CN111240048B - Optical modulator - Google Patents

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

a light modulator

technical field

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

Background technique

Optical modulators have a wide range of applications in optical communications and can also be used in radar and laser modulation. Optical modulation includes mechanical modulation, acousto-optic modulation, magneto-optic modulator, electro-optic modulation, and electro-absorption modulation. Among them, electro-optic modulation uses electro-optic effects such as linear electro-optic effect (Pockels effect) to modulate, and its speed is extremely high, but usually it can only work near a specific wavelength, and the modulation wavelength range is narrow. Two-dimensional materials such as graphene have also been used to make electro-optic modulators. It mainly modulates the interband light absorption by modulating the Fermi level of two-dimensional materials. The adjustment frequency is also high. But this modulator can only work in the band where the photon transition energy is near the Fermi level. Mechanical light modulation, such as a chopper, has a very wide modulation wavelength range, and can simultaneously regulate the beams in the ultraviolet to far-infrared bands. However, the modulation speed of traditional mechanical light modulation is low, and its maximum modulation frequency is only tens of kilohertz, which is not suitable for Modern high-speed optical communication cannot be applied to fields such as ultra-high-speed display and imaging.

Contents of the invention

The technical problem to be solved by the present invention is to provide an optical modulator, by changing the voltage between the two-dimensional material and the conductive bottom layer, thereby using the electrostatic force to make the two-dimensional material slip on the lubricating layer, and adjust the two-dimensional material and the conductive base The distance between them can realize light control. This kind of micro-nano mechanical electro-optic modulator can realize simultaneous modulation in the ultraviolet to infrared spectral range, and the modulation speed is fast, the modulation voltage is small, and the power consumption is low.

The technical solution of the present invention to solve the above-mentioned technical problems is as follows: comprising a conductive bottom layer, an insulating layer is fixedly arranged on both ends of the upper surface of the conductive bottom layer, a lubricating layer is fixedly arranged on the upper surface of the insulating layer, and the two-dimensional material The lower surfaces of both ends of the two ends are arranged on the upper surface of the lubricating layer, the first electrode is arranged on the conductive bottom layer, the second electrode is arranged on the lubricating layer, and the two-dimensional material slides on the lubricating layer .

The beneficial effect of the present invention is: because the two-dimensional material can slide on the lubricating layer, when a certain voltage is applied between the conductive bottom layer and the two-dimensional material, due to the electrostatic force, the conductive bottom layer and the two-dimensional material are attracted or repelled each other , so that the two-dimensional material slips on the lubricating layer and changes the distance between the conductive bottom layer and the two-dimensional material. Due to the interference of light between the conductive bottom layer and the two-dimensional material, the distance between the conductive bottom layer and the two-dimensional material can be effectively adjusted. Light absorption and light reflection, resulting in efficient modulation of light. And when the size of the electromechanical system is reduced to a micron or nanometer size, its motion speed increases rapidly, and the modulation speed can reach above GHz. Compared with traditional micro-nano structures, two-dimensional materials are the thinnest, with smaller mass per unit area, faster acceleration and higher modulation speed.

On the basis of the above technical solutions, the present invention can also be improved as follows.

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

The beneficial effect of adopting the above further solution is that the mass density per unit area of graphene is low, and the modulation speed is high. In addition, the absorption rate of graphene in the ultraviolet to infrared band is basically the same, and the working band is wide.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, the lubricating layer is made of graphite.

The beneficial effect of adopting the above further solution is that there is a super-lubricating effect between the graphite cleavage surface and the graphene, and the friction coefficient is extremely small, which is conducive to improving the modulation speed of modulation and reducing power consumption.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, the raised surface in the middle of the conductive bottom layer is made of smooth aluminum.

The beneficial effect of adopting the above further scheme is that the aluminum material has high reflectivity in the ultraviolet to infrared band, which is beneficial to improve the optical interference between the base and the two-dimensional material, and improve the modulation efficiency and working bandwidth.

On the basis of the above solution, the present invention can also be improved as follows.

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

The beneficial effect of adopting the above-mentioned further scheme is that when a voltage is applied, the two-dimensional material slips on the lubricating layer, the contact area decreases, and the surface binding energy between the two-dimensional material and the lubricating layer decreases, which will provide a restoring force, Weaken or prevent the sliding of two-dimensional materials on the lubricating layer. 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, is conducive to providing a small restoring force in the initial stage, that is, when the distance between the two-dimensional material and the base is large, which is conducive to improving the modulation speed. And when the distance between the two-dimensional material and the base is small, a large restoring force is provided, which is beneficial to avoid the adhesion between the two-dimensional material and the base, so that the modulation fails. In addition, in this structure, the friction force is proportional to the total contact area, and the L-shaped lubricating layer, which is narrow at the top and wide at the bottom, can adjust the friction force without changing the restoring force, so as to avoid excessive friction force so that the work Excessive consumption and low modulation rate can also avoid the vibration phenomenon of two-dimensional materials caused by too small friction force.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the structural representation of lubricating layer;

Fig. 3 is a graph showing the relationship between the light modulation rate and time of light with a wavelength of 550 nanometers modulated by a square wave voltage with a period of 15 nanometers;

Fig. 4 is a graph of the relationship between the wavelength of modulated light and the modulation rate;

Figure 5 is a diagram of the relationship between the incident light angle and the adjustment rate;

In the accompanying drawings, the list of parts represented by each label is as follows:

1. Conductive bottom layer, 2. Insulation layer, 3. Lubricating layer, 4. Two-dimensional material, 5. Modulated light, 6. Second electrode, 7. First electrode.

Detailed ways

In the description of the present invention, it should be noted that the orientation or position indicated by the terms "up", "down", "front", "rear", "left", "right", "inside", "outside" etc. The relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred box or element must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it can be mechanical connection or circuit connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1:

As shown in Figure 1, in this embodiment, an optical modulator includes a conductive bottom layer 1, an insulating layer 2 is fixed on both ends of the upper surface of the conductive bottom layer 1, and two insulating layers 2 The upper surface is fixedly provided with a lubricating layer 3, two-dimensional material 4 is arranged between the upper surfaces of the two described lubricating layers 3, and the lower surfaces of two ends of the two-dimensional material 4 are respectively arranged on two described lubricating layers 3 On the upper surface of the upper surface, the conductive bottom layer 1 is provided with a first electrode 7, and the lubricating layer 3 is provided with a second electrode 6. The positive and negative of the first electrode 7 and the second electrode 6 can be opposite, or can be Electrodes of the same electrode and different electrodes attract each other, and the distance becomes smaller, while the same electrode repels, and the distance increases. The middle part of the two-dimensional material 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 provided on the lower surfaces of the two ends of the two-dimensional material 4, and the two L-shaped lubricating layers are arranged horizontally opposite each other, as shown in FIG. 2 . L-shaped lubricating layer When the voltage is applied, the two-dimensional material 4 slides on the lubricating layer 3, the contact area decreases, and the surface binding energy between the two-dimensional material 4 and the lubricating layer 3 decreases, which will provide a restoring force, Weaken or prevent the sliding of the two-dimensional material 4 on the lubricating layer 3 . The restoring force is proportional to the change of the contact area. The L-shaped lubricating layer is adopted. Since the upper part of the L is thinner, the change of the contact area is small during sliding, which is beneficial to reduce the restoring force and thus reduce the modulation voltage. At the same time, when the sliding length is too large, the two-dimensional material 4 reaches the bottom edge of the L shape. If the sliding continues, the contact area will change greatly, which will lead to a huge restoring force, thereby preventing the two-dimensional material 4 from continuing. Slip, thereby avoiding the detachment of the two-dimensional material 4 from the lubricating layer 3 and direct contact with the conductive bottom layer 1, so as to better support the two-dimensional material 4.

The distance between the lubricating layer 2 of the graphite dissociation surface on both sides 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 graphene and the conductive bottom layer The distance between 1 is 110 nanometers, the length and width of the conductive bottom layer are both 35 microns, the working voltage is 0.18 volts, and the conductive bottom layer 1 is made of smooth aluminum material.

Since the two-dimensional material 4 can slide on the lubricating layer 3, when a certain voltage is applied between the conductive bottom layer 1 and the two-dimensional material 4, the conductive bottom layer 1 and the two-dimensional material 4 attract each other, so that the conductive bottom layer 1 and the two-dimensional material can be changed. Due to the interference of light between the conductive bottom layer 1 and the two-dimensional material 4, the light absorption and light reflection of the conductive bottom layer 1 and the two-dimensional material 4 can be effectively regulated, thereby realizing efficient modulation of light.

The specific modulation effect is shown in Figure 3, Figure 4 and Figure 5. It can simultaneously control the beams of the entire visible light, near-infrared and communication bands. The wavelength range is above 1.2 microns, which is 2-2- 3 orders of magnitude; the working voltage is only 0.18V, which is about 1-2 orders of magnitude smaller than traditional optical modulation; the modulation response speed is about 2 nanoseconds, and the modulation frequency is above 100MHz, which is 2-4 times faster than traditional mechanical modulation order of magnitude.

The incident angle of the adjusted light 4 is preferably adjusted, when the modulated light 5 is incident at an angle of 15-80 degrees. When the incidence is oblique, the adjustable range of graphene's light absorption is larger, and the reflection changes greatly.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention Inside.

Claims (5)

1. An optical modulator, characterized by: including electrically conductive bottom (1), the fixed insulating layer (2) that is equipped with on the both ends of the upper surface of electrically conductive bottom (1), the last fixed surface of insulating layer (2) is equipped with lubricating layer (3), establish the lower surface at the both ends of two-dimensional material (4) on the upper surface of lubricating layer (3), be equipped with first electrode (7) on electrically conductive bottom (1), be equipped with second electrode (6) on lubricating layer (3), two-dimensional material (4) are in slide on lubricating layer (3), work as electrically conductive bottom (1) with when applying certain voltage between two-dimensional material (4), electrically conductive bottom (1) with inter attraction or repulsion between two-dimensional material (4), thereby make two-dimensional material (4) are in slide and change on lubricating layer (3) electrically conductive bottom (1) with interval between two-dimensional material (4), regulation and control electrically conductive bottom (1) with the light absorption and the light reflection of two-dimensional material (4).

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.

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