阅读说明：本技术 一种应用于中红外波段的悬空型边缘耦合器 (Suspended edge coupler applied to intermediate infrared band ) 是由 王书晓 王庆 蔡艳 余明斌 王曦 于 2020-06-02 设计创作，主要内容包括：本发明涉及一种应用于中红外波段的悬空型边缘耦合器,包括三端口倒锥形耦合器(1)、悬空脊型波导(2)和悬梁臂支撑结构(3)。本发明通过独特的结构设计增大了耦合效率,同时增大了工艺容差,也为测试带来了极大的方便,解决了中红外波段波导-光纤耦合损耗大的问题,具有良好的应用前景。(The invention relates to a suspended edge coupler applied to a mid-infrared band, which comprises a three-port inverted cone coupler (1), a suspended ridge waveguide (2) and a cantilever arm supporting structure (3). The invention increases the coupling efficiency through the unique structural design, increases the process tolerance, brings great convenience to the test, solves the problem of large coupling loss of the intermediate infrared waveband waveguide and the optical fiber, and has good application prospect.)

1. The utility model provides a be applied to unsettled type edge coupler of mid-infrared band which characterized in that: the three-port inverted cone coupler comprises a three-port inverted cone coupler (1), a suspended ridge waveguide (2) and a cantilever arm supporting structure (3); the three-port inverted cone coupler (1) is directly connected with the suspended ridge waveguide (2); the cantilever beam arm supporting structure (3) is used for supporting the three-port inverted cone coupler (1).

2. The suspended edge coupler of claim 1, wherein: and the port in the three-port inverted cone coupler (1) is used for receiving the light input of the intermediate infrared band.

3. The suspended edge coupler of claim 1, wherein: the cantilever arm supporting structure (3) is composed of a plurality of parallel strip waveguides.

4. The suspended edge coupler of claim 3, wherein: the thickness of the strip waveguide is the same as that of the three-port inverted cone coupler (1) or the thickness of the slab region of the suspended ridge waveguide (2).

Technical Field

The invention belongs to the field of couplers, and particularly relates to a suspended edge coupler applied to a mid-infrared band.

Background

The SOI material is an important optical waveguide material applied to silicon-based photonics, can be compatible with a mature CMOS process, and has low production cost and high process stability. The mid-infrared band (2-20 μm) is an important band range in the spectrum, and the absorption peaks of many gases are concentrated in the band, so that the sensor has important application in sensing. The absorption loss of silicon materials is low at 3-8um, but the absorption loss of substrate silicon dioxide is high after the wavelength of >3.5 um, so that if the transmission loss of silicon-based waveguides prepared by using traditional SOI materials is large, the same problem is faced by the traditional couplers. For the problem of large waveguide transmission loss, a silicon dioxide substrate is generally hollowed out, that is, a suspended ridge waveguide is adopted to reduce the transmission loss. However, the coupling efficiency of the waveguide-fiber coupling directly performed by the pure ridge waveguide is very low, so that it is necessary to design a suspended coupler capable of reducing the coupling loss.

CN108020889A discloses an optical waveguide coupler, which is composed of multiple waveguides with gradually changed widths and heights. The technical scheme is not suitable for the intermediate infrared band and cannot solve the problem of high substrate loss of the intermediate infrared band.

Disclosure of Invention

The invention aims to solve the technical problem of providing a suspended edge coupler applied to a middle infrared band, and solving the problem of large coupling loss of waveguide-optical fiber in the middle infrared band.

The invention provides a suspended edge coupler applied to a mid-infrared band, which comprises a three-port inverted cone coupler, a suspended ridge waveguide and a cantilever arm supporting structure, wherein the three-port inverted cone coupler is connected with the suspended ridge waveguide; the three-port inverted cone coupler is directly connected with the suspended ridge waveguide; the cantilever arm support structure is used for supporting the three-port inverted cone coupler.

And the ports in the three-port inverted cone coupler are used for receiving light input of a middle infrared band.

The cantilever beam arm support structure is composed of a plurality of parallel strip waveguides.

The thickness of the strip waveguide is the same as that of the three-port inverted cone coupler or the thickness of the slab region of the suspended ridge waveguide.

The coupling part of the invention adopts the suspended strip waveguide, and the inverted cone coupler with three ports can increase the area of a mode field in the waveguide, thereby increasing the coupling efficiency with a light field in an optical fiber, and simultaneously, the suspended structure also solves the problem of high absorption loss of a substrate. And the transmission loss of the coupler is reduced by adopting a tapered waveguide structure to transition to a ridge waveguide. For the design of the cantilever beam arm supporting structure, the cantilever beam arm which meets the sub-wavelength grating structure can be designed, and the influence on the optical field transmission in the coupler is avoided. Therefore, the structure can realize low-loss fiber-waveguide coupling of the mid-infrared band, and has profound significance for application of mid-infrared band silicon optical devices.

Advantageous effects

The invention adopts the cantilever beam arm waveguide to support the suspended strip waveguide coupler, and the cantilever beam arm needs to meet the condition of stably supporting the coupler and reduce the influence on the optical field in the coupler as much as possible; according to the invention, the coupling area of the optical field in the waveguide and the optical field in the optical fiber is increased by constructing the suspended three-port inverted cone coupler, so that the coupling efficiency is increased; meanwhile, the structure is simple in preparation process, can increase process tolerance, brings great convenience to testing, solves the problem of large coupling loss of the intermediate infrared band waveguide and the optical fiber, and has good application prospect.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a flow chart of the preparation of the present invention.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.