A method for preparing graphene optical fiber

Abstract

The present invention belongs to the field of graphene optical communication devices, and discloses a method for preparing a graphene optical fiber, wherein a bare optical fiber is pretreated by electron beam optical fiber pretreatment technology, followed by chemical vapor deposition, and a layer of graphene film is deposited on the bare optical fiber by chemical reaction of carbon source gas, thereby obtaining a novel graphene optical fiber. The graphene optical fiber obtained by the present invention has the characteristics of ultra-wide spectral range (850-1600nm), high bandwidth, bending resistance and low loss, and is suitable for high-speed, large-capacity medium and short-distance transmission, meeting the requirements of optical fiber wiring of 5G base stations and data centers.

Description

Technical Field

[0001] The invention relates to the field of graphene optical communication devices, and in particular to a method for preparing a graphene optical fiber. Background Art

[0002] With the development of the Internet, people are entering the era of the Internet of Things. The premise of the interconnection of all things is the popularization of the Internet. At present, the Internet of Things is entering the 5G era. 5G technology has five characteristics: high speed, low power consumption, low latency, massive Internet of Things communication, and ubiquitous network. It provides higher network configuration and faster network transmission. Optical fiber as a transmission medium is the basis of 5G and is used to transmit optical signals. The current communication network is based on the transmission of optical signals. According to the different transmission modes of light in optical fibers, optical fibers can be divided into single-mode optical fibers and multi-mode optical fibers. The so-called single-mode optical fiber can only transmit signal waves of a single wavelength. The optical signal will propagate along a straight line without reflection or dispersion in the middle, resulting in a wide transmission bandwidth of single-mode optical fiber, which is suitable for long-distance transmission of light. In contrast, the so-called multi-mode optical fiber can carry the transmission of multiple optical signals, that is, simultaneously propagate multiple optical signals of different wavelengths in one optical fiber, which will lead to the generation of large inter-modal dispersion, so that its transmission performance is poor, the bandwidth is narrow, and the capacity is small, so it is suitable for medium and short-distance transmission of light. Optical fibers will inevitably bend during the wiring process, which can easily cause loss of optical signals, thereby affecting the optical properties of the optical fiber, such as the cutoff wavelength, high-power injection, and storage life. Therefore, improving the bending performance of 5G optical fibers has always been the focus of attention. Graphene has an ultra-large specific surface area, high hardness, high strength, excellent thermal conductivity, and excellent electrical and optical physical and chemical properties. Combining graphene with optical fibers to form graphene optical fibers will greatly improve the optical properties of optical devices. The graphene optical fiber in the present invention replaces the coating on the surface of the optical fiber with a graphene film, which can play the role of giving the optical fiber anti-bending and reducing the micro-bending loss of the optical fiber with the traditional coating. It can also give an ultra-wide spectral working range, increase the bandwidth under the specified optical spectrum signal, and extend the transmission distance of the optical signal, so as to adapt to various scenarios of 5G applications.

[0003] Regarding the preparation method of graphene optical fiber, the graphene optical fiber can be prepared by chemical vapor deposition (CVD) and coating with graphene coating. "Guo Yiyong. Research on distributed optical fiber rapid temperature measurement system based on graphene optical fiber [D]. Chengdu: Master's thesis of University of Electronic Science and Technology of China, 2022." discloses a method of spraying a layer of graphene coating on the surface of bare optical fiber by spraying, but this method will generate stress in the coating and increase the loss of optical signal in the optical fiber. If the CVD method can be used to grow a graphene film in situ on the optical fiber, the transfer of the graphene film can be avoided. "Wang Gan, Zhou Xingguo. A composite graphene optical fiber cable and preparation method [P]. Chinese patent: CN 105469852A, 2016-01-13." The CVD method is used to prepare graphene optical fiber, and the graphene film deposited on the copper or nickel surface is transferred to the optical fiber surface by acid etching, which will damage the optical fiber surface, thereby affecting the performance of the graphene optical fiber. Electron beam technology is an excellent surface modification technology. With the energy it carries, it can generate a temperature of more than 6000℃ on the surface of the material, which is enough to melt high-melting-point materials such as quartz. When the electron beam is irradiated on the surface of the optical fiber, defects such as nanoscale holes will be generated. The existence of such defects can reduce the nucleation work of carbon atoms, which is conducive to the nucleation of carbon atoms produced by the decomposition of carbon source gas in the subsequent vapor deposition process at the hole defects, and then grow to form graphene islands. As the gas phase reaction proceeds, the various graphene islands are connected to form a complete graphene film, directly preparing graphene optical fibers with excellent optical properties. Summary of the invention

[0004] The graphene optical fiber prepared by the present invention using electron beam optical fiber pretreatment technology and chemical vapor deposition technology has the characteristics of ultra-wide spectral range (850-1600nm), high bandwidth, bending resistance and low loss, which can meet the optical fiber wiring needs of 5G base stations and data centers.

[0005] The technical solution of the present invention is as follows: A method for preparing graphene optical fiber, the specific preparation steps are as follows:

[0006] Step (1), optical fiber pretreatment: the surface of the bare optical fiber is treated with anhydrous ethanol and then dried, placed in a vacuum chamber, and subjected to pulsed electron beam treatment; the pulsed electron beam power is 4-15 kW, the acceleration voltage is 10-27 kV, and the vacuum degree of the electron gun is 7×10 -2 Pa, scanning frequency is 5-10KHz, pulse number is 5-25 times, pulse width is 1-3.5μs, scanning waveform is one of sine wave, square wave, triangle wave, ellipse and circle;

[0007] Step (2), chemical vapor deposition of graphene film: placing the pretreated bare optical fiber into a CVD tube furnace, introducing an inert protective gas and heating to 1000-1500° C., stabilizing the temperature and maintaining it for 20-40 minutes; stopping the introduction of the inert protective gas, introducing a carbon source gas, and reacting for 30-50 minutes until the reaction is complete; turning off the carbon source gas, and then introducing an inert protective gas to exhaust the carbon source gas, and cooling the CVD tube furnace to room temperature under the inert protective gas environment to obtain a graphene optical fiber.

[0008] The pulse electron beam power is 6-12 kW, the acceleration voltage is 18-25 kV, and the vacuum degree of the electron gun is 7×10 -2 Pa, the scanning frequency is 6-8KHz, and the pulse width is 2-3μs.

[0009] The inert protective gas is hydrogen, argon or nitrogen.

[0010] The carbon source gas is methane, carbon monoxide, ethylene, propylene, butene, benzene, acetylene or n-hexane.

[0011] The bandwidth of the graphene optical fiber finally prepared is different in the working windows of 850nm, 953nm, 1300nm and 1550nm. In the working window of 850nm, the bandwidth of the optical fiber is ≥4700MHz﹒km; in the working window of 953nm, the bandwidth of the optical fiber is ≥2470MHz﹒km; in the working window of 1300nm, the bandwidth of the optical fiber is ≥850MHz﹒km; in the working window of 1550nm, the bandwidth of the optical fiber is ≥360MHz﹒km.

[0012] The obtained graphene optical fiber has different optical attenuation coefficients in the working windows of 850nm, 953nm, 1300nm and 1550nm. In the working window of 850nm, the optical attenuation coefficient is ≤2.4dB / km; in the working window of 953nm, the optical attenuation coefficient is ≤1.7dB / km; in the working window of 1300nm, the optical attenuation coefficient is ≤0.6dB / km; in the working window of 1550nm, the optical attenuation coefficient is ≤0.3dB / km.

[0013] The obtained graphene optical fiber can also be applied in sensors, intelligent manufacturing, industrial big data, and aerospace fields.

[0014] Beneficial effects of the invention: The invention proposes a method for preparing graphene optical fiber. The graphene optical fiber prepared based on electron beam optical fiber pretreatment technology and chemical vapor deposition technology has a stable production process and a high yield rate. The obtained product has the characteristics of ultra-wide spectral range (850-1600nm), high bandwidth, bending resistance and low loss, and is suitable for optical fiber wiring of 5G base stations and data centers. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the graphene optical fiber of the present invention.

[0016] Figure 2 The figure shows the change of the effective mode bandwidth of the graphene optical fiber under different spectral conditions in Example 2.

[0017] Figure 3 The variation of the light attenuation coefficient under different spectral conditions in Example 2.

[0018] In the figure: 1-graphene film; 2-cladding; 3-core; 4-optical signal. DETAILED DESCRIPTION

[0019] The features of the present invention are further described below by way of examples:

[0020] A method for preparing a graphene optical fiber, the specific preparation steps are as follows:

[0021] Step (1), optical fiber pretreatment: the surface of the bare optical fiber is treated with anhydrous ethanol and then dried, placed in a vacuum chamber, and subjected to pulsed electron beam treatment; the pulsed electron beam power is 4-15 kW, the acceleration voltage is 10-27 kV, and the vacuum degree of the electron gun is 7×10 -2 Pa, scanning frequency is 5-10KHz, pulse number is 5-25 times, pulse width is 1-3.5μs, scanning waveform is one of sine wave, square wave, triangle wave, ellipse and circle;

[0022] Step (2), chemical vapor deposition of graphene film: placing the pretreated bare optical fiber into a CVD tube furnace, introducing an inert protective gas and heating to 1000-1500° C., stabilizing the temperature and maintaining it for 20-40 minutes; stopping the introduction of the inert protective gas, introducing a carbon source gas, and reacting for 30-50 minutes until the reaction is complete; turning off the carbon source gas, and then introducing an inert protective gas to exhaust the carbon source gas, and cooling the CVD tube furnace to room temperature under the inert protective gas environment to obtain a graphene optical fiber.

[0023] Preferably, a method for preparing a graphene optical fiber, the specific preparation steps are as follows:

[0024] Step (1), optical fiber pretreatment: the surface of the bare optical fiber is treated with anhydrous ethanol and then dried, placed in a vacuum chamber, and subjected to pulsed electron beam treatment; the pulsed electron beam power is 6-12 kW, the acceleration voltage is 18-25 kV, and the vacuum degree of the electron gun is 7×10 -2 Pa, scanning frequency is 6-8KHz, pulse width is 2-3μs, scanning waveform is one of sine wave, square wave, triangle wave, ellipse and circle;

[0025] Step (2), chemical vapor deposition of graphene film: placing the pretreated bare optical fiber into a CVD tube furnace, introducing an inert protective gas and heating to 1000-1500° C., stabilizing the temperature and maintaining it for 20-40 minutes; stopping the introduction of the inert protective gas, introducing a carbon source gas, and reacting for 30-50 minutes until the reaction is complete; turning off the carbon source gas, and then introducing an inert protective gas to exhaust the carbon source gas, and cooling the CVD tube furnace to room temperature under the inert protective gas environment to obtain a graphene optical fiber.

[0026] Embodiment 1:

[0027] The specific preparation steps of the prepared graphene optical fiber are as follows:

[0028] (1) Electron beam fiber pretreatment: The bare optical fiber was pre-wiped with anhydrous ethanol, dried, and placed in a vacuum chamber of an EBW-15CH electron beam welder for pulsed electron beam treatment. The specific pulsed electron beam treatment parameters were: electron beam power 4 kW, acceleration voltage 18 kV, and electron gun vacuum degree 7 × 10 -2 Pa, the scanning frequency is 5KHz, the number of pulses is 5 times, the pulse width is 3.5μs, and the scanning waveform is a sine wave.

[0029] (2) Chemical vapor deposition of graphene film: The pretreated bare optical fiber is placed in a CVD tube furnace, and an inert protective gas is introduced to heat it to 1000°C. The temperature is stabilized and maintained for 30 minutes. Then, the introduction of the protective gas is stopped and the carbon source gas is introduced instead. The reaction time is 30 minutes and the reaction is completed. The power is cut off, the carbon source gas is turned off, and the inert protective gas is introduced again to exhaust the carbon source gas. The CVD tube furnace is cooled to room temperature under the inert protective gas environment to obtain the graphene optical fiber.

[0030] In the step (2), the inert protective gas is hydrogen, argon or nitrogen.

[0031] The obtained graphene fiber has a bandwidth of 5350MHz﹒km in the 850nm working window, a bandwidth of 3560MHz﹒km in the 953nm working window, a bandwidth of 1043MHz﹒km in the 1300nm working window, and a bandwidth of 657MHz﹒km in the 1550nm working window.

[0032] The obtained graphene optical fiber has an attenuation coefficient of 2.2 dB / km in the 850 nm working window, an attenuation coefficient of 1.4 dB / km in the 953 nm working window, an attenuation coefficient of 0.4 dB / km in the 1300 nm working window, and an attenuation coefficient of 0.3 dB / km in the 1550 nm working window.

[0033] The obtained graphene optical fiber can also be applied in sensors, intelligent manufacturing, industrial big data, and aerospace fields.

[0034] like Figure 1 As shown, the obtained graphene optical fiber is mainly composed of a graphene film 1, a cladding 2 and a core 3 from the outside to the inside. The optical signal 4 is an optical signal generated by a laser or an LED light source.

[0035] Embodiment 2:

[0036] The graphene optical fiber prepared by the present invention has the following specific preparation steps:

[0037] (1) Electron beam fiber pretreatment: The bare optical fiber was pre-wiped with anhydrous ethanol, dried, and placed in a vacuum chamber in an electron beam device for pulsed electron beam treatment. The specific pulsed electron beam treatment parameters were: electron beam power of 8 kW, acceleration voltage of 23 kV, and electron gun vacuum of 7 × 10 -2 Pa, the scanning frequency is 10KHz, the number of pulses is 25 times, the pulse width is 2μs, and the scanning waveform is elliptical.

[0038] (2) Chemical vapor deposition of graphene film: The pretreated bare optical fiber is placed in a CVD tube furnace, and an inert protective gas is introduced to heat it to 1200°C. The temperature is stabilized and maintained for 20 minutes. Then, the introduction of the inert protective gas is stopped and replaced with a carbon source gas. The reaction time is 40 minutes and the reaction is completed. The power is cut off, the carbon source gas is turned off, and an inert protective gas is introduced again to exhaust the carbon source gas. The CVD tube furnace is kept in an inert protective gas environment until it cools to room temperature to obtain a graphene optical fiber.

[0039] The inert protective gas in step (2) is hydrogen, argon or nitrogen.

[0040] The obtained graphene optical fiber has a bandwidth of 6450MHz﹒km in the 850nm working window, a bandwidth of 4320MHz﹒km in the 953nm working window, a bandwidth of 2210MHz﹒km in the 1300nm working window, and a bandwidth of 936MHz﹒km in the 1550nm working window.

[0041] The obtained graphene optical fiber has an attenuation coefficient of 1.8 dB / km in the 850 nm working window, an attenuation coefficient of 1.1 dB / km in the 953 nm working window, an attenuation coefficient of 0.2 dB / km in the 1300 nm working window, and an attenuation coefficient of 0.1 dB / km in the 1550 nm working window.

[0042] Figure 2It is shown that the effective mode bandwidth of the graphene optical fiber of this embodiment in the working windows of 850nm, 953nm, 1300nm and 1550nm is higher than the effective mode bandwidth of the graphene optical fiber without electron beam treatment + chemical deposition in Comparative Example 1.

[0043] Figure 3 It is shown that the optical attenuation coefficient of the graphene optical fiber of this embodiment in the working windows of 850nm, 953nm, 1300nm and 1550nm is lower than that of the graphene optical fiber without electron beam treatment + chemical deposition in comparative example 1.

[0044] The obtained graphene optical fiber can also be applied in sensors, intelligent manufacturing, industrial big data, and aerospace fields.

[0045] Embodiment 3:

[0046] The graphene optical fiber prepared by the present invention has the following specific preparation steps:

[0047] (1) Electron beam fiber pretreatment: The bare optical fiber was pre-wiped with anhydrous ethanol, dried and placed in a vacuum chamber in an electron beam device for pulsed electron beam treatment. The specific processing parameters of the pulsed electron beam were as follows: the electron beam power was 12 kW, the acceleration voltage was 25 kV, and the vacuum degree of the electron gun was 7 × 10 -2 Pa, the scanning frequency is 6KHz, the number of pulses is 15 times, the pulse width is 3μs, and the scanning waveform is a triangle wave.

[0048] (2) Chemical vapor deposition of graphene film: The pretreated bare optical fiber is placed in a CVD tube furnace, and an inert protective gas is introduced to heat it to 1500°C. The temperature is stabilized and maintained for 30 minutes. Then, the introduction of the inert protective gas is stopped and the carbon source gas is introduced instead. The reaction time is 30 minutes and the reaction is completed. The power is cut off, the carbon source gas is turned off, and the inert protective gas is introduced again to exhaust the carbon source gas. The CVD tube furnace is cooled to room temperature under the inert protective gas environment to obtain the graphene optical fiber.

[0049] In the step (2), the inert protective gas is hydrogen, argon or nitrogen.

[0050] The obtained graphene fiber has a bandwidth of 5943MHz﹒km in the 850nm working window, a bandwidth of 3870MHz﹒km in the 953nm working window, a bandwidth of 1715MHz﹒km in the 1300nm working window, and a bandwidth of 743MHz﹒km in the 1550nm working window.

[0051] The obtained graphene optical fiber has an attenuation coefficient of 2dB / km in the 850nm working window, an attenuation coefficient of 1.2dB / km in the 953nm working window, an attenuation coefficient of 0.3dB / km in the 1300nm working window, and an attenuation coefficient of 0.2dB / km in the 1550nm working window.

[0052] The obtained graphene optical fiber can also be applied in sensors, intelligent manufacturing, industrial big data, and aerospace fields.

[0053] Example 4

[0054] The graphene optical fiber prepared by the present invention has the following specific preparation steps:

[0055] (1) Electron beam fiber pretreatment: The bare optical fiber was pre-wiped with anhydrous ethanol, dried, and placed in a vacuum chamber in an electron beam device for pulsed electron beam treatment. The specific processing parameters of the pulsed electron beam were as follows: the electron beam power was 15 kW, the acceleration voltage was 27 kV, and the vacuum degree of the electron gun was 7 × 10 -2 Pa, the scanning frequency is 8KHz, the number of pulses is 25 times, the pulse width is 3.5μs, and the scanning waveform is a square wave.

[0056] (2) Chemical vapor deposition of graphene film: The pretreated bare optical fiber is placed in a CVD tube furnace, and an inert protective gas is introduced to heat it to 1500°C. The temperature is stabilized and maintained for 30 minutes. Then, the introduction of the inert protective gas is stopped and the carbon source gas is introduced instead. The reaction time is 30 minutes and the reaction is completed. The power is cut off, the carbon source gas is turned off, and the inert protective gas is introduced again to exhaust the carbon source gas. The CVD tube furnace is cooled to room temperature under the inert protective gas environment to obtain the graphene optical fiber.

[0057] In the step (2), the inert protective gas is hydrogen, argon or nitrogen.

[0058] The obtained graphene fiber has a bandwidth of 5634MHz﹒km in the 850nm working window, 3605MHz﹒km in the 953nm working window, 1598MHz﹒km in the 1300nm working window, and 685MHz﹒km in the 1550nm working window.

[0059] The obtained graphene optical fiber has an attenuation coefficient of 2.1 dB / km in the 850 nm working window, an attenuation coefficient of 1.4 dB / km in the 953 nm working window, an attenuation coefficient of 0.5 dB / km in the 1300 nm working window, and an attenuation coefficient of 0.2 dB / km in the 1550 nm working window.

[0060] The obtained graphene optical fiber can also be applied in sensors, intelligent manufacturing, industrial big data, and aerospace fields.

[0061] The working parameter range of the pulsed electron beam selected in step (1) in the embodiment of the present invention is to ensure that the energy on the surface of the bare optical fiber can be evenly distributed on the surface and a sufficient number of nanoscale hole defects can be generated on the surface by controlling the corresponding electron beam parameters, which is conducive to the nucleation of carbon atoms and ultimately obtains a uniform graphene film.

[0062] Example 5

[0063] The graphene optical fiber prepared by the present invention has the following specific preparation steps:

[0064] (1) Electron beam fiber pretreatment: The bare optical fiber was pre-wiped with anhydrous ethanol, dried, and placed in a vacuum chamber in an electron beam device for pulsed electron beam treatment. The specific processing parameters of the pulsed electron beam were as follows: the electron beam power was 6 kW, the acceleration voltage was 10 kV, and the vacuum degree of the electron gun was 7 × 10 -2 Pa, the scanning frequency is 10KHz, the number of pulses is 25 times, the pulse width is 1μs, and the scanning waveform is a square wave.

[0065] (2) Chemical vapor deposition of graphene film: The pretreated bare optical fiber is placed in a CVD tube furnace, and an inert protective gas is introduced to heat it to 1500°C. The temperature is stabilized and maintained for 30 minutes. Then, the introduction of the inert protective gas is stopped and the carbon source gas is introduced instead. The reaction time is 30 minutes and the reaction is completed. The power is cut off, the carbon source gas is turned off, and the inert protective gas is introduced again to exhaust the carbon source gas. The CVD tube furnace is cooled to room temperature under the inert protective gas environment to obtain the graphene optical fiber.

[0066] The obtained graphene fiber has a bandwidth of 5138MHz﹒km in the 850nm working window, 3245MHz﹒km in the 953nm working window, 1023MHz﹒km in the 1300nm working window, and 595MHz﹒km in the 1550nm working window.

[0067] The obtained graphene optical fiber has an attenuation coefficient of 2.2 dB / km in the 850 nm working window, an attenuation coefficient of 1.6 dB / km in the 953 nm working window, an attenuation coefficient of 0.5 dB / km in the 1300 nm working window, and an attenuation coefficient of 0.2 dB / km in the 1550 nm working window.

[0068] The obtained graphene optical fiber can also be applied in sensors, intelligent manufacturing, industrial big data, and aerospace fields.

[0069] Comparative Example 1: Optical fiber without electron beam treatment + chemically deposited graphene was selected as the detection object.

[0070] Among them, the graphene film needs to be transferred from the copper foil or nickel foil to the optical fiber surface. The acid etching and transfer technology of the graphene film belongs to the existing technology. If the electron beam technology is not used, the nucleation of carbon atoms requires a lot of nucleation work, and it is impossible to obtain a complete graphene film on the bare optical fiber.

[0071] The obtained graphene optical fiber has a bandwidth of 4700MHz﹒km in the 850nm working window, a bandwidth of 2470MHz﹒km in the 953nm working window, a bandwidth of 850MHz﹒km in the 1300nm working window, and a bandwidth of 360MHz﹒km in the 1550nm working window.

[0072] The obtained graphene optical fiber has an attenuation coefficient of 2.4dB / km in the 850nm working window, an attenuation coefficient of 1.7dB / km in the 953nm working window, an attenuation coefficient of 0.6dB / km in the 1300nm working window, and an attenuation coefficient of 0.3dB / km in the 1550nm working window.

[0073] The graphene film prepared by the method of Comparative Example 1 will cause a large coating stress to form on the surface of the optical fiber, increasing the loss of the optical signal, so its performance is inferior to the optical performance of Examples 1-5.

[0074] The optical fiber bending performance of Examples 1-5 and Comparative Example 1 was tested using the macrobending additional loss test method of IEC-60793-1-47. The tested optical fiber was wound around a circle with a diameter of 15 mm and a diameter of 30 mm, respectively, and then the circle was released to test the change in optical power before and after bending, and the change value was taken as the macrobending additional loss value. The macrobending additional loss values ​​of Examples 1-5 and Comparative Example 1 are shown in Table 1.

[0075] Table 1 Comparison of bending properties of Examples 1-5 and Comparative Example 1 under different spectral conditions

[0076]

[0077]

[0078] It can be seen from Table 1 that compared with Comparative Example 1, the graphene optical fibers of Examples 1-5 have excellent bending properties under different spectral conditions. The data show that when the bending radius of the graphene optical fiber prepared by the present invention is greater than 7.5 mm, a low macrobending additional loss can be maintained under four spectral conditions.

Claims

1. A method for preparing a graphene optical fiber, characterized in that: The specific preparation steps are as follows: Step (1), optical fiber pretreatment: the surface of the bare optical fiber is treated with anhydrous ethanol and then dried, placed in a vacuum chamber, and subjected to pulsed electron beam treatment; the pulsed electron beam power is 4-15 kW, the acceleration voltage is 10-27 kV, and the vacuum degree of the electron gun is 7×10 -2 Pa, the scanning frequency is 5-10KHz, the number of pulses is 5-25 times, the pulse width is 1-3.5μs, and the scanning waveform is one of a sine wave, a square wave, a triangle wave, an ellipse, and a circle; the pulsed electron beam is irradiated on the surface of the bare optical fiber to generate nanometer-scale hole defects; Step (2), chemical vapor deposition of graphene film: placing the pretreated bare optical fiber into a CVD tube furnace, introducing an inert protective gas and heating to 1000-1500° C., stabilizing the temperature and maintaining it for 20-40 minutes; stopping the introduction of the inert protective gas, introducing a carbon source gas, and reacting for 30-50 minutes until the reaction is complete; turning off the carbon source gas, and then introducing an inert protective gas to exhaust the carbon source gas, and cooling the CVD tube furnace to room temperature under the inert protective gas environment to obtain a graphene optical fiber.

2. The method for preparing a graphene optical fiber according to claim 1, characterized in that: The pulse electron beam power is 6-12 kW, the acceleration voltage is 18-25 kV, and the vacuum degree of the electron gun is 7×10 -2 Pa, the scanning frequency is 6-8KHz, and the pulse width is 2-3μs.

3. The method for preparing a graphene optical fiber according to claim 1 or 2, characterized in that: The inert protective gas is hydrogen, argon or nitrogen.

4. The method for preparing a graphene optical fiber according to claim 3, characterized in that: The carbon source gas is methane, carbon monoxide, ethylene, propylene, butene, benzene, acetylene or n-hexane.

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