阅读说明：本技术 一种基于相变材料调控的y分支波导结构偏振分束器 (Y-branch waveguide structure polarization beam splitter based on phase change material regulation ) 是由 刘富荣 谢轩轩 张永志 陈清远 张露露 连阳波 于 2021-08-28 设计创作，主要内容包括：一种基于相变材料调控的Y分支波导结构偏振分束器,属于光器件应用和信息处理技术领域。偏振分束器包括基底、Y分支光波导和相变材料薄膜。相变材料薄膜分别呈单层上贴式和两个单层侧贴式沉积在Y分支波导上,通过波导中的倏逝场耦合作用可以改变相变材料薄膜的状态,调整混合光波导的尺寸可以将TM/TE偏振模式分离输出。相变材料薄膜在晶态和非晶态的光学常数存在巨大差异,可以改变光波导中的光传播行为。利用有效折射率的不同就可以实现偏振态输出和截止。本发明基于Si波导和相变材料的非易失性超快相变偏振分束器,实现器件的低损耗和微型化,设计结构简单,便于集成,为未来全光器件的发展奠定了基础。(A Y-branch waveguide structure polarization beam splitter based on phase change material regulation belongs to the technical field of optical device application and information processing. The polarization beam splitter includes a substrate, a Y-branch optical waveguide, and a phase change material film. The phase-change material film is respectively deposited on the Y-branch waveguide in a single-layer top-mounted mode and two single-layer side-mounted modes, the state of the phase-change material film can be changed through evanescent field coupling in the waveguide, and TM/TE polarization modes can be separated and output by adjusting the size of the mixed optical waveguide. The phase change material film has great difference in optical constants of crystalline state and amorphous state, and can change the light propagation behavior in the optical waveguide. Polarization state output and cut-off can be achieved by utilizing the difference of effective refractive indexes. The non-volatile ultrafast phase change polarization beam splitter based on the Si waveguide and the phase change material realizes low loss and miniaturization of devices, has a simple design structure, is convenient to integrate, and lays a foundation for the development of future all-optical devices.)

1. A polarization beam splitter of a Y-branch waveguide structure based on phase change material regulation is characterized in that mode selection is carried out by utilizing the change of effective refractive index after a phase change material film is introduced into a waveguide; the phase-change optical waveguide comprises a substrate, a Y-branch optical waveguide and a phase-change material film, wherein the Y-branch optical waveguide is arranged on the substrate, a layer of phase-change material film is coated on the upper surface of one branch of the Y-branch optical waveguide, and the branch is marked as an output 1 branch; coating a layer of phase change material film on the left side and the right side of the other branch of the Y-branch optical waveguide respectively, wherein the branch is marked as an output 2 branch; modulating the mode of light in the Y-branch waveguide; phase change material X_mSb_nTe_kWherein X is a sulfur-series element.

2. The polarization beam splitter of claim 1, wherein the phase change material is selected from Ge₂Sb₂Te₅、Ge₁Sb₂Te₄、GeTe、Sb₂Te₃、Sc_0.2Sb₂Te₃And the like.

3. The polarization beam splitter of a Y-branch waveguide structure based on phase change material modulation of claim 1, wherein the Y-branch optical waveguide is divided into three parts, a first part is a total convergence section of Y for input, a middle part is a V-shaped structure forming a Y-structure with the first part, and a third part is an output end extending from the end of the V-shaped structure in parallel with the total convergence section; the phase change material films on the Y-branch optical waveguide branches are respectively positioned at one end of the output end close to the V-shaped structure.

4. The polarization beam splitter of Y-branch waveguide structure based on phase change material manipulation according to claim 3, wherein the length of the phase change material film is smaller than the length of the output end, preferably 1000 nm.

5. The polarization beam splitter of Y-branch waveguide structure based on phase change material modulation as claimed in claim 3, wherein the width of the phase change material film attached to the upper surface of the output 1 branch is equal to the width of the corresponding output end, and the thickness of the phase change material film is selected to be 25 nm.

6. The polarization beam splitter of the Y-branch waveguide structure based on the phase change material regulation and control of claim 3, wherein the height of the phase change material film attached to the left and right sides of the output 1 branch is equal to the height of the corresponding output end, and the thickness of the phase change material film is selected to be 30 nm.

7. The polarization beam splitter of a Y-branch waveguide structure based on phase change material manipulation of claim 3, wherein the height, i.e., thickness, of the Y-branch optical waveguide is selected to be 340nm and the width of each segment is selected to be 500 nm.

8. The polarization beam splitter of the Y-branch waveguide structure based on phase change material regulation and control as claimed in any one of claims 1 to 7, wherein the phase state of the phase change material on the two branches is converted from amorphous state to crystalline state by one input light;

when input light is in a TM polarization state, the light input into the two branch waveguides realizes low-loss transmission at an output port 1 and cutoff at an output port 2;

when the input light is in a TE polarization state, the light input into the two branch waveguides realizes low-loss transmission at the output 2 port and cutoff at the output 1 port.

Technical Field

The invention relates to an optical application device, belongs to the technical field of all-optical devices and information processing, and particularly relates to a Y-branch waveguide structure polarization beam splitter based on phase-change material regulation.

Background

In recent years, due to the rapid development of silicon-based integrated optical waveguide devices, optical modulation devices and information processing technologies using light waves as carriers are gradually improved, and on-chip large-capacity optical interconnection and multichannel information processing technologies are important components for developing silicon-based integrated devices. The polarization state is an important attribute of the optical wave, but the two polarization states of TE/TM due to the birefringence effect will adversely affect the transmission of the optical wave. In order to meet the requirement of high-performance transmission of a specific polarization mode, a common polarization modulator realizes separation of two polarization states of TE and TM based on phase regulation. However, for a common polarizer, which is mainly a transmission medium of a silicon (Si) and lithium niobate (LiNbO3) waveguide, there are disadvantages of large size, complex phase control process and small refractive index difference, which are not favorable for ultra-compact and high-performance development of devices.

Phase Change Material (PCM) integrated silicon waveguide polarization modulators are considered to be the most promising modulator, with key materials including SiO₂The substrate, the Si waveguide and the phase change material film. The principle is that the evanescent field coupling effect in the optical waveguide is utilized to enable the phase-change material film to be converted between a crystalline state and an amorphous state, and the polarization mode in the branch is adjusted by different structures and sizes to realize the output of a specific mode (TE/TM). Currently, the introduction of phase change materials is mainly used to modulate the effective refractive index of a mode in a waveguide. When the phase change material film is attached to the top end of the waveguide and is in a crystalline state, the effect of keeping low-loss transmission on input light of a TM mode and stopping the TE mode can be achieved; when the phase change material film is attached to the left side and the right side of the waveguide and is in a crystalline state, the effect of keeping low-loss transmission on input light of a TE mode and stopping a TM mode can be achieved.

However, the current phase-change polarizer design can only realize the selection of one polarization mode (TE/TM), which greatly reduces the application diversity of the polarization selector, and therefore, the multi-channel polarizer based on the phase-change optical modulator becomes the hot spot of the current research. In order to meet the requirement, a multi-channel output Y-branch waveguide structure capable of realizing light beam separation is selected, and a polarization state regulation characteristic can be realized by utilizing a phase change material film, so that a polarization beam splitter of the Y-branch waveguide structure based on phase change material regulation is provided. The position and the size of the phase-change material are adjusted to modulate different polarized light, so that the directional output of two modes is facilitated, and the development of a light polarization modulator and a future optical device is promoted.

Disclosure of Invention

Aiming at the defects and improvement requirements of the existing memory, the invention provides a Y-branch waveguide structure polarization beam splitter based on phase change material regulation and control, and aims to reduce the size of a device and improve the multifunction of the device. In order to solve the technical problems, the invention mainly provides the following technical scheme.

The invention firstly provides a phase change material X for a light polarization modulator_mSb_nTe_k. Preferably, X in the phase change material is a chalcogenide element, and the phase change material thin film is not limited to: ge (germanium) oxide₂Sb₂Te₅、Ge₁Sb₂Te₄、GeTe、Sb₂Te₃、Sc_0.2Sb₂Te₃Such chalcogenide phase change materials.

Further preferably, X ═ Ge, m ═ 2, n ═ 2, and k ═ 5; x is Sc, m is 0.2, n is 2, and k is 3.

Further, the phase-change material film is prepared by adopting a magnetron sputtering method.

Further, the polarization beam splitter of the Y-branch waveguide structure based on the phase change material regulation is characterized in that mode selection is carried out by utilizing the change of effective refractive indexes of a phase change material film and a waveguide; the phase-change optical waveguide comprises a substrate, a Y-branch optical waveguide and a phase-change material film, wherein the Y-branch optical waveguide is arranged on the substrate, a layer of phase-change material film is coated on the upper surface of one branch of the Y-branch optical waveguide, and the branch is marked as an output 1 branch; coating a layer of phase change material film on the left side and the right side of the other branch of the Y-branch optical waveguide respectively, wherein the branch is marked as an output 2 branch; the mode of light in the Y-branch waveguide is modulated.

The Y-branch optical waveguide is divided into three parts, wherein the first part is a Y-shaped total junction section for input, the middle part is a V-shaped structure and forms a Y-shaped structure with the first part, and the third part is an output end which extends out of the tail end of the V-shaped structure and is parallel to the total junction section; the phase change material film on the Y-branch optical waveguide branch is respectively positioned at one end of the output end close to the V-shaped structure. The cross section of the Y-branch optical waveguide is of a rectangular structure.

Preferably, the length of the phase change material film is smaller than the length of the output end, preferably 1000 nm.

Preferably, the width of the phase change material film attached to the upper surface of the output 1 branch is equal to the width of the corresponding output terminal, and the thickness of the phase change material film is selected to be 25 nm.

Preferably, the height of the phase change material film attached to the left and right sides of the output 1 branch is equal to the height of the corresponding output terminal, and the thickness of the phase change material film is selected to be 30 nm.

Preferably, the height, i.e. thickness, of the Y-branch optical waveguide is chosen to be 340nm and the width of each segment is chosen to be 500 nm.

Compared with the prior art, the invention has the beneficial effects

The invention provides a Y-branch waveguide structure polarization beam splitter based on phase change material regulation, when a phase change material film is in a crystalline state, the waveguide section has different effective refractive indexes due to different sizes of the film, low-loss transmission of one mode is ensured by regulating a proper size, and the other mode is cut off, so that the separate output of different modes is realized. The polarization beam splitter based on the phase-change material is beneficial to small-size development of devices, and the non-volatility of the phase-change material is beneficial to low energy consumption of the devices, so that the polarization beam splitter has important application value for future large-scale integration and low energy consumption.

The non-volatile ultrafast phase change polarization beam splitter based on the Si waveguide and the phase change material realizes low loss and miniaturization of devices, has a simple design structure, is convenient to integrate, and lays a foundation for the development of future all-optical devices.

Drawings

FIG. 1 is a schematic structural diagram of a polarization beam splitter with a Y-branch waveguide structure based on phase-change material regulation;

FIG. 2 is a schematic diagram of different TE/TM polarization modes of a designed polarization beam splitter;

FIG. 3 is a schematic diagram of a polarization beam splitter designed to split TM modes;

FIG. 4 is a schematic diagram of a polarization beam splitter designed to split TM modes;

wherein: 1 is substrate, 2 is optical waveguide, and 3 and 4 are phase change material film layers.

Detailed Description

For the purpose of clearly explaining the objects, principles and technical solutions of the present invention, the present invention will be further described with reference to the accompanying drawings and examples. It should be understood that the examples are only for illustrating the invention in further detail, and are not to be construed as limiting the invention, which should not be construed as limiting the scope of the invention.

It should be noted that the illustrations provided in this example are merely illustrative of the basic configuration of the present invention, and the shapes and dimensions may be changed arbitrarily, and the layout of the components may be more complicated.

The invention uses evanescent wave to change the phase-change material from amorphous state to crystalline state, and uses effective refractive index in waveguide to regulate and control the polarization mode, thereby realizing mode separation output.

As shown in fig. 1, a schematic diagram of a polarization beam splitter with a Y-branch waveguide structure based on phase change material modulation includes a substrate 1, an optical waveguide 2, and thin film layers 3 and 4 of phase change material (X ═ Ge, m ═ 2, n ═ 2, k ═ 5; X ═ Sc, m ═ 0.2, n ═ 2, k ═ 3; etc.). Wherein the thickness of the optical waveguide is 340nm and the width is 500 nm. The width of the phase-change material film on the output 1 branch is 500nm, the length is 1000nm, and the thickness is 25nm, and the width of the phase-change material film on the output 2 branch is 30nm, the length is 1000nm, and the thickness is 340 nm.

Example 1

(1) And preparing the Y-branch optical waveguide structure by using electron beam exposure and reactive ion etching, and depositing a phase-change material film by using magnetron sputtering and sputtering window methods.

(2) The transition from the amorphous to the crystalline state is achieved by one input light to the phase state of the phase change material on both branches of the Y waveguide.

(3) The TE/TM polarization mode of the input port in the waveguide was analyzed by simulation.

(4) Through analog analysis of the optical transmission behavior in the Y-branch waveguide, when the input light is in the TM polarization state, the light input into the two-branch waveguide realizes low-loss transmission at the output 1 port, and realizes cutoff at the output 2 port as shown in fig. 3.

(5) When the input light is in the TE polarization state, the light input into the two-branch waveguide realizes low loss transmission at the output 2 port and cutoff at the output 1 port as shown in fig. 4.

(6) Based on the above, the beam splitting of the input TE and TM polarization states is realized, the crystalline state of the phase-change material has a certain modulation effect on the coupling effect of optical signals, and the phase-change material has great application value on-chip multi-level regulation and control.

The above detailed description further illustrates the objects, technical solutions and advantages of the present invention, and the above description is only a specific embodiment of the present invention and is not limited to the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.