Filter plate assembly and narrow-band filter

Abstract

The filter assembly comprises a filter support and a filter, the filter support comprises a bottom and side plates vertically upward from two opposite sides of the bottom, a U-shaped structure with an upward opening is enclosed by the bottom and the side plates on the two sides, the filter is welded on the inner bottom surface of a U-shaped groove of the filter support, and the filter is welded on the inner bottom surface of the U-shaped groove of the filter support. An optical fiber collimator of the narrow-band filter is welded on a collimator support, the collimator support and a filter support are welded on the upper surface of a welding bottom plate, the welding bottom plate is welded on a semiconductor cooler, and the semiconductor cooler is welded on a bottom plate in a tube shell. In the narrow-band filter package, the collimator bracket, the filter bracket and the welding bottom plate, the optical fiber collimator and the collimator bracket, and the filter and the filter bracket are fixed in a welding manner, so that the influence caused by different expansion coefficients of materials in the package can be reduced, and the reliability of the package is effectively improved; and the influence of external acting force and temperature change is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of optical communication and photonics, and specifically relates to a filter assembly and a narrowband filter. BACKGROUND

[0002] A narrowband filter is an optical device that selectively passes optical signals of specific frequencies and suppresses other frequencies through resonance cavities or interference effects. Narrowband filters are widely used in optical fiber communication, spectral analysis, and laser systems.

[0003] However, the existing filter packaging uses glue to fix each component inside, which is easily affected by external temperature, thereby reducing performance indicators. Glued components also have the risk of falling off when subjected to external impact or vibration.

[0004] Invention patent application No. CN112485864A discloses a flexible and simple design of an optical fiber bandpass filter, which includes two optical fiber collimators, two collimator supports, two filter pieces, two filter piece supports, a device bottom shell, and a device cover plate. The collimator supports are fixed to the device bottom shell, the optical fiber collimators are fixed to the collimator supports, the filter pieces are fixed to the filter piece supports, and the device cover plate is fixed to the device bottom shell for device sealing. In this application, the connection between the filter support and the device bottom shell and the filter piece is fixed by glue bonding, and the collimator is fixed to the collimator support and connected to the two opposite side walls of the device bottom shell.

[0005] The above-mentioned filter packaging internal component mounting method has the problem of insufficient reliability, that is, it is easily affected by external environmental temperature and the device fixing method is not firm. When using the traditional packaging method of filling the optical fiber tube with glue, the packaging airtightness of the optical fiber collimator is insufficient, which cannot adapt to the application in complex environments. In the scheme of fixing the filter piece support to the device bottom shell and connecting the collimator support to the two opposite side walls of the device bottom shell, the internal optical path of the filter packaging is easily affected by the deformation of the device bottom shell. If the flatness of the installation plane of the filter packaging is insufficient, the device bottom shell will deform when the device is tightened, thereby reducing the coupling efficiency. SUMMARY

[0006] The technical problem to be solved by the utility model is how to improve the reliability of the installation of the internal components of the filter packaging.

[0007] The utility model discloses a filter piece subassembly, including filter piece support (8) and filter piece (7), filter piece support (8) includes bottom and the vertical side plate of opposite two sides from bottom, and bottom and both sides side plate jointly enclose a open -up U type structure to the U type structure of the bottom of filter piece (7) welding in the U groove of filter piece support (8) is welded in the inner bottom surface of the U groove of filter piece support (8).

[0008] As a further optimization technical scheme, filter piece (7) and the spacing between the two side plates of filter piece support (8).

[0009] As a further optimization technical scheme, the U groove top of filter piece support (8) is higher than filter piece (7).

[0010] The utility model discloses a narrow band filter still further provides a kind of, including: shell (1), semiconductor refrigerator (2), welding bottom plate (3), collimator subassembly, shell cover plate (6), above-mentioned filter piece subassembly, shell (1) both sides are provided with optical fiber tube (11), shell cover plate (6) is covered on shell (1) top, collimator subassembly and filter piece support (8) are welded on welding bottom plate (3) upper surface, welding bottom plate (3) is welded on semiconductor refrigerator (2), semiconductor refrigerator (2) is welded on the bottom plate (12) in shell (1).

[0011] As a further optimization technical scheme, the narrow band filter further includes: temperature sensor (9), temperature sensor (9) is welded on welding bottom plate (3) near filter piece subassembly.

[0012] As a further optimization technical scheme, at least one injection hole (111) is set up above optical fiber tube (11), for injecting solder, to fill optical fiber tube (11).

[0013] As a further optimization technical scheme, the shell (1) further includes bottom plate (12), ring frame (13), lead pin (14) and insulator (15), wherein optical fiber tube (11) is respectively arranged on opposite sides of ring frame (13), bottom plate (12) is fixed to the bottom of ring frame (13), lead pin (14) extends out of the front panel of ring frame (13), and insulator (15) is arranged between lead pin (14) and ring frame (13).

[0014] As a further optimization technical scheme, collimator subassembly includes collimator support (4) and optical fiber collimator (5), and the optical fiber collimator (5) is welded on the collimator support (4), and the collimator support (4) bottom is welded on the upper surface of the welding bottom plate (3).

[0015] As a further optimization technical scheme, the gold-plated tube (51) of optical fiber collimator (5) is sleeved in collimator support (4).

[0016] As a further optimization technical scheme, the collimator support (4) is saddle-shaped, comprising a middle circular arc sleeve and a side wall welding plane and a bottom welding plane formed by extending downward and folding from both sides of the circular arc sleeve, and the collimator support (4) is welded and fixed with the front and rear sides of the gold-plated tube (51) of the fiber collimator (5) through the side wall welding plane.

[0017] The utility model discloses the advantages are:

[0018] 1, the utility model discloses a filter plate subassembly, and the filter plate is welded and fixed on the welding bottom plate through the filter plate support, reduces the influence of the different material expansion coefficient, improves the reliability of filter plate installation, and the U-shaped groove bottom height of filter plate support can be designed according to the height of fiber collimator, so that when the filter plate is placed to the upper surface of the U-shaped groove bottom of filter plate support, the filter plate and fiber collimator are at the same center height, guarantee filter performance stability.

[0019] 2, the utility model discloses a narrowband filter, and the collimator support in the package interior is welded and fixed after welding bottom plate, then the fiber collimator is welded and fixed with the collimator support, and the filter plate is welded and fixed on the welding bottom plate through the filter plate support, all adopt welding mode fixed, and the light path in the package interior of narrowband filter is all placed on the welding bottom plate, can reduce the influence of the different material expansion coefficient of package, can effectively improve the reliability of package, and is not easily affected by external force and temperature change.

[0020] 3, compared with the fiber tube filled with traditional glue, solder filling can effectively improve the airtightness level of package, and parallel sealing is used to seal the shell cover plate and the shell, to further improve the airtightness level of package. DRAWINGS

[0021] Figure 1 It is the whole machine explosion map of the narrowband filter of the utility model embodiment, wherein the collimator support and the fiber collimator have been assembled;

[0022] Figure 2 It is the whole machine explosion map of the narrowband filter of the utility model embodiment, wherein the collimator support and the fiber collimator have not been assembled;

[0023] Figure 3 It is the welding point position drawing of the narrowband filter of the utility model embodiment. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described in combination with the embodiments of the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0025] It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. The drawings provided in the following embodiments only illustrate the basic concept of the utility model in a schematic manner, and only show the components related to the utility model in the drawings, not the components number, shape and size when actually implemented. The actual implementation of each component type, number and proportion can be arbitrarily changed, and the component layout type can also be more complex.

[0026] It should be noted that the direction terms mentioned in the embodiments, such as "up", "down", "front", "back", "left", "right", etc., are only the direction of the drawings, and are not used to limit the protection scope of the disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion to the understanding of the disclosure, the conventional structure or configuration will be omitted.

[0027] The words such as "first", "second", "third" and the like used in the specification and claims are used to modify the corresponding elements, which do not mean that the elements have any sequence, nor represent the sequence of one element and another element or the sequence in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish one element with the same name from another element.

[0028] As shown in Figure 1 and Figure 2 The utility model provides a narrow band filter, include: casing 1, semiconductor refrigerator 2, welding bottom plate 3, collimator support 4, optical fiber collimator 5, casing cover plate 6, filter piece 7, filter piece support 8 and temperature sensor 9.

[0029] Among them, casing 1 includes optical fiber tube 11, bottom plate 12, ring frame 13, lead pin 14 and insulator 15, mainly to internal device and optical path play support, protection and heat conduction effect, wherein optical fiber tube 11 is arranged at the opposite sides of ring frame 13 respectively, to access two side optical fiber collimator 5 respectively, bottom plate 12 is fixed to the bottom of ring frame 13, is used for with other device fixed, lead pin 14 extends the front panel of ring frame 13, and insulator 15 is arranged between lead pin 14 and ring frame 13.

[0030] The semiconductor refrigerator 2 is welded and fixed on the bottom plate 12 in the ring frame 13.

[0031] The welding bottom plate 3 mainly plays a role of fixing and heat conduction in the package and is used as a laser welding backing plate.

[0032] The fiber collimator 5 is an optical device of the package, wherein the fiber collimator 5 on the left side input end provides a light source for the filter package, and the fiber collimator 5 on the right side output end is used for receiving a fixed frequency optical signal, and of course the fiber collimators 5 on the left and right sides can also be interchanged. The collimator support 4 is designed in a saddle shape, the middle arc-shaped sleeve of the collimator support 4 is sleeved with the gold-plated tube 51 of the fiber collimator 5 and leaves a certain amount of excess, and the up and down movement amount of the fiber collimator 5 in the collimator support 4 is set to be between 0.2-0.5mm, and the optimal value is 0.3mm, which is convenient for optical coupling. The collimator support 4 sleeving the fiber collimator 5 is welded on the upper surface of the welding bottom plate 3, and the welding bottom plate 3 is welded on the semiconductor refrigerator 2, so that the semiconductor refrigerator 2 can control the temperature of the filter piece 7, so that the filter piece 7 maintains a relatively stable working temperature. Specifically, the collimator support 4 includes a middle arc-shaped sleeve and a side wall welding plane and a bottom welding plane which are formed by extending and folding downward from both sides of the arc-shaped sleeve, the collimator support 4 is welded and fixed with the front and rear sides of the gold-plated tube 51 of the fiber collimator 5 through the side wall welding plane, and the collimator support 4 is welded and fixed with the welding bottom plate 3 through the bottom welding plane, so that the main part of the gold-plated tube 51 of the fiber collimator 5 is fixed as a whole inside the tube shell 1. Before welding, the gap between the side wall welding plane and the gold-plated tube 51 of the fiber collimator 5 is ensured to be within 50um, which ensures the reliability of welding. The tail fiber of the fiber collimator 5 passes through the fiber tube 11, and at least one injection hole 111 is opened above the fiber tube 11 to inject solder, so as to fill the fiber tube 11 to ensure the airtightness of the package.

[0033] The filter 7 is the core device of the package, and a narrow-band filter is selected to selectively pass light signals of a specific wavelength range. The filter holder 8 is used to fix the filter 7, and the filter holder 8 and the filter 7 are pre-welded together to form a filter assembly. The filter holder 8 includes a bottom and side plates vertically upward from opposite sides of the bottom, and the bottom and the two side plates together form a U-shaped structure with an opening upward. The size of the upper U-shaped groove of the filter holder 8 is designed according to the size of the filter 7. In the embodiment, the length (the extension direction of the fiber collimator 5) of the upper U-shaped groove of the filter holder 8 is 3 mm, the width (transverse and perpendicular to the extension direction of the fiber collimator 5) is set to be between 2.05-2.2 mm, and the optimal value is 2.1 mm, which can meet the assembly of the filter 7 and leave a certain assembly allowance. The height of the upper U-shaped groove of the filter holder 8 is set to be between 2-2.4 mm, and the optimal value is 2.2 mm, which is higher than the filter 7 to facilitate the clamping of the filter holder 8 by the coupling clamp. The height of the bottom of the U-shaped groove of the filter holder 8 is designed according to the height of the fiber collimator 5, so that when the filter 7 is placed on the upper surface of the bottom of the U-shaped groove of the filter holder 8, the filter 7 and the fiber collimator 5 are at the same center height. In the conventional package, glue is used for height adaptation of the filter 7, which is easily affected by the expansion and contraction of the glue at temperature changes, so that the filter 7 and the fiber collimator 5 are no longer at the same center height, resulting in a decline in filter performance. In the embodiment, the filter holder 8 is made of an alloy material, such as Kovar material, which is less affected by temperature changes. The filter 7 is welded to the inner bottom surface of the U-shaped groove of the filter holder 8, and the bottom surface of the filter holder 8 extends outward to form a welding plane, and the bottom of the filter holder 8 is welded to the welding bottom plate 3.

[0034] The temperature sensor 9 is welded to the welding bottom plate 3 near the filter assembly, which is used to detect the real-time temperature of the filter 7 and give feedback.

[0035] The tube cover plate 6 is welded to the upper part of the ring frame 13 in a parallel sealing manner, which cooperates with the tube 1 to protect and seal the internal components of the package, and further improves the air tightness level of the package.

[0036] In the package scheme, laser welding is selected for fixation. Because the solder is less affected by temperature, the stability of the package performance can be greatly improved. In the laser welding process, the selection of the position and sequence of the welding points is particularly important. By setting the welding process and the position of the welding points, the position of the fiber collimator is ensured to be stable, the deviation is reduced, and the optical coupling efficiency is improved.

[0037] Please refer to Figure 3 , wherein A refers to the splicing welding position of the collimator holder 4 and the fiber collimator 5, B refers to the penetration welding position of the collimator holder 4 and the welding bottom plate 3, and C refers to the penetration welding position of the filter holder 8 and the welding bottom plate 3.

[0038] The laser welding in this embodiment is performed by the double-sided welding gun simultaneously on both sides of the device, and mainly includes the following five steps:

[0039] The first step is to perform the penetration welding C of the filter support 8 and the welding base plate 3. A plurality of welding points are arranged, preferably three welding points on each of the front and rear sides of the filter support 8, located on the bottom welding plane of the filter support 8. First, laser welding is performed at the middle position of the bottom welding plane of the filter support 8, and then laser welding is sequentially performed on the left and right sides. The center distance between the welding points needs to be within 850-950 um, and the optimal distance is 900 um.

[0040] The second step is to perform the penetration welding B of the collimator support 4 of the left incident light and the welding base plate 3. A plurality of welding points are arranged, preferably five welding points on each of the front and rear sides, located on the bottom welding plane of the collimator support 4. From left to right, they are left one welding point, left two welding point, middle welding point, right two welding point and right one welding point. The middle welding point needs to be welded first, and then the left one, right one, left two and right two welding points are sequentially welded. This welding sequence can reduce the stress accumulation of the collimator support 4 during welding and reduce the change amount of the performance index in the later period. The center distance between the welding points should be kept within 680-820 um, and the optimal distance is 750 um.

[0041] The third step is to perform the splicing welding A of the collimator support 4 of the left incident light and the fiber collimator 5. A plurality of welding points are arranged, preferably six welding points on each of the front and rear sides of the collimator support 4, divided into two groups of three welding points each. The two groups are located on the side wall welding planes on the left and right sides of the arc-shaped sleeve of the collimator support 4. From left to right, they are left one welding point, left two welding point, left three welding point, right three welding point, right two welding point and right one welding point. First, the left two welding point is welded, and then the right two, left one, right one, left three and right three welding points are sequentially welded. The center distance of the single-sided welding point needs to be greater than or equal to the welding point radius and less than or equal to 1.5 times the welding point radius, and the optimal distance is 1.25 times the welding point radius. For example, the center distance between the left one welding point and the left two welding point is between 1r-1.5r, and the better center distance is 1.25r. The center distance between the left three welding point and the left two welding point is between 1r-1.5r, and the better center distance is 1.25r. r is the radius of the welding point. The right side welding point distance is designed the same. The welding sequence and welding point center distance design is to reduce the displacement of the fiber collimator 5 during laser welding, to ensure the coupling efficiency of the fiber collimator 5 and the filter 7 as much as possible, and to further improve the reliability of the product.

[0042] The fourth step is to perform the penetration welding B of the collimator support 4 of the right incident light and the welding base plate 3, which is the same as the welding method of the second step.

[0043] The fifth step is to splice and weld A the collimator support 4 of the right side outgoing light and the optical fiber collimator 5, and the welding method is the same as the third step.

[0044] The specific implementation method of the filter assembly includes: first, placing the semiconductor refrigerator 2 and the welding base plate 3 on the pipe shell 1 in sequence according to the limiting marks, using the soldering sheet to perform high-temperature vacuum welding on the semiconductor refrigerator 2 and the welding base plate 3, then fixing the temperature sensor 9 on the welding base plate 3 through the soldering sheet, then welding the lead of the semiconductor refrigerator 2 to the internal pin of the pipe shell 1, then communicating the temperature sensor 9 with the internal pin of the welding base plate 3 and the pipe shell 1 through gold wire bonding, then welding and fixing the filter sheet 7 to the filter sheet support 8 through the soldering sheet, then fixing the filter sheet support 8 to the welding base plate 3 through laser welding, and then performing optical coupling; sleeving the collimator support 4 and the optical fiber collimator 5, then fixing the collimator support 4 on the welding base plate 3 through laser welding, then welding the optical fiber collimator 5 to the collimator support 4, and completing the fixation of the optical fiber collimator 5; then filling the optical fiber tube 11 with soldering tin, and finally fixing the pipe shell cover plate 6 on the pipe shell 1 through parallel sealing, and completing the whole packaging process.

[0045] The internal light paths of the packaging are all fixed in a welding mode, the reliability is greatly improved, and the packaging filter loss change is verified to be within 0.3 dB through multiple tests such as a fast temperature change impact test in a temperature range of 0-85 DEG C, a temperature cycle test of-40-85 DEG C, and a mechanical impact test with an acceleration of 4900 m / s 2 , and the packaging filter has high reliability. The packaging air leakage rate of the optical fiber tube 11 filled with soldering tin is less than or equal to 1*10 -9 Pa*m 3 / s, the packaging air tightness of the optical fiber tube 11 filled with glue is only 1*10 -7 Pa*m 3 / s, and the packaging air tightness is also improved.

[0046] The above examples are only used to illustrate the technical solutions of the utility model, and not to limit them; although the utility model has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the utility model embodiments.

Claims

1. A filter assembly comprising a filter holder (8) and a filter (7), characterized in that, The filter holder (8) includes a bottom and two vertically upward side plates from the bottom. The bottom and the two side plates together form a U-shaped structure with the opening facing upward. The filter (7) is welded to the inner bottom surface of the U-shaped groove of the filter holder (8).

2. A filter assembly as claimed in claim 1, wherein There is a gap between the filter (7) and the two side plates of the filter support (8).

3. A filter assembly as claimed in claim 1, wherein, The top of the U-shaped groove of the filter holder (8) is higher than the filter (7).

4. A narrow band filter, characterized by, include: The tube housing (1), the semiconductor cooler (2), the welding base plate (3), the collimator assembly, the tube housing cover plate (6), and the filter assembly according to any one of claims 1-3 are provided with optical fiber tubes (11) on both sides of the tube housing (1), the tube housing cover plate (6) covers the tube housing (1), the collimator assembly and the filter support (8) are welded to the upper surface of the welding base plate (3), the welding base plate (3) is welded to the semiconductor cooler (2), and the semiconductor cooler (2) is welded to the base plate (12) inside the tube housing (1).

5. A narrow band filter as claimed in claim 4, characterised in that, Also includes: Temperature sensor (9) is welded to the welding base plate (3) near the filter assembly.

6. A narrow band filter as claimed in claim 4, wherein, At least one injection hole (111) is provided above the optical fiber tube (11) for injecting solder to fill the optical fiber tube (11).

7. A narrow band filter as claimed in claim 4, wherein, The tube shell (1) also includes a base plate (12), a ring frame (13), a lead pin (14) and an insulator (15), wherein the optical fiber tube (11) is respectively arranged on opposite sides of the ring frame (13), the base plate (12) is fixed to the bottom of the ring frame (13), the lead pin (14) extends out of the front panel of the ring frame (13), and an insulator (15) is arranged between the lead pin (14) and the ring frame (13).

8. A narrow band filter as claimed in claim 4, wherein, The collimator assembly includes a collimator bracket (4) and an optical fiber collimator (5). The optical fiber collimator (5) is welded to the collimator bracket (4), and the bottom of the collimator bracket (4) is welded to the upper surface of the welding base plate (3).

9. A narrow band filter as claimed in claim 8, characterised in that, The gold-plated tube (51) of the fiber optic collimator (5) is fitted into the collimator bracket (4).

10. A narrow band filter as claimed in claim 9, wherein, The collimator bracket (4) is saddle-shaped, including a central arc-shaped kit and side wall welding planes and bottom welding planes formed by extending downwards and folding from both sides of the arc-shaped kit. The collimator bracket (4) is welded and fixed to the front and rear sides of the gold-plated tube (51) of the fiber optic collimator (5) through the side wall welding planes.

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