Laser amplifier

Abstract

The utility model discloses a laser amplifier, and relates to the technical field of laser amplification. The signal input end of the forward pump is used for being connected with a laser signal source; the input end of the cladding optical gain optical fiber is communicated with the signal output end of the forward pump, and the cladding optical gain optical fiber comprises a plurality of laser amplification sections; a first inclined grating; and, a backward pump. According to the technical scheme of the utility model, when the spontaneous radiation light generated by the pump light passes through the inclined grating, the inclined grating can filter the spontaneous radiation light, so that the spontaneous radiation light generated in one laser amplification section is prevented from entering the next laser amplification section; therefore, amplification of spontaneous radiation light in the laser amplification section is reduced, and the problem that the gain extraction rate of a laser signal is reduced is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to laser amplification technical field, especially a kind of laser amplifier. BACKGROUND

[0002] In laser amplifier, according to the different pumping intensity, gain medium can be in weak excitation state, inversion excitation state and super-threshold excitation state, which correspondingly produce fluorescence, amplified spontaneous emission and laser in amplifier.

[0003] In the case of high-power pumping, the gain of amplifier will rapidly increase, the particles in upper energy level will spontaneously jump to lower energy level before signal light reaches, spontaneous emission is generated in this process, and the energy stored in gain fiber will be extracted, a large number of upper energy level inversion particles are consumed, resulting in the decrease of laser signal extraction rate of gain. UTILITY MODEL CONTENT

[0004] The main purpose of the utility model is to provide a kind of laser amplifier, to improve the problem of the decrease of laser signal extraction rate of gain.

[0005] To achieve the above-mentioned purpose, the laser amplifier provided by the utility model comprises:

[0006] Forward pumping, the signal input end of the forward pumping is used to connect laser signal source;

[0007] Cladding light gain fiber, the input end of the cladding light gain fiber is communicated with the signal output end of the forward pumping, and the cladding light gain fiber comprises a plurality of laser amplification segments sequentially connected end to end;

[0008] At least one first inclined grating, the first inclined grating is communicated with two adjacent laser amplification segments;And,

[0009] Backward pumping, the signal input end of the backward pumping is communicated with the output end of the cladding light gain fiber, and the signal output end of the backward pumping is used to output amplified laser.

[0010] In an embodiment, the laser amplifier further comprises a first isolator, the input end of the first isolator is connected with the output end of the laser signal source, the output end of the first isolator is connected with the signal input end of the forward pumping, and the first isolator is used to isolate the return light towards the laser signal source.

[0011] In an embodiment, the isolator comprises a three-port isolator, and the three-port isolator has a return light output end, and the return light output end is used to connect a return light detection component.

[0012] In an embodiment, the laser amplifier further comprises a first cladding light filter, an input end of the first cladding light filter being connected to an output end of the laser signal source, and an output end of the first cladding light filter being connected to an input end of the forward-pumped signal.

[0013] In an embodiment, the laser amplifier further comprises a first isolator, the first isolator connecting the laser signal source and the first cladding light filter.

[0014] In an embodiment, the laser amplifier further comprises a second tilted grating, an input end of the second tilted grating being connected to an output end of the laser signal source, and an output end of the second tilted grating being connected to an input end of the forward-pumped signal.

[0015] In an embodiment, the laser amplifier further comprises a second cladding light filter, an input end of the second cladding light filter being connected to an output end of the backward-pumped signal, and an output end of the second cladding light filter being connected to an input end of the output head.

[0016] In an embodiment, the laser amplifier further comprises a first pump laser module, a pigtail of the first pump laser module being connected to a pump end of the forward-pumped signal.

[0017] In an embodiment, the laser amplifier further comprises a second pump laser module, a pigtail of the second pump laser module being connected to a pump end of the backward-pumped signal.

[0018] In an embodiment, the laser amplifier further comprises a laser signal source, an output end of the laser signal source being connected to an input end of the forward-pumped signal; and / or,

[0019] The laser amplifier further comprises an output head, an input end of the output head being connected to an output end of the backward-pumped signal.

[0020] The technical scheme of the utility model discloses a structure that signal light is input to forward pumping, and the laser signal output by the laser signal source can enter each laser amplification section through the forward pumping, and the pump light output by the forward pumping and the backward pumping can enter each laser amplification section, the laser signal can be amplified in the laser amplification section during the movement of the laser signal, and the amplified laser signal is output from the output end of the backward pumping, the spontaneous emission light generated by the pump light can be filtered by the inclined grating when passing through the inclined grating, the spontaneous emission light generated in one laser amplification section is reduced from entering the next laser amplification section, the consumption of the pump light by the spontaneous emission light is reduced, the amplification of the spontaneous emission light in the laser amplification section is reduced, the amplified spontaneous emission light is reduced, the consumption of the pump light by the laser signal is improved, the output of the laser signal is improved, and the problem of the extraction rate reduction of the gain by the laser signal is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to the structures shown in these drawings without creative labor for those skilled in the art.

[0022] Figure 1 The structure schematic diagram of the first embodiment of the laser amplifier provided by the utility model is shown in the figure.

[0023] Figure 2 The structure schematic diagram of the second embodiment of the laser amplifier provided by the utility model is shown in the figure.

[0024] Figure 3 The structure schematic diagram of the third embodiment of the laser amplifier provided by the utility model is shown in the figure.

[0025] EXPLANATION OF DRAWINGS:

[0026] 1, forward pumping, 11, first pump laser module, 2, cladding light gain optical fiber, 21, first laser amplification section, 22, second laser amplification section, 23, third laser amplification section, 3, first inclined grating, 4, backward pumping, 41, second pump laser module, 5, first isolator, 6, first cladding light filter, 7, second inclined grating, 8, second cladding light filter, 9, laser signal source, 10, output head.

[0027] The implementation, functional characteristics and advantages of the utility model will be further explained by combining with the embodiments and referring to the drawings. DETAILED DESCRIPTION

[0028] Clearly and completely describe the technical solutions in the embodiments of the utility model with reference to the drawings in the embodiments of the utility model, obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skilled in the art without making creative efforts belong to the scope of protection of the utility model.

[0029] It should be noted that if the embodiments of the utility model involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture, and if the certain posture changes, the directional indications will also change accordingly.

[0030] In addition, if the embodiments of the utility model involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel solutions are included, for example, "A and / or B" includes A solution, or B solution, or A and B solutions. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that the ordinary skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0031] In the laser amplifier, according to the different pumping strength, the gain medium can be in weak excitation state, inversion excitation state and super threshold excitation state, and the corresponding fluorescence, amplified spontaneous emission (ASE) and laser are generated in the amplifier.

[0032] In the case of high-power pumping, the gain of the amplifier will increase rapidly, and the particles in the upper energy level will spontaneously jump to the lower energy level before the signal light reaches, in this process, spontaneous emission is generated, and the energy stored in the gain fiber is extracted, a large number of upper energy level inversion particle numbers are consumed, resulting in a decrease in the extraction rate of the laser signal to the gain, in addition, due to the fact that ASE can be transmitted in the opposite direction in the fiber laser amplifier, not only will it cause the signal laser power to decrease, but also will cause serious interference and damage to the front-end device and the system, and will affect the stability of the entire laser.

[0033] The utility model provides a kind of laser amplifier.

[0034] Please refer to Figure 1、 Figure 2 and Figure 3 In an embodiment of the utility model, the laser amplifier comprises;

[0035] The forward pump 1 is used for connecting the laser signal source 9 at the signal input end;

[0036] The cladding light gain optical fiber 2 is connected with the signal output end of the forward pump 1 at the input end, and the cladding light gain optical fiber 2 comprises a plurality of laser amplification sections sequentially communicated in head-tail mode;

[0037] At least one first inclined grating 3 is communicated with two adjacent laser amplification sections; and,

[0038] The backward pump 4 is communicated with the output end of the cladding light gain optical fiber 2 at the signal input end, and the signal output end of the backward pump 4 is used for outputting the amplified laser.

[0039] The technical scheme of the utility model is that after the signal light is input into the forward pump 1, the laser signal output by the laser signal source 9 can enter each laser amplification section through the forward pump 1, and the pump light output by the forward pump 1 and the backward pump 4 can enter each laser amplification section, the laser signal can be amplified in the laser amplification section during the movement of the laser signal, and the amplified laser signal is output from the output end of the backward pump 4; when the spontaneous emission light generated by the pump light passes through the inclined grating, the inclined grating can filter the spontaneous emission light, reduce the spontaneous emission light generated in one laser amplification section from entering the next laser amplification section, reduce the consumption of the pump light by the spontaneous emission light, thereby reducing the amplification of the spontaneous emission light in the laser amplification section, reducing the amplified spontaneous emission light, improving the consumption of the pump light by the laser signal, improving the output of the laser signal, and improving the problem of the reduction of the extraction rate of the gain by the laser signal.

[0040] Please refer to Figure 1 In the first embodiment, the laser amplifier further comprises a first isolator 5, the input end of the first isolator 5 is connected with the output end of the laser signal source 9, the output end of the first isolator 5 is connected with the signal input end of the forward pump 1, and the first isolator 5 is used for isolating the return light to the laser signal source 9. By arranging the first isolator 5, the laser emitted by the laser signal source 9 can be unidirectionally emitted to the first isolator 5, when the spontaneous emission light in the cladding light gain optical fiber 2 passes through the forward pump 1 and moves to the laser signal source 9, the first isolator 5 can isolate the spontaneous emission light, reduce the spontaneous emission light entering the laser signal source 9, and protect the laser signal source 9.

[0041] The isolator comprises a three-port isolator having a return light output end for connecting a return light detection assembly. Through the return light detection assembly, the return light directed to the laser signal source 9 can be detected to prevent the isolator and the laser signal source 9 from being damaged due to excessive reverse light power. The proportion and wavelength range of ASE in the reverse light can also be determined by analyzing the spectrum, which can be used as data for optimizing the first slanted grating 3.

[0042] The laser amplifier further comprises a first cladding light filter 6, an input end of which is connected to an output end of the laser signal source 9, and an output end of which is connected to a signal input end of the forward pump 1. The first cladding light filter 6 can remove noise and clutter in the signal laser emitted by the laser signal source 9, thereby improving the purity of the laser signal.

[0043] The first isolator 5 is connected between the laser signal source 9 and the first cladding light filter 6, and can protect the laser signal source 9.

[0044] Referring to Figure 2 and Figure 3 , in the second embodiment, the laser amplifier further comprises a second slanted grating 7, an input end of which is connected to an output end of the laser signal source 9, and an output end of which is connected to a signal input end of the forward pump 1.

[0045] With the second slanted grating 7, the spontaneous emission emitted by the laser signal source 9 can be filtered out, thereby reducing the spontaneous emission entering the forward pump 1 and reducing the amplified spontaneous emission.

[0046] Specifically, the second slanted grating 7 is arranged between the first isolator 5 and the cladding light filter, and through the second slanted grating 7, the spontaneous emission emitted by the first isolator 5 and directed to the cladding light filter can be filtered out.

[0047] Referring to Figure 2 and Figure 3 , the laser amplifier further comprises a second cladding light filter 8, an input end of which is connected to a signal output end of the backward pump 4, and an output end of which is connected to an input end of the output head 10. Through the second cladding light filter 8, noise and clutter in the amplified laser output by the backward pump 4 can be filtered out.

[0048] The laser amplifier further comprises a first pump laser module 11, a tail fiber of the first pump laser module 11 is connected with a pump end of the forward pump 1. Through the first pump laser module 11, the forward pump 1 can be provided with pump energy.

[0049] The laser amplifier further comprises a second pump laser module 41, a tail fiber of the second pump laser module 41 is connected with a pump end of the backward pump 4. Through the second pump laser module 41, the backward pump 4 can be provided with pump energy.

[0050] The laser amplifier further comprises a laser signal source 9, an output end of the laser signal source 9 is connected with a signal input end of the forward pump 1; the laser signal source 9 can stably provide a laser signal.

[0051] The laser amplifier further comprises an output head 10, an input end of the output head 10 is connected with a signal output end of the backward pump 4, the output head 10 can be used for adjusting an angle and heat dissipation of the amplified laser, and the output head 10 belongs to a conventional design in the art.

[0052] The laser amplifier further comprises a laser signal source 9, an output end of the laser signal source 9 is connected with a signal input end of the forward pump 1; the laser amplifier further comprises an output head 10, an input end of the output head 10 is connected with a signal output end of the backward pump 4. Specifically, the laser signal source 9 is a narrow linewidth fiber laser seed source based on phase modulation, the working wavelength of the laser signal source 9 is 1030 nm, and the linewidth is 0.2 nm.

[0053] Please refer to Figure 1, the cladding light gain fiber 2 includes the first laser amplification section 21 and the second laser amplification section 22 communicated in sequence, the length of the first laser amplification section 21 is 5m, the core numerical aperture is 0.065, the core diameter is 20um, the cladding diameter is 400um, and the absorption is 0.43dB / m@915nm; the length of the second laser amplification section 22 is 5m, the core numerical aperture is 0.065, the core diameter is 20um, the cladding diameter is 400um, and the absorption is 0.5dB / m@915nm. The first laser pumping module is pumped with light with a wavelength of 976nm to provide pumping energy for the double-cladding gain fiber, and the pumping power is 1500W; when the first tilted grating 3 is not added in the laser amplifier, the laser output power is about 3000W, the second pumping laser module 41 is pumped with light with a wavelength of 976nm, and the pumping power is about 3500W. The output head 10 outputs signal light with a signal-to-noise ratio of 25dB, and the return light output end of the three-port isolator detects the reverse signal light power of about 6W; when the first tilted grating 3 is added in the laser amplifier, the laser output power is about 3000W, the laser output signal light signal-to-noise ratio is about 30dB, and the return light output end of the three-port isolator detects the reverse signal light power of about 4W. From the experimental results, the addition of the first tilted grating 3 realizes the suppression of amplified spontaneous emission and improves the stability of the laser amplifier.

[0054] Please refer to Figure 1 and Figure 2 When the second tilted grating 7 and the first tilted grating 3 are added in the laser amplifier, the laser output power is about 3000W, the laser output signal light signal-to-noise ratio is about 35dB, and the MMF end of the three-port isolator detects the reverse signal light power of about 2W. From the experimental results, the effect of suppressing amplified spontaneous emission and improving the stability of the laser amplifier is improved.

[0055] Please refer to Figure 1 , Figure 2 and Figure 3 In the third embodiment, the cladding light gain fiber 2 includes the first laser amplification section 21, the second laser amplification section 22 and the third laser amplification section 23 communicated in sequence, and the first tilted grating 3 is provided with two, which further improves the effect of suppressing amplified spontaneous emission and improving the stability of the laser amplifier.

[0056] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A laser amplifier, characterized by, comprising; a forward pump, a signal input end of the forward pump being connected to a laser signal source; a cladding light gain fiber, an input end of the cladding light gain fiber being connected to a signal output end of the forward pump, the cladding light gain fiber comprising a plurality of laser amplification sections connected in sequence; at least one first slanted grating, the first slanted grating being connected to two adjacent laser amplification sections; and a backward pump, a signal input end of the backward pump being connected to an output end of the cladding light gain fiber, a signal output end of the backward pump being used for outputting amplified laser.

2. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a first isolator, an input end of the first isolator being connected to an output end of the laser signal source, an output end of the first isolator being connected to the signal input end of the forward pump, the first isolator being used for isolating return light directed to the laser signal source.

3. The laser amplifier of claim 2, wherein, The isolator comprises a three-port isolator, the three-port isolator having a return light output end, the return light output end being used for connecting a return light detection component.

4. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a first cladding light filter, an input end of the first cladding light filter being connected to the output end of the laser signal source, an output end of the first cladding light filter being connected to the signal input end of the forward pump.

5. The laser amplifier of claim 4, wherein, The laser amplifier further comprises a first isolator, the first isolator being connected to the laser signal source and the first cladding light filter.

6. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a second slanted grating, an input end of the second slanted grating being connected to the output end of the laser signal source, an output end of the second slanted grating being connected to the signal input end of the forward pump.

7. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a second cladding light filter, an input end of the second cladding light filter being connected to the signal output end of the backward pump, the laser amplifier further comprising an output head, an output end of the second cladding light filter being connected to an input end of the output head.

8. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a first pump laser module, a pigtail of the first pump laser module being connected to a pump end of the forward pump.

9. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a second pump laser module, a pigtail of the second pump laser module being connected to a pump end of the backward pump.

10. The laser amplifier of claim 1, wherein, The laser amplifier further comprises a laser signal source, an output end of the laser signal source being connected to the signal input end of the forward pump; and / or, The laser amplifier further comprises an output head, an input end of the output head being connected to the signal output end of the backward pump.

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