CN114488405B - Design method of double-waveguide adiabatic mode coupler - Google Patents
Design method of double-waveguide adiabatic mode coupler Download PDFInfo
- Publication number
- CN114488405B CN114488405B CN202210129395.XA CN202210129395A CN114488405B CN 114488405 B CN114488405 B CN 114488405B CN 202210129395 A CN202210129395 A CN 202210129395A CN 114488405 B CN114488405 B CN 114488405B
- Authority
- CN
- China
- Prior art keywords
- waveguide
- mode
- mode coupler
- adiabatic mode
- diagonal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0075—Arrangements of multiple light guides
- G02B6/0078—Side-by-side arrangements, e.g. for large area displays
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
Abstract
The invention discloses a design method of a double-waveguide adiabatic mode couplerThe double-waveguide heat-insulating mode coupler is a curved waveguide structure and is formed by connecting a plurality of oblique line segments along the propagation direction of light beams, and local mode coupling coefficient kappa is utilized during design 12 The length of each section is selected to be a proper inclination angle by 0, and then the oblique line sections are spliced together to form a complete device, so that the length of the device is shortened compared with a double-waveguide adiabatic mode coupler in which an initial end and an end are connected in a straight line, and the design method is simple. Such a compact adiabatic mode coupler can be a critical component of a photonic integrated circuit system.
Description
Technical Field
The invention relates to a design method of a double-waveguide adiabatic mode coupler.
Background
The adiabatic device is a connector for connecting various optical functional units in the photonic integrated circuit, and plays an important role in future large-scale photonic integrated chips. Photonic integrated circuits are evolving towards higher levels of integration, including multi-layer meaning: (1) the individual optics have smaller dimensions; (2) more functional devices are integrated on a single chip. In addition, silicon photonics is one of the hot research fields of integrated optics, and the silicon material and photonics are combined together to research the manufacture and integration of various photon function devices on the silicon material or the silicon-based material. Adiabatic mode couplers are common ways of achieving light splitting and light combining in fiber systems, and can evolve an input mode in one waveguide into a symmetrical mode and an input mode in a second waveguide into an antisymmetric mode on a phase matching plane.
In designing adiabatic mode couplers, the length of the device obtained in this way can be significantly beyond that required, although the total length of the scan of the waveguide structure can be simply changed linearly to obtain the required device length for a particular transmission power. The existing design of the adiabatic mode coupler is based on the analytic solution of an equation set, is generally complex, is not easy to use, needs some assumptions and approximations, causes the accuracy to be affected to a certain extent, and is difficult to be used for the design of a complex structure.
Disclosure of Invention
The invention aims to: aiming at the prior art, a design method of the double-waveguide adiabatic mode coupler is provided, so that the designed adiabatic mode coupler has a compact structure.
The technical scheme is as follows: the design method of the double-waveguide adiabatic mode coupler is characterized in that the double-waveguide adiabatic mode coupler is of a bent waveguide structure and is formed by connecting a plurality of oblique line segments along the propagation direction of a light beam; initial conditions of the design method include initial end widths of two waveguides, end widths, a gap between the two waveguides, the number of diagonal segments constituting the dual-waveguide adiabatic mode coupler, and lengths of the respective diagonal segments, the design method including: for each diagonal segment, the local mode coupling coefficient κ at the center cross-section is calculated according to the following formula 12 ；
Wherein c is the speed of light in vacuum, n 1 For mode 1 effective index at center cross section, n 2 For the effective refractive index of mode 2 at the center cross section, L is the length of the diagonal segment, θ is the inner sidewall tilt angle of the diagonal segment, w t1 、w t2 The widths of two ends of one of the waveguides in the oblique line segment, e 1 (y m )、e 2 (y m ) The electric field strengths, y, of mode 1 and mode 2, respectively m (x) Respectively the coordinates of the electric field on the side wall of the waveguide, delta epsilon m Is the variation of dielectric constant on the side wall of the oblique line section; m=1, 2,3,4, representing the inner and outer sidewalls of the two waveguides;
let the coupling coefficient kappa 12 =0, obtaining the inner wall inclination angle θ of the diagonal segment; all diagonal segments are spliced together to form a complete dual waveguide adiabatic mode coupler shape.
Further, the number of diagonal segments constituting the dual-waveguide adiabatic mode coupler is 3 or more.
The beneficial effects are that: the double-waveguide adiabatic mode coupler is a bent waveguide structure and is formed by connecting a plurality of oblique line segments along the propagation direction of light beams, and local mode coupling coefficient kappa is utilized during design 12 =0 selecting a suitable angle of inclination for the length of each segment, and then splicing the oblique segments togetherThe length of the device is shortened and the design method is simple compared with a double-waveguide adiabatic mode coupler with the initial end and the tail end connected in a straight line. Such a compact adiabatic mode coupler can be a critical component of a photonic integrated circuit system.
Drawings
FIG. 1 is a schematic diagram of the initial end structure of a dual waveguide adiabatic mode coupler;
FIG. 2 is a schematic diagram of the end structure of a dual waveguide adiabatic mode coupler;
FIG. 3 is a schematic top view of a dual waveguide adiabatic mode coupler with straight line connection between the beginning and end;
FIG. 4 is a schematic top view of a dual waveguide adiabatic mode coupler according to the present invention;
FIG. 5 is a schematic diagram of a diagonal segment;
FIG. 6 is a transmission graph of a dual waveguide adiabatic mode coupler in an embodiment.
Detailed Description
The invention is further explained below with reference to the drawings.
This embodiment illustrates the design process by using an adiabatic mode coupler fabricated on a silicon waveguide plate on a silicon thin film substrate.
As shown in fig. 1 and 2, which are schematic diagrams of the initial end and the final end of the dual-waveguide adiabatic mode coupler, the dual-waveguide adiabatic mode coupler is designed to connect the initial end and the final end and transmit the energy from the initial end to the final end in a shortest distance as possible. The substrate 2 of the structure is silicon dioxide, the core 1 of the structure is silicon, the cladding 3 of the structure is air, wherein the refractive index n of the silicon dioxide SiO2 Refractive index n of silicon = 3.455 Si Refractive index n of air = 3.455 Air =1. In this embodiment, the silicon dioxide thickness is 2 μm, the silicon thickness h=220 nm, the initial end widths of the two waveguides are 220nm and 100nm, the end widths of the two waveguides are 160nm, the gap g=100 nm between the two silicon waveguides, and the wavelength of the light beam is 1.55 μm.
FIG. 3 shows a dual waveguide adiabatic mode coupler with a straight line connection, a configuration that is generallyA long length is required. In order to realize a compact adiabatic mode coupler, as shown in fig. 4, the dual waveguide adiabatic mode coupler of the present invention has a curved waveguide structure, and is formed by connecting a plurality of diagonal segments along the propagation direction of a light beam as shown in fig. 5. In FIG. 4, the opposing inner walls of the two waveguides remain parallel and the opposing outer walls of the two waveguides remain parallel, i.e., the outer side wall of the first waveguide is inclined at an angle θ 1 Angle of inclination θ with the outer sidewall of the second waveguide 4 In conformity with the inner sidewall inclination angle theta of the first waveguide 2 Angle of inclination θ with the inner sidewall of the second waveguide 3 And consistent.
As shown in fig. 5, for a diagonal segment, the local mode coupling coefficient κ from mode 1 to mode 2 at the center cross section 12 The expression is:
wherein ω is angular frequency, β 1 ＝ωn 1 /c、β 2 ＝ωn 1 And/c is the phase constant of mode 1 and mode 2, respectively, c is the speed of light in vacuum, n 1 For mode 1 effective index at center cross section, n 2 For mode 2 effective index at center cross section, e 1 (y m )、e 2 (y m ) The electric field strengths, y, of mode 1 and mode 2, respectively m (x) Respectively the coordinates of the electric field on the side wall of the waveguide, delta epsilon m For the variation of dielectric constants on the sidewalls of the diagonal line segments, m=1, 2,3,4 correspond to the outer sidewall of the first waveguide, the inner sidewall of the second waveguide, and the outer sidewall of the second waveguide in order, respectively.
By geometrical derivation, the relationship of the inclination angle and the diagonal segment length L can be deduced:
tanθ 2 ＝tanθ 3 ＝tanθ (2)
wherein w is t1 、w t2 Respectively the widths of the two ends of the second waveguide in the diagonal segment, theta is the inclination angle of the inner side wall of the diagonal segment, and theta 2 ＝θ 3 ＝θ。
Bringing formulae (2) and (3) into formula (1) gives:
wherein, delta epsilon m For the variation of dielectric constant on the side wall of the oblique line section, m=1, 2,3,4 correspond to the outer side wall of the first waveguide, the inner side wall of the second waveguide and the outer side wall of the second waveguide in sequence respectively.
When the coupling coefficient is kappa 12 When=0, mode transmission is lossless. In this example, the adiabatic coupler is divided into 4 segments, and the length of each segment is selected to be 0.1 μm, so that κ in equation (4) 12 The inclination angle θ of the inner sidewall of each diagonal segment can be obtained by=0, so as to obtain the specific shape of each diagonal segment. All diagonal segments are spliced together to form a complete dual waveguide adiabatic mode coupler shape.
It should be noted that the selection of the length and the inclination angle of each diagonal section of the adiabatic mode coupler is not unique, so long as equation (4) is satisfied.
The total length of the device is scanned to obtain the transmission curve of the complete dual waveguide adiabatic mode coupler, as shown in fig. 6. Comparing the dual waveguide adiabatic mode coupler of the present embodiment with the case of straight line connection of the initial and final ends, as can be seen from fig. 6, the adiabatic mode coupler of the present invention is much shorter in length than the case of straight line based on the same power transmission. At 99.5% power transmission, for example, the total length required for the present invention is 9 μm, in the case of a straight line 19 μm. Therefore, in the case of 99.5% power transfer, the length of the straight line is more than 2 times of the length required by the invention, which indicates that the length of the designed adiabatic mode coupler can be very short, and the miniaturization of the device is realized.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (2)
1. The design method of the double-waveguide adiabatic mode coupler is characterized in that the double-waveguide adiabatic mode coupler is of a bent waveguide structure and is formed by connecting a plurality of oblique line segments along the propagation direction of light beams; initial conditions of the design method include initial end widths of two waveguides, end widths, a gap between the two waveguides, the number of diagonal segments constituting the dual-waveguide adiabatic mode coupler, and lengths of the respective diagonal segments, the design method including: for each diagonal segment, the local mode coupling coefficient κ at the center cross-section is calculated according to the following formula 12 ；
Wherein c is the speed of light in vacuum, n 1 For mode 1 effective index at center cross section, n 2 For the effective refractive index of mode 2 at the center cross section, L is the length of the diagonal segment, θ is the inner sidewall tilt angle of the diagonal segment, w t1 、w t2 The widths of two ends of one of the waveguides in the oblique line segment, e 1 (y m )、e 2 (y m ) The electric field strengths, y, of mode 1 and mode 2, respectively m (x) Respectively the coordinates of the electric field on the side wall of the waveguide, delta epsilon m Is the variation of dielectric constant on the side wall of the oblique line section; m=1, 2,3,4, respectively corresponding to the outer side wall of the first waveguide, the inner side wall of the second waveguide, and the outer side wall of the second waveguide in sequence;
let the coupling coefficient kappa 12 =0, obtaining the inner wall inclination angle θ of the diagonal segment; all diagonal segments are spliced together to form a complete dual waveguide adiabatic mode coupler shape.
2. The method of designing a dual waveguide adiabatic mode coupler according to claim 1, wherein the number of diagonal segments constituting the dual waveguide adiabatic mode coupler is 3 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210129395.XA CN114488405B (en) | 2022-02-11 | 2022-02-11 | Design method of double-waveguide adiabatic mode coupler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210129395.XA CN114488405B (en) | 2022-02-11 | 2022-02-11 | Design method of double-waveguide adiabatic mode coupler |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114488405A CN114488405A (en) | 2022-05-13 |
| CN114488405B true CN114488405B (en) | 2023-06-30 |
Family
ID=81479943
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210129395.XA Active CN114488405B (en) | 2022-02-11 | 2022-02-11 | Design method of double-waveguide adiabatic mode coupler |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114488405B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115494586B (en) * | 2022-10-26 | 2023-06-30 | 南通大学 | Double-waveguide adiabatic coupler |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6741782B2 (en) * | 2000-07-31 | 2004-05-25 | Spectalis Corp. | Optical waveguide structures |
| US7853108B2 (en) * | 2006-12-29 | 2010-12-14 | Massachusetts Institute Of Technology | Fabrication-tolerant waveguides and resonators |
| JP6424018B2 (en) * | 2014-06-06 | 2018-11-14 | 株式会社フジクラ | Mode conversion element and optical waveguide element |
| JP6492437B2 (en) * | 2014-07-22 | 2019-04-03 | 沖電気工業株式会社 | Directional coupler and design method thereof, optical waveguide device, and wavelength filter |
| US9442250B2 (en) * | 2014-07-31 | 2016-09-13 | The Regents Of The University Of California | Waveguide arrangements based on adiabatic elimination |
| JP6047527B2 (en) * | 2014-08-14 | 2016-12-21 | 株式会社フジクラ | Substrate type optical waveguide device |
| US9810839B2 (en) * | 2015-03-09 | 2017-11-07 | Artic Photonics Inc. | Controlled tunneling waveguide integration (CTWI) for effective coupling between different components in a photonic chip |
-
2022
- 2022-02-11 CN CN202210129395.XA patent/CN114488405B/en active Active
Non-Patent Citations (1)
| Title |
|---|
| 光纤耦合器的理论、设计及进展;林锦海;张伟刚;;物理学进展(第01期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114488405A (en) | 2022-05-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9851504B2 (en) | Planar optical waveguide device, DP-QPSK modulator, coherent receiver, and polarization diversity | |
| US6621972B2 (en) | Optical waveguides with trench structures | |
| US20180180818A1 (en) | Optical Edge Coupler with Controllable Mode Field for Photonic Chip | |
| US20160062038A1 (en) | Planar optical waveguide element, dual polarization quadrature phase shift keying modulator, coherent receiver, and polarization diversity | |
| US9835798B2 (en) | Planar optical waveguide device, polarization multiplexing 4-value phase modulator, coherent receiver, and polarization diversity | |
| CN109407229B (en) | End face coupler | |
| US10809456B2 (en) | Adiabatically coupled photonic systems with fan-out interposer | |
| CN114167545B (en) | Design method of ultra-compact adiabatic mode coupler | |
| CN114114540B (en) | Design method of efficient compact adiabatic mode converter | |
| CN114488389A (en) | Adiabatic guided wave system | |
| CN114488405B (en) | Design method of double-waveguide adiabatic mode coupler | |
| CN117222925A (en) | Photonic module and method of manufacture | |
| CN114895402A (en) | Thermal insulation guided wave system of skew | |
| US10746935B2 (en) | Fiber-to-waveguide coupling with high alignment tolerance | |
| CN112470047B (en) | Silicon dioxide to silicon nitride PLC wave mode converter for hybrid device | |
| US20240069286A1 (en) | Dual Layer Optical Coupling Configuration Between Photonic Integrated Circuit And External Single Mode Optical Fiber | |
| US20230280524A1 (en) | Optical Waveguide Device and Method for Manufacturing the Same | |
| US10802214B2 (en) | Adiabatically coupled photonic systems with vertically tapered waveguides | |
| CN115494586B (en) | Double-waveguide adiabatic coupler | |
| JP6991259B2 (en) | Optical waveguide element | |
| JP5222791B2 (en) | Optical waveguide | |
| US20240036263A1 (en) | Diamond spot size converter for fiber edge coupling | |
| WO2014156959A1 (en) | Optical end coupling type silicon optical integrated circuit | |
| CN116794768A (en) | Adiabatic mode coupler | |
| CN117092748A (en) | Compact adiabatic mode evolution ware |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |