A device and method for coinciding 0th-order light and diffracted light based on an acousto-optic modulator

Abstract

This invention provides a device and method for coinciding zero-order light and diffracted light based on an acousto-optic modulator. A first optical path transmission path is formed between the light source and the first optical path port of the acousto-optic modulator. The fundamental frequency light is transmitted to the acousto-optic modulator after preprocessing. A second optical path transmission path is formed between the second optical path port of the acousto-optic modulator and a first high-reflection mirror. A first convex lens is also provided in the second optical path transmission path. The zero-order light output by the acousto-optic modulator and the diffracted light are refracted by the first convex lens to form two parallel beams. After being reflected by the first high-reflection mirror, they return to the acousto-optic modulator along the original path. A third optical path transmission path is formed between the first optical path port of the acousto-optic modulator and the input port of the input fiber coupler. The acousto-optic modulator performs secondary diffraction coinciding processing on the zero-order light and the diffracted light. The coinciding zero-order light and the diffracted light are then transmitted to the input fiber coupler for coupling processing.

Description

Technical Field

[0001] This invention belongs to the field of optical technology, and in particular relates to a device and method for coinciding zero-order light and diffracted light based on an acousto-optic modulator. Background Technology

[0002] An acousto-optic modulator (AOM) is a device that uses the acousto-optic effect to change the properties of a light beam. The acousto-optic effect refers to the diffraction phenomenon of light caused by the change in the refractive index of a transparent medium when a sound wave passes through it. Therefore, acousto-optic modulators can be used to change the intensity, frequency, direction and other properties of light, and have the characteristics of fast response. They are widely used in laser physics, fiber optic communication, spectroscopy and other fields.

[0003] Acousto-optic modulators are based on the acousto-optic effect. Acoustic waves excite optical modes in a medium (usually a crystal), forming an acousto-optic diffraction grating. When a beam of light passes through this grating, diffraction occurs, thereby changing the properties of the light, i.e., forming 0th order light (light that has not been diffracted) and multiple diffraction orders (light that has been diffracted).

[0004] The overlap of 0th-order light and diffracted light based on acousto-optic modulators has wide applications in various scenarios. For example, in optical communication systems, multiple data streams can share the same optical fiber channel by modulating them to different frequencies, thereby enabling multiple frequency-shifted data streams to be transmitted through the same optical fiber at the same time, increasing the total data transmission capacity. At the same time, by beating the frequency of the frequency-shifted light and the unshifted light, the precise frequency of the frequency-shifted signal loaded by the acousto-optic modulator can be measured. In addition, during experiments, the polarization state or path of the light can be quickly switched by aligning the 0th-order light and the diffracted light using simple switching mechanisms (such as polarizing beam splitters, mirrors, or shutters), improving experimental efficiency.

[0005] However, under the current technology, conventional zero-order light and diffraction light overlap devices are unidirectional optical path arrangements. When the modulation frequency of the acousto-optic modulator is changed, the optical path arrangement parameters need to be readjusted, resulting in low overlap efficiency and limiting modulation accuracy and system performance. At the same time, the optical system design is relatively complex and the cost of use is high. Its performance is limited in specific application scenarios and it is difficult to meet diverse application needs. Summary of the Invention

[0006] The present invention provides a device and method for coinciding zero-order light and diffracted light based on an acousto-optic modulator, in order to solve the technical problems of conventional zero-order light and diffracted light coinciding devices having complex optical system design, inconvenient operation, and low coinciding efficiency.

[0007] To solve the above problems, the technical solution of the present invention is: a device for coinciding 0th order light and diffracted light based on an acousto-optic modulator, comprising: a light source, an output fiber optic coupler, an acousto-optic modulator, a first convex lens, a first high-reflection mirror, and an input fiber optic coupler.

[0008] The light source is connected to the input port of the output fiber coupler, and a first optical path transmission path is formed between the output port of the output fiber coupler and the first optical path port of the acousto-optic modulator. The output fiber coupler is used to output fundamental frequency light, and the light is transmitted to the acousto-optic modulator after preprocessing.

[0009] The second optical path port of the acousto-optic modulator and the first high-reflectivity mirror form a second optical path transmission path. The first convex lens is also provided between the acousto-optic modulator and the high-reflectivity mirror. The second optical path port of the acousto-optic modulator is coaxial with the central optical axis of the first convex lens and the first high-reflectivity mirror. The second optical path port of the acousto-optic modulator is located at the focal point of one side of the first convex lens. The first high-reflectivity mirror is located at the waist spot of the beam formed by the first convex lens. The first convex lens and the first high-reflectivity mirror are configured such that the 0th order light with an offset angle output by the acousto-optic modulator after one diffraction and the diffracted light are refracted by the first convex lens to form two parallel beams. The 0th order light and the diffracted light are then reflected by the first high-reflectivity mirror and can return to the acousto-optic modulator along the original path.

[0010] A third optical path transmission path is formed between the first optical path port of the acousto-optic modulator and the input port of the input fiber coupler. The zero-order light and the diffracted light after the second diffraction of the acousto-optic modulator are transmitted to the input fiber coupler, and the input fiber coupler performs coupling processing on the zero-order light and the diffracted light.

[0011] Preferably, the first optical transmission path is further provided with an isolator, which is connected to the output port of the output fiber coupler, and the isolator is used to limit the unidirectional transmission of optical signals.

[0012] Preferably, a polarizing beam splitter is provided in both the first optical path transmission path and the third optical path transmission path, and the central optical axis of the polarizing beam splitter is coaxial with the first optical path port of the acousto-optic modulator.

[0013] In the first optical path transmission path, the polarizing beam splitter is configured such that the light output from the isolator enters from the incident end on one side of the polarizing beam splitter, exits from the transmission end of the polarizing beam splitter along the first optical path transmission path, and is then transmitted to the first optical path port of the acousto-optic modulator.

[0014] In the third optical path transmission path, the polarization beam splitter is configured such that the light output from the first optical path port of the acousto-optic modulator enters from the incident end on the other side of the polarization beam splitter, exits from the reflecting end of the polarization beam splitter along the third optical path transmission path, and is then transmitted to the input fiber coupler.

[0015] Preferably, in the first optical path transmission path, a half-wave plate is further provided between the isolator and the polarizing beam splitter prism. The half-wave plate is used to adjust the polarization state of the light, so that the light output by the isolator can be emitted from the transmission end of the polarizing beam splitter prism.

[0016] In the second optical transmission path, a quarter-wave plate is also provided between the acousto-optic modulator and the first convex lens. The quarter-wave plate is used to adjust the polarization state of the light, so that the light reflected by the first high-reflection mirror can be emitted from the reflecting end of the polarizing beam splitter.

[0017] Preferably, a second high-reflection mirror and a third high-reflection mirror are sequentially provided between the isolator and the half-wave plate. The second high-reflection mirror and the third high-reflection mirror are tilted at 45° along the light path direction output by the isolator and are arranged facing each other. The second high-reflection mirror and the third high-reflection mirror are configured such that the light is adjusted to the first optical path port directly opposite the acousto-optic modulator after being reflected twice by the second high-reflection mirror and the third high-reflection mirror.

[0018] Preferably, a second convex lens and a concave lens are sequentially provided between the polarizing beam splitter and the first optical path port of the acousto-optic modulator. The central optical axes of the second convex lens and the concave lens are coaxial with the first optical path port of the acousto-optic modulator. By adjusting the relative position of the second convex lens and the concave lens, the waist spot area formed by the light is limited.

[0019] Preferably, a fourth high-reflection mirror is provided between the reflecting end of the polarizing beam splitter and the input fiber coupler. The fourth high-reflection mirror is tilted at 45° along the light path direction output from the reflecting end of the polarizing beam splitter. The fourth high-reflection mirror is configured such that the light output from the reflecting end of the polarizing beam splitter is adjusted to be directly opposite the input port of the input fiber coupler after being reflected by the fourth high-reflection mirror.

[0020] Preferably, the device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator further includes a power meter, which is connected to the output port of the input fiber optic coupler. The power meter is used to detect the coupling power between the 0th-order light and the diffracted light.

[0021] Preferably, the light source generating device is a single-frequency laser.

[0022] Based on the same concept, the present invention also provides a method for coinciding 0th-order light and diffracted light based on an acousto-optic modulator, applied to the above-described device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator, comprising the following steps:

[0023] S1: The light source outputs fundamental frequency light through the output fiber coupler. The light enters from the incident end on one side of the polarization beam splitter, exits from the transmission end of the polarization beam splitter, and is further transmitted to the acousto-optic modulator.

[0024] S2: The acousto-optic modulator performs a diffraction process on the light and outputs 0th-order light and diffracted light with an offset angle. After being refracted by the first convex lens, the 0th-order light and diffracted light form two parallel beams. After being reflected by the first high-reflection mirror, the 0th-order light and diffracted light return to the acousto-optic modulator along the original path.

[0025] S3: The acousto-optic modulator performs secondary diffraction processing on the returned light, and outputs the overlapping 0th order light and diffracted light in the opposite direction. The light enters from the incident end on the other side of the polarization beam splitter prism, exits from the reflection end of the polarization beam splitter prism, and is further transmitted to the input fiber coupler. The input fiber coupler performs coupling processing on the 0th order light and diffracted light.

[0026] Because the present invention adopts the above technical solution, it has the following advantages and positive effects compared with the prior art:

[0027] This invention provides a device and method for coinciding zero-order light and diffracted light based on an acousto-optic modulator. The device includes a first optical transmission path, a second optical transmission path, and a third optical transmission path. After the light beam is first transmitted to the acousto-optic modulator, zero-order light and diffracted light with beam deflection are generated. The zero-order light and diffracted light are refracted by a convex lens to form two parallel beams. The two parallel beams are then reflected back to the acousto-optic modulator to achieve coinciding, and are further transmitted to the input fiber optic coupler to achieve light coupling. In this invention, the second optical path transmission path is partially shared with the third optical path transmission path. While achieving the function of 0th-order light and diffracted light coinciding, the number of optical elements is reduced, simplifying the overall structural design. At the same time, based on the position setting of the convex lens and the high-reflection mirror, it is ensured that the 0th-order light and the diffracted light not only coincide precisely in direction, but also maintain the same spot size, which can effectively improve the efficiency and accuracy of subsequent light coupling. In addition, in this invention, the acousto-optic modulator is set at the focal position of the convex lens. When it is necessary to change the modulation frequency of the acousto-optic modulator, it is not necessary to readjust the relative position of the acousto-optic modulator and the convex lens, thus improving the ease of use. Attached Figure Description

[0028] Figure 1 A schematic diagram of the structure of the device for coinciding the 0th order light and the +1st order diffracted light of the acousto-optic modulator provided by the present invention;

[0029] Figure 2 A schematic diagram of the structure of the device for coinciding the 0th order light and the -1st order diffracted light of the acousto-optic modulator provided by the present invention;

[0030] Figure 3 Experimental results of 0th-order light and diffracted light provided by this invention.

[0031] Explanation of reference numerals in the attached figures: 1: Light source; 2: Output fiber optic coupler; 3: Isolator; 4: Second high-reflection mirror; 5: Third high-reflection mirror; 6: Half-wave plate; 7: Polarizing beam splitter prism; 8: Second convex lens; 9: Concave lens; 10: Acousto-optic modulator; 11: Quarter-wave plate; 12: First convex lens; 13: First high-reflection mirror; 14: Fourth high-reflection mirror; 15: Input fiber optic coupler; 16: Power meter. Detailed Implementation

[0032] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a device and method for coinciding 0th-order light and diffracted light based on an acousto-optic modulator. The advantages and features of the present invention will become clearer from the following description and claims.

[0033] First Embodiment

[0034] See Figure 1 and Figure 2 This embodiment provides a device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator, which is used to achieve efficient coinciding of 0th-order light and diffracted light.

[0035] Specifically, the main components of the device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator include a light source 1, an output fiber optic coupler 2, an acousto-optic modulator 10 with a driving frequency of 110MHz, a first convex lens 12, a first high-reflection mirror 13, and an input fiber optic coupler 15.

[0036] In this embodiment, the light source 1 and the input port of the output fiber coupler 2 can be connected by a fiber optic connector. The light source 1 is a single-frequency light source. In this embodiment, the light source generator is a 780nm single-frequency laser. The output port of the output fiber coupler 2 and the first optical path port of the acousto-optic modulator 10 form a first optical path transmission path. The output fiber coupler 2 is used to output fundamental frequency light. After preprocessing in the first optical path transmission path, the light is transmitted to the acousto-optic modulator 10.

[0037] A second optical path transmission path is formed between the second optical path port of the acousto-optic modulator 10 and the first high-reflection mirror 13. A first convex lens 12 is also provided in the second optical path transmission path between the acousto-optic modulator 10 and the first high-reflection mirror 13. In this embodiment, the focal length of the first convex lens 12 is 100mm. The second optical path port of the acousto-optic modulator 10 is coaxial with the central optical axis of the first convex lens 12 and the first high-reflection mirror 13. The second optical path port of the acousto-optic modulator 10 is located at the focal point of one side of the first convex lens 12. The first high-reflection mirror 13 is located at the waist spot of the beam formed by the first convex lens 12. At the same time, the first high-reflection mirror 13 is set at 0°, that is, the horizontal plane of the first high-reflection mirror 13 is perpendicular to the direction of the second optical path transmission path. The first convex lens 12 and the first high-reflection mirror 13 are configured such that when light enters the acousto-optic modulator 10 from the first optical path port, the acousto-optic modulator 10 can perform a diffraction process on the light by setting its own driving frequency, and then output 0th-order light and diffracted light (including +1st-order diffracted light and -1st-order diffracted light) with specific deflection angles from the second optical path port. After being refracted by the first convex lens 12, the 0th-order light and diffracted light form two parallel beams. Subsequently, the parallel 0th-order light and diffracted light are reflected by the first high-reflection mirror 13 and return along the original path. Returning to the second optical path port of the acousto-optic modulator 10, the 0th order light enters the second optical path port along the coaxial direction with the acousto-optic modulator 10, and the diffracted light still enters the second optical path port at a specific deflection angle. The 0th order light and the diffracted light converge at the second optical path port of the acousto-optic modulator 10. Then, the acousto-optic modulator 10 performs secondary diffraction processing on the light again, and the diffracted light is frequency-shifted, that is, the diffracted light moves back to maintain the same path as the 0th order light, so that the 0th order light and the diffracted light coincide. The first optical path port of the acousto-optic modulator 10 outputs the coincided light in the opposite direction.

[0038] A third optical path transmission path is formed between the first optical path port of the acousto-optic modulator 10 and the input port of the input fiber coupler 15. After the overlapping zero-order light and diffracted light are output through the first optical path port of the acousto-optic modulator 10, they are further transmitted to the input port of the input fiber coupler 15. The input fiber coupler 15 is used to couple the zero-order light and diffracted light, thereby coupling the light into the optical fiber.

[0039] In summary, this embodiment provides a device for coinciding zero-order light and diffracted light based on an acousto-optic modulator. The acousto-optic modulator 10 operates by causing the incident light to diffract once, forming separate zero-order light and diffracted light. Then, the refraction principle of the first convex lens 12 is used to convert the zero-order light and diffracted light with an offset angle difference into parallel beams. Subsequently, the reflection principle of the first high-reflection mirror 13 is used to return the zero-order light and diffracted light along their original paths. After secondary diffraction by the acousto-optic modulator 10, they achieve spatial coincidence. In this embodiment, the second optical path port of the acousto-optic modulator 10 is limited to the focal position on one side of the first convex lens 12. When the driving frequency of the acousto-optic modulator 10 changes, even if the offset angle between the 0th order light and the diffracted light changes accordingly, after parallel processing and reflection processing, the returned 0th order light and the diffracted light can still converge at the same focal position and perform subsequent secondary diffraction processing, which fully ensures the overlap accuracy of the 0th order light and the diffracted light. At the same time, the positions of the acousto-optic modulator 10, the first convex lens 12 and the first high-reflection mirror 13 are relatively fixed. When the driving frequency of the acousto-optic modulator 10 is adjusted, there is no need to adjust the positions of the three components accordingly, which greatly improves the work efficiency. Furthermore, in this embodiment, the first high-reflectivity mirror 13 is positioned at the waist spot of the beam formed by the first convex lens 12. The waist spot refers to the smallest cross-sectional area of ​​the beam during propagation, which is usually the part where the beam is most concentrated. Therefore, the position of the first high-reflectivity mirror 13 not only enables the 0th order light and diffracted light to return along the original path, but also ensures that the spot size of the returned beam does not change, so that the beam received by the acousto-optic modulator 10 has the best focusing characteristics, thereby improving the coupling efficiency and beam quality of the subsequent input fiber coupler 15.

[0040] Preferably, in one embodiment, an isolator 3 is further provided in the first optical transmission path. The isolator 3 is connected to the output port of the output fiber coupler 2. The isolator 3 is used to limit the optical signal to be transmitted in one direction only, to ensure that the optical signal is transmitted in the expected direction, to reduce unnecessary reflections, to enhance the overall stability and reliability of the system, to improve the efficiency of optical transmission, and at the same time, to prevent reflected light from returning to the light source 1 (such as a laser), so as to avoid damage to the laser performance or unstable operation.

[0041] Preferably, in one embodiment, a polarizing beam splitter prism 7 is provided in both the first and third optical transmission paths. The central optical axis of the polarizing beam splitter prism 7 is coaxially arranged with the first optical path port of the acousto-optic modulator 10. It is worth noting that in this embodiment, the first and third optical transmission paths partially overlap. This simplifies the structural design of the 0th-order light and diffracted light overlap device based on the acousto-optic modulator 10, while ensuring operational performance, and reduces the use of unnecessary optical components. The polarizing beam splitter prism 7 is a special optical element used to split linearly polarized light into two independent beams with different polarization directions according to the polarization state of the light. In this embodiment, the polarizing beam splitter prism 7 is used to split linearly polarized light into two independent beams with different polarization directions. Figure 1 and Figure 2 For example, if the left side of the polarizing beam splitter 7 is the incident end, then the right side of the polarizing beam splitter 7 is the transmission end, and the top side of the polarizing beam splitter 7 is the reflection end. If the right side of the polarizing beam splitter 7 is the incident end, then the left side of the polarizing beam splitter 7 is the transmission end, and the lower side of the polarizing beam splitter 7 is the reflection end.

[0042] Specifically, in the first optical path transmission path, the polarization beam splitter 7 is configured such that the light output from the isolator 3 enters from the incident end on the left side of the polarization beam splitter 7, exits from the transmission end on the right side of the polarization beam splitter 7 along the direction of the first optical path transmission path, and is then transmitted to the first optical path port of the acousto-optic modulator 10. The light entering from the incident end of the polarization beam splitter 7 and exiting from the transmission end is the desired beam obtained after polarization filtering.

[0043] Similarly, in the third optical path transmission path, the polarization beam splitter 7 is configured such that the light output from the first optical path port of the acousto-optic modulator 10 enters from the incident end on the right side of the polarization beam splitter 7, and along the third optical path transmission path, exits from the reflection end on the bottom side of the polarization beam splitter 7, and is then transmitted to the input fiber coupler 15. The light entering from the incident end of the polarization beam splitter 7 and exiting from the reflection end is the desired beam obtained after polarization filtering.

[0044] Furthermore, in the first optical path transmission path, a half-wave plate 6 is also provided between the isolator 3 and the polarizing beam splitter 7. When linearly polarized light passes through the half-wave plate 6, a phase delay of π (180°) will occur between the light wave component perpendicular to the optical axis of the wave plate and the light wave component parallel to the optical axis of the wave plate. This phase delay will cause the polarization direction of the incident light to change. That is, the half-wave plate 6 is used to adjust the polarization state of the light, thereby ensuring that the polarization direction of the incident light meets the requirements of the polarizing beam splitter 7 in the first optical path transmission path, and finally exits from the transmission end of the polarizing beam splitter 7 to obtain the desired beam.

[0045] Similarly, in the second optical transmission path, a quarter-wave plate 11 is also provided between the acousto-optic modulator 10 and the first convex lens 12. When linearly polarized light passes through the quarter-wave plate 11, a phase delay of π / 2 (90°) is generated between the light wave component perpendicular to the optical axis of the wave plate and the light wave component parallel to its optical axis. This phase delay will cause the polarization direction of the incident light to change. That is, the quarter-wave plate 11 is used to adjust the polarization state of the light, thereby ensuring that the polarization direction of the incident light meets the requirements of the polarization beam splitter 7 in the second optical transmission path, and finally exits from the reflecting end of the polarization beam splitter 7 to obtain the desired beam.

[0046] Preferably, in one embodiment, a second high-reflection mirror 4 and a third high-reflection mirror 5 are sequentially provided between the isolator 3 and the half-wave plate 6. In this embodiment, the second high-reflection mirror 4 and the third high-reflection mirror 5 are respectively tilted at 45° along the light path direction output by the isolator 3 and are arranged facing each other, so that the second high-reflection mirror 4 and the third high-reflection mirror 5 cooperate, and after the light is reflected twice by the second high-reflection mirror 4 and the third high-reflection mirror 5, it is adjusted to be directly opposite the first optical path port of the acousto-optic modulator 10. That is, in this embodiment, the second high-reflection mirror 4 and the third high-reflection mirror 5 cooperate to adjust the light path, so that the light output by the isolator 3 can be ensured to be directly transmitted to the first optical path port of the acousto-optic modulator 10.

[0047] Preferably, in one embodiment, a shaping lens group is further provided between the polarization beam splitter prism 7 and the first optical path port of the acousto-optic modulator 10. The shaping lens group includes a second convex lens 8 and a concave lens 9. The central optical axes of the second convex lens 8 and the concave lens 9 are coaxial with the first optical path port of the acousto-optic modulator 10. The shaping lens group is configured to limit the waist area of ​​the light beam by adjusting the relative position of the second convex lens 8 and the concave lens 9. Specifically, in this embodiment, the focal length of the second convex lens 8 is 200mm, the focal length of the concave lens 9 is -50mm, and the initial spot size of the fundamental frequency light output by the output fiber coupler 2 is 2mm. By adjusting the relative position of the second convex lens 8 and the concave lens 9, the initial spot can be reduced to one-quarter, that is, shaped into the optimal 500μm waist area required for acousto-optic modulation in this embodiment. This ensures that the beam is focused to the most compact state inside the acousto-optic modulator 10, optimizes the beam quality, and thus improves the generation quality and efficiency of the diffracted light.

[0048] Preferably, a fourth high-reflection mirror 14 is further provided between the reflecting end of the polarizing beam splitter 7 and the input fiber coupler 15. The fourth high-reflection mirror 14 is tilted at 45° along the light path direction output from the reflecting end of the polarizing beam splitter 7. The fourth high-reflection mirror 14 is configured such that the light output from the reflecting end of the polarizing beam splitter 7, after being reflected by the fourth high-reflection mirror 14, can be adjusted to be directly opposite the input port of the input fiber coupler 15. That is, in this embodiment, the fourth high-reflection mirror 14 is used to adjust the light path so that the light output from the reflecting end of the polarizing beam splitter 7 can be ensured to be directly transmitted to the input port of the input fiber coupler 15.

[0049] Preferably, the device for coinciding the 0th-order light and diffracted light based on the acousto-optic modulator further includes a power meter 16, which is connected to the output port of the input fiber optic coupler 15. The power meter 16 is used to detect the coupling power between the 0th-order light and the diffracted light. See also Figure 3Through experiments, the coupling efficiency of the 0th order light was measured with the diffraction frequency when the +1st / -1st order diffraction light was blocked, and the coupling efficiency of the +1st / -1st order diffraction light was measured with the diffraction frequency when the 0th order diffraction light was blocked. The experimental results show that the coupling efficiency of the two is similar and high with the frequency, both greater than 80%, which proves the efficient coupling effect between the 0th order light and the +1st / -1st order diffraction light.

[0050] Second Embodiment

[0051] See Figure 1 and Figure 2 Based on the same concept, the present invention also provides a method for coinciding 0th-order light and diffracted light based on an acousto-optic modulator, applied to the above-described device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator, comprising the following steps:

[0052] S1: Light source 1 outputs fundamental frequency light through output fiber coupler 2. After the light is transmitted unidirectionally through isolator 3, the light transmission path is adjusted by the second high-reflection mirror 4 and the third high-reflection mirror 5. After the polarization direction is adjusted by half-wave plate 6, the light enters from the incident end on the left side of polarizing beam splitter prism 7 and exits from the transmission end on the right side of polarizing beam splitter prism 7. Then, the second convex lens 8 and the concave lens 9 shape the light spot to the optimal light spot of acousto-optic modulator 10. Finally, the light is transmitted to the first optical path port of acousto-optic modulator 10.

[0053] S2: The acousto-optic modulator 10 performs a diffraction process on the light and outputs 0th-order light and diffracted light with an offset angle from its second optical path port. After being refracted by the first convex lens 12, the 0th-order light and diffracted light form two parallel beams. Then, the 0th-order light and diffracted light are reflected by the first high-reflection mirror 13 and return along the original path. After being refracted again by the first convex lens 12 and the polarization direction is adjusted by the quarter-wave plate 11, the 0th-order light and diffracted light re-converge at the second optical path port of the acousto-optic modulator 10.

[0054] S3: The acousto-optic modulator 10 performs secondary diffraction processing on the returned light, shifting the frequency of the diffracted light with the offset angle so that the 0th order light and the diffracted light maintain the same path and achieve overlap. Then, the acousto-optic modulator 10 outputs the overlapped 0th order light and diffracted light from its first optical path port. The light enters from the incident end on the right side of the polarization beam splitter 7 and exits from the reflection end on the bottom side of the polarization beam splitter 7. The light transmission path is adjusted by the fourth high-reflection mirror 14 and further transmitted to the input port of the input fiber coupler 15. The input fiber coupler 15 performs coupling processing on the 0th order light and the diffracted light. The power meter 16 detects the coupling power of the 0th order light and the diffracted light in real time.

[0055] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0056] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A device for coinciding zero-order light and diffracted light based on an acousto-optic modulator, characterized in that, include: Light source, output fiber optic coupler, acousto-optic modulator, first convex lens, first high-reflection mirror and input fiber optic coupler; The light source is connected to the input port of the output fiber coupler, and a first optical path transmission path is formed between the output port of the output fiber coupler and the first optical path port of the acousto-optic modulator. The output fiber coupler is used to output fundamental frequency light, and the light is transmitted to the acousto-optic modulator after preprocessing. The second optical path port of the acousto-optic modulator and the first high-reflectivity mirror form a second optical path transmission path. The first convex lens is also provided between the acousto-optic modulator and the high-reflectivity mirror. The second optical path port of the acousto-optic modulator is coaxial with the central optical axis of the first convex lens and the first high-reflectivity mirror. The second optical path port of the acousto-optic modulator is located at the focal point of one side of the first convex lens. The first high-reflectivity mirror is located at the waist spot of the beam formed by the first convex lens. The first convex lens and the first high-reflectivity mirror are configured such that the 0th order light with an offset angle output by the acousto-optic modulator after one diffraction and the diffracted light are refracted by the first convex lens to form two parallel beams. The 0th order light and the diffracted light are then reflected by the first high-reflectivity mirror and can return to the acousto-optic modulator along the original path. A third optical path transmission path is formed between the first optical path port of the acousto-optic modulator and the input port of the input fiber coupler. The zero-order light and the diffracted light after the second diffraction of the acousto-optic modulator are transmitted to the input fiber coupler, and the input fiber coupler performs coupling processing on the zero-order light and the diffracted light.

2. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 1, characterized in that, An isolator is also provided in the first optical transmission path. The isolator is connected to the output port of the output fiber coupler and is used to limit the unidirectional transmission of optical signals.

3. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 2, characterized in that, The first optical path transmission path and the third optical path transmission path are both provided with a polarizing beam splitter prism, and the central optical axis of the polarizing beam splitter prism is coaxial with the first optical path port of the acousto-optic modulator. In the first optical path transmission path, the polarizing beam splitter is configured such that the light output from the isolator enters from the incident end on one side of the polarizing beam splitter, exits from the transmission end of the polarizing beam splitter along the first optical path transmission path, and is then transmitted to the first optical path port of the acousto-optic modulator. In the third optical path transmission path, the polarization beam splitter is configured such that the light output from the first optical path port of the acousto-optic modulator enters from the incident end on the other side of the polarization beam splitter, exits from the reflecting end of the polarization beam splitter along the third optical path transmission path, and is then transmitted to the input fiber coupler.

4. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 3, characterized in that, In the first optical transmission path, a half-wave plate is also provided between the isolator and the polarizing beam splitter prism. The half-wave plate is used to adjust the polarization state of the light, so that the light output by the isolator can be emitted from the transmission end of the polarizing beam splitter prism. In the second optical transmission path, a quarter-wave plate is also provided between the acousto-optic modulator and the first convex lens. The quarter-wave plate is used to adjust the polarization state of the light, so that the light reflected by the first high-reflection mirror can be emitted from the reflecting end of the polarizing beam splitter.

5. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 4, characterized in that, A second high-reflection mirror and a third high-reflection mirror are sequentially provided between the isolator and the half-wave plate. The second high-reflection mirror and the third high-reflection mirror are tilted at 45° along the light path direction output by the isolator and are arranged facing each other. The second high-reflection mirror and the third high-reflection mirror are configured such that the light is adjusted to the first optical path port directly opposite the acousto-optic modulator after being reflected twice by the second high-reflection mirror and the third high-reflection mirror.

6. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 5, characterized in that, A second convex lens and a concave lens are sequentially provided between the polarizing beam splitter and the first optical path port of the acousto-optic modulator. The central optical axes of the second convex lens and the concave lens are coaxial with the first optical path port of the acousto-optic modulator. By adjusting the relative positions of the second convex lens and the concave lens, the waist spot area formed by the light is limited.

7. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 4, characterized in that, A fourth high-reflection mirror is also provided between the reflecting end of the polarizing beam splitter and the input fiber coupler. The fourth high-reflection mirror is tilted at 45° along the light path direction output from the reflecting end of the polarizing beam splitter. The fourth high-reflection mirror is configured such that the light output from the reflecting end of the polarizing beam splitter is adjusted to be directly opposite the input port of the input fiber coupler after being reflected by the fourth high-reflection mirror.

8. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 7, characterized in that, The device also includes a power meter connected to the output port of the input fiber optic coupler. The power meter is used to detect the coupling power between the 0th order light and the diffracted light.

9. The device for coinciding 0th-order light and diffracted light based on an acousto-optic modulator as described in claim 1, characterized in that, The light source generating device is a single-frequency laser.

10. A method for coinciding 0th-order light and diffracted light based on an acousto-optic modulator, characterized in that, The device for coinciding zero-order light and diffracted light based on an acousto-optic modulator as described in any one of claims 1-9 comprises the following steps: S1: The light source outputs fundamental frequency light through the output fiber coupler. The light enters from the incident end on one side of the polarization beam splitter, exits from the transmission end of the polarization beam splitter, and is further transmitted to the acousto-optic modulator. S2: The acousto-optic modulator performs a diffraction process on the light and outputs 0th-order light and diffracted light with an offset angle. After being refracted by the first convex lens, the 0th-order light and diffracted light form two parallel beams. After being reflected by the first high-reflection mirror, the 0th-order light and diffracted light return to the acousto-optic modulator along the original path. S3: The acousto-optic modulator performs secondary diffraction processing on the returned light, and outputs the overlapping 0th order light and diffracted light in the opposite direction. The light enters from the incident end on the other side of the polarization beam splitter prism, exits from the reflection end of the polarization beam splitter prism, and is further transmitted to the input fiber coupler. The input fiber coupler performs coupling processing on the 0th order light and diffracted light.

Images