Non-polarization-maintaining fiber laser system

Abstract

The utility model belongs to the technical field of non-polarization-maintaining lasers, and particularly relates to a non-polarization-maintaining fiber laser system. According to the non-polarization-maintaining optical fiber laser system, light output by the non-polarization-maintaining optical fiber laser serves as infrared fundamental frequency light (which can be continuous or pulse) and is transmitted to the laser head through the optical fiber, a second harmonic crystal can be arranged in the laser head, and infrared light is converted into green light to be output through the second harmonic crystal; a second harmonic crystal and a third harmonic crystal can also be integrated in the laser head, the second harmonic crystal converts the infrared light into green light, then the infrared light and the green light are mixed and enter the third harmonic crystal for sum frequency action, and ultraviolet output is obtained. In addition, flexible movement in an actual application scene is facilitated through optical fiber transmission, and the laser output head is integrated with a nonlinear crystal and can directly output green light or ultraviolet light.

Description

Technical Field

[0001] This invention belongs to the field of non-polarization-maintaining laser technology, specifically relating to a non-polarization-maintaining fiber laser system. Background Technology

[0002] The main difference between polarization-maintaining lasers and non-polarization-maintaining lasers lies in their light polarization state. Polarization-maintaining lasers output linearly polarized light, while non-polarization-maintaining lasers output randomly polarized light. Polarization-maintaining lasers use polarizers and modulators to polarize the light, ensuring a consistent polarization state for the output light. Non-polarization-maintaining lasers, on the other hand, do not require these devices and can directly output randomly polarized light.

[0003] Non-polarization-maintaining fiber lasers are mature, reliable, and low-cost, but they generally output in the infrared band, limiting their applications. To achieve short-wavelength output, the conventional approach is to use a polarization-maintaining fiber laser with external cavity frequency doubling technology, but polarization-maintaining fibers are expensive and relatively difficult to manufacture. Utility Model Content

[0004] The purpose of this invention is to provide a non-polarization-maintaining fiber laser system to solve the technical problem of high cost when using polarization-maintaining fiber lasers to achieve short-wavelength output.

[0005] This application provides a non-polarization-maintaining fiber laser system, comprising: a non-polarization-maintaining laser, an optical fiber, and a laser output head connected in sequence; wherein the laser output head comprises: an optical fiber collimator, a focusing lens, a second harmonic crystal, a dichroic mirror, and a window mirror arranged in sequence.

[0006] In one embodiment of this application, the laser output head further includes a third harmonic crystal disposed between the second harmonic crystal and the dichroic mirror.

[0007] In one embodiment of this application, the linewidth of the laser spectrum output by the non-polarization-maintaining laser is no greater than 1 nm.

[0008] In one embodiment of this application, the window mirror is a focusing lens or a planar window.

[0009] In one embodiment of this application, the laser output head further includes a light absorber disposed on one side of the dichroic mirror.

[0010] In one embodiment of this application, the non-polarization-maintaining fiber laser system further includes: a control module; the non-polarization-maintaining laser is electrically connected to the control module; a light-collecting mirror is disposed between a dichroic mirror and a window mirror; a power probe is electrically connected to the control module and is used to receive the light beam reflected by the light-collecting mirror; the control module is used to adjust the output power of the non-polarization-maintaining laser according to the beam power obtained by the power probe.

[0011] The beneficial effects of this utility model are:

[0012] This invention relates to a non-polarization-maintaining fiber laser system. The output light from a non-polarization-maintaining fiber laser is used as the infrared fundamental frequency light (which can be continuous or pulsed) and transmitted to a laser head via optical fiber. The laser head can contain a second-harmonic generation crystal, which converts the infrared light into green light for output. Alternatively, the laser head can integrate both a second-harmonic generation crystal and a third-harmonic generation crystal. The second-harmonic generation crystal converts the infrared light into green light, and then the infrared and green light are mixed and fed into the third-harmonic generation crystal for sum-frequency interaction, resulting in ultraviolet output. Furthermore, fiber optic transmission facilitates flexible movement in practical applications, and the laser output head integrates a nonlinear crystal that can directly output green or ultraviolet light.

[0013] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and the accompanying drawings.

[0014] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a preferred embodiment of the non-polarization-maintaining fiber laser system of the present invention;

[0017] Figure 2 This is a schematic diagram of a laser output head according to a preferred embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of a laser output head according to another preferred embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of a laser output head according to another preferred embodiment of the present invention.

[0020] In the picture:

[0021] 1. Fiber collimator; 2. Focusing lens; 3. Second harmonic crystal; 4. Third harmonic crystal; 5. Dichroic mirror; 6. Light absorber; 7. Window mirror; 8. Light collection mirror; 9. Power probe. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] This application provides a non-polarization-maintaining fiber laser system, which will be described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0024] See Figure 1 In one embodiment, the non-polarization-maintaining fiber laser system includes: a non-polarization-maintaining laser, an optical fiber, and a laser output head connected in sequence.

[0025] In this embodiment, the output light of the non-polarization-maintaining fiber laser is used as the infrared fundamental frequency light (which can be continuous or pulsed) and transmitted to the laser head through an optical fiber. Optical fiber transmission facilitates flexible movement in practical application scenarios. The laser output head can integrate a nonlinear crystal that can directly output green or ultraviolet light. For example, a second harmonic crystal can be installed inside the laser head, which converts infrared light into green light for output. Alternatively, a second harmonic crystal and a third harmonic crystal can be integrated inside the laser head. The second harmonic crystal converts infrared light into green light, and then the infrared and green light are mixed and fed into the third harmonic crystal for sum-frequency interaction to obtain ultraviolet output.

[0026] See Figure 2 Specifically, in one embodiment, the laser output head includes: an optical fiber collimator 1, a focusing lens 2, a second harmonic crystal 3, a dichroic mirror 5, and a window mirror 7 arranged sequentially.

[0027] In this embodiment, the fiber collimator 1 can be connected to the end of the fiber, so that the infrared light output by the fiber is a collimated beam; the beam passes through the lens 2 and is focused into the second harmonic crystal 3, which converts part of the infrared light into green light; the dichroic mirror 5 reflects the remaining infrared light, and the green light is transmitted through the dichroic mirror 5 and finally output from the window mirror 7.

[0028] See Figure 3 Furthermore, in one embodiment, the laser output head further includes a third harmonic crystal 4 disposed between the second harmonic crystal 3 and the dichroic mirror 5.

[0029] Specifically, the fiber collimator 1 can be connected to the end of the fiber, so that the infrared light output by the fiber is a collimated beam; the beam passes through the lens 2 and is focused into the second harmonic crystal 3 and the third harmonic crystal 4. The second harmonic crystal 3 converts part of the infrared light into green light, and the third harmonic crystal 4 makes the infrared light and green light combine to obtain ultraviolet light. The dichroic mirror 5 reflects the remaining infrared light and green light, and the ultraviolet light is transmitted through the dichroic mirror 5 and finally output from the window mirror 7.

[0030] In one embodiment, the laser output head further includes a light absorber 6 disposed on one side of the dichroic mirror 5 for absorbing the light reflected by the dichroic mirror 5.

[0031] In one embodiment, preferably, in order to improve the conversion efficiency of the second harmonic crystal 3 and / or the third harmonic crystal 43, the linewidth of the laser spectrum output by the non-polarization-maintaining laser should be as narrow as possible, which may be no greater than 1 nm.

[0032] Optionally, the window mirror 7 can be a flat window to seal and protect the internal optical path of the laser output head; or it can be a focusing lens to both seal and protect the output beam and converge it onto the processing surface.

[0033] Further, see Figure 4 To improve the power stability of the final output of the laser head, the non-polarization-maintaining fiber laser system may further include: a control module; the non-polarization-maintaining laser is electrically connected to the control module; a light-collecting mirror 8, disposed between the dichroic mirror 5 and the window mirror 7; a power probe 9, electrically connected to the control module, for receiving the light beam reflected by the light-collecting mirror 8; the control module is used to adjust the output power of the non-polarization-maintaining laser according to the beam power obtained by the power probe 9.

[0034] In this embodiment, by adding a light-collecting mirror 8 inside the laser output head, a small portion of the beam is reflected into the power probe 9 to monitor the power in real time. The power is then fed back to the control module via a signal line to synchronously adjust the power control factor of the non-polarization-maintaining laser, such as parameters like current, so that the final output power of the laser output head is stabilized at the set value. This can overcome the problem of the output polarization ratio of the non-polarization-maintaining fiber laser changing over time.

[0035] It should be noted that all the devices (parts whose specific structures are not specified) selected in this application are general standard parts or parts known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0036] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A non-polarization-maintaining fiber laser system, characterized in that, include: A non-polarization-maintaining laser, an optical fiber, and a laser output head are connected in sequence. in The laser output head includes, in sequence, an optical fiber collimator (1), a focusing lens (2), a second harmonic crystal (3), a dichroic mirror (5), and a window mirror (7).

2. The non-polarization-maintaining fiber laser system according to claim 1, characterized in that, The laser output head also includes a third harmonic crystal (4) disposed between the second harmonic crystal (3) and the dichroic mirror (5).

3. The non-polarization-maintaining fiber laser system according to claim 1 or 2, characterized in that, The linewidth of the laser spectrum output by the non-polarization-maintaining laser is no greater than 1 nm.

4. The non-polarization-maintaining fiber laser system according to claim 1, characterized in that, The window mirror (7) is a focusing lens or a planar window.

5. The non-polarization-maintaining fiber laser system according to claim 1, characterized in that, The laser output head also includes a light absorber (6) disposed on one side of the dichroic mirror (5).

6. The non-polarization-maintaining fiber laser system according to claim 1, characterized in that, The non-polarization-maintaining fiber laser system also includes: Control module; the non-polarization-maintaining laser is electrically connected to the control module; A light-collecting mirror (8) is set between the dichroic mirror (5) and the window mirror (7); The power probe (9) is electrically connected to a control module and is used to receive the light beam reflected by the light-collecting mirror (8); The control module is used to adjust the output power of the non-polarization-maintaining laser based on the beam power obtained by the power probe (9).

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