Domain wall generating device, laser, and domain wall generating method

Abstract

The application discloses a domain wall generating device, a laser and a domain wall generating method. The domain wall generating device comprises an optical signal modulation assembly and an optical fiber ring resonant cavity. The optical signal modulation assembly comprises a continuous optical fiber laser and a first polarization controller connected with each other. The optical fiber ring resonant cavity comprises an optical fiber ring, a first coupler and a second coupler. The optical fiber ring comprises a first polarization maintaining optical fiber and a second polarization maintaining optical fiber connected in a head-to-tail mode along the circumference of the optical fiber ring. The length of the first polarization maintaining optical fiber is the same as that of the second polarization maintaining optical fiber. The fast axis of the first polarization maintaining optical fiber corresponds to the slow axis of the second polarization maintaining optical fiber, and the slow axis of the first polarization maintaining optical fiber corresponds to the fast axis of the second polarization maintaining optical fiber. The first coupler is connected with the first polarization maintaining optical fiber and the first polarization controller. The second coupler is connected with the first polarization maintaining optical fiber and the second polarization maintaining optical fiber. In this way, the influence of the birefringence effect in the optical fiber is eliminated, the two polarization modes are symmetrical in the strong birefringence optical fiber, the domain wall is formed, and the structure is simple.

Description

Technical Field

[0001] This invention relates to the field of optical fiber technology, and specifically to an optical domain wall generation device, a laser, and a method for generating optical domain walls. Background Technology

[0002] Optical domain walls, borrowing the concept of magnetic domains from magnetism, are self-localized topological defects that can connect two stable states in a physical system. Domain walls discovered in optics have been shown to connect two polarization modes, and these modes can be interchanged through domain wall structures. Haelterman and Sheppard introduced the concept of domain wall solitons by describing isolated homogeneous domains of orthogonally polarized states propagating in vectors, and by demonstrating resistance to (lateral) diffraction or (time) dispersion propagation in Kerr media. Subsequent experiments verified the existence of domain wall solitons and demonstrated the advantages of polarization domain walls in transmission. Experiments showed that domain walls have advantages in long-distance distortion-free transmission, and data transmission using the soliton properties of domain walls exceeds the limitations caused by typical Kerr nonlinearities. The phase of the domain wall can also be used for encoding within each domain to increase the bit rate. Due to the special topological properties of domain walls, polarization domain walls are robust to noise and nonlinear impairments. The robustness of domain walls can find many applications in optical communication, high-power pulse propagation, all-optical processing, data storage, and optical domain wall generation devices. Polarization separation can also be used for chaotic-based optical data transmission, showing great promise for applications.

[0003] However, domain walls are highly sensitive to fiber birefringence, and observation of domain walls has only been achieved in near-zero birefringence fibers. Since fiber birefringence is difficult to eliminate, other methods need to be considered to mitigate its effects. This is mainly achieved by adding a polarization controller to the resonant cavity to control parameters and eliminate the influence of birefringence on domain walls. However, this approach suffers from difficulties in parameter adjustment and control, as well as complex and expensive equipment. Summary of the Invention

[0004] The main objective of this invention is to provide an optical domain wall generation device, a laser, and a method for generating optical domain walls, in order to solve the aforementioned problems.

[0005] To achieve the above objectives, the present invention provides an optical domain wall generation device, the optical domain wall generation device comprising: An optical signal modulation component includes a continuous fiber laser and a first polarization controller connected to each other. The continuous fiber laser is used to output a continuous optical signal, and the first polarization controller is used to adjust the polarization state of the continuous optical signal, such that the continuous optical signal is divided into a TE mode optical signal and a TM mode optical signal with orthogonal polarization states; and... The fiber optic ring resonator includes a fiber optic ring, a first coupler, and a second coupler. The fiber optic ring includes a first polarization-maintaining fiber and a second polarization-maintaining fiber connected end-to-end along its circumference. The lengths of the first and second polarization-maintaining fibers are the same, and the fast axis of the first and second polarization-maintaining fibers corresponds to the slow axis of the second polarization-maintaining fiber, and vice versa. The first coupler is connected to the first polarization-maintaining fiber and the first polarization controller to couple a portion of the continuous optical signal input from the first polarization controller into the fiber optic ring for oscillation. The second coupler is connected to the first and second polarization-maintaining fibers to output the continuous optical signal after oscillation by the fiber optic ring.

[0006] Optionally, the operating wavelength of the continuous fiber laser is 1550 nm.

[0007] Optionally, the optical signal modulation component further includes an intensity modulator, an erbium-doped fiber amplifier, an optical isolator, an optical bandpass filter, and a pulse mode generator. The continuous fiber laser, the intensity modulator, the erbium-doped fiber amplifier, the optical isolator, the optical bandpass filter, and the first polarization controller are connected in sequence via single-mode fiber, and the pulse mode generator is connected to the intensity modulator via single-mode fiber.

[0008] Optionally, the fiber optic ring resonator is connected to the optical signal modulation component via a single-mode fiber.

[0009] Optionally, the optical bandpass filter is a narrowband bandpass tunable optical filter.

[0010] Optionally, the optical domain wall generation device further includes a feedback control component, which includes a photodetector and a proportional-differential-integral controller connected together. The photodetector is connected to the first coupler, and the proportional-differential-integral controller is connected to the optical signal modulation component.

[0011] Optionally, the optical domain wall generation device further includes a polarization mode separation component. The polarization mode separation component includes a third coupler, a second polarization controller, and a polarization beam splitter connected in sequence. The third coupler is connected to the second coupler and is used to split the continuous optical signal input through the second coupler into two optical signals. One optical signal is the total optical field, and the other optical signal is transmitted sequentially to the second polarization controller and the polarization beam splitter, and then split into the TE mode optical signal and the TM mode optical signal by the polarization beam splitter.

[0012] Optionally, the splitting ratio of the first coupler is 90 / 10; The splitting ratio of the second coupler is 99 / 1; The splitting ratio of the third coupler is 70 / 30.

[0013] The present invention also provides a laser, including an optical domain wall generation device; The optical domain wall generation device includes: An optical signal modulation component includes a continuous fiber laser and a first polarization controller connected to each other. The continuous fiber laser is used to output a continuous optical signal, and the first polarization controller is used to adjust the polarization state of the continuous optical signal, such that the continuous optical signal is divided into a TE mode optical signal and a TM mode optical signal with orthogonal polarization states; and... The fiber optic ring resonator includes a fiber optic ring, a first coupler, and a second coupler. The fiber optic ring includes a first polarization-maintaining fiber and a second polarization-maintaining fiber connected end-to-end along its circumference. The lengths of the first and second polarization-maintaining fibers are the same, and the fast axis of the first and second polarization-maintaining fibers corresponds to the slow axis of the second polarization-maintaining fiber, and vice versa. The first coupler is connected to the first polarization-maintaining fiber and the first polarization controller to couple a portion of the continuous optical signal input from the first polarization controller into the fiber optic ring for oscillation. The second coupler is connected to the first and second polarization-maintaining fibers to output the continuous optical signal after oscillation by the fiber optic ring.

[0014] The present invention also provides a method for generating optical domain walls, using the above-described optical domain wall generation apparatus, the method comprising the following steps: Drive a continuous fiber laser to generate a continuous optical signal; The first polarization controller is driven to adjust the polarization state of the continuous optical signal to divide the continuous optical signal into TE mode optical signal and TM mode optical signal with orthogonal polarization states, and output to the first coupler to input another part of the continuous optical signal into the feedback control component. The input continuous optical signal is split into two parts by the first coupler, and one part of the continuous optical signal is coupled to the fiber ring oscillation. The continuous optical signal after being oscillated by the fiber ring is output to the third coupler through the second coupler, and the third coupler splits the input continuous optical signal into two optical signals. One of the two optical signals is the total optical field, and the other optical signal is transmitted to the polarization mode separation component. The second polarization controller is driven to adjust the polarization state of the optical signal, and the optical signal is split into the TE mode optical signal and the TM mode optical signal by the polarization beam splitter; The time-domain waveforms of the TE mode optical signal, the TM mode optical signal, and the total optical field are acquired. If the time-domain waveforms of the TE mode optical signal and the TM mode optical signal are symmetrical, and there is energy exchange between the TE mode optical signal and the TM mode optical signal, and the energy of the total optical field is constant, then the generation of optical domain walls is confirmed. Otherwise, the generation of optical domain walls is confirmed, and the frequency of the continuous optical signal is adjusted.

[0015] In the technical solution of this invention, the propagation speeds of TE mode optical signals and TM mode optical signals with orthogonal polarization states are inconsistent in the fast and slow axes of the optical fiber ring. This avoids excessively large group velocity differences between orthogonally polarized optical signals accumulated in the loop. By setting up a resonant cavity formed by the first polarization-maintaining fiber and the second polarization-maintaining fiber, the influence of birefringence in the optical fiber is eliminated. Although birefringence exists locally in the optical fiber ring, the overall birefringence of the optical fiber ring is almost zero. This allows the two polarization modes to remain symmetrical in a strongly birefringent fiber, thereby forming an optical domain wall. In addition, compared with the existing design that eliminates the influence of birefringence by setting a polarization controller in the resonant cavity of the optical fiber ring, the optical domain wall generation device provided by this invention achieves optical domain wall generation by designing the structure of the optical fiber ring. Its structure is simple and the generation cost is low. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of an embodiment of the optical domain wall generation device provided by the present invention; Figure 2 for Figure 1 A schematic diagram of the fiber ring structure of the optical domain wall generation device; Figure 3 for Figure 1 A schematic diagram of the time-domain waveform of the continuous optical signal emitted by the continuous fiber laser of the domain wall generation device after 100 loops. Figure 4 for Figure 3 A schematic diagram illustrating the evolution process of a continuous optical signal undergoing a loop. Figure 5 This is a flowchart of an embodiment of the optical domain wall generation method provided by the present invention.

[0018] Explanation of icon numbers:

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] Optical domain walls, borrowing the concept of magnetic domains from magnetism, are self-localized topological defects that can connect two stable states in a physical system. Domain walls discovered in optics have been shown to connect two polarization modes, and these modes can be interchanged through domain wall structures. Haelterman and Sheppard introduced the concept of domain wall solitons by describing isolated homogeneous domains of orthogonally polarized states propagating in vectors, and by demonstrating resistance to (lateral) diffraction or (time) dispersion propagation in Kerr media. Subsequent experiments verified the existence of domain wall solitons and demonstrated the advantages of polarization domain walls in transmission. Experiments showed that domain walls have advantages in long-distance distortion-free transmission, and data transmission using the soliton properties of domain walls exceeds the limitations caused by typical Kerr nonlinearities. The phase of the domain wall can also be used for encoding within each domain to increase the bit rate. Due to the special topological properties of domain walls, polarization domain walls are robust to noise and nonlinear impairments. The robustness of domain walls can find many applications in optical communication, high-power pulse propagation, all-optical processing, data storage, and optical domain wall generation devices. Polarization separation can also be used for chaotic-based optical data transmission, showing great promise for applications.

[0024] However, domain walls are highly sensitive to fiber birefringence, and observation of domain walls has only been achieved in near-zero birefringence fibers. Since fiber birefringence is difficult to eliminate, other methods need to be considered to mitigate its effects. This is mainly achieved by adding a polarization controller to the resonant cavity to control parameters and eliminate the influence of birefringence on domain walls. However, this approach suffers from difficulties in parameter adjustment and control, as well as complex and expensive equipment.

[0025] In view of this, the present invention provides an optical domain wall generation device 100. Figure 1 and Figure 2 This is an embodiment of the optical domain wall generation device 100 provided by the present invention.

[0026] Please see Figure 1 and Figure 2The optical domain wall generation device 100 includes an optical signal modulation component 1 and an optical fiber ring resonator 2. The optical signal modulation component 1 includes a continuous fiber laser 11 and a first polarization controller 12 connected together. The continuous fiber laser 11 is used to output a continuous optical signal, and the first polarization controller 12 is used to adjust the polarization state of the continuous optical signal, so that the continuous optical signal is divided into a TE mode optical signal and a TM mode optical signal with orthogonal polarization states. The optical fiber ring resonator 2 includes an optical fiber ring 21, a first coupler 22 and a second coupler 23. The optical fiber ring 21 includes a first polarization-maintaining fiber 211 and a second polarization-maintaining fiber 212 connected end-to-end along its circumference. The length of the first polarization-maintaining fiber 211 is the same as the length of the second polarization-maintaining fiber 212, and the fast axis of the first polarization-maintaining fiber 211 corresponds to the slow axis of the second polarization-maintaining fiber 212, and the slow axis of the first polarization-maintaining fiber 211 corresponds to the fast axis of the second polarization-maintaining fiber 212. The first coupler 22 is connected to the first polarization-maintaining fiber 211 and the first polarization controller 12 to couple a portion of the continuous optical signal input from the first polarization controller 12 to oscillate within the fiber loop 21. The second coupler 23 is connected to the first polarization-maintaining fiber 211 and the second polarization-maintaining fiber 212 to output the continuous optical signal after oscillation through the fiber loop 21.

[0027] In the technical solution of this invention, when the continuous fiber laser 11 is driven to emit a continuous optical signal, the continuous optical signal is split into a TE mode optical signal and a TM mode optical signal with orthogonal polarization states by the first polarization controller 12, and output to the first coupler 22. The first coupler 22 couples a portion of the continuous optical signal to the fiber ring 21 for oscillation. At this time, since the fiber ring 21 includes a first polarization-maintaining fiber 211 and a second polarization-maintaining fiber 212, both of which have fast and slow axes, the continuous optical signal has two polarization states. When the continuous optical signal oscillates in the fiber ring 21, the polarization state of the continuous optical signal has... The transmission method employs two modes: fast-axis transmission and slow-axis transmission. Specifically, one of the two polarization states of the continuous optical signal is transmitted via the fast axis, and the other via the slow axis. The lengths of the first polarization-maintaining fiber 211 and the second polarization-maintaining fiber 212 are the same, and the fast axis of the first polarization-maintaining fiber 211 corresponds to the slow axis of the second polarization-maintaining fiber 212, and vice versa. Thus, when the continuous optical signal is transmitted from the output end of the first polarization-maintaining fiber 211 to the input end of the second polarization-maintaining fiber 212, the polarization of the continuous optical signal transmitted via the slow axis in the first polarization-maintaining fiber 211 is... The polarization state of the continuous optical signal is converted to fast-axis transmission in the second polarization-maintaining fiber 212, and the polarization state of the continuous optical signal transmitted through the fast axis in the first polarization-maintaining fiber 211 is converted to slow-axis transmission in the second polarization-maintaining fiber 212. Similarly, when the continuous optical signal is transmitted from the output end of the second polarization-maintaining fiber 212 to the input end of the first polarization-maintaining fiber 211, the transmission mode of the two polarization states of the continuous optical signal will also be converted accordingly, which will not be elaborated here. In this way, the optical domain wall generation device 100 provided by the present invention utilizes the characteristic that the propagation speeds of the TE mode optical signal and the TM mode optical signal with orthogonal polarization states are inconsistent in the fast and slow axes of the optical fiber ring 21 to avoid To avoid excessive accumulation of group velocity differences between orthogonally polarized light signals, the resonant cavity formed by the first and second polarization-maintaining fibers is used to eliminate the influence of birefringence in the fiber. This ensures that although birefringence exists locally in the fiber ring, the overall birefringence of the fiber ring is almost zero, thus allowing the two polarization modes to remain symmetrical in the strongly birefringent fiber, thereby forming an optical domain wall. In addition, compared with the existing design that eliminates the influence of birefringence by setting a polarization controller in the resonant cavity of the fiber ring, the optical domain wall generation device 100 provided by this invention achieves optical domain wall generation by designing the structure of the fiber ring 21, which has a simple structure and low generation cost.

[0028] It should be noted that, in this invention, specifically by rotating the first polarization-maintaining fiber 211 by 90° or the second polarization-maintaining fiber 212 by 90°, the first polarization-maintaining fiber 211 and the second polarization-maintaining fiber 212 are spliced ​​in a staggered manner, thereby achieving the correspondence between the fast axis of the first polarization-maintaining fiber 211 and the slow axis of the second polarization-maintaining fiber 212, and the correspondence between the slow axis of the first polarization-maintaining fiber 211 and the fast axis of the second polarization-maintaining fiber 212.

[0029] It should also be noted that, in one embodiment of the present invention, the first polarization-maintaining fiber 211 and the second polarization-maintaining fiber 212 are polarization-maintaining dispersion compensation fibers, the total length of the first polarization-maintaining fiber 211 and the second polarization-maintaining fiber 212 is 85m, the length of the first polarization-maintaining fiber 211 and the second polarization-maintaining fiber 212 is 42.5cm, and they have the same nonlinear coefficient γ = 5.5W. -1 ·km -1 The same second-order dispersion coefficient β2 = 1.275 ps 2 / m, cross-phase modulation coefficient B=2, fiber loss 9.21×10 -5 m -1 Group delay difference Δβ = 3 × 10 -12 s / m, polarization beat length L B =5×10 -3 m -1 W -1 The loss at the fiber optic junction is ρ=0.03. The detuning difference between the two orthogonal polarization states in the polarization-maintaining fiber is Δδ≈0. The loop detuning of the polarization mode relative to the nearest resonance peak of the pump is δ1=δ2=0.3. The free spectral range of the fiber ring 21 is 2.39MHz.

[0030] It should also be noted that the first polarization controller 12 is used to adjust the power of the TE mode optical signal and the TM mode optical signal, i.e., the splitting ratio, to a suitable polarization angle (45 degrees) so that the power of the TE mode optical signal and the TM mode optical signal are equal. More specifically, the first polarization controller 12 includes a mechanical polarization controller, a waveplate polarization controller, and a Faraday effect-based polarization rotator.

[0031] Furthermore, in this invention, the fiber ring 21 acts as a narrow-bandwidth comb filter and resonates with the continuous optical signal generated by the continuous fiber laser 11. More specifically, in one embodiment of this invention, the operating wavelength of the continuous fiber laser 11 is 1550nm.

[0032] For details, please refer to Figure 1The optical signal modulation component 1 further includes an intensity modulator 13, an erbium-doped fiber amplifier 14, an optical isolator 15, an optical bandpass filter 16, and a pulse mode generator 17. The continuous fiber laser 11, the intensity modulator 13, the erbium-doped fiber amplifier 14, the optical isolator 15, the optical bandpass filter 16, and the first polarization controller 12 are sequentially connected via a single-mode fiber 5. The pulse mode generator 17 is connected to the intensity modulator 13 via a single-mode fiber 5. Specifically, the output end of the continuous fiber laser 11 is connected to the input end of the intensity modulator 13, the output end of the intensity modulator 13 is connected to the input end of the erbium-doped fiber amplifier 14, the output end of the erbium-doped fiber amplifier 14 is connected to the input end of the optical isolator 15, the output end of the optical isolator 15 is connected to the input end of the optical bandpass filter 16, and the output end of the optical bandpass filter 16 is connected to the input end of the first polarization controller 12.

[0033] The intensity modulator 13 is used to modulate the continuous optical signal emitted by the continuous fiber laser 11 to generate a super-Gaussian pulse; the erbium-doped fiber amplifier 14 is used to amplify the power of the continuous optical signal, specifically, to amplify the power of the continuous optical signal to a peak power of 15W; the optical isolator 15 is a unidirectional channel used to prevent light from propagating in the opposite direction; the optical bandpass filter 16 is used to suppress amplified spontaneous emission noise; and the pulse mode generator 17 is used to drive the intensity modulator 13 to generate a 1.1ns flat-top pulse.

[0034] Furthermore, the fiber optic ring resonator 2 is connected to the optical signal modulation assembly 1 via a single-mode fiber 5. For details, please refer to [link to relevant documentation]. Figure 1 The output of the first polarization controller 12 is connected to the first coupler 22 through the single-mode optical fiber 5.

[0035] Specifically, the optical bandpass filter 16 is a narrowband bandpass adjustable optical filter.

[0036] For details, please refer to Figure 1The optical domain wall generation device 100 further includes a feedback control component 3, which includes a photodetector 31 and a proportional-derivative-integral (PID) controller 32 connected to each other. The photodetector 31 is connected to the first coupler 22, and the PID controller 32 is connected to the optical signal modulation component 1. That is, the first coupler 22 will split part of the energy of the input continuous optical signal and transmit it to the photodetector 31. The frequency of the continuous optical signal can be adjusted by adjusting the parameters of each device in the optical signal modulation component 1. Then, the PID controller 32 will feedback and lock the adjusted frequency of the continuous optical signal, so that the optical domain wall formed by the fiber ring 21 is stably generated.

[0037] More specifically, the first coupler 22, the photodetector 31, and the proportional-differential-integral controller 32 are connected in sequence via a single-mode optical fiber 5.

[0038] Further, please refer to Figure 1 The optical domain wall generation device 100 further includes a polarization mode separation component 4. The polarization mode separation component 4 includes a third coupler 41, a second polarization controller 42, and a polarization beam splitter 43 connected in sequence. The third coupler 41 is connected to the second coupler 23. The third coupler 41 is used to split the continuous optical signal input through the second coupler 23 into two optical signals. One optical signal is the total optical field, and the other optical signal is transmitted sequentially to the second polarization controller 42 and the polarizer, and then split into the TE mode optical signal and the TM mode optical signal by the polarization beam splitter 43. The polarization mode separation component 4 is used to detect whether the optical domain wall generation device 100 generates an optical domain wall. Specifically, a power map can be obtained by detecting the total optical field, the TE mode optical signal, and the TM mode optical signal. Figure 3 and Figure 4 As shown, where, Figure 3 Curve 1 represents the time-domain waveform of the TE mode optical signal, curve 2 represents the time-domain waveform of the TM mode optical signal, and curve 3 represents the time-domain waveform of the total optical field. Figure 4 Figure (a) shows the evolution of the total optical field within one loop, Figure (b) shows the evolution of the TE mode optical signal within one loop, and Figure (c) shows the evolution of the TM mode optical signal within one loop. From the figures, it can be seen that the time-domain waveform of the TE mode optical signal (curve 1) and the time-domain waveform of the TM mode optical signal (curve 2) are mirror-symmetric, and there is energy exchange between the TE mode optical signal and the TM mode optical signal. Furthermore, the total optical field energy is constant, which confirms the generation of the optical domain wall.

[0039] Furthermore, in one embodiment of the present invention, the splitting ratio of the first coupler 22 is 90 / 10, that is, the first coupler 22 couples 10% of the energy of the input optical signal to the optical fiber ring 21 for oscillation, while the other 90% of the energy is transmitted to the feedback control component 3 for adjustment.

[0040] The splitting ratio of the second coupler 23 is 99 / 1, meaning that the second coupler 23 outputs 99% of the energy of the optical signal oscillating in the optical fiber ring 21 to the third coupler 41.

[0041] The splitting ratio of the third coupler 41 is 70 / 30, meaning that the third coupler 41 transmits 70% of the energy of the input optical signal to the polarization beam splitter 43 for separation, while the other 30% of the energy is the total optical field.

[0042] The present invention also provides a laser, which includes an optical domain wall generating device 100. It should be noted that the optical domain wall generating device 100 is the same as described above; that is, the laser has all the technical features of all embodiments of the optical domain wall generating device 100 described above, and thus possesses all the technical effects brought about by all the above-described technical features, which will not be elaborated further here.

[0043] This invention also provides a method for generating optical domain walls; please refer to [link / reference]. Figure 5 The optical domain wall generation method employs the aforementioned optical domain wall generation apparatus and includes the following steps: Step S100: Drive the continuous fiber laser to generate a continuous optical signal; Step S200: Drive the first polarization controller to adjust the polarization state of the continuous optical signal to divide the continuous optical signal into TE mode optical signal and TM mode optical signal with intersecting polarization states, and output them to the first coupler; Step S300: The input continuous optical signal is divided into two parts by the first coupler, and one part of the continuous optical signal is coupled to the fiber ring oscillation, while the other part of the continuous optical signal is input to the feedback control component. In this step, a portion of the continuous optical signal generates optical domain walls through oscillation in the optical fiber ring, while another portion of the continuous optical signal is used by the feedback control component to lock the frequency of the continuously adjusted optical signal, thereby stabilizing the formation of the optical domain walls.

[0044] Step S400: The continuous optical signal after the fiber ring oscillation is output to the third coupler through the second coupler, and is split into two optical signals through the third coupler. One of the two optical signals is the total optical signal, and the other optical signal is transmitted to the polarization mode separation component. In this step, two optical signals are used to detect whether the optical domain walls are generated.

[0045] Step S500: Drive the second polarization controller to adjust the polarization state of the optical signal, and split it into the TE mode optical signal and the TM mode optical signal through the polarization beam splitter; Step S600: Obtain the time-domain waveform of the TE mode optical signal, the time-domain waveform of the TM mode optical signal, and the time-domain waveform of the total optical field. If the time-domain waveforms of the TE mode optical signal and the TM mode optical signal are symmetrical, and there is energy exchange between the TE mode optical signal and the TM mode optical signal, and the energy of the total optical field is constant, then confirm that the optical domain wall is generated; otherwise, confirm that the optical domain wall is not generated, and adjust the frequency of the continuous optical signal.

[0046] In this step, when the polarization mode separation component detects and confirms the formation of an optical domain wall, the feedback control component locks the frequency of the continuously modulated optical signal to ensure the stable formation of the optical domain wall. When the polarization mode separation component detects and confirms that the optical domain wall has not been formed, the frequency of the continuously modulated optical signal is adjusted by adjusting the parameters of each device in the optical signal modulation component until the optical domain wall is formed.

[0047] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A device for generating optical domain walls, characterized in that, The optical domain wall generation device includes: An optical signal modulation component includes a continuous fiber laser and a first polarization controller connected to each other. The continuous fiber laser is used to output a continuous optical signal, and the first polarization controller is used to adjust the polarization state of the continuous optical signal, such that the continuous optical signal is divided into a TE mode optical signal and a TM mode optical signal with orthogonal polarization states; and... An optical fiber ring resonator includes an optical fiber ring, a first coupler, and a second coupler. The optical fiber ring includes a first polarization-maintaining fiber and a second polarization-maintaining fiber connected end-to-end along its circumference. The lengths of the first polarization-maintaining fiber and the second polarization-maintaining fiber are the same, and the fast axis of the first polarization-maintaining fiber corresponds to the slow axis of the second polarization-maintaining fiber, and vice versa. The first coupler is connected to the first polarization-maintaining fiber and the first polarization controller to couple a portion of the continuous optical signal input from the first polarization controller into the optical fiber ring for oscillation. The second coupler is connected to the first polarization-maintaining fiber and the second polarization-maintaining fiber to output the continuous optical signal after oscillation by the optical fiber ring. The optical signal modulation component further includes an intensity modulator, an erbium-doped fiber amplifier, an optical isolator, an optical bandpass filter, and a pulse mode generator. The continuous fiber laser, the intensity modulator, the erbium-doped fiber amplifier, the optical isolator, the optical bandpass filter, and the first polarization controller are connected in sequence via single-mode fiber. The pulse mode generator is connected to the intensity modulator via single-mode fiber. The optical isolator is a unidirectional channel used to prevent light from propagating in the opposite direction; The optical domain wall generation device further includes a feedback control component, which includes a photodetector and a proportional-differential-integral controller connected together. The photodetector is connected to the first coupler, and the proportional-differential-integral controller is connected to the optical signal modulation component. The optical domain wall generation device further includes a polarization mode separation component, which includes a third coupler, a second polarization controller, and a polarization beam splitter connected in sequence. The third coupler is connected to the second coupler and is used to split the continuous optical signal input through the second coupler into two optical signals. One optical signal is the total optical field, and the other optical signal is transmitted sequentially to the second polarization controller and the polarization beam splitter, and then split into the TE mode optical signal and the TM mode optical signal by the polarization beam splitter. The splitting ratio of the first coupler is 90 / 10; The splitting ratio of the second coupler is 99 / 1; The splitting ratio of the third coupler is 70 / 30.

2. The optical domain wall generation apparatus as described in claim 1, characterized in that, The operating wavelength of the continuous fiber laser is 1550nm.

3. The optical domain wall generation apparatus as described in claim 1, characterized in that, The fiber optic ring resonator is connected to the optical signal modulation component via a single-mode fiber.

4. The optical domain wall generation apparatus as described in claim 1, characterized in that, The optical bandpass filter is a narrowband bandpass adjustable optical filter.

5. A laser, characterized in that, Includes the optical domain wall generation apparatus as described in any one of claims 1-4.

6. A method for generating optical domain walls, employing the optical domain wall generation apparatus as described in claim 1, characterized in that, The method for generating optical domain walls includes the following steps: Drive a continuous fiber laser to generate a continuous optical signal; The first polarization controller is driven to adjust the polarization state of the continuous optical signal to divide the continuous optical signal into TE mode optical signal and TM mode optical signal with orthogonal polarization states, and output to the first coupler to input another part of the continuous optical signal into the feedback control component. The input continuous optical signal is split into two parts by the first coupler, and one part of the continuous optical signal is coupled to the fiber ring oscillation. The continuous optical signal after being oscillated by the fiber ring is output to the third coupler through the second coupler, and the third coupler splits the input continuous optical signal into two optical signals. One of the two optical signals is the total optical field, and the other optical signal is transmitted to the polarization mode separation component. The second polarization controller is driven to adjust the polarization state of the optical signal, and the optical signal is split into the TE mode optical signal and the TM mode optical signal by the polarization beam splitter. The time-domain waveforms of the TE mode optical signal, the TM mode optical signal, and the total optical field are acquired. If the time-domain waveforms of the TE mode optical signal and the TM mode optical signal are symmetrical, and there is energy exchange between the TE mode optical signal and the TM mode optical signal, and the energy of the total optical field is constant, then the generation of optical domain walls is confirmed. Otherwise, the generation of optical domain walls is confirmed, and the frequency of the continuous optical signal is adjusted.

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