CN107516811A - Optical fiber amplifier and multi-stage optical fiber amplifier system - Google Patents
Optical fiber amplifier and multi-stage optical fiber amplifier system Download PDFInfo
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 100
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- H—ELECTRICITY
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- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
- H01S3/06758—Tandem amplifiers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
- H01S3/094015—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre with pump light recycling, i.e. with reinjection of the unused pump light back into the fiber, e.g. by reflectors or circulators
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Abstract
Description
技术领域technical field
本发明涉及激光技术领域，更具体地，涉及光纤放大器及多级光纤放大器系统。The invention relates to the field of laser technology, more specifically, to an optical fiber amplifier and a multistage optical fiber amplifier system.
背景技术Background technique
光纤激光器因其优越的特性，例如优异的光束质量、高的功率和功率密度、易于冷却、高的稳定性和可靠性等，而受到人们的日益关注，并在多个领域有着广泛的应用。Due to their superior characteristics, such as excellent beam quality, high power and power density, easy cooling, high stability and reliability, etc., fiber lasers have attracted increasing attention and have been widely used in many fields.
目前，实现高功率激光器输出时，普遍采用的是高功率光纤放大器结构。在光纤放大器中，往往希望泵浦吸收充分，才能实现最大的泵浦利用率，而充分的泵浦吸收意味着需要更长的增益光纤。现有的光纤放大器主要由泵浦源、泵浦耦合器和增益光纤组成，其中，增益光纤的长度通常采用通过理论计算得到的长度，通常为光纤放大器达到最大提取效率时对应的增益光纤的长度，也称预设长度。采用预设长度的增益光纤，可以使光纤放大器实现最大的泵浦利用率，但是由于采用的增益光纤的长度较长，会带来极为严重的非线性效应，尤其是在高功率光纤放大器中。因此，在高功率光纤放大器的发展中，非线性效应成为阻碍其发展的重要瓶颈。具体来看，光纤中受激拉曼散射阈值公式为其中，Pth1为受激拉曼散射阈值，Aeff为光纤纤芯的有效横截面积，Leff为光纤的有效长度，gR为拉曼增益常数。光纤中受激布里渊散射阈值公式为其中，Pth2为受激布里渊散射阈值，K为偏振因子，Aeff为光纤纤芯的有效横截面积，gB为布里渊增益常数，Leff为光纤的有效长度。上面两个公式可以直观的表明各个非线性效应阈值与光纤的有效长度成反比，因此若为了保证放大级高的输出功率和高的泵浦效率而一味增加增益光纤长度，势必会导致非线性效应愈发严重，并影响着激光器的输出光束质量和输出功率。At present, the high-power fiber amplifier structure is commonly used to realize high-power laser output. In fiber amplifiers, it is often hoped that the pump absorption is sufficient to achieve the maximum pump utilization, and sufficient pump absorption means that a longer gain fiber is required. Existing fiber amplifiers are mainly composed of a pump source, a pump coupler, and a gain fiber. The length of the gain fiber is usually the length obtained through theoretical calculation, which is usually the length of the gain fiber corresponding to the maximum extraction efficiency of the fiber amplifier. , also known as preset length. Using a preset length of gain fiber can make the fiber amplifier achieve the maximum pump utilization, but due to the long length of the gain fiber used, it will bring extremely serious nonlinear effects, especially in high-power fiber amplifiers. Therefore, in the development of high-power fiber amplifiers, the nonlinear effect has become an important bottleneck hindering its development. Specifically, the stimulated Raman scattering threshold formula in optical fiber is Among them, P th1 is the stimulated Raman scattering threshold, A eff is the effective cross-sectional area of the fiber core, L eff is the effective length of the fiber, and g R is the Raman gain constant. The stimulated Brillouin scattering threshold formula in optical fiber is Among them, P th2 is the stimulated Brillouin scattering threshold, K is the polarization factor, A eff is the effective cross-sectional area of the fiber core, g B is the Brillouin gain constant, and L eff is the effective length of the fiber. The above two formulas can intuitively show that each nonlinear effect threshold is inversely proportional to the effective length of the fiber. Therefore, if the length of the gain fiber is blindly increased in order to ensure high output power and high pump efficiency of the amplifier stage, it will inevitably lead to nonlinear effects. It is becoming more and more serious and affects the output beam quality and output power of the laser.
为解决上述问题，现有技术中给出了一种光纤放大器，将光纤放大器中的增益光纤长度设置为小于预设长度，这样虽然可以减小增益光纤带来的非线性效应，但是同时会导致泵浦不能被充分吸收，不能实现最大的泵浦利用率，进而会影响光纤放大器的输出功率。In order to solve the above problems, a fiber amplifier is provided in the prior art, and the length of the gain fiber in the fiber amplifier is set to be less than the preset length. Although this can reduce the nonlinear effect brought by the gain fiber, it will also cause The pump cannot be fully absorbed, and the maximum pump utilization cannot be achieved, which in turn will affect the output power of the fiber amplifier.
发明内容Contents of the invention
为克服上述问题或者至少部分地解决上述问题，本发明提供了一种光纤放大器及多级光纤放大器系统。To overcome the above problems or at least partly solve the above problems, the present invention provides an optical fiber amplifier and a multi-stage optical fiber amplifier system.
一方面，本发明提供了一种光纤放大器，包括：泵浦耦合器、增益光纤和泵浦反馈装置；其中，所述泵浦耦合器用于将泵浦光耦合至所述增益光纤；所述增益光纤的长度小于预设长度，其中，所述预设长度为所述光纤放大器达到最大提取效率时对应的所述增益光纤的长度；所述泵浦反馈装置用于将所述增益光纤内的残余泵浦光与激光分离，并将所述残余泵浦光返回至所述泵浦耦合器。On the one hand, the present invention provides a kind of optical fiber amplifier, comprising: a pumping coupler, a gain fiber and a pumping feedback device; wherein, the pumping coupler is used to couple pump light to the gain fiber; the gain The length of the optical fiber is less than a preset length, wherein the preset length is the length of the gain fiber corresponding to when the fiber amplifier reaches the maximum extraction efficiency; the pump feedback device is used to convert the residual in the gain fiber The pump light is separated from the laser light and the residual pump light is returned to the pump coupler.
优选地，所述泵浦耦合器还用于向所述光纤放大器内输入种子光；Preferably, the pump coupler is also used to input seed light into the optical fiber amplifier;
相应地，所述泵浦反馈装置还用于输出激光。Correspondingly, the pump feedback device is also used to output laser light.
优选地，所述泵浦反馈装置具体包括：具有一个输入端和M个输出端的，其中M为大于1的整数；所述分束器的输入端与所述增益光纤的一端连接，所述分束器的M-1个输出端中每一个输出端均与所述泵浦耦合器的一个输入端连接。Preferably, the pump feedback device specifically includes: one input terminal and M output terminals, wherein M is an integer greater than 1; the input terminal of the beam splitter is connected to one end of the gain fiber, and the splitter Each of the M-1 output terminals of the beamer is connected to an input terminal of the pump coupler.
优选地，当M>2时，所述泵浦反馈装置还包括：n个合束器，所述合束器具有N个输入端和一个输出端，其中n为不小于1的整数，n*N＝M-1；所述n个合束器中的每一个输入端均与所述分束器的一个输出端连接，所述n个合束器中的每一个输出端均与所述泵浦耦合器的一个输入端连接。Preferably, when M>2, the pump feedback device further includes: n beam combiners, the beam combiner has N input terminals and one output terminal, wherein n is an integer not less than 1, n* N=M-1; each input end of the n beam combiners is connected to an output end of the beam splitter, and each output end of the n beam combiners is connected to the pump Connect to one input of the Pu coupler.
优选地，所述分束器的输入端与所述增益光纤的一端之间还设置有锥形适配器；所述锥形适配器第一端的光纤横截面积小于第二端的光纤横截面积，所述锥形适配器的第一端与所述增益光纤的一端连接，所述锥形适配器的第二端与所述分束器的输入端连接。Preferably, a tapered adapter is also provided between the input end of the beam splitter and one end of the gain fiber; the cross-sectional area of the optical fiber at the first end of the tapered adapter is smaller than the cross-sectional area of the optical fiber at the second end, so The first end of the tapered adapter is connected to one end of the gain fiber, and the second end of the tapered adapter is connected to the input end of the beam splitter.
优选地，所述泵浦反馈装置还用于向所述光纤放大器内输入种子光；相应地，所述泵浦耦合器还用于输出激光。Preferably, the pumping feedback device is also used for inputting seed light into the optical fiber amplifier; correspondingly, the pumping coupler is also used for outputting laser light.
优选地，所述泵浦反馈装置具体包括：具有2个输入端和M个输出端的分束器，其中M为大于或等于1的整数；所述分束器的一个输入端用于输入种子光，所述分束器的另一个输入端与所述增益光纤的一端连接，所述分束器的另一个输入端用于将所述种子光输出至所述增益光纤，还用于接收所述增益光纤内的残余泵浦光；所述分束器的M个输出端中每一个输出端均与所述泵浦耦合器的一个输入端连接。Preferably, the pump feedback device specifically includes: a beam splitter with 2 input ports and M output ports, wherein M is an integer greater than or equal to 1; one input port of the beam splitter is used to input the seed light , the other input end of the beam splitter is connected to one end of the gain fiber, the other input end of the beam splitter is used to output the seed light to the gain fiber, and is also used to receive the Residual pump light in the gain fiber; each of the M output ends of the beam splitter is connected to an input end of the pump coupler.
优选地，当M>1时，所述泵浦反馈装置还包括：n个合束器，每个合束器具有N个输入端和一个输出端，其中n为不小于1的整数，n*N＝M；n个所述合束器中的每一个输入端均与所述分束器的一个输出端连接，n个所述合束器中的每一个输出端均与所述泵浦耦合器的一个输入端连接。Preferably, when M>1, the pump feedback device further includes: n beam combiners, each beam combiner has N input terminals and one output terminal, wherein n is an integer not less than 1, n* N=M; each input end of the n beam combiners is connected to an output end of the beam splitter, and each output end of the n beam combiners is coupled to the pump connected to one input of the device.
优选地，所述分束器的另一个输入端与所述增益光纤的一端之间还设置有锥形适配器；所述锥形适配器第一端的光纤横截面积小于第二端的光纤横截面积，所述锥形适配器的第一端与所述增益光纤的一端连接，所述锥形适配器的第二端与所述泵浦反馈装置的输入端连接。Preferably, a tapered adapter is also provided between the other input end of the beam splitter and one end of the gain fiber; the cross-sectional area of the fiber at the first end of the tapered adapter is smaller than the cross-sectional area of the fiber at the second end , the first end of the tapered adapter is connected to one end of the gain fiber, and the second end of the tapered adapter is connected to the input end of the pump feedback device.
另一方面，本发明提供了一种多级光纤放大器系统，包括至少两个依次设置的、上述的光纤放大器。In another aspect, the present invention provides a multi-stage optical fiber amplifier system, comprising at least two above-mentioned optical fiber amplifiers arranged in sequence.
本发明提供的一种光纤放大器，通过将增益光纤的长度设置为小于预设长度，减小增益光纤对种子光纤的重吸收。同时，利用泵浦反馈装置将增益光纤的长度变短后得到的残余泵浦光返回至泵浦耦合器中，提高了光纤放大器的泵浦效率，进而实现了光纤放大器的高功率输出。The invention provides a fiber amplifier, by setting the length of the gain fiber to be less than the preset length, so as to reduce the reabsorption of the gain fiber to the seed fiber. At the same time, the residual pump light obtained after the length of the gain fiber is shortened is returned to the pump coupler by using the pump feedback device, which improves the pumping efficiency of the fiber amplifier and realizes the high power output of the fiber amplifier.
附图说明Description of drawings
图1为本发明一实施例提供的一种光纤放大器的结构示意图；Fig. 1 is a schematic structural view of an optical fiber amplifier provided by an embodiment of the present invention;
图2为本发明另一实施例提供的一种光纤放大器的结构示意图；Fig. 2 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图3为本发明另一实施例提供的一种光纤放大器的结构示意图；Fig. 3 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图4为本发明另一实施例提供的一种光纤放大器的结构示意图；Fig. 4 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图5为本发明另一实施例提供的一种光纤放大器的结构示意图；Fig. 5 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图6为本发明另一实施例提供的一种多级光纤放大器系统的结构示意图；6 is a schematic structural diagram of a multi-stage optical fiber amplifier system provided by another embodiment of the present invention;
图7为本发明又一实施例提供的一种光纤放大器的结构示意图；Fig. 7 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图8为本发明又一实施例提供的一种光纤放大器的结构示意图；Fig. 8 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图9为本发明又一实施例提供的一种光纤放大器的结构示意图；Fig. 9 is a schematic structural diagram of an optical fiber amplifier provided by another embodiment of the present invention;
图10为本发明又一实施例提供的一种多级光纤放大器系统的结构示意图。Fig. 10 is a schematic structural diagram of a multi-stage optical fiber amplifier system provided by another embodiment of the present invention.
具体实施方式detailed description
下面结合附图和实施例，对本发明的具体实施方式作进一步详细描述。以下实施例用于说明本发明，但不用来限制本发明的范围。The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
如图1所示，本发明的一实施例中提供了一种光纤放大器，包括：泵浦耦合器11、增益光纤12和泵浦反馈装置13。As shown in FIG. 1 , an embodiment of the present invention provides a fiber amplifier, including: a pump coupler 11 , a gain fiber 12 and a pump feedback device 13 .
其中，所述泵浦耦合器11用于将泵浦光耦合至所述增益光纤12；所述增益光纤12的长度小于预设长度。这里，所述预设长度为所述光纤放大器达到最大提取效率时对应的所述增益光纤12的长度；Wherein, the pump coupler 11 is used to couple the pump light to the gain fiber 12; the length of the gain fiber 12 is less than a preset length. Here, the preset length is the length of the gain fiber 12 corresponding to when the fiber amplifier reaches the maximum extraction efficiency;
所述泵浦反馈装置13用于将所述增益光纤12内的残余泵浦光与激光分离，并将所述残余泵浦光返回至所述泵浦耦合器11。The pump feedback device 13 is used to separate the residual pump light in the gain fiber 12 from the laser light, and return the residual pump light to the pump coupler 11 .
具体地，现有技术中为保证光纤放大器能够实现最大的泵浦利用率，将光纤放大器中增益光纤的长度设置为光纤放大器达到最大提取效率时对应的增益光纤的长度，也就是预设长度。这样的结果往往使得非线性效应更易产生，尤其在多级放大器结构中，严重影响着光纤放大器的输出光束质量和输出功率。另外，过长的增益光纤会造成输出激光的重吸收问题，这是由掺杂离子的吸收曲线决定的，即使增益光纤的吸收截面较小，在长增益光纤的作用下，也会对增益光纤内产生的激光进行重吸收，从而导致光纤放大器的效率下降。Specifically, in the prior art, in order to ensure that the fiber amplifier can achieve maximum pump utilization, the length of the gain fiber in the fiber amplifier is set to the length of the gain fiber corresponding to when the fiber amplifier reaches the maximum extraction efficiency, that is, the preset length. Such a result often makes nonlinear effects more likely to occur, especially in the multi-stage amplifier structure, which seriously affects the output beam quality and output power of the fiber amplifier. In addition, too long gain fiber will cause reabsorption of the output laser, which is determined by the absorption curve of doped ions. Even if the absorption cross section of the gain fiber is small, under the action of the long gain fiber, it will also affect the The laser light generated in the laser is reabsorbed, which leads to a decrease in the efficiency of the fiber amplifier.
另一方面，在一些工作在特殊波长的光纤激光器中(如掺镱光纤激光器的975nm～1030nm波段)，如果增益光纤长于某一特定值，所需波长的激光就无法振荡产生出来。这是由于掺镱光纤在975nm～1030nm附近具有很大的吸收截面，远高于1050nm以上波段近乎为零的吸收截面，因此重吸收严重。重吸收提高了1010nm～1030nm激光振荡输出的阈值，导致激光难以激发出来。On the other hand, in some fiber lasers working at special wavelengths (such as the 975nm-1030nm band of ytterbium-doped fiber lasers), if the gain fiber is longer than a certain value, the required wavelength of laser light cannot be oscillated. This is because the ytterbium-doped fiber has a large absorption cross-section near 975nm to 1030nm, which is much higher than the almost zero absorption cross-section in the band above 1050nm, so the reabsorption is serious. Reabsorption increases the threshold of laser oscillation output at 1010nm to 1030nm, making it difficult to excite the laser.
因此，基于以上，本发明提供了一种光纤放大器，本发明提供的光纤放大器中，采用的增益光纤的长度可远小于预设长度，这将会有效的抑制非线性效应的产生，同时有效避免增益光纤对内部产生的激光的重吸收。同时，小于预设长度的增益光纤会导致泵浦吸收降低，产生未被利用的泵浦光，即残余泵浦光。通过对残余泵浦光的循环利用，提高光纤放大器的泵浦效率，进而实现高功率的光纤放大器的输出功率、激光效率和光束质量的三重保证。Therefore, based on the above, the present invention provides an optical fiber amplifier. In the optical fiber amplifier provided by the present invention, the length of the gain fiber used can be much smaller than the preset length, which will effectively suppress the generation of nonlinear effects and effectively avoid Gain fiber reabsorption of internally generated laser light. At the same time, a gain fiber with a length shorter than a predetermined length will result in reduced pump absorption, resulting in unused pump light, that is, residual pump light. By recycling the residual pump light, the pumping efficiency of the fiber amplifier is improved, and then the triple guarantee of the output power, laser efficiency and beam quality of the high-power fiber amplifier is realized.
增益光纤内的残余泵浦光的含量与增益光纤的吸收系数有关，例如增益光纤的吸收系数为1.2dB/m时，预设长度的增益光纤内，残余泵浦光的含量通常小于增益光纤内所有泵浦光的10％。当增益光纤的长度小于预设长度时，会使残余泵浦光的含量大于所有泵浦光的10％。作为优选方案，可将增益光纤的长度缩短为预设长度的30％-50％，这样，增益光纤内的残余泵浦光的含量可达30％左右。The content of residual pump light in the gain fiber is related to the absorption coefficient of the gain fiber. For example, when the absorption coefficient of the gain fiber is 1.2dB/m, the content of the residual pump light in the gain fiber with a preset length is usually smaller than that in the gain fiber 10% of all pump light. When the length of the gain fiber is less than the preset length, the content of the residual pump light will be greater than 10% of all the pump light. As a preferred solution, the length of the gain fiber can be shortened to 30%-50% of the preset length, so that the content of residual pump light in the gain fiber can reach about 30%.
泵浦耦合器是一种将泵浦光耦合至增益光纤内的光器件，泵浦耦合器的输入端用于向光纤放大器内输入泵浦光，泵浦光经泵浦耦合器耦合至增益光纤内，增益光纤中的增益介质，即增益光纤的纤芯内的掺杂离子吸收泵浦光，被激发至高能态，处于高能态的粒子快速弛豫至能量较低的激发态，当种子光进入增益光纤后，激发态上的粒子产生受激辐射，并跃迁至低能态释放出储能，从而将种子光放大，形成激光。由于激光中混合有残余泵浦光，通过泵浦反馈装置将增益光纤内的残余泵浦光与激光分离，并将得到的残余泵浦光返回至泵浦耦合器的输入端，循环利用泵浦光后，得到高效率、高功率的激光输出。The pump coupler is an optical device that couples the pump light into the gain fiber. The input end of the pump coupler is used to input the pump light into the fiber amplifier, and the pump light is coupled to the gain fiber through the pump coupler. Inside, the gain medium in the gain fiber, that is, the doped ions in the core of the gain fiber absorb the pump light and are excited to a high-energy state, and the particles in the high-energy state relax rapidly to an excited state with lower energy. When the seed light After entering the gain fiber, the particles in the excited state produce stimulated radiation, and transition to a low-energy state to release the stored energy, thereby amplifying the seed light and forming a laser. Since the laser is mixed with residual pump light, the residual pump light in the gain fiber is separated from the laser through the pump feedback device, and the obtained residual pump light is returned to the input end of the pump coupler to recycle the pump After the light is turned on, a high-efficiency, high-power laser output is obtained.
本实施例中提供的光纤放大器可以为前向泵浦光纤放大器，也可以为后向泵浦光纤放大器。The optical fiber amplifier provided in this embodiment may be a forward-pumped optical fiber amplifier or a backward-pumped optical fiber amplifier.
本实施例中，通过将增益光纤的长度设置为小于预设长度，有效抑制非线性效应的产生，减小增益光纤对内部产生的激光的重吸收。同时，利用泵浦反馈装置将增益光纤的长度变短后得到的残余泵浦光返回至泵浦耦合器中，提高了光纤放大器的泵浦效率，进而实现了光纤放大器的高功率输出。In this embodiment, by setting the length of the gain fiber to be less than the preset length, the occurrence of nonlinear effects is effectively suppressed, and the reabsorption of the laser light generated inside the gain fiber is reduced. At the same time, the residual pump light obtained after the length of the gain fiber is shortened is returned to the pump coupler by using the pump feedback device, which improves the pumping efficiency of the fiber amplifier and realizes the high power output of the fiber amplifier.
在上述实施例的基础上，所述泵浦耦合器还用于向所述光纤放大器内输入种子光；On the basis of the above embodiments, the pump coupler is also used to input seed light into the optical fiber amplifier;
相应地，所述泵浦反馈装置还用于输出激光。Correspondingly, the pump feedback device is also used to output laser light.
具体地，本实施例中，泵浦耦合器的一个输入端还可作为整个光纤放大器的输入端，用于输入种子光。泵浦耦合器、增益光纤和泵浦反馈装置依次连接后，泵浦光和种子光分别通过泵浦耦合器的输入端输入至增益光纤内，增益光纤内的掺杂物质在泵浦光的作用下发生跃迁并弛豫至能量较低的激发态，种子光又使得激发态上的粒子产生受激辐射，并跃迁至低能态释放出能量，使种子光得到放大，产生激光。Specifically, in this embodiment, one input end of the pump coupler can also be used as an input end of the entire optical fiber amplifier for inputting seed light. After the pump coupler, gain fiber and pump feedback device are connected in sequence, the pump light and seed light are respectively input into the gain fiber through the input end of the pump coupler, and the dopant in the gain fiber plays a role in the pump light The seed light makes the particles in the excited state produce stimulated radiation, and transitions to a low-energy state to release energy, which amplifies the seed light and generates laser light.
本实施例中，提供了一种前向泵浦光纤放大器，使泵浦光与种子光通过泵浦耦合器一起耦合至增益光纤内。这种光纤放大器通过泵浦反馈装置将残余泵浦光反馈至泵浦耦合器的输入端，使残余泵浦光得到重复利用，能充分提高光纤放大器的功率。In this embodiment, a forward-pumped fiber amplifier is provided, so that the pump light and the seed light are coupled into the gain fiber through the pump coupler. The optical fiber amplifier feeds back the residual pumping light to the input end of the pumping coupler through the pumping feedback device, so that the residual pumping light can be reused, and the power of the optical fiber amplifier can be fully increased.
如图2所示，在上述实施例的基础上，光纤放大器中可包括：种子装置14和泵浦装置15。种子装置14和泵浦装置15分别与泵浦耦合器11的输入端连接。其中，种子装置14可作为光纤放大器的种子源，为光纤放大器提供种子光。由种子装置14发出的种子光经过泵浦耦合器11注耦合至增益光纤12中进行泵浦抽运放大。泵浦装置15可作为光纤放大器的泵浦源，为光纤放大器提供泵浦光。由泵浦装置15发出的泵浦光同样通过泵浦耦合器耦合至增益光纤12，激发增益光纤12内的掺杂离子。As shown in FIG. 2 , on the basis of the above embodiments, the optical fiber amplifier may include: a seed device 14 and a pump device 15 . The seed device 14 and the pump device 15 are respectively connected to the input end of the pump coupler 11 . Wherein, the seed device 14 can be used as a seed source of the optical fiber amplifier, providing seed light for the optical fiber amplifier. The seed light emitted by the seed device 14 is coupled to the gain fiber 12 through the pump coupler 11 for pumping and pumping amplification. The pumping device 15 can be used as a pumping source of the optical fiber amplifier to provide pumping light for the optical fiber amplifier. The pump light emitted by the pump device 15 is also coupled to the gain fiber 12 through the pump coupler to excite dopant ions in the gain fiber 12 .
本实施例中，通过设置种子装置和泵浦装置，可以使光纤放大器持续工作，不间断的产生高功率的激光。In this embodiment, by setting the seed device and the pumping device, the optical fiber amplifier can be continuously operated to generate high-power laser light without interruption.
在上述实施例的基础上，所述泵浦反馈装置13具体包括：具有一个输入端和M个输出端的分束器131，其中M为大于1的整数；On the basis of the above-mentioned embodiments, the pumping feedback device 13 specifically includes: a beam splitter 131 having one input terminal and M output terminals, wherein M is an integer greater than 1;
所述分束器131的输入端与所述增益光纤的一端连接，所述分束器131的M-1个输出端中每一个输出端均与所述泵浦耦合器11的一个输入端连接。The input end of the beam splitter 131 is connected to one end of the gain fiber, and each of the M-1 output ends of the beam splitter 131 is connected to an input end of the pump coupler 11 .
具体地，如图3所示，图3中以泵浦耦合器11的输入端连接有一个种子装置、六个泵浦装置为例。采用六个泵浦装置是为保证向增益光纤提供充足的泵浦光，但本发明并不具体限定泵浦装置的数量。图3中M＝2，分束器131的一个输出端与泵浦耦合器11的一个输入端连接，另一个输出端用于输出种子光放大后得到的激光。由于残余泵浦光大部分位于增益光纤的包层区域，所以分束器131可以通过数值孔径的不同来区分残余泵浦光和激光。Specifically, as shown in FIG. 3 , in FIG. 3 , it is taken as an example that one seed device and six pump devices are connected to the input end of the pump coupler 11 . The use of six pumping devices is to ensure sufficient pumping light for the gain fiber, but the present invention does not specifically limit the number of pumping devices. In FIG. 3 , M=2, one output end of the beam splitter 131 is connected to one input end of the pumping coupler 11 , and the other output end is used to output the laser light obtained by amplifying the seed light. Since most of the residual pump light is located in the cladding region of the gain fiber, the beam splitter 131 can distinguish the residual pump light from the laser light through the difference in numerical aperture.
本实施例中，设置了多个泵浦装置，为光纤放大器提供了充足的泵浦光。同时，还将分束器的一个输出端与泵浦耦合器的输入端连接，使增益光纤内产生的残余泵浦光可以经泵浦耦合器的输入端，再次进入增益光纤，以达到重复利用的目的，进而节约了资源，提高了光纤放大器的效率。In this embodiment, multiple pumping devices are provided to provide sufficient pumping light for the fiber amplifier. At the same time, one output end of the beam splitter is connected to the input end of the pump coupler, so that the residual pump light generated in the gain fiber can pass through the input end of the pump coupler and enter the gain fiber again to achieve reuse. The purpose, thereby saving resources and improving the efficiency of the optical fiber amplifier.
在上述实施例的基础上，当M>2时，所述泵浦反馈装置还包括：n个合束器，每个合束器具有N个输入端和一个输出端，其中n为不小于1的整数，n*N＝M-1；On the basis of the above embodiment, when M>2, the pump feedback device further includes: n beam combiners, each beam combiner has N input terminals and one output terminal, wherein n is not less than 1 An integer of n*N=M-1;
所述n个合束器中的每一个输入端均与所述分束器的一个输出端连接，所述n个合束器中的每一个输出端均与所述泵浦耦合器的一个输入端连接。Each input end of the n beam combiners is connected to an output end of the beam splitter, and each output end of the n beam combiners is connected to an input of the pump coupler end connection.
具体地，如图4所示，图4与图3的不同之处仅在于，图4中采用了具有一个输入端和7个输出端的分束器131作为泵浦反馈装置13，图4中共有2个合束器，每个合束器具有3个输入端和一个输出端，即M＝7，n＝2，N＝3。其中，分束器131的6个输出端分上下各3个，上面3个输出端中的每一个均与合束器132的一个输入端连接，该合束器132的输出端与泵浦耦合器11的输入端连接。下面3个输出端中的每一个均与合束器133的一个输入端连接，该合束器133的输出端也与泵浦耦合器11的输入端连接。Specifically, as shown in FIG. 4, the only difference between FIG. 4 and FIG. 3 is that in FIG. 4, a beam splitter 131 with one input end and seven output ends is used as the pumping feedback device 13. In FIG. 2 beam combiners, each beam combiner has 3 input terminals and one output terminal, that is, M=7, n=2, N=3. Wherein, the 6 output ends of the beam splitter 131 are divided into three upper and lower ones, and each of the upper three output ends is connected with an input end of the beam combiner 132, and the output end of the beam combiner 132 is coupled with the pump The input terminal of device 11 is connected. Each of the lower three outputs is connected to an input of a beam combiner 133 whose output is also connected to the input of the pump coupler 11 .
需要说明的是，本发明并不具体限定分束器或合束器输入端或输出端的数量。但是使用输出端更多的分束器可以使增益光纤内的残余泵浦光被更充分的分离并利用。It should be noted that the present invention does not specifically limit the number of input ports or output ports of the beam splitter or the beam combiner. But using more beam splitters at the output can make the residual pump light in the gain fiber be more fully separated and utilized.
在上述实施例的基础上，所述分束器的输入端与所述增益光纤的一端之间还可设置有锥形适配器；On the basis of the above embodiments, a tapered adapter may also be provided between the input end of the beam splitter and one end of the gain fiber;
所述锥形适配器第一端的光纤横截面积小于第二端的光纤横截面积，所述锥形适配器的第一端与所述增益光纤的一端连接，所述锥形适配器的第二端与所述分束器的输入端连接。The optical fiber cross-sectional area of the first end of the tapered adapter is smaller than the optical fiber cross-sectional area of the second end, the first end of the tapered adapter is connected to one end of the gain fiber, and the second end of the tapered adapter is connected to The input of the beam splitter is connected.
具体地，如图5所示，图5与图4的区别仅在于，在分束器131的输入端与所述增益光纤12的一端之间还设置有锥形适配器17。锥形适配器17的第一端与增益光纤12的一端连接，第二端与分束器131的输入端连接。由于残余泵浦光大部分位于增益光纤的包层区域，所以增加包层区域占整个光纤端面的比例，可提升残余泵浦光的反馈效率，从而提高光纤放大器的效率。所以本实施例中增加了锥形适配器17，使增益光纤的纤芯保持大小不变，将增益光纤的端面面积整体增加，将小口径的增益光纤转化至大口径的光纤，此时端面中包层区域所占比例将增加，大口径的光纤再与分束器131的输入端连接。Specifically, as shown in FIG. 5 , the only difference between FIG. 5 and FIG. 4 is that a tapered adapter 17 is provided between the input end of the beam splitter 131 and one end of the gain fiber 12 . The first end of the tapered adapter 17 is connected to one end of the gain fiber 12 , and the second end is connected to the input end of the beam splitter 131 . Since most of the residual pump light is located in the cladding region of the gain fiber, increasing the ratio of the cladding region to the entire fiber end face can improve the feedback efficiency of the residual pump light, thereby improving the efficiency of the fiber amplifier. Therefore, in this embodiment, a tapered adapter 17 is added to keep the size of the core of the gain fiber unchanged, increase the overall area of the end face of the gain fiber, and convert the small-diameter gain fiber into a large-diameter fiber. The proportion of the layer area will increase, and the optical fiber with large diameter is connected to the input end of the beam splitter 131 again.
本发明另一实施例提供了一种多级光纤放大器系统，包括至少两个依次设置的、如上述实施例所述的前向泵浦光纤放大器。Another embodiment of the present invention provides a multi-stage optical fiber amplifier system, including at least two sequentially arranged forward-pumped optical fiber amplifiers as described in the above embodiments.
作为优选方案，多级光纤放大器系统中每相邻的两个光纤放大器，前一个光纤放大器输出的激光为后一个光纤放大器的种子光。As a preferred solution, for every two adjacent fiber amplifiers in the multi-stage fiber amplifier system, the laser output from the previous fiber amplifier is the seed light of the latter fiber amplifier.
具体地，如图6所示，图6中显示的前向泵浦的多级光纤放大器系统中包括三个依次设置的、如上述实施例所述的光纤放大器，其中，第一个光纤放大器作为一级放大，第二个光纤放大器作为二级放大，第三个光纤放大器作为三级放大。第一个光纤放大器的一个输入端连接有种子装置，用于为多级光纤放大器系统提供种子光，第一个光纤放大器用于输出激光的输出端与第二个光纤放大器用于输入种子光的输入端连接，即将一级放大得到的激光作为种子光输入至第二个光纤放大器中进行二级放大，同样地，第二个光纤放大器用于输出激光的输出端与第三个光纤放大器用于输入种子光的输入端连接，即将二级放大得到的激光作为种子光输入至第三个光纤放大器中进行三级放大，最终通过第三个光纤放大器输出经过三级放大的激光。Specifically, as shown in Figure 6, the forward-pumped multistage fiber amplifier system shown in Figure 6 includes three fiber amplifiers arranged in sequence as described in the above embodiment, wherein the first fiber amplifier is used as The first stage of amplification, the second fiber amplifier as the second stage of amplification, and the third fiber optic amplifier as the third stage of amplification. One input end of the first fiber amplifier is connected with a seed device, which is used to provide seed light for the multi-stage fiber amplifier system. The output end of the first fiber amplifier is used to output laser light and the second fiber amplifier is used to input seed light. The input end is connected, that is, the laser light obtained by the primary amplification is input into the second optical fiber amplifier as the seed light for secondary amplification. Similarly, the output end of the second optical fiber amplifier is used to output the laser and the third optical fiber amplifier is used for The input end of the input seed light is connected, that is, the laser light obtained by the secondary amplification is input to the third optical fiber amplifier as the seed light for three-stage amplification, and finally the third-stage amplified laser is output through the third optical fiber amplifier.
本实施例提供的多级光纤放大器系统，可以使输出的激光的功率成倍增加。进而实现高功率的激光输出。The multi-stage optical fiber amplifier system provided in this embodiment can multiply the output laser power. Thus, high-power laser output can be realized.
在上述实施例的基础上，所述泵浦反馈装置还用于向所述光纤放大器内输入种子光；On the basis of the above embodiments, the pump feedback device is also used to input seed light into the optical fiber amplifier;
相应地，所述泵浦耦合器还用于输出激光。Correspondingly, the pump coupler is also used to output laser light.
具体地，本实施例中，泵浦反馈装置的一个输入端作为整个光纤放大器的输入端，用于输入种子光。泵浦耦合器、增益光纤和泵浦反馈装置依次连接后，泵浦光通过泵浦耦合器的输入端输入至增益光纤内，增益光纤内的掺杂物质在泵浦光的作用下发生跃迁并弛豫至能量较低的激发态，种子光通过泵浦反馈装置的输入端输入，种子光使得激发态上的粒子产生受激辐射，并跃迁至低能态释放出能量，使种子光得到放大，产生激光。Specifically, in this embodiment, one input end of the pump feedback device is used as the input end of the entire optical fiber amplifier for inputting seed light. After the pump coupler, the gain fiber and the pump feedback device are connected in sequence, the pump light is input into the gain fiber through the input end of the pump coupler, and the dopant in the gain fiber undergoes a transition under the action of the pump light and Relax to an excited state with lower energy, the seed light is input through the input end of the pump feedback device, the seed light causes the particles in the excited state to generate stimulated radiation, and transitions to a low energy state to release energy, so that the seed light is amplified, Generate laser light.
本实施例中，提供了一种后向泵浦光纤放大器，使泵浦光与种子光分别耦合至增益光纤内。这种光纤放大器通过泵浦反馈装置将残余泵浦光反馈至泵浦耦合器的输入端，使残余泵浦光得到重复利用，能充分提高光纤放大器的功率。In this embodiment, a backward-pumped fiber amplifier is provided, so that the pump light and the seed light are respectively coupled into the gain fiber. The optical fiber amplifier feeds back the residual pumping light to the input end of the pumping coupler through the pumping feedback device, so that the residual pumping light can be reused, and the power of the optical fiber amplifier can be fully increased.
如图7所示，在上述实施例的基础上，光纤放大器中可包括：种子装置24和泵浦装置25。种子装置24与泵浦反馈装置23的输入端相连，泵浦装置25与泵浦耦合器21的输入端连接。其中，泵浦装置25可作为光纤放大器的泵浦源，为光纤放大器提供泵浦光。由泵浦装置25发出的泵浦光通过泵浦耦合器21耦合至增益光纤22，激发增益光纤22内的掺杂离子。种子装置24作为光纤放大器的种子源，为光纤放大器提供种子光。由种子装置24发出的种子光经过泵浦反馈装置23注耦合至增益光纤22中进行泵浦抽运放大。并通过泵浦耦合器的输出端输出放大后得到的激光。As shown in FIG. 7 , on the basis of the above embodiments, the optical fiber amplifier may include: a seed device 24 and a pump device 25 . The seed device 24 is connected to the input end of the pump feedback device 23 , and the pump device 25 is connected to the input end of the pump coupler 21 . Wherein, the pumping device 25 can be used as a pumping source of the optical fiber amplifier to provide pumping light for the optical fiber amplifier. The pump light emitted by the pump device 25 is coupled to the gain fiber 22 through the pump coupler 21 to excite dopant ions in the gain fiber 22 . The seed device 24 is used as a seed source of the optical fiber amplifier to provide seed light for the optical fiber amplifier. The seed light emitted by the seed device 24 is coupled to the gain fiber 22 through the pump feedback device 23 for pumping and pumping amplification. And output the amplified laser light through the output end of the pump coupler.
本实施例中，通过设置种子装置和泵浦装置，可以使光纤放大器持续工作，不间断的产生高功率的激光。In this embodiment, by setting the seed device and the pumping device, the optical fiber amplifier can be continuously operated to generate high-power laser light without interruption.
在上述实施例的基础上，所述泵浦反馈装置具体包括：具有2个输入端和M个输出端的分束器，其中M为大于或等于1的整数；On the basis of the above embodiments, the pump feedback device specifically includes: a beam splitter with 2 input terminals and M output terminals, where M is an integer greater than or equal to 1;
所述分束器的一个输入端用于输入种子光，所述分束器的另一个输入端与所述增益光纤的一端连接，所述分束器的另一个输入端用于将所述种子光输出至所述增益光纤，还用于接收所述增益光纤内的残余泵浦光；One input end of the beam splitter is used to input seed light, the other input end of the beam splitter is connected to one end of the gain fiber, and the other input end of the beam splitter is used to input the seed light Light is output to the gain fiber and is also used to receive residual pump light in the gain fiber;
所述分束器的M个输出端中每一个输出端均与所述泵浦耦合器的一个输入端连接。Each of the M output terminals of the beam splitter is connected to an input terminal of the pump coupler.
具体地，如图8所示，图8中以泵浦耦合器21的输入端连接有六个泵浦装置为例。采用六个泵浦装置是为保证向增益光纤提供充足的泵浦光，但本发明并不具体限定泵浦装置的数量。图8中M＝1，分束器231具有两个输入端，一个输入端与种子装置连接，用于输入种子光，另一个输入端与所述增益光纤的一端连接。分束器231具有1个输出端，分束器231的输出端与泵浦耦合器21的输入端连接。泵浦耦合器21的一个输出端与增益光纤22的一端连接，另一个输出端用于输出激光。Specifically, as shown in FIG. 8 , an example in which six pump devices are connected to the input end of the pump coupler 21 is used in FIG. 8 . The use of six pumping devices is to ensure sufficient pumping light for the gain fiber, but the present invention does not specifically limit the number of pumping devices. M=1 in FIG. 8 , the beam splitter 231 has two input ends, one input end is connected to the seed device for inputting seed light, and the other input end is connected to one end of the gain fiber. The beam splitter 231 has one output end, and the output end of the beam splitter 231 is connected to the input end of the pump coupler 21 . One output end of the pump coupler 21 is connected to one end of the gain fiber 22, and the other output end is used for outputting laser light.
本实施例中，设置了多个泵浦装置，为光纤放大器提供了充足的泵浦光。同时，还将分束器的输出端与泵浦耦合器的输入端连接，使增益光纤内产生的残余泵浦光可以经泵浦耦合器的输入端，再次进入增益光纤，以达到重复利用的目的，进而节约了资源。In this embodiment, multiple pumping devices are provided to provide sufficient pumping light for the fiber amplifier. At the same time, the output end of the beam splitter is connected to the input end of the pump coupler, so that the residual pump light generated in the gain fiber can enter the gain fiber again through the input end of the pump coupler, so as to achieve the purpose of repeated use. purpose, thereby saving resources.
在上述实施例的基础上，当M>1时，所述泵浦反馈装置还包括：n个合束器，每个合束器具有N个输入端和一个输出端，其中n为不小于1的整数，n*N＝M；On the basis of the above-mentioned embodiments, when M>1, the pumping feedback device further includes: n beam combiners, each beam combiner has N input terminals and one output terminal, wherein n is not less than 1 An integer of n*N=M;
所述n个合束器中的每一个输入端均与所述分束器的一个输出端连接，所述n个合束器中的每一个输出端均与所述泵浦耦合器的一个输入端连接。Each input end of the n beam combiners is connected to an output end of the beam splitter, and each output end of the n beam combiners is connected to an input of the pump coupler end connection.
具体地，如图9所示，以具有2个输入端和6个输出端的分束器作为泵浦反馈装置23，图9中共有2个合束器，每个合束器具有3个输入端和一个输出端，即M＝6，n＝2，N＝3。其中，分束器231的6个输出端分上下各3个，上面3个输出端中每一个与合束器232的一个输入端连接，该合束器232的输出端与泵浦耦合器21的一个输入端连接。下面3个输出端中每一个与合束器233的一个输入端连接，该合束器233的输出端也与泵浦耦合器21的一个输入端连接。Specifically, as shown in FIG. 9, a beam splitter with 2 input terminals and 6 output terminals is used as the pumping feedback device 23. There are 2 beam combiners in FIG. 9, and each beam combiner has 3 input terminals. and one output, ie M=6, n=2, N=3. Wherein, the 6 output ends of the beam splitter 231 are divided into three upper and lower ones, and each of the upper three output ends is connected to an input end of the beam combiner 232, and the output end of the beam combiner 232 is connected to the pump coupler 21 One of the input connections. Each of the lower three outputs is connected to an input of a beam combiner 233 whose output is also connected to an input of the pump coupler 21 .
需要说明的是，本发明并不具体限定分束器或合束器输入端或输出端的数量。但是使用输出端更多的分束器可以使增益光纤内的残余泵浦光被更充分的分离并利用。It should be noted that the present invention does not specifically limit the number of input ports or output ports of the beam splitter or the beam combiner. But using more beam splitters at the output can make the residual pump light in the gain fiber be more fully separated and utilized.
在上述实施例的基础上，所述分束器的输入端与所述增益光纤的一端之间还可设置有锥形适配器；On the basis of the above embodiments, a tapered adapter may also be provided between the input end of the beam splitter and one end of the gain fiber;
所述锥形适配器第一端的光纤横截面积小于第二端的光纤横截面积，所述锥形适配器的第一端与所述增益光纤的一端连接，所述锥形适配器的第二端与所述分束器的输入端连接。The optical fiber cross-sectional area of the first end of the tapered adapter is smaller than the optical fiber cross-sectional area of the second end, the first end of the tapered adapter is connected to one end of the gain fiber, and the second end of the tapered adapter is connected to The input of the beam splitter is connected.
具体地，由于残余泵浦光大部分位于增益光纤的包层区域，所以增加包层区域占整个光纤端面的比例，可提升残余泵浦光的反馈效率，从而提高光纤放大器的效率。所以本实施例中增加了锥形适配器，使增益光纤的纤芯保持大小不变，将增益光纤的端面面积整体增加，将小口径的增益光纤转化至大口径的光纤，此时端面中包层区域所占比例将增加，大口径的光纤再与分束器的输入端连接。Specifically, since most of the residual pump light is located in the cladding region of the gain fiber, increasing the ratio of the cladding region to the entire fiber end face can improve the feedback efficiency of the residual pump light, thereby improving the efficiency of the fiber amplifier. Therefore, in this embodiment, a tapered adapter is added to keep the core size of the gain fiber unchanged, increase the overall area of the end face of the gain fiber, and convert the small-diameter gain fiber into a large-diameter fiber. At this time, the cladding in the end face The proportion of the area will increase, and the large-caliber optical fiber will be connected to the input end of the beam splitter.
本发明另一实施例提供了一种多级光纤放大器系统，包括至少两个依次设置的、如上述实施例所述的后向泵浦光纤放大器。Another embodiment of the present invention provides a multi-stage optical fiber amplifier system, including at least two backward-pumped optical fiber amplifiers arranged in sequence as described in the above-mentioned embodiments.
作为优选方案，多级光纤放大器系统中每相邻的两个光纤放大器，前一个光纤放大器输出的激光为后一个光纤放大器的种子光。As a preferred solution, for every two adjacent fiber amplifiers in the multi-stage fiber amplifier system, the laser output from the previous fiber amplifier is the seed light of the latter fiber amplifier.
具体地，如图10所示，图10中显示的后向泵浦的多级光纤放大器系统中包括三个依次设置的、如上述实施例所述的后向泵浦光纤放大器，其中，第一个光纤放大器作为一级放大，第二个光纤放大器作为二级放大，第三个光纤放大器作为三级放大。第一个光纤放大器的一个输入端连接有种子装置，用于为多级光纤放大器系统提供种子光，第一个光纤放大器用于输出激光的输出端与第二个光纤放大器用于输入种子光的输入端连接，即将一级放大得到的激光作为种子光输入至第二个光纤放大器中进行二级放大，同样地，第二个光纤放大器用于输出激光的输出端与第三个光纤放大器用于输入种子光的输入端连接，即将二级放大得到的激光作为种子光输入至第三个光纤放大器中进行三级放大，最终通过第三个光纤放大器输出经过三级放大的激光。Specifically, as shown in FIG. 10, the backward-pumped multistage optical fiber amplifier system shown in FIG. 10 includes three backward-pumped optical fiber amplifiers arranged in sequence as described in the above-mentioned embodiments, wherein the first The first optical fiber amplifier is used as a first-stage amplification, the second optical fiber amplifier is used as a second-stage amplification, and the third optical fiber amplifier is used as a third-stage amplification. One input end of the first fiber amplifier is connected with a seed device, which is used to provide seed light for the multi-stage fiber amplifier system. The output end of the first fiber amplifier is used to output laser light and the second fiber amplifier is used to input seed light. The input end is connected, that is, the laser light obtained by the primary amplification is input into the second optical fiber amplifier as the seed light for secondary amplification. Similarly, the output end of the second optical fiber amplifier is used to output the laser and the third optical fiber amplifier is used for The input end of the input seed light is connected, that is, the laser light obtained by the secondary amplification is input to the third optical fiber amplifier as the seed light for three-stage amplification, and finally the third-stage amplified laser is output through the third optical fiber amplifier.
本实施例提供的多级光纤放大器系统，可以使输出的激光的功率成倍增加。进而实现高功率的激光输出。The multi-stage optical fiber amplifier system provided in this embodiment can multiply the output laser power. Thus, high-power laser output can be realized.
在上述实施例的基础上，由于光纤放大器是全光纤的，所以光纤放大器中各个光器件之间的连接均可采用光纤熔接进行连接，还可以利用光纤转接口进行连接，本发明在此不做具体限定。On the basis of the above-mentioned embodiments, since the optical fiber amplifier is all optical fiber, the connection between each optical device in the optical fiber amplifier can be connected by optical fiber fusion splicing, and can also be connected by optical fiber conversion interface, which is not discussed in the present invention. Specific limits.
在上述实施例的基础上，光纤放大器内采用的泵浦反馈装置可采用一个45度分束镜和透镜的组合来实现。On the basis of the above embodiments, the pump feedback device used in the fiber amplifier can be realized by a combination of a 45-degree beam splitter and a lens.
具体地，以前向泵浦光纤放大器为例，经增益光纤输出的是一种混合光，具体包括残余泵浦光和激光。经45度分束镜后可将残余泵浦光和激光分离，得到的激光直接输出，得到的残余泵浦光经透镜会聚至泵浦耦合器的输入端。Specifically, taking the forward-pumped fiber amplifier as an example, what is output through the gain fiber is a kind of mixed light, specifically including residual pump light and laser light. After the 45-degree beam splitter, the residual pump light can be separated from the laser, and the obtained laser is output directly, and the obtained residual pump light is converged to the input end of the pump coupler through the lens.
为减小整个光路的长度，还可以在光路中加入平面镜。In order to reduce the length of the entire optical path, a plane mirror can also be added in the optical path.
本实施例中，采用45度分束镜和透镜的组合同样可以实现残余泵浦光的重复利用，为泵浦反馈装置提供了一种新的结构。In this embodiment, the combination of a 45-degree beam splitter and a lens can also realize the reuse of residual pump light, which provides a new structure for the pump feedback device.
在上述实施例的基础上，所述增益光纤可包括：多包层光纤、多芯光纤、保偏光纤等。On the basis of the above embodiments, the gain fiber may include: multi-clad fiber, multi-core fiber, polarization maintaining fiber and the like.
在上述实施例的基础上，所述增益光纤的纤芯中的掺杂物质可以为稀土离子，具体如镱离子、铥离子、铒离子、钬离子或钕离子等。Based on the above embodiments, the dopant in the core of the gain fiber may be rare earth ions, such as ytterbium ions, thulium ions, erbium ions, holmium ions, or neodymium ions.
本发明提供的光纤放大器，通过缩短光纤放大器中增益光纤的长度，有效地抑制了非线性效应的产生，同时较短的增益光纤有效地抑制了增益光纤对于信号光的重吸收。同时，本发明中的泵浦反馈装置实现了提升泵浦效率的优势。此外，本发明提供的多级光纤放大器系统，包含的光纤放大器越多，这种提升泵浦效率的优势越显著，输出的激光的功率越高。本发明提供的光纤放大器，适用于连续的光纤放大器中，亦适用于脉冲光纤放大器中。另外，此结构简单可靠，操作方便，可以广泛适用于各种掺杂光纤激光器中，适用于前向以及后向泵浦的多级光纤放大器系统。The optical fiber amplifier provided by the invention effectively suppresses the occurrence of nonlinear effects by shortening the length of the gain fiber in the fiber amplifier, and meanwhile, the shorter gain fiber effectively suppresses the reabsorption of the signal light by the gain fiber. At the same time, the pumping feedback device in the present invention realizes the advantage of improving the pumping efficiency. In addition, in the multi-stage fiber amplifier system provided by the present invention, the more fiber amplifiers are included, the more significant the advantage of improving the pumping efficiency is, and the higher the output laser power is. The optical fiber amplifier provided by the invention is suitable for continuous optical fiber amplifiers and also for pulse optical fiber amplifiers. In addition, the structure is simple and reliable, and the operation is convenient, and can be widely used in various doped fiber lasers, and is suitable for forward and backward pumped multistage fiber amplifier systems.
最后，本发明的方法仅为较佳的实施方案，并非用于限定本发明的保护范围。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。Finally, the method of the present invention is only a preferred embodiment, and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
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| WO2024188227A1 (en) * | 2023-03-15 | 2024-09-19 | 华为技术有限公司 | Optical fiber amplifier, optical power amplification method, related device, and system |
| CN119362123A (en) * | 2024-09-29 | 2025-01-24 | 上海虹剑光电科技有限公司 | A high-efficiency reverse-pumped fiber laser amplifier and amplification method thereof |
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