CN1346993A - Locating module for optical fibre array - Google Patents

Abstract

An optical fiber array positioning component belongs to passive devices in optical communication technology, and particularly relates to an optical fiber array component for input or output parallel coupling interfaces of various one-dimensional and two-dimensional array devices. The present invention solves the problem of accurate positioning of the optical fiber array under the condition of low cost and high precision requirements. The present invention is composed of upper and lower substrates and optical fibers located therebetween. In the etching groove, the width between the lines on both sides of the surface is smaller than the diameter of the fiber core diameter, and the etching depth is greater than the height of the arc section of the fiber core diameter located in the etching groove. The invention eliminates the influence of various uneven factors in the forming process of the concave groove when the inner surface of the concave groove is used to position the optical fiber, the positioning accuracy can reach 0.1 μm, and it can also be used with the folding lens positioning assembly of the same structure and the vertical cavity surface emission Lasers are integrated on a base substrate, which greatly improves the yield, efficiency and high-quality optical performance of optoelectronic devices in packaging technology.

Description

Fiber Array Positioning Components

technical field

The invention belongs to passive devices in the optical communication technology, in particular to an optical fiber array assembly for input or output parallel coupling interfaces of various one-dimensional or two-dimensional array devices in the optical communication.

Background technique

In recent years, due to the rapid development of optical communication, a large number of new active devices and passive devices used in DWDM optical communication networks have emerged. Various devices such as planar waveguide chips, micro-opto-electromechanical switch MEMS chips, and surface-emitting laser array VCSEL chips have been successfully developed. To make the above chip into a practical device, it is necessary to have a high-precision fiber array component as the input or output coupling interface of the device. Packaging technology is used to strictly and accurately align each optical path in the above chip with the corresponding optical fiber in the fiber array component. Accurate, fixed, and make stable and practical devices during the growth period to ensure the excellent optical characteristics of the device. Meanwhile, the packaging technology of the above-mentioned devices is the most labor-intensive process, which is one of the highest parts in the device cost. Therefore, providing high-precision optical fiber array components is one of the most critical technologies to ensure high-quality optical characteristics of optoelectronic devices, improve packaging process efficiency, and reduce device costs. At the same time, in many devices, a high-efficiency parallel collimated beam array is required to convert the light from the fiber array into a parallel collimated beam array. In addition to the high-precision fiber array, a high-precision positioning deflection lens array.

At present, the optical fiber array is made by etching some parallel V-shaped grooves on the silicon wafer with a specific crystal orientation, inserting the optical fibers into the V-shaped grooves, and using the inner surface of the V-shaped grooves as the surface for positioning each optical fiber to make an optical fiber array component, as shown in the figure 1. (A) and (B) are US patent 5,656,120, (C) Chinese patent 00101007.7. There are also concave grooves engraved on the substrate, and the inner surface of the concave groove is used as the surface for positioning each optical fiber to make an optical fiber array assembly, see FIG. 1(D), US Patent 6,706,371. Etching V-shaped grooves on the surface of the substrate can ensure sufficient precision in the positioning of the fiber array, but because the substrate uses a silicon wafer with a specific crystal orientation, the cost is expensive. The optical fiber is embedded in the concave groove on the surface of the substrate for positioning. The positioning accuracy of the optical fiber is related to the depth of the concave groove and the precision of the inner surface forming. The deeper the concave groove, the uniform the width between the lines on both sides of the concave groove on the substrate surface. Therefore, it is difficult to ensure the accuracy of positioning the optical fiber with the inner surface of the concave groove, and the deeper the concave groove is, the more difficult it is to ensure the precise positioning of the optical fiber.

Contents of the invention

The optical fiber array positioning component of the present invention solves the problem of accurate positioning of a one-dimensional or two-dimensional optical fiber array under the condition of low cost and high precision requirements, and can also solve the problem of accurate positioning of a folding lens array.

The optical fiber array positioning assembly of the present invention is composed of upper and lower substrates and optical fibers between the upper and lower substrates. One or both of the upper and lower substrates have etched grooves on the surface for optical fiber positioning. It is characterized in that the etching groove is a concave groove, the width between the lines on both sides of the etching groove on the substrate surface is smaller than the diameter of the fiber core diameter, and the etching depth of the etching groove is greater than the arc section of the fiber core diameter located in the etching groove high.

The optical fiber array positioning assembly is further characterized in that one end of the upper and lower substrates is processed into a wedge angle to accommodate the optical fiber interface where the optical fiber microstrip strips the cladding.

In the optical fiber array positioning assembly, the etched grooves can be arranged in parallel on one or both surfaces of the upper and lower substrates, and the distance between adjacent etched grooves can be equal or unequal.

In the optical fiber array positioning component, the etched grooves can also be arranged radially on one or both surfaces of the upper and lower substrates.

In the optical fiber array positioning assembly, one of the upper and lower substrates may have concave etching grooves on both sides to form a two-dimensional optical fiber array positioning assembly.

The optical fiber array positioning assembly, the optical fiber array positioning assembly and the folding lens array positioning assembly can be placed on the same base substrate, and the folding lens array positioning assembly consists of upper and lower substrates and a Composed of a cylindrical refractive lens, one or both of the upper and lower substrates have concave etched grooves on the surface, and one of the upper and lower substrates can also have concave etched grooves on both sides, and the line between the two sides of the surface The width between the gaps is smaller than the diameter of the refraction lens, the etching depth of the etching groove is greater than the arc height of the part of the refraction lens located in the etching groove, and the core diameter of each optical fiber in the optical fiber array positioning component and each fiber core diameter in the refraction lens array positioning component The folding lenses are coaxially connected to form a parallel collimated beam array assembly.

The optical fiber array positioning assembly, the optical fiber array positioning assembly can also be placed on the same base substrate as the vertical cavity surface emitting laser, the vertical cavity surface emitting laser pixels are arranged in a one-dimensional or two-dimensional array, and each pixel is aligned Each fiber core in the fiber array positioning component is directly coupled or the laser beam emitted by each pixel is coupled to each fiber core in the fiber array positioning component through a total reflection mirror.

The invention adopts the lines on both sides of the etched groove on the surface of the substrate to position each optical fiber or folding lens to form an optical fiber array or a folding lens array. Because the surface processing precision of substrates such as various glasses, silicon wafers, and lithium niobate is very high, the accuracy of the line width of the photolithography mask is generally less than 0.1 μm. Using the lines on both sides of the etching groove to position the optical fiber requires etching grooves. The depth is much smaller than the depth of the concave groove when the optical fiber is positioned on the inner surface of the concave groove. Therefore, after the surface of the substrate is photolithographically patterned, the reactive ions are vertically bombarded to form concave grooves, and the width of the lines on both sides of the grooves is basically consistent with the width precision of the mask plate lines. Use the lines on both sides of the etched groove on the surface of the substrate to position the optical fiber or the folding lens, eliminating the influence of various uneven factors introduced during the forming process of the concave groove when positioning the optical fiber or the folding lens on the inner surface of the concave groove . Therefore, the positioning assembly of the optical fiber array and the refraction lens proposed by the present invention has a low substrate cost, and the positioning accuracy of each optical fiber or refraction lens can reach 0.1 μm. The yield, efficiency and high-quality optical performance of related optoelectronic devices in packaging technology can be greatly improved.

Description of drawings

Figure 1 (A) ~ (D) is a schematic diagram of the prior art of fiber array positioning components, where (A) and (B) are US Patent 5,656120; (C) is Chinese Patent 00101007.7; (D) is US Patent 6, 706371.

2(A)-(C) are schematic cross-sectional views of the present invention.

Fig. 3(a) is a schematic longitudinal sectional view of the optical fiber array assembly of the present invention.

Fig. 3(b) is a schematic longitudinal sectional view of the folding lens array assembly.

Fig. 4 is a schematic diagram of an optical fiber array positioning assembly of the present invention.

5(a)-(f) show the process flow of etching concave grooves on the substrate.

Fig. 6 is a schematic diagram of positioning components of a two-dimensional optical fiber array and a folding lens array.

7 is a schematic diagram of a parallel collimated beam array assembly formed by an optical fiber array positioning assembly and a folding lens positioning assembly.

8(A)-(B) show the situation that the present invention is used in the output coupling component of the vertical cavity surface emitting laser one-dimensional line array.

Fig. 8(C) is a schematic diagram of the integration of the fiber array positioning component and the vertical cavity surface emitting laser on the same base substrate.

9(A)-(B) show the situation that the present invention is used in the output coupling component of the vertical cavity surface emitting laser two-dimensional line array.

Detailed ways

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

The components of the invention can be processed into high-precision substrates by using various glasses, and the processing is convenient and the cost is low. Fig. 2 represents the cross section of various forms of assembly of the present invention, and wherein (A) is that lower substrate surface is etched with concave groove; (B) is that upper substrate surface is etched with concave groove; (C) is upper, Concave grooves are etched on the surface of the lower substrate. The width of the lines on both sides of the groove surface should be smaller than the core diameter of the optical fiber or the diameter of the folding lens. The etching depth is related to the width of the groove. When the optical fiber or the folding lens is placed on the two sides of the surface groove, it is better that the surface of the optical fiber or the folding lens cannot contact the inner surface of the groove. The position of each optical fiber or folding lens, that is to say, the position of each concave groove, can be determined according to the needs of the optoelectronic device. Some are equidistant parallel grooves, some are parallel grooves with non-uniform spacing, and some are distributed in a fan shape or other shapes.

Fig. 3 (a) shows the longitudinal section of the optical fiber array positioning assembly of the present invention, and one end of the substrate is processed into a wedge angle, and the angle and length of the wedge angle can embed the cladding fiber part behind the exposed optical fiber in it, After glue injection in the opening angle space, it can protect the exposed fiber tail. In the figure, 1 is the fiber core, 2 is the lower substrate with concave grooves, 3 is the upper substrate, and 4 is the glue injection layer, which is filled with the upper and lower sides. The gap between the substrate and the optical fiber solidifies the substrate optical fiber into a whole, and 5 is the cladding of the optical fiber. Fig. 3 (b) is a vertical cross-sectional view of the folding lens array of the present invention, 6 is the folding lens, and the glue injection layer fills the gap between the upper and lower substrates and the folding lens, and solidifies them into a whole.

Fig. 4 shows a kind of optical fiber array positioning assembly of the present invention, and its manufacturing process is as follows, firstly strip off the cladding of the front section of each optical fiber, the optical fiber core 1 is exposed, and cleans for future use. The substrate 2 with the etched groove is placed on a large substrate and under a microscope, so that the surface of the etched groove can be clearly observed. Accurately arrange the exposed parts of the optical fibers one by one on both sides or in the etching groove on the surface of the substrate. Note that for the optical fiber with cladding 5, its core and cladding are stripped, and the interface is placed in the optical wedge at the end of the substrate layer. When discharging each optical fiber, before and after the lower substrate, on the large substrate, two substrates with a slightly thinner thickness than the substrate 2 can be placed. Put double-sided tape on it. When discharging each optical fiber, it temporarily acts as a fixation. After all the optical fibers are arranged, the upper substrate 3 is covered and pressed tightly, the space between the upper and lower substrates is cured by the glue injection layer 4, and the surface of the port of the optical fiber array component is polished. It is also possible to discharge the left and right optical fibers first, cover the upper substrate and press it tightly, inject a little glue from both sides to fix the upper and lower substrates, and insert the other intermediate optical fibers into the corresponding etching groove positions one by one, and then, in the upper and lower The space between the substrates is injected and solidified, and then the surface of the port of the optical fiber array component is polished. If the end of the optical fiber has been processed into other shapes with molten spherical optical fiber or the end of the optical fiber, the front ends of the upper and lower substrates are also processed into wedge angles like the rear ends. The bare fused spherical or other shaped optical fiber head is placed in the optical wedge space at the front end of the substrate for protection.

Selecting ultraviolet glass or a material with a small expansion coefficient as the substrate has the advantage of good stability. This kind of substrate can be prepared with a mask pattern, and a metal film is coated on the processed substrate as a masking layer. The thickness is determined by the depth of the etching groove, and then photolithography-reactive ion etching is used. method, etching to form concave grooves, and its specific process flow is shown in FIG. 5 . Figure 5(a) shows the substrate. Firstly, according to the needs of the distribution position of the optical fiber emitted by the device, the mask pattern is made, and according to the process flow of photolithography-reactive ion etching, a thicker masking layer is made on the upper surface of the substrate. , see Fig. 5(b), photoetching etch exposes the surface to be etched with concave grooves, see Fig. 5(c). In the reactive ion etching process, vertical bombardment with ions is shown in Figure 5(d). A concave groove of a certain depth required is formed on the surface of the substrate, as shown in FIG. 5( e ). After removing the masking layer, the desired substrate with concave groove distribution on the surface is formed, as shown in Fig. 5(f). The process of making concave grooves on the substrate, different materials can adopt different processes, but the width between the lines on both sides of the etching groove on the substrate surface must be kept, and it is appropriate to be consistent with the pattern accuracy of the mask plate. The width of the lines on both sides of the groove surface b ₁ b ₂ , b ₃ b ₄ , b ₅ b ₆ , ... b _n-1 b _n , all should be smaller than the core diameter of the optical fiber or the diameter of the refraction lens.

The lines on both sides of the etching groove on the surface of the substrate position the optical fiber or the folding lens, which can be developed into a two-dimensional optical fiber array or a folding lens positioning assembly, as shown in FIG. 6 . It is made up of the middle substrate 9 and the substrates 7 and 8 on the upper and lower sides. The process of the substrate with concave etching grooves on both sides is as follows. The thickness and surface size of the substrate are processed according to the needs. For the etching of the concave grooves on both surfaces of the substrate, a mask plate can be used, and an infrared double-sided alignment exposure machine can be used. Lithograph patterns on both surfaces respectively, and then according to the process flow in Figure 5, use the reactive ion etching method to respectively etch concave grooves on both surfaces of the substrate, and then assemble one side of the optical fiber or folding lens according to the process in Figure 4, The glue is injected and cured, and then the optical fiber or folding lens is assembled on the other side of the substrate, and the glue is injected and cured to form a two-dimensional optical fiber array.

FIG. 7 is a parallel collimated beam array assembly formed by placing the optical fiber array and the refraction lens array on a bottom substrate 10, and placing each optical fiber and each refraction lens completely coaxially. Because the positioning accuracy of the optical fiber array and the refraction lens array can reach 0.1 μm, each optical fiber and each refraction lens between the two can be completely coaxially arranged to form a parallel collimated beam array assembly.

Use the lines on both sides of the etched groove on the surface of the substrate to locate various uniform and equal spacing, non-uniform spacing and other distributions of high-precision one-dimensional and two-dimensional multimode fiber array components, which can be used for one-dimensional lines of vertical cavity surface emitting lasers (VCSEL) output coupling components for arrays and 2D arrays. Vertical Cavity Surface Emitting Laser (VCSEL) is a complete planar growth process. Thousands of VCSEL pixels are arranged on a VCSEL chip. In general edge-emitting semiconductor lasers, the beam spot emits laser light from the side parallel to the surface. When the laser is emitted and output, due to the limitation of the upper and lower surfaces, the laser beam spot is in the shape of a long ellipse, which is difficult to couple to the fiber core. The VCSEL laser beam is emitted perpendicular to the surface, and the laser beam spot is in a circular symmetrical shape, which is easy to couple into the fiber core. If the VCSEL chip is cut into strips, the VCSEL pixels are arranged in a one-dimensional array, and the standard spacing is 250 μm. If the spacing between the fibers in the one-dimensional multimode fiber Template lithography process, the error of the pitch is 0.1μm, it is easy to strictly align each VCSEL pixel with an optical fiber, if they can be placed very close, the laser emitted by each VCSEL pixel is directly coupled to each The efficiency of a multimode fiber can reach more than 90%. If there is a certain distance between them, a microlens array needs to be placed between them, and the VCSEL laser beam needs to be collimated before being coupled into each optical fiber. FIG. 8(A) is a schematic diagram of a one-dimensional linear array VCSEL laser directly coupled to the core diameter 1 of a multimode optical fiber. 11 is the laser pixel in the VCSEL chip, 12 is the IC chip driving the laser pixel, 13 is the substrate for placing the VCSEL chip and the IC chip, and 14 is the bottom substrate for placing the entire coupling assembly. FIG. 8(B) shows that the one-dimensional linear array VCSEL laser beams are totally reflected by the total reflection mirror 15, and then respectively coupled into each multimode fiber in the multimode fiber ribbon. Fig. 8(C) is a schematic diagram of the integration of the fiber array positioning component and the VCSEL chip. Fig. 9 (A) and (B) respectively are two-dimensional VCSEL laser array 16 directly coupled to two-dimensional fiber array, and two-dimensional VCSEL laser array 16 is totally reflected by total reflection mirror 15 and then respectively coupled to two-dimensional optical fiber array The schematic diagram in the array. The high-precision optical fiber array component of the present invention can also be applied to various types of planar optical waveguide chips and micro-optical electromechanical MEMS chip input and output interface coupling components, and can be developed into various dense wavelength division multiplexing/demultiplexing devices, optical switching switches and optical cross-connect devices.

Claims (10)

1. optical fibre array positioning assembly, constitute by upper and lower substrate and the optical fiber between upper and lower substrate, there is the etching groove on a slice in the upper and lower substrate or two surfaces, be used for fiber orientation, it is characterized in that described etching groove is a Baltimore groove, width is less than the diameter of optical fiber core diameter between substrate surface etching groove two side lines, and the groove etched degree of depth of etching is positioned at the arc section height of etching groove part greater than the optical fiber core diameter.

2. optical fibre array positioning assembly as claimed in claim 1 is characterized in that an end of upper and lower substrate all is processed into the angle of wedge, peels off the optical fiber interface place of covering with the little band of receiving optical fiber.

3. optical fibre array positioning assembly as claimed in claim 1 or 2 is characterized in that etching groove a slice or two surfaces in upper and lower substrate are arranged in parallel, and the adjacent etched separation can equate, also can be unequal.

4. optical fibre array positioning assembly as claimed in claim 1 or 2 is characterized in that etching groove a slice or two surfaces in upper and lower substrate are radial arrangement.

5. optical fibre array positioning assembly as claimed in claim 3 is characterized in that a slice double-sided belt spill etching groove in the upper and lower substrate, constitutes the 2-D optical fibre array positioning component.

6. optical fibre array positioning assembly as claimed in claim 4 is characterized in that a slice double-sided belt spill etching groove in the upper and lower substrate, constitutes the 2-D optical fibre array positioning component.

7. optical fibre array positioning assembly as claimed in claim 3, it is characterized in that this optical fibre array positioning assembly and sell off the lens arra positioning component placing on the same bottom substrate, sell off the lens arra positioning component by last, subtegulum and being positioned at, the cylindrical lens of selling off between the subtegulum constitute, on, there is spill etching groove on a slice in the subtegulum or two surfaces, width is less than the diameter of selling off lens between its surperficial two side lines, the groove etched degree of depth of etching is greater than selling off the crown height that lens are positioned at etching groove part, each bar optical fiber core diameter and sell off in the lens arra positioning component each and sell off lens and be coaxial docking in the optical fibre array positioning assembly forms parallel collimated light beam array component.

8. optical fibre array positioning assembly as claimed in claim 5, it is characterized in that this optical fibre array positioning assembly and sell off the lens arra positioning component placing on the same bottom substrate, sell off the lens arra positioning component by last, subtegulum and being positioned at, the cylindrical lens of selling off between the subtegulum constitute, on, a slice in the subtegulum is two-sided spill etching groove, width is less than the diameter of selling off lens between its surperficial two side lines, the groove etched degree of depth of etching is greater than selling off the crown height that lens are positioned at etching groove part, each bar optical fiber core diameter and sell off in the lens arra positioning component each and sell off lens and be coaxial docking in the optical fibre array positioning assembly forms parallel collimated light beam array component.

9. optical fibre array positioning assembly as claimed in claim 3, it is characterized in that this optical fibre array positioning assembly and vertical cavity surface emitting laser place on the same bottom substrate, the vertical cavity surface emitting laser picture dot is that one dimension or two-dimensional array are arranged, each picture dot aim in optical fibre array positioning assembly each bar fiber cores footpath directly laser beam of sending of coupling or each picture dot be coupled to again in each bar optical fiber core diameter in the optical fibre array positioning assembly through completely reflecting mirror.

10. optical fibre array positioning assembly as claimed in claim 5, it is characterized in that this optical fibre array positioning assembly and vertical cavity surface emitting laser place on the same bottom substrate, the vertical cavity surface emitting laser picture dot is that one dimension or two-dimensional array are arranged, each picture dot aim in optical fibre array positioning assembly each bar fiber cores footpath directly laser beam of sending of coupling or each picture dot be coupled to again in each bar optical fiber core diameter in the optical fibre array positioning assembly through completely reflecting mirror.

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