KR20110037776A - Method of manufacturing optical filter for multiplexing or demultiplexing - Google Patents

Abstract

PURPOSE: A method for manufacturing an optical filter for multiplexing or demultiplexing is provided to bidirectionally transceive light. CONSTITUTION: A filter layer(113) is formed between at least two optical transmitting plates(111,112) which transmits light which includes a corresponding wavelength so that a filter bonding object(110) is formed. V grooves(114) are formed on at least one side in parallel with a filter layer of the filter bonding object so that optical filters are consecutively formed using a cutting blade.

Description

Method for manufacturing optical filter for multiplexing or demultiplexing

The present invention relates to a method of manufacturing an optical filter that enables two-way optical transmission and reception by multiplexing or demultiplexing multi-wavelength light.

Recently, the optical transmission and reception technology has been shifted from the existing two-fiber form to one-fiber bidirectional optical subassembly (BOSA) form in order to reduce the cost of fiber laying and the line rent. In addition, a technology for enabling data transmission while two or more wavelengths traveling in two directions instead of one wavelength has been proposed in an optical fiber. For this purpose, an optical filter is required in the process of splitting a signal of a desired wavelength band from an optical signal of several wavelengths or combining the optical signal of several wavelengths to a single light beam.

Conventional optical filters include a fiber in line optical filter using a grating technology such as an optical fiber or a planar light-wave circuit (PLC), or an arrayed waveguide grating (AWG) and thin film coating technology. Has been applied. In addition, a filter using a difference in reflection angle according to a wavelength, such as an Echelle filter, has been applied. However, the fiber in-line filter still has many problems in mass productivity and reproducibility, and in the case of the Esher filter or the AWG, the miniaturization of the optical chip is difficult and expensive.

Currently, the most favorable filter for low cost and easy to mass-produce is a plate-type thin film filter using a thin film coating on a general light transmissive plate. However, the plate-type thin film filter has a disadvantage in miniaturization, and when the light is inclined at 45 degrees to change the optical path, the optical path change and the reflection loss on the inclined plane are large, and the optical axis must be aligned using a separate mechanical structure for multi-wavelength filtering. There is a hassle to do. In addition, it is difficult to implement a filter structure for multi-wavelength filtering, there is a problem that the offset (Offset) occurs in the path of the incident light according to the thickness of the plate. In order to solve this problem, a prism type optical filter has been proposed.

However, according to a conventional example, in order to mass-produce a prism type optical filter, a manufacturing method as shown in FIG. 1 is used. As shown in FIG. 1, the filter assembly 10 is cut to cross in the 45 degree direction by a file saw, a saw blade, or the like to manufacture a plurality of optical filters 20 in the form of a hexahedral two-wavelength filter. Here, the filter assembly 10 is manufactured by coating the filter layer 13 on one surface of the light transmissive plate 11 and then joining the other light transmissive plate 12 to abut the filter layer 13.

However, in the case described above, in order to cut the filter assembly 10, the narrow surface of the filter assembly 10 must be fixed and supported on the fixing plate 1 so that the filter layer 13 stands up. For this reason, since the area which the filter assembly 10 supports by the fixing plate 1 becomes small, the force which firmly supports the filter assembly 10 becomes weak, and precise cutting becomes difficult. When the filter assembly 10 is cut by a file saw or a saw blade, the cut portion of the optical filters 20 may be easily broken by the cutting resistance due to the property of the plate being made of a glass material having a high brittleness. In addition, although two cross cuttings are required to make a plurality of optical filters 20, two cross cuttings may easily damage the optical filter 20 in a situation in which support conditions are poor as described above.

In addition, since the cut surface of the optical filter 20 is very rough after being cut by the optical filter 20, the mirror surface processing of the optical filter 20 requires a multi-step polishing process. In addition, although the process of repositioning the cut portions of the filter assembly after one cut is necessary when making the plurality of optical filters 20, a cumbersome process of temporarily bonding the cut portions of the filter assembly to maintain the repositioning state. Should go through. Therefore, the above-described optical filter manufacturing method has a problem in that the thickness of the light transmissive plates 11 and 12 is not suitable or the size of the optical filter 20 is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to provide a method for manufacturing an optical filter for multiplexing / demultiplexing, which may be suitable for mass production, miniaturization, and low cost of an optical filter.

In order to achieve the above object, a method for manufacturing an optical filter for multiplexing / demultiplexing according to the present invention includes providing two or more light-transmissive plates, and forming and bonding a filter layer that transmits only light of a corresponding wavelength therebetween to form a filter assembly. Forming a; And cutting V grooves on at least one surface parallel to the filter layer in the filter assembly so that a plurality of optical filters are continuously formed in a predetermined form by using cutting edges each having a tapered shape of 45 degrees along the rotation axis direction on both sides. It includes; step.

According to the present invention, it is possible to precisely cut while minimizing damage in a state in which the filter assembly is firmly supported. In addition, since the V grooves are processed in the filter assembly to manufacture an optical filter, the surface roughness of the cutting surface of the optical filter may be good. Accordingly, the polishing process for mirror processing of the optical filter can be simplified. In addition, after processing the V grooves on one surface of the filter assembly, the process of repositioning the V groove processing portions and the process of temporarily bonding the V groove processing portions may be omitted. Therefore, since the manufacturing of the optical filter is facilitated, it may be advantageous for mass production of the optical filter, but also for miniaturizing and manufacturing the optical filter.

According to the present invention, by applying the most reproducible thin film coating technology of the filter manufacturing technology, it is advantageous to the performance and it is possible to lower the cost compared to PLC-based optical filters such as Echelle filter. In addition, it is possible to maintain the performance of the filter as it is, regardless of the size, it is advantageous to miniaturize the filter, and because it is a prism shape, it is easy to mount the surface can be applied to the two-way optical transmission and reception technology that transmits two or more wavelengths to a single optical fiber.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 and 3 are perspective views illustrating a method of manufacturing an optical filter for multiplexing / demultiplexing according to a first embodiment of the present invention. 4 is a cross-sectional view illustrating an optical filter manufactured by the manufacturing method illustrated in FIGS. 2 and 3.

As shown in Figure 2 and 3, the manufacturing method of the optical filter for multiplexing / demultiplexing is as follows.

First, two or more light transmissive plates are provided, and a filter layer for transmitting only light of a corresponding wavelength is formed between them and bonded to form a filter assembly. For example, when the optical filter 100 is manufactured in the form of a two-channel hexahedral filter as shown in FIG. 4, a pair of light transmitting plates 111 and 112 having the same thickness are provided. Then, the filter layer 113 that transmits only the light of the wavelength is formed on one light-transmissive plate 111. Subsequently, the other transparent plate 112 is bonded to the filter layer 113 with an adhesive such as epoxy to form the filter assembly 110.

After the filter assembly 110 is formed in this way, the optical filter 100 is set in a set shape, for example, a two-channel hexahedral filter, by using a cutting edge 31 having a curved shape tapered at 45 degrees along the rotation axis direction on both sides. In order to form a plurality of continuous in the form, in the filter assembly 110, V grooves 114 are respectively processed on both sides parallel to the filter layer 113. At this time, the V-groove 114 is symmetrical with respect to the filter layer 113, and each bottom part is located in the center of the filter layer 113, and is processed so that it may be continuously connected to each other. Subsequently, when the plurality of continuous optical filters 100 are separated, a plurality of optical filters 100 having a hexahedral filter form of two channels may be manufactured.

The optical filter 100 in the form of a 2-channel hexahedral filter may be operated as shown in FIG. 4. When two optical signals having different wavelengths λ1 and λ2 are multiplexed into the optical filter 100, only an optical signal having the wavelength λ2 passes through the filter layer 113 and is output from the optical filter 100. The optical signal of the remaining wavelength λ1 is reflected by the filter layer 113 at an angle of 90 degrees and output to the optical filter 100. Accordingly, the two multiplexed optical signals can be demultiplexed. Meanwhile, when two optical signals having different wavelengths λ1 and λ2 are propagated in the opposite direction to enter the optical filter 100, the two optical signals may be multiplexed.

By the optical filter manufacturing method as described above, since the V-groove 114 is processed on a wide surface parallel to the filter layer 113 in the filter assembly 110, the damage to the state in which the filter assembly 110 is firmly supported. Precise cutting with minimal Further, since the V grooves 114 are processed in the filter assembly 110 by the cutting edge 31 having the inclined surface of 45 degrees on both sides, the surface roughness of the cutting surface of the optical filter 100 may be good. Accordingly, the polishing process for mirror processing of the optical filter 100 can be simplified.

In addition, after processing the V-groove 114 on one surface of the filter assembly 110, since the V-grooved parts have a continuous form without being separated, the process of relocating the V-groove parts and the V-groove parts temporarily The bonding process can be omitted. Since the manufacturing of the optical filter 100 is facilitated as described above, it may be advantageous to mass-produce the optical filter 100 while also miniaturizing the optical filter 100.

Meanwhile, in manufacturing the optical filter of FIG. 4, a method of processing V grooves in the filter assembly will be described in detail with reference to FIGS. 5A to 5E.

First, as shown in FIG. 5A, before processing the V grooves 114 in the filter assembly 110, the support 32 may be installed in the filter assembly 110. The support 32 is for reinforcing cutting of the filter assembly 110 in the processing of the V-grooves 114. That is, in the process of processing the V grooves 114 in the filter assembly 110, there is a possibility that the filter layer junction of the filter assembly 110 is broken by cutting resistance, and the support 32 is the filter layer during the processing of the V grooves 114. It is possible to minimize the breakage of the joint. If the support 32 is in a horizontal state, it may be installed on both sides parallel to the longitudinal direction of the V-groove 114 to be processed in the filter assembly 110. Prior to the installation of the support 32, both sides of the upper end of the filter assembly 110 may be inclined by the cutting edge 31.

Subsequently, as shown in FIG. 5B, after the cutting edge 31 is positioned on the upper surface of the filter assembly 110, the horizontal and orthogonal to the axis of rotation of the cutting edge 31 is rotated in the state in which the cutting edge 31 is rotated. The V groove 114 is processed on the upper surface of the filter assembly 110 while moving in the vertical direction. At this time, the V-groove 114 is processed so that the bottom of the V-groove 114 is located at the center of the filter layer 113. After that, the V-groove 114 is repeatedly processed while moving the cutting edge 31 at a movement interval set in the rotation axis direction. At this time, the movement interval of the cutting edge 31 is set so that the V-grooves 114 are continuously connected to each other.

Subsequently, as shown in FIG. 5C, the fixing plate 33 and the processed V groove 114 are temporarily fixed to temporarily fix the upper surface of the filter assembly 110 on which the V grooves 114 are processed. Temporary fixing member 34 may be provided between the holes. The temporary fixing member 34 may be made of a paraffinic material.

By the temporary fixing member 34, the filter assembly 110 can be fixed in close contact with the fixing plate 33, thereby being resistant to cutting resistance during the processing of the V grooves 114 with respect to the bottom surface of the filter assembly 110. . In addition, since the V-groove 114 can be protected by the temporary fixing member 34, processing is possible even if the light transmissive plates 111 and 112 are very thin. Accordingly, it may be advantageous to miniaturize and manufacture the optical filter 100.

Subsequently, as shown in FIG. 5D, the bottom surface of the filter assembly 110 is positioned upward, and then the V grooves 114 are processed in the bottom surface of the filter assembly 110 in the same manner as shown in FIG. 5B. . In this case, the V grooves 114 are processed on the bottom surface of the filter assembly 110 to be symmetrical with the V grooves 114 processed on the top surface of the filter assembly 110 based on the filter layer 113.

Thereafter, when the temporary fixing member 34 is removed by heat or a dissolving agent, as shown in FIG. 5E, a plurality of optical filters 100 in the form of a two-channel hexahedral filter can be manufactured. Thereafter, the cutting surface of the optical filter 100 may be polished or polished by performing a polishing or lapping process. In this case, since the cutting surface of the optical filter 100 has better surface roughness characteristics than the cutting surface of a conventional file saw, the polishing process may be much simpler. Thereafter, the antireflection coating may be performed on the optical filter 100 to have a low reflection characteristic.

On the other hand, as shown in Figure 6, by connecting a plurality of cutting edges 31 along the rotation axis direction, a plurality of V grooves 114 may be simultaneously processed in the filter assembly 110. In this case, the optical filter 100 can be manufactured more quickly and can be advantageous for mass production of the optical filter 100.

7 is a perspective view illustrating a method of manufacturing an optical filter for multiplexing / demultiplexing according to a second embodiment of the present invention. 8 is a cross-sectional view showing an optical filter manufactured by the manufacturing method shown in FIG.

Referring to FIG. 7, three or more light transmissive plates are provided, and a filter layer for transmitting only light having a corresponding wavelength therebetween is formed and bonded to form a filter assembly therebetween. For example, when the optical filter 200 is manufactured in the form of a four-channel hexahedral filter, as shown in FIG. 8, four light transmitting plates 211, 212, 213, and 214 having the same thickness are provided, and corresponding to each of the 211, 212, 213, and 214. Filter layers 215, 216, 217 that transmit only light of wavelengths are formed.

Then, the filter assembly 210 to form a plurality of optical filters 200 continuously in the form of a four-channel hexahedral filter by using a cutting edge 31 having a curved shape of 45 degrees in each direction along the rotation axis direction on both sides. The V grooves 218 are machined on both sides parallel to the filter layers 215, 216, 217, respectively. At this time, the method for processing the V-groove 218 in the filter assembly 210 may be made by applying the method according to the above-described embodiment.

The optical filter 200 of the four-channel hexahedral filter manufactured as described above is demultiplexed when four optical signals having different wavelengths λ 1, λ 2, λ 3, and λ 4 are incident as shown in FIG. 8. Enable output. In this case, three optical signals and one optical signal among the four optical signals output from the optical filter 200 may have different advancing directions. Meanwhile, when four optical signals having different wavelengths λ 1, λ 2, λ 3, and λ 4 propagate in the opposite directions and enter the optical filter 200, the four optical signals may be multiplexed.

9 is a perspective view illustrating a method of manufacturing an optical filter for multiplexing / demultiplexing according to a third embodiment of the present invention. 10 is a cross-sectional view showing an optical filter manufactured by the manufacturing method shown in FIG.

Referring to FIG. 9, the filter assembly 310 is formed in the same manner as in the embodiment shown in FIG. 7. After the filter assembly 310 is formed, the optical filter 300 is continuously formed in the form of a four-channel wedge filter by using a cutting edge 31 having a curved shape tapered at 45 degrees along the rotation axis direction on both sides. In order to form a large number, the V-groove 318 is processed on one surface parallel to the filter layers 215, 216, 217 in the filter assembly 310.

The optical filter 300 of the four-channel wedge filter manufactured as described above is demultiplexed when four optical signals having different wavelengths λ1, λ2, λ3, λ4 are input as shown in FIG. 10. Enable output. At this time, the optical signals output from the optical filter 300 all proceed in the same direction.

11 is a perspective view illustrating a method of manufacturing an optical filter for multiplexing / demultiplexing according to a fourth embodiment of the present invention. 12 is a cross-sectional view showing an optical filter manufactured by the manufacturing method shown in FIG.

Referring to FIG. 11, a filter assembly 410 is formed by the method of the embodiment shown in FIG. 7. After the filter assembly 410 is formed as described above, the optical filter 400 of the four channels having the reflective inclined surface 419 is formed by using the cutting edge 31 having a curved shape tapered to each side by 45 degrees along the rotation axis direction. The V grooves 418 are machined on both sides of the filter assembly 410 in parallel with the filter layers 215, 216, 217 so as to form a plurality in succession in the form of a mirror wedge filter.

The optical filter 400 in the form of a four-channel mirror wedge filter having the reflective inclined surface 419 manufactured as described above is four multiplexed with different wavelengths λ1, λ2, λ3, λ4, as shown in FIG. When the optical signals are incident, the light signals may pass through the filter layers 215, 216, 217, or may be reflected by the filter layers 215, 216, 217 and then reflected by the reflective inclined surface 419 to be demultiplexed and output. In this case, two or more optical signals may be output on the same channel. The optical filter 400 described above is advantageous when the offset on the optical path is largely required.

Meanwhile, in the filter assembly 410 of FIG. 11, the thickness of the light transmissive plates is varied to form the filter assembly, and then the V grooves are processed to manufacture the multi-channel optical filter 500, as shown in FIG. 13. It is also possible. At this time, the thickness of the optically transmissive plates, the optical filter 500 to be manufactured to advance the optical signals of different wavelengths (λ1, λ2, λ3, λ4, λ5, λ6) all in different paths, It can be set to adjust the distance of. By adjusting the thickness of the light transmissive plates, the size of the light filter 500 may be reduced.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

1 is a perspective view for explaining a method of manufacturing a prism type optical filter according to a conventional example.

2 and 3 are perspective views illustrating a method for manufacturing an optical filter for multiplexing / demultiplexing according to a first embodiment of the present invention.

4 is a cross-sectional view showing an optical filter manufactured by the manufacturing method shown in FIG. 2 and FIG.

5A to 5E are cross-sectional views for describing a process of processing V grooves in FIG. 3.

FIG. 6 is a cross-sectional view for explaining a process of processing V grooves by a cutting edge according to another example of FIG. 3. FIG.

7 is a cross-sectional view for explaining a method for manufacturing an optical filter for multiplexing / demultiplexing according to a second embodiment of the present invention.

8 is a sectional view showing an optical filter manufactured by the manufacturing method shown in FIG.

9 is a cross-sectional view for explaining a method for manufacturing an optical filter for multiplexing / demultiplexing according to a third embodiment of the present invention.

10 is a cross-sectional view showing an optical filter manufactured by the manufacturing method shown in FIG.

11 is a cross-sectional view for explaining a method for manufacturing an optical filter for multiplexing / demultiplexing according to a fourth embodiment of the present invention.

12 is a cross-sectional view showing an optical filter manufactured by the manufacturing method shown in FIG.

FIG. 13 is a sectional view showing an optical filter manufactured by a modification of the manufacturing method shown in FIG.

<Brief description of the major symbols in the drawings>

31. Cutting edge 32. Support

33. Retaining plate 34. Temporary fastening member

100,200,300,400,500..Optical filter 110..Filter assembly

111,112. Transparent plate 113. Filter layer

114..V Home

Claims (9)

Providing two or more light-transmissive plates, and forming and bonding a filter layer that transmits only light of a corresponding wavelength therebetween to form a filter assembly; And Machining V grooves on at least one surface parallel to the filter layer in the filter assembly to form a plurality of optical filters continuously in a predetermined form by using cutting edges each having a tapered surface shape 45 degrees along the rotation axis direction on both sides; ; Optical filter manufacturing method for multiplexing / demultiplexing comprising a. The method of claim 1, Forming the filter assembly comprises: Providing a pair of the optically transmissive plates and forming the filter layers therebetween and bonding them to form the filter assemblies; Processing the V-grooves is: By using the cutting blade, the V grooves are respectively processed on both sides of the filter assembly in parallel with the filter layer to form a plurality of optical filters in the form of two-channel hexahedral filters, each of which is symmetrical with respect to the filter layer. And a process of processing the V-grooves such that a bottom portion is positioned at the center of the filter layer and continuously connected to each other. 3. The method of claim 2, Prior to machining the V-grooves: The method of manufacturing the optical filter for multiplexing / demultiplexing characterized in that it further comprises the step of installing a support for cutting the reinforcement of the filter assembly in the processing of the V groove. 3. The method of claim 2, Processing the V-grooves is: After the V groove is processed on one surface parallel to the filter layer in the filter assembly, a process of installing a temporary fixing member between the fixing plate and the processed V grooves to temporarily fix one surface of the processed filter assembly to the fixing plate. Optical filter manufacturing method for multiplexing / demultiplexing characterized in that it further comprises. 3. The method of claim 2, The plurality of cutting edges are connected along the direction of the rotation axis, and the plurality of V-grooves are processed simultaneously by a plurality, characterized in that the manufacturing method for multiplexing / demultiplexing. The method of claim 1, Forming the filter assembly comprises: Comprising three or more light-transmissive plates, and forming a filter layer for transmitting only the light of a corresponding wavelength between each of them to form a filter assembly, Processing the V-grooves is: Manufacturing the optical filter for multiplexing / demultiplexing by using the cutting edge, the process of processing the V groove in the filter assembly to form a plurality of continuous in the form of three-channel or more hexahedral filter. Way. The method of claim 1, Forming the filter assembly comprises: Comprising three or more light-transmissive plates, and forming a filter layer for transmitting only the light of the wavelength of each of them between each other to form the filter assembly, Processing the V-grooves is: Manufacturing the optical filter for multiplexing / demultiplexing by using the cutting edge, comprising the step of processing the V-groove in the filter assembly to form a plurality of continuously in the form of a wedge filter of three or more channels. Way. The method of claim 1, Forming the filter assembly comprises: Comprising three or more light-transmissive plates, and forming a filter layer for transmitting only the light of a corresponding wavelength between each of them to form a filter assembly, Processing the V-grooves is: And processing the V grooves in the filter assembly to form a plurality of the optical filters continuously in the form of a mirror wedge filter having three or more channels having a reflective inclined surface by using the cutting edge. Method for manufacturing multiplexing optical filter. The method of claim 8, Forming the filter assembly comprises: For the multiplexing / demultiplexing, the optical filter sets the thickness of the light transmissive plates so that the optical signals of different wavelengths can all travel in different paths and adjust the distance between the optical output terminal or the optical input terminal. Optical filter manufacturing method.

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