CN109814202B - Non-reciprocal polarization beam splitter based on PT symmetry - Google Patents
Non-reciprocal polarization beam splitter based on PT symmetry Download PDFInfo
- Publication number
- CN109814202B CN109814202B CN201910243803.2A CN201910243803A CN109814202B CN 109814202 B CN109814202 B CN 109814202B CN 201910243803 A CN201910243803 A CN 201910243803A CN 109814202 B CN109814202 B CN 109814202B
- Authority
- CN
- China
- Prior art keywords
- stage
- directional coupler
- waveguide
- mode
- symmetrical directional
- 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
Abstract
The invention discloses a PT symmetry-based non-reciprocal polarization beam splitter. Comprises a three-stage PT symmetrical directional coupler; the output of a first loss single-mode waveguide of the first-stage PT symmetrical directional coupler is connected with the input of a second loss single-mode waveguide of the second-stage PT symmetrical directional coupler through a loss bent waveguide, and the first-stage PT symmetrical directional coupler is connected with the third-stage PT symmetrical directional coupler through a gain multi-mode waveguide and then connected with a second gain multi-mode waveguide through a gain bent waveguide; TE is realized by gain single-mode waveguide of second-stage PT symmetrical directional coupler0Outputting a mode; third-loss single-mode waveguide implementation TM of third-stage PT symmetrical directional coupler0Outputting a mode; a three-stage PT symmetrical directional coupler is utilized, and the imaginary part of the refractive index of the waveguide is adjusted through optical pumping, so that the nonreciprocal polarization beam splitter is formed. Based on PT symmetrical principle, light can only be transmitted in gain waveguide in a broken state, so that nonreciprocal transmission is realized, and influence of reflected light is effectively inhibited.
Description
Technical Field
The invention relates to a polarization beam splitter, in particular to a non-reciprocal polarization beam splitter based on PT symmetry.
Background
Since the 21 st century, people have increasingly increased demands for information processing and transmission, large-scale integrated circuits based on electrical interconnection play a crucial role, but the traditional electrical interconnection gradually goes to a bottleneck, researchers propose solutions based on optical interconnection, and construct integrated optoelectronics by combining with mature semiconductor processes, so that photonic integrated circuits with low cost, low power consumption, high integration level and high bandwidth can be manufactured, and the photonic integrated circuits are laid for the development of the future optical communication field, and have a very good application prospect. In the field of optical communications, a polarization beam splitter is a very important functional device, and can separate a TE mode from a TM mode, thereby achieving better control of an optical subsystem. The existing polarization beam splitter mainly comprises a waveguide coupling type polarization beam splitter and a grating coupling type polarization beam splitter, wherein the waveguide coupling type polarization beam splitter is based on a coupling mode theory, has a simple structure and is easy to design, so that the polarization beam splitter is widely applied.
In future optical interconnect systems, non-reciprocal devices also play a very important role in order to achieve arbitrary optical operation. A great deal of research has been carried out on polarizing beam splitters based on silicon materials, and many results have been achieved, but the devices still cannot avoid the influence of reflected light. At present, the realization of a non-reciprocal device is mainly realized by utilizing the Faraday effect, but the realization needs an external strong magnetic field and is not convenient for on-chip integration. Researchers find that by utilizing the special property of space-time (PT) symmetry, the system can enter a broken state by adjusting the broken condition in the PT symmetrical system, namely the gain/loss coefficient of a waveguide medium, so that the transmission state of light is changed, and nonreciprocal light transmission is realized. Therefore, PT symmetry is combined with the traditional waveguide coupling type polarization beam splitter, the small size convenient for integration is realized, and the non-reciprocal polarization beam splitter based on PT symmetry has great significance.
Disclosure of Invention
How to realize the polarization beam splitter with simple structure and the non-reciprocal PT symmetrical directional coupler are important problems for the research of the non-reciprocal polarization beam splitter. The invention aims to provide a PT symmetry-based non-reciprocal polarization beam splitter.
In order to achieve the purpose of the invention, the invention adopts the technical scheme that:
the invention comprises a first-stage PT symmetrical directional coupler, a second-stage PT symmetrical directional coupler and a third-stage PT symmetrical directional coupler; the output of a first loss single-mode waveguide of the first-stage PT symmetrical directional coupler is connected with the input of a second loss single-mode waveguide of the second-stage PT symmetrical directional coupler through a loss bent waveguide, and the first-stage PT symmetrical directional coupler and the third-stage PT symmetrical directional coupler are connected through a gain multi-mode waveguide and then connected with a second gain multi-mode waveguide through a gain bent waveguide; TE is realized by gain single-mode waveguide of second-stage PT symmetrical directional coupler0Outputting the mode; third-loss single-mode waveguide implementation TM of third-stage PT symmetrical directional coupler0Outputting the mode; and utilizing the three-stage PT symmetrical directional coupler, and adjusting the imaginary part of the refractive index of the waveguide through optical pumping so as to form the nonreciprocal polarization beam splitter.
The first stage PT symmetric orientationThe coupler and the third-stage PT symmetric directional coupler are multimode directional couplers, and respectively comprise a gain multimode waveguide and a loss single-mode waveguide, TM0Propagation constant and TM of mode in lossy single-mode waveguide1The propagation constants of the modes in the gain multimode waveguide are the same.
The second-stage PT symmetrical directional coupler is a single-mode directional coupler, the upper part of the second-stage PT symmetrical directional coupler is a gain single-mode waveguide, and the lower part of the second-stage PT symmetrical directional coupler is a loss single-mode waveguide.
The coupling region waveguide lengths of the first stage PT symmetrical directional coupler, the second stage PT symmetrical directional coupler and the third stage PT symmetrical directional coupler are all a coupling length.
The invention has the beneficial effects that:
1) TE of the invention0Mode and TM0The directional coupler is adopted for mode separation, so that the insertion loss is small;
2) based on the PT symmetrical principle, the invention utilizes the three-stage PT symmetrical directional coupler, and light can only be transmitted in the gain waveguide in a broken state, thereby realizing non-reciprocal transmission and effectively inhibiting the influence of reflected light;
3) the manufacturing process of the device is compatible with the current CMOS process, and the device has a simple structure and is easy to manufacture.
Drawings
Fig. 1 is a schematic diagram of the overall structure of a non-reciprocal polarization beam splitter.
FIG. 2 is a diagram of input TE from a non-reciprocal polarizing beamsplitter before it is broken0Mode time optical field profile.
FIG. 3 is a diagram of input waveguide input TM before a non-reciprocal polarizing beamsplitter is broken0Mode time optical field profile.
FIG. 4 shows reverse input TE from a non-reciprocal polarizing beamsplitter after it is broken0Mode time optical field profile.
FIG. 5 is a schematic diagram of a non-reciprocal polarizing beamsplitter with a broken reverse input TM0Mode time optical field profile.
In the figure: 1. a first loss single-mode waveguide, 2, a loss bent waveguide, 3, a second loss single-mode waveguide, 4, a gain single-mode waveguide, 5, a second gain multi-mode waveguide, 6, a gain bent waveguide, 7, a first gain multi-mode waveguide, 8, a third loss single-mode waveguide, 9, a first PT symmetrical directional coupler, 10, a second PT symmetrical directional coupler, 11, a third PT symmetrical directional coupler
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
As shown in fig. 1, the present invention includes a first stage PT symmetric directional coupler 9, a second stage PT symmetric directional coupler 11 and a third stage PT symmetric directional coupler 10; the output of a first loss single-mode waveguide 1 of a first-stage PT symmetrical directional coupler 9 is connected with the input of a second loss single-mode waveguide 3 of a second-stage PT symmetrical directional coupler 11 through a loss bent waveguide 2, and the first-stage PT symmetrical directional coupler 9 and a third-stage PT symmetrical directional coupler 10 are connected with a second gain multi-mode waveguide 5 through a gain bent waveguide 6 after being connected through a gain multi-mode waveguide 7; TE realization by gain single-mode waveguide 4 of second-stage PT symmetric directional coupler 110Outputting the mode; third loss single mode waveguide 8 of third stage PT symmetric directional coupler 10 implements TM0Outputting the mode; and utilizing the three-stage PT symmetrical directional coupler, and adjusting the imaginary part of the refractive index of the waveguide through optical pumping so as to form the nonreciprocal polarization beam splitter.
The first stage PT symmetrical directional coupler 9 and the third stage PT symmetrical directional coupler 10 are multimode directional couplers, and respectively comprise a gain multimode waveguide and a loss single mode waveguide, TM0Propagation constant and TM of mode in lossy single-mode waveguide1The propagation constants of the modes in the gain multimode waveguide are the same.
The second stage PT symmetric directional coupler 11 is a single-mode directional coupler, the upper part is a gain single-mode waveguide, and the lower part is a loss single-mode waveguide.
The coupling region waveguide lengths of the first stage PT symmetrical directional coupler 9, the second stage PT symmetrical directional coupler 11 and the third stage PT symmetrical directional coupler 10 are a coupling length.
The working principle of the invention is as follows:
the invention outputs the loss through the first loss single-mode waveguide 1 of the first-stage PT symmetrical directional coupler 9The dissipative bent waveguide 2 is connected with the input of a second loss single-mode waveguide 3 of a second-stage PT symmetrical directional coupler 11, and TE is realized through a gain single-mode waveguide 4 of the second-stage PT symmetrical directional coupler 110Outputting the mode; the first stage PT symmetrical directional coupler 9 is connected with the third stage PT symmetrical directional coupler 10 through the gain multi-mode waveguide 7, and the TM is realized through the third loss single-mode waveguide 8 of the third stage PT symmetrical directional coupler 100Outputting the mode; the size of the imaginary part of the refractive index of the waveguide is adjusted through optical pumping, so that the three-stage PT symmetrical directional coupler enters a broken state, and the nonreciprocal polarization beam splitter is realized.
The width of the gain multimode waveguide 7 in the first stage PT symmetrical directional coupler 9 is larger than that of the first loss single-mode waveguide 1, and TM meeting the phase matching condition and input from the first loss single-mode waveguide 1 in the first directional coupler 90A zero order mode coupled into the gain multimode waveguide 7 as TM1A first-order mode; TE0The zero order mode still transmits from the lossy single-mode waveguide 1 to the second lossy single-mode waveguide 3 of the second-stage PT symmetric directional coupler 11 via the lossy curved waveguide 2 because the phase matching condition is not satisfied. Wherein TM0Zeroth order mode and TM1The phase matching condition to be satisfied by the first-order mode is
Where β is the propagation constant.
The widths of the second loss single-mode waveguide 3 and the gain single-mode waveguide 4 in the second-stage PT symmetrical directional coupler 11 are the same, and the TE0TE output by the first stage PT symmetric directional coupler 9 with the zero order mode satisfying the phase matching condition0The zeroth order mode is coupled out into the gain single mode output waveguide 4 as shown in figure 2.
The width of the gain multimode waveguide 7 in the third-stage PT symmetrical directional coupler 10 is larger than that of the third-loss multimode waveguide 8, and TM output by the gain multimode waveguide 71The first-order mode satisfies the phase matching condition
Is coupled to a third lossy single-mode waveReduction to TM in channel 80Zero order mode output, thereby achieving polarization separation, as shown in fig. 3; the gain multimode waveguide 7 is connected to the second gain multimode waveguide 5 via the gain bend waveguide 6, reducing the effect of the invalid signal on the output in the third loss single mode waveguide 8.
The coupling region waveguide lengths of the first stage PT symmetrical directional coupler 9, the second stage PT symmetrical directional coupler 11 and the third stage PT symmetrical directional coupler 10 are respectively a coupling length under respective conditions, so that optical energy is coupled as much as possible, and loss is reduced.
The first stage PT symmetrical directional coupler 9, the second stage PT symmetrical directional coupler 11 and the third stage PT symmetrical directional coupler 10 are all PT symmetrical structures, and when the pump light power is low and PT symmetry does not enter a broken state, a forward polarization beam splitter can be realized; when the pump light power is large enough and PT symmetrically enters a defect state, the light can only be transmitted in the gain waveguide, thereby forming TE for reverse input0Zeroth order mode and TM0Suppression of the zero order mode realizes a non-reciprocal polarizing beam splitter as shown in fig. 4 and 5.
The device structure manufacturing of the embodiment of the invention can be implemented by, but not limited to, the following modes:
the process flow adopts III-V group mixed material (InGaAsP). After the surface of the wafer is cleaned, the process of the photoetching part adopts spin coating positive photoresist and drying as a mask, and a required waveguide pattern is formed by ultraviolet exposure. And etching the III-V group mixed material by adopting ion beam assisted free radical etching (ICP) dry etching to form a 1-micron waveguide. And then, continuously making a photoetching mask on the waveguide layer, depositing metal Al as waveguide loss introduction, and stripping the metal Al layer to only leave the metal Al on the required loss waveguide. A protective layer of silicon dioxide of about 2 μm is then deposited over the waveguide layer. And finally, depositing metal Al on the silicon dioxide layer, performing photoetching mask, and performing metal etching on the Al to leave an optical pumping window for the gain waveguide. The width of the single-mode waveguide may be about 500nm, and the width of the multi-mode waveguide may be about 1180 nm. The gap width of the directional coupler is about 200nm, and the length of the coupling region is also a coupling length.
Claims (4)
1. A PT symmetry-based non-reciprocal polarization beam splitter is characterized in that: the system comprises a first-stage PT symmetrical directional coupler (9), a second-stage PT symmetrical directional coupler (11) and a third-stage PT symmetrical directional coupler (10); the output of a first loss single-mode waveguide (1) of a first-stage PT symmetrical directional coupler (9) is connected with the input of a second loss single-mode waveguide (3) of a second-stage PT symmetrical directional coupler (11) through a loss bent waveguide (2), and the first-stage PT symmetrical directional coupler (9) and a third-stage PT symmetrical directional coupler (10) are connected with a second gain multi-mode waveguide (5) through a gain multi-mode waveguide (7) and then connected with each other through a gain bent waveguide (6); TE is realized by a gain single-mode waveguide (4) of a second-stage PT symmetrical directional coupler (11)0Outputting the mode; third loss single mode waveguide (8) of third stage PT symmetric directional coupler (10) realizes TM0Outputting the mode; by utilizing the three-stage PT symmetrical directional coupler and adjusting the magnitude of the refractive index imaginary part of the waveguide through optical pumping, when the three-stage PT symmetrical directional coupler of the polarization beam splitter enters a broken state, the polarization beam splitter can inhibit reverse transmission, thereby realizing the nonreciprocal polarization beam splitter.
2. A PT symmetry based non-reciprocal polarizing beam splitter as claimed in claim 1, wherein: the first stage PT symmetrical directional coupler (9) and the third stage PT symmetrical directional coupler (10) are multimode directional couplers, and respectively comprise a gain multimode waveguide and a loss single mode waveguide, TM0Propagation constant and TM of mode in lossy single-mode waveguide1The propagation constants of the modes in the gain multimode waveguide are the same.
3. A PT symmetry based non-reciprocal polarizing beam splitter as claimed in claim 1, wherein: the second-stage PT symmetrical directional coupler (11) is a single-mode directional coupler, the upper part of the second-stage PT symmetrical directional coupler is a gain single-mode waveguide, and the lower part of the second-stage PT symmetrical directional coupler is a loss single-mode waveguide.
4. A PT symmetry based non-reciprocal polarizing beam splitter as claimed in claim 1, wherein: the coupling region waveguide lengths of the first stage PT symmetrical directional coupler (9), the second stage PT symmetrical directional coupler (11) and the third stage PT symmetrical directional coupler (10) are all a coupling length.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910243803.2A CN109814202B (en) | 2019-03-28 | 2019-03-28 | Non-reciprocal polarization beam splitter based on PT symmetry |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910243803.2A CN109814202B (en) | 2019-03-28 | 2019-03-28 | Non-reciprocal polarization beam splitter based on PT symmetry |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109814202A CN109814202A (en) | 2019-05-28 |
| CN109814202B true CN109814202B (en) | 2020-04-28 |
Family
ID=66610820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910243803.2A Active CN109814202B (en) | 2019-03-28 | 2019-03-28 | Non-reciprocal polarization beam splitter based on PT symmetry |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109814202B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110542950B (en) * | 2019-07-18 | 2023-11-07 | 北京大学 | Mode demultiplexer of degenerated mode group based on space three-dimensional waveguide |
| US11637355B1 (en) | 2020-08-26 | 2023-04-25 | Washington University | Fully integrated parity-time symmetric electronics |
| CN112162352A (en) * | 2020-09-09 | 2021-01-01 | 山东建筑大学 | Continuously adjustable splitting ratio directional coupler based on space scale-time symmetry |
| CN112462534B (en) * | 2020-12-21 | 2022-04-29 | 华中科技大学 | Ultra-close range metal electrode thermal modulation phase shifter |
| CN112904478B (en) * | 2021-03-31 | 2021-12-03 | 西南交通大学 | U-shaped waveguide connected two-stage asymmetric directional coupler type light polarization beam splitting rotator |
| CN116027483B (en) * | 2023-03-28 | 2023-06-30 | 济南量子技术研究院 | Polarization beam splitter based on lithium niobate thin film ridge waveguide |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4978189A (en) * | 1989-11-14 | 1990-12-18 | At&T Bell Laboratories | Hybrid optical isolator, circulator or switch, and systems utilizing same |
| CN100371775C (en) * | 2006-04-10 | 2008-02-27 | 浙江大学 | Waveguide type non-reciprocal beam splitter member |
| JP6198091B2 (en) * | 2013-12-25 | 2017-09-20 | 華為技術有限公司Ｈｕａｗｅｉ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｃｏ．，Ｌｔｄ． | Waveguide polarization splitter and polarization rotator |
| CN106405733B (en) * | 2016-10-26 | 2019-02-15 | 浙江大学 | A kind of polarization beam splitting-bundling device |
-
2019
- 2019-03-28 CN CN201910243803.2A patent/CN109814202B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109814202A (en) | 2019-05-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109814202B (en) | Non-reciprocal polarization beam splitter based on PT symmetry | |
| JP6198091B2 (en) | Waveguide polarization splitter and polarization rotator | |
| US9128242B2 (en) | Mode-evolution compound converter | |
| CN108983352B (en) | End face coupler and preparation method thereof | |
| CN109031518B (en) | Cantilever type end face coupler | |
| SG181649A1 (en) | Photonic integrated circuit having a waveguide-grating coupler | |
| CN109581586B (en) | Compact structure type silicon nitride wavelength division multiplexing photon chip | |
| CN105866885B (en) | Polarization beam splitting rotator | |
| CN112711093B (en) | Polarization beam splitter structure and polarization beam splitting method | |
| CN108646346A (en) | A kind of narrow band filter based on phase-modulation apodization grating | |
| CN112051641A (en) | Inclined grating type polarization beam splitter applying slit waveguide structure and manufacturing method | |
| US11808976B2 (en) | Compact on-chip polarization splitter-rotator based on Bezier curve gradient waveguide | |
| Van der Tol et al. | Realization of a short integrated optic passive polarization converter | |
| CN110780381A (en) | Polarization beam splitter with asymmetric three-waveguide structure and preparation method thereof | |
| CN204129403U (en) | Based on the all-optical XOR logic door of vertical coupled micro-cyclic laser optical bistability | |
| CN112526675B (en) | W-shaped silicon groove type on-chip polarization rotator based on mode mixing principle | |
| CN113189708B (en) | Polarization insensitive directional coupler structure and method | |
| CN115755275B (en) | Miniaturized slit waveguide mode conversion device based on sub-wavelength structure | |
| CN116520493A (en) | TE mode and TM mode separated polarization beam splitter chip based on film lithium niobate | |
| CN110989080B (en) | Grating auxiliary polarizer based on reverse coupling principle | |
| CN109471273A (en) | A kind of silicon substrate polarization rotator and its method for controlling optical signal polarization state | |
| CN104360561B (en) | Based on the bistable all-optical XOR logic door of vertical coupled micro-loop laser optical | |
| CN110554458B (en) | Symmetrical three-waveguide type polarization beam splitter based on sub-wavelength structure | |
| CN113253384B (en) | Polarization beam splitter structure with high extinction ratio | |
| CN113109902A (en) | Lithium niobate thin film polarization concentrator on chip and preparation method thereof |
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 |