Optical fiber-chip packaging method based on carbon dioxide laser

Abstract

The invention discloses an optical fiber-chip packaging method based on carbon dioxide laser processing, and the method comprises the following steps: arranging a thinning region at the end surface, needing to be connected, of a substrate layer of an optical fiber and a chip, carrying out the butt joint of the thinning region of the substrate layer of the optical fiber and the chip, placing a butt joint seam of the thinning region below a laser action region, and carrying out the welding. According to the invention, rapid, stable and high-strength connection between the substrate layers is realized by matching carbon dioxide laser with the thinning area, a high-precision alignment state is ensured, a butt joint surface does not need to be polished, and a feasible scheme is provided for welding and packaging between optical fibers with different sizes and different materials and chips.

Description

TECHNICAL FIELD

[0001] The present application relates to a packaging method, in particular to an optical fiber-chip packaging method. BACKGROUND

[0002] The coupling packaging of optical fibers and chips is an important part of optical electronic devices such as modulators, optical chips and lasers, and is one of the core requirements of the next generation of optical interconnection networks. A good packaging method can stably maintain the coupling efficiency within the required range, effectively widening the application scenarios of optical chip devices.

[0003] Traditional packaging methods include glue packaging, mechanical structure packaging and welding packaging. Glue packaging uses epoxy resin, ultraviolet glue, etc. to fix the optical fiber at the required position after alignment, but using glue has the disadvantages of stress deviation during solidification, aging and high-temperature failure, strong temperature and humidity sensitivity, and mismatched thermal expansion coefficients, which leads to a significant decrease in coupling efficiency in high-temperature environments, limiting the application scenarios of optical fiber devices. Mechanical structure packaging usually uses mechanical structures to hold the optical fiber and then fix it to the specified position for coupling and packaging with the chip. The additional stress introduced by the mechanical holding structure increases the optical fiber loss and increases the fixing volume, which is also not suitable for high-temperature application scenarios. Welding packaging is often combined with laser processing, and common laser processing methods include femtosecond laser processing and carbon dioxide laser processing. The contact distance between the welding material and the optical fiber during femtosecond laser processing is usually required to be within the optical distance (λ / 4), and the mechanical device is relatively complex and costly. When facing optical chip packaging with different sizes and materials of optical fibers, femtosecond laser processing has the problems of high alignment difficulty, requirement for smooth contact end, complex processing process and possible introduction of end face damage, which limits the application of femtosecond laser technology. SUMMARY

[0004] The purpose of the present application is to provide a polishing-free butt joint base layer packaging method.

[0005] Technical solution: The optical fiber-chip packaging method based on carbon dioxide laser processing provided by the present application comprises the following steps: setting a thinning area at the end face of the base layer of the optical fiber and the chip where connection is required, butting the optical fiber and the chip and placing the butt joint seam of the base layer under the laser action area, and performing fusion.

[0006] Preferably, the thickness of the base layer is 0.5-4 mm, and the thickness of the thinning area is 0.1-0.5 mm.

[0007] Preferably, the size L1 of a single thinning area in the width direction of the base layer does not exceed half of the width L3 of the base layer, and the size L2 in the length direction of the base layer does not exceed half of the length L4 of the base layer.

[0008] Preferably, the thinning area is symmetrically distributed along the midline of the base layer in the length direction.

[0009] Preferably, the thinning area is two, starting from the sidewall in the length direction of the base layer and extending to the midline.

[0010] Preferably, the diameter of the laser action area is 200-1000 μm, and the center of the laser action area overlaps the butt joint of the thinning area.

[0011] Preferably, the chip is selected from at least one of lithium niobate-based chip, high borosilicate chip, silicon-based chip, glass-based chip, sapphire-based chip, or wide bandgap semiconductor chip.

[0012] Preferably, the optical fiber is connected to the base layer through the adapter layer, and the connection method of the optical fiber, the adapter layer, and the base layer is:

[0013] (1) Place the adapter layer above the optical fiber, place the contact area of the optical fiber and the adapter layer under the laser action area, and fuse the adapter layer and the optical fiber;

[0014] (2) After turning over the sample in step (1) (because the optical fiber is below the adapter layer in the first step, the optical fiber is on the top in the following steps), stack it on the base layer, make the surface of the adapter layer away from the optical fiber contact the base layer, place the stacking joint of the adapter layer and the base layer under the laser action area, and fuse the adapter layer and the base layer.

[0015] Preferably, in step (1), the center of the laser action area overlaps the axis of the optical fiber.

[0016] Preferably, in step (2), the center of the laser action area overlaps the stacking joint.

[0017] Preferably, the material of the adapter layer and the base layer is high borosilicate, silicon, or silicon oxide.

[0018] Preferably, the thickness of the adapter layer is 100-300 μm.

[0019] Beneficial effects: Compared with the prior art, the present application has the following advantages: 1. Carbon dioxide laser cooperates with the thinning area to realize fast, stable, and high-strength connection of the base layer-base layer, ensures high-precision alignment state, and the butt joint surface does not need to be polished; 2. The present application uses flip-chip bonding method, carbon dioxide laser directly acts on the adapter layer, avoids damage to the optical fiber structure, maintains the advantage of low transmission loss of the optical fiber, and realizes high-strength fixation of the optical fiber and the adapter layer; 3. The packaging method used in the present application completes the fusion packaging of the optical fiber-adapter layer, adapter layer-base layer, and base layer-base layer on a set of devices, can realize high-strength and damage-free welding and packaging of the optical fiber and the chip, meets the use requirements in complex environments such as high temperature and high humidity, and provides a feasible scheme for welding and packaging of optical fibers and chips of different sizes and different materials. Attached Figure Description

[0020] Figure 1 This is an isometric view of the optical fiber and adapter layer welding principle described in an embodiment of the present invention;

[0021] Figure 2 This is a front view of the optical fiber and adapter layer welding principle described in an embodiment of the present invention;

[0022] Figure 3 This is a front view of the welding principle of the transition layer and base layer described in an embodiment of the present invention;

[0023] Figure 4 This is an axonometric view of the substrate layer and the substrate layer welding principle described in an embodiment of the present invention;

[0024] Figure 5 This is an axial front view of the base layer and the base layer welding principle described in the embodiments of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0026] Example: In this embodiment, fiber 1 is a standard single-mode fiber, and the adapter layer 2 and substrate layer 3 are made of high borosilicate material. The thickness of adapter layer 2 is 190 μm, and the thickness of substrate layer 3 is 3 mm. The overall fabrication process consists of three parts: encapsulation of fiber 1 and adapter layer 2, encapsulation of adapter layer 2 and substrate layer 1, and encapsulation of substrate layers with each other. Detailed fabrication steps are described below:

[0027] (1) such as Figure 1 , Figure 2 As shown, fiber 1 is cut to a suitable length, the cladding is removed, and it is placed in the V-groove of fixture 5. Adapter layer 2 is placed above fiber 1. Using the weight of adapter layer 2, it contacts fiber 1. The end plate of fixture 5 or other dimensional measuring fixture is used to align the adapter layer 2 and the end face of fiber 1. A Gaussian beam of carbon dioxide laser is used, and a focused spot is formed through focusing lens 7, acting on the upper surface of adapter layer 2. The diameter of the spot's effective area is approximately 200 μm. The center of the spot is adjusted to overlap with the axis of fiber 1. Fixture 5 is moved so that the spot scans along the length / axis of fiber 1. The contact position 6a between fiber 1 and adapter layer 2 is welded, completing the fusion and forming the encapsulated semi-finished product I. Fixture 5 is made of metal, such as stainless steel.

[0028] (3) such as Figure 3, remove the tool 5, flip the semi-finished product I upside down and place it on the base layer 3, align the end faces of the optical fiber 1, the adapter layer 2 and the base layer 3 and move the sample so that the center of the laser spot is located on the boundary line between the adapter layer 2 and the base layer 3 / the boundary line between the stacking seams 6b, that is, the adapter layer 2 and the base layer 3 each occupy one half of the action area of the spot, move along the length direction of the optical fiber 1, fuse the adapter layer 2 and the base layer 3 at the boundary lines 6b, 6c, and form the packaged semi-finished product II.

[0029] (4) as Figure 4 , Figure 5 , after thinning the end face of the packaged semi-finished product II, the abutting end face of the base layer 3a, 3b of the chip 4, align the optical fiber and the chip and apply a certain pressure, move the sample, place the abutting seam of the base layer of the optical fiber and the chip under the laser action area, and each of the two base layers 3a, 3b occupies one half of the spot area. Start the carbon dioxide laser, weld the abutting seams 6d, 6e of the thinned areas of the base layers 3a, 3b, and complete the optical fiber-chip fusion packaging.

[0030] The optical fiber-chip packaging is completed according to the above process, the optical fiber 1 can be replaced by a variety of materials, multi-mode, polarization maintaining or other types of special optical fibers and optical fiber arrays, the adapter layer 2 and the base layer 3 can be replaced by silicon or silicon oxide and the like, the thickness of the adapter layer 2 can be adjusted in the range of 100-300 μm, the thickness of the base layer 3 can be adjusted in the range of 0.5-4 mm, and the diameter of the laser action area (spot) can be continuously adjusted in the range of 200-1000 μm.

[0031] The pre-set thinning area at the end face of the base layer 3 is preferably symmetrically distributed along the center line of the length direction of the base layer. Starting from the sidewall in the length direction of the base layer, the thinning area extends to the center line. The thickness H of the thinning area can be adjusted in the range of 0.1-0.5 mm, the size L1 of a single thinning area in the width direction of the base layer 3 is not more than half of the width L3 of the base layer 3, the size L2 in the length direction of the base layer 3 is not more than half of the length L4 of the base layer 3, and the specific size is selected according to the use requirement. The thinning process can be grinding or laser thinning, and the thinning area can be formed before the base layer 3 is connected with the adapter layer 2.

[0032] The processing method used in the application is carbon dioxide laser processing, which has the advantages of precise controllable action area and no introduction of impurities in the packaging process, and can meet the packaging requirements of various materials, single-mode, multi-mode, polarization maintaining or other types of special optical fibers. The chip processed by the packaging method of the application is firmly fused, does not need to introduce other materials, has strong durability, can meet the use requirements in complex and extreme environments, and has wide application prospect.

Claims

1. A fiber-to-chip packaging method based on carbon dioxide laser, characterized in that, Includes the following steps: A thinning zone is set at the end face where the substrate layer of the optical fiber and the chip needs to be connected. The optical fiber and the chip are then connected, and the joint of the thinning zone is placed below the laser action area for fusion splicing.

2. The fiber-to-chip packaging method according to claim 1, characterized in that, The thickness of the base layer is 0.5-4 mm, and the thickness of the thinned zone is 0.1-0.5 mm.

3. The fiber-to-chip packaging method according to claim 1, characterized in that, The dimension L1 of a single thinned region along the width direction of the substrate layer does not exceed half of the substrate layer width L3, and the dimension L2 along the length direction of the substrate layer does not exceed half of the substrate layer length L4.

4. The fiber-to-chip packaging method according to claim 1, characterized in that, The thinning zone is symmetrically distributed along the midline of the base layer length direction.

5. The fiber-to-chip packaging method according to claim 1 or 4, characterized in that, The thinning zone consists of two regions, starting from the sidewall along the length of the basal layer and extending towards the midline.

6. The fiber-to-chip packaging method according to claim 1, characterized in that, The diameter of the laser-affected area is 200-1000 μm, and the center of the laser-affected area overlaps with the seam of the thinning area.

7. The fiber-to-chip packaging method according to claim 1, characterized in that, The optical fiber is connected to the substrate layer via an adapter layer. The connection method between the optical fiber, adapter layer, and substrate layer is as follows: (1) The optical fiber is placed below the transition layer, and the contact area of ​​the optical fiber and the transition layer is placed below the laser action area. The optical fiber and the transition layer are then fused together. (2) Stack the sample obtained in step (1) on the base layer, so that the surface of the transition layer away from the optical fiber contacts the base layer, place the stacking seam of the transition layer and the base layer below the laser action area, and fuse the transition layer and the base layer.

8. The fiber-to-chip packaging method according to claim 7, characterized in that, In step (1), the center of the laser action area overlaps with the fiber axis.

9. The fiber-to-chip packaging method according to claim 7, characterized in that, In step (2), the center of the laser action area overlaps with the stacking seam.

10. The fiber-to-chip packaging method according to claim 7, characterized in that, The transition layer and the base layer are made of high borosilicate, silicon or silicon oxide, and the thickness of the transition layer is 100-300 μm.

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