CN216015994U - Laser device - Google Patents

Abstract

The utility model discloses a laser, comprising: a seed source for outputting initial laser, a first-stage amplifier for preventing amplification, a second-stage amplifier for second amplification and a third-stage amplifier for third amplification, which are sequentially arranged along the transmission direction of the light path; the first preamplifier is used for amplifying the initial laser beam, the electro-optical modulator is used for modulating the amplified initial laser beam to form a pulse laser beam, and the second preamplifier is used for amplifying the pulse laser beam; the second-stage amplifier comprises a first beam combiner, a first gain fiber and a first pumping source, and the third-stage amplifier comprises a second beam combiner, a second gain fiber and a second pumping source; further comprising: isolator, mode field adapter and collimator. So as to realize the laser beam with the output peak power of more than 41KW, the polarization extinction ratio of more than 18dB, the beam quality of less than 1.3, the output line width of less than or equal to 1MHz and the pulse width of 0.5ns to 10 ns.

Description

Laser device

Technical Field

The embodiment of the utility model relates to the technical field of lasers, in particular to a laser.

Background

In some fields requiring narrow spectral width and high beam quality, such as gravitational wave detection, coherent communication, laser radar, laser frequency doubling, optical parametric oscillation, and coherent beam combining, too wide a linewidth cannot meet the requirement, and therefore, the problem of narrow linewidth (<100MHz) lasers must be considered. The nanosecond linear polarization pulse fiber laser with high peak power of 1um has the advantages of good beam quality, controllable pulse waveform, small volume and the like, and is further widely applied.

However, in the amplification process of the narrow linewidth seed signal, whether a high-power continuous laser or a high-peak power pulse laser is limited by the Stimulated Brillouin Scattering (SBS) effect. At present, the SBS sound wave field can not be established mainly by means of ultrashort high doping and shortening pulse width, and the generation of SBS effect is inhibited. However, the final peak power of the laser cannot meet the larger requirement, and the pulse width cannot be tuned.

SUMMERY OF THE UTILITY MODEL

The utility model provides a laser, which is used for improving the stimulated Brillouin scattering effect, wherein the output peak power is more than 41KW, the polarization extinction ratio is more than 18dB, the beam quality is less than 1.3, the output line width is less than or equal to 1MHz, and the pulse width is between 0.5ns and 10 ns.

To achieve the above object, the present invention provides a laser, including: a seed source for outputting initial laser, a first-stage amplifier for preventing amplification, a second-stage amplifier for second amplification and a third-stage amplifier for third amplification, which are sequentially arranged along the transmission direction of the light path;

the first-stage amplifier comprises a first preamplifier, an electro-optic modulator and a second preamplifier, the first preamplifier is used for amplifying the initial laser beam, the electro-optic modulator is used for modulating the amplified initial laser beam to form a pulse laser beam, and the second preamplifier is used for amplifying the pulse laser beam;

the second-stage amplifier comprises a first beam combiner, a first gain fiber and a first pump source, and the third-stage amplifier comprises a second beam combiner, a second gain fiber and a second pump source; the fiber core of the first gain fiber is smaller than that of the second gain fiber;

further comprising: the isolator and the mode field adapter are sequentially arranged between the second-stage amplifier and the third-stage amplifier along the optical path transmission direction;

the laser device also comprises a collimator connected with the third-stage amplifier and used for collimating the laser beam amplified by the third-stage amplifier.

Specifically, the laser further includes: a first cladding optical stripper located between the third stage amplifier and the mode field adapter and a second cladding optical stripper located between the third stage amplifier and the collimator.

Specifically, the laser further includes: a first circulator and a second circulator, the first circulator being located between the first stage amplifier and the second stage amplifier, the second circulator being located between the second stage amplifier and the third stage amplifier.

Specifically, the seed source light source is a 1064nm DFB semiconductor laser.

Specifically, the first pump source is a forward pump source.

Specifically, the first pump source is a semiconductor laser with the maximum output power of 20W and the center wavelength of 976 nm.

Specifically, the second pump source is multiple and is a reverse pump source.

Specifically, the single second pump source is a semiconductor laser with the maximum output power of 70W and the center wavelength of 976 nm.

Specifically, the first gain fiber is a 4m double-clad polarization-maintaining ytterbium-doped fiber of 10/125 um.

Specifically, the second gain fiber is a 4m double-clad polarization-maintaining ytterbium-doped fiber of 25/250 um.

Specifically, the first preamplifier and the second preamplifier each comprise a single clad amplifier comprising a plurality of third pump sources, a wavelength division multiplexer, and a third gain fiber;

the single third pumping source is a semiconductor laser with the maximum output power of 600mW and the central wavelength of 976nm, the wavelength division multiplexer is an 980/1064nm wavelength division multiplexer, and the third gain optical fiber is a polarization-maintaining ytterbium-doped optical fiber with the length of 5 m.

According to the utility model, a laser is provided, comprising: a seed source for outputting initial laser, a first-stage amplifier for preventing amplification, a second-stage amplifier for second amplification and a third-stage amplifier for third amplification, which are sequentially arranged along the transmission direction of the light path; the first-stage amplifier comprises a first preamplifier, an electro-optical modulator and a second preamplifier, the first preamplifier is used for amplifying the initial laser beam, the electro-optical modulator is used for modulating the amplified initial laser beam to form a pulse laser beam, and the second preamplifier is used for amplifying the pulse laser beam; the second-stage amplifier comprises a first beam combiner, a first gain fiber and a first pumping source, and the third-stage amplifier comprises a second beam combiner, a second gain fiber and a second pumping source; further comprising: the isolator and the mode field adapter are sequentially arranged between the second-stage amplifier and the third-stage amplifier along the light path transmission direction; the laser device also comprises a collimator connected with the third-stage amplifier and used for collimating the laser beam amplified by the third-stage amplifier. So as to realize the laser beam with the output peak power of more than 41KW, the polarization extinction ratio of more than 18dB, the beam quality of less than 1.3, the output line width of less than or equal to 1MHz and the pulse width of 0.5ns to 10 ns.

Drawings

Fig. 1 is a schematic structural diagram of a laser according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a laser according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a laser according to another embodiment of the present invention;

FIG. 4 is a diagram of a laser beam 41kW, 3ns, and 1MHz spectrum output by a collimator of a laser according to an embodiment of the present invention;

FIG. 5 is a graph of the spectrum of a seed source of a laser according to an embodiment of the present invention;

FIG. 6 is a pulse width plot of a laser beam output by a collimator of a laser according to an embodiment of the present invention;

fig. 7 is a graph of the repetition frequency of the laser beam output by the collimator of the laser according to the embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a laser according to an embodiment of the present invention. As shown in fig. 1, the laser 100 includes: a seed source 101 for outputting an initial laser beam, a first-stage amplifier 102 for preventing enlargement, a second-stage amplifier 103 for second amplification, and a third-stage amplifier 104 for third amplification, which are sequentially arranged along the transmission direction of the optical path;

the first stage amplifier 102 comprises a first preamplifier 1021 for amplifying the initial laser beam, an electro-optical modulator 1022 for modulating the amplified initial laser beam to form a pulsed laser beam, and a second preamplifier 1023 for amplifying the pulsed laser beam;

the second-stage amplifier 103 comprises a first combiner 1031, a first gain fiber 1032 and a first pump source 1033, and the third-stage amplifier 104 comprises a second combiner 1041, a second gain fiber 1042 and a second pump source 1043; the core of the first gain fiber 1032 is smaller than the core of the second gain fiber 1042;

further comprising: an isolator 105 and a mode field adapter 106 sequentially arranged between the second-stage amplifier 103 and the third-stage amplifier 104 along the optical path transmission direction;

a collimator 107 connected to the third stage amplifier 104 is further included for collimating the laser beam amplified by the third stage amplifier 104.

It should be noted that the seed source light source 101 is a 1064nm DFB semiconductor laser, and is configured to output a laser beam with a power of 50mW and a line width of 500 kHz; the first preamplifier 1021 in the first-stage amplifier 102 amplifies a laser beam with a power of 50mW and a line width of 500kHz and outputs the laser beam to the electro-optic modulator 1022, the electro-optic modulator 1022 modulates the laser beam amplified by the first preamplifier 1021, outputs a pulse laser beam of 100uW/5ns and 1MHz, and enters the second preamplifier 1023, and the second preamplifier 1023 amplifies the laser beam of 100uW/5ns and 1 MHz. The average power of the laser beam amplified by the second preamplifier 1023 reaches 100 mW.

And then enters a second stage amplifier 103, wherein the first combiner 1031 couples the pump beam of the first pump 1033 and the laser beam amplified by the second pre-amplifier 1023 into the first gain fiber 1032, and the second stage amplifier 103 amplifies the laser beam amplified by the second pre-amplifier 1023.

Then, the laser beam is input to the isolator 105, the isolator 105 isolates the laser beam amplified by the second stage amplifier 103, isolates the pump beam of the first pump source 103 which is not absorbed from stray light in the laser beam, and outputs a laser beam of 10w/5ns and 1 MHz.

Then, the mode field adapter 106 is accessed. Then, the laser beam enters the third-stage amplifier 104, and the second beam combiner 1041 in the third-stage amplifier 104 couples the laser beam and the pump light of the second pump source 1043 into the second gain fiber 1042, so as to amplify the laser beam. Then, the collimator 107 collimates the laser beam amplified by the third stage amplifier 104 to output a 125W/5ns, 1MHz laser beam.

The fiber core of the input end of the mode field adapter 106 is 10/125um, the fiber core of the output end of the mode field adapter 106 is 25/250um, and the front fiber core and the rear fiber core are matched and consistent by using the mode field adapter 106, so that the signal loss of the front laser beam and the rear laser beam is minimum.

The collimator 107 collimates the laser beam to avoid that the return light is too large and damages the third-stage amplifier 104 because the laser beam enters the amplifier for continuous amplification after the end face is reflected by the Fresnel.

In addition, an optical splitter may be connected to the front end of the first-stage amplifier 102, so as to determine whether the pulse seed works normally.

Specifically, as shown in fig. 2, the laser 100 further includes: a first cladding optical stripper 108 and a second cladding optical stripper 109, said first cladding optical stripper 108 being located between said third stage amplifier 104 and said mode field adapter 106, said second cladding optical stripper 109 being located between said third stage amplifier 104 and said collimator 107.

The first cladding light stripper 108 is configured to filter residual pump light that is not absorbed in the first gain fiber 1032 of the third-stage amplifier 104 and stray light of the laser beam passing through the mode field adapter 106, so that the coupled laser beam has a higher purity, and components in the optical path are prevented from being burned by return light. The second cladding optical stripper 109 is configured to filter residual pump light that is not absorbed in the second gain fiber 1042 in the amplified laser beam, so that the signal purity of the finally amplified laser beam is higher, and noise is effectively reduced.

Specifically, as shown in fig. 3, the laser 100 further includes: a first circulator 110 and a second circulator 111, the first circulator 110 being located between the first stage amplifier 102 and the second stage amplifier 103, the second circulator 111 being located between the second stage amplifier 103 and the third stage amplifier 104.

The first circulator 110 and the second circulator 111 are used for monitoring the return light of the laser in real time, and the laser damage caused by the strong return light due to the nonlinear brillouin scattering effect is avoided.

It should be noted that the second circulator 111 may be disposed between the second-stage amplifier 103 and the isolator 105, or between the isolator 105 and the mode field adapter 106, or between the mode field adapter 106 and the first cladding optical stripper 108, or between the first cladding optical stripper 108 and the third-stage amplifier 104.

Specifically, the first pump source 1033 is a forward pump source. That is, the output direction of the pump light of the first pump source 1033 is the same as the laser light emitted from the seed source 101.

Specifically, the first pump source 1033 is a semiconductor laser having a maximum output power of 20W and a center wavelength of 976 nm.

Specifically, there are multiple (4) second pump sources 1043, which are all inverse pump sources. That is, the output direction of the pump light of the second pump source 1043 is opposite to the laser light emitted from the seed source 101. The reverse pump source can amplify the laser beam with less energy.

Specifically, the single second pump source 1043 is a semiconductor laser with a maximum output power of 70W and a center wavelength of 976 nm.

It can be understood that the pump source has a central wavelength of 976nm, which provides high optical-to-optical conversion efficiency, and can use a shorter active fiber to obtain higher output power.

Specifically, the first gain fiber 1032 is a 4m double-clad polarization-maintaining ytterbium-doped fiber of 10/125 um.

Specifically, the second gain fiber 1042 is a 4m double-clad polarization-maintaining ytterbium-doped fiber of 25/250 um.

The double-cladding polarization-maintaining ytterbium-doped fiber is transmitted in a fiber core based on signal light, and pump light is transmitted in an inner cladding, so that a multimode laser diode array can be used as a pump source, the pump light is injected into the inner cladding of the doped fiber in an oblique incidence mode and repeatedly passes through the fiber core in a fold line mode, the pump light is absorbed by rare ytterbium ions in the fiber core, and high-power laser output is achieved. The output spectrum of the 1064nm pulsed laser is shown in FIG. 4. Because the light sources are all made of polarization maintaining fibers, the polarization state of the output 1064nm laser cannot change along with the temperature.

Specifically, the first preamplifier 1021 and the second preamplifier 1023 each comprise a single clad amplifier comprising a plurality of third pump sources, a wavelength division multiplexer, and a third gain fiber;

the single third pumping source is a semiconductor laser with the maximum output power of 600mW and the central wavelength of 976nm, the wavelength division multiplexer is an 980/1064nm wavelength division multiplexer, and the third gain fiber is a single-cladding polarization-maintaining ytterbium-doped fiber with the length of 5 m.

Specifically, the laser 100 further comprises a temperature sensor for monitoring the temperature of the laser 100. And the water cooling system is used for ensuring that the pumping source in the laser 100 can work under a constant temperature of 25 ℃. The water cooling system may be a water cooling system known to those skilled in the art, and the present invention is not limited thereto.

The laser provided by the utility model adopts a stable semiconductor narrow-linewidth laser as a seed source, adopts a 1064nm high-switching-ratio electro-optic modulator to modulate direct current light into pulse light, adopts a multi-stage MOPA structure ytterbium-doped optical fiber amplifier to amplify, has average power up to 125W, peak power up to 41KW (@3ns and 1MHz) (as shown in figure 4), has adjustable pulse width (0.5ns-10ns) and full optical path polarization maintaining, has a polarization extinction ratio up to 13dB, and adopts an inhibition mode means internally, so that the laser can obtain better light beam quality factors (Brillouin scattering in the laser is improved through two-stage different optical fiber cores). Finally, isolation collimation output is adopted, so that the laser cannot be damaged by return light, and the laser can work reliably and safely. And through temperature monitoring, return light monitoring, quick response protection. In addition, the good water cooling system ensures the safety and reliability of the laser.

Fig. 5 is a spectrum diagram of a seed source of a laser according to an embodiment of the present invention. In fig. 5, N has a value of 20. Fig. 6 is a pulse width diagram of a laser beam output by a collimator of a laser according to an embodiment of the present invention. In fig. 6, the laser beam has a pulse width of 1ns, a repetition frequency of 1MHz, and a peak power of 125W. Fig. 7 is a graph of the repetition frequency of the laser beam output by the collimator of the laser according to the embodiment of the present invention. In fig. 7, the repetition frequency is 1 MHz.

In summary, the laser provided by the present invention adopts a MOPA optical path structure in the structure, including: a seed source for outputting initial laser, a first-stage amplifier for preventing amplification, a second-stage amplifier for second amplification and a third-stage amplifier for third amplification, which are sequentially arranged along the transmission direction of the light path; the first-stage amplifier comprises a first preamplifier, an electro-optical modulator and a second preamplifier, the first preamplifier is used for amplifying the initial laser beam, the electro-optical modulator is used for modulating the amplified initial laser beam to form a pulse laser beam, and the second preamplifier is used for amplifying the pulse laser beam; the second-stage amplifier comprises a first beam combiner, a first gain fiber and a first pumping source, and the third-stage amplifier comprises a second beam combiner, a second gain fiber and a second pumping source; further comprising: the isolator and the mode field adapter are sequentially arranged between the second-stage amplifier and the third-stage amplifier along the light path transmission direction; the laser device also comprises a collimator connected with the third-stage amplifier and used for collimating the laser beam amplified by the third-stage amplifier. So as to realize the laser beam with the output peak power of more than 41KW, the polarization extinction ratio of more than 18dB, the beam quality of less than 1.3, the output line width of less than or equal to 1MHz and the pulse width of 0.5ns to 10 ns.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (11)

1. A laser, comprising: a seed source for outputting an initial laser beam, a first-stage amplifier for preventing amplification, a second-stage amplifier for second amplification and a third-stage amplifier for third amplification are sequentially arranged along the transmission direction of the light path;

the first-stage amplifier comprises a first preamplifier, an electro-optic modulator and a second preamplifier, the first preamplifier is used for amplifying the initial laser beam, the electro-optic modulator is used for modulating the amplified initial laser beam to form a pulse laser beam, and the second preamplifier is used for amplifying the pulse laser beam;

the second-stage amplifier comprises a first beam combiner, a first gain fiber and a first pump source, and the third-stage amplifier comprises a second beam combiner, a second gain fiber and a second pump source; the fiber core of the first gain fiber is smaller than that of the second gain fiber;

further comprising: the isolator and the mode field adapter are sequentially arranged between the second-stage amplifier and the third-stage amplifier along the optical path transmission direction;

the laser device also comprises a collimator connected with the third-stage amplifier and used for collimating the laser beam amplified by the third-stage amplifier.

2. The laser of claim 1, further comprising: a first cladding optical stripper located between the third stage amplifier and the mode field adapter and a second cladding optical stripper located between the third stage amplifier and the collimator.

3. The laser of claim 1 or 2, further comprising: a first circulator and a second circulator, the first circulator being located between the first stage amplifier and the second stage amplifier, the second circulator being located between the second stage amplifier and the third stage amplifier.

4. The laser of claim 1, wherein the seed source light source is a 1064nm DFB semiconductor laser.

5. The laser of claim 1, wherein the first pump source is a forward pump source.

6. The laser of claim 5, wherein the first pump source is a semiconductor laser with a maximum output power of 20W and a center wavelength of 976 nm.

7. The laser of claim 1, wherein the second pump source is a plurality of counter-pump sources.

8. The laser of claim 7, wherein a single said second pump source is a semiconductor laser with a maximum output power of 70W and a center wavelength of 976 nm.

9. The laser of claim 1, wherein the first gain fiber is a 4m 10/125um double-clad polarization-maintaining ytterbium-doped fiber.

10. The laser of claim 1, wherein the second gain fiber is a 4m 25/250um double-clad polarization-maintaining ytterbium-doped fiber.

11. The laser of claim 1, wherein the first preamplifier and the second preamplifier each comprise a single clad amplifier comprising a plurality of third pump sources, a wavelength division multiplexer, and a third gain fiber;

the single third pumping source is a semiconductor laser with the maximum output power of 600mW and the central wavelength of 976nm, the wavelength division multiplexer is an 980/1064nm wavelength division multiplexer, and the third gain optical fiber is a polarization-maintaining ytterbium-doped optical fiber with the length of 5 m.

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