Fiber collimator, acousto-optic modulator and method for correcting the first order diffraction light eccentricity of the acousto-optic modulator

Abstract

A fiber optic collimator, an acousto-optic modulator, and a method for correcting the first-order diffraction deviator of the acousto-optic modulator are provided. The fiber optic collimator includes a first sleeve, a first collimating lens, and a first capillary. The first capillary is disposed and encapsulated within the first sleeve, and is radially offset relative to the principal optical axis of the first collimating lens, such that the light beam emitted from the first optical fiber held by the first capillary, after passing through the first collimating lens, forms a Bragg angle with the normal to the light-transmitting surface of the acousto-optic crystal of the adapted acousto-optic modulator. The acousto-optic modulator includes a housing, an inlet glass tube, an outlet glass tube, an acousto-optic crystal, an acousto-optic transducer, an inlet fiber optic collimator, and an outlet fiber optic collimator. The inlet glass tube and the outlet glass tube are located on the same axis of the housing. The inlet fiber optic collimator is the aforementioned fiber optic collimator. In the method for correcting the first-order diffraction deviator of the acousto-optic modulator, the acousto-optic modulator is the aforementioned acousto-optic modulator.

Description

Technical Field

[0001] This disclosure relates to the field of lasers, and more specifically to an optical fiber collimator, an acousto-optic modulator, and a method for correcting the deviation of first-order diffraction light in an acousto-optic modulator. Background Technology

[0002] Acousto-optic modulators, as acousto-optic Q-switching devices, are widely used in fiber lasers and solid-state lasers due to their advantages such as small size, low insertion loss, high damage threshold, short switching time, and ability to be used for fiber coupling.

[0003] The propagation of ultrasound in an acousto-optic crystal causes a periodic change in the crystal's refractive index. This changing refractive index can be considered as a phase grating. Light incident on the acousto-optic crystal will undergo diffraction. For the acousto-optic modulator to operate, the ultrasound region within the acousto-optic crystal must form a certain angle with the incident light, i.e., the Bragg diffraction angle (also called the Bragg angle, which is the angle between the incident light and the normal to the light-transmitting surface 104a' of the acousto-optic crystal), so that the outgoing light consists only of the zero-order beam L0' and the first-order diffracted beam L1'. Figure 1 As shown, the first-order diffracted light L1' will be off-center relative to the zero-order light L0', meaning that the second collimating lens 107b' of the output fiber collimator 107' will receive the zero-order light L0' but will not receive the first-order diffracted light L1'. To receive the first-order diffracted light L1', as follows... Figure 2 As shown, this is generally achieved by simultaneously adjusting the optical fiber collimator 106' at the inlet (note that, in...). Figure 2 In this method, the optical fiber collimator 106' relative to the optical fiber glass tube 102' can be adjusted in position and / or angle, and the angle and / or position of the acousto-optic crystal 104' and the optical fiber collimator 107' can be adjusted. The disadvantage of this method is that the adjustment process is relatively cumbersome and takes a long time. Summary of the Invention

[0004] In view of the problems existing in the background art, one object of this disclosure is to provide an optical fiber collimator that can be installed after the light inlet glass tube of an acousto-optic modulator, so as to avoid the need for position and / or angle adjustment during the process of correcting the deviation of the first-order diffraction light of the acousto-optic modulator.

[0005] Another objective of this disclosure is to provide an acousto-optic modulator that avoids the cumbersome problem of simultaneously adjusting the angles and / or positions of the collimator at the light inlet, the acousto-optic crystal, and the collimator at the light outlet during the process of correcting the deviation of the first-order diffraction light of the acousto-optic modulator.

[0006] Another object of this disclosure is to provide a method for correcting the first-order diffraction deviance of an acousto-optic modulator, which reduces the difficulty of optical path adjustment for the first-order diffraction deviance of the acousto-optic modulator.

[0007] Therefore, an optical fiber collimator is provided, comprising a first sleeve, a first collimating lens, and a first capillary. The first sleeve includes a first tube wall and a first inner cavity enclosed by the first tube wall. The first capillary is disposed and encapsulated in the first inner cavity of the first sleeve, and the first capillary is located at a first end of the first sleeve, serving to hold an inserted first optical fiber. The first collimating lens is disposed and encapsulated in the first inner cavity of the first sleeve, and the first collimating lens is located at a second end of the first sleeve. The end face of the first capillary mates with the opposite side of the first collimating lens. The first capillary is radially offset relative to the principal optical axis of the first collimating lens, such that the light beam emitted from the first optical fiber held by the first capillary, after passing through the first collimating lens, forms a Bragg angle with the normal of the light-transmitting surface of the acousto-optic crystal of the adapted acousto-optic modulator.

[0008] An acousto-optic modulator is provided, comprising a housing, an inlet glass tube, an outlet glass tube, an acousto-optic crystal, an acousto-optic transducer, an inlet fiber optic collimator, and an outlet fiber optic collimator. The housing has opposite first and second ends. The inlet glass tube is located at the first end of the housing, and the outlet glass tube is located at the second end of the housing. The inlet fiber optic collimator is placed within the inlet glass tube. The outlet fiber optic collimator is placed within the outlet glass tube. The acousto-optic crystal is located within the housing and between the first and second ends of the housing. The acousto-optic transducer is disposed on the side of the acousto-optic crystal where a first direction opposite to the first and second ends of the housing intersects with a second direction. The acousto-optic transducer is connected to a driving power supply. The outlet fiber optic collimator is a single-fiber collimator. The inlet and outlet glass tubes are located on the same axis as the housing. The inlet fiber optic collimator is the aforementioned fiber optic collimator.

[0009] A method is provided for correcting the decentering of first-order diffraction light in an acousto-optic modulator, wherein the acousto-optic modulator is the aforementioned acousto-optic modulator, and the method includes the following steps:

[0010] S1, turn on the laser source, and move the optical inlet collimator holding a first optical fiber to the optical inlet glass tube located at the first end of the housing of the acousto-optic modulator, so that the first optical fiber transmits the beam to the acousto-optic crystal.

[0011] S2, move the optical fiber collimator holding a second optical fiber to the optical fiber outlet glass tube located at the second end of the housing of the acousto-optic modulator;

[0012] S3, turn on the drive power supply of the acousto-optic modulator connected to the acousto-optic transducer so that the incident light entering the acousto-optic crystal from the first optical fiber input generates first-order diffracted light. Adjust only the position and / or angle of the acousto-optic crystal so that the first-order diffracted light emitted from the acousto-optic crystal is transmitted to the center of the second collimating lens of the optical fiber collimator at the output port.

[0013] The beneficial effects of this disclosure are as follows: In the fiber collimator of this disclosure, due to the radial offset of the first capillary relative to the principal optical axis of the first collimating lens, the light beam emitted from the first optical fiber held by the first capillary, after passing through the first collimating lens, produces a horizontal deflection angle (refer to...). Figure 3 (The horizontal direction is the D1 direction). This horizontal deflection avoids the need to adjust the angle and / or position of the inlet collimator (i.e., the fiber optic collimator of this disclosure) simultaneously with the adjustment of the acousto-optic crystal when the fiber optic collimator is installed in the inlet glass tube of the acousto-optic modulator described later, so that the outlet fiber optic collimator located in the outlet glass tube can receive first-order diffracted light. In other words, in the acousto-optic modulator described later, after the fiber optic collimator is placed in the inlet glass tube, the fiber optic collimator is fixed relative to the inlet glass tube without the need for angle and / or position adjustment.

[0014] In the acousto-optic modulator disclosed herein, the inlet fiber optic collimator is the aforementioned fiber optic collimator. Due to the radial offset of the first capillary relative to the principal optical axis of the first collimating lens, the beam emitted by the fiber optic collimator generates a horizontal deflection angle. Only the angle and / or position of the acousto-optic crystal needs to be adjusted to correct the first-order diffraction of the acousto-optic modulator, avoiding the cumbersome adjustment problem caused by the need to simultaneously adjust the angles and / or positions of the inlet fiber optic collimator, the acousto-optic crystal, and the outlet fiber optic collimator in traditional fiber optic collimators. In other words, in the acousto-optic modulator, the inlet fiber optic collimator is placed after the inlet glass tube and fixed relative to the inlet glass tube without requiring angle and / or position adjustments.

[0015] The method disclosed herein for correcting the first-order diffraction eccentricity of an acousto-optic modulator only requires adjusting the angle and / or position of the acousto-optic crystal so that the incident light transmitted to the acousto-optic crystal and the outgoing light output from the acousto-optic crystal are on the same axis. This method can correct the first-order diffraction eccentricity of the acousto-optic modulator, thereby reducing the difficulty of adjusting the optical path for the first-order diffraction eccentricity of the acousto-optic modulator. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the principle that the first-order diffracted light of the acousto-optic modulator will be eccentric relative to the zero-order light, based on the background technology.

[0017] Figure 2 This is a schematic diagram based on the background technology, showing that after adjusting the angles and / or positions of the inlet optical fiber collimator, the acousto-optic crystal, and the outlet optical fiber collimator, the first-order diffraction light of the acousto-optic modulator is no longer off-center.

[0018] Figure 3 This is a schematic diagram of the principle that, after adjusting the angle and / or position of the acousto-optic crystal, the first-order diffraction light of the acousto-optic modulator is no longer off-center, according to the present disclosure.

[0019] Figure 4 yes Figure 3 A cross-sectional view of the optical fiber collimator at the inlet.

[0020] The reference numerals in the attached figures are explained as follows:

[0021] 100' Fiber Optic Collimator 12 First Collimating Lens

[0022] 11' First sleeve 121 Main optical axis

[0023] 12' First collimating lens 13 First capillary

[0024] 13' First capillary 200 First optical fiber

[0025] 1000' Acousto-optic Modulator

[0026] 101' housing 101 housing

[0027] D1' First direction 101a First end

[0028] D2' Second Direction 101b Second End

[0029] 102' Inlet glass tube D1 First direction

[0030] 103' light outlet glass tube D2 second direction

[0031] 104' Acousto-optic crystal, 102 inlet glass tube

[0032] 104a' light-transmitting surface 103 light-emitting port glass tube

[0033] 105' Acousto-optic transducer, 104 acousto-optic crystal

[0034] 106' Inlet Fiber Collimator 104a Light Transmitter

[0035] 107' optical fiber collimator with output port; 105 acousto-optic transducer

[0036] 107a' Second Sleeve 106 Inlet Fiber Optic Collimator

[0037] 107b' Second Collimating Lens 107 Output Port Fiber Optic Collimator

[0038] 107c' second capillary tube 107a second sleeve

[0039] L0' Zero-order light r1 Second tube wall

[0040] L1' First-order diffraction light r2 Second inner cavity

[0041] 100 fiber optic collimator P1 first end

[0042] 11 First sleeve P2 Second end

[0043] 11a First tube wall 107b Second collimating lens

[0044] 11b First inner cavity 107c Second capillary

[0045] S1 First End L0 Zero-Level Light

[0046] S2 second end L1 first-order diffraction light Detailed Implementation

[0047] The accompanying drawings illustrate embodiments of this disclosure, and it will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0048] [Fiber Optic Collimator]

[0049] Reference Figure 4 The fiber optic collimator 100 according to this disclosure includes a first sleeve 11, a first collimating lens 12, and a first capillary tube 13. The first sleeve 11 includes a first tube wall 11a and a first inner cavity 11b enclosed by the first tube wall 11a. The first capillary tube 13 is disposed and encapsulated within the first inner cavity 11b of the first sleeve 11, and is located at the first end S1 of the first sleeve 11. The first capillary tube 13 is used to hold an inserted first optical fiber 200. The first collimating lens 12 is disposed and encapsulated within the first inner cavity 11b of the first sleeve 11, and is located at the second end S2 of the first sleeve 11. The end face of the first capillary tube 13 mates with the end face of the first collimating lens 12 on the opposite side. The first capillary tube 13 is radially offset relative to the principal optical axis 121 of the first collimating lens 12, such that the light beam emitted from the first optical fiber 200 held by the first capillary tube 13, after passing through the first collimating lens 12, forms a Bragg angle with the normal of the light transmission surface 104a of the acousto-optic crystal 104 of the adapted acousto-optic modulator 1000 (that is, the angle between the light beam passing through the first collimating lens 12 and entering the light transmission surface 104a of the acousto-optic crystal 104 and the normal of the light transmission surface 104a).

[0050] In the fiber optic collimator 100 disclosed herein, due to the radial offset of the first capillary 13 relative to the principal optical axis 121 of the first collimating lens 12, the light beam emitted from the first optical fiber 200 held by the first capillary 13, after passing through the first collimating lens 12, produces a horizontal deflection angle (see reference). Figure 3(The horizontal direction is the D1 direction). This horizontal deflection avoids the need to adjust the angle and / or position of the inlet collimator 106 (i.e., the fiber optic collimator 100 of this disclosure) simultaneously with the adjustment of the position of the fiber optic collimator 100 in the inlet glass tube 102 of the acousto-optic modulator 100 (described later) in conjunction with the adjustment of the acousto-optic crystal 104, so that the outlet fiber optic collimator 107 located in the outlet glass tube 103 can receive the first-order diffracted light L1. That is to say, in the acousto-optic modulator 100 (described later), after the fiber optic collimator 100 is placed in the inlet glass tube 102, the fiber optic collimator 100 is fixed relative to the inlet glass tube 102 without the need for angle and / or position adjustment.

[0051] The first capillary tube 13 consists of multiple tubes. (Refer to...) Figure 4 There are two first capillary tubes 13. The two first capillary tubes 13 are symmetrical with respect to the principal optical axis 121 of the first collimating lens 12. The two first capillary tubes 13 can be arranged vertically or horizontally in the meridional plane of the fiber optic collimator 100. Either of the two first capillary tubes 13 can be inserted into the first optical fiber 200 during use.

[0052] The first collimating lens 12 is either a conventional lens (C-lens) or a self-focusing lens (Grin-lens).

[0053] The first optical fiber 200 is a single-mode or multimode optical fiber. Alternatively, the first optical fiber 200 is an optical fiber with a bending loss of less than 0.1 dB / km.

[0054] [Acousto-optic modulator]

[0055] Reference Figure 3The acousto-optic modulator 1000 according to this disclosure includes a housing 101, an inlet glass tube 102, an outlet glass tube 103, an acousto-optic crystal 104, an acousto-optic transducer 105, an inlet fiber optic collimator 106, and an outlet fiber optic collimator 107. The housing 101 has opposite first ends 101a and second ends 101b. The inlet glass tube 102 is disposed at the first end 101a of the housing 101, and the outlet glass tube 103 is disposed at the second end 101b of the housing 101. The inlet fiber optic collimator 106 is placed within the inlet glass tube 102. The outlet fiber optic collimator 107 is placed within the outlet glass tube 103. The acousto-optic crystal 104 is located within the housing 101 and between the first end 101a and the second end 101b of the housing 101. An acousto-optic transducer 105 is disposed on the side of the acousto-optic crystal 104 where a first direction D1 intersects a second direction D2 opposite to the first end 101a and the second end 101b of the housing 101. The acousto-optic transducer 105 is used to connect to a driving power supply. The output fiber optic collimator 107 is a single-fiber collimator. The input glass tube 102 and the output glass tube 103 are located on the same axis of the housing 101. The input fiber optic collimator 106 is the aforementioned fiber optic collimator 100.

[0056] In the acousto-optic modulator 1000 of this disclosure, the inlet fiber optic collimator 106 is the aforementioned fiber optic collimator 100. Because the first capillary 13 is radially offset relative to the principal optical axis 121 of the first collimating lens 12, the beam emitted by the fiber optic collimator 100 exhibits a horizontal deflection. Only the angle and / or position of the acousto-optic crystal 104 needs to be adjusted to correct the eccentricity of the first-order diffracted light L1 of the acousto-optic modulator. This avoids the cumbersome adjustment problem caused by the traditional fiber optic collimator 1000' requiring simultaneous adjustment of the angles and / or positions of the inlet fiber optic collimator 106', the acousto-optic crystal 104', and the outlet fiber optic collimator 107'. In other words, in the acousto-optic modulator 1000, after the inlet fiber optic collimator 106 is placed behind the inlet glass tube 102, the inlet fiber optic collimator 106 is fixed relative to the inlet glass tube 102 without requiring angle and / or position adjustments.

[0057] The inlet glass tube 102 and the outlet glass tube 103 are located on the same axis of the housing 101, so that the inlet fiber collimator 106 located at the first end 101a and the outlet fiber collimator 107 located at the first end 101b are also located on the same axis. This facilitates the positioning and correction of the installation positions of the inlet fiber collimator 106 and the outlet fiber collimator 107, reduces the coupling difficulty of the outlet fiber collimator 107, and improves production efficiency. At the same time, only the angle and / or position of the acousto-optic crystal 104 needs to be adjusted so that the incident light transmitted to the acousto-optic crystal 104 and the outgoing light output from the acousto-optic crystal 104 are on the same axis. This can correct the eccentricity of the first-order diffraction light L1 of the acousto-optic modulator 1000. This avoids the cumbersome adjustment problem caused by the traditional fiber collimator 1000' which requires simultaneous adjustment of the angle and / or position of the inlet fiber collimator 106', the acousto-optic crystal 104', and the outlet fiber collimator 107'.

[0058] The optical fiber collimator 107 includes a second sleeve 107a, a second collimating lens 107b, and a single second capillary tube 107c. The second sleeve 107a includes a second tube wall r1 and a second inner cavity r2 formed by the second tube wall r1. The single second capillary tube 107c is disposed and encapsulated in the second inner cavity r2 of the second sleeve 107a, and the second capillary tube 107c is located at the first end P1 of the second sleeve 107a. The second capillary tube 107c is used to clamp the inserted second optical fiber. (Not shown); The second collimating lens 107b is disposed and encapsulated in the second inner cavity r2 of the second sleeve 107a, and the second collimating lens 107b is located at the second end P2 of the second sleeve 107a, the second end P2 of the second sleeve 107a is opposite to the second end S2 of the first sleeve 11; the end face of the second capillary 107c is matched with the side opposite to the second collimating lens 107b; the axis of the single second capillary 107c coincides with the principal optical axis of the second collimating lens 107b.

[0059] [A method for correcting the acousto-optic diffraction asymmetry of first-order diffracted light]

[0060] Reference Figure 3 The method for correcting the first-order diffraction decenter of an acousto-optic modulator 1000 according to this disclosure includes the following steps:

[0061] S1, turn on the laser source (not shown), and move the inlet fiber collimator 106, which holds a first fiber 200, to the inlet glass tube 102 located at the first end 101a of the housing 101 of the acousto-optic modulator 1000, so that the first fiber 200 transmits a beam to the acousto-optic crystal 104.

[0062] S2, the optical fiber collimator 107 holding a second optical fiber is moved to the optical fiber outlet glass tube 103 located at the second end 101b of the housing 101 of the acousto-optic modulator 1000.

[0063] S3, turn on the drive power supply of the acousto-optic modulator 1000 connected to the acousto-optic transducer 105, so that the incident light entering the acousto-optic crystal 104 input from the first optical fiber 200 generates first-order diffracted light L1. Adjust only the position and / or angle of the acousto-optic crystal 104 so that the first-order diffracted light L1 emitted from the acousto-optic crystal 104 is transmitted to the center of the second collimating lens 107b of the optical fiber collimator 107 at the light outlet.

[0064] The method disclosed herein for correcting the first-order diffraction light eccentricity of an acousto-optic modulator only requires adjusting the angle and / or position of the acousto-optic crystal 104 so that the incident light transmitted to the acousto-optic crystal 104 and the outgoing light output from the acousto-optic crystal 104 are on the same axis. This can correct the eccentricity of the first-order diffraction light L1 of the acousto-optic modulator 1000, reducing the difficulty of adjusting the optical path for the eccentricity of the first-order diffraction light L1 of the acousto-optic modulator.

[0065] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. An acousto-optic modulator, comprising a housing (101), an inlet glass tube (102), an outlet glass tube (103), an acousto-optic crystal (104), an acousto-optic transducer (105), an inlet fiber optic collimator (106), and an outlet fiber optic collimator (107). The housing (101) has opposite first end (101a) and second end (101b), with an inlet glass tube (102) located at the first end (101a) of the housing (101) and an outlet glass tube (103) located at the second end (101b) of the housing (101). The optical fiber collimator (106) is used to be placed in the optical fiber glass tube (102); The optical fiber collimator (107) at the output port is used to be placed in the glass tube (103) at the output port; The acousto-optic crystal (104) is located inside the housing (101) and between the first end (101a) and the second end (101b) of the housing (101); The acousto-optic transducer (105) is disposed on the side of the acousto-optic crystal (104) where the first direction (D1) intersects the second direction (D2) opposite to the first end (101a) and the second end (101b) of the housing (101). The acousto-optic transducer (105) is used to connect to the driving power supply. The optical fiber collimator (107) at the output port is a single-fiber collimator; Its features are, The light inlet glass tube (102) and the light outlet glass tube (103) are located on the same axis of the housing (101); The optical fiber collimator (106) includes a first sleeve (11), a first collimating lens (12), and a first capillary (13). The first sleeve (11) includes a first tube wall (11a) and a first inner cavity (11b) formed by the first tube wall (11a). The first capillary (13) is disposed and encapsulated in the first inner cavity (11b) of the first sleeve (11), and the first capillary (13) is located at the first end (S1) of the first sleeve (11). The first capillary (13) is used to hold the inserted first optical fiber (200). The first collimating lens (12) is disposed and encapsulated in the first inner cavity (11b) of the first sleeve (11), and the first collimating lens (12) is located at the second end (S2) of the first sleeve (11). The end face of the first capillary (13) is matched with the end face of the first collimating lens (12) on the opposite side; The first capillary (13) is radially offset relative to the principal optical axis (121) of the first collimating lens (12), such that the light beam emitted from the first optical fiber (200) held by the first capillary (13) passes through the first collimating lens (12) and forms a Bragg angle with the normal of the light transmission surface (104a) of the acousto-optic crystal (104) of the adapted acousto-optic modulator (1000); In this process, only the position or angle of the acousto-optic crystal (104) is adjusted so that the first-order diffracted light (L1) emitted from the acousto-optic crystal (104) is transmitted to the center of the second collimating lens (107b) of the optical fiber collimator (107) at the output port, so that the second collimating lens (107b) receives the first-order diffracted light (L1) at the same time as receiving the zero-order light (L0) emitted from the acousto-optic crystal (104).

2. The acousto-optic modulator according to claim 1, characterized in that, The optical fiber collimator (107) at the output port includes a second sleeve (107a), a second collimating lens (107b), and a single second capillary tube (107c). The second sleeve (107a) includes a second tube wall (r1) and a second inner cavity (r2) enclosed by the second tube wall (r1); A single second capillary tube (107c) is disposed and encapsulated in the second inner cavity (r2) of the second sleeve (107a), and the second capillary tube (107c) is located at the first end (P1) of the second sleeve (107a). The second capillary tube (107c) is used to clamp the inserted second optical fiber. The second collimating lens (107b) is disposed and encapsulated in the second inner cavity (r2) of the second sleeve (107a), and the second collimating lens (107b) is located at the second end (P2) of the second sleeve (107a), which is opposite to the second end (S2) of the first sleeve (11). The end face of the second capillary (107c) is matched with the end face of the second collimating lens (107b) on the opposite side; The axis of the single second capillary (107c) coincides with the principal optical axis of the second collimating lens (107b).

3. The acousto-optic modulator according to claim 1, characterized in that, There are multiple first capillaries (13).

4. The acousto-optic modulator according to claim 3, characterized in that, There are two first capillaries (13); The two first capillaries (13) are symmetrical about the principal optical axis (121) of the first collimating lens (12).

5. The acousto-optic modulator according to claim 1, characterized in that, The first collimating lens (12) is a conventional lens (C-lens) or a self-focusing lens (Grin-lens).

6. The acousto-optic modulator according to claim 1, characterized in that, The first optical fiber (200) is a single-mode or multimode optical fiber.

7. The acousto-optic modulator according to claim 1, characterized in that, The first optical fiber (200) is an optical fiber with a bending loss of less than 0.1 dB / km.

8. A method for correcting the decentricity of first-order diffraction light in an acousto-optic modulator, characterized in that, The acousto-optic modulator (1000) is the acousto-optic modulator (1000) according to any one of claims 1-7, and the method includes the steps of: S1, turn on the laser source and move the inlet fiber collimator (106) that holds a first fiber (200) to the inlet glass tube (102) at the first end (101a) of the housing (101) of the acousto-optic modulator (1000) so that the first fiber (200) transmits the light beam to the acousto-optic crystal (104). S2, the optical fiber collimator (107) holding a second optical fiber is moved to the optical fiber outlet glass tube (103) located at the second end (101b) of the housing (101) of the acousto-optic modulator (1000); S3, turn on the drive power supply of the acousto-optic modulator (1000) connected to the acousto-optic transducer (105) so that the incident light entering the acousto-optic crystal (104) from the first optical fiber (200) generates first-order diffracted light (L1). Adjust only the position or angle of the acousto-optic crystal (104) so ​​that the first-order diffracted light (L1) emitted from the acousto-optic crystal (104) is transmitted to the center of the second collimating lens (107b) of the optical fiber collimator (107) at the output port so that the second collimating lens (107b) receives the first-order diffracted light (L1) at the same time as receiving the zero-order light (L0) emitted from the acousto-optic crystal (104).

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