Optical fiber and electro-optic modulator having the same

Abstract

The present disclosure relates to the field of optical engineering and optical communication technology, and proposes an optical fiber and an electro-optic modulator having the same. The optical fiber includes an optical fiber body and a covering layer group, and an air hole is provided on the optical fiber body, and the air hole extends along the length direction of the optical fiber body; a covering layer group is provided on the hole wall of the air hole, and the covering layer group includes a first graphene layer, a second graphene layer, and an insulating layer sandwiched between the first graphene layer and the second graphene layer, and the first graphene layer is provided on the hole wall of the air hole. The combination of the optical fiber body, the first graphene layer, the insulating layer and the second graphene layer can realize the regulation of optical signals such as light intensity and light phase in the optical fiber. The modulation has the advantages of simple manufacturing process and convenient integration with the optical fiber communication system, and has broad application prospects in the fields of optical fiber communication, sensors and radar systems.

Description

Technical Field

[0001] The present disclosure relates to the field of optical engineering and optical communication technology, and in particular to an optical fiber and an electro-optic modulator having the same. Background Art

[0002] The electro-optic modulator is an important optoelectronic device that can use control electrical signals to adjust the power, phase, polarization and other characteristics of the transmitted light beam. The working principle of common electro-optic modulators is generally to change the refractive index and absorbance of the crystal by applying voltage, thereby changing the transmission properties of the light beam passing through the crystal to achieve light modulation. It is a key component for high-speed, long-distance optical communications and one of the most important integrated optoelectronic devices. It plays a very important role in coherent optical communication systems, advanced radar systems, fiber optic sensing, laser printing and other fields.

[0003] Optical fiber is a circular waveguide fiber made of glass or plastic, consisting of a high refractive index core and a low refractive index cladding. Light is transmitted in the core by total internal reflection. Optical fiber is widely used in optical fiber communications, medical testing, biosensing and other fields due to its very low cost, very small signal transmission loss and very large signal transmission capacity.

[0004] In the prior art, some optical fibers used in electro-optic modulators may destroy the integrity of the transmission mode due to their own limitations, and some may limit the modulation rate due to the inherent properties of the dielectric insulation layer. Summary of the invention

[0005] A main purpose of the present disclosure is to overcome at least one of the above-mentioned defects of the prior art and to provide an optical fiber and an electro-optic modulator having the same.

[0006] According to a first aspect of the present invention, there is provided an optical fiber, comprising:

[0007] An optical fiber body, wherein an air hole is provided on the optical fiber body and extends along the length direction of the optical fiber body;

[0008] A covering layer group is arranged on the hole wall of the air hole, the covering layer group includes a first graphene layer, a second graphene layer and an insulating layer sandwiched between the first graphene layer and the second graphene layer, and the first graphene layer is arranged on the hole wall of the air hole.

[0009] In one embodiment of the present invention, there is one air hole, and a covering layer group is disposed on the hole wall of the air hole.

[0010] In one embodiment of the present invention, there are a plurality of air holes, and a covering layer group is disposed on the hole wall of at least one of the plurality of air holes.

[0011] In one embodiment of the present invention, a covering layer group is disposed on the hole walls of the plurality of air holes.

[0012] In one embodiment of the present invention, a covering layer set is provided on at least a portion of the outer surface of the optical fiber body;

[0013] The first graphene layer on the outer surface of the optical fiber body is electrically connected to the first graphene layer on the hole wall of the air hole, and the second graphene layer on the outer surface of the optical fiber body is electrically connected to the second graphene layer on the hole wall of the air hole.

[0014] In one embodiment of the present invention, the optical fiber body includes a cladding and a core, and the core is located inside the cladding;

[0015] The air hole is arranged on the cladding, and / or the fiber core is an air hole.

[0016] In one embodiment of the present invention, the insulating layer is a boron nitride layer, a hafnium oxide layer, an aluminum oxide layer or a silicon oxide layer.

[0017] In one embodiment of the present invention, the optical fiber body is a photonic crystal fiber or a hollow core fiber.

[0018] According to a second aspect of the present invention, there is provided an electro-optical modulator comprising the above-mentioned optical fiber.

[0019] In one embodiment of the present invention, the electro-optic modulator further comprises:

[0020] A voltage source, one end of the voltage source is electrically connected to the first graphene layer, and the other end of the voltage source is electrically connected to the second graphene layer.

[0021] The optical fiber of the present invention is composed of an optical fiber body and a covering layer group arranged in the air hole of the optical fiber body, wherein the first graphene layer, the insulating layer and the second graphene layer of the covering layer group are sequentially covered from the hole wall of the air hole outward, that is, the first graphene layer is covered on the hole wall of the air hole, the insulating layer is covered on the side of the first graphene layer away from the hole wall of the air hole, and finally the second graphene layer is covered on the side of the insulating layer away from the first graphene layer. The combination of the optical fiber body, the first graphene layer, the insulating layer and the second graphene layer of the optical fiber modulator can realize the regulation of optical signals such as light intensity and light phase in the optical fiber. The electro-optic modulator prepared by the optical fiber of the present invention has the characteristics of novel materials, small size, convenient coupling with the optical fiber optical path system, and is conducive to optical integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various objects, features and advantages of the present disclosure will become more apparent by considering the following detailed description of preferred embodiments of the present disclosure in conjunction with the accompanying drawings. The accompanying drawings are merely exemplary illustrations of the present disclosure and are not necessarily drawn to scale. In the accompanying drawings, the same reference numerals always refer to the same or similar parts. Among them:

[0023] Figure 1 is a schematic structural diagram of a first viewing angle of an optical fiber according to an exemplary embodiment;

[0024] Figure 2 is a schematic structural diagram of an optical fiber from a second viewing angle according to an exemplary embodiment;

[0025] Figure 3 is a schematic diagram of a local enlarged structure of an optical fiber according to an exemplary embodiment;

[0026] Figure 4 is a schematic diagram showing the operation of an electro-optic modulator according to an exemplary embodiment.

[0027] The following are the descriptions of the reference numerals:

[0028] 10. Optical fiber body; 11. Air hole; 12. Cladding; 13. Fiber core; 20. Covering layer group; 21. First graphene layer; 22. Second graphene layer; 23. Insulating layer; 30. Voltage source. DETAILED DESCRIPTION

[0029] Typical embodiments that embody the features and advantages of the present disclosure will be described in detail in the following description. It should be understood that the present disclosure can have various changes in different embodiments without departing from the scope of the present disclosure, and the descriptions and drawings therein are essentially for illustrative purposes rather than for limiting the present disclosure.

[0030] In the following description of different exemplary embodiments of the present disclosure, reference is made to the accompanying drawings, which form a part of the present disclosure and in which different exemplary structures, systems and steps that can implement multiple aspects of the present disclosure are shown by way of example. It should be understood that other specific schemes of components, structures, exemplary devices, systems and steps can be used, and structural and functional modifications can be made without departing from the scope of the present disclosure. Moreover, although the terms "above", "between", "within", etc. may be used in this specification to describe different exemplary features and elements of the present disclosure, these terms are used herein only for convenience, such as according to the direction of the examples in the accompanying drawings. Nothing in this specification should be construed as requiring a specific three-dimensional orientation of the structure to fall within the scope of the present disclosure.

[0031] An embodiment of the present invention provides an optical fiber, please refer to Figures 1 to 3The optical fiber includes: an optical fiber body 10, on which an air hole 11 is arranged, and the air hole 11 extends along the length direction of the optical fiber body 10; a covering layer group 20, on the hole wall of the air hole 11, a covering layer group 20 is arranged, and the covering layer group 20 includes a first graphene layer 21, a second graphene layer 22 and an insulating layer 23 sandwiched between the first graphene layer 21 and the second graphene layer 22, and the first graphene layer 21 is arranged on the hole wall of the air hole 11.

[0032] An optical fiber according to an embodiment of the present invention is composed of an optical fiber body 10 and a covering layer group 20 disposed in an air hole 11 of the optical fiber body 10, wherein the first graphene layer 21, the insulating layer 23 and the second graphene layer 22 of the covering layer group 20 are sequentially covered from the hole wall of the air hole 11 outward, that is, the first graphene layer 21 is covered on the hole wall of the air hole 11, the insulating layer 23 is covered on the side of the first graphene layer 21 away from the hole wall of the air hole 11, and finally the second graphene layer 22 is covered on the side of the insulating layer 23 away from the first graphene layer 21. The combination of the optical fiber body 10, the first graphene layer 21, the insulating layer 23 and the second graphene layer 22 can realize the adjustment of optical signals such as light intensity and light phase in the optical fiber.

[0033] In one embodiment, the insulating layer 23 is used to isolate the first graphene layer 21 and the second graphene layer 22 to prevent them from being electrically connected.

[0034] Graphene refers to a low-dimensional material in which electrons can move freely in only two dimensions (the size of a certain dimension, such as thickness, is in the range of 1 nanometer to 100 nanometers). Two-dimensional materials exhibit many unique optical, electrical and optoelectronic properties due to their very thin thickness, which restricts the movement of electrons. Graphene is a typical representative of these. Graphene has a constant absorbance (≈2.3%) over a wide spectral range. Due to the Pauli exclusion principle, if the incident photon energy is less than 2 times the change in the Fermi level, the photon cannot be absorbed, and the electrons in the valence band cannot be excited to the conduction band. At this time, graphene becomes transparent, that is, the transmittance theoretically becomes 100%. On the contrary, if the valence band electrons are not excited to the conduction band, or the incident light photon energy is greater than 2 times the change in the Fermi level, the photon can still be absorbed, and the graphene absorbance is still about 2.3%. Therefore, the Fermi level and carrier concentration of graphene can be changed by voltage modulation, thereby changing its transmittance. That is, by disposing the first graphene layer 21 and the second graphene layer 22 on the optical fiber body 10, the light transmittance of the optical fiber can be adjusted by applying a voltage.

[0035] In one embodiment, graphene can be combined with the optical fiber body 10 to develop new optical fiber devices. For example, graphene covered on the surface of side-thrown optical fiber (or D-type optical fiber) can be made into an optical fiber polarizer, and graphene covered on the surface of tapered optical fiber can be used for pulsed optical fiber lasers, etc.

[0036] In one embodiment of the optical fiber body 10, there is one air hole 11, and a covering layer group 20 is disposed on the hole wall of the air hole 11. The optical fiber with one air hole 11 is a single-hole optical fiber, and the covering layer group 20 in the air hole 11 is an annular layer extending from one end of the air hole 11 to the other end, wherein the air hole 11 may be completely covered with the covering layer group 20, and of course, the covering layer group 20 may also be partially present.

[0037] For an embodiment of the optical fiber body 10, as Figure 1 and Figure 2 As shown, there are multiple air holes 11, and a covering layer group 20 is provided on the hole wall of at least one of the multiple air holes 11. The optical fiber with multiple air holes 11 is a holey optical fiber, and the multiple air holes 11 may partially have the covering layer group 20, or all the air holes 11 may be covered with the covering layer group 20. Among them, the covering layer group 20 in the air hole 11 is an annular layer, which extends from one end of the air hole 11 to the other end. The air hole 11 may be completely covered with the covering layer group 20, and of course, the covering layer group 20 may also be partially provided.

[0038] In one embodiment, there are two or more air holes 11. A holey optical fiber refers to a holey optical fiber whose cladding or core is formed by air hole defects.

[0039] In one embodiment, a cover layer group 20 is disposed on the hole walls of the plurality of air holes 11; wherein each first graphene layer 21 on the hole walls of the plurality of air holes 11 is electrically connected, and each second graphene layer 22 on the hole walls of the plurality of air holes 11 is electrically connected. Considering the convenience of applying voltage to the first graphene layer 21 and the second graphene layer 22 in the subsequent process, all the first graphene layers 21 are electrically connected, and all the second graphene layers 22 are electrically connected.

[0040] In one embodiment, a covering layer group 20 is provided on at least part of the outer surface of the optical fiber body 10; wherein the first graphene layer 21 on the outer surface of the optical fiber body 10 is electrically connected to the first graphene layer 21 on the hole wall of the air hole 11, and the second graphene layer 22 on the outer surface of the optical fiber body 10 is electrically connected to the second graphene layer 22 on the hole wall of the air hole 11. The covering layer group 20 on the outer surface of the optical fiber body 10 can be connected to the covering layer group 20 on the hole wall of the air hole 11, that is, all the first graphene layers 21 are electrically connected, all the second graphene layers 22 are electrically connected, and the insulating layer 23 between the first graphene layer 21 and the second graphene layer 22 are all connected.

[0041] In one embodiment, the outer surface of the optical fiber body 10 includes two end faces and a circumferential outer surface located between the two end faces, wherein both the two end faces and the circumferential outer surface may have a covering layer group 20. Of course, the covering layer group 20 may also be partially provided, but it is necessary to ensure that all the covering layer groups 20 can achieve electrical connection of all the first graphene layers 21 and electrical connection of all the second graphene layers 22.

[0042] In one embodiment, when specifically covering the cover layer group 20, the first graphene layer 21 is first covered on the hole wall of the air hole 11 and the outer surface of the optical fiber body 10, and then the insulating layer 23 is covered on the first graphene layer 21, and finally the second graphene layer 22 is covered on the insulating layer 23. When specifically covering, the first graphene layer 21, the insulating layer 23 and the second graphene layer 22 are all a whole. Later, they can be locally processed, that is, part of the cover layer group 20 can be removed.

[0043] In one embodiment, the optical fiber body 10 is a cylinder, the air hole 11 is a circular hole, and a plurality of circular holes are distributed on the cylinder at intervals.

[0044] like Figure 3 As shown, the optical fiber body 10 includes a cladding 12 and a core 13, wherein the core 13 is located inside the cladding 12; wherein the air hole 11 is arranged on the cladding 12, and / or the core 13 is an air hole 11. wherein the core 13 can be an air hole 11, or can be made of a solid material.

[0045] In one embodiment, the optical fiber body 10 has a cladding 12 with a circular cross-section and a core 13 located in the cladding 12, wherein the circular cladding 12 is composed of periodically arranged air holes, and the core 13 can be composed of solid material or one air hole 11. Of course, the cladding 12 can also be completely solid material, that is, without air holes 11, in which case the core 13 is composed of one air hole 11.

[0046] In one embodiment, the insulating layer 23 is made of an insulating material, preferably a boron nitride layer, a hafnium oxide layer, an aluminum oxide layer or a silicon oxide layer.

[0047] In one embodiment, the insulating layer 23 is hexagonal boron nitride (h-BN). Since hexagonal boron nitride (h-BN) is a two-dimensional insulating material, the three-layer structure of graphene-hexagonal boron nitride-graphene can form a parallel plate capacitor structure, and then the carrier concentration and Fermi level position of graphene can be adjusted efficiently and quickly through voltage, thereby regulating the light transmittance of graphene. Therefore, a new type of optical fiber electro-optic modulator can be made by sequentially covering the inner wall of the air hole of the porous optical fiber with graphene-hexagonal boron nitride-graphene layers, which has the advantages of small size, simple structure, preparation process, stable operation, strong anti-interference ability, fast modulation speed, large applicable bandwidth and easy integration with optical fiber optical path, etc., and has important potential application value in the fields of optical fiber communication, radar detection and optical fiber sensing and other optoelectronic devices.

[0048] In one embodiment, the optical fiber body 10 is a photonic crystal fiber. Photonic crystal fiber is a special optical fiber whose cladding is composed of periodically arranged air holes, so it is also called a holey fiber or a microstructured fiber. Photonic crystal fiber can achieve various unique properties that traditional optical fibers do not have by designing waveguide parameters such as the size of the air holes or the hole spacing, such as single-mode transmission in a wide wavelength range and very high mode birefringence. In addition, these periodically arranged small holes also provide space for the integration of various functional materials and optical fibers and the production of all-optical devices.

[0049] In one embodiment, the optical fiber body 10 is a solid photonic crystal fiber.

[0050] In one embodiment, the optical fiber body 10 is a hollow-core photonic crystal fiber.

[0051] In one embodiment, the optical fiber body 10 is a hollow core optical fiber.

[0052] An embodiment of the present invention further provides an electro-optic modulator, please refer to Figure 4 , including the above-mentioned optical fiber.

[0053] like Figure 4 As shown, the electro-optic modulator further includes: a voltage source 30, one end of the voltage source 30 is electrically connected to the first graphene layer 21, and the other end of the voltage source 30 is electrically connected to the second graphene layer 22. The intensity of the output modulator light beam can be adjusted by changing the voltage.

[0054] In one embodiment, two layers of graphene (the first graphene layer 21 and the second graphene layer 22) are connected to two electrode leads respectively, and the two electrode leads are connected to a voltage source 30. The signal beam passes through the optical fiber and interacts with the graphene on the inner wall of the air hole 11. The modulation effect is achieved by adjusting the voltage to change the light intensity of the outgoing beam (modulated light). Figure 4 As shown, the arrow on the left represents the signal light entering the optical fiber, and the arrow on the right represents the modulated light coming out of the optical fiber.

[0055] The electro-optic modulator of the present invention is a graphene-based porous fiber electro-optic modulator. The inner wall of the air hole 11 of the optical fiber body 10 is covered with graphene, hexagonal boron nitride and graphene film in sequence, and two layers of graphene film (the first graphene layer 21 and the second graphene layer 22) are connected to a power source (voltage source 30) by wires, and the graphene Fermi level is changed by adjusting the voltage to adjust the transmittance of light in the graphene optical fiber, and finally electro-optic modulation is achieved.

[0056] The electro-optic modulator of the present invention adopts graphene photonic crystal fiber and graphene-hexagonal boron nitride-graphene structure technology, and has higher modulation speed, modulation efficiency and device integration compared with other similar graphene electro-optic modulators. It has the advantages of wide working frequency band, high modulation depth, low energy loss, simple manufacturing process, convenient integration with optical fiber communication system, etc., and has broad application prospects in the fields of optical fiber communication, sensor and radar system.

[0057] The electro-optic modulator of the present invention has the characteristics of novel materials, small size, convenient coupling with optical fiber optical path system, and is conducive to optical integration. It can be widely used in optical fiber communication, sensors, lasers, optical integration systems and all-optical communications.

[0058] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and example embodiments are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0059] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An optical fiber, characterized in that: include: An optical fiber body (10), wherein the optical fiber body (10) is provided with an air hole (11), and the air hole (11) extends along the length direction of the optical fiber body (10); A covering layer group (20), the covering layer group (20) being arranged on the hole wall of the air hole (11), the covering layer group (20) comprising a first graphene layer (21), a second graphene layer (22), and an insulating layer (23) sandwiched between the first graphene layer (21) and the second graphene layer (22), the first graphene layer (21) being arranged on the hole wall of the air hole (11); The optical fiber body (10) comprises a cladding (12) and a core (13), wherein the core (13) is located inside the cladding (12); wherein the air hole (11) is arranged on the cladding (12), and / or the core (13) is the air hole (11); and the covering layer group (20) is arranged on at least a portion of the outer surface of the optical fiber body (10); The first graphene layer (21) on the outer surface of the optical fiber body (10) is electrically connected to the first graphene layer (21) on the hole wall of the air hole (11), and the second graphene layer (22) on the outer surface of the optical fiber body (10) is electrically connected to the second graphene layer (22) on the hole wall of the air hole (11).

2. The optical fiber according to claim 1, characterized in that There is one air hole (11), and the covering layer group (20) is provided on the hole wall of each air hole (11).

3. The optical fiber according to claim 1, characterized in that There are a plurality of air holes (11), and the covering layer group (20) is provided on the hole wall of at least one of the air holes (11) among the plurality of air holes (11).

4. The optical fiber according to claim 3, characterized in that The covering layer group (20) is arranged on the hole walls of the plurality of air holes (11); Wherein, each of the first graphene layers (21) on the hole walls of the plurality of air holes (11) is electrically connected, and each of the second graphene layers (22) on the hole walls of the plurality of air holes (11) is electrically connected.

5. The optical fiber according to claim 1, characterized in that The insulating layer (23) is a boron nitride layer, a hafnium oxide layer, an aluminum oxide layer or a silicon oxide layer.

6. The optical fiber according to claim 1, characterized in that The optical fiber body (10) is a photonic crystal optical fiber or a hollow core optical fiber.

7. An electro-optic modulator, characterized in that: An optical fiber comprising the optical fiber according to any one of claims 1 to 6.

8. The electro-optic modulator according to claim 7, characterized in that: The electro-optic modulator further comprises: A voltage source (30), one end of the voltage source (30) being electrically connected to the first graphene layer (21), and the other end of the voltage source (30) being electrically connected to the second graphene layer (22).

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