Optical waveguide modulator chip coupling packaging structure and packaging process method thereof

Abstract

The invention discloses an optical waveguide modulator chip coupling packaging structure and a packaging process method thereof, and belongs to the field of optical waveguide packaging. The packaging structure comprises a packaging carrier, an optical waveguide modulator chip, an input optical fiber assembly and an output optical fiber assembly, the packaging carrier is divided into a first area used for placing the optical waveguide modulator chip and a second area used for fixing the input optical fiber assembly and the output optical fiber assembly, and a groove structure is arranged between the first area and the second area. The two optical fibers are adopted for independent coupling, so that each optical fiber can be ensured to be located at the optimal coupling position, and the factor that the coupling loss is increased due to array optical fiber manufacturing errors is eliminated; the optical fiber fixing hole and the chip bonding surface are manufactured on the same carrier, so that the situation that the optical coupling loss is increased due to structural deformation and incoordination caused by temperature change due to the difference of material expansion coefficients can be avoided; and the optical fiber is fixed by filling glue or welding flux on the carrier through the fixing hole, so that the reliability is high under the condition of load or temperature change.

Description

Technical Field

[0001] The present invention belongs to the field of optical waveguide packaging, and particularly relates to an optical waveguide modulator chip coupling and packaging structure and a packaging process method thereof. Background Art

[0002] An optical waveguide modulator is a key device in optical fiber communication, mainly used for modulating the intensity, phase, polarization, etc. of an optical signal while keeping the original frequency of the optical signal unchanged to meet different transmission requirements. The difficulty in fabricating an optical waveguide modulator lies in the coupling and packaging process between the modulator chip and the optical fiber, which requires accurately transmitting the transmitted optical signal in the optical fiber into the chip, and after being modulated by the chip, transmitting the optical signal to the output optical fiber. Both sides or one side edge of the optical waveguide modulator has an optical coupling region, usually with two ports of optical input and optical output, and optical coupling is achieved by aligning the optical fiber with the chip coupling region. In the prior art, an array optical fiber component (making the input and output optical fibers on an array) is usually used to

[0003] couple and align with the chip end face for fixation. This coupling method is difficult to achieve the most ideal coupling effect because there are usually certain precision errors in the fabrication of the optical fiber array component, which will make it difficult to reach the best coupling positions with the two coupling ports of the chip simultaneously. In addition, this commonly used end face coupling method mainly realizes adhesive fixation through the optical fiber component and the chip end face, and the bottom is in a suspended state without being fixed to the chip carrier or housing, and is relatively vulnerable to external forces such as vibration and collision, which may affect the alignment deviation and further affect the stability of optical transmission. Summary of the Invention

[0004] Object of the Invention: The first object of the present invention is to provide an optical waveguide modulator chip coupling and packaging structure capable of realizing optical coupling of the optical waveguide modulator chip and improving its coupling accuracy and reliability. The second object of the present invention is to provide a packaging process method for the above-mentioned optical waveguide modulator chip coupling and packaging structure.

[0005] Technical Solution: The optical waveguide modulator chip coupling and packaging structure described in the present invention includes: a packaging carrier, an optical waveguide modulator chip, an input optical fiber component, and an output optical fiber component. The packaging carrier is divided into a first area for placing the optical waveguide modulator chip and a second area for fixing the input optical fiber component and the output optical fiber component. A groove structure for preventing chip contamination is provided between the first area and the second area.

[0006] Further, the first area includes a chip bonding plane and limit steps provided at both ends of the chip bonding plane to facilitate chip patch positioning.

[0007] Furthermore, the planar height of the groove should be lower than the chip bonding plane. When bonding the chip, the bottom of the optical coupling region of the chip is suspended, preventing the bonding material at the bottom of the chip from overflowing and contaminating the optical coupling region of the chip, thereby affecting the coupling efficiency.

[0008] Furthermore, the encapsulation carrier material is a material with a difference in thermal expansion coefficient from the optical waveguide modulator chip within 2 times.

[0009] Preferably, the materials of the encapsulation carrier include materials such as kovar alloy, aluminum nitride ceramic, silicon carbide ceramic, silicon nitride ceramic, and borosilicate glass. Since optical coupling is sensitive to displacement, mismatched thermal expansion coefficients of different materials may cause relative displacement of optical coupling in the encapsulation structure during temperature changes, thereby increasing the optical coupling loss. Materials with similar thermal expansion coefficients will have similar expansion or contraction during temperature changes, thereby reducing the impact of temperature on coupling loss and improving the optical coupling reliability of the encapsulation.

[0010] Furthermore, the second region includes a fiber optic component fixing component; the fiber optic component fixing component is provided with an input fiber fixing hole and an output fiber fixing hole. Metal tubes are welded to the outer surfaces of the input fiber optic component and the output fiber optic component. The metal tubes pass through the fiber fixing holes of the encapsulation carrier and are coupled and fixed to the optical waveguide modulator chip; among them, the length of the metal tube is greater than the length of the fixing hole, and the length of the metal tube of the input fiber optic component is less than the length of the metal tube of the output fiber optic component, and the difference satisfies at least the clamping of the coupling fixture.

[0011] Furthermore, the central positions of the input fiber optic component fixing hole and the output fiber optic component fixing hole are on the same horizontal extension line as the central position of the optical coupling region on the surface of the optical waveguide modulator chip, that is, the central position height h of the fixing hole = chip thickness h1 + chip bonding layer thickness h2 + carrier chip bonding plane thickness h3, which is convenient for subsequent fiber alignment coupling.

[0012] Furthermore, the input fiber fixing hole and the output fiber fixing hole are provided with filling grooves for accommodating filling materials, facilitating the filling of filling materials such as ultraviolet curable glue or solder after coupling to fix the fiber optic component.

[0013] Furthermore, the diameter d1 of the fiber fixing hole should be greater than the diameter d2 of the metal tube, but the difference should be controlled within 0.2 mm to prevent excessive filling of bonding materials from causing excessive stress or coupling offset.

[0014] Furthermore, the encapsulation carrier and the metal capillary of the fiber optic component adopt a nickel-gold plating process, with a nickel layer of 2 - 5 μm and a gold layer of 0.1 - 1 μm.

[0015] Furthermore, the mode field sizes of the input optical fiber assembly and the output optical fiber assembly match the mode field size of the optical coupling region of the optical waveguide modulator chip, so as to reduce the coupling loss between the chip and the optical fiber.

[0016] The present invention provides a packaging process method for the above-mentioned optical waveguide modulator chip coupling and packaging structure, which includes the following steps:

[0017] (1) Assemble the optical waveguide modulator chip onto the chip bonding plane of the carrier along the limiting step;

[0018] (2) Clamp the metal tube tail of the input optical fiber by a fixture on a high-precision six-axis coupling stage, and align it with the optical input interface of the optical waveguide modulator chip through the input optical fiber fixing hole of the packaging carrier;

[0019] (3) Pass light through the input optical fiber, and then monitor the current of the optical detector at the input end on the optical waveguide modulator chip through a probe, and adjust the position of the input optical fiber to make it reach the maximum value, that is, the maximum input optical power;

[0020] (4) Use a filling material to fill the metal tube on the input optical fiber and bond or weld it to the input optical fiber fixing hole of the packaging carrier;

[0021] (5) Clamp the metal tube of the output optical fiber by a high-precision coupling stage, and align it with the optical output interface of the optical waveguide modulator chip through the output optical fiber fixing hole of the packaging carrier;

[0022] (6) Pass light through the input optical fiber assembly, and adjust the position of the output optical fiber assembly to make the output optical power maximum;

[0023] (7) Use a filling material to bond or weld the metal tube on the output optical fiber assembly to the output optical fiber fixing hole of the packaging carrier.

[0024] Furthermore, in step (1), the glass transition temperature of the bonding material used for assembling the optical waveguide modulator chip onto the packaging carrier should be higher than the curing temperature of the ultraviolet curing glue of the filling material or the melting temperature of the low-temperature solder in steps (4) and (7), so as to avoid the position of the chip from shifting during the subsequent coupling and fixing process, thereby affecting the coupling loss.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects: (1) Compared with the prior art waveguide modulator using the array fiber coupling process method, the present invention uses two fibers for separate coupling, which can ensure that each fiber is in the best coupling position, eliminating the factor of increased coupling loss caused by the manufacturing error of the array fiber; (2) The present invention fabricates the fiber fixing holes and the chip bonding surface on a single carrier, which can avoid the structural deformation incoordination caused by the difference in the coefficient of thermal expansion of materials during temperature change, further leading to an increase in optical coupling loss; (3) The present invention fixes the fiber to the carrier through the fixing holes by filling glue or solder. Compared with the traditional end-face coupling method, it has higher reliability under load or temperature change; (4) The optical waveguide modulator chip coupling and packaging process method of the present invention realizes the optical coupling of the optical waveguide modulator chip, with high coupling accuracy and improved reliability of the coupled and packaged products. Description of the Drawings

[0026] Figure 1 It is a top view of the optical waveguide modulator chip coupling and packaging structure in Embodiment 1;

[0027] Figure 2 It is a side view of the optical waveguide modulator chip coupling and packaging structure in Embodiment 1;

[0028] Figure 3 It is a schematic structural diagram of the packaging carrier in the optical waveguide modulator chip coupling and packaging structure in Embodiment 1;

[0029] Figure 4 It is a schematic diagram of the fiber component in the optical waveguide modulator chip coupling and packaging structure in Embodiment 1. Detailed Description of the Embodiments

[0030] The present invention will be further described in detail below in conjunction with the embodiments and the drawings.

[0031] Embodiment 1: Taking a certain optical waveguide modulator chip as an example for coupling and packaging, the size of the optical waveguide modulator chip is 2.2mm * 12.25mm * 0.5mm, and the interval between its optical input and optical output coupling regions is 1.6mm.

[0032] As Figures 1-4 shown, the optical waveguide modulator chip coupling and packaging structure provided in this embodiment includes a packaging carrier 100, an optical waveguide modulator chip 200, an input fiber component 300, and an output fiber component 400.

[0033] The material of the packaging carrier 100 is kovar alloy material, and its coefficient of thermal expansion is 5.3×10 -6 / °C, which is relatively close to the coefficient of thermal expansion of the silicon, the matrix material of the optical waveguide modulator chip.

[0034] The left end of the encapsulation carrier 100 is provided with a chip bonding plane 101, and there are limiting steps 102 on both sides thereof to facilitate the patch positioning of the optical waveguide modulator chip 200.

[0035] The right end of the encapsulation carrier 100 has two fixed hole structures 103 for the optical fiber assembly. The central position of the fixed hole is on the horizontal extension line at the same height as the optical coupling area on the chip surface, that is, the height h of the central position of the optical fiber fixed hole = the chip thickness h1 + the chip bonding layer thickness h2 + the thickness h3 of the carrier chip bonding plane, which is convenient for subsequent optical fiber alignment and coupling. In this example, the chip thickness h1 is 0.5 mm, the chip bonding layer thickness h2 is 0.05 mm, and the thickness h3 of the carrier chip bonding plane is 1 mm. Therefore, the height of the central position of the optical fiber fixed hole is 1.55 mm.

[0036] A section of input metal tube 301 and output metal tube 401 are welded on the optical fiber assemblies of the input optical fiber assembly 300 and the output optical fiber assembly 400, and are coupled and fixed to the chip by passing the metal tubes through the optical fiber fixed holes 103 of the carrier.

[0037] The length of the metal tube welded on the optical fiber assembly should be greater than the length of the optical fiber fixed hole on the carrier, and the length of the input metal tube 301 should be less than the length of the output metal tube 401, and the difference should at least meet the clamping of the coupling fixture. In this example, the length of the carrier fixed hole is 3 mm, the length of the input metal tube 301 is 5 mm, and the length of the output metal tube 401 is 7 mm, and the difference is 2 mm, which is convenient for fixture clamping.

[0038] The diameter d1 of the optical fiber fixed hole 103 should be greater than the diameter d2 of the metal tube welded on the optical fiber assembly, but the difference should be controlled within 0.2 mm to prevent excessive stress or coupling offset caused by excessive filling of ultraviolet curable glue or solder. In this example, the diameter of the optical fiber fixed hole is 1.1 mm, and the diameter of the metal tube of the optical fiber assembly is 0.9 mm.

[0039] A filling groove 104 for filling ultraviolet curable glue or solder is provided on the optical fiber fixed hole 103 to facilitate the filling of solder or ultraviolet curable glue after coupling to fix the optical fiber assembly.

[0040] A section of groove 105 is provided in the connection part between the chip bonding area and the optical fiber fixed hole of the encapsulation carrier 100. Its plane height should be lower than the chip bonding plane, so that the bottom of the optical coupling area of the chip is suspended when the chip is bonded, preventing the bonding material at the bottom of the chip from overflowing and contaminating the optical coupling area of the chip, thereby affecting the coupling efficiency. In this example, the groove sinks by 0.2 mm.

[0041] The mode field diameters of the optical fibers of the input optical fiber component and the output optical fiber component should match the mode field diameter of the optical coupling region of the chip to reduce the coupling loss between the chip and the optical fiber. In this example, the mode field diameters of the input and output optical fibers and the mode field of the optical coupling region of the chip are all 4 μm.

[0042] The encapsulation carrier 100 and the metal capillary of the optical fiber adopt a nickel-gold plating process, with a nickel layer of 2 - 5 μm and a gold layer of 0.1 - 1 μm.

[0043] The encapsulation process method of the above optical waveguide modulator chip coupling encapsulation carrier structure includes the following steps:

[0044] (1) Assemble the optical waveguide modulator chip onto the chip bonding plane of the carrier along the limiting step;

[0045] (2) Clamp the tail of the metal tube of the input optical fiber through the fixture on the high-precision six-axis coupling platform, and align it with the optical input interface of the optical waveguide modulator chip through the input optical fiber fixing hole of the encapsulation carrier;

[0046] (3) Pass light through the optical fiber, and then monitor the current of the optical detector at the input end on the optical waveguide modulator chip through the probe, and adjust the position of the optical fiber to obtain the maximum value, that is, the maximum input optical power;

[0047] (4) Use a filling material to fill the metal tube on the optical fiber and bond or weld it to fix the input optical fiber fixing hole of the encapsulation carrier;

[0048] (5) Clamp the metal tube of the output optical fiber through the high-precision coupling platform, and align it with the optical output interface of the optical waveguide modulator chip through the output optical fiber fixing hole of the encapsulation carrier;

[0049] (6) Pass light through the input optical fiber component, and adjust the position of the output optical fiber component to obtain the maximum output optical power;

[0050] (7) Use a filling material to bond or weld the metal tube on the output optical fiber component to the output optical fiber fixing hole of the encapsulation carrier.

[0051] Furthermore, in step (1), the glass transition temperature of the bonding material used to assemble the optical waveguide modulator chip onto the encapsulation carrier should be higher than the curing temperature of the ultraviolet curing glue of the filling material or the melting temperature of the low-temperature solder in steps (4) and (7), to avoid the position of the chip from shifting during the subsequent coupling and fixing process, thus affecting the coupling efficiency.

[0052] The optical waveguide modulator chip coupling encapsulation carrier structure prepared in the embodiment of the present invention can achieve that the change amount of the coupling insertion loss is within 0.5 dB during the high and low temperature changes from -40 °C to 80 °C.

Claims

1. An optical waveguide modulator chip coupling and packaging structure, characterized in that Including: A packaging carrier, an optical waveguide modulator chip, an input optical fiber assembly, and an output optical fiber assembly. The packaging carrier is divided into an area one for placing the optical waveguide modulator chip and an area two for fixing the input optical fiber assembly and the output optical fiber assembly. A groove structure for preventing chip contamination is provided between area one and area two.

2. The optical waveguide modulator chip coupling and packaging structure according to claim 1, characterized in that The area one includes a chip bonding plane and limiting steps provided at both ends of the chip bonding plane.

3. The optical waveguide modulator chip coupling and packaging structure according to claim 1, wherein, The material of the packaging carrier is a material with a difference in thermal expansion coefficient within 2 times that of the optical waveguide modulator chip.

4. The optical waveguide modulator chip coupling and packaging structure according to claim 1, characterized in that, The area two includes an optical fiber assembly fixing component.

5. The optical waveguide modulator chip coupling and packaging structure according to claim 4, wherein The optical fiber assembly fixing component is provided with an input optical fiber fixing hole and an output optical fiber fixing hole. Metal tubes are welded to the outer surfaces of the input optical fiber assembly and the output optical fiber assembly.

6. The optical waveguide modulator chip coupling and packaging structure according to claim 5, characterized in that The length of the metal tube is greater than the length of the fixing hole. The length of the metal tube of the input optical fiber assembly is less than the length of the metal tube of the output optical fiber assembly, and the difference satisfies at least the clamping of the coupling fixture.

7. The optical waveguide modulator chip coupling and packaging structure according to claim 5, characterized in that, The central positions of the input optical fiber assembly fixing hole and the output optical fiber assembly fixing hole are on the same horizontal extension line as the central position of the optical coupling area on the surface of the optical waveguide modulator chip.

8. The optical waveguide modulator chip coupling and packaging structure according to claim 5, characterized in that The input optical fiber fixing hole and the output optical fiber fixing hole are provided with filling grooves for accommodating filling materials.

9. The optical waveguide modulator chip coupling and packaging structure according to claim 1, wherein The metal capillary tubes of the packaging carrier and the optical fiber assembly adopt a nickel-gold plating process, with a nickel layer of 2 - 5 μm and a gold layer of 0.1 - 1 μm; the mode field sizes of the input optical fiber assembly and the output optical fiber assembly match the mode field size of the optical coupling area of the optical waveguide modulator chip.

10. A packaging process method for the packaging structure of the optical waveguide modulator chip according to any one of claims 1-9, characterized in that, Including the following steps: (1) Assemble the optical waveguide modulator chip onto the chip bonding plane of the carrier along the limiting steps; (2) Clamp the tail of the metal tube of the input end optical fiber with a fixture on a high-precision six-axis coupling platform, and align it with the optical input interface of the optical waveguide modulator chip through the input optical fiber fixing hole of the packaging carrier; (3) Pass light through the input optical fiber assembly, and then monitor the current of the optical detector at the input end on the optical waveguide modulator chip with a probe, and adjust the position of the input optical fiber to obtain the maximum value, that is, the maximum input optical power; (4) Use a filling material to fill the metal tube on the input optical fiber and bond or weld it to the input optical fiber fixing hole of the packaging carrier for fixation; (5) Clamp the metal tube of the output end optical fiber with a high-precision coupling platform, and align it with the optical output interface of the optical waveguide modulator chip through the output optical fiber fixing hole of the packaging carrier; (6) Pass light through the input optical fiber assembly, and adjust the position of the output optical fiber assembly to obtain the maximum output optical power; (7) Use a filling material to bond or weld the metal tube on the output optical fiber assembly to the output optical fiber fixing hole of the packaging carrier for fixation.

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