CN212571680U

CN212571680U - Femtosecond fiber laser

Info

Publication number: CN212571680U
Application number: CN202021066125.1U
Authority: CN
Inventors: 周辉
Original assignee: Ji Hua Laboratory
Current assignee: Ji Hua Laboratory
Priority date: 2020-06-10
Filing date: 2020-06-10
Publication date: 2021-02-19
Anticipated expiration: 2030-06-10

Abstract

The utility model provides a femto second fiber laser, include: the utility model provides a femto second fiber laser has special cavity structure, need not optical path mechanical adjustment, can realize the femto second fiber laser output of high average power stable output, has also guaranteed the simple structure nature and the circuit security of device simultaneously; the number of optical components can be reduced, the use of passive optical fibers is reduced, the nonlinear effect is inhibited, and the cost is reduced.

Description

Femtosecond fiber laser

Technical Field

The utility model relates to the technical field of medical equipment, in particular to femto second fiber laser.

Background

In recent years, with the progress of fiber laser technology, a system constructed based on an ultrashort pulse fiber laser has characteristics of compact structure, high conversion efficiency, long-term stable operation and the like, and is widely applied to a plurality of application research fields, wherein the application research of the fiber femtosecond laser is the most typical. Fiber lasers rapidly rise in the development of laser technology due to the characteristics of high efficiency, easy integration, excellent beam quality and the like, and become a hot research topic in academia and industry. The femtosecond fiber laser technology has multiple fields of application and potential development, and also puts higher requirements on the output performance of a laser, and needs to have the characteristics of high laser power, high reliability and the like.

In order to realize high-power laser output in a single optical fiber in the current optical fiber industrial market, an optical fiber laser with a main oscillation power amplification structure is mostly adopted, and the optical fiber laser comprises the following components: a seed laser emitting portion and a power amplifying portion, but have a number of disadvantages. Firstly, a complex control system is needed, for example, when the laser is started, the seed laser must be started first, and when the seed laser is stable, the power amplification stage can be started; when the laser is turned off, the power amplification stage must be turned off first, and the seed laser can be turned off after the determination is completed. If the operation is wrong, the control system is wrong or the temperature is too high, stronger laser self-generated oscillation is generated in the power amplification stage, the gain optical fiber is burnt out, and even all optical path devices are burnt out. Secondly, the use of pumped semiconductor lasers in the seed laser light source and the power amplification stage, respectively, and the use of different driving circuits and complex control circuits, leads to increased costs. And thirdly, because a pumping/signal optical fiber beam combiner is used between the seed light source and the power amplification stage, the matching of the fiber core mode fields of the injected signal optical fiber and the output optical fiber is not easy to realize, and the output power of the optical fiber is limited. Therefore, the emergence of a femtosecond fiber laser solving the above-mentioned problems is urgently needed.

SUMMERY OF THE UTILITY MODEL

Therefore, there is a need to provide a femtosecond laser capable of realizing a stable output with high average power while ensuring the structural simplicity and circuit safety of the device.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a femtosecond fiber laser comprising: the self-mode-locking optical fiber oscillator comprises a self-mode-locking optical fiber oscillator, a pumping module, a first active optical fiber, a first Bragg grating, a second active optical fiber, a polarization-maintaining optical fiber and an amplifier, wherein the second Bragg grating is engraved on the cladding of the second active optical fiber; wherein:

the self-mode-locking optical fiber oscillator generates and outputs a first femtosecond pulse laser beam, the first femtosecond pulse laser beam enters the pumping module through a polarization-maintaining optical fiber to form pumping light, the pumping light enters the first active optical fiber and oscillates in a resonator formed by the first Bragg grating and the second Bragg grating to form a second femtosecond pulse laser beam, the second femtosecond pulse laser beam is transmitted to the amplifier through the second Bragg grating to form a third femtosecond pulse laser beam after power amplification, the third femtosecond pulse laser beam is output to the self-mode-locking optical fiber oscillator, and the self-mode-locking optical fiber oscillator receives and outputs the femtosecond laser beam with preset energy.

In some of these embodiments, the self-mode-locked fiber oscillator is an all-fiber oscillator.

In some of these embodiments, the pumping module is diode pumped.

In some of these embodiments, the polarization maintaining fiber is a single mode field photonic crystal fiber with a mode field diameter of 9.2 ± 0.5 μm.

In some of these embodiments, the active fibers are doped with gain ions.

In some of these embodiments, the gain ion is one or more of neodymium, ytterbium, erbium, thulium, holmium, dysprosium, or praseodymium.

In some of these embodiments, the active fiber core diameter is 6.2 + -0.5 μm and the mode field diameter is 9.2 + -0.5 μm.

In some of these embodiments, the first bragg grating has a reflectivity equal to or higher than the second bragg grating, which is a regenerative chirped volume bragg grating.

In some of these embodiments, the first active optical fiber core diameter is smaller than the second active optical fiber core diameter, and the first active optical fiber cladding diameter is larger than the second active optical fiber cladding diameter.

In some embodiments, the first femtosecond pulsed laser beam has a wavelength of 1030nm + -5 nm, a pulse width of less than 500fs, a pulse frequency of 100-.

Furthermore, the utility model also provides a working method of femto second fiber laser, including following step:

the self-mode-locked fiber oscillator generates and outputs a first femtosecond pulse laser beam;

the first femtosecond pulse laser beam enters the pumping module through a polarization maintaining fiber to form pumping light;

the pump light enters the first active optical fiber and oscillates in a resonator formed by the first Bragg grating and the second Bragg grating to form a second femtosecond pulse laser beam;

the second femtosecond pulse laser beam is transmitted to the amplifier through the second Bragg grating to be subjected to power amplification to form a third femtosecond pulse laser beam;

and the third femtosecond pulse laser beam is output to the self-mode-locked fiber oscillator, and the self-mode-locked fiber oscillator receives and outputs the femtosecond laser beam with preset energy.

The utility model adopts the above technical scheme's advantage is:

the utility model provides a femtosecond fiber laser, self-mode-locked fiber oscillator produces and exports first femtosecond pulse laser beam, first femtosecond pulse laser beam gets into through polarization maintaining fiber the pumping module forms the pumping light, the pumping light gets into first active fiber and forms second femtosecond pulse laser beam in the oscillation forms in the syntonizer that first Bragg grating and second Bragg grating formed, second femtosecond pulse laser beam passes through second Bragg grating transmit to form third femtosecond pulse laser beam after the power amplification is carried out to the amplifier, third femtosecond pulse laser beam and export to self-mode-locked fiber oscillator, self-mode-locked fiber oscillator receives and exports the femtosecond laser beam of predetermined energy, the femtosecond fiber laser that the utility model provides has special cavity structure, need not optical path mechanical adjustment, the femtosecond fiber laser output with high average power and stable output can be realized, and the structural simplicity and the circuit safety of the device are ensured; the number of optical components can be reduced, the use of passive optical fibers is reduced, the nonlinear effect is inhibited, and the cost is reduced.

Drawings

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 description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a femtosecond fiber laser provided by the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Example 1

Please refer to fig. 1, which is a schematic structural diagram of a femtosecond fiber laser provided by the present invention, including: the self-mode-locked fiber oscillator comprises a self-mode-locked fiber oscillator 110, a pumping module 120, a first active fiber 130, a first Bragg grating 140, a second active fiber 150, a polarization maintaining fiber 160 and an amplifier 170, wherein the cladding of the second active fiber 150 is engraved with the second Bragg grating.

Specifically, the polarization maintaining fiber 160 is disposed between the self-mode-locked fiber oscillator 110 and the pumping module 120, the first active fiber 130 is disposed between the first bragg grating 140 and the second active fiber 150, and the self-mode-locked fiber oscillator 110, the polarization maintaining fiber 160, the pumping module 120, the first active fiber 130, the first bragg grating 150, the second active fiber 160, and the amplifier 170 are sequentially and seamlessly fused to form an all-fiber ring cavity.

It can be understood that the full optical fiber ring cavity with the single-mode structure also plays a role of a laser sensor, and the precision and the stability of the femtosecond optical fiber laser can be improved.

The working principle of the femtosecond fiber laser is as follows:

the self-mode-locked fiber oscillator 110 generates and outputs a first femtosecond pulse laser beam, the first femtosecond pulse laser beam enters the pumping module through a polarization-maintaining fiber to form pumping light, the pumping light enters the first active fiber and oscillates in a resonator formed by the first bragg grating and the second bragg grating to form a second femtosecond pulse laser beam, the second femtosecond pulse laser beam is transmitted to the amplifier through the second bragg grating to form a third femtosecond pulse laser beam after power amplification, the third femtosecond pulse laser beam is output to the self-mode-locked fiber oscillator, and the self-mode-locked fiber oscillator receives and outputs the femtosecond laser beam with preset energy.

It can be understood that the utility model provides an all-fiber ring chamber replaces the chamber mirror in the traditional laser instrument, constitutes the resonant cavity, need not later stage adjustment and maintains the light path, has very strong interference killing feature to environmental change, has improved the stability of system.

Further, the self-mode-locked fiber oscillator 110 is an all-fiber oscillator. It can be understood that the utility model discloses a full fiber oscillator realizes high average power and high peak power femto second output, is showing promotion mode locking laser output average power and peak power, effectively reduces the mode locking threshold value, guarantees to acquire the femto second pulse of high beam quality.

In some embodiments, the pumping module 120 is diode pumped and serves as a pump for subsequent optics.

Specifically, the polarization maintaining fiber 160 receives the femtosecond seed pulse laser beam output from the self-mode-locked fiber oscillator 110, and the pumping module 120 regeneratively amplifies the femtosecond seed pulse laser beam and outputs the amplified femtosecond seed pulse laser beam to the first active fiber 130 for gain, thereby realizing amplification of pulse power, improving average power of pulse laser output by the femtosecond pulse laser, having high pumping absorption efficiency, maintaining single-mode output while having a large mode field diameter, and reducing nonlinear effects, so that output laser maintains high beam quality.

It can be understood that the utility model discloses a with seed/pumping fiber coupler, through the effect of pump light, form high power density in optic fibre, from fibre core output laser, carry out high gain, undistorted enlargies to seed femto second pulse.

Further, in some preferred embodiments, the polarization maintaining fiber is a single mode field photonic crystal fiber with a length of 50-100cm and a mode field diameter of 9.2 ± 0.5 μm.

It can be understood that the adoption of a section of longer full polarization maintaining optical fiber can effectively reduce the adjustment difficulty of the femtosecond pulse laser, simplify the structure of the femtosecond pulse laser, reduce the volume of the laser, reduce the use of space optical devices, improve the long-term stability of the femtosecond pulse laser and be beneficial to realizing batch productization.

In some embodiments, the first active fiber 130 and the second active fiber 160 are doped with gain ions, the gain ions are one or more of neodymium, ytterbium, erbium, thulium, holmium, dysprosium, or praseodymium, the core diameter of the first active fiber 130 is smaller than the core diameter of the second active fiber 160, and the cladding diameter of the first active fiber 130 is larger than the cladding diameter of the second active fiber 160.

In some of these embodiments, the reflectivity of the first bragg grating 150 is equal to or higher than the second bragg grating, which is a regenerative chirped volume bragg grating.

It is understood that the first bragg grating 130 and the second active optical fiber 160 constitute a resonator, the first active optical fiber 130 and the resonator correspond to a seed light oscillation level, and the pump light becomes a seed laser in the first active optical fiber 130 and the resonator.

It is understood that the above parameters can be adjusted according to actual needs.

The femtosecond fiber laser provided by the embodiment of the utility model has a special cavity structure, does not need mechanical adjustment of the light path, can realize the femtosecond fiber laser output with stable output of high average power, and simultaneously ensures the structural simplicity and the circuit safety of the device; the number of optical components can be reduced, the use of passive optical fibers is reduced, the nonlinear effect is inhibited, and the cost is reduced.

Example 2

The utility model also provides an embodiment 1 the working method of femto second fiber laser, including following step:

step S110: the self mode-locked fiber oscillator 110 generates and outputs a first femtosecond pulse laser beam;

step S120: the first femtosecond pulse laser beam enters the pumping module 120 through a polarization maintaining fiber 160 to form pumping light;

step S130: the pump light enters the first active fiber 130 and oscillates in a resonator formed by the first bragg grating 140 and the second bragg grating to form a second femtosecond pulse laser beam;

step S140: the second femtosecond pulse laser beam is transmitted to the amplifier 170 through the second bragg grating to be power-amplified to form a third femtosecond pulse laser beam;

step S150: the third femtosecond pulse laser beam is output to the self-mode-locked fiber oscillator 110, and the self-mode-locked fiber oscillator 110 receives and outputs a femtosecond laser beam of a predetermined energy.

Of course, the femtosecond fiber laser of the present invention can also have various changes and modifications, and is not limited to the specific structure of the above embodiment. In conclusion, the scope of the present invention should include those changes or substitutions and modifications which are obvious to those of ordinary skill in the art.

Claims

1. A femtosecond fiber laser comprising: the self-mode-locking optical fiber oscillator comprises a self-mode-locking optical fiber oscillator, a pumping module, a first active optical fiber, a first Bragg grating, a second active optical fiber, a polarization-maintaining optical fiber and an amplifier, wherein the second Bragg grating is engraved on the cladding of the second active optical fiber; wherein:

2. The femtosecond fiber laser as claimed in claim 1, wherein the self-mode-locked fiber oscillator is an all-fiber oscillator.

3. The femtosecond fiber laser as claimed in claim 1, wherein the pumping module is diode-pumped.

4. The femtosecond fiber laser according to claim 1, wherein the polarization maintaining fiber is a single-mode-field photonic crystal fiber, and the mode field diameter is 9.2 ± 0.5 μm.

5. The femtosecond fiber laser according to claim 1, wherein the first active fiber and the second active fiber are doped with gain ions.

6. A femtosecond fiber laser as claimed in claim 5, wherein the gain ion is one of neodymium, ytterbium, erbium, thulium, holmium, dysprosium, or praseodymium.

7. The femtosecond fiber laser as claimed in claim 6, wherein the core diameters of the first active fiber and the second active fiber are 6.2 ± 0.5 μm, and the mode field diameter is 9.2 ± 0.5 μm.

8. The femtosecond fiber laser according to claim 1, wherein the reflectivity of the first bragg grating is equal to or higher than that of the second bragg grating, and the second bragg grating is a regenerative chirped volume bragg grating.

9. The femtosecond fiber laser of claim 8, wherein the first active fiber core diameter is smaller than the core diameter of the second active fiber, and the first active fiber cladding diameter is larger than the cladding diameter of the second active fiber.

10. The femtosecond fiber laser as claimed in claim 1, wherein the wavelength of the first femtosecond pulse laser beam is 1030nm ± 5nm, the pulse width is less than 500fs, the pulse frequency is 100-.