, the invention has a filtering function The optical fiber 1 includes a core 11 and is coated with a cladding 12 on the core 11, and at least one tapered portion 13 in the shape of a double cone is formed on the optical fiber 1, and the tapered portion 13 expands outward from the center .

The above-mentioned optical fiber 1 can be a multi-mode optical fiber, a double-shell fiber, a polarization maintaining fiber, or a gain fiber, etc., which can be used to transmit high-order mode light.

The optical fiber 1 with filtering function of the present invention can be manufactured according to the following forming method , The steps include:

(A) First, at least two optical fibers 1 from which the coating layer has been removed are brought close to each other, and the close parts are heated to fuse the plural optical fibers 1 into one body, and the close parts are in a molten state.

(B) The optical fiber 1 is drawn relatively outward to deform the core 11 and the cladding 12 at the fusion site, and then the fusion site is stretched to form a double cone shape.

(C) Cooling the double-cone-shaped melting part to form the tapered part 13 at the melting part of the optical fiber 1, thereby completing the optical fiber 1 with a filtering function.

In the above step (B), after the core 11 of the optical fiber 1 is stretched, the diameter of the core 11 is gradually reduced.

The present invention is capable of bringing the ends of at least two coated optical fibers 1 close to each other and using an external heating device (such as: a fusion splicer, a discharge heater, or other devices capable of high-temperature heating; not shown in the figure) To heat the close parts, when the close parts are heated, they will be in a molten state, which can be driven by a stretching device (such as: a stepping motor; not shown in the figure) to drive the plurality of optical fibers 1 Drawing axially relatively outwards, so that the wire diameters of the core 11 and the cladding 12 at the melting part gradually become smaller with the outward stretching, and then the melting part is stretched to form a double cone shape, and then a plurality of optical fibers 1 Place the cooling or use a cooling device to cool, thereby cooling the molten portion of the plurality of optical fibers 1 to form a tapered portion 13 to complete the production of the optical fiber 1 with a filtering function.

，而該參數a為光纖纖心(Core)的半徑、NA為數值孔徑(Numerical Aperture)、λ為真空中光波長，然而，當正規化頻率(V)小於2.405時，就代表光會以單模態的型式在光纖1中進行傳輸作業，所以光纖1之纖芯11透過拉伸作業後，會使其半徑縮小，而當光通過光纖1之錐部13時，即會有預設比例的高階模態光無法通過，而向外部折射，以使光會趨近單模態或以單模態的型式在光纖1中傳輸。 In addition, the normalized frequency (Normalized Frequency; V Number) in fiber optics is used to describe the mode of light traveling in the optical fiber 1, and the formula for the normalized frequency is

, And the parameter a is the radius of the fiber core (Core), NA is the numerical aperture (Numerical Aperture), λ is the wavelength of light in vacuum, however, when the normalized frequency (V) is less than 2.405, it means that the light will be single The modal type is transmitted in the optical fiber 1. Therefore, after the core 11 of the optical fiber 1 passes through the drawing operation, its radius will be reduced, and when the light passes through the tapered portion 13 of the optical fiber 1, there will be a preset ratio The high-order mode light cannot pass through, but is refracted to the outside, so that the light will approach the single mode or be transmitted in the optical fiber 1 in a single mode.

However, please refer to the fifth figure, which is the use state diagram of the present invention. It can be clearly seen from the figure that when the light passes through the tapered portion 13 of the optical fiber 1, there will be a preset ratio of high-order mode light to the outside Refraction, so the double-cone fiber 1 of the present invention can be used as a passive optical element to be used in various laser source devices [such as: all-fiber type main oscillator source amplifier (Master Oscillator Power Amplifier)], and with It can be used by a sensor 2 (such as a photoelectric sensor) that detects the light output. The sensor 2 is a high-order mode light that can detect the outward refracted at the tapered portion 13 of the optical fiber 1 to learn Whether the optical fiber 1 passes through or not, and whether the power of the passing light meets the requirements of use, it can be used with the sensor 2 as a monitoring and detection device, thereby having the effect of protecting the laser source device.

In addition, the fiber diameter a, the cone waist diameter b, the taper length c, the cone angle θ and other parameters of the tapered portion 13 of the above-mentioned optical fiber 1 will affect the preset ratio of high-order mode light refracting outward, and the size of each parameter can be based on The laser source device used is designed, here is an example to illustrate, The diameter of the optical fiber 1 is 250 μm, the diameter of the core 11 is 30 μm, and a stretching device with a preset taper speed is used for drawing to form a tapered waist diameter of 125 μm, a tapered waist length of 3 mm, and a drawn tapered length of 5 mm The tapered portion 13 of the optical fiber 1, and when the tapered portion 13 of the optical fiber 1 is used at a wavelength of 1064 nm, a proper normalized frequency (V) is obtained at the tapered portion 13, and the normalized frequency obtained is close to single mode State light transmission, so that high-order mode light can be refracted outward stably, and can be used for the sensor 2 in the laser source device.

The present invention has the following advantages:

(1) The at least two optical fibers 1 only need to be fused by heating, and then a plurality of optical fibers 1 are stretched out to form a double-cone-shaped tapered portion 13 by a drawing process, which can be used The part 13 is used to filter out high-order modal light of a preset ratio. The method of forming the tapered part 13 is simple and fast, and can be made only by using the material characteristics of the optical fiber 1 without additional materials, which makes the cost low , Suitable for mass production, so as to achieve the effect of enhancing market competitiveness.

(2) The tapered portion 13 of the optical fiber 1 can filter out high-order modal light of a preset ratio, so that the optical fiber 1 can be widely used in various external laser machines and used with the sensor 2 to obtain It is known whether there is light passing through this optical fiber 1 and whether the power of the passing light meets the use requirements of the external laser machine, and thus has the effect of protecting the external laser source device and multi-purpose.

The above detailed description is for the description of a preferred feasible embodiment of the present invention, but this embodiment is not intended to limit the scope of the patent application of the present invention. Any other changes and modifications made without departing from the spirit of the art disclosed by the present invention Changes should be included in the scope of patents covered by the present invention.

In summary, the optical fiber with filtering function and its forming method of the present invention are used in At this time, in order to indeed achieve its efficacy and purpose, the present invention is truly an invention with excellent practicability. In order to meet the requirements for the application of an invention patent, you must file an application in accordance with the law. I hope the review committee will grant this case as soon as possible to protect the inventor’s hard work For inventions, if there is any doubt in the review committee of the Jun Bureau, please send me a letter and give instructions, the inventor will definitely try his best to cooperate, and feel virtuous.

Claims (7)

An optical fiber with a filtering function. The optical fiber includes a fiber core and is coated with a cladding on the fiber core, characterized in that at least one biconical shape is formed on the fiber and is used for filtering out a preset ratio The tapered part of the high-order modal light is a double-cone-shaped optical fiber that is a passive optical element used in various laser source devices and uses a sensor to detect the tapered part of the optical fiber The high-order mode light refracted outwards, knowing whether the optical fiber passes through, and whether the power of the passing light meets the use requirements, and is used as a monitoring and detection device with the sensor. The optical fiber with filtering function as described in item 1 of the patent scope, wherein the optical fiber is a multimode fiber, a double-shell fiber, a polarization maintaining fiber or a gain fiber. The optical fiber with filtering function as described in item 1 of the patent application scope, wherein the tapered portion of the optical fiber expands outward from the center. A method for forming optical fiber with filtering function includes the following steps: (A) First, at least two optical fibers with the coating layer removed are brought close to each other, and the close parts are heated to fuse the plural optical fibers into one, And the close part is in a molten state; (B) The optical fiber is stretched relatively outward to deform the core and the cladding at the molten part, and then the molten part is stretched to form a double cone shape; (C ) The double-cone-shaped melting part is cooled to form a tapered part in the melting part of the optical fiber. The optical fiber in the form of a double-cone is a passive optical element, which is applied to various laser source devices, and uses a The sensor detects high-order modal light refracted outward at the tapered portion of the fiber to know whether the fiber passes through and the power of the passing light Whether it meets the needs of use, with the sensor as a monitoring and detection device. The method for forming an optical fiber with a filtering function as described in item 4 of the patent scope, wherein the optical fiber is a multimode fiber, a double-shell fiber, a polarization maintaining fiber, or a gain fiber. The method for forming an optical fiber with a filtering function as described in item 4 of the patent application scope, wherein in step (B), the plural optical fibers are drawn relatively outward in the axial direction. The method for forming an optical fiber with filtering function as described in item 4 of the patent application scope, wherein the tapered part of the optical fiber in this step (C) expands outward from the center.

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