Tunable optical filter assembly and BOSA structure

Abstract

A tunable optical filter assembly disclosed by the present invention comprises a tunable optical filter, a substrate, a flexible circuit board, a temperature sensor, a cooling fin and a thermoelectric refrigerating unit, the flexible circuit board is arranged on the substrate, and the tunable optical filter, the temperature sensor and the thermoelectric refrigerating unit are all arranged on a metal layer of the flexible circuit board. The thermoelectric refrigerating unit is tightly attached to the tunable optical filter, the hot face of the thermoelectric refrigerating unit is attached to the metal layer of the flexible circuit board, and the cold face of the thermoelectric refrigerating unit is attached to the cooling fin. The cooling fins are arranged on the thermoelectric refrigerating unit, and the cooling fins located on the two sides of the thermoelectric refrigerating unit make contact with the board face of the flexible circuit board and keep away from the metal layer of the flexible circuit board. The invention has the advantages that: the special-shaped radiating fins are arranged on the soft belt provided with the substrate by reversely utilizing the TEC; the total thickness is only 1.75 mm, because the cooling fins are provided with large chamfers, the lens can go deep into the center of the tunable optical filter assembly, and the actual thickness value is increased by 1.2-1.5 mm.

Description

Technical Field

[0001] The present invention relates to the technical field of optical transmitting and receiving subassembly (hereinafter referred to as BOSA), and in particular to a tunable optical filter assembly. Background Art

[0002] With the development of optical communication technology, the requirements for PON optical modules are getting higher and higher. In order to increase the transmission distance, users are expected to use wavelength division multiplexers instead of splitters to reduce insertion loss; thus, tunable optical filters are required at the receiving end to filter out unnecessary wavelengths.

[0003] However, the complex structure is too thick, making BOSA design very difficult, and even the low-cost traditional BOSA structure cannot be used. Therefore, how to reduce the thickness of the tunable optical filter assembly has become an urgent problem to be solved. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to reduce the thickness of a tunable optical filter assembly.

[0005] In order to solve the above technical problems, the present invention proposes a tunable optical filter assembly, which adopts a special-shaped heat sink and is reversely mounted on a flexible circuit board equipped with a substrate using a thermoelectric cooler TEC. The total thickness is only 1.75 mm. Since the heat sink has a large chamfer, the lens of the light receiving component in the optical module can penetrate into the center of the tunable optical filter assembly, and the actual thickness value increases by 1.2~1.5 mm. Therefore, the traditional BOSA structure can be conveniently adopted, which greatly reduces the cost.

[0006] The specific technical solutions adopted are as follows: A tunable optical filter assembly comprises a tunable optical filter, a substrate, a flexible circuit board, a temperature sensor, a heat sink and a thermoelectric cooler. The flexible circuit board is arranged on the substrate. The tunable optical filter, the temperature sensor and the thermoelectric cooler are all arranged on the metal layer of the flexible circuit board. The thermoelectric cooler is closely attached to the tunable optical filter, and the hot surface of the thermoelectric cooler is attached to the metal layer of the flexible circuit board, and the cold surface of the thermoelectric cooler is attached to the heat sink. The heat sink is arranged on the thermoelectric cooler, and the heat sinks located on both sides of the thermoelectric cooler are in contact with the board surface of the flexible circuit board and avoid the metal layer of the flexible circuit board. The heat sink does not block the tunable optical filter and the temperature sensor.

[0007] In a further preferred embodiment of the technical solution of the present invention, the heat sink comprises an L-shaped heat sink body, and three arc surfaces are arranged on the outer surface of the L-shaped heat sink body, and the three arc surfaces are respectively located at the outermost ends of the L-shaped heat sink body and at the right-angle turning point. The three arc surfaces are designed to allow the tunable optical filter assembly of the present invention to be installed in the mounting hole of the BOSA body.

[0008] In a further preferred embodiment of the technical solution of the present invention, a glue isolation groove is provided on two adjacent arc surfaces along the height direction of the L-shaped heat sink body, and a thermal conductive glue is coated on the outer surface of the L-shaped heat sink body between the two glue isolation grooves. The glue isolation groove prevents the thermal conductive glue from overflowing onto the thermoelectric cooler, resulting in a short hot and cold surface.

[0009] In a further preferred embodiment of the technical solution of the present invention, the upper end surface of the heat sink is concavely arranged to avoid the chamfer of the lens in the light receiving assembly. The chamfer is to avoid the lens of the light receiving assembly, so that the light receiving assembly can use the space in the tunable optical filter, so that the tunable optical filter assembly of the present invention can be applied to the traditional BOSA structure.

[0010] In a further preferred embodiment of the technical solution of the present invention, the lower end surface of the heat sink is cut inwardly to form a gap for installing the thermoelectric cooler, and grooves are cut on the lower end surfaces of the heat sink on both sides of the gap to avoid the metal layer on the flexible circuit board.

[0011] In a further preferred embodiment of the technical solution of the present invention, a first foot and a second foot are provided on the lower end surface of the heat sink; in order to better fix the heat sink, the first foot and the second foot are both glued to the flexible circuit board and avoid the metal layer of the flexible circuit board.

[0012] In a further preferred embodiment of the technical solution of the present invention, the temperature sensor is close to the tunable optical filter and soldered on the metal layer of the flexible circuit board. The temperature sensor is close to the tunable optical filter in order to accurately reflect the temperature of the tunable optical filter.

[0013] In a further preferred embodiment of the technical solution of the present invention, metal layers are symmetrically arranged on the flexible circuit board, and a bottleneck area is provided between the metal layers.

[0014] In a further preferred embodiment of the technical solution of the present invention, the base plate is made of FRP glass fiber reinforced resin plate.

[0015] The present invention also proposes a BOSA structure, comprising a BOSA body, a light receiving component, a light transmitting component and the tunable optical filter component described in any one of claims 1 to 9, wherein the light transmitting component is installed in the BOSA body and coupled, the tunable optical filter component is installed in the BOSA body, and the light receiving component is installed in the BOSA body and coupled.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The tunable optical filter assembly of the present invention adopts a special-shaped heat sink, which is reversely mounted on a soft belt with a substrate using TEC. The total thickness is only 1.75 mm. Since the heat sink has a large chamfer, the lens can penetrate into the center of the tunable optical filter assembly, and the actual thickness value increases by 1.2-1.5 mm.

[0017] The BOSA structure using the tunable optical filter assembly of the present invention can conveniently use the traditional BOSA structure, thereby greatly reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of a first direction of a tunable optical filter assembly in Example 1; Figure 2 is a schematic diagram of the structure of the tunable optical filter assembly in the second direction of Example 1; Figure 3 is a front view of the tunable optical filter assembly of Example 1; Figure 4 yes Figure 3 AA cut view; Figure 5 yes Figure 3 A front view of the tunable optical filter assembly of this embodiment with the heat sink hidden; Figure 6 yes Figure 5 BB cutaway view; Figure 7 is a three-dimensional schematic diagram of the heat sink in a first direction; Figure 8 is a three-dimensional schematic diagram of the heat sink in a second direction; Fig. 9 It is a three-dimensional schematic diagram of the heat sink in the third direction; Fig.10 It is a front view of the BOSA structure of this embodiment; Fig.11 yes Fig.10 CC cutaway view; Fig.12 is a front view of a tunable optical filter assembly of Example 2 of Example 2; Among them, 1-flexible circuit board, 2-heating resistor, 3-tunable optical filter, 4-temperature sensor, 5-substrate, 51-light hole, 6-heat sink, 61-chamfer, 62-glue isolation groove, 63-first foot, 64-second foot, 65-arc surface, 66-notch, 67-groove, 7-thermoelectric cooler, 8-tunable optical filter assembly, 9-45 degree filter, 10-light receiving assembly, 10-1, lens, 11-light emitting assembly, 12-BOSA body. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the following Figure 1-Figure 12The present invention is further described in detail with reference to the embodiments. 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. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other. Example 1

[0020] like Figure 1-6 As shown, this embodiment is a tunable optical filter assembly, including a flexible circuit board 1, a tunable optical filter 3, a temperature sensor 4, a substrate 5, a heat sink 6 and a thermoelectric cooler 7.

[0021] like Figure 7-9 The tunable optical filter assembly of this embodiment uses a shaped heat sink, which is reversely mounted on a flexible circuit board 1 equipped with a substrate 5 by using a thermoelectric cooler 7 (TEC).

[0022] The total thickness of the tunable optical filter assembly is only 1.75 mm. Since the heat sink 6 has a large chamfer, the lens can penetrate into the center of the tunable optical filter assembly, and the actual thickness value increases by 1.2-1.5 mm. Therefore, the traditional BOSA structure can be easily adopted, which greatly reduces the cost.

[0023] like Figure 5-6 As shown, the relative positions of the flexible circuit board 1, the tunable optical filter 3, the temperature sensor 4, the substrate 5 and the thermoelectric cooler 7 are known. The flexible circuit board 1 and the substrate 5 are glued and fixed. The substrate 5 is a heat-insulating material, preferably made of FRP glass fiber reinforced resin board. In actual production, the flexible circuit board 1 is processed in one piece by the manufacturer, and a light hole 51 is provided in the middle.

[0024] like Figure 5 As shown, a bottleneck area 1-1 is provided on the flexible circuit board 1, which is to reduce the heat transferred to the outside and improve the heating and cooling efficiency.

[0025] like Figure 5-6 As shown, the tunable optical filter 3, the temperature sensor 4 and the thermoelectric cooler 7 are all arranged on the metal layer 1-2 of the flexible circuit board 1; the temperature sensor 4 is close to the tunable optical filter 3, in order to accurately reflect the temperature of the tunable optical filter 3. Since the thermoelectric cooler 7 is relatively high, it can only be placed on the side of the tunable optical filter 3, so that the hot surface of the thermoelectric cooler 7 can only transfer heat to the tunable optical filter 3 through the metal layer on the flexible circuit board 1. At the same time, the cold surface of the thermoelectric cooler 7 is attached to the heat sink 6, which is exactly the opposite of the traditional thermoelectric cooler structure. This is because when installed in this way, the electrodes of the thermoelectric cooler face upward, which is convenient for wiring.

[0026] like Figure 7-9As shown, the heat sink 6 is of a special shape and is made of aluminum alloy. It includes an L-shaped heat sink body. The heat sink 6 is L-shaped as a whole. The L-shaped heat sink body has a large chamfer on the inside. Specifically, the upper end surface of the L-shaped heat sink body is concave and is used to avoid the chamfer 61 of the lens in the light receiving component 10. The chamfer 61 is to avoid the lens of the light receiving component, so that the light receiving component can use the space in the tunable optical filter, which actually reduces the occupied space.

[0027] like Figure 3 and 9 As shown, the side of the L-shaped heat sink body is bonded to the inner cavity of the BOSA with thermal conductive adhesive, specifically: three arc surfaces 65 are set on the outer surface of the L-shaped heat sink body, and the three arc surfaces 65 are respectively at the outermost ends of the L-shaped heat sink body and the right-angle turning point; a glue isolation groove 62 is set on each of the two adjacent arc surfaces 65 along the height direction of the L-shaped heat sink body, and the thermal conductive adhesive is coated on the outer surface of the L-shaped heat sink body between the two glue isolation grooves 62. The two glue isolation grooves 62 prevent the thermal conductive adhesive from overflowing onto the thermoelectric cooler 7, causing a short circuit between the hot and cold surfaces of the thermoelectric cooler 7.

[0028] like Figure 7 and 8 As shown, the lower end surface of the L-shaped heat sink body is cut inwardly to form a notch 66 for installing the thermoelectric cooler 7, and grooves 67 are cut on the lower end surface of the heat sink 6 on both sides of the notch 66 to avoid the metal layer on the flexible circuit board 1. Figure 7-9 As shown, the remaining portion on the lower end surface of the heat sink 6 is provided with a first pin 63 and a second pin 64; the first pin 63 and the second pin 64 are both glued to the flexible circuit board 1 and avoid the metal layer of the flexible circuit board 1; the first pin 63 and the second pin 64 are both very narrow.

[0029] like Figure 10-11 As shown, this embodiment proposes a BOSA structure.

[0030] Since the size of the SFP optical module is fixed, the traditional BOSA structure has only more than 1 mm of space left, and the usual structure cannot fit in. The traditional BOSA structure is very mature, the cost of components is low, the tooling fixtures are ready-made, and the OEM cost is low.

[0031] Therefore, the design proposed in the present invention can use the traditional 45-degree filter BOSA structure, which greatly reduces the cost and has good economic benefits.

[0032] The tunable optical filter assembly 8 of this embodiment has a total thickness of only 1.75 mm. Since the heat sink 6 has a large chamfer 61, the chamfer 61 is to avoid the lens 10-1 of the light receiving assembly 10, so that the light receiving assembly can use the space in the tunable optical filter, which actually reduces the occupied space. The lens 10-1 can go deep into the center of the tunable optical filter assembly, and the actual thickness value increases by 1.2-1.5 mm. Therefore, the traditional BOSA structure can be conveniently adopted, which greatly reduces the cost.

[0033] The BOSA structure of this embodiment includes a BOSA body 12, a light receiving component 10, a light transmitting component 11 and a tunable optical filter component 8. The light transmitting component 11 is installed in the BOSA body 12 and coupled, the tunable optical filter component 8 is installed in the BOSA body 12, and the light receiving component 10 is installed in the BOSA body 12 and coupled and fixed.

[0034] As shown in the figure, the light entering the BOSA structure from the outside on the right side is reflected by the 45-degree filter 9, and then passes through the tunable optical filter assembly 8 and enters the optical receiving assembly 10. The narrowband reception of the optical signal is realized. The optical signal emitted by the optical transmitting assembly 11 passes through the 45-degree filter 9 and is transmitted to the external optical fiber, realizing the emission of the optical signal. Example 2

[0035] like Fig.12 As shown, this embodiment also provides a tunable optical filter assembly, including a flexible circuit board 1, an electric heating resistor 2, a tunable optical filter 3, a temperature sensor 4 and a substrate 5.

[0036] The difference between this embodiment and embodiment 1 is that a heating resistor 2 with a small adjustment range is used to replace the thermoelectric cooler 7. Without the thermoelectric cooler 7, the internal temperature is not high and the heat sink 6 is not needed. The rest of the structure is the same as that of embodiment 1.

[0037] The heating resistor 2 of this embodiment is glued on the tunable optical filter 3. In order to improve the heating efficiency, the temperature of the tunable optical filter 3 is changed by heating to change the central wavelength of the wave.

[0038] The advantage of the tunable optical filter assembly of this embodiment over that of the embodiment 1 is that it is cheap. As is known to those skilled in the art, the price of the thermoelectric cooler 7 is high, while the price of the heating resistor 2 is cheap. The disadvantage is that the adjustment range is small and it can only heat. The thermoelectric cooler 7 has a large adjustment range and can both heat and cool.

[0039] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A tunable optical filter assembly, comprising a tunable optical filter (3) and a substrate (5), characterized in that: It also comprises a flexible circuit board (1), a temperature sensor (4), a heat sink (6) and a thermoelectric cooler (7), wherein the flexible circuit board (1) is arranged on a substrate (5), the tunable optical filter (3), the temperature sensor (4) and the thermoelectric cooler (7) are all arranged on a metal layer of the flexible circuit board (1), the thermoelectric cooler (7) is closely attached to the tunable optical filter (3), the hot surface of the thermoelectric cooler (7) is attached to the metal layer of the flexible circuit board (1), and the cold surface of the thermoelectric cooler (7) is attached to the heat sink (6); The heat sink (6) is arranged on the thermoelectric cooler (7), and the heat sinks (6) located on both sides of the thermoelectric cooler (7) contact the board surface of the flexible circuit board (1) and avoid the metal layer of the flexible circuit board (1); the heat sink (6) does not block the tunable optical filter (3) and the temperature sensor (4).

2. The tunable optical filter assembly according to claim 1, characterized in that: The heat sink (6) comprises an L-shaped heat sink body, and three arc surfaces (65) are arranged on the outer surface of the L-shaped heat sink body, wherein the three arc surfaces (65) are respectively located at the outermost ends of the L-shaped heat sink body and at a right-angle turning point.

3. The tunable optical filter assembly according to claim 2, characterized in that: A glue isolation groove (62) is provided on two adjacent arc surfaces (65) along the height direction of the L-shaped heat sink body, and a heat conductive glue is coated on the outer surface of the L-shaped heat sink body between the two glue isolation grooves (62).

4. The tunable optical filter assembly according to claim 2, characterized in that: The upper end surface of the heat sink (6) is concavely arranged to avoid the chamfer (61) of the lens in the assembled light receiving component.

5. The tunable optical filter assembly according to claim 2, characterized in that: The lower end surface of the heat sink (6) is cut inwardly to form a notch (66) for installing the thermoelectric cooler (7), and grooves (67) are cut on the lower end surface of the heat sink (6) on both sides of the notch (66) to avoid the metal layer on the flexible circuit board (1).

6. The tunable optical filter assembly according to claim 5, characterized in that: The lower end surface of the heat sink (6) is provided with a first foot (63) and a second foot (64); the first foot (63) and the second foot (64) are both glued to the flexible circuit board (1) and avoid the metal layer of the flexible circuit board (1).

7. The tunable optical filter assembly according to claim 1, characterized in that: The temperature sensor (4) is close to the tunable optical filter (3) and is soldered on the metal layer of the flexible circuit board (1).

8. The tunable optical filter assembly according to claim 1, characterized in that: Metal layers are symmetrically arranged on the flexible circuit board (1), and a bottleneck area (11) is provided between the metal layers.

9. The tunable optical filter assembly according to claim 1, characterized in that: The base plate (5) is made of FRP glass fiber reinforced resin plate.

10. A BOSA structure, characterized in that: The optical transmission device comprises a BOSA body (12), a light receiving assembly (10), a light transmitting assembly (11), and a tunable optical filter assembly (8) according to any one of claims 1 to 9, wherein the light transmitting assembly (11) is installed in the BOSA body (12) and coupled, the tunable optical filter assembly (8) is installed in the BOSA body (12), and the light receiving assembly (10) is installed in the BOSA body (12) and coupled and fixed.

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