CN111240048A

CN111240048A - Optical modulator

Info

Publication number: CN111240048A
Application number: CN202010115216.8A
Authority: CN
Inventors: 刘江涛; 蔡勋明; 周朝彪; 范梦慧; 徐艳丽; 吴媛媛
Original assignee: Guizhou Minzu University
Current assignee: Guizhou Minzu University
Priority date: 2020-02-25
Filing date: 2020-02-25
Publication date: 2020-06-05
Anticipated expiration: 2040-02-25
Also published as: CN111240048B

Abstract

The invention discloses an optical modulator which comprises a conductive bottom layer, wherein insulating layers are fixedly arranged at two ends of the upper surface of the conductive bottom layer, a lubricating layer is fixedly arranged on the upper surface of each insulating layer, the lower surfaces of two ends of a two-dimensional material are arranged on the upper surface of each lubricating layer, a first electrode is arranged on the conductive bottom layer, a second electrode is arranged on each lubricating layer, and the two-dimensional material slides on the lubricating layers. The invention has the beneficial effects that: thereby adjust the electrostatic force between two-dimensional material and the base through changing the voltage between two-dimensional material and the electrically conductive bottom for two-dimensional material slides on the lubricant film, thereby adjust the distance between two-dimensional material and the electrically conductive base and realize light regulation and control, and this kind of electro-optical modulator can realize the modulation when ultraviolet reaches infrared spectrum within range, and modulation speed is fast, and modulation voltage is little, the low power dissipation.

Description

Optical modulator

Technical Field

The invention relates to the technical field of electro-optics, in particular to an optical modulator.

Background

Optical modulators have a wide range of applications in optical communications, and may also be used in radar and laser modulation. Light modulation is made by mechanical modulation, acousto-optic modulation, magneto-optic modulator, electro-optic modulation, and electro-absorption modulation. The electro-optical modulation is modulated by electro-optical effect such as linear electro-optical effect (pockels effect), etc., and the speed is very high, but the electro-optical modulation can only work near a specific wavelength usually, and the modulation wavelength range is narrow. Two-dimensional materials such as graphene and the like have also been used to fabricate electro-optic modulators. Which primarily modulates the light absorption between the energy bands by modulating the fermi level of the two-dimensional material. The adjustment frequency is also high. However, such modulators can only operate in the band where the photon transition energy is near the fermi level. The wavelength range of the mechanical light modulation such as chopper modulation is extremely wide, and light beams from ultraviolet to far infrared bands can be simultaneously regulated, but the modulation speed of the traditional mechanical light modulation is low, the maximum modulation frequency is only dozens of kilohertz, and the mechanical light modulation is not suitable for modern high-speed optical communication and cannot be applied to the fields of ultrahigh-speed display, imaging and the like.

Disclosure of Invention

The technical problem to be solved by the invention is to provide an optical modulator, wherein the two-dimensional material slides on a lubricating layer by utilizing electrostatic force through changing the voltage between the two-dimensional material and a conductive bottom layer, and the distance between the two-dimensional material and a conductive base is adjusted so as to realize optical regulation and control.

The technical scheme for solving the technical problems is as follows: including electrically conductive bottom, the fixed insulating layer that is equipped with on the both ends of the upper surface of electrically conductive bottom, the last fixed surface of insulating layer is equipped with the lubricant film, the lower surface at two-dimensional material's both ends is established on the upper surface of lubricant film, be equipped with first electrode on the electrically conductive bottom, be equipped with the second electrode on the lubricant film, two-dimensional material is in slide on the lubricant film.

The invention has the beneficial effects that: because the two-dimensional material can slide on the lubricating layer, when applying certain voltage between electrically conductive bottom and the two-dimensional material, because the effect of electrostatic force, attract each other or repel between electrically conductive bottom and the two-dimensional material to make the two-dimensional material slide on the lubricating layer and change the interval between electrically conductive bottom and the two-dimensional material, because the interference of light between electrically conductive bottom and two-dimensional material, can effectual regulation and control the light absorption and the light reflection of electrically conductive bottom and two-dimensional material, thereby realize the high-efficient modulation of light. When the size of the electromechanical system is reduced to the micron or nanometer size, the movement speed is rapidly improved, and the modulation speed can reach above GHz. Compared with the traditional micro-nano structure, the two-dimensional material is thinnest, the mass of the unit area is smaller, the acceleration is faster, and the modulation speed is higher.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the two-dimensional material is single-layer or multi-layer graphene.

The beneficial effects of adopting above-mentioned further scheme are that graphite alkene unit area mass density is low, and modulation speed is high, and in addition, graphite alkene is in ultraviolet to infrared band absorptivity unanimous basically, and the working band is wide.

Furthermore, the lubricating layer is made of graphite.

The further scheme has the advantages that the super-lubricating effect exists between the graphite cleavage plane and the graphene, the friction coefficient is extremely low, the modulation speed of modulation is favorably improved, and the power consumption is reduced.

Furthermore, the surface of the bulge in the middle of the conductive bottom layer is made of smooth aluminum.

The beneficial effect of adopting above-mentioned further scheme is that the aluminium material all has higher reflectivity in ultraviolet to infrared band, is favorable to improving the light interference between base and the two-dimensional material, improves modulation efficiency and work bandwidth.

On the basis of the scheme, the invention can be further improved as follows.

Further, the lubricating layer is an L-shaped lubricating layer.

The beneficial effect of adopting the above further scheme is that after voltage is applied, the two-dimensional material slides on the lubricating layer, the contact area is reduced, the surface binding energy between the two-dimensional material and the lubricating layer is reduced, and the restoring force is provided, so that the sliding of the two-dimensional material on the lubricating layer is weakened or prevented. The restoring force is proportional to the change in contact area. The L-shaped lubricating layer, which is narrow at the top and wide at the bottom, advantageously provides a smaller restoring force during the initial phase, i.e. when the distance between the two-dimensional material and the base is larger, which is advantageous for increasing the modulation speed. And provides a greater restoring force when the two-dimensional material is at a small distance from the base, which is advantageous in preventing the two-dimensional material from sticking to the base, so that the modulation fails. In addition, the friction force is in direct proportion to the total contact area in the structure, the lubrication layer with the narrow top and the wide bottom, namely the L-shaped lubrication layer, can adjust the friction force under the condition that the restoring force is not changed, the phenomenon that the friction force is too large to cause too large power consumption and low modulation rate is avoided, and the phenomenon that the two-dimensional material vibrates due to too small friction force can also be avoided.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of a lubricating layer;

FIG. 3 is a graph of light modulation rate versus time for light of wavelength 550 nm modulated by a square wave voltage with a period of 15 nm;

FIG. 4 is a graph of modulated light wavelength versus modulation rate;

FIG. 5 is a graph of incident light angle versus adjustment rate;

in the drawings, the components represented by the respective reference numerals are listed below:

1. conductive bottom layer, 2, insulating layer, 3, lubricating layer, 4, two-dimensional material, 5, modulated light, 6, second electrode, 7, first electrode.

Detailed Description

In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the box or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection can be mechanical connection or circuit connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Example 1:

as shown in fig. 1, in this embodiment, an optical modulator includes a conductive bottom layer 1, insulating layers 2 are fixedly disposed at two ends of an upper surface of the conductive bottom layer 1, two lubricating layers 3 are fixedly disposed on upper surfaces of the insulating layers 2, two-dimensional materials 4 are disposed between upper surfaces of the lubricating layers 3, lower surfaces of two ends of the two-dimensional materials 4 are respectively disposed on two upper surfaces of the lubricating layers 3, a first electrode 7 is disposed on the conductive bottom layer 1, a second electrode 6 is disposed on the lubricating layers 3, positive and negative polarities of the first electrode 7 and the second electrode 6 may be opposite or homopolar, different electrodes attract each other, a distance decreases, the same type repels each other, the distance increases, and the middle portion of the two-dimensional materials 4 and the conductive bottom layer 1 are separated by air or vacuum.

The lubricating layer 3 is an L-shaped lubricating layer, two L-shaped lubricating layers are respectively arranged on the lower surfaces of two ends of the two-dimensional material 4, and the two L-shaped lubricating layers are horizontally arranged oppositely, as shown in fig. 2. When the voltage is applied to the L-shaped lubricating layer, the two-dimensional material 4 slides on the lubricating layer 3, the contact area is reduced, and the surface binding energy between the two-dimensional material 4 and the lubricating layer 3 is reduced, so that a restoring force is provided, and the sliding of the two-dimensional material 4 on the lubricating layer 3 is weakened or prevented. The restoring force is in direct proportion to the change of the contact area, and the L-shaped lubricating layer is adopted, so that the change of the contact area is small during sliding due to the fact that the upper portion of the L is thin, and the restoring force is reduced, and therefore the modulation voltage is reduced. Meanwhile, when the sliding length is too large, the two-dimensional material 4 reaches the bottom edge of the L shape, if the sliding is continued, the contact area is greatly changed, and a great restoring force is caused, so that the continuous sliding of the two-dimensional material 4 is prevented, the separation of the two-dimensional material 4 from the lubricating layer 3 is avoided, the two-dimensional material 4 is in direct contact with the conductive bottom layer 1, and the two-dimensional material 4 is better supported.

The distance between the graphite dissociation surface lubricating layers 2 at the two sides, namely the width of the gap is 40 microns, the material of the lubricating layer 3 is graphite, the surface is a dissociation surface, and the width is 1 micron; when no voltage is applied, the distance between the graphene and the conductive bottom layer 1 is 110 nanometers, the length and the width of the conductive bottom layer are both 35 micrometers, the working voltage is 0.18V, and the conductive bottom layer 1 is made of smooth aluminum material.

Because the two-dimensional material 4 can slide on the lubricating layer 3, when exerting certain voltage between electrically conductive bottom 1 and two-dimensional material 4, attract each other between electrically conductive bottom 1 and the two-dimensional material 4 to can change the interval between electrically conductive bottom 1 and the two-dimensional material 4, because the interference of light between electrically conductive bottom 1 and two-dimensional material 4, can the light absorption and the light reflection of effectual regulation and control electrically conductive bottom 1 and two-dimensional material 4, thereby realize the high-efficient modulation of light.

The specific modulation effect is shown in fig. 3, 4 and 5, and the light beams with wave bands of the whole visible light, near infrared and communication wave bands can be simultaneously regulated and controlled, the wavelength range is more than 1.2 micrometers, and the wavelength range is 2-3 orders of magnitude larger than the working wavelength range of the traditional photoelectric modulation; the working voltage is only 0.18V, which is about 1-2 orders of magnitude smaller than that of the traditional light modulation; the modulation response speed is about 2 nanoseconds, the modulation frequency is above 100MHz, and the modulation speed is 2-4 orders of magnitude faster than the traditional mechanical modulation speed.

The angle of incidence of the modulated light 4 is preferably adjusted to be 15-80 degrees oblique to the modulated light 5. When the light enters obliquely, the light absorption adjustable range of the graphene is larger, and the reflection change is larger.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical modulator, characterized by: including electrically conductive bottom layer (1), the fixed insulating layer (2) that is equipped with on the both ends of the upper surface of electrically conductive bottom layer (1), the last fixed surface of insulating layer (2) is equipped with lubricating layer (3), the lower surface at the both ends of two-dimensional material (4) is established on the upper surface of lubricating layer (3), be equipped with first electrode (7) on electrically conductive bottom layer (1), be equipped with second electrode (6) on lubricating layer (3), two-dimensional material (4) are in sliding on lubricating layer (3).

2. A light modulator according to claim 1 wherein: the two-dimensional material (4) is single-layer or multi-layer graphene.

3. A light modulator according to claim 2 wherein: the lubricating layer (3) is made of graphite.

4. A light modulator according to any one of claims 1-3 wherein: the surface of the bulge in the middle of the conductive bottom layer (1) is made of smooth aluminum.

5. A light modulator according to any one of claims 1-3 wherein: the lubricating layer (3) is an L-shaped lubricating layer.