CN217932320U - Ultrafast laser fiber modulation frequency selector - Google Patents

Abstract

The utility model discloses an ultrafast laser fiber modulation frequency selector, including pulse laser light source link, first collimator, acousto-optic switch, second collimator, third collimator and fourth collimator, pulse laser light source passes through optic fibre and is connected with the input of first collimator, the laser of first collimator incides acousto-optic switch and by get into the input of second collimator after the acousto-optic switch modulation, the output of second collimator passes through optic fibre and is connected with the input of third collimator, the laser of third collimator incides acousto-optic switch and by get into the input of fourth collimator after the acousto-optic switch modulation, the output of fourth collimator is connected with the laser output of modulation frequency selector. The utility model discloses the scheme has realized the high on-off ratio of modulation frequency selector.

Description

Ultrafast laser fiber modulation frequency selector

Technical Field

The utility model relates to the field of laser technology, especially, relate to an ultrafast laser fiber modulation frequency selector.

Background

The optical modulation technology is an extremely important technology in the fields of optical communication, optical fiber sensing, laser and the like, and a modulator (modulation frequency selector) can change optical wave parameters along with the change of an external signal, wherein the optical wave parameters comprise intensity (amplitude), phase, frequency, polarization, wavelength and the like of optical waves.

In the field of ultrafast laser application, the optical modulation technology is also widely applied, wherein one modulator modulates and selects the frequency of the pulse frequency of the light wave through the function of a fast optical switch, so that the pulse frequency of the laser can be reduced. Therefore, the pulse laser light source with higher cost performance can be applied to more low-pulse scenes. Pulsed laser refers to laser light that is not divided into continuous waves so that some pulses of a certain duration occur in the optical power, repeating them, avoiding the problem of temperature rise caused by continuous laser light. For example, in laser ablation, if the workpiece is heated for a short period of time, a small amount of material on the surface of the workpiece vaporizes and excess laser generated heat is conducted to other portions of the workpiece so that the laser ablation site does not reach an excessive temperature.

The common laser modulator is modulated by an acousto-optic modulator, and the working principle of the acousto-optic modulator is as follows: when an ultrasonic wave passes through a certain homogeneous medium (acousto-optic crystal), the medium material is deformed under the action of an external force, and molecules change due to the interaction force to generate relative displacement, so that the fluctuation or periodic change of the internal density of the medium is caused, the refractive index is large at a place with high density, and the refractive index is small at a place with low density, namely the refractive index of the medium is changed periodically.

The principle of acousto-optic modulators can be referred to in hundred degrees encyclopedia. The operation principle of the bragg-type modulator is shown in fig. 1. In the case of the rf power Ps versus diffraction efficiency η as shown in fig. 2, bragg diffraction must be such that the incident beam is incident at a bragg angle θ b, while satisfactory results are obtained when the diffracted beam is received in a direction symmetrical with respect to the mechanical wavefront.

Therefore, the high-frequency pulse incident through the Bragg angle receives the diffracted light at the Bragg diffraction angle exit end, and the desired low-frequency pulse signal can be obtained at the Bragg diffraction exit end by quickly controlling the radio-frequency electric signal. The prior art still has the problem that the on-off ratio is not high enough when laser pulse modulation is carried out, so that the problems that low-frequency laser pulse emitted during pulse frequency selection still has high-frequency pulse which is partially not completely eliminated, and the pulse frequency control is not thorough and stable enough are caused.

The prior art proposes a technical scheme of an acousto-optic modulator with a high on-off ratio, such as chinese patent application, application number: 201810316410.5, application name: a high-performance optical fiber coupling acousto-optic modulator. In this patent application, there is disclosed: the utility model provides a high performance's fiber coupling acoustic optical modulator, it includes input extinction structure, output extinction structure, the input end speculum, the output end speculum, the casing that has the holding chamber and the input fiber who sets up in the casing holding intracavity in proper order, input collimating lens, the acousto-optic crystal, output collimating lens and output fiber, input reflecting mirror and output reflecting mirror symmetry respectively set up the both sides at the acousto-optic crystal, input extinction structure is relative with the input end speculum and is used for receiving the light that the input reflecting mirror reflects, output extinction structure is relative with the output reflecting mirror and is used for receiving the light that the output reflecting mirror reflects, the acousto-optic crystal is connected and is controlled by radio frequency drive module electricity with the radio frequency drive module, the utility model discloses not only have high on-off ratio for it has better Q-regulating effect in being applied to the laser instrument, but also have high reliability concurrently, temperature tolerance and have high damage threshold, make can be fit for using in high-power laser. This patent has realized improving the on-off ratio of device through setting up speculum and extinction structure, and the structure is complicated, and is with high costs.

SUMMERY OF THE UTILITY MODEL

Therefore, an ultrafast laser fiber modulation frequency selector with a high switching ratio is needed to be provided, and the problem that when the conventional fiber modulation frequency selector in ultrafast laser is used for selecting a frequency from a high-frequency pulse to a low-frequency pulse, part of high-frequency pulses exist in the low-frequency laser pulse, and the pulse frequency is not completely controlled and is not stable enough is solved.

In order to realize the above object, the utility model provides an ultrafast laser fiber modulation frequency selector, including pulse laser light source link, first collimator, acousto-optic switch, second collimator, third collimator and fourth collimator, pulse laser light source link is used for being connected with pulse laser light source, pulse laser light source link passes through optic fibre and is connected with the input of first collimator, the laser incidence of first collimator acousto-optic switch and by get into the input of second collimator after the acousto-optic switch modulation, the output of second collimator passes through optic fibre and is connected with the input of third collimator, the laser incidence of third collimator acousto-optic switch and by get into the input of fourth collimator after the acousto-optic switch modulation, the output and the laser output end of modulation frequency selector of fourth collimator are connected.

The optical path switching device further comprises a first optical path switching device, a public input end of the first optical path switching device is connected with an output end of the second collimator through an optical fiber, an output end of the first optical path switching device is connected with an input end of the third collimator, and the other output end of the first optical path switching device is connected with a laser output end of the modulation frequency selector through an optical fiber.

The optical path switching device further comprises a second optical path switching device, one input end of the second optical path switching device is connected with the output end of the fourth collimator, the other input end of the second optical path switching device is connected with the other output end of the first optical path switching device through an optical fiber, and the common output end of the second optical path switching device is connected with the laser output end of the modulation frequency selector.

And the output end of the fourth collimator is connected with the laser output end of the modulation frequency selector after passing through the laser amplifier.

Further, still include control chip, control chip with the first light path switch is connected, control chip is used for controlling the switching of first light path switch.

Further, the control chip is configured to automatically control the first light path switcher to switch to a common input end of the first light path switcher to be connected with an output end of the first light path switcher after obtaining that the pulse parameter is greater than the preset value.

Further, the pulse parameter is a pulse frequency.

Further, the control chip is a single chip microcomputer.

Further, the pulse laser light source is a picosecond laser light source.

Furthermore, the acousto-optic switch comprises an acousto-optic crystal, a transducer and a driving circuit.

Different from the prior art, according to the technical scheme, the laser pulse is modulated for the first time through the acousto-optic switch through the first collimator and the second collimator, the modulated laser pulse passes through the third collimator and the fourth collimator, the modulated laser pulse is modulated for the second time through the acousto-optic switch and then is output, after twice modulation, the frequency of the laser pulse output by the modulation frequency selector is stable, and the high on-off ratio of the modulation frequency selector is realized. In particular, the present invention has significant advantages and improvements in ultrafast laser applications.

Drawings

FIG. 1 is a schematic diagram of a Bragg-type acousto-optic modulator according to the background art;

FIG. 2 is a diagram illustrating the characteristic curves of an acousto-optic modulator according to the prior art;

fig. 3 is a schematic structural diagram of an embodiment of the ultrafast laser fiber modulation frequency selector according to the embodiment;

fig. 4 is a schematic diagram comparing the present invention with the prior art when modulating and selecting frequency;

FIG. 5 is a schematic diagram of an embodiment of a ultrafast laser fiber modulated frequency selector including a light source;

fig. 6 is a schematic structural diagram of another embodiment of the ultrafast laser fiber modulation frequency selector according to the embodiment;

fig. 7 is a schematic structural diagram of another embodiment of the ultrafast laser fiber modulation frequency selector according to the embodiment;

FIG. 8 is a schematic structural diagram of a further embodiment of an ultrafast laser fiber modulation frequency selector according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of another embodiment of the ultrafast laser fiber modulation frequency selector according to the embodiment.

Description of the reference numerals:

1. a modulation frequency selector;

11. a pulsed laser light source;

12. a first collimator;

13. an acousto-optic switch;

14. a second collimator;

15. a third collimator;

16. a fourth collimator;

17. a first optical path switcher;

18. an optical fiber combiner;

19. a second optical path switcher;

20. and a laser amplifier.

Detailed Description

To explain technical contents, structural features, and objects and effects of the technical solutions in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or related to other embodiments specifically defined. In principle, in the present application, the technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution as long as there is no technical contradiction or conflict.

Unless defined otherwise, technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the use of relational terms herein is intended only to describe particular embodiments and is not intended to limit the present application.

In the description of the present application, the term "and/or" is a expression for describing a logical relationship between objects, meaning that three relationships may exist, for example a and/or B, meaning: there are three cases of A, B, and both A and B. In addition, the character "/" herein generally indicates that the former and latter associated objects are in a logical relationship of "or".

In this application, terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Without further limitation, in this application, the use of the phrases "comprising," "including," "having," or other similar expressions, is intended to cover a non-exclusive inclusion, and these expressions do not exclude the presence of additional elements in a process, method, or article that includes the elements, such that a process, method, or article that includes a list of elements may include not only those elements defined, but other elements not expressly listed, or may include other elements inherent to such process, method, or article.

As is understood in the "review guidelines," in this application, the terms "greater than," "less than," "more than," and the like are to be understood as excluding the number; the expressions "above", "below", "within" and the like are understood to include the present numbers. In addition, in the description of the embodiments of the present application, "a plurality" means two or more (including two), and expressions related to "a plurality" similar thereto are also understood, for example, "a plurality of groups", "a plurality of times", and the like, unless specifically defined otherwise.

In the description of the embodiments of the present application, spatially relative expressions such as "central," "longitudinal," "lateral," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used, and the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the specific embodiments or drawings and are only for convenience of describing the specific embodiments of the present application or for the convenience of the reader, and do not indicate or imply that the device or component in question must have a specific position, a specific orientation, or be constructed or operated in a specific orientation and therefore should not be construed as limiting the embodiments of the present application.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured," and "disposed" used in the description of the embodiments of the present application are to be construed broadly. For example, the connection can be a fixed connection, a detachable connection, or an integrated arrangement; it can be mechanical connection, electrical connection, and communication connection; they may be directly connected or indirectly connected through an intermediate; which may be communication within two elements or an interaction of two elements. Specific meanings of the above terms in the embodiments of the present application can be understood by those skilled in the art to which the present application pertains in accordance with specific situations.

Referring to fig. 3 to 9, the present embodiment provides an ultrafast laser fiber modulation frequency selector 1, as shown in fig. 3, including a pulse laser light source connection end, the pulse laser light source connection end is used for connecting with a pulse laser light source, and further including a first collimator 12, an acousto-optic switch 13, a second collimator 14, a third collimator 15, and a fourth collimator 16, where the pulse laser light source connection end is connected with an input end of the first collimator 12 through a fiber, and laser of the first collimator 12 enters an input end of the second collimator 14 after being incident to the acousto-optic switch 13 and modulated by the acousto-optic switch 13. The output end of the second collimator 14 is connected with the input end of a third collimator 15 through an optical fiber, the laser of the third collimator 15 enters the acousto-optic switch 13 and enters the input end of a fourth collimator 16 after being modulated by the acousto-optic switch 13, and the output end of the fourth collimator 16 is connected with the laser output end of the modulation frequency selector 1. The utility model discloses do not prescribe a limit to the position of first collimator and third collimator, can be in acousto-optic switch 13 with one side also can be in acousto-optic switch 13's different sides. When the collimator is on different sides, the first collimator 12 enters from one side of the acousto-optic switch 13 and exits from the other side of the acousto-optic switch 13 to enter the input end of the second collimator 14, and the third collimator 15 enters from the other side of the acousto-optic switch 13 and exits from one side of the acousto-optic switch 13 to enter the input end of the fourth collimator 16. When on the same side, the first collimator 12 enters the input end of the second collimator 14 after entering from one side of the acousto-optic switch 13 and exiting from the other side of the acousto-optic switch 13, and the third collimator 15 enters the input end of the fourth collimator 16 after entering from one side of the acousto-optic switch 13 and exiting from the other side of the acousto-optic switch 13.

The pulse laser light source is also called a pulse laser. Lasers are operationally classified into continuous lasers and pulsed lasers. The pulse laser is a laser in which a single laser pulse has a width of less than 0.25 second and works at a certain time interval, and the pulse laser light source 11 can emit intermittent laser pulses. The optical fiber is a simple word of an optical fiber, the optical fiber is made of transparent glass or plastic and can be used as a light conduction tool, and light is subjected to total reflection on the inner surface of the optical fiber, so that the light is transmitted through the optical fiber and is transmitted from one end of the optical fiber to the other end of the optical fiber. The collimator belongs to an optical element for input and output of an optical fiber communication optical device, has a simple structure, and is formed by accurately positioning a tail fiber and a self-focusing lens. The collimator is used for converting the divergent light from the optical fiber into parallel light through a similar convex lens arranged in front of the collimator and then emitting the parallel light. The collimator may also couple external parallel (near parallel) light into a single mode fiber.

The utility model discloses at the during operation, at first pulse laser light source 11 produces the higher laser pulse of frequency, and laser pulse enters into acousto-optic switch 13 behind first collimator 12, and whether acousto-optic switch 13 can control the light of first collimator 12 and incide into second collimator 14 to can modulate the number of laser pulses, reduce the pulse quantity in the unit interval, realize the modulation. The modulated laser pulse enters the second collimator 14, is transmitted into the third collimator 15 by light, and finally enters the acousto-optic switch 13 by the output end of the third collimator 15, and the acousto-optic switch 13 performs the same modulation on the number of laser pulses again. Because the modulation time is the same, the modulation of the laser pulse twice can be ensured to be completed according to the required requirements. Therefore, the laser pulse is modulated for the first time by the acousto-optic switch 13 through the first collimator 12 and the second collimator 14, the modulated laser pulse passes through the third collimator 15 and the fourth collimator 16, the modulated laser pulse is output after being modulated for the second time by the acousto-optic switch 13, and after twice modulation, the frequency of the laser pulse output by the modulation frequency selector 1 is stable, so that the high on-off ratio of the modulation frequency selector 1 is realized.

The technical route of a general ultrafast laser is as follows: use high frequency picosecond or femto second high frequency seed source earlier, then pass through the utility model discloses the optical fiber modulator (frequency selector) that mentions, with high frequency pulse seed source frequency selection to the low frequency, then carry out the pulse width broadening again, carry out pulse amplification again, carry out pulse compression at last, output ultrafast laser.

The specific modulation effect of the optical fiber modulation frequency selector of the utility model is shown in fig. 4, and when the high-frequency pulse (such as 6 MHZ) is selected to the low-frequency pulse (such as 3 MHZ) in the prior art, the pulse that has some smalls leaks, such as the small pulse in the upper right of fig. 4. These small pulses are then amplified by the amplifier in the following, so that the amplification efficiency of the 3MHz pulses is greatly compromised, and the frequency is not strictly 3MHz, but is also 6MHz (the total frequency of the large and small pulses is 6 MHz). The utility model discloses a pulse after modulation frequency selector modulation is shown as figure 4 right side below, has eliminated little pulse basically, consequently the small pulse amplification can not appear, influences the problem that big pulse amplification effect and pulse frequency rise again. The utility model discloses can improve present switch than by the tradition >30DB/40DB to >60DB/80 DB's effect, realized pulse modulation's high on-off ratio.

The utility model discloses when the practical application, the utility model discloses modulation frequency selector can make a unit alone and sell, as shown in fig. 3, perhaps as shown in fig. 5, can make an equipment together with pulse laser light source 11 and sell, and pulse laser light source 11 is unnecessary when actually selling promptly, and pulse laser light source 11 in the drawing only serves as the explanation, and the product is not necessarily to contain pulse laser light source 11.

In some embodiments, in order to achieve laser output under different conditions, as shown in fig. 6, further, the modulation frequency selector 1 in this embodiment further includes a first optical path switch 17, a common input end of the first optical path switch 17 is connected to an output end of the second collimator 14 through an optical fiber, an output end of the first optical path switch 17 is connected to an input end of the third collimator 15, and another output end of the first optical path switch 17 is connected to a laser output end of the modulation frequency selector 1 through an optical fiber. The optical path switcher is a device for adjusting the path of the light rays, so that the light rays form a preset optical path along the preset path, and for example, gating of different optical paths can be realized through mechanical switching. For example, the common input terminal of the first light-path switcher 17 may form a light path with one output terminal, or the common input terminal of the first light-path switcher 17 may form a light path with another output terminal. This allows the laser light from the second collimator 14 to be output to the third collimator 15 or directly through an optical fiber. Thus, the pulsed laser light source 11 can be selected to output directly from the second collimator 14 or output again after passing through the acousto-optic switch 13 by switching the first optical path switch 17 as required. And selection of different laser powers and switching ratios is realized.

In the above embodiment, the other output end of the first optical path switch 17 directly outputs alone, or may be combined with the output end of the fourth collimator 16 through an optical fiber combiner 18 and then output, as shown in fig. 7. In some embodiments, in order to realize the optical path control of the output, as shown in fig. 8, the present invention further includes a second optical path switch 19, one input end of the second optical path switch 19 is connected to the output end of the fourth collimator 16, another input end of the second optical path switch 19 is connected to another output end of the first optical path switch 17 through an optical fiber, and a common output end of the second optical path switch 19 is connected to the laser output end of the modulation frequency selector 1. Thus, by the first optical path switcher 17 and the second optical path switcher 19, two kinds of optical path gating conditions can be set, respectively. First, the light path is led out from the second collimator 14, passes through the first light path switch 17, is communicated to the third collimator 15, passes through the acousto-optic switch 13, passes through the fourth collimator 16, and is finally outputted by the second light path switch 19. Second, the optical path is directly outputted from the second optical path switch 19 after passing through the first optical path switch 17 after exiting from the second collimator 14. Therefore, the laser pulse can be controlled to pass through the acousto-optic switch 13 once or pass through the acousto-optic switch 13 twice, and the selection of different laser powers and on-off ratios is realized.

In order to amplify the laser pulse, in some embodiments, further, as shown in fig. 9, the modulation frequency selector 1 of the present invention further includes a laser amplifier 20, and the output end of the fourth collimator 16 passes through the laser amplifier 20 and then is connected to the laser output end of the modulation frequency selector 1. In many practical embodiments, a high quality and high power laser source is required, but in general, the output power or energy of the laser is limited. In order to increase power or energy, the laser amplifier 20 is used. The laser amplifier 20 is a device for amplifying energy (power) of light by using stimulated radiation of light. By employing the laser amplifier 20, the quality of the laser light (including pulse width, line width, polarization characteristics, etc.) can be maintained while achieving high laser energy or power. The utility model discloses can realize the amplification of the laser pulse after the modulation, satisfy powerful application scene. In the above embodiment with the first optical path switch 17, the laser amplifier 20 may also be used to amplify the laser beam directly coming out of the first optical path switch 17, so as to amplify the pulse laser beam.

In order to realize the control to components such as first light path switch 17, second light path switch 19, reputation switch 13, laser amplifier 20 and pulse laser light source 11, the utility model discloses still include control chip, control chip with first light path switch 17 is connected, control chip is used for controlling the switching of first light path switch 17. The control chip can receive the instruction of the user to realize control, or in some embodiments, can control according to some parameters. Specifically, the control chip is configured to obtain that the pulse parameter is greater than a preset value, and then automatically control the first optical path switcher 17 to switch to the common input end of the first optical path switcher 17 to be connected to an output end of the first optical path switcher 17. Therefore, after a user selects parameters in the system, the control chip can select a proper light path to output according to the parameters, and optimal laser pulse output is realized. Further, the pulse parameter is a pulse frequency, or may be a pulse power or the like. The pulse frequency is the number of times of effective pulses occurring in the pulse gap in a unit time, and the pulse frequency can be reduced by the acousto-optic switch 13, which also results in the reduction of the laser power. In some scenarios where the optical path switch 17 is not sensitive to laser frequency but is sensitive to power, the laser pulse can be selected to be directly connected to the output of the modulation frequency selector 1.

The control chip is only required to realize control, and preferably, the control chip is a single chip microcomputer. The single chip computer is an integrated circuit chip, which is a small and perfect microcomputer system formed by integrating the functions of a central processing unit CPU with data processing capacity, a random access memory RAM, a read only memory ROM, various I/O ports, an interrupt system, a timer/counter and the like (possibly comprising a display driving circuit, a pulse width modulation circuit, an analog multiplexer, an A/D converter and the like) on a silicon chip by adopting a super-large scale integrated circuit technology, and is widely applied to the field of industrial control. An ARM series single chip microcomputer is common.

Preferably, the pulsed laser light source 11 is a picosecond laser light source. The picosecond laser source is a laser with a pulse width of picoseconds, i.e. the interval between two laser pulses is in the order of picoseconds. The picosecond laser light source has the characteristics of picosecond-level ultrashort pulse width, adjustable repetition frequency, high pulse energy and the like, has increasingly wide application in the fields of biomedicine, optical parametric oscillation, biological microscopic imaging and the like, and gradually becomes an increasingly important tool in a modern biological imaging and analyzing system.

In the preferred embodiment of the present invention, the acousto-optic switch 13 is an acousto-optic crystal. When the acousto-optic crystal is propagated in the crystal through ultrasonic waves, elastic stress is generated in the crystal, the refractive index of the crystal is periodically changed to form a grating, when light passes through the crystal forming the grating, interaction is generated, the staged conduction of pulse laser is realized, and the modulation of laser pulse is realized. The acousto-optic modulator in this embodiment may be of such a structure as shown in FIG. 1.

The above embodiment of the utility model can be combined arbitrarily to form the more perfect embodiment of function. The embodiment of the utility model discloses a primary action is through first collimator 12 and second collimator 14 for laser pulse carries out the modulation for the first time through acousto-optic switch 13, and laser pulse after the modulation can select whether to pass through third collimator 15 and fourth collimator 16 again, can select to pass through acousto-optic switch 13 again and carry out modulation back output once more, through twice modulation back, makes modulation frequency selector 1 output laser pulse frequency stable, has realized the high on-off ratio of modulation frequency selector 1. The laser pulse output with larger power can be realized through one-time modulation, and the laser pulse requirements of different conditions are met.

It should be noted that, although the above embodiments have been described herein, the scope of the present invention is not limited thereby. Therefore, based on the innovative concept of the present invention, changes and modifications made to the embodiments described herein, or equivalent structures or equivalent flow changes made by using the contents of the specification and the drawings of the present invention, directly or indirectly apply the above technical solutions to other related technical fields, all included in the scope of the present invention.

Claims (10)

1. An ultrafast laser fiber modulation frequency selector is characterized in that: the pulse laser frequency selector comprises a pulse laser light source connecting end, a first collimator, an acousto-optic switch, a second collimator, a third collimator and a fourth collimator, wherein the pulse laser light source connecting end is used for being connected with a pulse laser light source, the pulse laser light source connecting end is connected with the input end of the first collimator through an optical fiber, laser of the first collimator enters the acousto-optic switch and enters the input end of the second collimator after being modulated by the acousto-optic switch, the output end of the second collimator is connected with the input end of the third collimator through the optical fiber, laser of the third collimator enters the acousto-optic switch and enters the input end of the fourth collimator after being modulated by the acousto-optic switch, and the output end of the fourth collimator is connected with the laser output end of the modulation frequency selector.

2. The ultrafast laser fiber modulation frequency selector of claim 1, wherein: the optical path switching device comprises a first optical path switching device, a second optical path switching device and a frequency selector, wherein a public input end of the first optical path switching device is connected with an output end of the second collimator through an optical fiber, an output end of the first optical path switching device is connected with an input end of the third collimator, and another output end of the first optical path switching device is connected with a laser output end of the frequency selector through an optical fiber.

3. The ultrafast laser fiber modulation frequency selector of claim 2, wherein: the optical path switching device comprises a first optical path switcher, a second optical path switcher, a third optical path switcher and a fourth optical path switcher, wherein one input end of the second optical path switcher is connected with the output end of the fourth collimator, the other input end of the second optical path switcher is connected with the other output end of the first optical path switcher through an optical fiber, and the public output end of the second optical path switcher is connected with the laser output end of the modulation frequency selector.

4. The ultrafast laser fiber modulation frequency selector of claim 1, wherein: the output end of the fourth collimator is connected with the laser output end of the modulation frequency selector after passing through the laser amplifier.

5. The ultrafast laser fiber modulation frequency selector of claim 2, wherein: the control chip is connected with the first light path switcher and used for controlling the first light path switcher to switch.

6. The ultrafast laser fiber modulation frequency selector of claim 5, wherein: the control chip is used for automatically controlling the first light path switcher to switch to the public input end of the first light path switcher after the pulse parameter is larger than the preset value, and the public input end of the first light path switcher is connected with an output end of the first light path switcher.

7. The ultrafast laser fiber modulation frequency selector of claim 6, wherein: the pulse parameter is a pulse frequency.

8. The ultrafast laser fiber modulation frequency selector of claim 5, wherein: the control chip is a single chip microcomputer.

9. The ultrafast laser fiber modulation frequency selector of any one of claims 1 to 8, wherein: the pulse laser light source is a picosecond laser light source.

10. The ultrafast laser fiber modulation frequency selector of any one of claims 1 to 8, wherein: the acousto-optic switch comprises an acousto-optic crystal, a transducer and a driving circuit.

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