阅读说明：本技术 一种凸型多模光波导及多模色散调控方法 (Convex multimode optical waveguide and multimode dispersion regulation and control method ) 是由 程振洲 陈威成 岳龚成 胡浩丰 刘铁根 于 2020-06-30 设计创作，主要内容包括：本发明公开一种凸型多模光波导及多模色散调控方法,多模光波导包括光波导层、绝缘层、衬底层；绝缘层位于衬底层之上,光波导位于绝缘层之上。凸型多模光波导的形貌可以是一个凸形结构,也可以是多个凸形结构的组合。凸型多模光波导的色散控制方法可以控制凸型多模光波导中多个空间模式的色散,首先,设计光波导层的一组结构尺寸参数,包括宽度W,横向刻蚀宽度W1,垂直刻蚀深度H,根据不同空间模式在所述新型的凸型多模光波导的有效折射率的二阶导数计算得到不同空间模式的色散曲线；然后,通过调整宽度W、横向刻蚀宽度W1、垂直刻蚀深度H中的一个参数或多个参数,从而实现多个空间模式的色散控制。(The invention discloses a convex multimode optical waveguide and a multimode dispersion regulation and control method, wherein the multimode optical waveguide comprises an optical waveguide layer, an insulating layer and a substrate layer; the insulating layer is located on the substrate layer, and the optical waveguide is located on the insulating layer. The convex multimode optical waveguide can be in a convex structure or a combination of a plurality of convex structures. Firstly, designing a group of structural size parameters of an optical waveguide layer, including width W, transverse etching width W1 and vertical etching depth H, and calculating to obtain dispersion curves of different spatial modes according to second-order derivatives of effective refractive indexes of different spatial modes in the novel convex multimode optical waveguide; then, by adjusting one or more of the width W, the lateral etching width W1 and the vertical etching depth H, dispersion control of a plurality of spatial modes is realized.)

1. A convex multimode optical waveguide is characterized by comprising an optical waveguide layer, an insulating layer and a substrate layer which are arranged from top to bottom in sequence; the whole multimode optical waveguide is of a convex structure or is formed by combining a plurality of convex structures, and the working ranges are visible light wave bands, communication light wave bands, middle infrared wave bands and far infrared wave bands.

2. The male multimode optical waveguide of claim 1 wherein said optical waveguide layer material is comprised of one of silicon, germanium, a silicon-germanium mixture, silicon nitride, indium phosphide, gallium arsenide, lithium niobate.

3. The male multimode optical waveguide of claim 1 wherein the male multimode waveguide supports a number of spatial modes and the spatial modes are transverse electric or magnetic modes.

4. The method for manufacturing the convex multimode optical waveguide is characterized in that the convex multimode optical waveguide is manufactured and finished by laser direct writing, electron beam exposure combined etching, photoetching combined etching or focused ion beams.

5. A dispersion regulation and control method of a convex multimode optical waveguide is characterized in that dispersion control is respectively realized aiming at each space mode in the convex multimode optical waveguide by controlling the number, distribution and geometric dimension of convex structures of the convex multimode optical waveguide.

Technical Field

The invention belongs to the field of integrated photoelectron, and particularly relates to a novel optical waveguide and a multimode dispersion regulation and control method.

Background

The mode division multiplexing silicon-based integrated optical circuit technology has great application potential in expanding the bandwidth of optical communication and optical interconnection and the like. As with other multiplexing techniques (e.g., time division multiplexing, wavelength division multiplexing, polarization division multiplexing, etc.), multiple orthogonal spatial modes in a multimode optical waveguide are used as channels, providing an additional degree of freedom for expanding the information capacity of an optical communications network. By fully utilizing the characteristics of the technology, the data transmission speed of 10.68Tbit/s in the field of high-speed optical interconnection is proved. In addition, the mode division multiplexing silicon-based photonic integrated circuit is widely applied to the fields of on-chip optical receivers, optical switches, optical routes and the like.

On the other hand, the silicon material has the wavelength of 2.6 × 10^ 10 at 1550nm^-18m²The Kerr nonlinear refractive index of/W and the silicon-based photonic integrated circuit are widely concerned in the nonlinear optical fields of optical parametric devices, nonlinear optical signal processing and the like. Controlling the group velocity dispersion of the material is an indispensable technique for achieving high efficiency and high bandwidth optical parametric applications in silicon waveguides. Previous studies have shown that by adjusting the structural characteristics of silicon waveguides and their corresponding parameters, a flat anomalous dispersion curve can be obtained over a very short spectral range, thereby achieving the same operation at multiple wavelengths. Therefore, in a single mode, technologies such as on-chip optical frequency combing, supercontinuum, signal parametric amplification and regeneration, and the like have been widely studied. However, group velocity dispersion has a strong dependence on spatial modes within the waveguide, and dispersion curves of different spatial modes are different in a plurality of spatial modes, so that corresponding mode-division multiplexing optical parametric devices and applications still have certain challenges. It is expected that multimode waveguides with flat and anomalous group velocity distributions for multiple spatial modes will help achieve mode multiplexing optical parametric devices, as well as mode division multiplexing and wavelength division diverse multidimensional signal processing.

Researchers have conducted extensive research directed to single mode dispersion regulation. In the thesis, Michal Lipson et al, cornell university, usa, achieved dispersion modulation on a strip silicon waveguide in 2006 (OpticsExpress,14,10, 4357). By adjusting the cross-sectional area and shape of the waveguide, the group velocity dispersion can be tuned in the range of-2000 ps/nm/km to 1000 ps/nm/km. Govind p. agrawal et al, university of rochester, 2006 studied dispersion control for silicon-on-insulator waveguides using an effective refractive index approach, and the dispersion of silicon waveguides at 1550nm could be tuned to zero dispersion by tuning the waveguide dimensions (Optics Letters,31,9, 1295). Dispersion management for single mode slot waveguides was studied by Javier marti, et al, of the university of valencia, spain 2010 (Optics Express,18,20, 20839). Researches find that the zero dispersion wavelength and the peak dispersion can be obtained by regulating and controlling parameters such as the cross-sectional area of the waveguide, the gap filling factor, the gap asymmetry and the like. However, the above studies are all the regulation of dispersion of a single mode (fundamental mode of the waveguide) in the waveguide, and the regulation of dispersion of a plurality of spatial modes (fundamental mode and higher-order mode of the waveguide) is not realized.

In the patent, zhanglin et al, the university of tianjin in 2016, applied for the chinese patent invention (201610149999.5) by adjusting one or more parameters of the width of the waveguide core region and the substrate contact surface, the height of the high refractive index material, and the height of the low refractive index material, thereby achieving dispersion control. Chengminghua et al, the university of Qinghua in 2017, applied for a Chinese patent of invention (201710525571.0), which can control the dispersion value by adjusting the width interval between waveguide cores, using the mode coupling principle. However, in the above patents of waveguide dispersion modulation, control of multiple spatial mode dispersions is also not achieved.

In summary, although the dispersion control in the waveguide has been widely studied, the dispersion control of multiple spatial modes in the waveguide is still difficult to be realized due to the dependence of dispersion on the spatial modes, which limits the development and application of the mode division multiplexing optical parametric device to a certain extent.

Disclosure of Invention

The invention aims to solve the problem that the dispersion curves of different spatial modes are different in the prior art, so that the limitations of the mode division multiplexing optical parametric device and the application are caused. A convex multimode optical waveguide and a multimode dispersion control method are provided.

The purpose of the invention is realized by the following technical schemes:

a convex multimode optical waveguide comprises an optical waveguide layer, an insulating layer and a substrate layer which are arranged from top to bottom in sequence; the whole multimode optical waveguide is of a convex structure or is formed by combining a plurality of convex structures, and the working ranges are visible light wave bands, communication light wave bands, middle infrared wave bands and far infrared wave bands.

Furthermore, the optical waveguide layer material is composed of one of silicon, germanium, silicon-germanium mixture, silicon nitride, indium phosphide, gallium arsenide and lithium niobate.

Further, the convex multimode waveguide supports a plurality of spatial modes, and the spatial modes are transverse electric modes or transverse magnetic modes.

A method for making convex multi-mode optical waveguide is carried out by laser direct writing, electron beam exposure combined etching, photoetching combined etching or focusing ion beam making.

A dispersion regulation and control method of a convex multimode optical waveguide is characterized in that dispersion control is respectively realized aiming at each space mode in the convex multimode optical waveguide by controlling the number, distribution and geometric dimension of convex structures of the convex multimode optical waveguide.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

(1) the dispersion control method can simultaneously and respectively realize normal dispersion or anomalous dispersion on a plurality of space modes in the waveguide, is beneficial to realizing high-efficiency nonlinear optical frequency conversion on the plurality of space modes in the same waveguide, and can be used for developing on-chip integrated multimode nonlinear optical lasers.

(2) The manufacturing process of the device is completely compatible with the existing CMOS process, and is beneficial to realizing large-scale mass production of the device.

(3) The invention opens up a new way for researching the on-chip integrated mode division multiplexing nonlinear optical signal processing technology and application. The novel optical waveguide can realize flexible dispersion cutting aiming at different space modes, thereby balancing the conversion efficiency of nonlinear effects such as four-wave mixing and the like in different space modes, promoting the development of an on-chip integrated mode division multiplexing nonlinear optical signal processing technology, and having wide application prospect in the fields of optical communication, optical interconnection and the like.

Drawings

Fig. 1 is a schematic structural diagram of the novel convex multimode optical waveguide of the present invention.

Fig. 2 is a material dispersion curve for silicon.

FIG. 3 shows TE at 70nm for a waveguide width of 0.8 μm, a lateral etching width of 0.5 μm₀And TE₁The dispersion curve of (1).

FIG. 4 shows TE at 150nm, with a waveguide width of 1 μm, a lateral etching width of 0.4 μm₀And TE₁The dispersion curve of (1).

Detailed Description

The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.