CN217036309U

CN217036309U - Ultrafast seed source for high-power optical fiber laser amplification

Info

Publication number: CN217036309U
Application number: CN202220800908.0U
Authority: CN
Inventors: 于振华; 邓明发; 孙维娜; 许昌兴
Original assignee: Beijing Oriental Sharp Laser Technology Co ltd
Current assignee: Beijing Oriental Sharp Laser Technology Co ltd
Priority date: 2022-04-08
Filing date: 2022-04-08
Publication date: 2022-07-22
Anticipated expiration: 2032-04-08

Abstract

The utility model provides an ultrafast seed source for high-power optical fiber laser amplification, which comprises a high repetition frequency ultrafast laser, a dispersion broadening module, a repetition frequency multiplication module and an output head, wherein the high repetition frequency ultrafast laser, the dispersion broadening module, the repetition frequency multiplication module and the output head are sequentially connected through optical fibers, the high repetition frequency ultrafast laser is used for emitting seed source laser, the dispersion broadening module is used for broadening the spectral width of the seed source laser, and the repetition frequency multiplication module is used for increasing the number of spectral longitudinal modes of the seed source laser. The utility model increases the spectrum longitudinal mode component of the seed source by widening the spectrum of the seed source, thereby reducing the Raman effect in the laser.

Description

Ultrafast seed source for high-power optical fiber laser amplification

Technical Field

The utility model belongs to the field of ultrafast seed sources, and particularly relates to an ultrafast seed source for high-power optical fiber laser amplification.

Background

With the rapid development of laser technology, laser light sources have been applied to various industries in the society. The high-power optical fiber laser is widely applied to the fields of laser cutting, laser welding, national defense and the like. For high power fiber lasers, raman effects occur in the laser when the energy in the fiber reaches a certain threshold. Namely: the energy of the laser is transferred to the Raman peak from the original wavelength of the laser, so that the original wavelength energy of the laser is reduced. The raman effect is one of the main factors limiting the energy boost of high power fiber lasers.

A typical high power fiber laser optical path diagram, as shown in fig. 1, generally includes a seed source and a primary fiber amplifier. Methods commonly employed to reduce the raman effect of a system are: the Raman filtering inclined grating is added after the diameter of the optical fiber core is increased, the length of the optical fiber and the seed source are shortened. The threshold for the raman effect is proportional to the fiber core diameter and inversely proportional to the fiber length. The conventional method of suppressing the raman effect is to increase the core diameter of the optical fiber while shortening the length of the optical fiber. However, the core diameter of the optical fiber cannot be increased infinitely in the laser because the increase of the core diameter or the generation of high-order modes in the optical fiber results in the deterioration of the laser beam quality. The reduction of the length of the optical fiber is also limited by the influence of the length of the pigtail of the optical fiber device and the absorption of the gain optical fiber. The raman filtering tilt grating can filter out raman components in the seed light, can provide a seed with a purer spectrum for the amplifier, but cannot limit the raman effect generated by the amplifier, so that the effect is limited.

Disclosure of Invention

Aiming at the technical problems in the prior art, the utility model provides an ultrafast seed source for high-power optical fiber laser amplification, and the spectrum of the seed source is widened to increase the spectrum longitudinal mode components of the seed source, so that the Raman effect in a laser is reduced.

The technical scheme adopted by the utility model is as follows: the utility model provides an ultrafast kind of source for high power fiber laser enlargies, includes high repetition frequency ultrafast laser, dispersion broadening module, repetition frequency multiplication module and output head, high repetition frequency ultrafast laser, dispersion broadening module, repetition frequency multiplication module and output head loop through the fiber connection, high repetition frequency ultrafast laser is used for sending kind of source laser, dispersion broadening module is used for widening the spectral width of kind of source laser, repetition frequency multiplication module is used for increasing the spectrum longitudinal mode quantity of kind of source laser.

Further, the dispersion broadening module is a dispersion element.

Further, the dispersion broadening module adopts a grating.

Furthermore, the repetition frequency multiplication module comprises an optical fiber beam splitter and an optical fiber beam combiner, and the optical fiber beam splitter and the optical fiber beam combiner are connected through a plurality of optical fibers with different lengths.

The working principle is as follows: the utility model fully analyzes the mechanism of Raman generation based on the physical essence of Raman effect. It is proposed to increase the raman threshold of the laser by broadening the spectral width of the seed source and increasing the number of longitudinal modes of the spectrum. The adopted broad spectrum seed is an ultrafast laser, the spectral width of the ultrafast laser is several times to more than ten times wider than that of a conventional laser, the number of longitudinal modes is much larger than that of the conventional laser, and the Raman threshold of the laser can be greatly improved by the mode.

Compared with the prior art, the utility model has the following beneficial effects: the utility model adopts an ultrafast laser as a seed source, and the ultrafast laser has the characteristics of wide spectrum and multiple longitudinal modes; then, the ultrafast laser is subjected to dispersion delay, laser pulses are broadened, and the pulsed light is changed into continuous light through repetition frequency multiplication; finally, the high-quality laser seed source with wide spectrum and multiple longitudinal modes is obtained. When the high-power laser amplification is carried out by using the sub-source, the Raman effect can be effectively inhibited. The utility model improves the Raman threshold of the laser by widening the spectrum width of the seed source and increasing the number of the longitudinal modes of the spectrum, and breaks through the limitation of the traditional technical means.

Drawings

FIG. 1 is a diagram of an exemplary high power fiber laser optical path;

FIG. 2 is a schematic structural diagram of an embodiment of the present invention;

fig. 3 is a schematic diagram of the time domain evolution of the pulse according to the embodiment of the present invention.

In the figure, the laser comprises a high repetition frequency ultrafast laser, a 2-dispersion broadening module, a 3-repetition frequency multiplication module and a 4-output head.

Detailed Description

In order to make the technical solutions of the present invention better understood, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

The embodiment of the utility model provides an ultrafast seed source for high-power optical fiber laser amplification, which comprises a high-repetition-frequency ultrafast laser 1, a dispersion broadening module 2, a repetition-frequency multiplying module 3 and an output head 4, wherein the high-repetition-frequency ultrafast laser 1, the dispersion broadening module 2, the repetition-frequency multiplying module 3 and the output head 4 are sequentially connected through optical fibers. The high repetition frequency ultrafast laser 1 is used for emitting seed source laser, the dispersion broadening module 2 is used for broadening the spectral width of the seed source laser, and the repetition frequency multiplication module 3 is used for increasing the number of the spectral longitudinal modes of the seed source laser. The dispersion broadening module 2 is a dispersion element, and a grating is adopted in common use. The repetition frequency multiplication module 3 comprises an optical fiber beam splitter and an optical fiber beam combiner, and the optical fiber beam splitter and the optical fiber beam combiner are connected through a plurality of optical fibers with different lengths.

The time domain evolution of the laser pulse during the operation of the embodiment is shown in fig. 3, and the high repetition frequency ultrafast laser 1 generates a broad spectrum high repetition frequency laser pulse; when the laser pulse passes through the dispersion broadening module 2, the transmission speeds of the front edge and the rear edge of the spectrum affected by dispersion are different, so that the pulse broadening is caused; then the broadened laser pulses pass through the repetition frequency multiplication module 3, the repetition frequency of the laser is further increased, finally the front edges and the rear edges of the adjacent pulses are overlapped together, and the laser is changed into continuous laser from pulse light and is output by an output head 4.

In this embodiment, the laser is changed into three laser beams through the optical fiber beam splitter, the time domains of the three laser beams sequentially differ by one-third period by adjusting the optical path difference of the three laser beams, and then the three laser beams are combined into one laser beam through the optical fiber beam combiner, where the repetition frequency of the newly combined laser beam is three times that of the original laser beam. According to the actual use requirement, any repetition frequency multiplication module 3 can be manufactured through a device consisting of a plurality of optical fiber beam splitters and optical fiber beam combiners.

The present invention has been described in detail with reference to the embodiments, but the description is only illustrative of the present invention and should not be construed as limiting the scope of the utility model. The scope of protection of the utility model is defined by the claims. The technical solutions of the present invention or those skilled in the art, based on the teaching of the technical solutions of the present invention, should be considered to be within the scope of the present invention, and all equivalent changes and modifications made within the scope of the present invention or equivalent technical solutions designed to achieve the above technical effects are also within the scope of the present invention.

Claims

1. An ultrafast seed source for high power fiber laser amplification, characterized by: the high repetition frequency ultrafast laser, the dispersion broadening module, the repetition frequency multiplying module and the output head are connected through optical fibers in sequence, the high repetition frequency ultrafast laser is used for emitting seed source laser, the dispersion broadening module is used for broadening the spectral width of the seed source laser, and the repetition frequency multiplying module is used for increasing the number of longitudinal spectral modes of the seed source laser.

2. The ultrafast seed source for high power fiber laser amplification of claim 1, wherein: the dispersion broadening module is a dispersion element.

3. The ultrafast seed source for high power fiber laser amplification of claim 2, wherein: the dispersion broadening module adopts a grating.

4. The ultrafast seed source for high power fiber laser amplification of claim 1, wherein: the repetition frequency multiplication module comprises an optical fiber beam splitter and an optical fiber beam combiner, and the optical fiber beam splitter and the optical fiber beam combiner are connected through a plurality of optical fibers with different lengths.