CN102902024A - Method for realizing optical coupling of multi-core fiber and photoelectron chip array - Google Patents

Abstract

The invention relates to a method for realizing the optical coupling between a multi-core optical fiber and an optoelectronic chip array, comprising: fixing the spacer in the shell, and then putting solder into the small groove on the spacer; placing the optoelectronic chip in the corresponding In the groove, melt the solder to fix the optoelectronic chip, and then complete the electrical connection of the optoelectronic chip by wire bonding; align the end face of the multilayer waveguide with the light emitting surface of the pad, and fix the multilayer waveguide; adjust and fix the lens group The position of the multi-core fiber is then aligned and fixed to realize optical coupling between the multi-core fiber and the optoelectronic chip array. The invention uses a multi-layer waveguide to convert the mode spots arranged symmetrically in the center of the multi-core optical fiber into the mode spots arranged in a straight line, which has the advantages of small size, suitable for packaging in a tube shell, etc. application.

Description

Method for realizing optical coupling between multi-core optical fiber and optoelectronic chip array

technical field

The invention belongs to the field of optoelectronic devices for communication. The invention relates to a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array.

Background technique

With the explosive growth of information, the demand for network bandwidth continues to grow rapidly. To obtain greater optical communication capacity, one direction is to use higher-speed devices, such as 100G and 400G optical devices. These high-speed optical devices have a high technical threshold, resulting in long R&D cycles and high production costs. Another direction is to develop space-division multiplexing technology, which uses multi-core optical fibers to transmit optical signals. As shown in Figure 1, the size of multi-core fiber is comparable to that of traditional single-mode fiber, but multiple cores are evenly distributed in the cladding, and these cores can transmit optical signals simultaneously and independently. Therefore, under the same capacity requirements, It can greatly reduce the requirements on device speed, and the technical threshold is relatively low.

The use of this multi-core fiber also brings a new problem, that is, how to conveniently realize the optical coupling between the multi-core fiber and the optoelectronic chip array. Because the cores in the multi-core optical fiber are usually arranged symmetrically to the center, and the optoelectronic chip array is usually arranged in a straight line, the traditional coupling method between the single-mode fiber and the optoelectronic chip is obviously no longer applicable. A suitable mode field converter must be added between the multi-core fiber and the optoelectronic chip array to realize the mutual conversion between the centrosymmetric mode field distribution and the linear mode field distribution.

There are three existing implementation methods, one is to use block optical components to achieve, use lens groups to spread the light in the multi-core optical fiber, and then use optical fiber bundles arranged symmetrically in the center for coupling alignment, and finally in the optical fiber bundle The other end is connected to the device. This kind of device is very complicated to implement, has a large volume and high production cost, and is not suitable for large-scale application.

The other is to use a tapered fiber bundle to achieve, that is, put multiple optical fibers together to heat and tapered, and then cut from the middle, so that one end of the obtained fiber bundle can match the core of the multi-core optical fiber, and the other end is Scattered optical fibers that can be used to interconnect devices. This method also takes up a lot of space, and it is not suitable to be packaged together with the device in a package.

The last solution is to use a three-dimensional waveguide chip to achieve a three-dimensional waveguide directly in the substrate material by using a femtosecond laser, so that one end is symmetrically distributed to match the multi-core optical fiber, and the other end is arranged in a straight line to match the optical fiber array. match. This method of three-dimensional processing of the waveguide is not mature and the cost is very high. In addition, since laser direct writing technology is more suitable for processing straight waveguides, and this method inevitably has an optical path turning, it will bring additional losses.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for realizing optical coupling between multi-core optical fiber and optoelectronic chip array with small occupation volume, low cost and large-scale application.

In order to solve the above-mentioned technical problem, the present invention provides a kind of method that realizes the optical coupling of multi-core optical fiber and optoelectronic chip array, comprising fixing the spacer in the shell, then putting solder into the small groove on the spacer; Put the optoelectronic chip in the corresponding groove, melt the solder to fix the optoelectronic chip, and then complete the electrical connection of the optoelectronic chip by wire bonding; after aligning the end face of the multilayer waveguide with the light emitting surface of the pad, fix the multilayer waveguide ; adjust and fix the position of the lens group, and then align and fix the multi-core optical fiber to realize the optical coupling between the multi-core optical fiber and the optoelectronic chip array.

The manufacturing steps of the multilayer waveguide are as follows:

Step 10, depositing a layer of low refractive index material on the substrate material as a cladding layer, forming two waveguide patterns by photolithography, and then forming the first layer of high refractive index waveguide by diffusion or ion implantation;

Step 11. Deposit a substrate layer on the first waveguide chip formed in step 10, the height of which corresponds to the core distance of the multi-core optical fiber, and then form three waveguide patterns by photolithography, and use the method of diffusion or ion implantation forming a second layer of high refractive index waveguides;

Step 12. Deposit a substrate layer on the second waveguide chip formed in step 11, the height of which corresponds to the core distance of the multi-core optical fiber, and then form two waveguide patterns by photolithography, and use diffusion or ion implantation The method forms the third layer high refractive index waveguide;

Step 13, growing a protective layer, and after cleavage, end face treatment, coating and other processes, a multilayer waveguide is obtained.

The implementation steps of the pad are as follows:

First process platforms with three different heights, the height difference of which corresponds to the core distance of the multi-core optical fiber;

At the corresponding optoelectronic chip installation position, a groove is made by etching, and its size is consistent with the size of the optoelectronic chip;

A small groove is etched in the groove, and finally the required circuit is printed on the platform.

The present invention provides a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array. The core component is a multi-layer waveguide, which is processed by a planar optical waveguide process. Its advantages are as follows:

1. The existing process conditions can be fully utilized. A large number of multilayer waveguide chips can be produced at one time on a wafer, which is suitable for large-scale, low-cost, and high-consistency production.

2. The multilayer waveguide occupies less volume, has a regular shape, and can be conveniently placed in a package, so it is more suitable for packaging with optoelectronic chips of various shapes and purposes.

Description of drawings

1 is a schematic cross-sectional view of a multi-core fiber in a method for realizing optical coupling between a multi-core fiber and an optoelectronic chip array provided by an embodiment of the present invention;

2 is a schematic diagram of optical interconnection between a multi-core fiber and an optoelectronic chip array in a method for realizing optical coupling between a multi-core fiber and an optoelectronic chip array provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of an end face of a multi-layer waveguide coupled with a multi-core fiber in a method for realizing optical coupling between a multi-core fiber and an optoelectronic chip array provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of an end face of a multi-layer waveguide coupled with an optoelectronic chip array in a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array provided by an embodiment of the present invention;

Fig. 5 is a schematic diagram of a spacer equipped with an optoelectronic chip array in a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array provided by an embodiment of the present invention;

6 is a schematic diagram of a V-groove after a cylindrical optoelectronic chip array is installed in a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array provided by an embodiment of the present invention;

7-11 are schematic diagrams of the fabrication process of a multi-layer waveguide in a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array provided by an embodiment of the present invention;

Fig. 12 is an effect diagram after the multi-layer waveguide is fabricated in a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array provided by an embodiment of the present invention;

13 is a schematic cross-sectional view of a spacer in a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array according to an embodiment of the present invention;

Among them, 1—multi-core optical fiber, 2—lens group, 3—multilayer waveguide, 4—block, 5—optoelectronic chip, 6—multilayer waveguide facing the end face of multicore fiber, 7—multilayer waveguide facing the optoelectronic chip array 8—solder, 9—substrate layer, 10-16—waveguide, 17—groove, 18—small groove.

Detailed ways

As shown in Figures 1-13, the present invention provides a method for realizing the optical coupling of a multi-core optical fiber 1 and an array of optoelectronic chips 5. Taking the coupling of a laser array and a seven-core optical fiber as an example, the present invention is described in detail. The specific method for realizing the coupling of the laser array and the seven-core optical fiber includes the following steps:

Step 1. Fix the spacer 4 in the shell, and then put the solder 8 in the small groove 18 on the spacer 4;

Step 2. Put the optoelectronic chip 5 in the corresponding groove 17, melt the solder 8 to fix the optoelectronic chip 5, and then complete the electrical connection of the optoelectronic chip 5 by wire bonding, and a level surface appears on the end surface of the pad 4. The direction is linear, and the vertical direction has a mode field distribution with equidistant height difference;

Step 3. After aligning the end face of the multilayer waveguide 3 with the light exit surface of the spacer 4, fix the multilayer waveguide 3; in this way, a centrosymmetric mode field distribution can appear on the end face of the multilayer waveguide 3;

Step 4. Adjust and fix the position of the lens group 2, and then align and fix the multi-core optical fiber 1 to realize optical coupling between the multi-core optical fiber 1 and the optoelectronic chip 5 array.

Before optical coupling, the required multi-layer waveguide 3 and spacer 4 must be processed according to the size of the multi-core optical fiber 1 .

As shown in Figure 7-11, the multilayer waveguide 3 can be realized by planar waveguide processing technology. The realization of the preparation of the multilayer waveguide 3 includes the following steps:

Step 10, depositing a layer of low refractive index material on the substrate material as a cladding layer, forming two waveguide patterns by photolithography, and then forming a layer of two waveguides 10 and 11 with high refractive index by means of diffusion or ion implantation The waveguide chip;

Step 11, deposit a layer of substrate layer 9 on the layer of waveguide chip formed in step 10, the height of which corresponds to the core distance of the multi-core optical fiber 1, and then use the method of step 10 to make three waveguides 12, 13, 14;

Step 12, on the waveguide chip formed in step 11, deposit a layer of substrate layer 9 with the same height as step 11, and form two waveguides 15, 16 in the same way as step 10 or 11;

Step 13, grow another substrate layer 9 as a protective layer, and undergo processes such as cleavage, section treatment, and coating to obtain a multilayer waveguide 3 . After the multilayer waveguide 3 is processed, its effect is shown in FIG. 12 .

As shown in Figure 13, spacer 4 can be prepared in the following manner:

Step 20, first process platforms with three different heights on the block 4;

Step 30, at the installation position corresponding to the optoelectronic chip 5 on the platform, make a groove 17 by etching, the size of which is consistent with the size of the optoelectronic chip 5, and its height difference must be consistent with the height difference between the multilayer waveguides 3;

Step 40, etching a small groove 18 in the groove 17, and then printing the required circuit on the platform. After the pad 4 is processed, its end face is shown in Figure 13 .

As shown in FIG. 1 , the cores of the multi-core optical fiber 1 are arranged symmetrically to the center, and the typical number of cores is seven, but other numbers are also possible. As shown in FIG. 2 , the function of the lens group 2 is to properly converge and collimate the light field between the multi-core fiber 1 and the multilayer waveguide 3 , so as to increase the coupling tolerance and improve the coupling efficiency. The lens group 2 can be a single lens or a lens group. In some occasions where precise coupling can be performed, the lens group 2 can be omitted, and the end faces of the multi-core optical fiber 1 and the multilayer waveguide 3 are directly aligned. As shown in FIG. 3 , the multilayer waveguide 3 is a waveguide structure with multiple layers and multiple cores, and its function is to realize the mutual conversion between the centrosymmetric mode field distribution and the linear mode field distribution. On one end face 6 of the multi-layer waveguide 3 , the waveguides are center-symmetrically distributed, matching the core distribution of the multi-core optical fiber 1 . As shown in FIG. 4 , the other end surface 7 of the multilayer waveguide 3 is distributed in a straight line in the horizontal direction, and has a certain height difference in the vertical direction. As shown in FIG. 5 , the spacer 4 controls the position and height of the optoelectronic chip 5 to realize the direct connection between the multilayer waveguide 3 and the array of optoelectronic chips 5 . The installation position of the optoelectronic chip 5 corresponds to the position of the waveguide on the other end face 7 of the multilayer waveguide. In order to facilitate placement and fixing of the optoelectronic chip 5 , it is necessary to etch a groove 17 at the mounting position of the optoelectronic chip 5 , and fill the bottom of the groove 17 with solder 8 . In order to facilitate the electrical connection of the 5 rows of optoelectronic chips, a circuit must be processed on the pad 4 as required. When the optoelectronic chip 5 array is cylindrical, the spacer can be processed into a v-groove form, as shown in FIG. 6 . In this embodiment, the optoelectronic chip 5 can be an active chip, a passive chip or an optical fiber for communication, such as a laser chip, a detector chip, an optical fiber, a semiconductor optical amplifier chip, an erbium-doped optical fiber amplifier chip, and the like.

If the optoelectronic chip 5 is a semiconductor optical amplifier, erbium-doped fiber amplifier chip, etc., both ends need to be interconnected with the multi-core optical fiber 1, then a multilayer waveguide 3 and a lens group 2 need to be used at the other end of the optoelectronic chip 5 array. , to achieve optical coupling with another multi-core optical fiber 1 .

The invention provides a method for realizing optical coupling between a multi-core optical fiber and an optoelectronic chip array. The multilayer waveguide, the core component, is processed by a planar optical waveguide process, which can make full use of the existing process conditions. A large number of multilayer waveguide chips can be produced at one time on a wafer, which is suitable for large-scale, low-cost, and high-consistency production. The multilayer waveguide occupies a small volume and has a regular shape, which can be conveniently placed in a package, so it is more suitable for packaging with optoelectronic chips suitable for various shapes and purposes.

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention without limitation, although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (8)

1. a method that realizes multi-core fiber and the optically-coupled of opto chip array is characterized in that, comprising:

Cushion block is fixed in the shell, then puts into scolder in the little groove on cushion block;

Opto chip is placed in the corresponding groove, scolder is melted with the fixed light electronic chip, finish again the electrical connection of opto chip by the routing mode;

With the end face of multilayer waveguide with after the exiting surface of cushion block is aimed at, fixing multilayer waveguide;

Adjust the also position of fixed lens group, then aim at multi-core fiber and fixing, realize multi-core fiber and the optically-coupled of opto chip array.

2. method according to claim 1 is characterized in that, described multilayer waveguide makes by following steps:

By doing maintenance at substrate deposition low-index material, form the waveguide figure by photoetching, then the way formation with diffusion or Implantation has the high index of refraction multilayer waveguide.

3. method according to claim 2 is characterized in that, described multilayer waveguide makes by following steps:

Step 10, do covering at backing material deposition one deck low-index material, form two waveguide figures by photoetching, the method with diffusion or Implantation forms the ground floor high index waveguide again;

Step 11, the ground floor waveguide chip that forms in step 10 deposit one deck substrate layer, its height is corresponding with the fibre core spacing of described multi-core fiber, form three waveguide figures by photoetching again, and form second layer high index waveguide with the method for diffusion or Implantation;

Step 12, the second layer waveguide chip that forms in step 11 deposit one deck substrate layer, its height and the core of described multi-core fiber are apart from corresponding, form two waveguide figures by photoetching again, and form the 3rd floor height refractive index waveguide with the method for diffusion or Implantation;

Step 13, growth layer protective layer, through cleavage, end face processing behind the coating process, obtains multilayer waveguide.

4. method according to claim 1 is characterized in that, the implementation step of described cushion block is as follows:

Process first the platform with three differing heights, its difference in height is corresponding with the fibre core spacing of described multi-core fiber;

In the opto chip installation site of correspondence, make groove with the method for etching, its size and opto chip consistent size;

In groove, etch again a little groove, print required circuit at platform at last.

5. method according to claim 1 is characterized in that: the arrangement that is centrosymmetric of described multi-core fiber fibre core.

6. method according to claim 3 is characterized in that: the distribution that is centrosymmetric of described multilayer waveguide one end, the described multilayer waveguide other end linearly distributes in the horizontal direction, has difference in height at vertical direction.

7. method according to claim 1 is characterized in that, described lens combination is single lens or lens combination.

8. method according to claim 1, it is characterized in that: described opto chip is active chip, passive chip or optical fiber.

Images