Manufacturing method of CWDM-BLOCK with interval of 250 [mu] m based on ultrathin optical filter

Abstract

The invention relates to the technical field of wavelength division multiplexers, and discloses a 250 [mu] m spacing CWDM-BLOCK manufacturing method based on ultrathin optical filters, and the method comprises the steps: designing and preparing CWDM optical filters, and carrying out the cutting and testing, so as to enable the four optical filters to be arranged in a row in advance; a micro lens is designed and prepared, the spherical surface is plated with an air antireflection film, and the plane end is plated with an adhesive antireflection film; the method comprises the following steps: setting and preparing a glass substrate, polishing two surfaces of the glass substrate, and manufacturing alignment positioning marks on the two surfaces of the glass substrate according to set size intervals; plating a high-reflection film with a gap on one surface of the glass substrate; performing CWDM optical filter group surface mounting on the surface, which is not plated with the high-reflection film, of the glass substrate; pasting a micro lens on the surface plated with the high-reflection film; and cutting is carried out from the position of the alignment positioning mark to obtain a complete CWDM-BLOCK with a collimating lens and a distance of 250 [mu] m. According to the method, mass production and manufacturing of 250-micron CWDM-BLOCK can be achieved, the method is suitable for assembling operation through automatic equipment, the assembling and testing efficiency is greatly improved, and the method is suitable for large-scale manufacturing.

Description

Technical Field

[0001] The invention relates to the technical field of wavelength division multiplexers, and in particular to a method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter. Background Art

[0002] Miniaturization and integration are the development direction of optical devices. As a miniature wavelength division multiplexer, CWDM-BLOCK products have compact size and good performance indicators, and are widely used in multi-channel high-speed optical modules. As the speed of optical modules increases, the number of channels increases, and more and more optical devices are used, the size of optical devices is objectively required to be further reduced, while realizing more functions and making maximum use of the limited space inside the optical module. CWDM-BLOCK with a spacing of 250um appears to meet this demand.

[0003] like Figure 1 As shown, the existing Z-BLOCK device mainly consists of two parts, one is a coated glass block, and the other is a filter group of four pieces closely together; the parallelism of the two surfaces of the coated glass block is in the second level, one side is coated with a high-reflection film and an anti-reflection film at a specified position, and the other side is polished; the filter group is mounted on the polished surface of the prism; when working, a collimated light beam containing four different wavelengths is incident from the AR area of ​​the glass prism, and undergoes multiple refractions and reflections inside the prism, and finally outputs four light beams with equal distances in space at the end face of the filter; in the Z-BLOCK, the θ angle of the glass prism determines the thickness of the entire device, and the larger the θ angle, the smaller the thickness of the glass block and the smaller the overall size; the larger the pitch Pitch of the output light beam, the larger the width, and the size of the pitch is determined by the pitch of the corresponding detector or laser behind the filter; commonly used angle values ​​are 8°, 13.5°, etc., and the commonly used pitch value is 750um / 500um, which can be used in both optical transmitting components and optical receiving components.

[0004] BLOCK works under collimated beam. The collimated light of Gaussian beam has a working distance. Beyond this working distance, the spot size rapidly increases and the beam is no longer collimated. Therefore, the size of the beam spot is closely related to the collimation distance. The maximum size of the spot is limited by the pitch value of BLOCK. Usually, the larger the spot, the longer the collimation distance, and the more suitable it is for large-pitch BLOCK. When the collimated beam passes through the filter, it has a certain tilt angle, so that the filter aperture is smaller than the surface size of the filter. The blocked size is proportional to the thickness of the θ glue and the substrate of the filter. The thicker the filter, the larger the θ angle, the larger the blocked size, and the smaller the filter aperture. When the product is used, it is hoped that the aperture is as large as possible, while the structural size is as small as possible. In the process of filter mounting, the smaller the filter size, the higher the control accuracy requirements during the arrangement process, and the lower the efficiency and yield in the operation; at the same time, the smaller the filter size, the higher the requirements for patch positioning accuracy, and the corresponding efficiency is also lower.

[0005] For blocks with a spacing of 500um and 750um, the spot size of the collimator, the thickness of the filter, and the size and accuracy of the prism coating area can meet the requirements. However, for blocks with a spacing of 250um, all conventional parameters cannot meet the requirements. The specific difficulties are as follows:

[0006] 1. The collimator spot needs to be around 100um to meet the aperture requirements; the collimator that produces a 100um spot uses a C lens with a curvature radius of about 0.65mm and a diameter of The production process of a micro lens with a thickness of about 1.0 mm is very difficult and costly.

[0007] 2. The 0.5mm substrate of the filter is too thick, and the thickness of the filter substrate needs to be further reduced to meet the requirements of the light aperture. At present, it is very difficult to plate a large-angle CWDM filter below 0.5mm.

[0008] 3. For the 250um pitch BLOCK, the overall size of the glass prism is relatively small, about 1x1x1.4mm. The method of using a fixture as a mask and coating on a long glass strip not only fails to meet the 0.1mm transition zone tolerance accuracy requirement, but also greatly increases the difficulty of operation.

[0009] 4. When mounting the 250um BLOCK filter, the positioning method based on the outer wheel has a large accuracy deviation, resulting in excessive performance indicators such as insertion loss / crosstalk and low yield. Summary of the invention

[0010] In order to solve the difficulties in realizing the 250um BLOCK technology, the present invention provides a method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter, which can realize the mass production of 250um CWDM-BLOCK, is suitable for assembly operations using automated equipment, greatly improves the efficiency of assembly and testing, and is suitable for large-scale manufacturing.

[0011] The present invention provides a method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter, comprising:

[0012] S1. Design and prepare CWDM filters, whose thickness is 0.3 mm ± a set value, and cut and test the CWDM filters to pre-arrange four wavelength qualified filters in a row to form a CWDM filter set;

[0013] S2. Design and prepare a microlens with a thickness of 0.3 mm ± a set value. The spherical surface of the microlens is coated with an anti-reflection film for air, and the flat end is coated with an anti-reflection film for glue;

[0014] S3, setting and preparing a glass substrate with a thickness of 1 mm ± a set value and a size of 40 x 40 mm, wherein both sides of the glass substrate are polished, and alignment marks are accurately made on both sides of the glass substrate according to a set size interval by using a photolithography process;

[0015] S4, coating a high-reflective film with gaps on one surface of the glass substrate by using a masking method;

[0016] S5, on the side of the glass substrate not coated with a high-reflection film, CWDM filter sets are pasted at the positions surrounded by the four alignment positioning marks; on the side coated with a high-reflection film, microlenses are pasted at the positions corresponding to each CWDM filter set;

[0017] S6. Cut from the alignment mark position to obtain a complete CWDM-BLOCK with a 250 um spacing and a collimating lens.

[0018] Furthermore, in step S1, the CWDM filter adopts a non-regular film system design according to the principle mechanism of stress generation, adjusts the ratio of the two materials, and cooperates with the corresponding film thickness control algorithm to prepare an ultra-thin CWDM filter with a thickness of 0.3mm±set value, and its maximum angle can reach 13 degrees.

[0019] Furthermore, in step S2, the microlens is prepared by etching a microlens with a diameter of 200 um on a quartz glass or silicon substrate of 0.3 mm to 0.5 mm using a semiconductor etching process to generate a collimated light beam with a spot size of 100 um ± a set value.

[0020] Furthermore, in step S3, the alignment deviation of the alignment mark of the glass substrate on the front and back surfaces is on the order of um.

[0021] Furthermore, in step S4, the transition area of ​​the high-reflection film is less than 30 um, so as to significantly reduce the transition area and thus increase the light aperture.

[0022] Furthermore, in step S5, the microlens is located at the incident port of the CWDM-BLOCK, and the CWDM filter set and the microlens are both mounted using a mounting device and fixed using UV glue.

[0023] Furthermore, before step S6, the method further includes:

[0024] After the patch is completed, an online test is performed at the wafer level to identify products with poor placement.

[0025] The present invention also provides a 250um spacing CWDM-BLOCK, which adopts the manufacturing method of the 250um spacing CWDM-BLOCK based on the ultra-thin filter as described above, and has a microlens prepared by an etching process at the incident port position of the coated glass prism. When in use, the incident port is directly coupled to the optical fiber; at the exit port position of the coated glass prism are 4 filters connected end to end, the filter size along the pitch direction is 0.25mm, and the size in the direction perpendicular to the pitch is 0.6mm±set value, and the coated prism is in the form of a rectangular parallelepiped.

[0026] The beneficial effects of the present invention are:

[0027] The present invention has a microlens prepared by etching process at the incident port position of the coated glass prism. When in use, the incident port is directly coupled with the optical fiber, and the output port position is 4 filters connected end to end. The filter is a large-angle ultra-thin CWDM filter with a thickness of 0.3mm and a maximum angle of 13 degrees. The microlens is used to generate a collimated light beam with a light spot of about 100um, so that the BLOCK product with the lens is directly aligned and coupled with the optical fiber when in use, avoiding loss and crosstalk caused by incompatible light spots; the BLOCK with a spacing of 250um uses relatively small material sizes and requires relatively high precision, which is suitable for assembly operations using automated equipment. Compared with manual assembly, the efficiency of assembly and testing is greatly improved, and it is suitable for large-scale manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural diagram of BLOCK in the background technology of the present invention.

[0029] Figure 2 This is a schematic diagram of a BLOCK structure with a spacing of 250 um according to an embodiment of the present invention.

[0030] Figure 3 The figure is a schematic diagram of a method flow according to an embodiment of the present invention.

[0031] Figure 4 FIG. 4 is a schematic diagram of CWDM filter arrangement according to an embodiment of the present invention.

[0032] Figure 5 FIG. 4 is a schematic diagram of a manufacturing structure of a microlens according to an embodiment of the present invention.

[0033] Figure 6 FIG. 1 is a schematic diagram of an alignment mark according to an embodiment of the present invention.

[0034] Figure 7 FIG. 4 is a schematic diagram of a coating according to an embodiment of the present invention.

[0035] Figure 8 FIG. 4 is a schematic diagram of a CWDM filter patch according to an embodiment of the present invention.

[0036] Fig. 9 FIG. 4 is a schematic diagram of a microlens patch according to an embodiment of the present invention.

[0037] Fig.10 It is a schematic diagram of the CWDM filter portion after mounting and cutting according to an embodiment of the present invention.

[0038] Fig.11 FIG. 4 is a schematic diagram of a microlens portion after mounting and cutting according to an embodiment of the present invention.

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0041] With regard to the difficulty in realizing the 250um BLOCK technology, the present invention provides a technical solution that can realize the mass production of 250um CWDM-BLOCK.

[0042] Conventional CWDM filters use a regular film system design, which has large stress between film layers and cannot be produced on glass substrates with a thickness of less than 0.5mm. According to the principle mechanism of stress generation, a non-regular film system design is adopted, the ratio of the two materials is adjusted, and the corresponding film thickness control algorithm is used to produce a large-angle ultra-thin CWDM filter with a thickness of 0.3mm, and the maximum angle can reach 13 degrees.

[0043] To produce a small spot collimated beam, a small diameter lens is required. Conventional processes are very advantageous for preparing lenses with a diameter greater than 1mm. However, for preparing tiny lenses with a diameter less than 0.75mm, the process method of semiconductor etching is advantageous. The present invention uses a quartz glass or silicon substrate of 0.3mm to 0.5mm to etch and manufacture a microlens with a diameter of 200um, which is used to produce a collimated beam with a spot of about 100um.

[0044] The 250um pitch BLOCK uses an incident angle of 8 to 13 degrees, and the thickness of the coated glass substrate is about 1mm. Substrates of this thickness can be cut using equipment for cutting semiconductor wafers. The corresponding coated glass prisms can also be prepared using semiconductor process methods, which is efficient and low-cost.

[0045] Based on this, the present invention proposes a method for preparing a 250um spacing BLOCK with a collimating lens. The product structure is as follows: Figure 2 As shown, the incident port of the coated glass prism is provided with a microlens prepared by etching process. When in use, the incident port can be directly coupled with the optical fiber. The exit port on the right is 4 filters connected end to end. The filter size along the pitch direction is 0.25mm, and the size perpendicular to the pitch is about 0.6mm. The coated prism is in the form of a rectangular parallelepiped, which is convenient for cutting and processing.

[0046] The production and process of CWDM-BLOCK in the traditional way are briefly described as follows:

[0047] 1. Production of coated prism

[0048] 1.1 Make a long strip of rhombic prism according to the required angle θ;

[0049] 1.2 Make precise coating fixtures according to size requirements, and coat different films in different areas through two coating processes;

[0050] 1.3 The positioning accuracy of the AR area and the size of the transition area between HR and AR are key dimensions that affect the size of the clear aperture; the typical accuracy of these two dimensions is 0.1mm or 0.15mm.

[0051] 2. Fabrication of filter sets

[0052] 2.1 CWDM optical films of different wavelengths are deposited on the required large glass substrate. Usually the thickness of the glass substrate is greater than 0.55mm.

[0053] 2.2 Cut and test the coated large pieces to select qualified filters.

[0054] 2.3 Arrange four filters of different wavelengths in a group, with the filters close to each other.

[0055] 3. Filter mounting test

[0056] 3.1 Place the coated prism and filter set on the predetermined fixture;

[0057] 3.1 Carry / transfer the filter set as a whole, and then mount it on the designated position of the polished surface of the coated prism. Usually the relative positioning accuracy is about 20um; UV glue is used to bond the filter set and the coated prism;

[0058] 3.3 Test the finished BLOCKs one by one.

[0059] like Figure 3 As shown, the present invention provides a method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter, that is, the manufacturing process of the BLOCK product is described as follows:

[0060] S1. Design and prepare a low-stress CWDM filter with a thickness of about 0.3 mm (0.3 mm ± set value), cut and test the filter; arrange the qualified filters of four wavelengths in a row in advance, such as Figure 4 shown.

[0061] S2. Design and prepare a micro lens with a thickness of about 0.3mm (0.3mm±set value). When matched with the optical fiber, it can produce a collimated beam with a spot size of about 100um. The spherical surface is coated with an anti-reflection film for air, and the flat end is coated with an anti-reflection film for glue, such as Figure 5 shown.

[0062] S3. Design and prepare a glass substrate with a thickness of about 1mm (1mm±set value) and a size of 40x40mm. The two sides of the glass substrate are polished, and the parallelism of the two sides is in the second level. On the two sides of the glass substrate, according to the designed size interval, use the photolithography process to accurately make alignment and positioning marks on the two sides of the glass substrate. The shape and distribution of the marks are as follows: Figure 6 As shown, the alignment deviation of the mark on the front and back surfaces is on the order of um.

[0063] S4. On one side of the glass substrate, a high-reflective film with gaps is plated using a masking method, such as Figure 7 As shown (the grid area in the figure is coated with a high-reflection film, and the white strip area is not coated); the transition area of ​​the coating can be less than 30um, which greatly reduces the transition area and thus increases the aperture.

[0064] S5. On the surface of the glass substrate without reflective film, according to the position of the mark point (alignment mark), use the patch equipment to place the arranged CWDM filter patch at the corresponding position and fix it with UV glue. The picture of the patch is as follows: Figure 8 As shown; on the side coated with high reflection film, the micro lens is mounted according to the position of the mark point. The micro lens is also fixed with UV glue. The completed mounting is as shown Fig. 9 shown.

[0065] S6. After the mounting is completed, wafer-level online testing can be performed to identify products with poor mounting. This test is a wafer-level test with high test efficiency.

[0066] After the test is completed, the cutting is carried out from the mark position. After the cutting, each small particle is a complete BLOCK product with a 250um spacing and a collimating lens. Fig.10 , 11 shown.

[0067] The BLOCK product with lens is directly aligned and coupled with the optical fiber during use, avoiding loss and crosstalk caused by mismatched light spots. The 250um pitch BLOCK uses relatively small materials and requires relatively high precision, making it suitable for assembly using automated equipment. Compared with manual assembly, it greatly improves the efficiency of assembly and testing and is suitable for large-scale manufacturing.

[0068] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0069] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter, characterized in that: include: S1. Design and prepare a CWDM filter with a thickness of 0.3 mm ± a set value, and cut and test the CWDM filter to pre-arrange four wavelength qualified filters in a row to form a CWDM filter set; S2. Design and prepare a microlens with a thickness of 0.3 mm ± a set value. The spherical surface of the microlens is coated with an anti-reflection film for air, and the flat end is coated with an anti-reflection film for glue; S3, setting and preparing a glass substrate with a thickness of 1 mm ± a set value and a size of 40 x 40 mm, wherein both sides of the glass substrate are polished, and alignment marks are accurately made on both sides of the glass substrate according to a set size interval by using a photolithography process; S4, coating a high-reflective film with gaps on one surface of the glass substrate by using a masking method; S5, performing CWDM filter set patching on the surface of the glass substrate not coated with a high-reflection film at the positions surrounded by the four alignment positioning marks; On the side coated with high reflection film, micro lenses are mounted at the corresponding positions of each CWDM filter group; S6. Cut from the alignment mark position to obtain a complete CWDM-BLOCK with a 250 um spacing and a collimating lens.

2. The method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter according to claim 1, characterized in that: In step S1, the CWDM filter adopts a non-regular film system design according to the principle mechanism of stress generation, adjusts the ratio of the two materials, and cooperates with the corresponding film thickness control algorithm to prepare an ultra-thin CWDM filter with a thickness of 0.3mm±set value, and its maximum angle can reach 13 degrees.

3. The method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter according to claim 1, characterized in that: In step S2, the microlens is prepared by etching a microlens with a diameter of 200 um on a quartz glass or silicon substrate of 0.3 mm to 0.5 mm using a semiconductor etching process to generate a collimated light beam with a spot size of 100 um ± a set value.

4. The method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter according to claim 1, characterized in that: In the step S3, the alignment deviation of the alignment marks of the glass substrate on the front and back surfaces is on the order of um.

5. The method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter according to claim 1, characterized in that: In the step S4, the transition area of ​​the high-reflection film is less than 30 um, so as to significantly reduce the transition area and thus increase the light aperture.

6. The method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter according to claim 1, characterized in that: In the step S5, the microlens is located at the incident port of the CWDM-BLOCK, and the CWDM filter set and the microlens are both mounted using a mounting device and fixed using UV glue.

7. The method for manufacturing a 250um spacing CWDM-BLOCK based on an ultra-thin filter according to claim 1, characterized in that: Before step S6, the method further includes: After the patch is completed, an online test is performed at the wafer level to identify products with poor placement.

8. A 250um spacing CWDM-BLOCK, characterized in that: A method for manufacturing a 250um pitch CWDM-BLOCK based on an ultra-thin filter as described in any one of claims 1 to 7 is adopted, wherein a microlens prepared by an etching process is provided at the incident port position of the coated glass prism, and when in use, the incident port is directly coupled to the optical fiber; at the exit port position of the coated glass prism are 4 filters connected end to end, the filter size along the pitch direction is 0.25mm, and the size in the direction perpendicular to the pitch is 0.6mm±the set value, and the coated prism is in the form of a rectangular parallelepiped.

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