Mamyshev mode-locked skyrmion fiber laser

Abstract

This application discloses a Mamyshev mode-locked skyrmion fiber laser, comprising: a ring-cavity Mamyshev oscillator, the ring-cavity Mamyshev oscillator including a first arm and a second arm connected in a ring; and a skyrmion generation module, the skyrmion generation module including a first polarization beam splitter, a mode converter, a beam splitter, and a coupler; wherein, the Gaussian beam output from the second arm is connected to the first polarization beam splitter, one output beam of the first polarization beam splitter is connected to the mode converter, and the other output beam is connected to the beam splitter, and the Laguerre-Gaussian (LG) beams of different modes and polarization directions output by the mode converter and the beam splitter are respectively connected to the coupler, thereby coherently superimposing two orthogonally polarized LG mode beams, and after adjusting the polarization direction by a quarter-wave plate, ultrafast Stokes vector optical skyrmions with different structural types and high beam quality can be output.

Description

Technical Field

[0001] The present application relates to the technical field of ultrafast optics and light field control, and to a Mamyshev mode-locked skyrmion fiber laser. Background Art

[0002] Skyrmions have been shown to be quasiparticles carrying topological spin structures in both nuclear physics and magnetic materials. Their structures are topologically protected and cannot be changed by continuous deformation. They can be used in logic devices, transistors, quantum computing and other fields.

[0003] In recent years, with the vigorous development of topological optics, optical skyrmions have been proposed and have aroused widespread interest among researchers in the field of topological optics and light field control. As a result, optical skyrmions with different topological structures and different vector configurations continue to emerge, providing new ideas and methods for the study of the spatiotemporal characteristics of topological light fields.

[0004] The study of skyrmions in optical fields began with the evanescent field in the lattice structure and the focus of orbital angular momentum and vector beams. Due to its small size, high stability, and diverse topological structures, optical skyrmions have potential application value in high-resolution polarization imaging, high-density optical information storage, and high-precision displacement sensing.

[0005] Optical skyrmions can be generated in two ways: active and passive. Passive methods mainly use external conversion technologies such as pure phase spatial light modulators (SLMs), GRIN lens arrays, and surface plasmons to generate optical skyrmions. However, these methods have limited power handling and wavelength compatibility, and the conversion efficiency is also very uncertain.

[0006] In addition to external conversion methods, the direct generation of structured light in the laser cavity has also been a hot topic in recent years. As time goes by, the complexity of field generation continues to increase. At present, although the skyrmion laser based on the wedge plate shearing interferometer has successfully realized the Bloch skyrmion, Nell skyrmion and anti-skyrmion in the solid cavity. However, although this laser has a compact structure, it can only work in the visible light band in the form of continuous light and cannot generate infrared bands and high-energy ultrafast skyrmions.

[0007] In addition, in recent years, mode-locked fiber lasers based on saturable absorbers (SAs) can directly generate ultrafast vector beams and vortex beams in the cavity. However, in these laser configurations, the obtained pulse output energy and peak power are still limited due to the poor tolerance to nonlinear phase shift, and pulse splitting is often caused.

[0008] In summary, there is no solution in the prior art that can directly generate high-energy ultrafast skyrmions in the fiber laser cavity, which does not meet the growing needs of optical communications and high-power practical applications. Summary of the invention

[0009] The present application provides a Mamyshev mode-locked skyrmion fiber laser that can output Stokes vector optical skyrmions of different structural types and with high beam quality, aiming to solve the prior art problems mentioned in the background technology.

[0010] In one embodiment, a Mamyshev mode-locked skyrmion fiber laser is provided, comprising:

[0011] A ring cavity Mamyshev oscillator, the ring cavity Mamyshev oscillator comprising a first arm and a second arm connected in a ring shape; and

[0012] A skyrmion generation module, the skyrmion generation module comprising a first polarization beam splitter, a mode conversion element, a beam splitter, a coupler and a first quarter wave plate;

[0013] The Gaussian beam output by the second arm is connected to the first polarization beam splitter, and an output beam of the first polarization beam splitter is connected to the mode conversion element, and then converted into a linear polarization state LG by the mode conversion element. 01 Modulus Gaussian beam;

[0014] Another output beam of the first polarization beam splitter is connected to the beam splitter, and the transmitted beam of the beam splitter is connected to the input end of the first arm; the reflected light output by the beam splitter is in the linear polarization state LG 00 mode Gaussian beam and the LG 01 The modes of the Gaussian beams have orthogonal polarization directions;

[0015] The mode conversion element outputs the LG 01 mode Gaussian beam with the LG output of the beam splitter 00 The modulus Gaussian beams are connected to the couplers respectively, so as to be coherently superimposed through the couplers, and the optical skyrmions are formed after the polarization directions are adjusted by the 1 / 4 wave plate.

[0016] In one embodiment, the Mamyshev mode-locked skyrmion fiber laser further comprises:

[0017] First 1 / 2 wave plate;

[0018] The first 1 / 2 wave plate is arranged between the mode conversion element and the coupler, and the LG output by the mode conversion element after conversion 01 The Gaussian beam has its polarization direction converted by the first 1 / 2 wave plate.

[0019] In one embodiment, the Mamyshev mode-locked skyrmion fiber laser further comprises:

[0020] A second 1 / 2 wave plate, the second 1 / 2 wave plate is arranged between the first polarization beam splitter and the beam splitter;

[0021] Wherein, an output light beam of the first polarization beam splitter enters the beam splitter after the polarization direction is adjusted by the second 1 / 2 wave plate.

[0022] In one embodiment, the Mamyshev mode-locked skyrmion fiber laser further comprises:

[0023] A reflector is disposed on the optical path between the beam splitter and the coupler, and the reflected light output by the beam splitter is transmitted to the coupler after the direction is adjusted by the reflector.

[0024] In one embodiment, the mode conversion element is an S-Plate geometric phase retarder.

[0025] In one embodiment, the first arm includes a first pump signal combiner, a first gain fiber, a first fiber collimator with a pigtail, a second 1 / 4 wave plate, a third 1 / 2 wave plate, a second polarization beam splitter, a first polarization-dependent isolator, a fourth 1 / 2 wave plate, and a first blazed grating, which are connected in sequence; and

[0026] a first pump source and a second fiber collimator;

[0027] The first pump source and the second fiber collimator are respectively connected to the input end of the first pump signal combiner, and the output end of the first blazed grating is connected to the input end of the second arm.

[0028] In one embodiment, the second arm includes a second pump signal combiner, a second gain fiber, and a third fiber collimator with a pigtail, which are connected in sequence;

[0029] A second polarization-dependent isolator, a fifth 1 / 2 wave plate, and a second blazed grating connected in sequence; and

[0030] a second pump source and a fourth fiber collimator;

[0031] The second pump source and the fourth fiber collimator are respectively connected to the input end of the second pump signal combiner, the output end of the first blazed grating is connected to the input end of the fourth fiber collimator, the output beam of the third fiber collimator is connected to the first polarization beam splitter, the transmitted beam output by the beam splitter is connected to the second polarization-dependent isolator, and the output end of the second blazed grating is connected to the input end of the second fiber collimator.

[0032] In one embodiment, a third quarter wave plate is disposed between the second blazed grating and the first pump signal combiner;

[0033] The second blazed grating output light beam enters the input end of the first pump signal combiner after the polarization direction is adjusted by the third 1 / 4 wave plate.

[0034] In one embodiment, the first pump source and the second pump source are both 976 nm multi-mode high-power pump sources.

[0035] In one embodiment, the first gain fiber and the second gain fiber are double-clad ytterbium-doped fibers.

[0036] Beneficial effects of this application:

[0037] The laser provided in this application can directly output ultrafast Stokes vector optical skyrmions of different structural types and with high beam quality in the cavity, providing a new solution for practical application needs and research on the generation of complex intracavity structured light fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments 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 creative labor.

[0039] Figure 1 Schematic diagram of the principle of a Mamyshev mode-locked skyrmion fiber laser in one embodiment of the present application;

[0040] Figure 2 is a schematic diagram of the structure of a skyrmion generation module in an embodiment of the present application;

[0041] Reference numerals in the figures:

[0042] First arm 1;

[0043] A first pump source 101; a first pump signal combiner 102; a first gain fiber 103; a first fiber collimator 104; a second 1 / 4 wave plate 105; a third 1 / 2 wave plate 106; a second polarization beam splitter 107; a first polarization-dependent isolator 108; a fourth 1 / 2 wave plate 109; a first blazed grating 110; and a second fiber collimator 111.

[0044] Second arm 2;

[0045] A second pump source 201; a second pump signal combiner 202; a second gain fiber 203; a third fiber collimator 204; a second polarization-dependent isolator 208; a fifth 1 / 2 wave plate 209; a second blazed grating 210; a third 1 / 4 wave plate 211; and a fourth fiber collimator 212.

[0046] Skyrmion generation module 3;

[0047] A first polarization beam splitter 301 ; a mode conversion element 302 ; a first 1 / 2 wave plate 303 ; a second 1 / 2 wave plate 304 ; a beam splitter 305 ; a reflector 306 ; a coupler 307 ; and a first 1 / 4 wave plate 308 . DETAILED DESCRIPTION

[0048] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0049] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0050] 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0053] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0054] The study found that in a paraxial light beam, the polarization state of the electromagnetic field when propagating in free space is always perpendicular to the propagation direction of the light beam, that is, the transverse polarization state distribution. Therefore, it is difficult to construct a three-dimensional vector field structure in free space, that is, it is difficult to construct a Stokes optical vector skyrmion.

[0055] In order to construct Stokes optical vector skyrmions, the existing lasers have skyrmion lasers such as wedge-plate shearing interferometers, which have successfully realized Bloch skyrmions, Nell skyrmions and anti-skyrmions in solid cavities. However, although this laser has a compact structure, it can only work in the visible light band in the form of continuous light, which is not enough to meet the practical application needs of high-energy ultrafast skyrmion lasers in different bands in the future.

[0056] Another example is mode-locked fiber lasers based on saturable absorbers (SAs), which can directly generate ultrafast vector beams and vortex beams in the cavity. However, in these laser configurations, due to the poor tolerance to nonlinear phase shift, the obtained pulse output energy and peak power are still limited, and pulse splitting is often caused.

[0057] Based on this, the present application provides the following embodiments after research.

[0058] In some embodiments, see Figure 1 and Figure 2 , provides a Mamyshev mode-locked skyrmion fiber laser, comprising:

[0059] A ring cavity Mamyshev oscillator (Mamishev oscillator), the ring cavity Mamyshev oscillator comprises a first arm 1 and a second arm 2 connected in a ring shape; and

[0060] The skyrmion generation module 3 includes a first polarization beam splitter 301 , a mode conversion element 302 , a beam splitter 305 , a coupler 307 and a first quarter wave plate 308 .

[0061] The Gaussian beam output by the second arm 2 is connected to the first polarization beam splitter 301, and an output beam of the first polarization beam splitter 301 is connected to the mode converter 302, and then converted into an LG 01 Another output beam of the first polarization beam splitter 301 is connected to the beam splitter 305, and the transmitted beam of the beam splitter 305 is connected to the input end of the first arm 1; the reflected light output by the beam splitter 305 is LG 00 Gaussian beam and LG 01 The polarization directions of the modes of the Gaussian beams are orthogonal.

[0062] The LG output of the mode conversion element 302 01 The LG output from the beam splitter 305 00 The mode Gaussian beams are connected to the coupler 307 respectively, so as to be coherently superimposed through the coupler 307, and the polarization direction is adjusted by the 1 / 4 wave plate 308 to form a skyrmion mode.

[0063] In this example, the output Gaussian beam is split into two LG beams (Laguerre-Gaussian beams) by the first polarization beam splitter 301. One beam is converted from LG to Laguerre-Gaussian beams by the mode conversion element 302. 00 Mode Gaussian beam conversion to LG 01 The other beam is a Gaussian beam. 00The Gaussian light is then transmitted through the beam splitter 305 to output an LG 00 Then LG 01 Gaussian beams and LG 00 After the Gaussian light beams are adjusted to mutually orthogonal polarizations, they are coherently superimposed (linear polarization superposition) in the coupler 307, and then the polarization directions are adjusted by the 1 / 4 wave plate 308 to form optical skyrmions.

[0064] Its beam expression is: φ= R+exp(iθ) L；

[0065] Where: is the fundamental mode of Gaussian beam; is the topological charge number Vortex Gaussian beam mode; R and L represent right-handed circular polarization state and left-handed circular polarization state, respectively.

[0066] Therefore, by regulating the above-mentioned superimposed light beams, that is, adjusting the light beams to be circularly polarized through the 1 / 4 wave plate 308, the types of different skyrmions are determined by the angle of the 1 / 4 wave plate 308, so that Stokes vector optical skyrmions with different topological structures and skyrmion numbers can be generated.

[0067] The present application is based on a cavity Mamyshev oscillator, the output power of which has been amplified to the kilowatt level, and the pulse width ranges from nanoseconds to femtoseconds, which can generate high-quality Gaussian beams with excellent polarization mode and purity. Thus, ultrafast, high-beam-quality optical skyrmions can be generated to meet the needs of practical applications.

[0068] In this case, the Mamyshev oscillator outputs pulse energy far exceeding that of traditional mode-locked fiber lasers. Its unique mode-locking mechanism has great development potential in the research of structured light field regulation. Since the laser can be transmitted with extremely low loss in the optical fiber structure, the Mamyshev oscillator can break through the limitations of traditional mode-locked fiber laser output pulse energy and peak power. It is a relatively excellent choice for obtaining ultrafast pulses with higher energy, higher peak power and even fewer cycles. It is easy to obtain ultrafast structured light with high environmental stability and high beam quality, which can better meet the needs of future practical applications.

[0069] The output energy of the Mamyshev mode-locked skyrmion laser of this application is expected to be two orders of magnitude higher than that of the traditional mode-locked fiber laser, and has great potential in practical applications. In addition, the system structure of this application is flexible, has great power scaling potential, can be easily adapted to other medium gain fibers, and does not require professional or expensive optical components, providing a new solution for studying the generation of complex intracavity structure light fields.

[0070] In some embodiments, see Figure 1 and Figure 2 , Mamyshev mode-locked skyrmion fiber lasers also include:

[0071] The first 1 / 2 wave plate 303;

[0072] The first 1 / 2 wave plate 303 is disposed between the mode converter 302 and the coupler 307. The LG outputted by the mode converter 302 after conversion 01 The mode Gaussian beam is converted into a polarization direction by the first 1 / 2 wave plate 303. The first 1 / 2 wave plate 303 is arranged to facilitate the adjustment of the LG output after the mode conversion element 302 converts the polarization direction. 01 The polarization direction of the Gaussian beam provides a favorable basis for the accuracy and quality of the subsequent beam interference mode superposition, and is also conducive to enriching the polarization morphology of the beam.

[0073] In some embodiments, see Figure 1 and Figure 2 , Mamyshev mode-locked skyrmion fiber laser, and also includes:

[0074] A second 1 / 2 wave plate 304, which is disposed between the first polarization beam splitter 301 and the beam splitter 305;

[0075] An output light beam of the first polarization beam splitter 301 enters the beam splitter 305 after its polarization direction is adjusted by the second half wave plate 304 .

[0076] In this example, the setting of the second 1 / 2 wave plate 304 can adjust the polarization direction of the other output light beam of the first polarization beam splitter 301 before it enters the beam splitter 305, providing a favorable basis and possibility for the accuracy and quality of the subsequent light beam interference mode superposition, and is also conducive to enriching the polarization morphology of the light beam.

[0077] In some embodiments, see Figure 1 and Figure 2 , Mamyshev mode-locked skyrmion fiber lasers also include:

[0078] Reflector 306, reflector 306 is arranged on the optical path between beam splitter 305 and coupler 307, and the reflected light output by beam splitter 305 is transmitted to coupler 307 via reflector 306, that is, by setting reflector 306, the direction of the optical path is adjusted, which is beneficial to optimize the optical path configuration of the laser, thereby improving the accuracy and efficiency of laser transmission.

[0079] In some embodiments, see Figure 1 and Figure 2 The mode conversion element 302 is an S-Plate geometric phase retarder (S wave plate). The S-Plate is a grating with a self-organized nanostructure manufactured in high-purity fused quartz glass using a femtosecond laser. Its unique structure has a spatially varying optical axis, which can facilitate the manipulation of the polarization state of the incident light beam, thereby generating various polarization distribution states.

[0080] In addition, S-Plate can achieve millimeter-level thickness, which reduces the complexity of the laser system. Compared with other mode conversion devices, its output beam purity is high, the beam quality is good, and it supports stable operation in high-power laser systems.

[0081] In some embodiments, see Figure 1 and Figure 2 , the first arm 1 includes a first pump signal combiner 102, a first gain fiber 103, a first fiber collimator 104 with a pigtail, a second 1 / 4 wave plate 105, a third 1 / 2 wave plate 106, a second polarization beam splitter 107, a first polarization-dependent isolator 108, a fourth 1 / 2 wave plate 109 and a first blazed grating 110 connected in sequence; and

[0082] A first pump source 101 and a second fiber collimator 111;

[0083] The first pump source 101 and the second fiber collimator 111 are respectively connected to the input end of the first pump signal combiner 102 , and the output end of the first blazed grating 110 is connected to the input end of the second arm 2 .

[0084] In the first arm 1 of this example, the first pump source 101 generates pump light and injects it into the first gain fiber 103. The spectrum of the laser pulse is broadened after passing through the gain fiber, and the light beam is output through the first fiber collimator 104, and then connected to the second 1 / 4 wave plate 105, the third 1 / 2 wave plate 106 and the second polarization beam splitter 107 in sequence.

[0085] In some embodiments, see Figure 1 and Figure 2 The second arm 2 includes a second pump signal combiner 202, a second gain fiber 203, and a third fiber collimator 204 with a pigtail, which are connected in sequence;

[0086] A second polarization dependent isolator 208, a fifth 1 / 2 wave plate 209 and a second blazed grating 210 connected in sequence; and

[0087] A second pump source 201 and a fourth fiber collimator 212;

[0088] Among them, the second pump source 201 and the fourth fiber collimator 212 are respectively connected to the input end of the second pump signal combiner 202, the output end of the first blazed grating 110 is connected to the input end of the fourth fiber collimator 212, the output light beam of the third fiber collimator 204 is connected to the first polarization beam splitter 301, the transmitted light beam output by the beam splitter 305 is connected to the second polarization-dependent isolator 208, and the output end of the second blazed grating 210 is connected to the input end of the second fiber collimator 111.

[0089] In this example, the second arm 2 is used as a power amplifier as the main output end, that is, outputting a high-quality Gaussian beam to the first polarization beam splitter 301 through the third fiber collimator 204 to provide favorable conditions for the subsequent generation of optical skyrmion modes.

[0090] In some embodiments, see Figure 1 and Figure 2 The output beam of the third optical fiber collimator 204 is LG 00 Mode Gaussian beam, LG 00 After entering the first polarization beam splitter 301 , the Gaussian light beam is split into two beams of horizontal polarization and vertical polarization.

[0091] The vertically polarized light beam enters the mode conversion element 302 for mode conversion, and then is converted into horizontal polarization by the first 1 / 2 wave plate 303 to form a horizontally polarized LG 01 The horizontally polarized beam is adjusted to a vertically polarized LG beam by the second 1 / 2 wave plate 304 and then enters the beam splitter 305. The reflected beam output by the beam splitter 305 is a vertically polarized LG beam. 00 The Gaussian light beam is transmitted to the coupler 307 by the reflector 306, thereby forming a pair of light beams with orthogonal polarizations and different modes, which are coherently superimposed and the polarization direction is adjusted by the 1 / 4 wave plate 308, thereby generating Stokes vector optical skyrmion modes in different directions.

[0092] In some embodiments, see Figure 1 and Figure 2The first blazed grating 110 and the fourth fiber collimator 212, the second blazed grating 210 and the second fiber collimator 111 are respectively combined into Gaussian spectral filters with a bandwidth of 4 nm. The laser pulse is shaped (spectral filtered) after passing through the two Gaussian spectral filters, so that the high-energy pulse can be retained in the cavity, ensuring that the output Gaussian beam maintains high quality.

[0093] The first polarization-dependent isolator 108 and the second polarization-dependent isolator 208 maintain unidirectional operation of the laser, and the fourth 1 / 2 wave plate 109 and / or the fifth 1 / 2 wave plate 209 can be rotated to maximize the diffraction efficiency of the first blazed grating 110 and the second blazed grating 210 .

[0094] In some embodiments, see Figure 1 and Figure 2 , a third 1 / 4 wave plate 211, the third 1 / 4 wave plate 211 is arranged between the second blazed grating 210 and the first pump signal combiner 102; wherein, the output light beam of the second blazed grating 210 enters the input end of the first pump signal combiner 102 after the polarization direction is adjusted by the third 1 / 4 wave plate 211.

[0095] In some embodiments, due to nonlinear effects such as self-phase modulation, the laser pulse is broadened after passing through the first arm 1 and the second arm 2 of the present application, and then enters the second arm 2 again after being filtered by a Gaussian spectrum filter in the aforementioned embodiment to be broadened and amplified and then pass through another Gaussian spectrum filter. The start-up of the entire cavity mode locking is based on the NPE artificial saturable absorber composed of the second 1 / 4 wave plate 105, the third 1 / 2 wave plate 106, the second polarization beam splitter 107 and the third 1 / 4 wave plate 211, thereby achieving self-starting.

[0096] It should be noted that the transfer function of the Mamyshev oscillator is similar to a step function. The low-energy signal causes the noise signal required in the initial stage of mode locking to be unable to operate in the cavity, and self-starting cannot be achieved. The start of mode locking is achieved by rotating the NPE wave plate on the basis of continuous light operation when the center wavelength of the filter is the same. Once the mode locking is started, the separation spacing of the Gaussian spectrum filter is gradually increased to a suitable position until the cavity maintains a stable single-pulse state. Based on this, the cavity is dominated by the Mamyshev oscillator mode locking mechanism, so that the laser pulse can operate in the cavity based on self-similar evolution, and self-starting can be achieved.

[0097] The entire cavity of the present application adopts optical fiber working in the fully positive dispersion region, so that the pulse in the cavity can be broadened into a parabolic pulse based on self-similar evolution. Based on self-similar evolution, the cavity can withstand μJ or mJ level pulses, which is an output performance that cannot be achieved by other mode-locking mechanisms except the Mamyshev oscillator.

[0098] In some implementations, the first pump source 101 and the second pump source 201 are both 976 nm multi-mode high-power pump sources.

[0099] In some embodiments, both the first gain fiber 103 and the second gain fiber 203 are double-clad ytterbium-doped fibers.

[0100] The above are only some embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. Mamyshev mode-locked skyrmion fiber laser, characterized in that: include: A ring cavity Mamyshev oscillator, wherein the ring cavity Mamyshev oscillator comprises a first arm and a second arm connected in a ring shape; and A skyrmion generation module, the skyrmion generation module comprising a first polarization beam splitter, a mode conversion element, a beam splitter, a coupler and a first quarter wave plate; The Gaussian beam output by the second arm is connected to the first polarization beam splitter, and an output beam of the first polarization beam splitter is connected to the mode conversion element, and then converted into a linear polarization state LG by the mode conversion element. 01 Modulus Gaussian beam; Another output beam of the first polarization beam splitter is connected to the beam splitter, and the transmitted beam of the beam splitter is connected to the input end of the first arm; the reflected light output by the beam splitter is in the linear polarization state LG 00 mode Gaussian beam and the LG 01 The modes of the Gaussian beams have orthogonal polarization directions; The mode conversion element outputs the LG 01 mode Gaussian beam with the LG output of the beam splitter 00 The modulus Gaussian beams are connected to the couplers respectively, so as to be coherently superimposed through the couplers, and the optical skyrmions are formed after the polarization directions are adjusted by the 1 / 4 wave plate.

2. The Mamyshev mode-locked skyrmion fiber laser according to claim 1, characterized in that: Also includes: First 1 / 2 wave plate; The first 1 / 2 wave plate is arranged between the mode conversion element and the coupler, and the LG output by the mode conversion element after conversion 01 The Gaussian beam has its polarization direction converted by the first 1 / 2 wave plate.

3. The Mamyshev mode-locked skyrmion fiber laser according to claim 2, characterized in that: Also includes: A second 1 / 2 wave plate, the second 1 / 2 wave plate is arranged between the first polarization beam splitter and the beam splitter; Wherein, an output light beam of the first polarization beam splitter enters the beam splitter after the polarization direction is adjusted by the second 1 / 2 wave plate.

4. The Mamyshev mode-locked skyrmion fiber laser according to claim 1, characterized in that: Also includes: A reflector is disposed on the optical path between the beam splitter and the coupler, and the reflected light output by the beam splitter is transmitted to the coupler after the direction is adjusted by the reflector.

5. The Mamyshev mode-locked skyrmion fiber laser according to claim 1, characterized in that: The mode conversion element is an S-Plate geometric phase retarder.

6. The Mamyshev mode-locked skyrmion fiber laser according to claim 3, characterized in that: The first arm includes a first pump signal combiner, a first gain fiber, a first fiber collimator with a pigtail, a second 1 / 4 wave plate, a third 1 / 2 wave plate, a second polarization beam splitter, a first polarization-dependent isolator, a fourth 1 / 2 wave plate and a first blazed grating, which are connected in sequence; and The first pump source and the second fiber collimator, The first pump source and the second fiber collimator are respectively connected to the input end of the first pump signal combiner, and the output end of the first blazed grating is connected to the input end of the second arm.

7. The Mamyshev mode-locked skyrmion fiber laser according to claim 6, characterized in that: The second arm includes a second pump signal combiner, a second gain fiber, and a third fiber collimator with a pigtail, which are connected in sequence; A second polarization-dependent isolator, a fifth 1 / 2 wave plate and a second blazed grating connected in sequence; and a second pump source and a fourth fiber collimator; The second pump source and the fourth fiber collimator are respectively connected to the input end of the second pump signal combiner, the output end of the first blazed grating is connected to the input end of the fourth fiber collimator, the output beam of the third fiber collimator is connected to the first polarization beam splitter, the transmitted beam output by the beam splitter is connected to the second polarization-dependent isolator, and the output end of the second blazed grating is connected to the input end of the second fiber collimator.

8. The Mamyshev mode-locked skyrmion fiber laser according to claim 7, characterized in that: Also includes: a third 1 / 4 wave plate, wherein the third 1 / 4 wave plate is disposed between the second blazed grating and the first pump signal combiner; The second blazed grating output light beam enters the input end of the first pump signal combiner after the polarization direction is adjusted by the third 1 / 4 wave plate.

9. The Mamyshev mode-locked skyrmion fiber laser according to claim 7, characterized in that: The first pump source and the second pump source are both 976nm multi-mode high-power pump sources.

10. The Mamyshev mode-locked skyrmion fiber laser according to claim 6, characterized in that: The first gain optical fiber and the second gain optical fiber are double-clad ytterbium-doped optical fibers.

Images