A fiber femtosecond laser oscillator

Abstract

The fiber femtosecond laser oscillator provided by the present application comprises a pump laser (6) and a pump laser (7) which respectively pump the corresponding first optical fiber (2) and the second optical fiber (3) to generate output light with a wide spectrum. The output light passes through a dispersion control device (4) which adjusts the output light into a multi-wavelength light beam which is linearly distributed in space. The multi-wavelength light beam passes through a reflective end mirror (5) to perform spectrum screening on the output light again. The light beam after spectrum screening is then transmitted to the mode-locking device (1) through the dispersion control device (4), the second optical fiber (3) and the first optical fiber (2) in sequence. The mode-locking device (1) then fixes the phase relationship of the output light, compresses the pulse width and emits a light pulse of the femtosecond order. The fiber femtosecond laser oscillator provided by the present application broadens the gain bandwidth of the femtosecond laser oscillator by adding a new gain medium in the oscillator, so that the output femtosecond laser pulse with a wider spectrum and narrower pulse width is output.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a fiber femtosecond laser oscillator. Background Art

[0002] High-power fiber femtosecond lasers are widely used in micro-nano processing, biomedicine, scientific research, and national defense. At present, the main components of mainstream high-power fiber femtosecond lasers include: fiber femtosecond laser oscillator, spectrum broadening part, high-power laser amplification part, and spectrum compression part. Among them, the fiber laser oscillator provides seed pulses for the entire laser system and is one of the core parts of the entire system. Its output characteristics determine the performance indicators of the laser system, such as pulse quality and stability. The spectral width output by the fiber laser oscillator directly determines the spectral evolution during the amplification process and ultimately determines the pulse width after compression. Therefore, it is very important for high-power fiber femtosecond lasers to adopt new technologies to increase the spectral width output by the fiber laser oscillator.

[0003] The current mainstream high-power fiber femtosecond laser oscillators mainly use the nonlinear mode locking technology of a single doped fiber to compress the pulse width to achieve high-energy, wide-spectrum ultrashort pulse lasers. The existing mainstream fiber femtosecond laser oscillators have the following shortcomings:

[0004] 1. The oscillator fiber generally uses a single doped fiber. Due to the limitation of gain bandwidth, the spectral width of the oscillator output is narrow and the pulse width is relatively wide;

[0005] 2. Although the nonlinear method can increase the output spectrum width of the femtosecond laser oscillator, under this condition, the dispersion, gain, loss and other parameters need to be precisely modulated, the mode locking is unstable, and the output pulse width has jumps, which increases the system complexity and reduces the working reliability. Summary of the invention

[0006] In view of this, it is necessary to provide a fiber femtosecond laser oscillator with high energy, wide spectrum and high stability to address the defects in the prior art.

[0007] To solve the above problems, this application adopts the following technical solutions:

[0008] The present application provides a fiber femtosecond laser oscillator, comprising a mode-locking device (1), a first optical fiber (2), a second optical fiber (3), a dispersion control device (4), a reflective end mirror (5), a first pump laser (6) and a second pump laser (7), wherein the first pump laser (6) and the second pump laser (7) respectively pump the first optical fiber (2) and the second optical fiber (3), wherein:

[0009] The pump laser (6) and the pump laser (7) respectively pump the first optical fiber (2) and the second optical fiber (3) corresponding to each other to generate output light with a wide spectrum. The output light is adjusted to a multi-wavelength light beam linearly distributed in space by the dispersion control device (4). The multi-wavelength light beam is then subjected to spectrum screening again after passing through the reflective end mirror (5). The light beam after spectrum screening is then transmitted to the mode-locking device (1) in sequence through the dispersion control device (4), the second optical fiber (3) and the first optical fiber (2). The mode-locking device (1) then fixes the phase relationship of the output light, compresses the pulse width, and outputs a light pulse of the order of femtoseconds.

[0010] In some embodiments, the first optical fiber (2) is doped with Yb, and the second optical fiber (3) is doped with Nd.

[0011] In some embodiments, the first optical fiber (2) and the second optical fiber (3) are fused together.

[0012] In some embodiments, the pump laser (6) and the pump laser (7) have different wavelengths.

[0013] This application adopts the above technical solution, and its beneficial effects are as follows:

[0014] The fiber femtosecond laser oscillator provided by the present application comprises the pump laser (6) and the pump laser (7) respectively pumping the corresponding first optical fiber (2) and the second optical fiber (3) to generate output light with a wide spectrum, the output light is adjusted to a multi-wavelength light beam linearly distributed in space by the dispersion control device (4), the multi-wavelength light beam is then passed through the reflective end mirror (5) to perform spectral screening on the output light again, the light beam after spectral screening is then transmitted to the mode-locking device (1) in sequence through the dispersion control device (4), the second optical fiber (3) and the first optical fiber (2), and the mode-locking device (1) fixes the phase relationship of the output light, compresses the pulse width, and outputs a light pulse of the femtosecond order. The fiber femtosecond laser oscillator provided by the present application broadens the gain bandwidth of the femtosecond laser oscillator by adding a new gain medium in the oscillator, so that the output femtosecond laser pulse with a wider spectrum and narrower pulse width is output.

[0015] In addition, the fiber femtosecond laser oscillator provided by the present application, in the laser oscillator, the ytterbium (Yb)-doped fiber and the neodymium (Nd)-doped fiber are fused together by welding, and the two optical fibers are pumped by corresponding pump sources of different wavelengths, combined with mode locking technology and dispersion control devices, thereby achieving wide spectrum, narrow pulse width laser pulse output. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the structure of the fiber femtosecond laser oscillator provided in this application. DETAILED DESCRIPTION

[0018] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0019] In the description of the present application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0022] See also Figure 1 , is a schematic structural diagram of a fiber femtosecond laser oscillator provided in an embodiment of the present application, comprising: a mode-locking device (1), a first optical fiber (2), a second optical fiber (3), a dispersion control device (4), a reflective end mirror (5), a first pump laser (6) and a second pump laser (7), wherein the first pump laser (6) and the second pump laser (7) respectively pump the first optical fiber (2) and the second optical fiber (3).

[0023] The fiber femtosecond laser oscillator provided in this application works as follows:

[0024] The pump laser (6) and the pump laser (7) respectively pump the first optical fiber (2) and the second optical fiber (3) corresponding to each other to generate output light with a wide spectrum. The output light is adjusted to a multi-wavelength light beam linearly distributed in space by the dispersion control device (4). The multi-wavelength light beam is then subjected to spectrum screening again after passing through the reflective end mirror (5). The light beam after spectrum screening is then transmitted to the mode-locking device (1) in sequence through the dispersion control device (4), the second optical fiber (3) and the first optical fiber (2). The mode-locking device (1) then fixes the phase relationship of the output light, compresses the pulse width, and outputs a light pulse of the order of femtoseconds.

[0025] In some embodiments, the first optical fiber (2) is doped with Yb, and the second optical fiber (3) is doped with Nd.

[0026] In some embodiments, the first optical fiber (2) and the second optical fiber (3) are fused together.

[0027] It can be understood that fusing two sections of optical fiber doped with ytterbium (Yb) and neodymium (Nd) as a new gain medium has better optical properties than a single quartz fiber. By pumping them separately, it has good power stability, a wider spectrum width and a narrower pulse width. And by performing segmented pumping on the two sections of optical fiber doped with different elements that are fused together, it is easier to achieve wide-spectrum laser output.

[0028] In some embodiments, the pump laser (6) and the pump laser (7) have different wavelengths.

[0029] It can be understood that the present application uses corresponding pump sources of different wavelengths to pump the two optical fibers, combined with mode locking technology and dispersion control devices, to achieve wide spectrum, narrow pulse width laser pulse output.

[0030] The fiber femtosecond laser oscillator provided in the present application broadens the gain bandwidth of the femtosecond laser oscillator by adding a new gain medium in the oscillator, so that the output of the femtosecond laser pulse has a wider spectrum and a narrower pulse width.

[0031] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A fiber femtosecond laser oscillator, characterized in that: The invention comprises a mode-locking device (1), a first optical fiber (2), a second optical fiber (3), a dispersion control device (4), a reflective end mirror (5), a first pump laser (6) and a second pump laser (7), wherein the first pump laser (6) and the second pump laser (7) respectively pump the first optical fiber (2) and the second optical fiber (3), wherein: The pump laser (6) and the pump laser (7) respectively pump the corresponding first optical fiber (2) and the second optical fiber (3) to generate output light with a wide spectrum. The output light is adjusted to a multi-wavelength light beam linearly distributed in space by the dispersion control device (4). The multi-wavelength light beam is then subjected to spectral screening again after passing through the reflective end mirror (5). The spectrally screened light beam is then transmitted to the mode-locking device (1) in sequence through the dispersion control device (4), the second optical fiber (3) and the first optical fiber (2). The mode-locking device (1) then fixes the phase relationship of the output light and compresses the pulse width to obtain a light pulse of the order of femtoseconds. The first optical fiber (2) is doped with Yb, the second optical fiber (3) is doped with Nd, and the first pump laser (6) and the second pump laser (7) have different wavelengths.

2. The fiber femtosecond laser oscillator according to claim 1, characterized in that: The first optical fiber (2) and the second optical fiber (3) are fused together.

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