WO2019090957A1 - Nanosecond pulsed fiber laser device - Google Patents

Nanosecond pulsed fiber laser device Download PDF

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Publication number
WO2019090957A1
WO2019090957A1 PCT/CN2018/071146 CN2018071146W WO2019090957A1 WO 2019090957 A1 WO2019090957 A1 WO 2019090957A1 CN 2018071146 W CN2018071146 W CN 2018071146W WO 2019090957 A1 WO2019090957 A1 WO 2019090957A1
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Prior art keywords
laser
pulsed
stage
fiber
generator
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PCT/CN2018/071146
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French (fr)
Chinese (zh)
Inventor
钟亥哲
杨建龙
胡斌
王世伟
范滇元
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深圳大学
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Publication of WO2019090957A1 publication Critical patent/WO2019090957A1/en

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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
    • 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
    • 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
    • H01S3/0941—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a laser diode
    • 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
    • H01S5/00—Semiconductor lasers
    • H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
    • H01S5/4018—Lasers electrically in series

Definitions

  • the present invention relates to the field of laser technology, and in particular to a nanosecond pulsed fiber laser.
  • Mid-infrared nanosecond pulsed laser has great application prospects in the fields of non-metallic material marking, environmental monitoring, and biological detection.
  • the performance of mid-infrared nanosecond pulsed lasers has been greatly improved.
  • the methods for generating mid-infrared nanosecond pulsed lasers mainly include rare earth ion doped solid or fiber lasers, quantum cascade lasers, and nonlinear frequency conversion.
  • the fiber laser has the advantages of simple structure, compactness, spot quality near the diffraction limit, and high conversion efficiency. Therefore, in recent years, mid-infrared nanosecond pulsed fiber lasers have gained more and more attention.
  • the wavelength of the laser directly obtained by the mid-infrared nanosecond pulsed fiber laser is limited to 3 micrometers and below, and the longer wavelength mid-infrared nanosecond pulsed laser has strong application requirements in many fields.
  • the main object of the present invention is to provide a nanosecond pulsed fiber laser for solving the technical problem that the laser wavelength directly obtained by the nanosecond pulsed fiber laser in the prior art is limited to 3 micrometers and less.
  • the present invention provides a nanosecond pulsed fiber laser comprising: a first stage pulsed laser generator, a second stage pulsed laser generator, a third stage pulsed laser generator, and continuous a laser diode, wherein the first stage pulse laser generator comprises a laser diode, an output end of the first stage pulse laser generator is connected to an input end of the second stage pulse laser generator, and the second stage pulse An output end of the laser generator and the continuous laser diode are respectively connected to one of the input ends of the two input ends of the third-stage pulse laser generator to form a serial cascade structure;
  • the laser diode is configured to generate a 1.55 micron pulsed laser and output from the first stage pulsed laser generator output to the second stage pulsed laser generator as a pump source of the second stage pulsed laser generator ;
  • the second stage pulsed laser generator is configured to generate and output a 1.97 micron pulsed laser to the third stage pulsed laser generator;
  • the third-stage pulsed laser generator is configured to couple the 1.97 micron pulsed laser and the high power continuous laser output of the continuous laser diode as a pump source of the third-stage pulsed laser generator, and generate The 3.47 micron pulsed laser is output.
  • the nanosecond pulsed fiber laser includes a three-stage pulse laser generator in a cascade cascade structure, and therefore, compared with the prior art, the present invention provides
  • the nanosecond pulsed fiber laser has the advantages of compact structure and integration.
  • the three-stage pulsed laser generator generates 1.55 micron pulsed laser, 1.97 micron pulsed laser and 3.47 micron pulsed laser respectively, and realizes the laser wavelength of the pulsed laser from 1.55.
  • the nanosecond pulsed fiber laser provided by the invention can not only output a typical mid-infrared pulse laser of 3.47 micrometer, but also meets the needs of various fields, and only needs the laser two
  • the 1.55 micron pulsed laser generated by the tube can directly generate a 3.47 micron nanosecond pulsed laser as an initial pump source without intermediate conversion. Therefore, the nanosecond pulsed fiber laser provided by the present invention has the advantages of low loss.
  • FIG. 1 is a schematic structural diagram of a nanosecond pulsed fiber laser according to an embodiment of the present invention
  • FIG 2 is an energy level diagram of an Er-doped ZBLAN fiber according to an embodiment of the present invention
  • 3 is a graph showing a variation of pulse width and peak power with time delay of a 3.47 micron pulsed laser according to an embodiment of the present invention
  • FIG. 4 is a graph showing pulse width and peak power of a 3.47 micron pulsed laser under different peak power conditions of pump light according to an embodiment of the present invention.
  • the present invention provides a nanosecond pulsed fiber laser for generating a 3.47 micron nanosecond pulsed laser.
  • the nanosecond pulsed fiber laser includes:
  • One of the input terminals of the input end constitutes a series cascade structure, and the cascade structure makes the nanosecond pulsed fiber laser have the advantages of compact structure and integration;
  • a laser diode 5 for generating a 1.55 micron pulsed laser and outputting from the output of the first stage pulsed laser generator 1 to the second stage pulsed laser generator 2 as a pump source of the second stage pulsed laser generator 2;
  • a second stage pulsed laser generator 2 for generating and outputting a 1.97 micron pulsed laser to the third stage pulsed laser generator 3;
  • the third-stage pulse laser generator 3 is configured to couple the high-power continuous laser output of the 1.97-micron pulse laser and the continuous laser diode 4 as a pump source of the third-stage pulse laser generator 3, and generate and output a 3.47-micron pulse laser. .
  • the laser diode 5 is used to generate a 1.55 micron pulsed laser light and is output from the output end of the first-stage pulsed laser generator 1 to the second-stage pulsed laser generator 2 as a pump source of the second-stage pulsed laser generator 2.
  • the second-stage pulsed laser generator 2 generates and outputs a 1.97-micron pulsed laser light into the third-stage pulsed laser generator 3 due to the input of the pump source.
  • the 1.97 micron pulsed laser and the high power continuous laser output of the continuous laser diode 4 are coupled to the third stage pulsed laser generator 3 as a pump source of the third stage pulsed laser generator 3 to generate and output a 3.47 micron pulsed laser.
  • the nanosecond pulsed fiber laser realizes continuous conversion of the laser wavelength of the pulsed laser from 1.55 micrometers to 1.97 micrometers to 3.47 micrometers. Therefore, the nanosecond pulsed fiber laser provided by the invention can not only output a typical mid-infrared pulsed laser of 3.47 micrometers. It can meet the application requirements of many fields, and only need to use the 1.55 micron pulse laser generated by the laser diode as the initial pump source to directly generate the 3.47 micron nanosecond pulse laser without the conversion of external devices.
  • the nanosecond pulsed fiber laser provided by the invention also has the advantage of low loss.
  • the pulse laser generated by the nanosecond pulse fiber laser is a nanosecond pulse laser
  • the 3.47 micron nanosecond pulse laser belongs to a medium-infrared nanosecond pulse laser
  • the mid-infrared nanosecond pulse laser is in a non-metal. Materials marking, environmental monitoring, biological detection and other fields have great application prospects, so the 3.47 micron nanosecond pulsed laser has great application prospects in these fields.
  • the third-stage pulsed laser generator 3 includes a pumping optical combiner 6 and an Er-doped ZBLAN fiber laser oscillator 7, an output of the second-stage pulsed laser generator 2 and a continuous laser diode. 4 respectively connected to one of the input ends of the pumping light combiner 6 and the pump combiner 6 couples the 1.97 micron pulsed laser with the high power continuous laser and inputs it into the Er-doped ZBLAN fiber laser oscillator 7.
  • the Er-doped ZBLAN fiber laser oscillator 7 produces a 3.47 micron pulsed laser.
  • the pumping optical combiner 6 couples the 1.97 micron pulsed laser with the high power continuous laser and inputs it into the Er-doped ZBLAN fiber laser oscillator 7 as the pump source of the Er-doped ZBLAN fiber laser oscillator 7, Er-doped.
  • the hybrid ZBLAN fiber laser oscillator 7 generates a 3.47 micron pulsed laser to achieve pulse output of the laser.
  • the continuous laser diode 4 is a 975 nm high power continuous laser diode, and the 975 nm high power continuous laser diode produces a 975 nm high power continuous laser.
  • the 975 nm high-power continuous laser and the 1.97-micron pulsed laser are coupled to the Er-doped ZBLAN fiber laser oscillator 7 through the pumping light combiner 6 as a pump source, 975 nm high-power continuous laser and 1.97 ⁇ m pulsed laser.
  • the time delay i.e., the pulse time interval of the 1.97 micron pulsed laser
  • the Er-doped ZBLAN fiber laser oscillator 7 includes an Er-doped ZBLAN fiber 8, a first high-reflection mirror 9 and a first output coupling mirror 10, and the first high-reflection mirror 9 is connected to the Er-doped lens.
  • the first output coupling mirror 10 is connected to the output of the Er-doped ZBLAN fiber laser oscillator 7.
  • Er-doped ZBLAN fiber 8 undergoes energy level transition under the mixed pumping condition of 975 nm high power continuous laser and 1.97 micron pulsed laser, and realizes the output of 3.47 micron pulsed laser.
  • FIG. 2 is an energy level diagram of an Er-doped ZBLAN fiber according to an embodiment of the present invention, and the main energy level transitions under the mixed pumping condition are marked.
  • N 1 to N 7 represent the atomic number density of the 4 I 15/2 level to the 4 F 7/2 level, respectively.
  • W 13 represents the probability of stimulated absorption by 975 nm continuous pump light.
  • W 35 represents the probability of stimulated absorption by 1.97 micron pulsed pump light.
  • W 5 4 represents the rate of stimulated radiation transition from the 4 F 9 /2 level to the 4 I 9 /2 level.
  • W 37 , W 4 7 and W 57 are both excited absorption rates.
  • the process of hybrid pumping is as follows: 975 nm continuous pump light stores pump energy at the 4 I 11/2 level to reduce the oscillation threshold of the pulsed laser. At the same time, the 1.97 micron nanosecond pulsed pump light excites dramatic energy level transitions from the 4 I 11/2 level to the 4 F 9/2 level. Finally, the excitons in the 4 F 9/2 level transition to the low-energy 4 I 9/2 stimulated radiation and produce a 3.47 micron pulsed laser. Since the energy level of the 4 I 9/2 level is much smaller than the 4 I 11/2 level, this process can be considered as a gain switch within the quasi-band.
  • the time delay of the 975 nm high power continuous laser and the 1.97 micron pulsed laser i.e., the pulse time interval of the 1.97 micron pulsed laser
  • the pulse time interval of the 1.97 micron pulsed laser has an important influence on the output of the Er-doped ZBLAN fiber laser oscillator 7.
  • FIG. 3 is a graph showing a variation of pulse width and peak power with time delay of a 3.47 micron pulsed laser according to an embodiment of the present invention.
  • the 1.97 micron pulse pump light has a pulse width of 300 nanoseconds and a peak power of 0.5 kW.
  • a stable laser output can be formed.
  • the pulsed laser becomes stronger and stronger, and then, around approximately 400 microseconds, the fiber laser enters a saturated state.
  • the saturation pulse width is around 190 nanoseconds, corresponding to a peak power of about 93W.
  • FIG. 4 is a graph showing pulse width and peak power of a 3.47 micron pulsed laser under different pump light peak power conditions according to an embodiment of the present invention.
  • the time delay of 1.97 micron pulsed pump light and 975 nanometer continuous pump light is 600 microseconds. It can be seen that when the peak power of the pump light is 0.5 kW, the pulse width of the 3.47 micron pulsed laser is about 200 nanoseconds. As the peak power of the pump light increases, the pulse width will gradually narrow and gradually stabilize around 70 nanoseconds. Unlike the pulse width, the peak power of the 3.47 micron pulsed laser continues to increase with the increase of the peak power of the pump light, although the growth rate becomes slower and slower in the given peak power range.
  • the Er-doped ZBLAN fiber laser oscillator 7 can output a pulse width of at least 70 nanoseconds with a peak current of 1.97 micrometers with a peak power of 0.5 to 2 kW. Second pulse laser.
  • the first-stage pulsed laser generator 1 further includes a pulse signal generator 11, a first optical isolator 12 and a laser amplifier 13, and the pulse signal generator 11 is connected to the laser diode 5, and the pulse signal is generated.
  • the device 11 is for controlling the pulse width and repetition frequency of the 1.55 micron pulsed laser outputted by the laser diode 5.
  • the output end of the laser diode 5 is connected to the input end of the first optical isolator 12, and the output end of the first optical isolator 12 and the laser
  • the input of the amplifier 13 is connected, and the laser amplifier 13 is used to increase the peak power of the 1.55 micron pulsed laser generated by the laser diode 5.
  • the output of the laser amplifier is the output of the first stage pulsed laser generator 1.
  • the pulse width and repetition frequency of the 1.55 micron pulse laser largely determine the 1.97 micron pulse laser output from the second stage pulse laser generator 2. And the pulse width and repetition frequency of the 3.47 micron pulsed laser output from the third-stage pulsed laser generator 3.
  • the pulse width and repetition frequency of the 1.55 micron pulsed laser output from the 1.55 micron laser diode 5 can be directly controlled by the pulse signal generator 11. Based on such a series design, the time between 1.97 micron pulsed pump light and 975 nanometer continuous pump light of Er-doped ZBLAN fiber laser oscillator 7 can be dynamically adjusted by adjusting the pulse width and repetition frequency of the 1.55 micron pulsed laser.
  • the laser amplifier 13 is required to amplify the peak power of the 1.55 micron pulsed laser.
  • the second-stage pulsed laser generator 2 includes: a second optical isolator 14 and a Tm-doped quartz fiber laser oscillator 15, and the input end of the second optical isolator 14 is a second-stage pulse.
  • the input end of the laser generator 2, the output end of the second optical isolator 14 is connected to the input end of the Tm-doped quartz fiber laser oscillator 15, and the peak power 1.55 micron pulsed laser is used as the Tm-doped quartz fiber laser oscillator.
  • a pump source of 15, Tm-doped quartz fiber laser oscillator 15 produces a 1.97 micron pulsed laser.
  • the Tm-doped quartz fiber laser oscillator 15 includes a Tm-doped quartz fiber 16, a second high-reflection mirror 17 and a second output coupling mirror 18, and the second high-reflection mirror 17 is connected to the Tm-doped At the input end of the hetero-silica fiber 16, a second output coupling mirror 18 is connected to the output end of the Tm-doped quartz fiber 16, so that the Tm-doped quartz fiber laser oscillator 15 can oscillate to generate laser light.
  • first optical isolator 12 and the second optical isolator 14 are arranged to avoid the occurrence of parasitic oscillations, and when the laser wavelength is greater than 2.3 micrometers, the transmission loss of the Tm-doped quartz optical fiber increases sharply, and thus the Tm An optical isolator is not required between the doped quartz fiber laser oscillator 15 and the Er-doped ZBLAN fiber laser oscillator 7.
  • first high mirror 9, the first output coupling mirror 10, the second high mirror 17 and the second output coupling mirror 18 are all fiber Bragg gratings, and the first high mirror 9 and the first output coupling are disposed.
  • the mirror 10, the second high mirror 17 and the second output coupling mirror 18 are both fiber Bragg gratings for making the nanosecond pulsed fiber laser easier to prepare, and the first high mirror 9 using the fiber Bragg grating is first.
  • the output coupling mirror 10, the second high mirror 17 and the second output coupling mirror 18 are preferably effective.
  • the laser amplifier 13 is an Er/Yb co-doped fiber laser amplifier for increasing the peak power of the 1.55 micron pulsed laser.
  • the Tm-doped quartz fiber laser oscillator 15 and the Er-doped ZBLAN fiber laser oscillator 7 are connected in series because the Tm-doped quartz fiber laser oscillator 15 and the Er-doped ZBLAN fiber laser oscillator 7 are respectively
  • the important part of the two-stage pulse laser generator 2 and the third-stage pulse laser generator 3 is such that the connection between the second-stage pulsed laser generator 2 and the third-stage pulsed laser generator 3 is also in series, the second stage
  • the connection between the pulsed laser generator 2 and the third-stage pulsed laser generator 3 is an important factor in which the series connection is a three-stage pulsed laser generator.
  • the nanosecond pulsed fiber laser provided by the embodiment of the present invention can be seen that, on the one hand, the three-stage pulsed laser generator included in the nanosecond pulsed fiber laser has a cascade cascade structure, and thus, compared with the prior art,
  • the nanosecond pulsed fiber laser provided by the invention has the advantages of compact structure and integration; on the other hand, the three-stage pulse laser generator respectively generates a 1.55 micron pulse laser, a 1.97 micron pulse laser and a 3.47 micron pulse laser to realize a pulsed laser.
  • the laser wavelength is continuously converted from 1.55 micrometers to 1.97 micrometers to 3.47 micrometers.
  • the nanosecond pulsed fiber laser provided by the invention can not only output a typical mid-infrared pulse laser of 3.47 micrometers, but also meets the needs of various fields, and only needs to
  • the 1.55 micron pulsed laser generated by the laser diode can directly generate a 3.47 micron nanosecond pulsed laser as an initial pump source without intermediate device conversion. Therefore, the nanosecond pulsed fiber laser provided by the invention also has a loss. Low advantage.

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  • Optics & Photonics (AREA)
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Abstract

A nanosecond pulsed fiber laser device, comprising a first stage pulsed laser generator (1), a second stage pulsed laser generator (2), a third stage pulsed laser generator (3) and a continuous laser diode (4), the first stage pulsed laser generator (1) comprising a laser diode (5); an output end of the first stage pulsed laser generator (1) is connected to an input end of the second stage pulsed laser generator (2); an output end of the second stage pulsed laser generator (2) and the continuous laser diode (4) are respectively connected to one of two input ends of the third stage pulsed laser generator (3); and the first stage pulsed laser generator (1), the second stage pulsed laser generator (2) and the third stage pulsed laser generator (3) form a series cascade structure. A 1.55-micron pulsed laser generated by the laser diode (5) is used as an initial pumping source, enabling the direct generation of a 3.47-micron nanosecond pulsed laser. The nanosecond pulsed fiber laser device has advantages of low loss, compactness and integration.

Description

一种纳秒脉冲光纤激光器Nanosecond pulsed fiber laser
本发明涉及激光技术领域，尤其涉及一种纳秒脉冲光纤激光器。The present invention relates to the field of laser technology, and in particular to a nanosecond pulsed fiber laser.
中红外纳秒脉冲激光在非金属材料打标、环境监测、生物探测等领域有极大的应用前景。近年来，伴随着激光材料、泵浦技术和光学元器件的发展，中红外纳秒脉冲激光的性能得到长足的进步。目前，产生中红外纳秒脉冲激光的方法主要包括稀土离子掺杂的固体或者光纤激光器，量子级联激光器，非线性频率转换等。其中，光纤激光器有着结构简单，紧凑，近衍射极限的光斑质量以及高转换效率等优点。因此，近年来，中红外纳秒脉冲光纤激光器赢得了越来越多的关注。Mid-infrared nanosecond pulsed laser has great application prospects in the fields of non-metallic material marking, environmental monitoring, and biological detection. In recent years, along with the development of laser materials, pumping technology and optical components, the performance of mid-infrared nanosecond pulsed lasers has been greatly improved. At present, the methods for generating mid-infrared nanosecond pulsed lasers mainly include rare earth ion doped solid or fiber lasers, quantum cascade lasers, and nonlinear frequency conversion. Among them, the fiber laser has the advantages of simple structure, compactness, spot quality near the diffraction limit, and high conversion efficiency. Therefore, in recent years, mid-infrared nanosecond pulsed fiber lasers have gained more and more attention.
现有技术中，由中红外纳秒脉冲光纤激光器直接得到的激光波长多限制在3微米及3微米以下，更长波长的中红外纳秒脉冲激光在多领域有着强烈的应用需求。In the prior art, the wavelength of the laser directly obtained by the mid-infrared nanosecond pulsed fiber laser is limited to 3 micrometers and below, and the longer wavelength mid-infrared nanosecond pulsed laser has strong application requirements in many fields.
发明内容Summary of the invention
本发明的主要目的在于提供一种纳秒脉冲光纤激光器，用于解决现有技术中纳秒脉冲光纤激光器直接得到的激光波长多限制在3微米及3微米以下的技术问题。The main object of the present invention is to provide a nanosecond pulsed fiber laser for solving the technical problem that the laser wavelength directly obtained by the nanosecond pulsed fiber laser in the prior art is limited to 3 micrometers and less.
为实现上述目的，本发明提供一种纳秒脉冲光纤激光器，所述纳秒脉冲光纤激光器包括：第一级脉冲激光发生器、第二级脉冲激光发生器、第三级脉冲激光发生器和连续激光二极管，所述第一级脉冲激光发生器中包括激光二极管，所述第一级脉冲激光发生器的输出端连接于所述第二级脉冲激光发生器的输入端，所述第二级脉冲激光发生器的输出端和所述连续激光二极管分别连接于所述第三级脉冲激光发生器的两个输入端的其中一个输入端，构成串联式级联结构；To achieve the above object, the present invention provides a nanosecond pulsed fiber laser comprising: a first stage pulsed laser generator, a second stage pulsed laser generator, a third stage pulsed laser generator, and continuous a laser diode, wherein the first stage pulse laser generator comprises a laser diode, an output end of the first stage pulse laser generator is connected to an input end of the second stage pulse laser generator, and the second stage pulse An output end of the laser generator and the continuous laser diode are respectively connected to one of the input ends of the two input ends of the third-stage pulse laser generator to form a serial cascade structure;
所述激光二极管，用于产生1.55微米脉冲激光并从所述第一级脉冲激光发生器输出端输出至所述第二级脉冲激光发生器作为所述第二级脉冲激光发生器的泵浦源；The laser diode is configured to generate a 1.55 micron pulsed laser and output from the first stage pulsed laser generator output to the second stage pulsed laser generator as a pump source of the second stage pulsed laser generator ;
所述第二级脉冲激光发生器，用于产生并输出1.97微米脉冲激光至所述第三级脉冲激光发生器；The second stage pulsed laser generator is configured to generate and output a 1.97 micron pulsed laser to the third stage pulsed laser generator;
所述第三级脉冲激光发生器，用于将所述1.97微米脉冲激光和所述连续激光二极管输出的高功率连续激光耦合后作为所述第三级脉冲激光发生器的泵浦源，产生并输出3.47微米脉冲激光。The third-stage pulsed laser generator is configured to couple the 1.97 micron pulsed laser and the high power continuous laser output of the continuous laser diode as a pump source of the third-stage pulsed laser generator, and generate The 3.47 micron pulsed laser is output.
从上述本发明提供的纳秒脉冲光纤激光器可知，一方面，该纳秒脉冲光纤激光器包括的三级脉冲激光发生器呈串联式级联结构，因此，与现有技术相比，本发明提供的纳秒脉冲光纤激光器具有结构紧凑和一体化的优点；另一方面，三级脉冲激光发生器分别产生1.55微米脉冲激光、1.97微米脉冲激光和3.47微米脉冲激光，实现了脉冲激光的激光波长从1.55微米到1.97微米再到3.47微米的连续转换，因此，本发明提供的纳秒脉冲光纤激光器不仅能输出3.47微米的典型中红外脉冲激光，满足多领域的应用需求，而且只需以其中的激光二级管产生的1.55微米脉冲激光作为初始泵浦源即可直接产生3.47微米的纳秒脉冲激光，中间无需外界装置的转换，因此，本发明提供的纳秒脉冲光纤激光器还具有损耗低的优点。According to the nanosecond pulse fiber laser provided by the present invention, in one aspect, the nanosecond pulsed fiber laser includes a three-stage pulse laser generator in a cascade cascade structure, and therefore, compared with the prior art, the present invention provides The nanosecond pulsed fiber laser has the advantages of compact structure and integration. On the other hand, the three-stage pulsed laser generator generates 1.55 micron pulsed laser, 1.97 micron pulsed laser and 3.47 micron pulsed laser respectively, and realizes the laser wavelength of the pulsed laser from 1.55. The micron to 1.97 micron and then to 3.47 micron continuous conversion, therefore, the nanosecond pulsed fiber laser provided by the invention can not only output a typical mid-infrared pulse laser of 3.47 micrometer, but also meets the needs of various fields, and only needs the laser two The 1.55 micron pulsed laser generated by the tube can directly generate a 3.47 micron nanosecond pulsed laser as an initial pump source without intermediate conversion. Therefore, the nanosecond pulsed fiber laser provided by the present invention has the advantages of low loss.
附图说明DRAWINGS
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and those skilled in the art can obtain other drawings according to these drawings without any creative work.
图1为本发明实施例提供的一种纳秒脉冲光纤激光器的结构示意图；1 is a schematic structural diagram of a nanosecond pulsed fiber laser according to an embodiment of the present invention;
图2为本发明实施例提供的Er掺杂ZBLAN光纤的能级图；2 is an energy level diagram of an Er-doped ZBLAN fiber according to an embodiment of the present invention;
图3为本发明实施例提供的3.47微米脉冲激光的脉宽与峰值功率随时间延时的变化曲线；3 is a graph showing a variation of pulse width and peak power with time delay of a 3.47 micron pulsed laser according to an embodiment of the present invention;
图4为本发明实施例提供的不同泵浦光峰值功率条件下3.47微米脉冲激光的脉宽与峰值功率的变化曲线。4 is a graph showing pulse width and peak power of a 3.47 micron pulsed laser under different peak power conditions of pump light according to an embodiment of the present invention.
具体实施方式Detailed ways
为使得本发明的发明目的、特征、优点能够更加的明显和易懂，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而非全部实施例。基于本发明中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. The embodiments are merely a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by a person skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.
本发明提出一种纳秒脉冲光纤激光器，该纳秒脉冲光纤激光器用于产生3.47微米的纳秒脉冲激光。The present invention provides a nanosecond pulsed fiber laser for generating a 3.47 micron nanosecond pulsed laser.
请参阅图1，为本发明实施例提供的一种纳秒脉冲光纤激光器的结构示意图，该纳秒脉冲光纤激光器包括：1 is a schematic structural diagram of a nanosecond pulsed fiber laser according to an embodiment of the present invention. The nanosecond pulsed fiber laser includes:
第一级脉冲激光发生器1、第二级脉冲激光发生器2、第三级脉冲激光发生器3和连续激光二激光管4，第一级脉冲激光发生器包括激光二极管5，第一级脉冲激光发生器1的输出端连接于第二级脉冲激光发生器2的输入端，第二级脉冲激光发生器2的输出端和连续激光二极管4分别连接于第三级脉冲激光发生器3的两输入端的其中一个输入端，构成串联式级联结构，这一级联结构使得该纳秒脉冲光纤激光器具有结构紧凑和一体化的优点；First stage pulsed laser generator 1, second stage pulsed laser generator 2, third stage pulsed laser generator 3 and continuous laser two laser tube 4, the first stage pulsed laser generator comprises laser diode 5, first stage pulse The output end of the laser generator 1 is connected to the input end of the second stage pulse laser generator 2, and the output end of the second stage pulse laser generator 2 and the continuous laser diode 4 are respectively connected to the two stages of the third stage pulse laser generator 3. One of the input terminals of the input end constitutes a series cascade structure, and the cascade structure makes the nanosecond pulsed fiber laser have the advantages of compact structure and integration;
激光二极管5，用于产生1.55微米脉冲激光并从第一级脉冲激光发生器1输出端输出至第二级脉冲激光发生器2作为第二级脉冲激光发生器2的泵浦源；a laser diode 5 for generating a 1.55 micron pulsed laser and outputting from the output of the first stage pulsed laser generator 1 to the second stage pulsed laser generator 2 as a pump source of the second stage pulsed laser generator 2;
第二级脉冲激光发生器2，用于产生并输出1.97微米脉冲激光至第三级脉冲激光发生器3；a second stage pulsed laser generator 2 for generating and outputting a 1.97 micron pulsed laser to the third stage pulsed laser generator 3;
第三级脉冲激光发生器3，用于将1.97微米脉冲激光和连续激光二极管4输出的高功率连续激光耦合后作为第三级脉冲激光发生器3的泵浦源，产生并输出3.47微米脉冲激光。The third-stage pulse laser generator 3 is configured to couple the high-power continuous laser output of the 1.97-micron pulse laser and the continuous laser diode 4 as a pump source of the third-stage pulse laser generator 3, and generate and output a 3.47-micron pulse laser. .
其中，激光二极管5用于产生1.55微米脉冲激光并从第一级脉冲激光发生器1的输出端输出到第二级脉冲激光发生器2作为第二级脉冲激光发生器2的泵浦源。第二级脉冲激光发生器2，由于泵浦源的输入，产生并输出1.97微米脉冲激光到第三级脉冲激光发生器3中。1.97微米脉冲激光和连续激光二极管4输出的高功率连续激光耦合后输入第三级脉冲激光发生器3作为第三级脉冲激光发生器3的泵浦源，产生并输出3.47微米脉冲激光。该纳秒脉冲光纤激光器实现了脉冲激光的激光波长从1.55微米到1.97微米再到3.47微米的连续转换，因此，本发明提供的纳秒脉冲光纤激光器不仅能输出3.47微米的典型中红外脉冲激光，满足多领域的应用需求，而且只需以其中的激光二级管产生的1.55微米脉冲激光作为初始泵浦源即可直接产生3.47微米的纳秒脉冲激光，中间无需外界装置的转换，因此，本发明提供的纳秒脉冲光纤激光器还具有损耗低的优点。Among them, the laser diode 5 is used to generate a 1.55 micron pulsed laser light and is output from the output end of the first-stage pulsed laser generator 1 to the second-stage pulsed laser generator 2 as a pump source of the second-stage pulsed laser generator 2. The second-stage pulsed laser generator 2 generates and outputs a 1.97-micron pulsed laser light into the third-stage pulsed laser generator 3 due to the input of the pump source. The 1.97 micron pulsed laser and the high power continuous laser output of the continuous laser diode 4 are coupled to the third stage pulsed laser generator 3 as a pump source of the third stage pulsed laser generator 3 to generate and output a 3.47 micron pulsed laser. The nanosecond pulsed fiber laser realizes continuous conversion of the laser wavelength of the pulsed laser from 1.55 micrometers to 1.97 micrometers to 3.47 micrometers. Therefore, the nanosecond pulsed fiber laser provided by the invention can not only output a typical mid-infrared pulsed laser of 3.47 micrometers. It can meet the application requirements of many fields, and only need to use the 1.55 micron pulse laser generated by the laser diode as the initial pump source to directly generate the 3.47 micron nanosecond pulse laser without the conversion of external devices. The nanosecond pulsed fiber laser provided by the invention also has the advantage of low loss.
需要说明的是，该纳秒脉冲光纤激光器所产生的脉冲激光都是纳秒脉冲激光，3.47微米的纳秒脉冲激光属于中红外纳秒脉冲激光的一种，中红外纳秒脉冲激光在非金属材料打标、环境监测、生物探测等领域有极大的应用前景，因此3.47微米的纳秒脉冲激光在这些领域有极大应用前景。It should be noted that the pulse laser generated by the nanosecond pulse fiber laser is a nanosecond pulse laser, and the 3.47 micron nanosecond pulse laser belongs to a medium-infrared nanosecond pulse laser, and the mid-infrared nanosecond pulse laser is in a non-metal. Materials marking, environmental monitoring, biological detection and other fields have great application prospects, so the 3.47 micron nanosecond pulsed laser has great application prospects in these fields.
进一步的，如图1所示，第三级脉冲激光发生器3包括泵浦光合束器6和Er掺杂ZBLAN光纤激光振荡器7，第二级脉冲激光发生器2的输出端与连续激光二极管4分别连接泵浦光合束器6的两输入端的其中一个输入端，泵浦合束器6将1.97微米脉冲激光与高功率连续激光耦合在一起输入到Er掺杂ZBLAN光纤激光振荡器7中，Er掺杂ZBLAN光纤激光振荡器7产生3.47微米脉冲激光。Further, as shown in FIG. 1, the third-stage pulsed laser generator 3 includes a pumping optical combiner 6 and an Er-doped ZBLAN fiber laser oscillator 7, an output of the second-stage pulsed laser generator 2 and a continuous laser diode. 4 respectively connected to one of the input ends of the pumping light combiner 6 and the pump combiner 6 couples the 1.97 micron pulsed laser with the high power continuous laser and inputs it into the Er-doped ZBLAN fiber laser oscillator 7. The Er-doped ZBLAN fiber laser oscillator 7 produces a 3.47 micron pulsed laser.
其中，泵浦光合束器6将1.97微米脉冲激光与高功率连续激光耦合在一起输入到Er掺杂ZBLAN光纤激光振荡器7中作为Er掺杂ZBLAN光纤激光振荡器7的泵浦源，Er掺杂ZBLAN光纤激光振荡器7产生3.47微米脉冲激光，实现激光的脉冲输出。The pumping optical combiner 6 couples the 1.97 micron pulsed laser with the high power continuous laser and inputs it into the Er-doped ZBLAN fiber laser oscillator 7 as the pump source of the Er-doped ZBLAN fiber laser oscillator 7, Er-doped. The hybrid ZBLAN fiber laser oscillator 7 generates a 3.47 micron pulsed laser to achieve pulse output of the laser.
进一步的，连续激光二极管4为975纳米高功率连续激光二极管，该975纳米高功率连续激光二极管产生975纳米高功率连续激光。Further, the continuous laser diode 4 is a 975 nm high power continuous laser diode, and the 975 nm high power continuous laser diode produces a 975 nm high power continuous laser.
其中，975纳米高功率连续激光和1.97微米脉冲激光经过泵浦光合束器6耦合作为泵浦源输入到Er掺杂ZBLAN光纤激光振荡器7中，975纳米高功率连续激光和1.97微米脉冲激光的时间延时（即1.97微米脉冲激光的脉冲时间间隔）对Er掺杂ZBLAN光纤激光振荡器7的输出结果有重要影响。Among them, the 975 nm high-power continuous laser and the 1.97-micron pulsed laser are coupled to the Er-doped ZBLAN fiber laser oscillator 7 through the pumping light combiner 6 as a pump source, 975 nm high-power continuous laser and 1.97 μm pulsed laser. The time delay (i.e., the pulse time interval of the 1.97 micron pulsed laser) has an important influence on the output of the Er-doped ZBLAN fiber laser oscillator 7.
进一步的，如图1所示，Er掺杂ZBLAN光纤激光振荡器7包括Er掺杂ZBLAN光纤8、第一高反镜9和第一输出耦合镜10，第一高反镜9连接在Er掺杂ZBLAN光纤激光振荡器7的输入端，第一输出耦合镜10连接在Er掺杂ZBLAN光纤激光振荡器7的输出端。Further, as shown in FIG. 1, the Er-doped ZBLAN fiber laser oscillator 7 includes an Er-doped ZBLAN fiber 8, a first high-reflection mirror 9 and a first output coupling mirror 10, and the first high-reflection mirror 9 is connected to the Er-doped lens. At the input of the hybrid ZBLAN fiber laser oscillator 7, the first output coupling mirror 10 is connected to the output of the Er-doped ZBLAN fiber laser oscillator 7.
其中，Er掺杂ZBLAN光纤8在975纳米高功率连续激光和1.97微米脉冲激光的混合泵浦条件下发生能级跃迁，实现3.47微米脉冲激光的输出。Among them, Er-doped ZBLAN fiber 8 undergoes energy level transition under the mixed pumping condition of 975 nm high power continuous laser and 1.97 micron pulsed laser, and realizes the output of 3.47 micron pulsed laser.
具体的，请参阅图2，图2为本发明实施例提供的Er掺杂ZBLAN光纤的能级图，图中标出了混合泵浦条件下主要的能级跃迁。其中，N1到N7分别表示4 I 15/2能级到4 F 7/2能级的原子数密度。W13表示975纳米连续泵浦光造成的受激吸收几率。W35表示1.97微米脉冲泵浦光造成的受激吸收几率。W5 4表示由4 F 9 /2能级到4 I 9 /2能级的受激辐射跃迁速率。W37、W4 7和W57均为受激态吸收几率。如图2中所示，混合泵浦的过程如下：975纳米连续泵浦光将泵浦能量存储于4 I 11/2能级，以此降低脉冲激光的振荡阈值。与此同时，1.97微米的纳秒脉冲泵浦光激发由4 I 11/2能级到4 F 9/2能级的剧烈的能级跃迁。最后，4 F 9/2能级中的激子向低能级4 I 9/2受激辐射跃迁，并产生3.47微米脉冲激光。由于4 I 9/2能级的能级寿命要远小于4 I 11/2能级，因此，这个过程可看作准带内的增益开关。Specifically, please refer to FIG. 2. FIG. 2 is an energy level diagram of an Er-doped ZBLAN fiber according to an embodiment of the present invention, and the main energy level transitions under the mixed pumping condition are marked. Wherein, N 1 to N 7 represent the atomic number density of the 4 I 15/2 level to the 4 F 7/2 level, respectively. W 13 represents the probability of stimulated absorption by 975 nm continuous pump light. W 35 represents the probability of stimulated absorption by 1.97 micron pulsed pump light. W 5 4 represents the rate of stimulated radiation transition from the 4 F 9 /2 level to the 4 I 9 /2 level. W 37 , W 4 7 and W 57 are both excited absorption rates. As shown in Figure 2, the process of hybrid pumping is as follows: 975 nm continuous pump light stores pump energy at the 4 I 11/2 level to reduce the oscillation threshold of the pulsed laser. At the same time, the 1.97 micron nanosecond pulsed pump light excites dramatic energy level transitions from the 4 I 11/2 level to the 4 F 9/2 level. Finally, the excitons in the 4 F 9/2 level transition to the low-energy 4 I 9/2 stimulated radiation and produce a 3.47 micron pulsed laser. Since the energy level of the 4 I 9/2 level is much smaller than the 4 I 11/2 level, this process can be considered as a gain switch within the quasi-band.
其中，在混合增益开关的过程中，首先需要连续泵浦光在长寿命的4 I 11/2能级积累足够的原子数，然后，再由脉冲泵浦激光激发能级间的受激辐射跃迁。因此，975纳米高功率连续激光和1.97微米脉冲激光的时间延时（即1.97微米脉冲激光的脉冲时间间隔）对Er掺杂ZBLAN光纤激光振荡器7的输出结果有重要影响。Among them, in the process of mixing the gain switch, it is first necessary to continuously pump the light to accumulate a sufficient number of atoms in the long-lived 4 I 11/2 level, and then stimulate the excited radiation transition between the energy levels by the pulse pump laser. . Therefore, the time delay of the 975 nm high power continuous laser and the 1.97 micron pulsed laser (i.e., the pulse time interval of the 1.97 micron pulsed laser) has an important influence on the output of the Er-doped ZBLAN fiber laser oscillator 7.
具体的，如图3所示，图3为为本发明实施例提供的3.47微米脉冲激光的脉宽与峰值功率随时间延时的变化曲线。其中，1.97微米脉冲泵浦光的脉宽为300纳秒，峰值功率为0.5kW，从图3可以看出，当时间延时大于140微秒，可形成稳定的激光输出。随着延时的增加，脉冲激光变得越来越强，随后，在大概400微秒附近，光纤激光器进入饱和状态。饱和脉宽在190纳秒左右，对应约93W的峰值功率。Specifically, as shown in FIG. 3, FIG. 3 is a graph showing a variation of pulse width and peak power with time delay of a 3.47 micron pulsed laser according to an embodiment of the present invention. Among them, the 1.97 micron pulse pump light has a pulse width of 300 nanoseconds and a peak power of 0.5 kW. As can be seen from Fig. 3, when the time delay is greater than 140 microseconds, a stable laser output can be formed. As the delay increases, the pulsed laser becomes stronger and stronger, and then, around approximately 400 microseconds, the fiber laser enters a saturated state. The saturation pulse width is around 190 nanoseconds, corresponding to a peak power of about 93W.
进一步的，如图4所示，图4为为本发明实施例提供的不同泵浦光峰值功率条件下3.47微米脉冲激光的脉宽与峰值功率的变化曲线。其中，1.97微米脉冲泵浦光与975纳米连续泵浦光的时间延时为600微秒。可见，当泵浦光峰值功率为0.5kW，3.47微米脉冲激光的脉宽为200纳秒左右。随着泵浦光峰值功率的逐渐增加，脉宽会不断变窄，逐渐稳定在70纳秒附近。与脉宽不同，在给出的峰值功率范围内，虽然增长速率变得越来越缓慢，3.47微米脉冲激光的峰值功率依然会随泵浦光峰值功率的增加持续增长。Further, as shown in FIG. 4, FIG. 4 is a graph showing pulse width and peak power of a 3.47 micron pulsed laser under different pump light peak power conditions according to an embodiment of the present invention. Among them, the time delay of 1.97 micron pulsed pump light and 975 nanometer continuous pump light is 600 microseconds. It can be seen that when the peak power of the pump light is 0.5 kW, the pulse width of the 3.47 micron pulsed laser is about 200 nanoseconds. As the peak power of the pump light increases, the pulse width will gradually narrow and gradually stabilize around 70 nanoseconds. Unlike the pulse width, the peak power of the 3.47 micron pulsed laser continues to increase with the increase of the peak power of the pump light, although the growth rate becomes slower and slower in the given peak power range.
基于上述的结果，利用300纳秒，峰值功率0.5至2kW的1.97微米脉冲激光，Er掺杂ZBLAN光纤激光振荡器7可输出脉宽最短70纳秒，对应峰值功率超过0.9kW的3.47微米的纳秒脉冲激光。Based on the above results, the Er-doped ZBLAN fiber laser oscillator 7 can output a pulse width of at least 70 nanoseconds with a peak current of 1.97 micrometers with a peak power of 0.5 to 2 kW. Second pulse laser.
进一步的，如图1所示，第一级脉冲激光发生器1还包括脉冲信号发生器11、第一光隔离器12和激光放大器13，脉冲信号发生器11与激光二极管5连接，脉冲信号发生器11用于控制激光二极管5输出的1.55微米脉冲激光的脉宽和重复频率，激光二极管5的输出端与第一光隔离器12的输入端连接，第一光隔离器12的输出端与激光放大器13的输入端连接，激光放大器13用于提高激光二极管5产生的1.55微米脉冲激光的峰值功率，激光放大器的输出端为第一级脉冲激光发生器1的输出端。Further, as shown in FIG. 1, the first-stage pulsed laser generator 1 further includes a pulse signal generator 11, a first optical isolator 12 and a laser amplifier 13, and the pulse signal generator 11 is connected to the laser diode 5, and the pulse signal is generated. The device 11 is for controlling the pulse width and repetition frequency of the 1.55 micron pulsed laser outputted by the laser diode 5. The output end of the laser diode 5 is connected to the input end of the first optical isolator 12, and the output end of the first optical isolator 12 and the laser The input of the amplifier 13 is connected, and the laser amplifier 13 is used to increase the peak power of the 1.55 micron pulsed laser generated by the laser diode 5. The output of the laser amplifier is the output of the first stage pulsed laser generator 1.
其中，一方面，由于该纳秒脉冲光纤激光器采用串联式增益开关设计，1.55微米的脉冲激光的脉宽和重复频率很大程度上决定了第二级脉冲激光发生器2输出的1.97微米脉冲激光，以及第三级脉冲激光发生器3输出的3.47微米脉冲激光的脉宽和重复频率。1.55微米激光二极管5输出的1.55微米脉冲激光的脉宽和重复频率可通过脉冲信号发生器11直接控制。基于这样的串联式设计，可通过调整1.55微米脉冲激光的脉宽与重复频率，动态调控Er掺杂ZBLAN光纤激光振荡器7的1.97微米脉冲泵浦光与975纳米连续泵浦光之间的时间延时，达到优化3.47微米脉冲激光输出的目的。另一方面，由于激光二极管5直接得到的1.55微米脉冲激光的峰值功率非常有限，需借助激光放大器13来放大1.55微米脉冲激光的峰值功率。Among them, on the one hand, since the nanosecond pulsed fiber laser adopts a series gain switch design, the pulse width and repetition frequency of the 1.55 micron pulse laser largely determine the 1.97 micron pulse laser output from the second stage pulse laser generator 2. And the pulse width and repetition frequency of the 3.47 micron pulsed laser output from the third-stage pulsed laser generator 3. The pulse width and repetition frequency of the 1.55 micron pulsed laser output from the 1.55 micron laser diode 5 can be directly controlled by the pulse signal generator 11. Based on such a series design, the time between 1.97 micron pulsed pump light and 975 nanometer continuous pump light of Er-doped ZBLAN fiber laser oscillator 7 can be dynamically adjusted by adjusting the pulse width and repetition frequency of the 1.55 micron pulsed laser. Delay, to achieve the purpose of optimizing the 3.47 micron pulsed laser output. On the other hand, since the peak power of the 1.55 micron pulsed laser directly obtained by the laser diode 5 is very limited, the laser amplifier 13 is required to amplify the peak power of the 1.55 micron pulsed laser.
进一步的，如图1所示，第二级脉冲激光发生器2包括：第二光隔离器14和Tm掺杂石英光纤激光振荡器15，第二光隔离器14的输入端为第二级脉冲激光发生器2的输入端，第二光隔离器14的输出端与Tm掺杂石英光纤激光振荡器15的输入端连接，已提高峰值功率的1.55微米脉冲激光作为Tm掺杂石英光纤激光振荡器15的泵浦源，Tm掺杂石英光纤激光振荡器15产生1.97微米脉冲激光。Further, as shown in FIG. 1, the second-stage pulsed laser generator 2 includes: a second optical isolator 14 and a Tm-doped quartz fiber laser oscillator 15, and the input end of the second optical isolator 14 is a second-stage pulse. The input end of the laser generator 2, the output end of the second optical isolator 14 is connected to the input end of the Tm-doped quartz fiber laser oscillator 15, and the peak power 1.55 micron pulsed laser is used as the Tm-doped quartz fiber laser oscillator. A pump source of 15, Tm-doped quartz fiber laser oscillator 15 produces a 1.97 micron pulsed laser.
进一步的，如图1所示，Tm掺杂石英光纤激光振荡器15包括Tm掺杂石英光纤16、第二高反镜17和第二输出耦合镜18，第二高反镜17连接在Tm掺杂石英光纤16的输入端，第二输出耦合镜18连接在Tm掺杂石英光纤16的输出端，使Tm掺杂石英光纤激光振荡器15能够发生振荡产生激光。Further, as shown in FIG. 1, the Tm-doped quartz fiber laser oscillator 15 includes a Tm-doped quartz fiber 16, a second high-reflection mirror 17 and a second output coupling mirror 18, and the second high-reflection mirror 17 is connected to the Tm-doped At the input end of the hetero-silica fiber 16, a second output coupling mirror 18 is connected to the output end of the Tm-doped quartz fiber 16, so that the Tm-doped quartz fiber laser oscillator 15 can oscillate to generate laser light.
需要说明的是，第一光隔离器12和第二光隔离器14的设置是为了避免寄生振荡的出现，而当激光波长大于2.3微米，Tm掺杂石英光纤的传输损耗会急剧上升，因而Tm掺杂石英光纤激光振荡器15和Er掺杂ZBLAN光纤激光振荡器7之间不需要加入光隔离器。It should be noted that the first optical isolator 12 and the second optical isolator 14 are arranged to avoid the occurrence of parasitic oscillations, and when the laser wavelength is greater than 2.3 micrometers, the transmission loss of the Tm-doped quartz optical fiber increases sharply, and thus the Tm An optical isolator is not required between the doped quartz fiber laser oscillator 15 and the Er-doped ZBLAN fiber laser oscillator 7.
进一步的，第一高反镜9、第一输出耦合镜10、第二高反镜17和第二输出耦合镜18均为光纤布拉格Bragg光栅，设置的第一高反镜9、第一输出耦合镜10、第二高反镜17和第二输出耦合镜18均为光纤布拉格Bragg光栅是为了使该纳秒脉冲光纤激光器更易制备，且使用光纤布拉格Bragg光栅的第一高反镜9、第一输出耦合镜10、第二高反镜17和第二输出耦合镜18的效果较佳。Further, the first high mirror 9, the first output coupling mirror 10, the second high mirror 17 and the second output coupling mirror 18 are all fiber Bragg gratings, and the first high mirror 9 and the first output coupling are disposed. The mirror 10, the second high mirror 17 and the second output coupling mirror 18 are both fiber Bragg gratings for making the nanosecond pulsed fiber laser easier to prepare, and the first high mirror 9 using the fiber Bragg grating is first. The output coupling mirror 10, the second high mirror 17 and the second output coupling mirror 18 are preferably effective.
进一步的，激光放大器13为Er/Yb共掺光纤激光放大器，该Er/Yb共掺光纤激光放大器用于提高1.55微米脉冲激光的峰值功率。Further, the laser amplifier 13 is an Er/Yb co-doped fiber laser amplifier for increasing the peak power of the 1.55 micron pulsed laser.
进一步的，Tm掺杂石英光纤激光振荡器15和Er掺杂ZBLAN光纤激光振荡器7连接方式为串联，因为Tm掺杂石英光纤激光振荡器15和Er掺杂ZBLAN光纤激光振荡器7分别是第二级脉冲激光发生器2和第三级脉冲激光发生器3的重要部分，使第二级脉冲激光发生器2和第三级脉冲激光发生器3之间的连接方式也为串联，第二级脉冲激光发生器2和第三级脉冲激光发生器3之间的连接方式为串联是三级脉冲激光发生器构成级联结构的重要因素。Further, the Tm-doped quartz fiber laser oscillator 15 and the Er-doped ZBLAN fiber laser oscillator 7 are connected in series because the Tm-doped quartz fiber laser oscillator 15 and the Er-doped ZBLAN fiber laser oscillator 7 are respectively The important part of the two-stage pulse laser generator 2 and the third-stage pulse laser generator 3 is such that the connection between the second-stage pulsed laser generator 2 and the third-stage pulsed laser generator 3 is also in series, the second stage The connection between the pulsed laser generator 2 and the third-stage pulsed laser generator 3 is an important factor in which the series connection is a three-stage pulsed laser generator.
由附图1本发明实施例提供的纳秒脉冲光纤激光器可知，一方面，该纳秒脉冲光纤激光器包括的三级脉冲激光发生器呈串联式级联结构，因此，与现有技术相比，本发明提供的纳秒脉冲光纤激光器具有结构紧凑和一体化的优点；另一方面，三级脉冲激光发生器分别产生1.55微米脉冲激光、1.97微米脉冲激光和3.47微米脉冲激光，实现了脉冲激光的激光波长从1.55微米到1.97微米再到3.47微米的连续转换，因此，本发明提供的纳秒脉冲光纤激光器不仅能输出3.47微米的典型中红外脉冲激光，满足多领域的应用需求，而且只需以其中的激光二级管产生的1.55微米脉冲激光作为初始泵浦源即可直接产生3.47微米的纳秒脉冲激光，中间无需外界装置的转换，因此，本发明提供的纳秒脉冲光纤激光器还具有损耗低的优点。As shown in FIG. 1 , the nanosecond pulsed fiber laser provided by the embodiment of the present invention can be seen that, on the one hand, the three-stage pulsed laser generator included in the nanosecond pulsed fiber laser has a cascade cascade structure, and thus, compared with the prior art, The nanosecond pulsed fiber laser provided by the invention has the advantages of compact structure and integration; on the other hand, the three-stage pulse laser generator respectively generates a 1.55 micron pulse laser, a 1.97 micron pulse laser and a 3.47 micron pulse laser to realize a pulsed laser. The laser wavelength is continuously converted from 1.55 micrometers to 1.97 micrometers to 3.47 micrometers. Therefore, the nanosecond pulsed fiber laser provided by the invention can not only output a typical mid-infrared pulse laser of 3.47 micrometers, but also meets the needs of various fields, and only needs to The 1.55 micron pulsed laser generated by the laser diode can directly generate a 3.47 micron nanosecond pulsed laser as an initial pump source without intermediate device conversion. Therefore, the nanosecond pulsed fiber laser provided by the invention also has a loss. Low advantage.
以上为对本发明所提供的一种纳秒脉冲光纤激光器的描述，对于本领域的技术人员，依据本发明实施例的思想，在具体实施方式及应用范围上均会有改变之处，综上，本说明书内容不应理解为对本发明的限制。The above is a description of a nanosecond pulsed fiber laser provided by the present invention. For those skilled in the art, according to the idea of the embodiment of the present invention, there will be changes in specific implementation modes and application scopes. The contents of this specification are not to be construed as limiting the invention.

Claims (10)

  1. 一种纳秒脉冲光纤激光器，其特征在于，所述纳秒脉冲光纤激光器包括：第一级脉冲激光发生器、第二级脉冲激光发生器、第三级脉冲激光发生器和连续激光二极管，所述第一级脉冲激光发生器中包括激光二极管，所述第一级脉冲激光发生器的输出端连接于所述第二级脉冲激光发生器的输入端，所述第二级脉冲激光发生器的输出端和所述连续激光二极管分别连接于所述第三级脉冲激光发生器的两个输入端的其中一个输入端，构成串联式级联结构；
    所述激光二极管，用于产生1.55微米脉冲激光并从所述第一级脉冲激光发生器输出端输出至所述第二级脉冲激光发生器作为所述第二级脉冲激光发生器的泵浦源；
    所述第二级脉冲激光发生器，用于产生并输出1.97微米脉冲激光至所述第三级脉冲激光发生器；
    所述第三级脉冲激光发生器，用于将所述1.97微米脉冲激光和所述连续激光二极管输出的高功率连续激光耦合后作为所述第三级脉冲激光发生器的泵浦源，产生并输出3.47微米脉冲激光。    A nanosecond pulsed fiber laser, comprising: a first-stage pulsed laser generator, a second-stage pulsed laser generator, a third-stage pulsed laser generator, and a continuous laser diode; The first stage pulse laser generator includes a laser diode, and an output end of the first stage pulse laser generator is connected to an input end of the second stage pulse laser generator, and the second stage pulse laser generator The output end and the continuous laser diode are respectively connected to one of the input ends of the two input ends of the third-stage pulse laser generator to form a serial cascade structure;
    The laser diode is configured to generate a 1.55 micron pulsed laser and output from the first stage pulsed laser generator output to the second stage pulsed laser generator as a pump source of the second stage pulsed laser generator ;
    The second stage pulsed laser generator is configured to generate and output a 1.97 micron pulsed laser to the third stage pulsed laser generator;
    The third-stage pulsed laser generator is configured to couple the 1.97 micron pulsed laser and the high power continuous laser output of the continuous laser diode as a pump source of the third-stage pulsed laser generator, and generate The 3.47 micron pulsed laser is output.
  2. 根据权利要求1所述的纳秒脉冲光纤激光器，其特征在于，所述第三级脉冲激光发生器包括泵浦光合束器和Er掺杂氟化物ZBLAN光纤激光振荡器；
    所述第二级脉冲激光发生器的输出端与所述连续激光二极管分别连接所述泵浦光合束器的两输入端中的其中一个输入端，所述泵浦光合束器的输出端与所述Er掺杂ZBLAN光纤激光振荡器的输入端连接，所述泵浦光合束器将所述1.97微米脉冲激光与所述高功率连续激光耦合在一起输入到所述Er掺杂ZBLAN光纤激光振荡器中，所述Er掺杂ZBLAN光纤激光振荡器产生所述3.47微米脉冲激光。    The nanosecond pulsed fiber laser according to claim 1, wherein said third-stage pulsed laser generator comprises a pumping optical combiner and an Er-doped fluoride ZBLAN fiber laser oscillator;
    An output end of the second-stage pulsed laser generator and the continuous laser diode are respectively connected to one of two input ends of the pumping light combiner, and an output end of the pumping light combiner Connecting the input end of an Er-doped ZBLAN fiber laser oscillator, the pumping optical combiner coupling the 1.97 micron pulsed laser with the high-power continuous laser to the Er-doped ZBLAN fiber laser oscillator The Er-doped ZBLAN fiber laser oscillator produces the 3.47 micron pulsed laser.
  3. 根据权利要求1或2所述的纳秒脉冲光纤激光器，其特征在于，所述连续激光二极管为975纳米高功率连续激光二极管，所述975纳米高功率连续激光二极管产生975纳米高功率连续激光。The nanosecond pulsed fiber laser according to claim 1 or 2, wherein the continuous laser diode is a 975 nm high power continuous laser diode, and the 975 nm high power continuous laser diode generates a 975 nm high power continuous laser.
  4. 根据权利要求2所述的纳秒脉冲光纤激光器，其特征在于，所述Er掺杂ZBLAN光纤激光振荡器包括Er掺杂ZBLAN光纤、第一高反镜和第一输出耦合镜；
    所述第一高反镜连接在所述Er掺杂ZBLAN光纤的输入端，所述第一输出耦合镜连接在所述Er掺杂ZBLAN光纤的输出端。    The nanosecond pulsed fiber laser according to claim 2, wherein the Er-doped ZBLAN fiber laser oscillator comprises an Er-doped ZBLAN fiber, a first high-reflection mirror, and a first output coupling mirror;
    The first high mirror is coupled to an input of the Er-doped ZBLAN fiber, and the first output coupling mirror is coupled to an output of the Er-doped ZBLAN fiber.
  5. 根据权利要求4所述的纳秒脉冲光纤激光器，其特征在于，所述第一级脉冲激光发生器还包括脉冲信号发生器、第一光隔离器和激光放大器；
    所述脉冲信号发生器与所述激光二极管连接，所述脉冲信号发生器用于控制所述激光二极管输出的所述1.55微米脉冲激光的脉宽和重复频率；
    所述激光二极管的输出端与所述第一光隔离器的输入端连接，所述第一光隔离器的输出端与所述激光放大器的输入端连接，所述激光放大器用于提高所述1.55微米脉冲激光的峰值功率，所述激光放大器的输出端为所述第一级脉冲激光发生器的输出端。    The nanosecond pulsed fiber laser according to claim 4, wherein said first stage pulsed laser generator further comprises a pulse signal generator, a first optical isolator and a laser amplifier;
    The pulse signal generator is coupled to the laser diode, and the pulse signal generator is configured to control a pulse width and a repetition frequency of the 1.55 micron pulse laser output by the laser diode;
    An output end of the laser diode is connected to an input end of the first optical isolator, an output end of the first optical isolator is connected to an input end of the laser amplifier, and the laser amplifier is used to increase the 1.55 The peak power of the micron pulsed laser, the output of which is the output of the first stage pulsed laser generator.
  6. 根据权利要求5所述的纳秒脉冲光纤激光器，其特征在于，所述第二级脉冲激光发生器包括：第二光隔离器和Tm掺杂石英光纤激光振荡器；
    所述第二光隔离器输入端为所述第二级脉冲激光发生器的输入端，所述第二光隔离器的输出端与所述Tm掺杂石英光纤激光振荡器的输入端连接，已提高峰值功率的所述1.55微米脉冲激光作为所述Tm掺杂石英光纤激光振荡器的泵浦源，所述Tm掺杂石英光纤激光振荡器产生所述1.97微米脉冲激光。    The nanosecond pulsed fiber laser according to claim 5, wherein the second-stage pulsed laser generator comprises: a second optical isolator and a Tm-doped quartz fiber laser oscillator;
    The second optical isolator input end is an input end of the second-stage pulsed laser generator, and an output end of the second optical isolator is connected to an input end of the Tm-doped quartz fiber laser oscillator The 1.55 micron pulsed laser that increases peak power is used as a pump source for the Tm-doped quartz fiber laser oscillator, which produces the 1.97 micron pulsed laser.
  7. 根据权利要求6所述的纳秒脉冲光纤激光器，其特征在于，所述Tm掺杂石英光纤激光振荡器包括Tm掺杂石英光纤、第二高反镜和第二输出耦合镜，所述第二高反镜连接在所述Tm掺杂石英光纤的输入端，所述第二输出耦合镜连接在所述Tm掺杂石英光纤的输出端。The nanosecond pulsed fiber laser according to claim 6, wherein the Tm-doped quartz fiber laser oscillator comprises a Tm-doped quartz fiber, a second high-reflection mirror, and a second output coupling mirror, the second A high mirror is coupled to the input of the Tm-doped silica fiber, and a second output coupling mirror is coupled to the output of the Tm-doped silica fiber.
  8. 根据权利要求7所述的纳秒脉冲光纤激光器，其特征在于，所述第一高反镜、所述第一输出耦合镜、所述第二高反镜和所述第二输出耦合镜均为光纤布拉格Bragg光栅。The nanosecond pulsed fiber laser according to claim 7, wherein said first high mirror, said first output coupling mirror, said second high mirror and said second output coupling mirror are Fiber Bragg Bragg grating.
  9. 根据权利要求5至8任意一项所述的纳秒脉冲光纤激光器，其特征在于，所述激光放大器为Er/Yb共掺光纤激光放大器。The nanosecond pulsed fiber laser according to any one of claims 5 to 8, wherein the laser amplifier is an Er/Yb co-doped fiber laser amplifier.
  10. 根据权利要求6至8任意一项所述的纳秒脉冲光纤激光器，其特征在于，所述Tm掺杂石英光纤激光振荡器和所述Er掺杂ZBLAN光纤激光振荡器连接方式为串联。The nanosecond pulsed fiber laser according to any one of claims 6 to 8, wherein the Tm-doped quartz fiber laser oscillator and the Er-doped ZBLAN fiber laser oscillator are connected in series.
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