End face coupler structure, end face coupler packaging structure and packaging method thereof

Abstract

The invention discloses an end face coupler structure, an end face coupler packaging structure and a packaging method thereof, and relates to the field of integrated photon and coupling packaging, the end face coupler structure comprises an optical fiber array structure, a chip and a gland, and end face couplers of the chip are sequentially arranged along a first direction; the first surface of the substrate is provided with a plurality of positioning grooves which are sequentially arranged along a first direction, and each positioning groove extends to a scribing channel of the chip from one end close to the end face coupler; a to-be-coupled section of each optical fiber body of the optical fiber array structure is arranged in one positioning groove, and the outer side wall of each to-be-coupled section is in contact with two opposite inner side walls of the corresponding positioning groove; the outer wall, close to the first surface, of the gland makes contact with the outer side walls of all the to-be-coupled sections. Two opposite inner side walls of each positioning groove and the outer wall, close to the first surface, of the gland can limit the radial movement of the corresponding optical fiber body; and the to-be-coupled section is butted and coupled with the end face coupler. According to the invention, the packaging efficiency is improved, and the packaging cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated photonics and coupled packaging, and in particular to an end face coupler structure, an end face coupler packaging structure and a packaging method thereof. Background Art

[0002] Silicon-based optoelectronic chips, due to their compatibility with complementary metal oxide semiconductor (CMOS) processes, have shown significant potential for large-scale applications in high-speed optical communications, on-chip sensing, and photonic computing, and have become a research focus in the field of micro-nano optoelectronics. Optical coupling is the key interface connecting the chip's integrated optical circuit and optical fiber. Its efficiency and reliability directly determine the engineering value of silicon photonic chips. Among them, waveguide end-face coupling technology has become the mainstream technical path to achieve efficient chip-to-fiber interconnection due to its advantages such as compact structure, polarization independence, wide spectral response, and strong process compatibility. Cantilever beam end-face coupler is one of the end-face coupling structures, which has advantages such as large mode field and large packaging alignment tolerance. However, the packaging of cantilever beam end-face coupler has problems such as the fragility of the cantilever beam waveguide and difficulty in end-face polishing, which brings great challenges to the optical packaging of cantilever beam end-face coupler.

[0003] When the chip is processed, a scribing path (a deep etched groove) is processed on the leading edge. In this way, the chip is scratched along the groove during the scribing process to avoid hitting the end face coupler. Under normal circumstances, the scribing path must be polished to ensure that the fiber array and the chip end face are seamlessly connected. However, because the cantilever beam coupler is a suspended structure, the end face coupler can easily be damaged during the polishing process. When the existing cantilever beam end face coupler is packaged, the chip end face is usually not polished, and it is directly coupled with the special-shaped fiber array. The coupling contact area is too small, and there is a lack of a positioning structure for the fiber array. The following problems exist: 1. Due to reasons such as adhesive shrinkage or thermal expansion, the core axis of the fiber array and the center of the cantilever beam coupler are easily offset. During the packaging curing process, the coupling loss is easily increased or even the coupling fails. 2. Active packaging technology is usually required for packaging (a packaging technology that dynamically adjusts the fiber / waveguide alignment position by real-time monitoring of optical performance indicators (such as coupling efficiency and insertion loss)). The process is complex, the efficiency is low, and the packaging cost is high. Summary of the Invention

[0004] The purpose of the present invention is to provide an end face coupler structure, an end face coupler packaging structure and a packaging method thereof, so as to solve the problems existing in the above-mentioned prior art, simplify the packaging process, improve the packaging efficiency and reduce the packaging cost.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides an end face coupler structure, comprising an optical fiber array structure, a chip and a gland, wherein:

[0007] The optical fiber array structure comprises a plurality of optical fiber bodies arranged sequentially along a first direction;

[0008] The chip includes a substrate and a plurality of end-face couplers disposed on a first surface of the substrate, all of the end-face couplers being sequentially disposed along the first direction; the first surface of the substrate is provided with a plurality of positioning grooves sequentially disposed along the first direction, the positioning grooves corresponding one-to-one to the end-face couplers, and each positioning groove extending from an end proximal to the end-face coupler to a scribe line of the chip; each to-be-coupled segment of the optical fiber body is disposed within one of the positioning grooves, and the outer sidewall of each to-be-coupled segment contacts two oppositely disposed inner sidewalls of the corresponding positioning groove;

[0009] The pressure cover is arranged on the side of the segment to be coupled away from the first surface, the outer wall of the pressure cover close to the first surface is in contact with the outer side walls of all the segments to be coupled, and the pressure cover is fixedly connected to the chip; the two inner side walls of each positioning groove arranged opposite to each other and the outer wall of the pressure cover close to the first surface can limit the radial movement of the corresponding optical fiber body; each segment to be coupled is butt-coupled with the corresponding end face coupler.

[0010] Preferably, when each of the segments to be coupled contacts the two inner side walls of the corresponding positioning groove, the deviation between the core axis of each of the segments to be coupled and the waveguide center of the corresponding end face coupler is ≤2 μm.

[0011] Preferably, both inner side walls of each positioning groove are inclined planes, each inclined plane is inclined relative to the first surface, and the width of the opening end of each positioning groove is greater than the width of the bottom end of the corresponding positioning groove.

[0012] Preferably, the ratio of the vertical distance from the lower edge of the inclined plane of each positioning groove to the first surface to the opening width of each positioning groove is ≤1:2.

[0013] The present invention also provides an end face coupler packaging structure, comprising an upper cover plate, a lower cover plate and the end face coupler structure, wherein the upper cover plate and the lower cover plate are respectively arranged on both sides of the optical fiber body, and the upper cover plate and the lower cover plate can clamp the optical fiber body; the section to be coupled of each optical fiber body extends out of the upper cover plate and the lower cover plate.

[0014] Preferably, one end of the upper cover plate close to the pressure cover, one end of the lower cover plate close to the chip, one end of the pressure cover close to the upper cover plate and one end of the chip close to the lower cover plate are bonded by a sealing adhesive.

[0015] The present invention also provides an end face coupler packaging method, comprising the following steps:

[0016] S1. Obtain a chip and optical fiber array structure, wherein a surface on a side of a substrate of the chip having a scribe line is a first surface, and a first surface is provided with a plurality of end face couplers arranged sequentially along a first direction at an end of the first surface away from the scribe line; a plurality of positioning grooves are machined on the first surface of the substrate, extending from an end close to the end face coupler to an end close to the scribe line, wherein each positioning groove is arranged sequentially along the first direction and passes through an inner sidewall of the scribe line close to the end face coupler, so that each positioning groove corresponds to each end face coupler one by one;

[0017] The optical fiber array structure includes a plurality of optical fiber bodies arranged sequentially along the first direction;

[0018] S2. Disposing a gland on the side of the to-be-coupled segment 105 of the optical fiber body away from the first surface, applying pressure to the gland to press each to-be-coupled segment into one of the positioning grooves, so that two oppositely disposed inner side walls of the positioning groove are in contact with the outer side walls of the corresponding to-be-coupled segment; and docking coupling each to-be-coupled segment with the corresponding end face coupler.

[0019] Preferably, S1 further includes: processing each of the positioning grooves on the substrate through an etching process.

[0020] Preferably, S2 further includes: during the process of pressing the to-be-coupled segment into the positioning groove, monitoring the pressing pressure to keep the pressing pressure constant within a pressure range of 2-8N.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The present invention provides an end face coupler structure, an end face coupler packaging structure and a packaging method thereof, comprising an optical fiber array structure, a chip and a pressure cap. A first surface of a substrate is provided with a plurality of positioning grooves sequentially arranged along a first direction, the positioning grooves corresponding one-to-one to the end face couplers, and each positioning groove extends from an end close to the end face coupler to a dicing path of the chip. A segment to be coupled of each optical fiber body is arranged in a positioning groove, and an outer side wall of each segment to be coupled contacts two inner side walls oppositely arranged in the corresponding positioning groove. The pressure cap is arranged on a side of the segment to be coupled away from the first surface, and an outer wall of the pressure cap close to the first surface contacts the outer side walls of all segments to be coupled, and the pressure cap is fixedly connected to the chip. The two inner side walls oppositely arranged in each positioning groove and the outer wall of the pressure cap close to the first surface can limit the radial movement of the corresponding optical fiber body. Each segment to be coupled is butt-coupled with the corresponding end face coupler.

[0023] The two inner side walls of the positioning groove and the lower surface of the pressure cover can both contact the segment to be coupled and radially limit the segment to be coupled, thereby increasing the contact area and improving the positioning stability; and the positioning groove and the pressure cover cooperate to position the segment to be coupled at three circumferential positions, thereby improving the positioning accuracy. During packaging, there is no need to monitor optical performance indicators such as output light power, that is, self-alignment of the segment to be coupled can be achieved by adopting a passive coupling method, so that the fiber core axis and the center of the cantilever beam coupler waveguide are not offset, or the offset is within an allowable range, thereby simplifying the packaging process, improving the packaging efficiency, and reducing the packaging cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A front view of the end face coupler structure provided in Example 1;

[0026] Figure 2 Schematic diagram of the end face coupler structure provided in Example 1 Figure 1 ;

[0027] Figure 3 A schematic structural diagram of the optical fiber array structure provided in Example 1;

[0028] Figure 4 Schematic diagram of the chip structure provided in Example 1 Figure 1 ;

[0029] Figure 5 Schematic diagram of the chip structure provided in Example 1 Figure 2 ;

[0030] Figure 6 A schematic structural diagram of the positioning groove provided in Example 1;

[0031] Figure 7 A schematic structural diagram of the end coupler provided in Example 1;

[0032] Figure 8 Schematic diagram of the end face coupler structure provided in Example 1 Figure 2 ;

[0033] Figure 9 A schematic structural diagram of the gland provided in Example 1;

[0034] In the figure: 1000, end face coupler packaging structure; 100, optical fiber array structure; 101, upper cover plate; 102, dual-cure structural adhesive; 103, optical fiber body; 104, lower cover plate; 105, segment to be coupled;

[0035] 200, gland;

[0036] 300, chip; 310, deep etching of scribe lines; 320, positioning grooves; 330, end coupler; 331, silicon dioxide upper cladding layer; 332, silicon waveguide; 333, silicon dioxide buried oxide layer; 334, etched hollow area; 340, substrate;

[0037] 400, metal heat sink; 401, metal boss;

[0038] 500, refractive index matching sealant. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] It should be noted that in the description of the present invention, terms such as "upper", "lower", "left", "right", "inside", "outside", "front", "back", "center", "longitudinal", "lateral", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "clockwise", and "counterclockwise" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as limiting the present invention. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0041] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0042] The purpose of the present invention is to provide an end face coupler structure, an end face coupler packaging structure and a packaging method thereof, so as to solve the problems existing in the prior art, simplify the packaging process, improve the packaging efficiency and reduce the packaging cost.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] like Figures 1 to 9 As shown, this embodiment provides an end face coupler structure, including an optical fiber array structure 100, a chip 300 and a gland 200, wherein:

[0046] The optical fiber array structure 100 includes a plurality of optical fiber bodies 103 arranged sequentially along a first direction;

[0047] The chip 300 includes a substrate 340 and a plurality of end couplers 330 disposed on a first surface of the substrate 340. All end couplers 330 are arranged sequentially along a first direction. A plurality of positioning grooves 320 are disposed on the first surface of the substrate 340 and are arranged sequentially along the first direction. The positioning grooves 320 correspond one to one with the end couplers 330. Each positioning groove 320 extends from one end proximal to the end coupler 330 to the scribe line of the chip 300. The to-be-coupled segment 105 of each optical fiber body 103 is disposed within a positioning groove 320. The outer sidewall of each to-be-coupled segment 105 contacts the two opposing inner sidewalls of the corresponding positioning groove 320.

[0048] The pressure cap 200 is arranged on the side of the to-be-coupled segment 105 away from the first surface. The outer wall of the pressure cap 200 close to the first surface contacts the outer side walls of all the to-be-coupled segments 105. The pressure cap 200 is fixedly connected to the chip 300. The two inner side walls of each positioning groove 320 and the outer wall of the pressure cap 200 close to the first surface can limit the radial movement of the corresponding optical fiber body 103. Each to-be-coupled segment 105 is docked and coupled with the corresponding end face coupler 330.

[0049] The two inner side walls of the positioning groove 320 and the lower surface of the pressure cover 200 can both contact the to-be-coupled segment 105 and radially limit the to-be-coupled segment 105, thereby increasing the contact area and improving the positioning stability. Moreover, the positioning groove 320 and the pressure cover 200 cooperate to position the to-be-coupled segment 105 at three circumferential positions, thereby improving the positioning accuracy. During packaging, there is no need to monitor optical performance indicators such as the output light power. That is, self-alignment of the to-be-coupled segment 105 can be achieved by using a passive coupling method, so that the fiber core axis and the cantilever beam coupler waveguide center are not offset, or the offset is within an allowable range, thereby simplifying the packaging process, improving the packaging efficiency, and reducing the packaging cost.

[0050] In this embodiment, the pressure cap 200 can press all the segments to be coupled 105 into the corresponding positioning grooves 320. The pressure cap 200 is preferably made of glass. The pressure cap 200 is used to strengthen the connection between the segments to be coupled 105 and the substrate 340, thereby forming a stable packaging structure.

[0051] In this embodiment, the outer sidewall of each to-be-coupled segment 105 is in linear contact with the two opposite inner sidewalls of the corresponding positioning groove 320 and the outer wall of the pressure cover 200 close to the first surface to form three-point positioning to improve positioning accuracy.

[0052] In this embodiment, when each to-be-coupled segment 105 contacts the two inner sidewalls of the corresponding positioning groove 320 , the deviation between the core axis of each to-be-coupled segment 105 and the waveguide center of the corresponding end coupler 330 is ≤2 μm.

[0053] In this embodiment, both inner sidewalls of each positioning groove 320 are inclined planes, each inclined plane being inclined relative to the first surface, and the width of the opening end of each positioning groove 320 is greater than the width of the bottom end of the corresponding positioning groove 320. The length direction of each positioning groove 320 is perpendicular to the first direction.

[0054] In this embodiment, the ratio of the vertical distance from the lower edge of the inclined plane of each positioning groove 320 to the first surface to the opening width of each positioning groove 320 (the aspect ratio) is ≤ 1:2. Steep groove walls with an aspect ratio of ≤ 1:2 can provide optical self-alignment and are also easy to process.

[0055] In this embodiment, the inner bottom wall of the positioning groove 320 is preferably flat, but in actual processing, it may be formed into a curved surface. When the two inner side walls of the positioning groove 320 contact and position the optical fiber body 103, a gap is left between the inner bottom wall of the positioning groove 320 and the optical fiber body 103.

[0056] As a preferred and ideal state, the positioning groove 320 is a semicircular groove with the same diameter as the optical fiber body 103 , and the depth of the semicircular groove is half of the diameter of the optical fiber body 103 .

[0057] Example 2

[0058] This embodiment provides an end face coupler packaging structure 1000, including an upper cover plate 101, a lower cover plate 104, and the end face coupler structure of Example 1. The upper cover plate 101 and the lower cover plate 104 are respectively arranged on both sides of the optical fiber body 103, and the upper cover plate 101 and the lower cover plate 104 can clamp the optical fiber body 103; the to-be-coupled segment 105 of each optical fiber body 103 extends outside the upper cover plate 101 and the lower cover plate 104.

[0059] In this specific embodiment, one end of the upper cover plate 101 close to the pressure cover 200, one end of the lower cover plate 104 close to the chip 300, one end of the pressure cover 200 close to the upper cover plate 101 and one end of the chip 300 close to the lower cover plate 104 are bonded by a sealing adhesive. Preferably, the sealing adhesive is formed by curing the refractive index matching liquid. The use of the refractive index matching liquid eliminates the Fresnel reflection of the silica-air gap (the reflectivity is reduced from 4% to 0.2%). At the same time, the packaging structure is reinforced by controlling the modulus of the curing adhesive (1.2GPa). The upper cover plate 101 and the lower cover plate 104 can form a clamping structure, which fixes the optical fiber body 103 in the positioning groove 320 by uniform pressure, while isolating it from external environmental interference.

[0060] In this specific embodiment, the chip 300 is a silicon photonic chip; the end coupler 330 is a cantilever beam end coupler, which has the advantages of a large mode field and a large packaging alignment tolerance; and the optical fiber array structure 100 is preferably a special-shaped optical fiber array.

[0061] In this specific embodiment, a deep trench dicing lane 310 is provided on the chip 300. The deep trench dicing lane 310 serves as a stress release area during wafer cutting (dicing), which can prevent the cutting wheel from damaging the positioning groove 320 at the edge of the chip 300.

[0062] In this specific embodiment, a cantilever end face coupler is used to achieve mode field matching coupling between the silicon photonic chip 300 and the single-mode optical fiber, expand the mode field through the suspended structure, and reduce the leakage of mode light to the high-refractive-index silicon substrate.

[0063] In this specific embodiment, the cantilever beam end face coupler includes a silicon dioxide upper cladding layer 331, a silicon waveguide 332, a silicon dioxide buried oxide layer 333 (BOX layer), an etched hollow area 334, and a silicon substrate. The material of the silicon dioxide upper cladding layer 331 is PECVD-deposited SiO2 (SiO2 deposited using plasma-enhanced chemical vapor deposition technology), with a thickness of 5 μm and a refractive index of 1.44 (forming a refractive index difference with the silicon waveguide 332); the silicon dioxide upper cladding layer 331 is used to cover the silicon waveguide 332, forming the upper boundary of the optical waveguide transmission.

[0064] The cross-sectional dimensions of the silicon waveguide 332 are: width 500 nm × height 220 nm (standard SOI waveguide dimensions); mode field diameter: 7 to 10 μm (mode field distribution is optimized through edge rounding to match the 8 to 10 μm mode field of a single-mode optical fiber).

[0065] The material of the silicon dioxide buried oxide layer 333 (BOX layer) is SiO2, with a thickness of 2 to 3 μm. It serves as an isolation layer between the silicon waveguide 332 and the substrate 340 and has a refractive index of 1.44. It achieves optical confinement of light field leakage and electrical isolation of the silicon waveguide 332.

[0066] The size of the etched hollow area 334 is through the BOX layer and part of the silicon substrate. The process is to remove the SiO2 below the silicon waveguide 332 and the 10-50 μm thick silicon substrate by dry etching (SF6 / O2 mixed gas). The function is to form a suspended structure of the silicon waveguide 332 to reduce the absorption of the evanescent field by the silicon substrate.

[0067] In this specific embodiment, the coupled segment 105 is a bare fiber with an outer diameter of 125 μm ± 1 μm (compliant with ITU-T G.652 standard), with the coating removed (exposing the pure silica core / cladding); a core diameter of 9 μm (single-mode fiber) and a mode field diameter of 8.2 μm @ 1550 nm; an alignment mechanism: after embedding in the positioning groove 320, the vertical / horizontal deviation between the center of the fiber core and the center of the silicon waveguide 332 is ≤ 2 μm (guaranteed by the positioning groove 320 constraint and the processing accuracy of the chip 300); end face processing: the fiber end face remains flat (not angle polished), with a spacing of 0 to 2 μm from the coupler light output end face, and a refractive index matching liquid (Refractive Index, RI = 1.44) is used to eliminate air gap reflections (reflectivity is reduced from 4% to 0.2%).

[0068] In this specific embodiment, the upper cover plate 101 is made of borosilicate glass (model: Schott AF32, with a thermal expansion coefficient of 3.2 ppm / °C (temperature range of 20-300°C), matching the optical fiber), with a thickness of 0.6 mm.

[0069] In this specific embodiment, the upper cover plate 101 is arranged on the upper right side of the lower cover plate 104, and a dual-cure structural adhesive 102 (Dual-Cure Adhesive) is arranged on the upper left side of the lower cover plate 104. After curing, a rigid connection of "upper cover plate 101-optical fiber-lower cover plate 104" is formed, while buffering thermal mechanical stress.

[0070] Key design: The glue layer thickness is controlled at 20-30 μm (limited by the cover plate positioning column height) to prevent excessive glue from seeping into the positioning groove 320 and affecting the optical fiber alignment.

[0071] In this specific embodiment, the optical fiber body 103 is a single-mode optical fiber (SMF-28e+) with parameter specifications: core / cladding: 9 / 125 μm (G.652D standard), mode field diameter: 8.2 μm@1550 nm (matching the silicon waveguide 332 mode field).

[0072] In this specific embodiment, a plurality of V-shaped grooves are provided on the lower cover plate 104 . The lower cover plate 104 serves as a pre-positioning carrier of the optical fiber array structure 100 , and batch alignment of multi-channel optical fibers is achieved through the precise V-shaped grooves.

[0073] In this specific embodiment, the function of the glass clamp 200 (Glass Clamp) is to embed the bare optical fiber into the positioning groove 320 through the controllable pressure of the pressure head. The pressure needs to be monitored in real time during the pressing process to avoid over-pressure damage. Pressure range: 2-8N (based on the optical fiber compressive strength of 12N / 125μm, with a 30% safety margin), resolution: 0.1N. An array of silicone pads (Shore hardness: 60A) is provided on the pressure head. The contact area between the pressure head and the glass clamp 200 is 1mm×1mm to ensure uniform pressure distribution (pressing pressure deviation <5%). A piezoresistive sensor (sensitivity 1mV / V / MPa) is integrated on the pressure head. When the pressure is greater than 8N, automatic pressure relief is triggered to prevent the optical fiber from breaking (failure threshold 12N), thereby realizing real-time pressure control.

[0074] In this embodiment, the thermally matched metal heat sink 400 is made of copper, iron, aluminum, or Kovar alloy. A metal boss 401 is located on the underside of the chip 300. The chip 300 is attached to the boss 401, with the end coupling portion slightly offset to the left by 1-0.5 mm to ensure proper contact between the fiber array structure 100 and the boss. The height of the boss 401 should be neither too high nor too low. The distance between the lower cover 104 and the metal heat sink 400 is 0.1-2 mm.

[0075] In this specific embodiment, the index-matched encapsulant 500 (index-matched encapsulant): a refractive index matching liquid (epoxy resin glue, refractive index: 1.442@1550nm, which matches the refractive index of silicon dioxide in the infrared band (such as the 1550nm wavelength commonly used in communications) of approximately 1.44 and the refractive index of optical fiber ≈1.44), is used to fix the chip 300 and reinforce the glass cover 200, optical fiber array, and metal heat sink 400 to form a stable packaging structure.

[0076] In the present embodiment, h1: the height of the dicing lane notch of the silicon optical chip 300 is greater than half the diameter of the optical fiber (125 μm), and is generally about 100 μm; h2: the distance between the optical fiber array structure 100 and the metal heat sink 400 is generally greater than 0.1 mm, and is between 0.1-2 mm; w1: the width of the dicing lane notch of the silicon optical chip 300 is about 50-100 μm; w2: the distance between the outer sidewall of the substrate 340 away from the end face coupler 330 and the end face of the lower cover plate 104 close to the chip 300 is greater than 0, and is actually as small as possible. However, due to the machining precision of the optical fiber array, it is generally in the range of 0.1-0.3 mm. The length of the to-be-coupled section 105 is greater than the sum of the length of the positioning groove 320 and the length of the dicing lane groove structure on the chip 300. The length of the reinforcing gland 200 is greater than the width of the array coupler of the chip 300, such as the distance between the end face couplers 330 is 127 μm, and the array coupler is 12 channels, and the width of the array coupler is about 1.4 mm.

[0077] Embodiment 3

[0078] The present embodiment provides a method for packaging an end face coupler structure, comprising the following steps:

[0079] S1, obtaining a chip 300 and an optical fiber array structure 100, the surface of one side of the substrate 340 of the chip 300 is provided with a first surface, and the first surface is provided with a plurality of end face couplers 330 arranged in sequence along the first direction away from one end of the dicing lane; a plurality of positioning grooves 320 extending from one end close to the end face coupler 330 to one end close to the dicing lane are machined on the first surface of the substrate 340, and each positioning groove 320 is arranged in sequence along the first direction and penetrates the inner sidewall close to the end face coupler 330 of the dicing lane, so that the positioning groove 320 corresponds to the end face coupler 330 one by one;

[0080] The optical fiber array structure 100 comprises a plurality of optical fiber bodies 103 arranged in sequence along the first direction;

[0081] S2, a gland 200 is arranged on the side of the to-be-coupled section 105 of the optical fiber body 103 away from the first surface, and a pressure is applied to the gland 200 to press each to-be-coupled section 105 into one positioning groove 320, so that the two oppositely arranged inner sidewalls of the positioning groove 320 are in contact with the outer sidewall of the corresponding to-be-coupled section 105; and each to-be-coupled section 105 is in butt coupling with the corresponding end face coupler 330.

[0082] In this specific embodiment, S2 also includes: making the end face of the chip 300 close to the dicing street and the cover plate assembly (upper cover plate 101 and lower cover plate 104) close to one end of the segment to be coupled 105 relative to each other, applying pressure to the pressure cover 200 to press each segment to be coupled 105 into a positioning groove 320, and completing the pressing of each segment to be coupled 105; thereafter, first fixing the pressure cover 200 on the base 340, and then docking coupling each segment to be coupled 105 with the corresponding end face coupler 330.

[0083] In this specific embodiment, S1 further includes: processing each positioning groove 320 on the substrate 340 through an etching process.

[0084] In this specific embodiment, S2 further includes: during the process of pressing the to-be-coupled segment 105 into the positioning groove 320 , monitoring the pressing pressure to keep the pressing pressure constant within a pressure range of 2-8N.

[0085] In this embodiment, a precision etching step is added during the processing of the end coupler 330. By adjusting the etching depth-to-width ratio and inclination, a positioning groove 320 suitable for aligning the bare fiber with the end coupler 330 is obtained. The length of the positioning groove 320 is 1-5 mm (generally around 2 mm). The chip 300 cut from the wafer is then attached to the metal boss 401 of the metal heat sink 400 using conductive silver glue. The end face of the chip 300 near the lower end cap protrudes outward to prevent the fiber array structure 100 from tightly fitting with the chip 300. The fiber array structure 100 is then aligned with the end coupler 330 so that the segment to be coupled 105 (bare fiber) is completely aligned with the cantilever beam coupler. A pressure cap 200 is then used to compact the segment to be coupled 105 so that it fits into the positioning groove 320. The design of the positioning groove 320 is preferably such that, when the positioning groove 320 and the coupled segment 105 make tangential contact at three points, the core of the optical fiber body 103 is aligned precisely with the center of the cantilever beam coupler. High-precision machining of the chip 300 ensures precise docking. The optical fiber array, gland 200, chip 300, and metal heat sink 400 are then cured using a refractive index matching liquid. Once cured, the refractive index matching liquid forms a sealant, ultimately creating a stable package structure.

[0086] In this specific embodiment, by controlling the aspect ratio and tilt angle of reactive ion etching (RIE), a high-precision positioning groove 320 is prepared on the end face of the chip 300: the length is 2mm; the angle between the plane of the two inner sidewalls of the positioning groove 320 and the horizontal plane of the chip is 60°, which is calculated based on the fiber diameter to ensure that both inner sidewalls are tangent to the fiber body 103; the minimum depth of the positioning groove 320 is 62.5μm (equal to the radius of the fiber body 103, achieving semi-embedded fixation of the fiber body 103). This structural design enables the positioning groove 320 to form a two-point tangent positioning with a bare fiber with a diameter of 125μm, forming a three-point positioning system with the pressure cap 200, capable of achieving a deviation of ≤2μm between the fiber axis and the cantilever beam coupler waveguide center, enabling self-alignment of the coupled segment 105, and enabling "blind plug-in" alignment assembly.

[0087] In this specific embodiment, during the chip 300 mounting process, conductive silver glue is used to adhere the cut chip 300 to the metal boss 401 of the gold-plated metal heat sink 400. The first end face of the chip 300 is intentionally left with an overhang of 0.1 to 0.5 mm relative to the metal boss 401 to prevent glue overflow from the bottom surface from blocking the optical fiber array, making it impossible for the optical fiber array structure 100 to be tightly connected to the chip end face.

[0088] In this specific embodiment, the typical spacing of the pre-processed bare optical fiber array is 127μm±0.5μm, and the end face inclination angle is 0°. At this time, a gap of 0 to 2μm is reserved between the tip of the optical fiber and the cantilever beam coupler to avoid contact stress from damaging the coupler cantilever structure. Then, a customized pressure cap 200 (thickness of 0.5-1mm) is covered, and the optical fiber array is pressed into the positioning groove 320 with a pressure of 2 to 8N using a precision press head, and then the UV glue is cured. The curing process is implemented in two steps: first, a refractive index matching liquid (refractive index RI = 1.44, matching silica glass) is dripped on the edge of the pressure cap 200, and pre-cured by ultraviolet light (intensity of 500mW / cm 2 , curing time is 5min); UV curing glue is then injected to fill the gaps between the optical fiber, chip 300 and metal heat sink 400. After UV pre-curing, it is thermally cured at 85°C for more than 2 hours to form a stable structure. This process utilizes the geometric positioning accuracy of the positioning groove 320 (±0.5μm) and the batch processing consistency of the chip 300 (±0.1μm positioning accuracy of the chip 300 processing) to reduce the alignment accuracy requirements of the optical fiber array structure 100 and the end face coupler 330, and can achieve an alignment tolerance of ±2μm, which can stabilize the coupling loss within 1.0dB, and does not require the power monitoring link of the traditional active packaging. This embodiment simplifies the packaging process through the dual design of the positioning groove 320 design and material compensation reinforcement, shortening the traditional active packaging process that takes 1 to 2 hours to 10-30 minutes, providing an alternative for low-cost, rapid large-scale production.

[0089] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. An end coupler structure, characterized in that: It includes an optical fiber array structure, a chip and a gland, wherein: The optical fiber array structure comprises a plurality of optical fiber bodies arranged sequentially along a first direction; The chip includes a substrate and a plurality of end-face couplers disposed on a first surface of the substrate, all of the end-face couplers being sequentially disposed along the first direction; the first surface of the substrate is provided with a plurality of positioning grooves sequentially disposed along the first direction, the positioning grooves corresponding one-to-one to the end-face couplers, and each positioning groove extending from an end proximal to the end-face coupler to a scribe line of the chip; each to-be-coupled segment of the optical fiber body is disposed within one of the positioning grooves, and the outer sidewall of each to-be-coupled segment contacts two oppositely disposed inner sidewalls of the corresponding positioning groove; The pressure cover is arranged on the side of the segment to be coupled away from the first surface, the outer wall of the pressure cover close to the first surface is in contact with the outer side walls of all the segments to be coupled, and the pressure cover is fixedly connected to the chip; the two inner side walls of each positioning groove arranged opposite to each other and the outer wall of the pressure cover close to the first surface can limit the radial movement of the corresponding optical fiber body; each segment to be coupled is butt-coupled with the corresponding end face coupler.

2. The end coupler structure according to claim 1, wherein: When each of the segments to be coupled contacts the two inner side walls of the corresponding positioning groove, the deviation between the core axis of each of the segments to be coupled and the waveguide center of the corresponding end face coupler is ≤2 μm.

3. The end coupler structure according to claim 1, wherein: Both inner side walls of each positioning groove are inclined planes, each inclined plane is inclined relative to the first surface, and the width of the opening end of each positioning groove is greater than the width of the bottom end of the corresponding positioning groove.

4. The end coupler structure according to claim 3, wherein: The ratio of the vertical distance from the lower edge of the inclined plane of each positioning groove to the first surface to the opening width of each positioning groove is ≤1:

2.

5. An end face coupler packaging structure, characterized in that: It comprises an upper cover plate, a lower cover plate and the end face coupler structure according to any one of claims 1 to 4, wherein the upper cover plate and the lower cover plate are respectively arranged on both sides of the optical fiber body, and the upper cover plate and the lower cover plate can clamp the optical fiber body; the section to be coupled of each optical fiber body extends out of the upper cover plate and the lower cover plate.

6. The end coupler structure according to claim 5, characterized in that: One end of the upper cover plate close to the pressure cover, one end of the lower cover plate close to the chip, one end of the pressure cover close to the upper cover plate and one end of the chip close to the lower cover plate are bonded together by a sealing adhesive.

7. A method for packaging an end coupler, characterized in that: The steps include: S1. Obtain a chip and optical fiber array structure, wherein a surface on a side of a substrate of the chip having a scribe line is a first surface, and a first surface is provided with a plurality of end face couplers arranged sequentially along a first direction at an end of the first surface away from the scribe line; a plurality of positioning grooves are machined on the first surface of the substrate, extending from an end close to the end face coupler to an end close to the scribe line, wherein each positioning groove is arranged sequentially along the first direction and passes through an inner sidewall of the scribe line close to the end face coupler, so that each positioning groove corresponds to each end face coupler one by one; The optical fiber array structure includes a plurality of optical fiber bodies arranged sequentially along the first direction; S2. Disposing a gland on the side of the to-be-coupled segment 105 of the optical fiber body away from the first surface, applying pressure to the gland to press each to-be-coupled segment into one of the positioning grooves, so that two oppositely disposed inner side walls of the positioning groove are in contact with the outer side walls of the corresponding to-be-coupled segment; and docking coupling each to-be-coupled segment with the corresponding end face coupler.

8. The end face coupler packaging method according to claim 7, wherein: S1 also includes: processing each of the positioning grooves on the substrate through an etching process.

9. The end face coupler packaging method according to claim 7, wherein: S2 further includes: during the process of pressing the to-be-coupled segment into the positioning groove, monitoring the pressing pressure to keep the pressing pressure constant within a pressure range of 2-8N.

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