Optical fiber soliton modulation system

Abstract

The invention relates to an optical fiber soliton modulation system which comprises a light source module, a modulation module and a detection module. The light source module is used for generating an initial optical soliton signal; the light source module comprises a mode-locked fiber laser, and the mode-locked fiber laser is used for generating an initial optical soliton source. The modulation module is connected with the light source module and is used for receiving and modulating the initial optical soliton signal; in the modulation process, pulse waveforms and spectrums of optical solitons in the orthogonal polarization direction are changed by changing different types of soliton parameters; and the detection module is connected with the modulation module and is used for detecting the time domain and frequency domain characteristics of the modulated optical soliton in the orthogonal polarization direction so as to realize data observation and research. Compared with the prior art, the state of the optical fiber soliton is flexibly changed by controlling extra-cavity parameters. After polarization beam splitting, the modulated orthogonal component shows unique properties in the time domain and the frequency domain. Therefore, the current modulation range of the optical fiber solitons is greatly expanded.

Description

Technical Field

[0001] The invention relates to the technical field of nonlinear optical fiber optics, and in particular to an optical fiber soliton modulation system. Background Art

[0002] Mode-locked fiber lasers achieve efficient laser output by modulating repeatedly circulating light pulses in the resonant cavity. These light pulses are affected by many factors in the cavity, including dispersion, loss, gain, nonlinearity, saturation absorption, etc. In passively mode-locked fiber lasers, since the laser operates in the normal or anomalous dispersion region, coupled with the differences in the components in the fiber resonant cavity, the parameter distribution in the cavity is different. Lasers can generate different types of optical solitons, such as traditional solitons, dissipative solitons, dark solitons, dispersion-managed solitons, etc.

[0003] In recent decades, mode-locked fiber lasers have made significant progress in generating ultrashort pulses, making them widely used in fiber-optic communications, fiber-optic sensing, medical treatment, military, scientific research and other fields. However, mode-locked fiber lasers obtain ultrashort laser pulses by modulating intracavity parameters. Limited by the adjustment range of intracavity parameters, some more complex fiber solitons (such as high-order fiber vector solitons) are difficult to obtain directly by building a fiber laser oscillator or amplifier. In order to solve this problem, the emergence of a new technology is very necessary. This technology needs to have higher flexibility and a wide modulation range, which can effectively optimize the performance of existing systems, alleviate the complexity caused by the adjustment of design parameters, and thus improve pulse quality and stability. By adopting this method, the laser can operate under a wider range of operating conditions, promoting the further development of ultrashort pulse technology. Summary of the invention

[0004] The purpose of the present invention is to provide a fiber soliton modulation system to overcome the above-mentioned defects of the prior art, and flexibly change the state of fiber solitons by controlling extracavity parameters (such as amplitude ratio, time delay, projection angle, phase difference, pulse chirp). After polarization splitting, the modulated orthogonal components show unique properties in the time domain and frequency domain. This greatly expands the current modulation range of fiber solitons.

[0005] The present invention provides a fiber soliton modulation system, comprising: a light source module, a modulation module and a detection module; the light source module is used to generate an initial optical soliton signal; the light source module comprises a mode-locked fiber laser, and the mode-locked fiber laser is used to generate an initial optical soliton source;

[0006] The modulation module is connected to the light source module and is used to receive and modulate the initial optical soliton signal; during the modulation process, the pulse waveform and spectrum of the optical soliton in the orthogonal polarization direction are changed by changing the parameters of different types of solitons;

[0007] The detection module is connected to the modulation module and is used to detect the time domain and frequency domain characteristics of the modulated optical soliton in the orthogonal polarization direction, so as to realize data observation and research. The system uses a combination of multiple optical elements to achieve precise control of the optical soliton signal and ensures the optimality of signal modulation through a real-time detection mechanism, thereby significantly improving the efficiency and quality of data transmission.

[0008] Further, the modulation module includes: an optical fiber isolator, a first optical fiber collimator, a first λ / 4 wave plate, a λ / 2 wave plate, a second λ / 4 wave plate, a second optical fiber collimator, a first optical fiber polarization beam splitter, a first three-port circulator, a first electric field amplitude modulator, a first optical fiber delay line, a second three-port circulator, a second electric field amplitude modulator, a second optical fiber delay line, a second optical fiber polarization beam splitter, a polarization controller, a third optical fiber collimator, a solid polarization beam splitter, a first detector, and a second detector, the first three-port circulator is provided with a first chirped fiber Bragg grating, and the second three-port circulator is provided with a second chirped fiber Bragg grating; or the first three-port circulator and the first chirped fiber Bragg grating, the second three-port circulator and the second chirped fiber Bragg grating are replaced by dispersion compensating optical fiber.

[0009] Specifically, the optical fiber output port of the mode-locked fiber laser is connected to the optical fiber input port of the optical fiber isolator. The optical fiber output port of the optical fiber isolator is connected to a wave plate combination composed of a λ / 4 wave plate, a λ / 2 wave plate, and a λ / 4 wave plate through a first optical fiber collimator. Then, it is connected to the optical fiber input port of the first optical fiber polarization beam splitter through a second optical fiber collimator. The first output port of the first optical fiber polarization beam splitter is connected to the first port of the first three-port circulator. The second port of the first three-port circulator is connected to the first chirped fiber Bragg grating. The third port of the first three-port circulator is connected to the input port of the first optical fiber delay line through a first electric field amplitude modulator. The output port of the first optical fiber delay line is connected to the first input port of the second optical fiber polarization beam splitter. The second output port of the first optical fiber polarization beam splitter is connected to the second port of the second three-port circulator. The second port of the second three-port circulator is connected to the second chirped fiber Bragg grating. The third port of the second three-port circulator is connected to the input port of the second optical fiber delay line through a second electric field amplitude modulator. The output port of the second optical fiber delay line is connected to the second input port of the second optical fiber polarization beam splitter. The output port of the second optical fiber polarization beam splitter is connected to the third optical fiber collimator through a polarization controller. The first output port of the solid polarization beam splitter is connected to the input port of the first detector. The second output port of the solid polarization beam splitter is connected to the input port of the second detector.

[0010] Furthermore, the mode-locked fiber laser is one of ytterbium-doped mode-locked fiber laser, erbium-doped mode-locked fiber laser, and thulium-doped mode-locked fiber laser. When the passive mode-locked fiber laser is erbium-doped mode-locked fiber laser or thulium-doped mode-locked fiber laser, the three-port circulator and chirped fiber Bragg grating in the system will be replaced by dispersion-compensating fiber, and other optical components also need to be replaced with components of corresponding bands.

[0011] Further, when the mode-locked fiber laser is an ytterbium-doped mode-locked fiber laser, the system includes: an ytterbium-doped mode-locked fiber laser, a 1064nm fiber isolator, a first 1064nm fiber collimator, a first λ / 4 wave plate, a λ / 2 wave plate, a second λ / 4 wave plate, a second 1064nm fiber collimator, a first 1064nm fiber polarization beam splitter, a first 1064nm three-port circulator, a first 1064nm electric field amplitude modulator, a first 1064nm fiber delay line, a second 1064nm three-port circulator, a second 1064nm electric field amplitude modulator, a second 1064nm fiber delay line, a second 1064nm fiber polarization beam splitter, a polarization controller, a third 1064nm fiber collimator, a 1064nm solid polarization beam splitter, a first detector, and a second detector, wherein the first 1064nm three-port circulator and the second 1064nm three-port circulator are respectively provided with chirped fiber Bragg gratings.

[0012] The chirped fiber Bragg grating provides anomalous group velocity dispersion in the 1064nm band, which can independently change the group velocity dispersion experienced by the two branch fiber laser pulses in the fiber soliton modulation system, thereby obtaining fiber solitons with different characteristics in the orthogonal polarization directions at the output end. The adjustment range of the 1064nm fiber delay line is more than 100 picoseconds, and the time delay of a single polarization component can be adjusted so that the pulse after coupling exhibits different polarization state characteristics. If the mode-locked fiber laser operates in other bands, the fiber delay line of the corresponding band needs to be replaced. The three-port circulator supports unidirectional transmission of optical signals. If the mode-locked fiber laser operates in other bands, the three-port circulator of the corresponding band needs to be replaced. The pigtails of the 1064nm fiber polarization beam splitter are HI1060 fiber and PM1060 fiber, which can decompose or couple the orthogonal polarization components of the 1064nm band pulsed laser. If the mode-locked fiber laser operates in other bands, the fiber polarization beam splitter of the corresponding band needs to be replaced.

[0013] In the fiber soliton modulation system, an ytterbium-doped mode-locked fiber laser is used to generate an optical soliton signal in the 1064nm band. The fiber isolator is used to limit the direction of light so that the optical signal can only be transmitted in a single direction. The light reflected by the fiber echo can be well isolated by the fiber isolator, which improves the efficiency of light wave transmission and effectively avoids the damage of the reflected light signal to the light source. The fiber delay line can adjust the time delay in the system so that the optical solitons of the two branches are in a time domain synchronous or asynchronous state. The role of the polarization controller is to change the linear birefringence in the system. The role of the two fiber polarization beam splitters is to decompose or couple the orthogonal polarization components of the optical signal. The various components of the fiber soliton modulation system are connected through standard single-mode optical fiber and polarization-maintaining optical fiber.

[0014] Further, when the mode-locked fiber laser is an erbium-doped mode-locked fiber laser, the system includes: an erbium-doped mode-locked fiber laser, a 1550nm fiber isolator, a first 1550nm fiber collimator, a first λ / 4 wave plate, a λ / 2 wave plate, a second λ / 4 wave plate, a second 1550nm fiber collimator, a first 1550nm fiber polarization beam splitter, a first 1550nm three-port circulator, a first 1550nm electric field amplitude modulator, a first 1550nm fiber delay line, a second 1550nm three-port circulator, a second 1550nm electric field amplitude modulator, A modulator, a second 1550nm optical fiber delay line, a second 1550nm optical fiber polarization beam splitter, a polarization controller, a third 1550nm optical fiber collimator, a 1550nm solid polarization beam splitter, a first detector, a second detector, the first 1550nm three-port circulator and the second 1550nm three-port circulator are respectively provided with a chirped fiber Bragg grating; since the system operates in an anomalous dispersion band, the first three-port circulator and the first chirped fiber Bragg grating, the second three-port circulator and the second chirped fiber Bragg grating are replaced by 1550nm dispersion compensating optical fiber.

[0015] Further, when the mode-locked fiber laser is a thulium-doped mode-locked fiber laser, the fiber soliton modulation system includes: a thulium-doped mode-locked fiber laser, a 2000nm fiber isolator, a first 2000nm fiber collimator, a first λ / 4 wave plate, a λ / 2 wave plate, a second λ / 4 wave plate, a second 2000nm fiber collimator, a first 2000nm fiber polarization beam splitter, a first 2000nm three-port circulator, a first 2000nm electric field amplitude modulator, a first 2000nm fiber delay line, The second 2000nm three-port circulator, the second 2000nm electric field amplitude modulator, the second 2000nm optical fiber delay line, the second 2000nm optical fiber polarization beam splitter, the polarization controller, the third 2000nm optical fiber collimator, the 2000nm solid polarization beam splitter, the first detector, the second detector, the first 2000nm three-port circulator and the second 2000nm three-port circulator are respectively provided with chirped fiber Bragg gratings; the chirped fiber Bragg gratings are used to compensate for the normal group velocity dispersion in the system. And the size of the chirp depends on how much the net dispersion value in the system needs to be set. Since the system works in the anomalous dispersion band, the first three-port circulator and the first chirped fiber Bragg grating, the second three-port circulator and the second chirped fiber Bragg grating are replaced by 2000nm dispersion compensation fiber.

[0016] Furthermore, the pigtail between the first optical fiber polarization beam splitter and the second optical fiber polarization beam splitter is a polarization-maintaining optical fiber, and the other pigtails in the system are all standard single-mode optical fibers.

[0017] Furthermore, the polarization controller is a three-paddle polarization controller. By rotating the three paddles, the linear birefringence in the system can be effectively changed.

[0018] Furthermore, the standard single-mode optical fiber includes: SMF-28, HI1060 or SM1950; the polarization-maintaining optical fiber (12) includes: PM1550, PM1060 or PM1950;

[0019] If the mode-locked fiber laser adopts an ytterbium-doped mode-locked fiber laser, a combination of HI1060 and PM1060 is selected; if the mode-locked fiber laser adopts an erbium-doped mode-locked fiber laser, a combination of SMF-28 and PM1550 is selected; if the mode-locked fiber laser adopts a thulium-doped mode-locked fiber laser, a combination of SM1950 and PM1950 is selected.

[0020] Furthermore, the detection module includes: a photodetector, an optical power meter and a spectrum analyzer, which are used to detect the orthogonal components of the modulated solitons.

[0021] The working principle of the present invention is as follows: First, the soliton emitted from the mode-locked fiber laser passes through the fiber isolator, passes through the fiber isolator, and then is collimated by the first fiber collimator and then injected into the combination of wave plates. The combination of λ / 4 wave plate, λ / 2 wave plate, and λ / 4 wave plate can flexibly adjust the polarization state of the optical soliton. Subsequently, after the optical signal is received by the second fiber collimator, it is split by the first fiber polarization beam splitter to separate the orthogonal components of the soliton, and the orthogonal components pass through the first three-port circulator and the second three-port circulator respectively. The first three-port circulator and the second three-port circulator are respectively provided with a first chirped fiber Bragg grating and a second chirped fiber Bragg grating, which can be used to adjust the group velocity dispersion in the system, and the orthogonal electric field of the soliton is modulated by the first fiber amplitude modulator and the first fiber time delay line and the second fiber amplitude modulator and the second fiber time delay line. Afterwards, the modulated electric field is combined with the help of the second polarization beam splitter, and the polarization state of the modulated soliton is further changed by the polarization controller. Finally, the electric field of the modulated soliton is collimated by the third fiber collimator, and the collimated laser beam is split by a solid polarization beam splitter. The first detector and the second detector respectively detect the pulse waveform and spectrum of the modulated soliton in the orthogonal polarization direction.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The present invention uses optical fiber polarization beam splitters, optical fiber delay lines and other components that match the operating band of the mode-locked fiber laser, which can effectively adjust the laser pulse and greatly expand the current adjustment range of soliton pulses.

[0024] (2) The present invention uses ytterbium-doped mode-locked fiber lasers, erbium-doped mode-locked fiber lasers, and thulium-doped mode-locked fiber lasers. Fiber polarization beam splitters, fiber delay lines, and other components that match the working band are selected to effectively obtain 1.06μm, 1.55μm, and 2μm pulsed fiber lasers. In addition, the mode-locked fiber laser can also work in other bands (such as the visible light band), but the components of the corresponding bands need to be replaced.

[0025] (3) In the present invention, the optical fiber delay line in the optical fiber soliton modulation system can change the delay of a single polarization component of a pulse. By adjusting the delay line, the polarization state of the pulse can be continuously adjusted.

[0026] (4) In the present invention, the two chirped fiber Bragg gratings in the fiber soliton modulation system can independently change the group velocity dispersion experienced by the two branch laser pulses, providing favorable conditions for observing pulses of different states at the output end.

[0027] (5) The present invention overcomes the limitations of current research on the frequency domain and time domain characteristics of solitons. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the fiber soliton modulation system.

[0029] Figure numerals: 1, mode-locked fiber laser; 2, standard single-mode optical fiber; 3, optical fiber isolator; 4-1, first optical fiber collimator; 4-2, second optical fiber collimator; 4-3, third optical fiber collimator; 5-1, first λ / 4 wave plate; 5-2, second λ / 4 wave plate; 6, λ / 2 wave plate; 7-1, first optical fiber polarization beam splitter; 7-2, second optical fiber polarization beam splitter; 8-1, first three-port circulator; 8-2, second three-port circulator; 9-1, first chirped fiber Bragg grating; 9-2, second chirped fiber Bragg grating; 10-1, first electric field amplitude modulator; 10-2, second electric field amplitude modulator; 11-1, first optical fiber delay line; 11-2, second optical fiber delay line; 12, polarization-maintaining optical fiber; 13, polarization controller; 14, solid polarization beam splitter; 15-1, first detector; 15-2, second detector. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0031] Example 1

[0032] This embodiment provides a fiber soliton modulation system, such as Figure 1 As shown, it includes: a light source module, a modulation module and a detection module;

[0033] The light source module is used to generate an initial optical soliton signal; the light source module includes a mode-locked fiber laser 1, and the mode-locked fiber laser 1 is used to generate an initial optical soliton source;

[0034] The modulation module is connected to the light source module and is used to receive and modulate the initial optical soliton signal; during the modulation process, the pulse waveform and spectrum of the optical soliton in the orthogonal polarization direction are changed by changing the parameters of different types of solitons;

[0035] The detection module is connected to the modulation module and is used to detect the time domain and frequency domain characteristics of the modulated optical soliton in the orthogonal polarization direction, so as to realize data observation and research. The system uses a combination of multiple optical elements to achieve precise control of the optical soliton signal and ensures the optimality of signal modulation through a real-time detection mechanism, thereby significantly improving the efficiency and quality of data transmission.

[0036] In a specific embodiment, when the mode-locked fiber laser 1 is an ytterbium-doped mode-locked fiber laser, the system includes: an ytterbium-doped mode-locked fiber laser, a 1064nm fiber isolator, a first 1064nm fiber collimator, a first λ / 4 wave plate 5-1, a λ / 2 wave plate 6, a second λ / 4 wave plate 5-2, a second 1064nm fiber collimator, a first 1064nm fiber polarization beam splitter, a first 1064nm three-port circulator, a first 1064nm electric field amplitude modulator, a first 1064nm 64nm optical fiber delay line, a second 1064nm three-port circulator, a second 1064nm electric field amplitude modulator, a second 1064nm optical fiber delay line, a second 1064nm optical fiber polarization beam splitter, a polarization controller 13, a third 1064nm optical fiber collimator, a 1064nm solid polarization beam splitter, a first detector 15-1, a second detector 15-2, the first 1064nm three-port circulator and the second 1064nm three-port circulator are respectively provided with chirped fiber Bragg gratings.

[0037] The chirped fiber Bragg grating provides anomalous group velocity dispersion in the 1064nm band, which can independently change the group velocity dispersion experienced by the two branch fiber laser pulses in the fiber soliton modulation system, thereby obtaining fiber solitons with different characteristics in the orthogonal polarization directions at the output end. The adjustment range of the 1064nm fiber delay line is more than 100 picoseconds, and the time delay of a single polarization component can be adjusted so that the pulse after coupling exhibits different polarization state characteristics. If the mode-locked fiber laser operates in other bands, the fiber delay line of the corresponding band needs to be replaced. The three-port circulator supports unidirectional transmission of optical signals. If the mode-locked fiber laser operates in other bands, the three-port circulator of the corresponding band needs to be replaced. The pigtails of the 1064nm fiber polarization beam splitter are HI1060 fiber and PM1060 fiber, which can decompose or couple the orthogonal polarization components of the 1064nm band pulsed laser. If the mode-locked fiber laser operates in other bands, the fiber polarization beam splitter of the corresponding band needs to be replaced.

[0038] In the fiber soliton modulation system, an ytterbium-doped mode-locked fiber laser is used to generate an optical soliton signal in the 1064nm band. The optical fiber isolator 3 is used to limit the direction of light so that the optical signal can only be transmitted in a single direction. The light reflected by the optical fiber echo can be well isolated by the optical fiber isolator 3, which improves the light wave transmission efficiency and effectively avoids the damage of the reflected light signal to the light source. The optical fiber delay line can adjust the time delay in the system so that the optical solitons of the two branches are in a time domain synchronous or asynchronous state. The role of the polarization controller 13 is to change the linear birefringence in the system. The role of the two optical fiber polarization beam splitters is to decompose or couple the orthogonal polarization components of the optical signal. The various components in the fiber soliton modulation system are connected through a standard single-mode optical fiber 2 and a polarization-maintaining optical fiber 12.

[0039] In a specific implementation, the pigtail between the first optical fiber polarization beam splitter 7 - 1 and the second optical fiber polarization beam splitter 7 - 2 is a polarization-maintaining optical fiber 12 , and the other pigtails in the system are all standard single-mode optical fibers 2 .

[0040] In a specific embodiment, the polarization controller 13 is a three-paddle polarization controller. By rotating the three paddles, the linear birefringence in the system can be effectively changed.

[0041] In a specific implementation, the standard single-mode optical fiber 2 is HI1060; the polarization-maintaining optical fiber 12 is PM1060.

[0042] In a specific implementation, the detection module includes: a photodetector, an optical power meter and a spectrum analyzer, which are used to detect the orthogonal components of the modulated solitons.

[0043] Example 2

[0044] This embodiment provides a fiber soliton modulation system, such as Figure 1 As shown, it includes: a light source module, a modulation module and a detection module;

[0045] The light source module is used to generate an initial optical soliton signal; the light source module includes a mode-locked fiber laser 1, and the mode-locked fiber laser 1 is used to generate an initial optical soliton source;

[0046] The modulation module is connected to the light source module and is used to receive and modulate the initial optical soliton signal; during the modulation process, the pulse waveform and spectrum of the optical soliton in the orthogonal polarization direction are changed by changing the parameters of different types of solitons;

[0047] The detection module is connected to the modulation module and is used to detect the time domain and frequency domain characteristics of the modulated optical soliton in the orthogonal polarization direction, so as to realize data observation and research. The system uses a combination of multiple optical elements to achieve precise control of the optical soliton signal and ensures the optimality of signal modulation through a real-time detection mechanism, thereby significantly improving the efficiency and quality of data transmission.

[0048] In a specific embodiment, when the mode-locked fiber laser 1 is an erbium-doped mode-locked fiber laser, the system includes: an erbium-doped mode-locked fiber laser, a 1550nm fiber isolator, a first 1550nm fiber collimator, a first λ / 4 wave plate 5-1, a λ / 2 wave plate 6, a second λ / 4 wave plate 5-2, a second 1550nm fiber collimator, a first 1550nm fiber polarization beam splitter, a first 1550nm three-port circulator, a first 1550nm electric field amplitude modulator, a first 1550nm fiber delay line, a second 1550nm three-port circulator, a second 1550nm electric field amplitude modulator, a first 1550nm fiber delay line, a second 1550nm three-port circulator, a second 1550nm electric field amplitude modulator, a first 1550nm fiber collimator, a first 1550nm fiber polarization beam splitter, a first 1550nm three-port circulator, a first 1550nm electric field amplitude modulator, a first 1550nm fiber delay line, a second 1550nm three-port circulator, a second 1550nm electric field amplitude modulator, a first 1550nm fiber collimator ... Two 1550nm optical fiber delay lines, a second 1550nm optical fiber polarization beam splitter, a polarization controller 13, a third 1550nm optical fiber collimator, a 1550nm solid polarization beam splitter, a first detector 15-1, and a second detector 15-2. The first 1550nm three-port circulator and the second 1550nm three-port circulator are respectively provided with chirped fiber Bragg gratings; if the system operates in the anomalous dispersion band, the first three-port circulator 8-1 and the first chirped fiber Bragg grating 9-1, the second three-port circulator 8-2 and the second chirped fiber Bragg grating 9-2 are replaced by 1550nm dispersion compensating optical fiber.

[0049] In a specific implementation, the pigtail between the first optical fiber polarization beam splitter 7 - 1 and the second optical fiber polarization beam splitter 7 - 2 is a polarization-maintaining optical fiber 12 , and the other pigtails in the system are all standard single-mode optical fibers 2 .

[0050] In a specific embodiment, the polarization controller 13 is a three-paddle polarization controller. By rotating the three paddles, the linear birefringence in the system can be effectively changed.

[0051] In a specific implementation, the standard single-mode optical fiber 2 is SMF-28; the polarization-maintaining optical fiber 12 is PM1550.

[0052] In a specific implementation, the detection module includes: a photodetector, an optical power meter and a spectrum analyzer, which are used to detect the orthogonal components of the modulated solitons.

[0053] Example 3

[0054] This embodiment provides a fiber soliton modulation system, such as Figure 1 As shown, it includes: a light source module, a modulation module and a detection module;

[0055] The light source module is used to generate an initial optical soliton signal; the light source module includes a mode-locked fiber laser 1, and the mode-locked fiber laser 1 is used to generate an initial optical soliton source;

[0056] The modulation module is connected to the light source module and is used to receive and modulate the initial optical soliton signal; during the modulation process, the pulse waveform and spectrum of the optical soliton in the orthogonal polarization direction are changed by changing the parameters of different types of solitons;

[0057] The detection module is connected to the modulation module and is used to detect the time domain and frequency domain characteristics of the modulated optical soliton in the orthogonal polarization direction, so as to realize data observation and research. The system uses a combination of multiple optical elements to achieve precise control of the optical soliton signal and ensures the optimality of signal modulation through a real-time detection mechanism, thereby significantly improving the efficiency and quality of data transmission.

[0058] In a specific embodiment, when the mode-locked fiber laser 1 is a thulium-doped mode-locked fiber laser, the fiber soliton modulation system includes: a thulium-doped mode-locked fiber laser, a 2000nm fiber isolator, a first 2000nm fiber collimator, a first λ / 4 wave plate 5-1, a λ / 2 wave plate 6, a second λ / 4 wave plate 5-2, a second 2000nm fiber collimator, a first 2000nm fiber polarization beam splitter, a first 2000nm three-port circulator, a first 2000nm electric field amplitude modulator, a first 2000nm fiber delay line, which are connected in sequence. , a second 2000nm three-port circulator, a second 2000nm electric field amplitude modulator, a second 2000nm optical fiber delay line, a second 2000nm optical fiber polarization beam splitter, a polarization controller 13, a third 2000nm optical fiber collimator, a 2000nm solid polarization beam splitter, a first detector 15-1, and a second detector 15-2. The first 2000nm three-port circulator and the second 2000nm three-port circulator are respectively provided with chirped fiber Bragg gratings; the chirped fiber Bragg gratings are used to compensate for the normal group velocity dispersion in the system. And the size of the chirp depends on how much the net dispersion value in the system needs to be set. If the system works in the anomalous dispersion band, the first three-port circulator 8-1 and the first chirped fiber Bragg grating 9-1, the second three-port circulator 8-2, and the second chirped fiber Bragg grating 9-2 are replaced by 2000nm dispersion compensation fiber.

[0059] In a specific implementation, the pigtail between the first optical fiber polarization beam splitter 7 - 1 and the second optical fiber polarization beam splitter 7 - 2 is a polarization-maintaining optical fiber 12 , and the other pigtails in the system are all standard single-mode optical fibers 2 .

[0060] In a specific embodiment, the polarization controller 13 is a three-paddle polarization controller. By rotating the three paddles, the linear birefringence in the system can be effectively changed.

[0061] In a specific implementation, the standard single-mode optical fiber 2 is SM1950; the polarization-maintaining optical fiber 12 is PM1950.

[0062] In a specific implementation, the detection module includes: a photodetector, an optical power meter and a spectrum analyzer, which are used to detect the orthogonal components of the modulated solitons.

[0063] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0064] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A fiber soliton modulation system, characterized in that: include: Light source module, modulation module and detection module; The light source module is used to generate an initial optical soliton signal; the light source module comprises a mode-locked fiber laser (1), and the mode-locked fiber laser (1) is used to generate an initial optical soliton source; The modulation module is connected to the light source module and is used to receive and modulate the initial optical soliton signal; In the modulation process, the pulse waveform and spectrum of the optical soliton in the orthogonal polarization direction are changed by changing the parameters of different types of solitons; The detection module is connected to the modulation module and is used to detect the time domain and frequency domain characteristics of the modulated optical soliton in the orthogonal polarization directions, thereby realizing data observation and research.

2. The optical fiber soliton modulation system according to claim 1, characterized in that: The modulation module comprises: an optical fiber isolator (3), a first optical fiber collimator (4-1), a first λ / 4 wave plate (5-1), a λ / 2 wave plate (6), a second λ / 4 wave plate (5-2), a second optical fiber collimator (4-2), a first optical fiber polarization beam splitter (7-1), a first three-port circulator (8-1), a first electric field amplitude modulator (10-1), a first optical fiber delay line (11-1), a second three-port circulator (8-2), a second electric field amplitude modulator (10-2), a second optical fiber delay line (11-2), a second optical fiber polarization beam splitter (7-2), a polarization controller (13), a third optical fiber collimator (4-3), a solid polarization beam splitter (14), a first detector (15-1), and a second detector (15-2), which are connected in sequence. The first three-port circulator (8-1) is provided with a first chirped optical fiber Bragg grating (9-1), and the second three-port circulator (8-2) is provided with a second chirped optical fiber Bragg grating (9-2).

3. The optical fiber soliton modulation system according to claim 1, characterized in that: The mode-locked fiber laser (1) is one of an ytterbium-doped mode-locked fiber laser, an erbium-doped mode-locked fiber laser, and a thulium-doped mode-locked fiber laser.

4. The optical fiber soliton modulation system according to claim 3, characterized in that: When the mode-locked fiber laser (1) is an ytterbium-doped mode-locked fiber laser, the system comprises: an ytterbium-doped mode-locked fiber laser, a 1064nm fiber isolator, a first 1064nm fiber collimator, a first λ / 4 wave plate (5-1), a λ / 2 wave plate (6), a second λ / 4 wave plate (5-2), a second 1064nm fiber collimator, a first 1064nm fiber polarization beam splitter, a first 1064nm three-port circulator, a first 1064nm electric field amplitude modulator, a first 1064nm m optical fiber delay line, a second 1064nm three-port circulator, a second 1064nm electric field amplitude modulator, a second 1064nm optical fiber delay line, a second 1064nm optical fiber polarization beam splitter, a polarization controller (13), a third 1064nm optical fiber collimator, a 1064nm solid polarization beam splitter, a first detector (15-1), and a second detector (15-2), wherein the first 1064nm three-port circulator and the second 1064nm three-port circulator are respectively provided with chirped fiber Bragg gratings.

5. The optical fiber soliton modulation system according to claim 3, characterized in that: When the mode-locked fiber laser (1) is an erbium-doped mode-locked fiber laser, the system comprises: an erbium-doped mode-locked fiber laser, a 1550nm fiber isolator, a first 1550nm fiber collimator, a first λ / 4 wave plate (5-1), a λ / 2 wave plate (6), a second λ / 4 wave plate (5-2), a second 1550nm fiber collimator, a first 1550nm fiber polarization beam splitter, a first 1550nm three-port circulator, a first 1550nm electric field amplitude modulator, a first 1550nm fiber delay line, a second 1550nm three-port circulator, a second 1550nm electric field amplitude modulator, a second 1550nm An optical fiber delay line, a second 1550nm optical fiber polarization beam splitter, a polarization controller (13), a third 1550nm optical fiber collimator, a 1550nm solid polarization beam splitter, a first detector (15-1), and a second detector (15-2); the first 1550nm three-port circulator and the second 1550nm three-port circulator are respectively provided with a chirped fiber Bragg grating; because the system works in an anomalous dispersion band, the first three-port circulator (8-1) and the first chirped fiber Bragg grating (9-1), the second three-port circulator (8-2) and the second chirped fiber Bragg grating (9-2) are replaced by a 1550nm dispersion compensation optical fiber.

6. The optical fiber soliton modulation system according to claim 3, characterized in that: When the mode-locked fiber laser (1) is a thulium-doped mode-locked fiber laser, the fiber soliton modulation system comprises: a thulium-doped mode-locked fiber laser, a 2000nm fiber isolator, a first 2000nm fiber collimator, a first λ / 4 wave plate (5-1), a λ / 2 wave plate (6), a second λ / 4 wave plate (5-2), a second 2000nm fiber collimator, a first 2000nm fiber polarization beam splitter, a first 2000nm three-port circulator, a first 2000nm electric field amplitude modulator, a first 2000nm fiber delay line, a second 2000nm three-port circulator, a second 2000nm electric field amplitude modulator, a second 2000nm fiber delay line, The system comprises a 2000nm optical fiber delay line, a second 2000nm optical fiber polarization beam splitter, a polarization controller (13), a third 2000nm optical fiber collimator, a 2000nm solid polarization beam splitter, a first detector (15-1), and a second detector (15-2); the first 2000nm three-port circulator and the second 2000nm three-port circulator are respectively provided with a chirped optical fiber Bragg grating; since the system operates in an anomalous dispersion band, the first three-port circulator (8-1) and the first chirped optical fiber Bragg grating (9-1), the second three-port circulator (8-2) and the second chirped optical fiber Bragg grating (9-2) are replaced by a 2000nm dispersion compensation optical fiber.

7. The optical fiber soliton modulation system according to claim 2, characterized in that: The pigtail between the first optical fiber polarization beam splitter (7-1) and the second optical fiber polarization beam splitter (7-2) is a polarization-maintaining optical fiber (12), and the other pigtails in the system are all standard single-mode optical fibers (2).

8. The optical fiber soliton modulation system according to claim 2, characterized in that: The polarization controller (13) is a three-paddle polarization controller.

9. The optical fiber soliton modulation system according to claim 7, characterized in that: The standard single-mode optical fiber (2) includes: SMF-28, HI1060 or SM1950; the polarization-maintaining optical fiber (12) includes: PM1550, PM1060 or PM1950; If the mode-locked fiber laser (1) adopts an ytterbium-doped mode-locked fiber laser, a combination of HI1060 and PM1060 is selected; if the mode-locked fiber laser (1) adopts an erbium-doped mode-locked fiber laser, a combination of SMF-28 and PM1550 is selected; if the mode-locked fiber laser (1) adopts a thulium-doped mode-locked fiber laser, a combination of SM1950 and PM1950 is selected.

10. The optical fiber soliton modulation system according to claim 1, characterized in that: The detection module comprises: a photoelectric detector, an optical power meter and a spectrum analyzer, which are used to detect the orthogonal components of the modulated solitons.

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