All-fiber multi-wavelength mode-locked laser and pulse generation method

Abstract

The invention relates to the technical field of optical fiber lasers, in particular to an all-optical-fiber multi-wavelength mode-locked laser and a pulse generation method, and can solve the problem that an all-optical-fiber one-to-four-wavelength mode-locked laser based on a two-dimensional material Sb2Se3 saturable absorber has not been seen up to now to a certain extent. The device comprises a first assembly and a second assembly, the first assembly is composed of a continuous light source, a wavelength division multiplexer, an erbium-doped fiber, a multimode fiber polarization controller, an isolator, a Sb2Se3 saturable absorber based on a multimode tapering fiber, a single-mode fiber and a first optical coupler, and the first assembly is used for generating and adjusting first to fourth wavelength pulses of the first assembly; the second assembly comprises a second optical coupler, a third optical coupler, a spectrograph, a frequency spectrograph and an autocorrelator and is used for observing the pulse condition in the first assembly. The Sb2Se3 saturable absorber provided by the invention is manufactured by tapering a multimode optical fiber; the first to fourth wavelength pulse output of the first assembly can be adjusted by adjusting the polarization controller and the continuous light source input power of the first assembly.

Description

Technical Field

[0001] The present application relates to the technical field of optical fiber lasers, and in particular to an all-fiber multi-wavelength mode-locked laser and a pulse generation method. Background Art

[0002] In recent years, in order to further improve the communication capacity, modern optical fiber WDM communication systems are developing towards an increasing number of channels, so multi-wavelength mode-locked lasers with stable performance are more favored.

[0003] In addition, the high-performance multi-wavelength mode-locked light source also has great application value in the fields of laser ranging, spectral analysis and distributed optical fiber sensing. At the same time, the saturable absorber based on the two-dimensional material Sb2Se3 has advantages that other mode-locking methods do not have, such as miniaturization of mode-locked devices and simple preparation.

[0004] However, all-fiber one- to four-wavelength mode-locked lasers based on the two-dimensional material Sb2Se3 saturable absorber have not been seen so far. Summary of the invention

[0005] In order to solve the problem that all-fiber one- to four-wavelength mode-locked lasers based on the two-dimensional material Sb2Se3 saturable absorber have not been seen so far, the present application provides an all-fiber multi-wavelength mode-locked laser and a pulse generation method.

[0006] The embodiment of the present application is implemented as follows:

[0007] In a first aspect, the present application provides an all-fiber multi-wavelength mode-locked laser, comprising a first component and a second component;

[0008] The first component includes a continuous light source, a wavelength division multiplexer, an erbium-doped optical fiber, a Sb2Se3 saturable absorber of a tapered multimode optical fiber, an isolator, a multimode optical fiber polarization controller, a 300-meter single-mode optical fiber, and a first optical coupler;

[0009] One input end of the wavelength division multiplexer is connected to a continuous light source, and the output end is connected to an erbium-doped optical fiber; the erbium-doped optical fiber, the Sb2Se3 saturable absorber of the tapered multimode optical fiber, the isolator, the multimode optical fiber polarization controller, the 300-meter single-mode optical fiber, and the first optical coupler are connected in sequence, and one output end of the first optical coupler is connected to another input end of the wavelength division multiplexer to form a ring cavity;

[0010] The second component includes a second optical coupler, a third optical coupler, a spectrometer, a spectrum analyzer and an autocorrelator;

[0011] The input end of the second optical coupler is connected to an output end of the first optical coupler, an output end of the second optical coupler is connected to an input end of a third optical coupler, another output end of the second optical coupler is connected to a spectrometer, and an output end of the third optical coupler is connected to a spectrometer and an autocorrelator;

[0012] The Sb2Se3 saturable absorber of the tapered multimode optical fiber is used as a pulse mode-locking device in the laser cavity;

[0013] The first component is used to generate one to four wavelength mode-locked pulse outputs in the 1550nm band;

[0014] The second component is used to observe and evaluate the pulse conditions generated in the first component.

[0015] In a possible implementation, the wavelength division multiplexer is a 1550 / 980nm wavelength division multiplexer;

[0016] The continuous light source is a 980nm continuous light source;

[0017] The isolator is a 1550nm isolator;

[0018] The multimode optical fiber in the Sb2Se3 saturable absorber of the tapered multimode optical fiber is a G651 multimode optical fiber;

[0019] The first optical coupler is a 30 / 70 optical coupler;

[0020] The 980nm input end of the wavelength division multiplexer is connected to the continuous light source, and the 1550nm input end is connected to the 70% output end of the first optical coupler.

[0021] In a possible implementation, the Sb2Se3 saturable absorber of the tapered multimode optical fiber is produced by depositing Sb2Se3 on the waist of the tapered multimode optical fiber after tapering the G651 multimode optical fiber to 22 μm using an optically induced deposition method.

[0022] In a possible implementation, the optical induced deposition method includes:

[0023] Mix Sb2Se3 powder with 20mL of alcohol solution;

[0024] After ultrasonic vibration for 1.5 hours, the mixture was allowed to stand for 60 minutes;

[0025] Take the upper layer of Sb2Se3 solution and drop it onto the surface of multimode tapered optical fiber;

[0026] Inject 980nm continuous wave laser into the optical fiber and let it stand for 1 hour;

[0027] Wait for Sb2Se3 to dry and precipitate to obtain a Sb2Se3 mode-locked device.

[0028] In a possible implementation, the multimode fiber polarization controller is formed by cutting a suitable length of G651 multimode fiber, placing it into a three-ring polarization controller in a winding order of 2 / 3 / 2, and leaving suitable fiber lengths at both ends for fusion splicing.

[0029] In a possible implementation, all components in the first assembly are fused by aligning the fiber cores.

[0030] In a possible implementation, the second optical coupler and the third optical coupler are both 50 / 50 optical couplers;

[0031] An input end of the second optical coupler is connected to 30% of the output end of the first optical coupler, and another output end is connected to the input end of the third optical coupler;

[0032] The spectrometer, spectrum analyzer and autocorrelator are sequentially connected to the remaining three ports of the second optical coupler and the third optical coupler.

[0033] In a possible implementation, the Sb2Se3 saturable absorber of the tapered multimode optical fiber can generate single-, dual-, and quad-wavelength soliton pulses and three-wavelength multi-longitudinal mode Q-switched pulses:

[0034] The single-wavelength soliton pulse has an output wavelength of 1558nm or 1565nm, a pulse width of 2.61 or 3.02ps, and a signal-to-noise ratio of 51.72dB;

[0035] The dual-wavelength soliton pulse has output wavelengths of 1559nm and 1565nm, a wavelength interval of 6nm, a pulse width of 3.43ps, and a signal-to-noise ratio of 47.05dB;

[0036] The three-wavelength multi-longitudinal mode Q-switched pulse has output wavelengths of 1534nm, 1539nm and 1562nm, and the highest signal-to-noise ratio is 45.49dB;

[0037] The four-wavelength soliton pulse has output wavelengths of 1540nm, 1560nm, 1562nm and 1565nm, and a signal-to-noise ratio of 52.95dB.

[0038] In a possible implementation, the repetition frequencies of the single-wavelength soliton pulse, the dual-wavelength soliton pulse, the three-wavelength multi-longitudinal mode Q-switched pulse and the four-wavelength soliton pulse are all 686.7 kHz.

[0039] In a second aspect, the present application provides a pulse generating method, comprising:

[0040] Generate pulses through the first component, connect 30% of the output end of the first optical coupler to the second optical coupler with a 50% split ratio, and connect 50% of the output end of the second optical coupler to the 50 / 50 third optical coupler;

[0041] Observe and identify pulse types through spectrometer, spectrum analyzer and autocorrelator;

[0042] The wavelength is switched by adjusting the continuous light source or polarization controller.

[0043] The technical solution provided by this application can at least achieve the following beneficial effects:

[0044] The all-fiber multi-wavelength mode-locked laser and pulse generation method provided by the present application adjust the pump power or polarization controller in the first component to switch the one to four wavelength pulses of the first component; by using the Sb2Se3 saturable absorber of the tapered multimode fiber and the multimode fiber polarization controller, the center wavelength of the traditional soliton pulse single-wavelength soliton pulse is 1558nm or 1565nm, the pulse width is 2.61 or 3.02ps, and the signal-to-noise ratio is 51.72dB; the dual-wavelength soliton pulse has a center wavelength of 1559nm and 1565nm, a wavelength interval of 6nm, a pulse width of 3.43ps, and a signal-to-noise ratio of 51.72dB. The signal-to-noise ratio is 47.05dB; the three-wavelength multi-longitudinal mode Q-switched pulse has output wavelengths of 1534nm, 1539nm and 1562nm, among which the highest signal-to-noise ratio is 45.49dB; the four-wavelength soliton pulse has output wavelengths of 1540nm, 1560nm, 1562nm and 1565nm, and the signal-to-noise ratio is 52.95dB; the repetition frequency of the above pulses is 686.7kHz, and the signal-to-noise ratio exceeds 30dB, which illustrates the tunability and stability of the wavelength; the pulses have their own central wavelength, pulse width and mode-locking type, which can meet the needs of different wavelength pulses in different occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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 labor.

[0046] Figure 1 is a schematic structural diagram of an all-fiber multi-wavelength mode-locked laser shown in an exemplary embodiment of the present application;

[0047] Figure 2 is a pulse schematic diagram shown in an exemplary embodiment of the present application;

[0048] Figure 3It is a flowchart of a pulse generating method shown in an exemplary embodiment of the present application.

[0049] Reference numerals:

[0050] 1. Continuous light source; 2. Wavelength division multiplexer; 3. Erbium-doped optical fiber; 4. Sb2Se3 saturable absorber of tapered multimode optical fiber; 5. Isolator; 6. Multimode optical fiber polarization controller; 7. 300 meters of single-mode optical fiber; 8. First optical coupler; 9. Second optical coupler; 10. Third optical coupler; 11. Spectrometer; 12. Spectrum analyzer; 13. Autocorrelator. DETAILED DESCRIPTION

[0051] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, not all of the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0052] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and common meanings.

[0053] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0054] The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0055] Before explaining the all-fiber multi-wavelength mode-locked laser provided in the embodiment of the present application, the application scenario and implementation environment of the embodiment of the present application are first introduced.

[0056] In recent years, in order to further improve the communication capacity, modern optical fiber WDM communication systems are developing towards an increasing number of channels, so multi-wavelength mode-locked lasers with stable performance are more favored.

[0057] In addition, multi-wavelength mode-locked light sources with excellent performance also have great application value in the fields of laser ranging, spectral analysis and distributed optical fiber sensing. At the same time, saturable absorbers based on two-dimensional materials have advantages that other mode-locking methods do not have, such as miniaturization of mode-locked devices and simple preparation.

[0058] However, all-fiber one- to four-wavelength mode-locked lasers based on two-dimensional material saturable absorbers have not been seen so far.

[0059] Based on this, the present application provides an all-fiber multi-wavelength mode-locked laser and a pulse generation method. By observing the second component and adjusting the polarization controller and continuous light source input power of the first component, the one to four wavelength pulse output of the first component can be adjusted.

[0060] Next, the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems will be described in detail through embodiments and in combination with the accompanying drawings. The embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of them.

[0061] Figure 1 It is a schematic structural diagram of an all-fiber multi-wavelength mode-locked laser shown in an exemplary embodiment of the present application.

[0062] In an exemplary embodiment, Figure 1 As shown, an all-fiber multi-wavelength mode-locked laser is provided. In this embodiment, the device includes a first component and a second component;

[0063] The first component includes a continuous light source, a wavelength division multiplexer, an erbium-doped optical fiber, a Sb2Se3 saturable absorber of a tapered multimode optical fiber, an isolator, a multimode optical fiber polarization controller, a 300-meter single-mode optical fiber, and a first optical coupler;

[0064] One input end of the wavelength division multiplexer is connected to a continuous light source, and the output end is connected to an erbium-doped optical fiber; the erbium-doped optical fiber, the Sb2Se3 saturable absorber of the tapered multimode optical fiber, the isolator, the multimode optical fiber polarization controller, the 300-meter single-mode optical fiber, and the first optical coupler are connected in sequence, and one output end of the first optical coupler is connected to another input end of the wavelength division multiplexer to form a ring cavity;

[0065] The second component includes a second optical coupler, a third optical coupler, a spectrometer, a spectrum analyzer and an autocorrelator;

[0066] The input end of the second optical coupler is connected to an output end of the first optical coupler, an output end of the second optical coupler is connected to an input end of a third optical coupler, another output end of the second optical coupler is connected to a spectrometer, and an output end of the third optical coupler is connected to a spectrometer and an autocorrelator;

[0067] The Sb2Se3 saturable absorber of the tapered multimode optical fiber is used as a pulse mode-locking device in the laser cavity;

[0068] The first component is used to generate one to four wavelength mode-locked pulse outputs in the 1550nm band;

[0069] The second component is used to observe and evaluate the pulse conditions generated in the first component.

[0070] In a possible implementation manner, the specific implementation structure also includes:

[0071] The wavelength division multiplexer is a 1550 / 980nm wavelength division multiplexer;

[0072] The continuous light source is a 980nm continuous light source;

[0073] The isolator is a 1550nm isolator;

[0074] The multimode optical fiber in the Sb2Se3 saturable absorber of the tapered multimode optical fiber is a G651 multimode optical fiber;

[0075] The first optical coupler is a 30 / 70 optical coupler;

[0076] The 980nm input end of the wavelength division multiplexer is connected to the continuous light source, and the 1550nm input end is connected to the 70% output end of the first optical coupler.

[0077] The Sb2Se3 saturable absorber of the tapered multimode optical fiber is produced by depositing Sb2Se3 on the waist of the tapered multimode optical fiber by optically induced deposition after tapering the G651 multimode optical fiber to 22 μm.

[0078] The optical induced deposition method comprises:

[0079] Mix Sb2Se3 powder with 20mL of alcohol solution;

[0080] After ultrasonic vibration for 1.5 hours, the mixture was allowed to stand for 60 minutes;

[0081] Take the upper layer of Sb2Se3 solution and drop it onto the surface of multimode tapered optical fiber;

[0082] Inject 980nm continuous wave laser into the optical fiber and let it stand for 1 hour;

[0083] Wait for Sb2Se3 to dry and precipitate to obtain a Sb2Se3 mode-locked device.

[0084] Specifically, the multimode optical fiber polarization controller is formed by cutting a G651 multimode optical fiber of appropriate length, placing it into a three-ring polarization controller in a winding order of 2 / 3 / 2, and leaving appropriate optical fiber lengths at both ends for fusion splicing.

[0085] In a possible implementation, all components in the first assembly are fused by aligning the fiber cores.

[0086] In a possible implementation, the second optical coupler and the third optical coupler are both 50 / 50 optical couplers;

[0087] An input end of the second optical coupler is connected to 30% of the output end of the first optical coupler, and another output end is connected to the input end of the third optical coupler;

[0088] The spectrometer, spectrum analyzer and autocorrelator are sequentially connected to the remaining three ports of the second optical coupler and the third optical coupler.

[0089] Figure 2 It is a pulse schematic diagram shown in an exemplary embodiment of the present application.

[0090] In one possible implementation, Figure 2 As shown, the Sb2Se3 saturable absorber of the tapered multimode optical fiber can generate single-, dual-, and quad-wavelength soliton pulses and three-wavelength multi-longitudinal mode Q-switched pulses:

[0091] The single-wavelength soliton pulse has an output wavelength of 1558nm or 1565nm, a pulse width of 2.61 or 3.02ps, and a signal-to-noise ratio of 51.72dB;

[0092] The dual-wavelength soliton pulse has output wavelengths of 1559nm and 1565nm, a wavelength interval of 6nm, a pulse width of 3.43ps, and a signal-to-noise ratio of 47.05dB;

[0093] The three-wavelength multi-longitudinal mode Q-switched pulse has output wavelengths of 1534nm, 1539nm and 1562nm, and the highest signal-to-noise ratio is 45.49dB;

[0094] The four-wavelength soliton pulse has output wavelengths of 1540nm, 1560nm, 1562nm and 1565nm, and a signal-to-noise ratio of 52.95dB.

[0095] The repetition frequencies of the single-wavelength soliton pulse, the dual-wavelength soliton pulse, the three-wavelength multi-longitudinal mode Q-switched pulse and the four-wavelength soliton pulse are all 686.7 kHz.

[0096] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the instructions, these steps are not necessarily executed in sequence according to the order of the instructions. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the above-mentioned embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the steps or stages in other steps.

[0097] Figure 3 It is a flowchart of a pulse generating method shown in an exemplary embodiment of the present application.

[0098] In an exemplary embodiment, Figure 3 As shown, the pulse generating method comprises the following steps:

[0099] Step 100: A pulse is generated by a first component, and 30% of the output ends of the first optical coupler in the first component are connected to a second optical coupler with a splitting ratio of 50%;

[0100] Step 200: The 50% output terminal of the second optical coupler is connected to a 50 / 50 third optical coupler;

[0101] Step 300: a spectrometer, a spectrum analyzer and an autocorrelator are connected to the output ends of the second optical coupler and the third optical coupler respectively;

[0102] Step 400: Observe and identify the pulse type through a spectrometer, a spectrum analyzer and an autocorrelator;

[0103] Step 500: Switch the wavelength by adjusting the continuous light source or polarization controller of the first component.

[0104] It can be seen that some embodiments of the present application use the Sb2Se3 saturable absorber of the tapered multimode fiber and the multimode fiber polarization controller, and simultaneously adjust the pump power or the polarization controller in the first component to switch the first component to one to four wavelength pulses; the central wavelength of the single-wavelength soliton pulse is 1558nm or 1565nm, the pulse width is 2.61 or 3.02ps, and the signal-to-noise ratio is 51.72dB; the dual-wavelength soliton pulse has a central wavelength of 1559nm and 1565nm, a wavelength interval of 6nm, a pulse width of 3.43ps, and a signal-to-noise ratio of 47.0 5dB; three-wavelength multi-longitudinal mode Q-switched pulses, with output wavelengths of 1534nm, 1539nm and 1562nm, among which the highest signal-to-noise ratio is 45.49dB; four-wavelength soliton pulses, with output wavelengths of 1540nm, 1560nm, 1562nm and 1565nm, with a signal-to-noise ratio of 52.95dB; the repetition frequency of the above pulses is 686.7kHz, and the signal-to-noise ratio exceeds 30dB, which illustrates the tunability and stability of the wavelength; the pulses have their own central wavelength, pulse width and mode-locking type, which can meet the needs of different wavelength pulses in different occasions.

[0105] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. An all-fiber multi-wavelength mode-locked laser, characterized in that: comprising a first component and a second component; The first component includes a continuous light source, a wavelength division multiplexer, an erbium-doped optical fiber, a Sb2Se3 saturable absorber of a tapered multimode optical fiber, an isolator, a multimode optical fiber polarization controller, a 300-meter single-mode optical fiber, and a first optical coupler; One input end of the wavelength division multiplexer is connected to a continuous light source, and the output end is connected to an erbium-doped optical fiber; the erbium-doped optical fiber, the Sb2Se3 saturable absorber of the tapered multimode optical fiber, the isolator, the multimode optical fiber polarization controller, the 300-meter single-mode optical fiber, and the first optical coupler are connected in sequence, and one output end of the first optical coupler is connected to another input end of the wavelength division multiplexer to form a ring cavity; The second component includes a second optical coupler, a third optical coupler, a spectrometer, a spectrum analyzer and an autocorrelator; The input end of the second optical coupler is connected to an output end of the first optical coupler, an output end of the second optical coupler is connected to an input end of a third optical coupler, another output end of the second optical coupler is connected to a spectrometer, and an output end of the third optical coupler is connected to a spectrometer and an autocorrelator; The Sb2Se3 saturable absorber of the tapered multimode optical fiber is used as a pulse mode-locking device in the laser cavity; The first component is used to generate one to four wavelength mode-locked pulse outputs in the 1550nm band; The second component is used to observe and evaluate the pulse conditions generated in the first component.

2. The all-fiber multi-wavelength mode-locked laser according to claim 1, characterized in that: The wavelength division multiplexer is a 1550 / 980nm wavelength division multiplexer; The continuous light source is a 980nm continuous light source; The isolator is a 1550nm isolator; The multimode optical fiber in the Sb2Se3 saturable absorber of the tapered multimode optical fiber is a G651 multimode optical fiber; The first optical coupler is a 30 / 70 optical coupler; The 980nm input end of the wavelength division multiplexer is connected to the continuous light source, and the 1550nm input end is connected to the 70% output end of the first optical coupler.

3. The all-fiber multi-wavelength mode-locked laser according to claim 1, characterized in that: The Sb2Se3 saturable absorber of the tapered multimode optical fiber is produced by depositing Sb2Se3 on the waist of the tapered multimode optical fiber by optically induced deposition after the G651 multimode optical fiber is tapered to 22 μm.

4. The all-fiber multi-wavelength mode-locked laser according to claim 3, characterized in that: The optical induced deposition method comprises: Mix Sb2Se3 powder with 20mL of alcohol solution; After ultrasonic vibration for 1.5 hours, the mixture was allowed to stand for 60 minutes; Take the upper layer of Sb2Se3 solution and drop it onto the surface of multimode tapered optical fiber; Inject 980nm continuous wave laser into the optical fiber and let it stand for 1 hour; Wait for Sb2Se3 to dry and precipitate to obtain a Sb2Se3 mode-locked device.

5. The all-fiber multi-wavelength mode-locked laser according to claim 1, characterized in that: The multimode optical fiber polarization controller is formed by cutting a G651 multimode optical fiber of appropriate length, placing it into a three-ring polarization controller in a winding order of 2 / 3 / 2, and leaving appropriate optical fiber lengths at both ends for fusion splicing.

6. The all-fiber multi-wavelength mode-locked laser according to claim 5, characterized in that: The components in the first assembly are fused together by aligning the fiber cores.

7. The all-fiber multi-wavelength mode-locked laser according to claim 1, characterized in that: The second optical coupler and the third optical coupler are both 50 / 50 optical couplers; An input end of the second optical coupler is connected to 30% of the output end of the first optical coupler, and another output end is connected to the input end of the third optical coupler; The spectrometer, spectrum analyzer and autocorrelator are sequentially connected to the remaining three ports of the second optical coupler and the third optical coupler.

8. The all-fiber multi-wavelength mode-locked laser according to claim 1, characterized in that: The Sb2Se3 saturable absorber of the tapered multimode optical fiber can generate single-, dual-, and quad-wavelength soliton pulses and three-wavelength multi-longitudinal mode Q-switched pulses: The single-wavelength soliton pulse has an output wavelength of 1558nm or 1565nm, a pulse width of 2.61 or 3.02ps, and a signal-to-noise ratio of 51.72dB; The dual-wavelength soliton pulse has output wavelengths of 1559nm and 1565nm, a wavelength interval of 6nm, a pulse width of 3.43ps, and a signal-to-noise ratio of 47.05dB; The three-wavelength multi-longitudinal mode Q-switched pulse has output wavelengths of 1534nm, 1539nm and 1562nm, and the highest signal-to-noise ratio is 45.49dB; The four-wavelength soliton pulse has output wavelengths of 1540nm, 1560nm, 1562nm and 1565nm, and a signal-to-noise ratio of 52.95dB.

9. The all-fiber multi-wavelength mode-locked laser according to claim 8, characterized in that: The repetition frequencies of the single-wavelength soliton pulse, the dual-wavelength soliton pulse, the three-wavelength multi-longitudinal mode Q-switched pulse and the four-wavelength soliton pulse are all 686.7 kHz.

10. A pulse generation method, applied to the all-fiber multi-wavelength mode-locked laser according to any one of claims 1 to 9, characterized in that: include: Generate pulses through the first component, connect 30% of the output end of the first optical coupler to the second optical coupler with a 50% split ratio, and connect 50% of the output end of the second optical coupler to the 50 / 50 third optical coupler; Observe and identify pulse types through spectrometer, spectrum analyzer and autocorrelator; The wavelength is switched by adjusting the continuous light source or polarization controller.

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