TWI484232B - Method for manufacturing a tunable long-period fiber grating - Google Patents

Description

Adjustable variable length period fiber grating manufacturing method

The invention relates to a method for manufacturing a variable length and long period fiber grating, in particular to a method for producing a variable length and long period fiber grating by screen printing technology.

Referring to FIG. 1 , the manufacturing method of the conventional variable length-period fiber grating mainly comprises the following steps: pre-stripping one of the outermost layers of a fiber, and coating one of the fibers (Cladding) Forming an exposed; then, uniformly coating a photoresist layer directly on the coating layer of the optical fiber, and heating the photoresist layer for soft baking; using the ultraviolet light to match a photomask to complete the soft-baking partial photoresist layer Exposing, the exposed partial photoresist layer produces a photopolymer chain, and a core of the fiber is also formed into a plurality of portions having different refractive indices after being irradiated by ultraviolet light; The unexposed photoresist layer is removed by a developing solution, so that the photoresist layer can form a protective layer on the coating layer of the optical fiber; and then, the optical fiber is covered by the protective layer without using an etching solution. The coating is etched to etch a groove structure on the cladding layer of the optical fiber; finally, the protective layer is removed by another etching solution, thereby forming a tunable change with a zigzag geometry on the outer surface of the optical fiber. Long period fiber light Finished.

The manufacturing method of the conventional variable length and long-period fiber grating is mainly to form the zigzag geometric structure by using the developing solution and different etching liquids to directly etch from the surface of the photoresist layer to the core of the optical fiber. The developer etching time directly affects the size of the zigzag geometry, and the developer is considered in consideration of the etching time and the etching depth. Type, photoresist material and other environmental parameters (eg temperature, etc.), so the etching time is extremely difficult to master, resulting in the deviation of the finished product size when forming the sawtooth geometry in the conventional way, especially in the formation of the zigzag geometry. When the concave portion of the structure (the concave portion between the respective tooth portions) is formed, the etching time is too long to damage the coating layer of the optical fiber, or the etching time is too short, and the dimensional accuracy such as the depth of the concave portion is insufficient.

In order to solve the above problems, please refer to the second and third figures, which are another conventional variable length and long-term fiber grating disclosed in the Patent Publication No. I394993 of the Republic of China Patent No. I394993, "Manufacturing Method of Adjustable Variable Length Fiber Gratings". The method is as follows: directly forming a first geometric structure 94 having a predetermined thickness on a substrate, and then stacking an optical fiber 91 and a second geometric structure 96 in a position above the first geometric structure to make the sawtooth The photoresist layer of the geometric structure is formed on the outer surface of the optical fiber, and the sawtooth geometry is formed by directly etching from the surface of the photoresist layer to the core of the optical fiber, which can effectively avoid the coating of the 91 fiber. The layer is damaged.

However, the above-mentioned conventional variable length and long-period fiber grating manufacturing methods are all fabricated by a conventional semiconductor thin film process, which requires many complicated steps such as photoresist spin coating, soft baking, exposure, development etching and hard baking, etc., resulting in complicated process steps and overall The process time is quite lengthy, with shortcomings such as insufficient capacity and high production costs.

In summary, there is a need to provide a further improved method for fabricating a variable length and long period fiber grating to improve the process efficiency of the variable length and long period fiber grating, thereby lowering the production cost to meet the industrial demand.

The object of the present invention is to provide a method for fabricating a variable length-period fiber grating, which is printed on the sacrificial layer by a screen printing technique to form a first geometric structure, and an optical fiber is fixed to the first geometric structure. Forming a second geometric structure on the first geometric structure by screen printing technology to form a variable length-period fiber grating with an elevated process The efficiency of efficiency.

A further object of the present invention is to provide a method for fabricating a variable length-period fiber grating, which uses the same master to print the second geometric structure and the first geometric structure to simplify process complexity and has adjustable reduction The efficiency of the production cost of variable length periodic fiber gratings.

In order to achieve the foregoing object, the technical means used in the present invention comprises: a method for fabricating a variable length-period fiber grating, the steps comprising: removing a fiber layer of an optical fiber in advance, and etching and reducing the coating layer of the fiber; a thickness of 10 to 125 μm; forming a sacrificial layer on a surface of the substrate by physical vapor deposition, chemical vapor deposition or bonding; printing a first geometric structure on the sacrificial layer by a screen printing machine The first geometric structure is a plurality of successively arranged bumps; the optical fiber from which the fiber coating layer has been removed is fixed on the first geometric structure; and the screen printing machine is printed on the first geometric structure to form a The second geometric structure, the second geometric structure is also a plurality of successively arranged bumps, and the image recognition surface capture image is captured by a photographing device to obtain an image of the surface of the substrate, and the image analysis operation is performed by an operation unit to identify the second geometrical structure. a geometric configuration that precisely aligns the second geometric configuration with the first geometric configuration to stack the second geometric configuration over the first geometric configuration, and the first Geometric configuration and the first common line geometry coated surface outside of the optical fiber; and removing the etching solution by using a sacrificial layer.

The method for fabricating the variable length-period fiber grating of the present invention, wherein the screen printing machine uses the photoresist, the silver paste or the UV offset to print the first geometric structure and the second geometric configuration.

The method for fabricating the variable length-period fiber grating of the present invention, wherein the screen printing machine prints the first geometric structure on the sacrificial layer, and then irradiates the first geometric structure with ultraviolet light for curing And after the screen printing machine is printed on the first geometric structure to form the second geometric structure, the second geometric configuration is then irradiated with ultraviolet light for curing.

The manufacturing method of the adjustable variable length period fiber grating of the invention, wherein the ultraviolet Light is produced by an adjacent printer.

The manufacturing method of the adjustable variable length period fiber grating of the invention, wherein the sacrificial layer is a metal film.

In the method for fabricating the variable length-period fiber grating of the present invention, the sacrificial layer is made of copper and attached to the surface of the substrate by physical vapor deposition to form a copper film as the sacrificial layer.

In the method for fabricating the variable length-period fiber grating of the present invention, the substrate, the sacrificial layer and the first geometric structure are co-impregnated in the etching solution to remove the sacrificial layer.

The method for fabricating the variable length-period fiber grating of the present invention, wherein the etching solution is a ferric chloride solution, aqua regia, bromic acid or oxalic acid.

The method for fabricating the variable length-period fiber grating of the present invention, wherein the fiber-optic system is preliminarily removed by physical cutting or chemical etching to remove the fiber coating layer of the fiber, so that the coating layer of the fiber is exposed, and then The buffered oxidizing etchant reduces the thickness of the cladding layer by etching.

1‧‧‧Fiber

11‧‧‧Finishing layer

12‧‧‧coating

2‧‧‧Substrate

3‧‧‧ Sacrifice layer

4‧‧‧First geometry

5‧‧‧Second geometry

FIG. 1 is a schematic flow chart of a method for fabricating a conventional variable length and long period fiber grating.

Figure 2 is a flow chart showing another method for fabricating a conventional variable length and long period fiber grating.

Figure 3 is a schematic view showing the structure of a conventional variable length and long period fiber grating.

Figure 4 is a schematic flow diagram of a preferred embodiment of the present invention.

Figure 5 is a schematic view showing the structure of an optical fiber according to a preferred embodiment of the present invention.

Figure 6 is a schematic view showing the structure of a substrate of a preferred embodiment of the present invention.

Figure 7 is a schematic view showing the structure of the first geometrical structure of the preferred embodiment of the present invention.

Figure 8 is a schematic view showing the structure of the optical fiber of the preferred embodiment of the present invention and the first geometric configuration.

Figure 9 is a schematic view showing the structure of a second geometrical structure of a preferred embodiment of the present invention.

Figure 10 is a schematic view of the finished structure of the preferred embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Referring to FIG. 4, a flow chart of a preferred embodiment of the method for fabricating the variable length-period fiber grating of the present invention first requires an optical fiber 1 to be preset. The structure of the optical fiber 1 can be as shown in FIG. Show. The step of presetting the optical fiber 1 is to remove the fiber coating layer 11 of the optical fiber 1 by physical cutting or chemical etching, so that one of the coating layers 12 of the optical fiber 1 is exposed; and a buffered oxidizing etching solution is used (Buffer Oxide). Etcher, BOE) reduces the thickness of the cladding layer 12 to between 10 and 125 μm by etching, and the thickness of the cladding layer 12 preferably forms 85 μm, thereby effectively improving the optical fiber 1 in measuring the strain amount or Sensitivity of other physical quantities.

Referring to FIGS. 4 and 6, the method for fabricating the variable length-period fiber grating of the preferred embodiment is followed by forming a sacrificial layer 3 on the surface of a substrate 2, and the sacrificial layer 3 can be a metal film or A non-metallic film. In this embodiment, the sacrificial layer 3 is a metal thin film. The sacrificial layer 3 may be formed on the surface of the substrate 2 by physical vapor deposition (PVD), chemical vapor deposition (CVD) or bonding. The substrate 2 may be a germanium wafer substrate, a glass substrate, a ceramic substrate or a polymer substrate (for example, a PET substrate), etc., and the sacrificial layer 3 is preferably a metal film and can be used as The material of the sacrificial layer 3 is copper, and the invention is not limited thereto. Before the sacrificial layer 3 is formed, the surface of the substrate 2 is preferably cleaned in advance to remove impurities on the surface of the substrate 2, thereby improving the adhesion between the substrate 2 and the sacrificial layer 3. In this embodiment, the substrate 2 is made of a PET substrate, and the surface of the substrate 2 can be selectively cleaned by using ethanol or acetone; then, the sacrificial layer 3 is made of copper and can be attached to the substrate by physical vapor deposition. The surface of the material 2 is used to form a copper film as the sacrificial layer 3. Physical vapor deposition The system includes sputtering, evaporation, or ion plating, and the like can be understood by those having ordinary knowledge in the field to which the present invention pertains.

Referring to FIGS. 4 and 7, the manufacturing method of the variable length-period fiber grating of the preferred embodiment is further printed on the sacrificial layer 3 by a conventional screen printing machine through screen printing technology. The first geometric structure 4 is a plurality of successively arranged bumps, and in the embodiment, the first geometric structure 4 may be a plurality of equally spaced or non-equally spaced bumps (for example: rectangular blocks) ). The material for printing the first geometric structure 4 may be a photoresist, a silver paste or an ultraviolet adhesive (Ultraviolet Adhesive) or the like. In the embodiment, the first geometric structure 4 is made by using a photoresist. Since screen printing belongs to the core technology in the semiconductor thick film process, it can be easily understood by those having ordinary knowledge in the field to which the present invention pertains. The detailed process for printing the first geometric structure 4 will not be further described.

After the first geometric configuration 4 is printed, the first geometric structure 4 can be cured by ultraviolet light to shape the first geometric structure 4 into a solid and have a better structural strength. More specifically, in the embodiment, since the first geometric structure 4 is printed by a photoresist, an adjacent printer can be used to provide ultraviolet light having a specific wavelength and projected on the first a geometrical structure 4, a portion of the optical polymer in the first geometric structure 4 is linked to complete the curing; similarly, if the first geometric structure 4 is made of silver paste or UV offset, the same can be utilized separately. Ultraviolet light of a wavelength is projected onto the first geometry 4 for curing.

Referring to FIGS. 4 and 8, the method for fabricating the variable length-period fiber grating of the preferred embodiment is to fix the optical fiber 1 with the preset fiber-removed layer 11 on the first geometric structure 4. The optical fiber 1 can be fixed by external force or by forming a support on the substrate 2 to position the optical fiber 1. The invention is not limited (the inventor confirms the fixing manner of the optical fiber 1). Whether it needs to be achieved through specific technical means).

Please refer to Figures 4 and 9, the fiber 1 is indeed fixed to the first geometry. After the structure 4, the second geometric structure 5 is continuously printed on the first geometric structure 4 by the screen printing machine by the screen printing technology. In the embodiment, the photoresist is used to make the second. Geometry 5, and the second geometry 5 must be aligned with the first geometry 4 to ensure that the second geometry 5 can be accurately stacked over the first geometry 4 and wrap the fiber 1 Outside surface. The second geometric configuration 5 can be identical to the first geometric configuration 4, each of which is a plurality of rectangular blocks arranged in series. In this embodiment, the second geometric structure 5 and the first geometric structure 4 are rectangular blocks arranged at equal intervals, so when the second geometric structure 5 is printed, the first geometric structure 4 can be used and printed. The same master version. In addition, the alignment manner of the second geometric structure 5 and the first geometric structure 4 can be performed by arranging a positioning key commonly used in the conventional semiconductor process on the surface of the substrate 2 as the second geometric structure 5 is printed. The alignment of the second geometry 5 can be precisely aligned with the first geometry 4 by image recognition and positioning techniques. In detail, the image recognition and positioning technology can capture an image of the surface of the substrate 2 through a photographing device (for example, a CCD camera), and perform image analysis operations through an arithmetic unit (for example, a microprocessor) to identify The first geometric configuration 4 enables the second geometric configuration 5 to be accurately positioned relative to the first geometric configuration 4 when the conventional screen printing machine is printed.

It should be noted that the second geometric configuration 5 should be printed at least to a predetermined thickness such that the second geometric configuration 5 and the first geometric configuration 4 can completely cover the outer surface of the optical fiber 1. Wherein, the thickness of the cladding layer 12 of the optical fiber 1 is between about 10 and 125 μm, so the predetermined thickness may be 150 μm. After the printing of the second geometrical structure 5 is completed, the second geometrical structure 5 can likewise be cured by means of ultraviolet light.

Finally, the variably variable length period fiber grating of the preferred embodiment is fabricated by using an etchant to disengage the first geometry 4 from the sacrificial layer 3 to obtain a finished product of the tunable variable length fiber grating. In more detail, the substrate 2, the sacrificial layer 3 and the first geometric structure 4 are co-impregnated in the etching solution, wherein the etching layer 3 is a copper film in the embodiment, so the etching solution Preferably, it is selected from the group consisting of ferric chloride solution, aqua regia, bromic acid or oxalic acid, thereby removing The sacrificial layer 3. After the above steps are completed, the first geometric structure 4, the optical fiber 1 and the second geometric structure 5 together form a finished product of the adjustable variable length period fiber grating.

The main technical feature of the method for fabricating the variable length-period fiber grating of the present invention is that the present invention directly prints a first geometric structure 4 on the sacrificial layer 3 by screen printing technology, and fixes an optical fiber to the optical fiber. After the first geometrical configuration 4, a second geometric configuration 5 is printed on the first geometric structure 4 by screen printing techniques, by aligning the second geometric structure 5 with the first geometric structure 4. The second geometric structure 5 can be accurately stacked above the first geometric structure 4 to jointly form an adjustable variable length period fiber grating.

It can be seen that the manufacturing method of the adjustable variable length period fiber grating of the present invention can omit the photoresist spin coating, soft baking, exposure, development etching and hard baking, etc. compared with the conventional manufacturing method of the variable length and long period fiber grating. The complicated steps can effectively save the cost and time cost of the process equipment, and greatly increase the production capacity of the variable-length-length fiber grating, which has the effect of improving the process efficiency.

In addition, the method for fabricating the variable length-period fiber grating of the present invention is intended to be printed in the second geometric configuration above the first geometric structure 4, and may be the same as when the first geometric structure 4 is printed. The master version effectively simplifies the process complexity and does have the effect of further improving the efficiency of the process.

In summary, the manufacturing method of the adjustable variable length fiber grating of the present invention can greatly improve the process efficiency of the adjustable variable length fiber grating to reduce the production cost of the variable length and long period fiber grating.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

Claims (9)

A method for fabricating a variable length-period fiber grating comprises the steps of: removing a fiber layer of an optical fiber in advance, and etching and reducing a thickness of a coating layer of the fiber to 10 to 125 μm; physical vapor deposition, chemical vapor phase Depositing or laminating to form a sacrificial layer on a surface of the substrate; printing a first geometrical structure on the sacrificial layer by a screen printing machine, the first geometric configuration being a plurality of successively arranged bumps; The fiber from which the fiber coating layer has been removed is fixed on the first geometric structure; the second geometric structure is printed on the first geometric structure by the screen printing machine, and the second geometric structure is also arranged in several consecutive configurations. The bump is captured by an image capturing device to obtain an image of the surface of the substrate, and an image analysis operation is performed by an operation unit to identify the first geometric structure, and the second geometric structure and the first geometric shape are Constructing a precision alignment to form the second geometrical structure over the first geometrical structure, and the second geometrical structure and the first geometrical structure together cover the outer surface of the optical fiber ; And removing the etching solution by using a sacrificial layer. The method for fabricating a variable length-length fiber grating according to claim 1, wherein the screen printing machine uses a photoresist, a silver paste or a UV offset to fabricate the first geometric structure and the second Geometric construction. The method of manufacturing the variable length-period fiber grating of claim 2, wherein the screen printing machine prints the first geometric structure on the sacrificial layer, and then irradiates the light with ultraviolet light. The first geometric configuration is for curing; and after the screen printing machine is printed on the first geometric formation to form the second geometric configuration, the second geometric configuration is then illuminated with ultraviolet light for curing. The method for fabricating a variable length and long period fiber grating according to claim 3, wherein the ultraviolet light is generated by an adjacent printer. The method for fabricating a variable length and long period fiber grating according to claim 1, wherein the sacrificial layer is a metal film. The method for fabricating a variable length-length fiber grating according to claim 5, wherein the sacrificial layer is made of copper and attached to the surface of the substrate by physical vapor deposition to form a copper film. As the sacrificial layer. The method of fabricating the variable length-period fiber grating of claim 6, wherein the substrate, the sacrificial layer and the first geometric structure are co-impregnated in the etching solution to remove the sacrificial layer. The method for manufacturing the variable length-length fiber grating according to claim 7, wherein the etching solution is a ferric chloride solution, aqua regia, bromic acid or oxalic acid. The method for fabricating a variable length and long-term fiber grating according to claim 1, wherein the fiber is preliminarily removed by physical cutting or chemical etching to remove the fiber layer of the fiber, so that the fiber is covered. The layer is exposed to the surface, and the thickness of the cladding layer is reduced by etching using a buffered oxidizing etchant.