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CN-122018082-A - Optical power distributor based on sub-wavelength grating reinforced conical ultrathin waveguide and preparation method thereof

CN122018082ACN 122018082 ACN122018082 ACN 122018082ACN-122018082-A

Abstract

The invention discloses an optical power distributor based on a sub-wavelength grating reinforced conical ultrathin waveguide and a preparation method thereof, and relates to the technical field of optical communication devices. The optical power distributor is silicon on insulator with a top silicon layer thickness of 70 nm and a preset pattern, the top silicon layer with the preset pattern comprises an input straight waveguide, a first coupling area, a second coupling area and an output waveguide which are sequentially connected, the first coupling area comprises the input tapered waveguide, the first output tapered waveguide and the second output tapered waveguide which are distributed in a staggered mode and is filled with a first sub-wavelength grating, and the second coupling area comprises the first output straight waveguide and the second sub-wavelength grating which are arranged in parallel and are distributed between the two straight waveguides. The optical power splitter can have any split ratio, with large manufacturing tolerances, small relative wavelength deviations, and a wide bandwidth. The 50:50 optical power divider achieves insertion loss <0.38 dB in a wavelength range of 1400-1700 nm.

Inventors

  • ZHENG HUAN
  • WANG JIAQI

Assignees

  • 珠海市亿鸿通信工程有限公司

Dates

Publication Date
20260512
Application Date
20260319

Claims (10)

  1. 1. The optical power distributor based on the sub-wavelength grating enhanced conical ultrathin waveguide is characterized in that the optical power distributor is silicon on insulator with a top silicon layer with a preset pattern, the thickness of the top silicon layer is 70 nm, and the top silicon layer with the preset pattern comprises an input straight waveguide, a first coupling region, a second coupling region and an output waveguide which are sequentially connected along the optical transmission direction; The first coupling region comprises input tapered waveguides, first output tapered waveguides and second output tapered waveguides which are distributed in a staggered manner, the first output tapered waveguides and the second output tapered waveguides are positioned on two sides of the input tapered waveguides, the input tapered waveguides taper along the light transmission direction, and the first output tapered waveguides and the second output tapered waveguides taper along the opposite direction of the light transmission direction; the second coupling region comprises a first output straight waveguide, a second output straight waveguide and a second sub-wavelength grating, wherein the first output straight waveguide and the second output straight waveguide are arranged in parallel, the second sub-wavelength grating is distributed between the first output straight waveguide and the second output straight waveguide, the first output straight waveguide is connected with the first output conical waveguide, and the second output straight waveguide is connected with the second output conical waveguide; The first sub-wavelength grating and the second sub-wavelength grating are vertically arranged along the light transmission direction, and the period and the filling factor of the first sub-wavelength grating and the second sub-wavelength grating are the same.
  2. 2. The ultra-thin waveguide optical power splitter of claim 1, wherein the input tapered waveguide, the first output tapered waveguide, and the second output tapered waveguide have the same tapered structure with a tip width of 100 nm and a base width of 800 nm.
  3. 3. The optical power splitter based on a tapered ultra-thin waveguide with sub-wavelength grating enhancement according to claim 1, wherein the first coupling region has an axisymmetric structure or a non-axisymmetric structure, and the second coupling region has an axisymmetric structure, and a symmetry axis of the axisymmetric structure is parallel to the optical transmission direction.
  4. 4. The optical power splitter based on the sub-wavelength grating enhanced tapered ultra-thin waveguide according to claim 3, wherein when the first coupling region is in an axisymmetric structure, the distance between two adjacent tapered waveguides in the input tapered waveguide, the first output tapered waveguide and the second output tapered waveguide is 100-150 nm.
  5. 5. The optical power splitter based on a sub-wavelength grating enhanced tapered ultra-thin waveguide according to claim 3, wherein when the first coupling region is of a non-axisymmetric structure, a distance between the input tapered waveguide and the first output tapered waveguide is 0.1-2.1 μm, and a distance between the input tapered waveguide and the second output tapered waveguide is 100 nm; or, when the first coupling region is of a non-axisymmetric structure, the distance between the input tapered waveguide and the first output tapered waveguide is 100 nm, and the distance between the input tapered waveguide and the second output tapered waveguide is 100 nm.
  6. 6. The optical power splitter based on a tapered ultra-thin waveguide with sub-wavelength grating enhancement as claimed in claim 1, wherein the filling factor of the first sub-wavelength grating and the second sub-wavelength grating is 0.43-0.52, and/or, The first sub-wavelength grating and the second sub-wavelength grating have a period of 200 nm, and/or, The number of periods of the first sub-wavelength grating is 19 or 23, and the number of periods of the second sub-wavelength grating is 6.
  7. 7. The optical power splitter based on a sub-wavelength grating enhanced tapered ultra-thin waveguide according to claim 1, wherein the output waveguides comprise a first output waveguide and a second output waveguide, the first output waveguide and the second output waveguide being connected to the first output straight waveguide and the second output straight waveguide, respectively, with a predetermined distance therebetween.
  8. 8. The optical power divider based on the sub-wavelength grating enhanced tapered ultra-thin waveguide according to claim 7, wherein the output waveguide has an axisymmetric structure, and a symmetry axis of the axisymmetric structure is parallel to the optical transmission direction; The first output waveguide comprises a first output bent waveguide and a third output straight waveguide which are sequentially connected along the optical transmission direction; the second output waveguide comprises a second output bent waveguide and a fourth output straight waveguide which are sequentially connected along the optical transmission direction; The first output curved waveguide and the second output curved waveguide are both Bezier curves in shape.
  9. 9. The optical power divider based on the sub-wavelength grating enhanced tapered ultra-thin waveguide according to claim 7, wherein the output waveguide is an axisymmetric structure, a symmetry axis of the axisymmetric structure is parallel to the optical transmission direction, the first output waveguide comprises a fifth output straight waveguide, a first output curved waveguide and a third output straight waveguide which are sequentially connected along the optical transmission direction, the second output waveguide comprises a sixth output straight waveguide, a second output curved waveguide and a fourth output straight waveguide which are sequentially connected along the optical transmission direction, and the shapes of the first output curved waveguide and the second output curved waveguide are all bezier curves; Or alternatively, the first and second heat exchangers may be, The output waveguides are of axisymmetric structures, symmetry axes of the axisymmetric structures are parallel to the light transmission direction, the first output waveguides are formed by fifth output straight waveguides, and the second output waveguides are formed by sixth output straight waveguides.
  10. 10. A method of making a sub-wavelength grating-enhanced tapered ultra-thin waveguide based optical power splitter as claimed in any one of claims 1 to 9, comprising the steps of: and etching the top silicon layer by using the silicon on insulator as a material and adopting an electron beam lithography and reactive plasma etching method to prepare the optical power distributor.

Description

Optical power distributor based on sub-wavelength grating reinforced conical ultrathin waveguide and preparation method thereof Technical Field The invention relates to the technical field of optical communication devices, in particular to an optical power distributor based on a sub-wavelength grating reinforced conical ultrathin waveguide and a preparation method thereof. Background With the rapid development of data-intensive technologies such as 5G communication, artificial intelligence, quantum computation and the like, the traditional electronic interconnection faces the problems of limited bandwidth, low energy efficiency and the like. Photonic Integrated Circuits (PICs) are the preferred solution by virtue of ultra-high bandwidth and low delay, where silicon-based photonics is the mainstream integration platform due to compatibility with CMOS processes, high refractive index contrast, and mass production. Conventional 220 nm-thickness silicon waveguides have shortcomings in evanescent field utilization and process tolerance, and the silicon photonic platforms of ultrathin waveguide architectures are promoted. The thickness of the ultra-thin silicon waveguide can be lower than 100 nm, the side wall effect and transmission loss of TE modes can be obviously reduced, the ultra-thin silicon waveguide is suitable for light exchange, signal processing and other scenes, the light field extension proportion at the top of the waveguide is large, the ultra-thin silicon waveguide can be used for gas and biochemical sensing, meanwhile, the interaction between light and substances can be enhanced in the heterostructure of the ultra-thin silicon/low-dimensional material, the miniaturization of an active device is realized, and the signal integrity and the energy efficiency are improved. On the other hand, optical power splitters have been implemented in a variety of ways as core elements for on-chip signal processing and quantum integrated circuits. In terms of on-chip optical power splitter research, china academy of sciences Cheng Zhen et al, 2012, propose a 1×2 multimode interference (MMI) power splitter with an Insertion Loss (IL) of less than 0.1 dB [ IEEE Photonics Journal, 2012, 4 (6): 2272-2277 ] in the wavelength range 1530: 1530 nm to 1570 nm. The university of british columbia, canada Lukas Chrostowski et al propose an asymmetric waveguide-assisted 2 x 2 directional coupler to achieve arbitrary proportions of power splitting with insertion loss less than 1 dB and spectral bandwidth of 75 nm [ Optics Express, 2015, 23 (3): 3795]. Efstratios Skafidas to university of melbourne in 2016 et al proposes a power divider based on adiabatic tapered waveguides, which achieves adiabatic coupling and splitting of optical signals through three tapered waveguides, and has an insertion loss of less than 0.19 dB in the wavelength range of 1530 nm to 1600 nm. University of Shandong in 2018 Zhao Jia et al uses a multimode tapered branching waveguide as a Y-branch to achieve 50:50 power distribution, with a two output port power uniformity improvement of 4 dB and insertion loss of less than 0.6 dB [ Optik, 2019, 180:866-872 ]. All the optical power distributors are designed based on the traditional thick silicon waveguide architecture, and have the problems of insufficient process robustness, difficulty in simultaneously considering low loss, wide spectral bandwidth and high integration level. In terms of patents, liu Yong et al in 2018 Jiangsu Bay semiconductor technology, discloses a planar optical waveguide-based multipath Y-shaped optical path optical power divider chip (China utility model patent: CN 209117907U) capable of realizing multipath power division and reducing insertion loss and process difficulty, wang Xi et al in 2022 Jilin university discloses a MMI optical waveguide structure-based few-mode optical power divider (China utility model patent: CN 114153027A) which adopts an organic polymer as a waveguide material, can realize multimode power division, has lower cost and is suitable for batch preparation, and Su Bulan Ma Nian in 2022 grid core (U.S.) integrated circuit technology, incClischina Mu Erxi et al discloses an optical power divider (chinese patent No. CN115524787 a) comprising three tapered waveguide cores, which allows for customized splitting ratios by adjusting the overlap distance. The Y-type branch distributor has the advantages of simple structure and limited working bandwidth, the multimode interference type device relies on the self-imaging effect, has the defects of larger size, poor output power balance and the like, the directional coupler can adjust the splitting ratio through structural parameters and has obvious wavelength sensitivity, and the adiabatic coupler has the advantages of wide bandwidth, short coupling length and the like, but the conical tip and waveguide gap structure size is too narrow, and has lower tolerance to processing and manufacturing errors. Therefore, the method