WO2016090534A1

WO2016090534A1 - Waveguide device and chip comprising same

Info

Publication number: WO2016090534A1
Application number: PCT/CN2014/093294
Authority: WO
Inventors: 刘万元
Original assignee: 华为技术有限公司
Priority date: 2014-12-08
Filing date: 2014-12-08
Publication date: 2016-06-16
Also published as: CN106687836A

Abstract

A waveguide device and a chip comprising same. The waveguide device comprises a first waveguide structure (150, 250, 350) and a second waveguide structure (160, 260, 360) which are coupled. The first waveguide structure (150, 250, 350) is constituted by a first straight waveguide (110, 210, 310), a first bent waveguide (101, 201, 301) and a second straight waveguide (120, 220, 320), and the first straight waveguide (110, 210, 310) and the second straight waveguide (120, 220, 320) are connected via the first bent waveguide (101, 201, 301). The second waveguide structure (160, 260, 360) is constituted by a third straight waveguide (130, 230, 330), a second bent waveguide (102, 202, 302) and a fourth straight waveguide (140, 240, 340), and the third straight waveguide (130, 230, 330) and the fourth straight waveguide (140, 240, 340) are connected via the second bent waveguide (102, 202, 302). The waveguide device avoids the mutation of the spatial structure of the device resulting from the direct crossing of the waveguides, thus reducing the transmission loss effectively when the light beam is transmitting.

Description

Waveguide

Technical field

Embodiments of the present invention relate to the field of optics and, in particular, to a waveguide device.

Background technique

Since the advent of the first laser, human communication has undergone profound changes. As a carrier of information, light makes people's communication timely and convenient with its high speed and stable characteristics. With the development of technology, traditional module optics gradually show its shortcomings in power consumption and duty cycle. Optical path design has tried to integrate in a variety of materials, but limited by the process and limited development. While silicon light has received much attention due to its compatibility with circuit processes, it is expected that integrated optical energy will travel the same way as electricity on silicon.

The high refractive index contrast of silicon light makes it suitable for large-scale and high-density integration. At the same time, it can also utilize the mature complementary metal oxide semiconductor process of the electric chip, which makes silicon light unique. However, the optical path does not have the flexibility of the circuit. In large-scale switching matrices, the intersection of waveguides is unavoidable. In a silicon light platform, the cross-waveguide is an extremely core device. If the loss value of a cross-waveguide is 0.3 dB, if the number of cross-waveguides is 100 in one switch matrix, the loss caused by only the cross-waveguide reaches 30 dB, which is a very serious loss. Therefore, it is necessary to reduce the loss of the cross-waveguide.

In many cross-waveguide designs, the direct crossover structure of the waveguide is adopted. Due to the direct straddle of the waveguide, the abrupt change of the spatial structure of the device causes the divergence of the beam, and still generates a large cross-wave loss.

Summary of the invention

Embodiments of the present invention provide a waveguide device capable of effectively reducing transmission loss in a waveguide.

In a first aspect, a waveguide device is provided, comprising: a first waveguide structure composed of a first straight waveguide, a first curved waveguide, and a second straight waveguide, the first straight waveguide and the second straight waveguide passing through The first curved waveguide is connected; the second waveguide structure is composed of a third straight waveguide, a second curved waveguide, and a fourth straight waveguide, and the third straight waveguide and the fourth straight waveguide pass through the second curved waveguide Connected; wherein the first waveguide structure and the second waveguide structure are coupled.

In conjunction with the first aspect, in a first possible implementation manner of the first aspect, the second straight waveguide and the fourth straight waveguide are parallel in a first direction, the second straight waveguide and the fourth The distance between the straight waveguides in the second direction is greater than zero and less than the wavelength of the light beam transmitted at the waveguide device, the first direction being perpendicular to the second direction, the first waveguide structure and the first The coupling portion between the two waveguide structures has an odd multiple of the coupling length.

In conjunction with the first possible implementation of the first aspect, in a second possible implementation of the first aspect, the length of the coupling portion between the first waveguide structure and the second waveguide structure is a coupling length .

With reference to the first aspect, the first or second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, the first straight waveguide, the second straight waveguide, the third straight waveguide, The fourth straight waveguide, the first curved waveguide, and the second curved waveguide are all single mode waveguides.

With reference to the first aspect, any one of the first to third possible implementations of the first aspect, in a fourth possible implementation of the first aspect, the first light beam input from the first straight waveguide Output from the third straight waveguide.

With reference to the first aspect, any one of the first to third possible implementations of the first aspect, in a fifth possible implementation of the first aspect, the second light beam input from the second straight waveguide Output from the fourth straight waveguide.

With reference to the first aspect, any one of the first to third possible implementations of the first aspect, in a sixth possible implementation of the first aspect, the third light beam input from the third straight waveguide Output from the second straight waveguide.

In conjunction with the first aspect, any one of the first to third possible implementations of the first aspect, in a seventh possible implementation of the first aspect, the fourth beam input from the fourth straight waveguide Output from the first straight waveguide.

With reference to the first aspect, any one of the first to seventh possible implementations of the first aspect, in the eighth possible implementation of the first aspect, the first straight waveguide and the second straight waveguide are mutually Vertically, the third straight waveguide and the fourth straight waveguide are perpendicular to each other.

In a second aspect, a chip is provided, comprising the waveguide device provided by the first aspect.

Since the waveguide device of the embodiment of the present invention adopts a structure based on the waveguide coupling principle, the direct straddle of the waveguide is avoided to cause a sudden change in the spatial structure of the device, so that the transmission loss is effectively reduced at the time of transmission.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

1 is a schematic structural view of a waveguide device in accordance with an embodiment of the present invention.

2 is a structural schematic view of a waveguide device in accordance with another embodiment of the present invention.

2A is a structural schematic view of a waveguide device in accordance with another embodiment of the present invention.

3 is a structural schematic view of a waveguide device in accordance with still another embodiment of the present invention.

4 is a schematic diagram showing the power distribution of a transmission beam according to still another embodiment of the present invention.

FIG. 5 is a schematic diagram showing a power distribution of a transmission beam according to still another embodiment of the present invention.

Figure 6 is a schematic illustration of the relationship between exit end loss and beam wavelength in accordance with yet another embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are an embodiment of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

1 is a schematic structural view of a waveguide device in accordance with an embodiment of the present invention. The waveguide device 100 of FIG. 1 includes a first waveguide structure 150 composed of a first straight waveguide 110, a first curved waveguide 101, and a second straight waveguide 120, the first straight waveguide 110 and the second straight waveguide 120 passing through the first curved waveguide 101 phase connection;

The second waveguide structure 160 is composed of a third straight waveguide 130, a second curved waveguide 102, and a fourth straight waveguide 140, and the third straight waveguide 130 and the fourth straight waveguide 140 are connected by the second curved waveguide 102; The waveguide structure 150 and the second waveguide structure 160 are coupled.

It should be understood that for the waveguide device, the first straight waveguide and the second straight waveguide may be perpendicular to each other or may be other angles; similarly, the third straight waveguide and the fourth straight waveguide may be perpendicular to each other or may be at other angles. The straight waveguide and the curved waveguide appearing herein may be single mode waveguides or multimode waveguides. Preferably, all of the waveguides are single mode waveguides. The waveguide in the text can be made of any waveguide material, for example, the core layer is made of silicon and the cladding layer is made of silicon dioxide. High refractive index contrast of silicon light It can be applied to large-scale high-density integration; at the same time, it can also utilize the mature complementary metal oxide semiconductor process of the electric chip, which makes silicon light unique.

It should also be understood that the first waveguide structure and the second waveguide structure are coupled, and the waveguide device may have different functions based on the length of the coupling portion. For example, the function of the cross-waveguide can be achieved when the beam is ultimately coupled to the second waveguide structure for output, or when the second waveguide structure is ultimately coupled to the first waveguide structure for output. For a particular length of some coupling portions, when the beam is coupled between the two waveguide structures, it is still coupled back to the input waveguide structure, for example, from the first waveguide structure input, still output from the first waveguide structure; The second waveguide structure input is still output from the second waveguide structure, where the waveguide can be used to change the direction of the light.

Since the waveguide device of the embodiment of the present invention adopts a structure based on the waveguide coupling principle, the direct straddle of the waveguide avoids abrupt changes in the spatial structure of the device, and thus the transmission loss is effectively reduced when the beam is transmitted.

2 is a structural schematic view of a waveguide device in accordance with another embodiment of the present invention. The waveguide device 200 of FIG. 2 includes a first waveguide structure 250 composed of a first straight waveguide 210, a first curved waveguide 201, and a second straight waveguide 220, and the first straight waveguide 210 and the second straight waveguide 220 pass through the first curved waveguide 201 connected;

The second waveguide structure 260 is composed of a third straight waveguide 230, a second curved waveguide 202, and a fourth straight waveguide 240. The third straight waveguide 230 and the fourth straight waveguide 240 are connected by the second curved waveguide 202; The waveguide structure 250 is coupled to the second waveguide structure 260,

In this embodiment, the second straight waveguide 220 and the fourth straight waveguide 240 are parallel in the first direction, and the distance between the second straight waveguide 220 and the fourth straight waveguide 240 in the second direction is greater than zero and less than The wavelength of the light beam transmitted by the waveguide device is perpendicular to the first direction and the second direction, and the coupling portion between the first waveguide structure 250 and the second waveguide structure 260 has an odd multiple of the coupling length.

Since the waveguide device of the embodiment of the present invention adopts a structure based on the waveguide coupling principle, the direct straddle of the waveguide avoids abrupt changes in the spatial structure of the device, and thus the transmission loss is effectively reduced when the beam is transmitted as a cross-waveguide.

In other words, the waveguide device of the embodiment of the present invention utilizes the principle of mode coupling to form a parallel structure of the waveguide in the intersection region instead of directly straddle, thereby avoiding abrupt changes in the spatial structure of the waveguide, suppressing the divergence of the beam, and making it more Low transmission loss. In addition, the waveguide device of the embodiment of the present invention has a simple structure and is easy to manufacture. In addition, since the coupling portion has an odd multiple coupling length, the light beam input from the A terminal in Fig. 2 can be output from the C terminal, and the light beam input from the B terminal can be from the D terminal. Output.

It should be understood that the coupling length is defined as L=π/2K, where K is the coupling coefficient between the first waveguide structure and the second waveguide structure, the coupling length and the wavelength, and the second between the second straight waveguide and the fourth straight waveguide. The distance in the two directions is related. In other words, the coupling length is the distance between the start of the coupling of the light beam from a certain waveguide structure (ie, the position at which the light intensity begins to decrease) to the position at which the light beam first becomes zero in the waveguide structure, or The distance between where a waveguide beam begins to appear at the coupled beam (ie, where the intensity of the light appears) to where the intensity first reaches its maximum, for example, L1 in Figure 2A corresponding to the embodiment of Figure 2 is the coupling length. . It should be understood that a better coupling effect can be obtained when the distance between the second straight waveguide and the fourth straight waveguide in the second direction is greater than zero and less than the wavelength of the beam transmitted by the waveguide.

It should also be understood that the coupling portion refers to the portion of the beam between a coupling coupling and an ending coupling within a waveguide structure. In other words, the length of the coupling portion is the distance between the position at which the light intensity changes from the start of the coupling to the position at which the light intensity at the end of the coupling is constant. Generally, it mainly depends on the distance between the second straight waveguide and the second straight waveguide in the first direction, that is, mainly depends on the connection between the first curved waveguide and the second straight waveguide in the fourth straight waveguide and the second bending The distance between the waveguides in the first direction. Thus, for the embodiment of Figures 2 and 2A, the distance can be approximately considered to be the length of the coupling portion.

In the case where most of the beam is coupled from one waveguide structure to another, a better function of the cross-waveguide can be achieved.

L2 in Fig. 2A is the length of the coupling portion, and the width of the light beam indicates the light intensity. In the figure, the length of the coupling portion is three times the length of the coupling, and the light beam couples the light beam into the second waveguide structure through the coupling portion in the first waveguide structure. In fact, since most of the light beam is in the straight waveguide Inter-coupled, so that when the coupling portion between the first waveguide structure and the second waveguide structure has an odd multiple of the coupling length, the loss of the transmission belt can be minimized. Preferably, the length of the coupling portion is one time the coupling length.

Still taking FIG. 2A as an example, the coupling portion in the figure has a coupling length of three times. From the intensity of the light indicated by the width of the beam, it is known that the beam is coupled from the second straight waveguide to the fourth straight waveguide at a one-time coupling length in the coupling portion, and from the fourth straight waveguide to the second straight waveguide at the double coupling length And coupling from the second straight waveguide to the fourth straight waveguide at the triple coupling length. In fact, as long as the length of the coupling portion is equal to an odd multiple of the coupling length between the second straight waveguide and the fourth straight waveguide, the function of the ideal cross-waveguide can be achieved with very little energy loss. Even when the length and coupling of the coupling part When there is a tolerance within the engineering margin between the odd multiples of the length, the function of the cross-waveguide can still be well realized.

It should be understood that as a preferred embodiment, the second straight waveguide is adjacent to the fourth straight waveguide to maximize the coupling effect while reducing the size of the waveguide. In addition, as a preferred embodiment, the distance between the first connection and the second connection in the first direction is equal to the coupling length between the second straight waveguide and the fourth straight waveguide, so that the loss of energy can be minimized. At the same time, the size of the cross waveguide can be reduced.

It should also be understood that the coupling length between the second input straight waveguide and the second input straight waveguide is used to generate coupling. As a preferred embodiment, the transmission beam may be passed from the second straight waveguide into the fourth straight waveguide, or From the fourth straight waveguide to the second straight waveguide, in other words, when the odd-numbered coupling length is double the coupling length, it is possible to manufacture a smaller coupling length to reduce the size of the waveguide device. It is also possible that the light beam in the second straight waveguide is alternately transmitted between the two parallel waveguides multiple times, eventually entering the fourth waveguide, or vice versa.

3 is a structural schematic view of a waveguide device in accordance with still another embodiment of the present invention. The waveguide device 300 of FIG. 3 includes a first waveguide structure 350 composed of a first straight waveguide 310, a first curved waveguide 301, and a second straight waveguide 320, and the first straight waveguide 310 and the second straight waveguide 320 pass through the first curved waveguide 301 connected;

The second waveguide structure 360 is composed of a third straight waveguide 330, a second curved waveguide 302, and a fourth straight waveguide 340, and the third straight waveguide 330 and the fourth straight waveguide 340 are connected by the second curved waveguide 302;

Wherein, the first waveguide structure 350 and the second waveguide structure 360 are coupled, the second straight waveguide 320 and the fourth straight waveguide 340 are parallel in the first direction, and the second straight waveguide 320 and the fourth straight waveguide 340 are in the second The distance in the direction is greater than zero and less than the wavelength of the beam transmitted at the waveguide, the first direction being perpendicular to the second direction. The coupling portion between the first waveguide structure 350 and the second waveguide structure 360 has an odd multiple of the coupling length.

In this embodiment, the first straight waveguide and the second straight waveguide are perpendicular to each other, and the third straight waveguide and the fourth straight waveguide are perpendicular to each other.

It should be understood that, in the waveguide device of the present embodiment, the first straight waveguide and the second straight waveguide are perpendicular to each other, and the third straight waveguide and the fourth straight waveguide are perpendicular to each other. Therefore, the problem of the intersection between the transmitted beams when used as a cross-waveguide can be solved to the utmost.

It should also be understood that similar to the embodiment of Figure 1, the waveguide can be of any waveguide material, such as a core. The layer is made of silicon and the cladding is made of silicon dioxide. Similar to the embodiment of Fig. 2, as a preferred embodiment, the second straight waveguide is adjacent to the fourth straight waveguide to maximize the coupling effect while reducing the size of the waveguide. The coupling length between the second input straight waveguide and the second input straight waveguide is used to generate coupling. As a preferred embodiment, the transmission beam may be from the second straight waveguide into the fourth straight waveguide, or from the fourth straight The waveguide is routed into the second straight waveguide such that a smaller coupling length can be made to reduce the size of the waveguide. It is also possible that the light beam in the second straight waveguide is alternately transmitted between the two parallel waveguides multiple times, eventually entering the fourth waveguide, or vice versa.

Since the waveguide device of the embodiment of the present invention employs a structure based on the waveguide coupling principle, the direct straddle of the waveguide avoids abrupt changes in the spatial structure of the device, and thus the transmission loss is effectively reduced when transmitted as a cross-waveguide.

According to an embodiment of the invention, the first light beam input from the first straight waveguide may be output from the third straight waveguide. The second beam input from the second straight waveguide may be output from the fourth straight waveguide. The third beam input from the third straight waveguide may be output from the second straight waveguide. The fourth beam input from the fourth straight waveguide may be output from the first straight waveguide.

Specifically, FIG. 4 is a schematic diagram of the power distribution of the transmitted beam in the embodiment according to FIG. 3. With respect to the waveguide in Fig. 3, Fig. 4 shows the power transmission distribution state of light when light is input from the left end to the first straight waveguide. When light is input from the left end, the light transmitted in the horizontal direction passes through the ninety-degree curved waveguide, the propagation direction is deflected, and the second straight waveguide is coupled with the straight waveguide of the fourth waveguide, and the optical power is fully coupled at this time. After entering the fourth waveguide, the light is again transmitted in the horizontal direction after passing through the third straight waveguide.

Figure 5 is a schematic illustration of the power distribution of another transmitted beam in accordance with the embodiment of Figure 3. With respect to the waveguide of Fig. 3, Fig. 5 shows the power transmission distribution state of light when the second straight waveguide is input from the upper end of the device. When light is input from the upper end, the light is transmitted in the vertical direction at the second straight waveguide to be mode-coupled with the fourth straight waveguide, at which time the optical power is fully coupled into the fourth straight waveguide and continues to be transmitted.

Figure 6 is a schematic illustration of the relationship between exit end loss and beam wavelength in accordance with yet another embodiment of the present invention. As can be seen from Figure 6, at an optimum wavelength of 1.55 um, the device loss is about 0.0036 dB, which is about an order of magnitude lower than the loss of the prior art cross-waveguide. The coupled mode theory is wavelength dependent, and both the coupling length and the coupling efficiency vary with wavelength. As can be seen from the figure, when the wavelength changes by about 4 nm, the exit end loss is about 0.006 dB. Although the loss of the device is wavelength dependent, its loss is still lower than the current technology at a wavelength change of 4 nanometers. The ultra-low loss structure of this patent can be applied to Dense Wavelength Division Multiplexing (DWDM) systems.

The above is only a preferred embodiment of the technical solution of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A waveguide device, comprising: a first waveguide structure composed of a first straight waveguide, a first curved waveguide, and a second straight waveguide, wherein the first straight waveguide and the second straight waveguide pass the first a curved waveguide connected;

a second waveguide structure, which is composed of a third straight waveguide, a second curved waveguide, and a fourth straight waveguide, wherein the third straight waveguide and the fourth straight waveguide are connected by the second curved waveguide;

Wherein the first waveguide structure and the second waveguide structure are coupled.
The apparatus according to claim 1, wherein said second straight waveguide is parallel to said fourth straight waveguide in a first direction, and wherein said second straight waveguide and said fourth straight waveguide The distance in the second direction is greater than zero and less than the wavelength of the beam transmitted at the waveguide device, the first direction being perpendicular to the second direction, between the first waveguide structure and the second waveguide structure The coupling portion has an odd multiple of the coupling length.
The apparatus according to claim 2, wherein a length of the coupling portion between the first waveguide structure and the second waveguide structure is a coupling length.
The apparatus according to any one of claims 1 to 3, wherein the first straight waveguide, the second straight waveguide, the third straight waveguide, the fourth straight waveguide, the The first curved waveguide and the second curved waveguide are both single mode waveguides.
The apparatus according to any one of claims 1 to 4, wherein the first light beam input from the first straight waveguide is output from the third straight waveguide.
The apparatus according to any one of claims 1 to 4, wherein the second light beam input from the second straight waveguide is output from the fourth straight waveguide.
The apparatus according to any one of claims 1 to 4, characterized in that the third light beam input from the third straight waveguide is output from the second straight waveguide.
The apparatus according to any one of claims 1 to 4, characterized in that the fourth light beam input from the fourth straight waveguide is output from the first straight waveguide.
The apparatus according to any one of claims 1-8, wherein the first straight waveguide and the second straight waveguide are perpendicular to each other, and the third straight waveguide and the fourth straight waveguide are mutually vertical.
A chip characterized by comprising the waveguide device according to claims 1-9.