CN112152057A - A fast-response fiber laser - Google Patents

Abstract

The invention provides a quick response fiber laser, which belongs to the technical field of lasers and comprises a pumping source and a gain fiber, wherein the pumping source is arranged along the direction of the gain fiber, pumping light output by the pumping source is injected into the gain fiber, and the core cladding ratio of the gain fiber is between 5% and 10%. By adopting the gain optical fiber with high core cladding ratio, the response time of the resonant cavity of the optical fiber laser can be improved, so that the faster laser response speed can be obtained, the response time of the laser can be shortened, and the response time of different power sections can be ensured to be consistent.

Description

A fast-response fiber laser

technical field

The present invention relates to the technical field of lasers, in particular to a fast-response fiber laser.

Background technique

Existing laser design schemes are mainly aimed at conventional application fields, and the overall response time requirement is generally around 50us to 100us. The response time t1 of the driver is 1us~10us, the response time t2 of the pump laser is 0.2us~2us, and the response time t3 of the fiber laser resonator is 2us~90us. The response time varies depending on the output laser power. In some special applications In fields such as ultra-fast laser material processing and advanced manufacturing, laser cutting, welding, 3D printing and other fields, the laser response time is generally required to be within 10us, and the response time of different power segments should be as consistent as possible. The current laser design schemes are often difficult to achieve fast laser response in the full power range.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a fast-response fiber laser, which can obtain a faster laser response speed and has the same response time in different power segments.

Embodiments of the present invention are implemented as follows:

An embodiment of the present invention provides a fast-response fiber laser, which includes a pump source and a gain fiber, the pump source is arranged along the direction of the gain fiber, and the pump light output by the pump source is injected into the gain fiber , the core-to-pack ratio of the gain fiber is between 5% and 10%.

Optionally, the core diameter of the gain fiber is between 4um and 20um, and the cladding diameter of the gain fiber is between 120um and 400um.

Optionally, the core material of the gain fiber is doped with ytterbium element, and the doping concentration of the ytterbium element is 4×10 ²⁵ /m ³ to 30×10 ²⁵ /m ³ .

Optionally, the pump source is a semiconductor laser, the center wavelength of the semiconductor laser is between 974.5 nm and 977.5 nm, and the bandwidth of the semiconductor laser is between 1 nm and 3 nm.

Optionally, the numerical aperture of the gain fiber is between 0.05 and 0.18.

Optionally, it further includes a beam combiner arranged between the pump source and the gain fiber, and the pump light output from the pump source is coupled into the gain fiber through the beam combiner.

Optionally, the pump source is injected into the gain fiber along the transmission direction of the optical signal, a first high-reflection grating is arranged between the beam combiner and the gain fiber, and the gain fiber is far from the pump. One end of the source is provided with a low reflection grating.

Optionally, the pump source is injected into the gain fiber in a direction opposite to the transmission direction of the optical signal, and the end of the gain fiber away from the beam combiner is provided with a second high-reflection grating, and the pump source The end away from the beam combiner is provided with a third high-reflection grating.

Optionally, a mode stripper is provided at one end of the third high-reflection grating away from the pump source.

Optionally, one end of the second high-reflection grating away from the gain fiber is provided with a first pump source and a first beam combiner, and the first beam combiner is close to the second high-reflection grating.

The beneficial effects of the embodiments of the present invention include:

The fast-response fiber laser provided by the embodiment of the present invention includes a pump source and a gain fiber, the pump source is arranged along the direction of the gain fiber, the pump light output by the pump source is injected into the gain fiber, and the core-to-pack ratio of the gain fiber is 5 Between % and 10%, the use of a gain fiber with a high core-to-pack ratio can improve the response time of the fiber laser resonator to obtain a faster laser response speed, shorten the laser response time, and ensure that the response time of different power ranges is consistent.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is one of the schematic structural diagrams of a fast-response fiber laser provided by an embodiment of the present invention;

FIG. 2 is a second schematic structural diagram of a fast-response fiber laser provided by an embodiment of the present invention;

FIG. 3 is a third schematic structural diagram of a fast-response fiber laser provided by an embodiment of the present invention.

Icon: 10-red light source; 11-pump source; 12-beam combiner; 13-first high-reflection grating; 14-gain fiber; 15-low-reflection grating; 16-mode stripper; 17-end cap; 18 - the second high-reflection grating; 19- the third high-reflection grating; 20- the first pump source; 21- the first beam combiner.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Thus, the following detailed description of the embodiments of the invention provided in the accompanying drawings are not intended to limit the scope of the invention as claimed, but are merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in use, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying The device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first", "second", "third", etc. are only used to differentiate the description and should not be construed as indicating or implying relative importance.

Furthermore, terms such as "horizontal", "vertical" etc. do not imply that a component is required to be absolutely horizontal or overhang, but rather may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal than "vertical", it does not mean that the structure must be completely horizontal, but can be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "arranged", "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection, It can also be a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or the internal communication between the two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

This embodiment provides a fast-response fiber laser, which includes a pump source 11 and a gain fiber 14, the pump source 11 is arranged along the direction of the gain fiber 14, and the pump light output by the pump source 11 is injected into the gain fiber 14, and the gain The core-to-package ratio of the optical fiber 14 is between 5% and 10%.

The pump source 11 outputs pump light, and the pump light is injected into the gain fiber 14 . The pump source 11 can be a semiconductor laser with a center wavelength of 974.5nm to 977.5nm and a bandwidth of 1nm to 3nm; when the pump source 11 is a semiconductor laser, the active fiber in the pump fiber is 135/155 (135um diameter). Core, 155um diameter cladding) output fiber, NA (numerical aperture) is 0.05 ~ 0.18.

The core-to-pack ratio of the gain fiber 14 is between 5% and 10%, and the core-to-pack ratio refers to the ratio of the core diameter to the cladding diameter of the gain fiber 14. Using a gain fiber 14 with a high core-to-pack ratio can improve the efficiency of the fiber laser. The corresponding time of the resonant cavity can be obtained to obtain a faster laser response speed and shorten the laser response time. By using the gain fiber 14 with the core-to-pack ratio, the response time of the laser can be shortened to less than 10us. Moreover, the use of the gain fiber 14 with a high core-to-pack ratio can ensure that the response times of different power segments are consistent.

In the fast-response fiber laser provided by the embodiment of the present invention, by setting the core-to-pack ratio of the gain fiber 14 between 5% and 10%, and using the gain fiber 14 with a high core-to-pack ratio, the corresponding time of the resonant cavity of the fiber laser can be improved, so that the Obtain faster laser response speed, shorten laser response time, and ensure consistent response time in different power segments.

Specifically, the core diameter of the gain fiber 14 is between 4um and 20um, and the cladding diameter of the gain fiber 14 is between 120um and 400um.

The core material of the gain fiber 14 is doped with ytterbium element, and the doping concentration of ytterbium element is 4×10 ²⁵ /m ³ to 30×10 ²⁵ /m ³ , which means that the core material of 1 m ³ is doped with 4×10 ²⁵ ~ ³⁰ x 1025 ytterbium particles.

The purpose of doping ytterbium element is to promote the transformation of passive transmission fiber into active fiber with amplification ability.

The following three embodiments are used to illustrate:

Example 1

Referring to FIG. 1 , a beam combiner 12 is further disposed between the pump source 11 and the gain fiber 14 , and the pump light output by the pump source 11 is coupled into the gain fiber 14 through the beam combiner 12 .

The beam combiner 12 is mainly used to combine multiple paths of pump light into a gain fiber for output, and is mainly used to increase the pump power.

This embodiment is forward pumping, that is, the pump light and the optical signal are injected into the gain fiber 14 in the same direction, the red light source 10 emits red light, the red light signal is transmitted to the right, and the pump light output by the pump source 11 is along the optical signal. In the transmission direction, it is injected into the gain fiber 14 through the beam combiner 12 and injected into the gain fiber 14, and the pump light is also transmitted to the right.

A first high-inversion grating 13 is provided between the beam combiner 12 and the gain fiber 14 , and a low-inversion grating 15 is provided at the end of the gain fiber 14 away from the pump source 11 . A mode stripper 16 is provided at one end of the low-reflection grating 15 away from the gain fiber 14, and the residual pump light or cladding light is stripped by the mode stripper 16 and then output.

Wherein, in this embodiment, a gain fiber 14 with a core diameter of 14um and a cladding diameter of 250um may be used; or, a gain fiber 14 with a core diameter of 20um and a cladding diameter of 250um may be used.

For the core-to-clad ratio of the gain fiber 14, the larger the core diameter, the larger the absorption cross-section, the stronger the pump light absorption; the smaller the cladding diameter, the larger the pump light power density, and the stronger the pump light absorption; The larger the core-to-package ratio of the fiber, the higher the absorption efficiency and the faster the response speed. For example, the core-pack ratio of 14/250 is about twice the absorption efficiency of the core-pack ratio of 20/400.

Embodiment 2

Please refer to FIG. 2 , this embodiment is reverse pumping, that is, the pump light and the optical signal are injected into the two ends of the gain fiber 14 in different directions, and the pump light output by the pump source is in the opposite direction to the transmission direction of the optical signal. Inject into the gain fiber 14, the red light signal emitted by the red light source 10 is transmitted to the right, the pump light output by the pump source 11 is injected into the gain fiber 14 through the beam combiner 12 in the opposite direction of the transmission direction of the optical signal, and the pump light is directed to the left transmission.

The end of the gain fiber 14 away from the beam combiner 12 is provided with a second high-reflection grating 18 , and the end of the pump source 11 away from the beam combiner 12 is provided with a third high-reflection grating 19 . One end of the third high-reflection grating 19 away from the pump source 11 is provided with a stripper 16 .

The beam combiner 12 is located between the gain fiber 14 and the third high-reflection grating 19. At this time, the beam combiner 12 is a reverse beam combiner. The red light signal emitted by the red light source 10 is injected into the gain fiber 14 from the left end, and the pump source 11 The output pump light is injected into the gain fiber 14 from the right end of the gain fiber 14 through the beam combiner 12. Since the laser is mainly generated in the rear section (right end) of the gain fiber 14, the reverse pumping can fully pump the laser power and improve the light conversion efficiency, reducing nonlinear effects. Other parameters are the same as for forward pump.

Embodiment 3

Referring to FIG. 3 , on the basis of Embodiment 2, this embodiment adopts bidirectional pumping.

One end of the second high-reflection grating 18 away from the gain fiber 14 is provided with a first pump source 20 and a first beam combiner 21 , and the first beam combiner 21 is close to the second high-reflection grating 18 .

This embodiment has two pump sources and two beam combiners, which are respectively the pump source 11 and the first pump source 20 , and the beam combiner 12 and the first beam combiner 21 . The pump source 11 and the beam combiner 12 are located at the same end of the gain fiber 14 , and the first pump source 20 and the first beam combiner 21 are located at the other end of the gain fiber 14 .

The pump light output by the first pump source 20 is injected into one end of the gain fiber 14 in the same direction as the optical signal through the first beam combiner 21 and the second high-reflection grating 18, and the pump light output by the pump source 11 is passed through the beam combiner. 12 is injected into the other end of the gain fiber 14 in the opposite direction to the optical signal. The pump light of the first pump source 20 and the optical signal are injected into the gain fiber 14 in the same direction, and the pump light of the pump source 11 is injected into the gain fiber 14 from the opposite direction. This bidirectional pumping combines the advantages of forward pumping and reverse pumping, so that the pump light is evenly distributed in the gain fiber, so that the pump power at both ends of the gain fiber 14 can be equalized, and the distribution of the reverse particle number is more uniform. At the same time, the heat dissipation pressure is smaller. Other parameters are the same as for forward pump.

In addition, in the above three embodiments, the output end of the stripper 16 is also provided with an end cap 17 or a fiber laser cable (QBH), which is used as an optical output interface for high-power fiber laser transmission.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a fast-response fiber laser, characterized in that, comprising a pump source and a gain fiber, the pump source is arranged along the direction of the gain fiber, and the pump light output by the pump source is injected into the gain fiber , the core-to-pack ratio of the gain fiber is between 5% and 10%. 2 . The fast-response fiber laser according to claim 1 , wherein the core diameter of the gain fiber is between 4um and 20um, and the cladding diameter of the gain fiber is between 120um and 400um. 3 . 3 . The fast-response fiber laser according to claim 1 , wherein the core material of the gain fiber is doped with ytterbium element, and the doping concentration of the ytterbium element is 4×10 ²⁵ /m ³ -30 . ×10 ²⁵ /m ³ . 4 . The fast-response fiber laser according to claim 1 , wherein the pump source is a semiconductor laser, the center wavelength of the semiconductor laser is between 974.5 nm and 977.5 nm, and the bandwidth of the semiconductor laser is between 974.5 nm and 977.5 nm. 5 . Between 1nm and 3nm. 5 . The fast-response fiber laser according to claim 1 , wherein the numerical aperture of the gain fiber is between 0.05 and 0.18. 6 . 6. The fast-response fiber laser according to any one of claims 1 to 5, further comprising a beam combiner arranged between the pump source and the gain fiber, and the pump source outputs The pump light is coupled into the gain fiber through the beam combiner. 7 . The fast-response fiber laser according to claim 6 , wherein the pump light output by the pump source is injected into the gain fiber along the transmission direction of the optical signal, and the beam combiner and the gain fiber are 7 . A first high-inversion grating is arranged therebetween, and a low-inversion grating is arranged at the end of the gain fiber away from the pump source. 8 . The fast-response fiber laser according to claim 6 , wherein the pump light output by the pump source is injected into the gain fiber in a direction opposite to the transmission direction of the optical signal, and the gain fiber is far away from the optical signal. 9 . One end of the beam combiner is provided with a second high-reflection grating, and one end of the pump source away from the beam combiner is provided with a third high-reflection grating. 9 . The fast-response fiber laser according to claim 8 , wherein a mode stripper is provided at one end of the third high-reflection grating away from the pump source. 10 . 10. The fast-response fiber laser according to claim 9, wherein a first pump source and a first beam combiner are provided at one end of the second high-reflection grating away from the gain fiber, and the first A beam combiner is close to the second high-reflection grating.

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