An optical fiber soliton modulation system

Abstract

The application relates to an optical fiber soliton modulation system, comprising: 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 which 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, the pulse waveform and spectrum of the optical soliton in the orthogonal polarization direction are changed by changing different kinds of soliton parameters; 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 that data observation and research are realized. Compared with the prior art, the application flexibly changes the state of the optical fiber soliton by controlling the cavity-out parameters. After polarization beam splitting, the modulated orthogonal components show unique properties in the time domain and the frequency domain. This greatly expands the current modulation range of the optical fiber soliton.

Description

Technical Field

[0001] This invention relates to the field of nonlinear fiber optics, and in particular to a fiber soliton modulation system. Background Technology

[0002] Mode-locked fiber lasers achieve efficient laser output by modulating repeatedly cyclic optical pulses within a resonant cavity. These optical pulses are affected by various factors within the cavity, including dispersion, loss, gain, nonlinearity, and saturation absorption. In passively mode-locked fiber lasers, the parameter distribution within the cavity varies due to the laser operating in the normal or anomalous dispersion region, and the different components within the fiber resonant cavity. Lasers can generate different types of optical solitons, such as conventional solitons, dissipative solitons, dark solitons, and dispersion-controlled solitons.

[0003] In recent decades, mode-locked fiber lasers have made significant progress in generating ultrashort pulses, leading to their widespread application in fiber optic communication, fiber optic sensing, medical, military, and scientific research. However, mode-locked fiber lasers obtain ultrashort laser pulses through intracavity parameter modulation. Limited by the adjustment range of intracavity parameters, some complex fiber solitons (such as high-order fiber vector solitons) are difficult to obtain directly by building fiber laser oscillators or amplifiers. To address this issue, a new technology is essential. This technology needs greater flexibility and a wider modulation range to effectively optimize the performance of existing systems, alleviate the complexity caused by adjusting design parameters, and thus improve pulse quality and stability. By adopting this approach, lasers can operate under a wider range of conditions, further advancing ultrashort pulse technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies by providing a fiber soliton modulation system that flexibly changes the state of the fiber soliton by controlling external cavity parameters (such as amplitude ratio, time delay, projection angle, phase difference, and pulse chirp). After polarization beam splitting, the modulated orthogonal components exhibit unique properties in both the time and frequency domains. This greatly expands the current modulation range for fiber solitons.

[0005] This invention provides an optical 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 includes a mode-locked fiber laser, which is used to generate the 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 orthogonal polarization directions, thereby enabling data observation and research. This system utilizes a combination of various optical elements to achieve precise control of the optical soliton signal and ensures optimal signal modulation through a real-time detection mechanism, thus significantly improving the efficiency and quality of data transmission.

[0008] Furthermore, the modulation module comprises, in sequence: an optical fiber isolator, a first optical fiber collimator, a first λ / 4 waveplate, a λ / 2 waveplate, a second λ / 4 waveplate, 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-state 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 fibers.

[0009] Specifically, the fiber output port of the mode-locked fiber laser is connected to the fiber input port of the fiber isolator. The fiber output port of the fiber isolator is connected to a waveplate combination consisting of λ / 4, λ / 2, and λ / 4 waveplates via a first fiber collimator. Then, it is connected to the input port of the fiber of the first fiber polarization beamsplitter via a second fiber collimator. The first output port of the first fiber polarization beamsplitter 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 fiber delay line via a first electric field amplitude modulator. The output port of the first fiber delay line is connected to the first input port of the second fiber polarization beamsplitter. The second output port of the first fiber polarization beamsplitter 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 fiber delay line via a second electric field amplitude modulator. The output port of the second fiber delay line is connected to the second input port of the second fiber polarization beamsplitter. The output port of the second fiber polarization beamsplitter is connected to the third fiber collimator via a polarization controller. The first output port of the solid-state polarization beamsplitter is connected to the input port of the first detector. The second output port of the solid-state polarization beamsplitter is connected to the input port of the second detector.

[0010] Furthermore, the mode-locked fiber laser is one of a ytterbium-doped mode-locked fiber laser, an erbium-doped mode-locked fiber laser, or a thulium-doped mode-locked fiber laser. When the passively mode-locked fiber laser is an erbium-doped mode-locked fiber laser or a 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 will also need to be replaced with components for the corresponding wavelength band.

[0011] Furthermore, when the mode-locked fiber laser is a ytterbium-doped mode-locked fiber laser, the system comprises, in sequence: a ytterbium-doped mode-locked fiber laser, a 1064nm fiber isolator, a first 1064nm fiber collimator, a first λ / 4 waveplate, a λ / 2 waveplate, a second λ / 4 waveplate, 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-state polarization beam splitter, a first detector, and a second detector. The first 1064nm three-port circulator and the second 1064nm three-port circulator are respectively provided with chirped fiber Bragg gratings.

[0012] Chirped fiber Bragg gratings provide anomalous group velocity dispersion in the 1064nm band, independently altering the group velocity dispersion experienced by the two branch fiber laser pulses in a fiber soliton modulation system, thereby obtaining fiber solitons with different characteristics in the orthogonal polarization directions at the output. The 1064nm fiber delay line has an adjustment range exceeding hundreds of picoseconds, allowing adjustment of the time delay of a single polarization component, resulting in coupled pulses exhibiting different polarization state characteristics. If the mode-locked fiber laser operates in other bands, the corresponding fiber delay line needs to be replaced. A three-port circulator supports unidirectional transmission of optical signals. If the mode-locked fiber laser operates in other bands, the corresponding three-port circulator needs to be replaced. The 1064nm fiber polarization beamsplitter uses HI1060 and PM1060 fibers as pigtails, capable of decomposing or coupling the orthogonal polarization components of a 1064nm pulsed laser. If the mode-locked fiber laser operates in other bands, the corresponding fiber polarization beamsplitter needs to be replaced.

[0013] In the fiber soliton modulation system, a ytterbium-doped mode-locked fiber laser is used to generate optical soliton signals in the 1064nm band. Fiber isolators restrict the direction of light, ensuring the signal propagates only in a single direction. Light reflected from the fiber optic echo is effectively isolated by the isolators, improving transmission efficiency and preventing damage to the light source from reflected light. Fiber delay lines adjust the time delay within the system, allowing the solitons in the two branches to be in a synchronous or asynchronous state in the time domain. A polarization controller alters the linear birefringence in the system. Two fiber polarization beam splitters decompose or couple the orthogonal polarization components of the optical signal. All components of this fiber soliton modulation system are connected via standard single-mode fiber and polarization-maintaining fiber.

[0014] Furthermore, when the mode-locked fiber laser is an erbium-doped mode-locked fiber laser, the system comprises, in sequence: an erbium-doped mode-locked fiber laser, a 1550nm fiber isolator, a first 1550nm fiber collimator, a first λ / 4 waveplate, a λ / 2 waveplate, a second λ / 4 waveplate, 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, and a second 1550nm electric field amplitude modulator. The system includes a modulator, a second 1550nm fiber delay line, a second 1550nm fiber polarization beam splitter, a polarization controller, a third 1550nm fiber collimator, a 1550nm solid-state polarization beam splitter, a first detector, and a second detector. The first and second 1550nm three-port circulators are each equipped with chirped fiber Bragg gratings. Since the system operates 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 1550nm dispersion-compensating fiber.

[0015] Furthermore, when the mode-locked fiber laser is a thulium-doped mode-locked fiber laser, the fiber soliton modulation system comprises, in sequence: a thulium-doped mode-locked fiber laser, a 2000nm fiber isolator, a first 2000nm fiber collimator, a first λ / 4 waveplate, a λ / 2 waveplate, a second λ / 4 waveplate, 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, and a first 2000nm fiber delay line. The system comprises a second 2000nm three-port circulator, a second 2000nm electric field amplitude modulator, a second 2000nm fiber delay line, a second 2000nm fiber polarization beamsplitter, a polarization controller, a third 2000nm fiber collimator, a 2000nm solid-state polarization beamsplitter, a first detector, and a second detector. The first and second 2000nm three-port circulators are each equipped with chirped fiber Bragg gratings. These chirped fiber Bragg gratings are used to compensate for normal group velocity dispersion within the system. The chirp value depends on the net dispersion value required in the system. Since the system operates in the anomalous dispersion band, the first three-port circulator and the first chirped fiber Bragg grating, as well as the second three-port circulator and the second chirped fiber Bragg grating, are replaced by 2000nm dispersion-compensating fiber.

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

[0017] Furthermore, the polarization controller is a three-propeller polarization controller. By rotating the three propellers, the linear birefringence within the system can be effectively altered.

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

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

[0020] Furthermore, the detection module includes a photodetector, an optical power meter, and a spectrometer, used to detect the orthogonal components of the modulated soliton.

[0021] The working principle of this invention is as follows: First, a soliton emitted from a mode-locked fiber laser passes through an optical fiber isolator, and after being collimated by a first optical fiber collimator, it is incident on a combination of waveplates. The combination of λ / 4, λ / 2, and λ / 4 waveplates allows for flexible adjustment of the soliton's polarization state. Subsequently, the optical signal is received by a second optical fiber collimator and then split by a first optical fiber polarization beamsplitter to separate the orthogonal components of the soliton. These orthogonal components then pass through a first three-port circulator and a second three-port circulator, respectively. The first and second three-port circulators are respectively equipped 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. The orthogonal electric fields of the soliton are modulated by a first optical fiber amplitude modulator and a first optical fiber time delay line, as well as by a second optical fiber amplitude modulator and a second optical fiber time delay line. Afterward, the modulated electric fields are combined using a second polarization beamsplitter, and the polarization state of the modulated soliton is further changed by a polarization controller. Finally, the electric field of the modulated soliton is collimated by a third fiber collimator, and the collimated laser beam is split by a solid-state polarization beam splitter. The first detector and the second detector detect the pulse waveform and spectrum of the modulated soliton in the orthogonal polarization direction, respectively.

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

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

[0024] (2) This invention employs ytterbium-doped mode-locked fiber lasers, erbium-doped mode-locked fiber lasers, and thulium-doped mode-locked fiber lasers. It also selects fiber polarization beam splitters, fiber delay lines, and other components matched to the operating wavelength, effectively obtaining 1.06μm, 1.55μm, and 2μm pulsed fiber lasers. Furthermore, the mode-locked fiber lasers can also operate in other wavelength bands (e.g., the visible light band), but it requires replacing the components corresponding to those wavelengths.

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

[0026] (4) In this 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 in different states at the output end.

[0027] (5) This invention overcomes the current limitations in the study of soliton frequency and time domain characteristics. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of an optical fiber soliton modulation system.

[0029] Reference numerals in the figures: 1. Mode-locked fiber laser; 2. Standard single-mode fiber; 3. Fiber isolator; 4-1. First fiber collimator; 4-2. Second fiber collimator; 4-3. Third fiber collimator; 5-1. First λ / 4 waveplate; 5-2. Second λ / 4 waveplate; 6. λ / 2 waveplate; 7-1. First fiber polarization beamsplitter; 7-2. Second fiber polarization beamsplitter; 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 fiber delay line; 11-2. Second fiber delay line; 12. Polarization-maintaining fiber; 13. Polarization controller; 14. Solid-state polarization beamsplitter; 15-1. First detector; 15-2. Second detector. Detailed Implementation

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

[0031] Example 1

[0032] This embodiment provides an optical 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, which 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 orthogonal polarization directions, thereby enabling data observation and research. This system utilizes a combination of various optical elements to achieve precise control of the optical soliton signal and ensures optimal signal modulation through a real-time detection mechanism, thus significantly improving the efficiency and quality of data transmission.

[0036] In a specific embodiment, when the mode-locked fiber laser 1 is a ytterbium-doped mode-locked fiber laser, the system includes, in sequence: a ytterbium-doped mode-locked fiber laser, a 1064nm fiber isolator, a first 1064nm fiber collimator, a first λ / 4 waveplate 5-1, a λ / 2 waveplate 6, a second λ / 4 waveplate 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, and a first 10... The system includes a 64nm 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 13, a third 1064nm fiber collimator, a 1064nm solid-state polarization beam splitter, a first detector 15-1, and a second detector 15-2. The first 1064nm three-port circulator and the second 1064nm three-port circulator are respectively equipped with chirped fiber Bragg gratings.

[0037] Chirped fiber Bragg gratings provide anomalous group velocity dispersion in the 1064nm band, independently altering the group velocity dispersion experienced by the two branch fiber laser pulses in a fiber soliton modulation system, thereby obtaining fiber solitons with different characteristics in the orthogonal polarization directions at the output. The 1064nm fiber delay line has an adjustment range exceeding hundreds of picoseconds, allowing adjustment of the time delay of a single polarization component, resulting in coupled pulses exhibiting different polarization state characteristics. If the mode-locked fiber laser operates in other bands, the corresponding fiber delay line needs to be replaced. A three-port circulator supports unidirectional transmission of optical signals. If the mode-locked fiber laser operates in other bands, the corresponding three-port circulator needs to be replaced. The 1064nm fiber polarization beamsplitter uses HI1060 and PM1060 fibers as pigtails, capable of decomposing or coupling the orthogonal polarization components of a 1064nm pulsed laser. If the mode-locked fiber laser operates in other bands, the corresponding fiber polarization beamsplitter needs to be replaced.

[0038] In the fiber soliton modulation system, a ytterbium-doped mode-locked fiber laser is used to generate optical soliton signals in the 1064nm band. Fiber isolators 3 restrict the direction of light, ensuring the optical signal can only propagate in a single direction. Light reflected by fiber echoes is effectively isolated by fiber isolators 3, improving optical wave transmission efficiency and preventing damage to the light source from reflected light signals. Fiber delay lines adjust the time delay within the system, allowing the optical solitons in the two branches to be in a time-domain synchronized or asynchronous state. The polarization controller 13 alters the linear birefringence in the system. The two fiber polarization beam splitters decompose or couple the orthogonal polarization components of the optical signal. All components in this fiber soliton modulation system are connected via standard single-mode fiber 2 and polarization-maintaining fiber 12.

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

[0040] In a specific embodiment, the polarization controller 13 is a three-propeller polarization controller. By rotating the three propellers, the linear birefringence within the system can be effectively altered.

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

[0042] In a specific implementation, the detection module includes a photodetector, an optical power meter, and a spectral analyzer, used to detect the orthogonal components of the modulated soliton.

[0043] Example 2

[0044] This embodiment provides an optical 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, which 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 orthogonal polarization directions, thereby enabling data observation and research. This system utilizes a combination of various optical elements to achieve precise control of the optical soliton signal and ensures optimal signal modulation through a real-time detection mechanism, thus 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, in sequence: an erbium-doped mode-locked fiber laser, a 1550nm fiber isolator, a first 1550nm fiber collimator, a first λ / 4 waveplate 5-1, a λ / 2 waveplate 6, a second λ / 4 waveplate 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, and so on. The system comprises two 1550nm fiber delay lines, a second 1550nm fiber polarization beam splitter, a polarization controller 13, a third 1550nm fiber collimator, a 1550nm solid-state polarization beam splitter, a first detector 15-1, and a second detector 15-2. The first and second 1550nm three-port circulators are respectively equipped 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 fiber.

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

[0050] In a specific embodiment, the polarization controller 13 is a three-propeller polarization controller. By rotating the three propellers, the linear birefringence within the system can be effectively altered.

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

[0052] In a specific implementation, the detection module includes a photodetector, an optical power meter, and a spectral analyzer, used to detect the orthogonal components of the modulated soliton.

[0053] Example 3

[0054] This embodiment provides an optical 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, which 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 orthogonal polarization directions, thereby enabling data observation and research. This system utilizes a combination of various optical elements to achieve precise control of the optical soliton signal and ensures optimal signal modulation through a real-time detection mechanism, thus 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 comprises, in sequence: a thulium-doped mode-locked fiber laser, a 2000nm fiber isolator, a first 2000nm fiber collimator, a first λ / 4 waveplate 5-1, a λ / 2 waveplate 6, a second λ / 4 waveplate 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, and a first 2000nm fiber delay line. The system comprises a second 2000nm three-port circulator, a second 2000nm electric field amplitude modulator, a second 2000nm fiber delay line, a second 2000nm fiber polarization beamsplitter, a polarization controller 13, a third 2000nm fiber collimator, a 2000nm solid-state polarization beamsplitter, a first detector 15-1, and a second detector 15-2. The first and second 2000nm three-port circulators are each equipped with a chirped fiber Bragg grating (FBG). The chirped FBG is used to compensate for normal group velocity dispersion within the system. The chirp value depends on the net dispersion value required in the system. If the system operates in the anomalous dispersion band, the first three-port circulator 8-1 and the first chirped FBG 9-1, the second three-port circulator 8-2, and the second chirped FBG 9-2 are replaced by 2000nm dispersion-compensating fiber.

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

[0060] In a specific embodiment, the polarization controller 13 is a three-propeller polarization controller. By rotating the three propellers, the linear birefringence within the system can be effectively altered.

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

[0062] In a specific implementation, the detection module includes a photodetector, an optical power meter, and a spectral analyzer, used to detect the orthogonal components of the modulated soliton.

[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 provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any 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 invention should be within the protection scope of the present invention.

Claims

1. An optical fiber soliton modulation system, characterized by, 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 includes a mode-locked fiber laser (1), which 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; During modulation, the pulse waveform and spectrum of optical solitons in orthogonal polarization directions are changed by altering 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 direction, thereby realizing data observation and research. The modulation module comprises, in sequence: an optical fiber isolator (3), a first optical fiber collimator (4-1), a first λ / 4 waveplate (5-1), a λ / 2 waveplate (6), a second λ / 4 waveplate (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-state polarization beam splitter (14), a first detector (15-1), and a second detector (15-2). The first three-port circulator (8-1) is provided with a first chirped fiber Bragg grating (9-1), and the second three-port circulator (8-2) is provided with a second chirped fiber Bragg grating (9-2).

2. A soliton modulator system as claimed in claim 1, wherein The mode-locked fiber laser (1) is one of the following: ytterbium-doped mode-locked fiber laser, erbium-doped mode-locked fiber laser, and thulium-doped mode-locked fiber laser.

3. A soliton modulator system as claimed in claim 2, wherein When the mode-locked fiber laser (1) is a ytterbium-doped mode-locked fiber laser, the system comprises, in sequence: a ytterbium-doped mode-locked fiber laser, a 1064 nm fiber isolator, a first 1064 nm fiber collimator, a first λ / 4 waveplate (5-1), a λ / 2 waveplate (6), a second λ / 4 waveplate (5-2), a second 1064 nm fiber collimator, a first 1064 nm fiber polarization beamsplitter, a first 1064 nm three-port circulator, a first 1064 nm electric field amplitude modulator, a first 1064 nm fiber delay line, a second 1064 nm three-port circulator, a second 1064 nm electric field amplitude modulator, a second 1064 nm fiber delay line, a second 1064 nm fiber polarization beamsplitter, a polarization controller (13), a third 1064 nm fiber collimator, a 1064 nm solid-state polarization beamsplitter, a first detector (15-1), and a second detector (15-2). The first 1064 nm three-port circulator and the second 1064 nm three-port circulator are each equipped with a chirped fiber Bragg grating.

4. A soliton modulator system as claimed in claim 2, wherein When the mode-locked fiber laser (1) is an erbium-doped mode-locked fiber laser, the system comprises, in sequence: an erbium-doped mode-locked fiber laser, a 1550 nm fiber isolator, a first 1550 nm fiber collimator, a first λ / 4 waveplate (5-1), a λ / 2 waveplate (6), a second λ / 4 waveplate (5-2), a second 1550 nm fiber collimator, a first 1550 nm fiber polarization beamsplitter, a first 1550 nm three-port circulator, a first 1550 nm electric field amplitude modulator, a first 1550 nm fiber delay line, a second 1550 nm three-port circulator, a second 1550 nm electric field amplitude modulator, a second 1550 nm fiber delay line, a second 1550 nm fiber polarization beamsplitter, a polarization controller (13), a third 1550 nm fiber collimator, a 1550 nm solid-state polarization beamsplitter, a first detector (15-1), and a second detector (15-2). The first 1550 nm three-port circulator and the second 1550 nm three-port circulator are each equipped with a chirped fiber Bragg grating. Since 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 1550 nm dispersion-compensating fiber.

5. A soliton modulator system as claimed in claim 2, wherein, When the mode-locked fiber laser (1) is a thulium-doped mode-locked fiber laser, the fiber soliton modulation system comprises, in sequence: a thulium-doped mode-locked fiber laser, a 2000 nm fiber isolator, a first 2000 nm fiber collimator, a first λ / 4 waveplate (5-1), a λ / 2 waveplate (6), a second λ / 4 waveplate (5-2), a second 2000 nm fiber collimator, a first 2000 nm fiber polarization beamsplitter, a first 2000 nm three-port circulator, a first 2000 nm electric field amplitude modulator, a first 2000 nm fiber delay line, a second 2000 nm three-port circulator, a second 2000 nm electric field amplitude modulator, a second 2000 nm fiber delay line, a second 2000 nm fiber polarization beamsplitter, a polarization controller (13), a third 2000 nm fiber collimator, a 2000 nm solid-state polarization beamsplitter, a first detector (15-1), and a second detector (15-2). The first 2000 nm three-port circulator and the second 2000 nm three-port circulator are each equipped with a chirped fiber Bragg grating. Since 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 2000 nm dispersion-compensating fiber.

6. A soliton modulator system as claimed in claim 1, wherein, The pigtail between the first fiber polarization beam splitter (7-1) and the second fiber polarization beam splitter (7-2) is a polarization-maintaining fiber (12), and the other pigtails in the system are all standard single-mode fibers (2).

7. A soliton modulator system as claimed in claim 1, wherein, The polarization controller (13) is a three-paddle polarization controller.

8. The fiber optic soliton modulation system according to claim 6, characterized in that, The standard single-mode fiber (2) includes: SMF-28, HI1060 or SM1950; the polarization-maintaining fiber (12) includes: PM1550, PM1060 or PM1950; If the mode-locked fiber laser (1) is a ytterbium-doped mode-locked fiber laser, then the combination of HI1060 and PM1060 is selected; if the mode-locked fiber laser (1) is an erbium-doped mode-locked fiber laser, then the combination of SMF-28 and PM1550 is selected; if the mode-locked fiber laser (1) is a thulium-doped mode-locked fiber laser, then the combination of SM1950 and PM1950 is selected.

9. The optical soliton modulation system of claim 1, wherein, The detection module includes a photodetector, an optical power meter, and a spectrometer, used to detect the orthogonal components of the modulated soliton.

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