CN113031363A - Light beam purification device - Google Patents
Light beam purification device Download PDFInfo
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- CN113031363A CN113031363A CN202110177052.6A CN202110177052A CN113031363A CN 113031363 A CN113031363 A CN 113031363A CN 202110177052 A CN202110177052 A CN 202110177052A CN 113031363 A CN113031363 A CN 113031363A
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0938—Using specific optical elements
- G02B27/0994—Fibers, light pipes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
Abstract
The invention discloses a light beam purification device, and relates to the technical field of optical fibers. The device includes: the optical fiber comprises a first optical fiber coupler, a multi-mode optical fiber, a single-mode optical fiber, a phase modulator, a single-mode and multi-mode optical fiber fusion point and a GI multi-mode optical fiber. According to the invention, the first optical fiber coupler is utilized to divide input signal light into two paths, one path of signal light with more energy is transmitted to the GI multimode optical fiber through the multimode optical fiber, the other path of signal light with less energy is transmitted to the GI multimode optical fiber through the single mode optical fiber, the phase modulator and the single mode-multimode optical fiber fusion point, the two paths of signal light meet in the GI multimode optical fiber and then interact to generate a nonlinear optical effect, and pulse light beams can be purified, so that the quality of output light beams is improved.
Description
Technical Field
The invention relates to the technical field of optical fibers, in particular to a light beam purification device.
Background
The beam quality is always one of the important indexes for measuring the laser quality in the laser technology, and is especially important in scientific research and engineering technology. In the field of optical fibers, multimode optical fibers can bear beams with high power or energy due to large core diameters, are generally applied to high-power fiber laser technology, and are widely used along with the recent trend of high-power development of fiber lasers. However, the use of multimode fibers can cause the transmission mode to be multimode, resulting in poor output beam quality.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a light beam purification device which can improve the quality of the output light beam of the multimode optical fiber.
The light beam purification device according to the embodiment of the invention comprises:
the first optical fiber coupler is used for receiving input signal light and dividing the input signal light into a first path of signal light and a second path of signal light;
the multimode optical fiber is connected with the first optical fiber coupler and is used for transmitting the first path of signal light;
the single-mode optical fiber is connected with the first optical fiber coupler and is used for transmitting the second path of signal light;
the phase modulator is connected with the single-mode optical fiber and is used for carrying out frequency shift on the second path of signal light;
the single-mode and multi-mode optical fiber welding point is connected with the phase modulator and is used for selecting the mode of the second path of signal light after frequency shift as a fundamental mode;
and the GI multimode optical fiber is connected with the multimode optical fiber and the single-mode-multimode optical fiber fusion point and used for enabling the first path of signal light and the second path of signal light to meet in the GI multimode optical fiber so as to enable the first path of signal light and the second path of signal light to interact in the GI multimode optical fiber and realize beam purification.
The light beam purification device provided by the embodiment of the invention has at least the following beneficial effects:
according to the light beam purification device provided by the embodiment of the invention, the input signal light is divided into two paths by using the optical fiber coupler, one path of signal light with more energy is transmitted to the GI multimode optical fiber through the multimode optical fiber, the other path of signal light with less energy is transmitted to the GI multimode optical fiber through the single mode optical fiber, the phase modulator and the single mode-multimode optical fiber fusion point, the two paths of signal light meet in the GI multimode optical fiber and then interact to generate a nonlinear optical effect, and the pulse light beam can be purified, so that the quality of the output light beam is improved.
According to some embodiments of the invention, the apparatus further comprises:
and the multimode optical fiber circulator is respectively connected with the multimode optical fiber and the GI multimode optical fiber.
According to some embodiments of the invention, the pulse width of the input signal light is greater than or equal to a phonon field lifetime of a brillouin scattering effect;
the device further comprises:
a first output port connected to the multimode optical fiber circulator;
the phase modulator is used for carrying out Brillouin frequency shift on the second path of signal light;
the GI multimode fiber is configured to converge the first path of signal light and the second path of signal light, so that the first path of signal light and the second path of signal light are output from the first output port through the multimode fiber circulator after a brillouin scattering effect occurs in the GI multimode fiber.
According to some embodiments of the invention, a pulse width of the input signal light is less than a phonon field lifetime of the brillouin scattering effect;
the device further comprises:
a second fiber coupler connected to the GI multimode fiber;
a second output port connected to the second fiber coupler;
the GI multimode fiber is configured to converge the first path of signal light and the second path of signal light, so that the first path of signal light and the second path of signal light generate a kerr effect in the GI multimode fiber and then are output from the second output port through the second fiber coupler.
According to some embodiments of the invention, the apparatus further comprises:
and the optical fiber isolator is connected with the first optical fiber coupler and is used for isolating the input signal light.
According to some embodiments of the present invention, an energy ratio of the first signal light to the second signal light is 99: 1.
according to some embodiments of the invention, the GI multimode fiber has a core diameter of 105 μm, a length of 100m, and a grading index of 2.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The invention is further described with reference to the following figures and examples, in which:
FIG. 1 is a schematic structural diagram of a light beam purification apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a light beam purification apparatus according to another embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a light beam purification apparatus according to another embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a light beam purification apparatus according to another embodiment of the present invention;
fig. 5 is a schematic diagram of a light spot of an input signal light according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a light spot of an output beam at a first output port according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a light spot of an output light beam at a second output port according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a light beam purification apparatus according to another embodiment of the present invention.
Reference numerals:
a first optical fiber coupler 100, a multimode optical fiber 200, a single-mode optical fiber 300, a phase modulator 400, a single-mode-multimode optical fiber fusion point 500, a GI multimode optical fiber 600, a multimode optical fiber circulator 700, a first output port 800, a second output port 900, a second optical fiber coupler 1000, and an optical fiber isolator 1100.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the description of the present invention, the meaning of a plurality is one or more, the meaning of a plurality is two or more, and the above, below, exceeding, etc. are understood as excluding the present numbers, and the above, below, within, etc. are understood as including the present numbers. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The beam quality is always one of the important indexes for measuring the laser quality in the laser technology, and is especially important in scientific research and engineering technology. In the field of optical fibers, multimode optical fibers can bear beams with high power or energy due to large core diameters, are generally applied to high-power fiber laser technology, and are widely used along with the recent trend of high-power development of fiber lasers. However, the use of multimode fibers can cause the transmission mode to be multimode, resulting in poor output beam quality.
How to improve the quality of the output beam of the multimode fiber has been a hot point discussed in the field of high power fiber lasers. In the related art, the special optical fibers such as the tapered optical fiber and the photonic crystal optical fiber can be used for obtaining high-beam-quality output light of the large-core-diameter optical fiber, but the special optical fibers are not mature in technology and are very expensive in price.
In view of the above, embodiments of the present invention provide a light beam purification apparatus, which uses a low-cost GI (Graded Index) multimode fiber to purify a pulse light beam in the GI multimode fiber by using an interaction (a nonlinear optical effect such as a kerr effect and a stimulated brillouin scattering effect) occurring in the fiber, thereby improving the quality of an output light beam of the multimode fiber.
As shown in fig. 1, the present invention provides a light beam purification apparatus including:
the first optical fiber coupler 100, the first optical fiber coupler 100 is configured to receive input signal light, and divide the input signal light into a first path of signal light and a second path of signal light;
the multimode optical fiber 200 is connected with the first optical fiber coupler and used for transmitting the first path of signal light;
the single-mode fiber 300, the single-mode fiber 300 is connected to the first fiber coupler 100, and is configured to transmit the second path of signal light;
the phase modulator 400, the phase modulator 400 is connected to the single-mode fiber 300, and is configured to perform frequency shift on the second path of signal light;
the single-mode and multi-mode optical fiber fusion point 500 is connected with the phase modulator 400, and is used for selecting the mode of the second path of frequency-shifted signal light as a fundamental mode;
the GI multimode optical fiber 600, the GI multimode optical fiber 600 is connected to the multimode optical fiber 200 and the single mode-multimode optical fiber fusion point 500, and is configured to enable the first path of signal light and the second path of signal light to meet in the GI multimode optical fiber 600, so that the first path of signal light and the second path of signal light interact in the GI multimode optical fiber 600, and beam purification is achieved.
According to the light beam purification device provided by the embodiment of the invention, the input signal light is divided into two paths by using the optical fiber coupler, one path of signal light with more energy is transmitted to the GI (Graded Index) multimode fiber through the multimode fiber, the other path of signal light with less energy is transmitted to the GI multimode fiber in a fundamental mode through the single mode fiber, the phase modulator and the single mode-multimode fiber fusion point, the two paths of signal light interact after meeting in the GI multimode fiber to generate a nonlinear optical effect, and the pulse light beam can be purified, so that the quality of the output light beam is improved.
In some embodiments, the optical path difference of the two signal lights needs to be controlled so that they meet in the GI multimode fiber.
In some embodiments, as shown in fig. 2, the beam purification apparatus further comprises:
the multimode fiber circulator 700 and the multimode fiber circulator 700 are respectively connected with the multimode fiber 200 and the GI multimode fiber 600.
In some embodiments, the multimode optical fiber 200 is connected to the first fiber coupler 100 for transmitting the first signal light to the multimode fiber circulator 700, and the multimode fiber circulator 700 transmits the first signal light to the GI multimode optical fiber 600.
In some embodiments, the first signal light and the second signal light may be transmitted in opposite directions after meeting and performing some interaction in the GI multimode fiber 600. To solve this problem, the multimode fiber circulator 700 is used, and the multimode fiber circulator 700 may enable the output of the signal light transmitted in the reverse direction. It will be appreciated that other devices capable of outputting a reverse beam, such as fiber couplers, may be used.
In some embodiments, the multimode optical fiber 200 may be any multimode optical fiber as long as it can be connected to the multimode optical fiber circulator 700. It should be noted that the length of the multimode optical fiber 200 is preferably relatively short because the longer the length of the multimode optical fiber, the more likely the brillouin scattering effect occurs, while the stimulated brillouin scattering effect is not desired to occur in the multimode optical fiber 200, and the stimulated brillouin scattering effect is desired to occur only in the GI multimode optical fiber 200, and therefore, the shorter the length of the multimode optical fiber 200 is, the better the other conditions are satisfied.
In some embodiments, the pulse width of the input signal light is divided into two cases: the lifetime of the phonon field is greater than or equal to that of the Brillouin scattering effect and is less than that of the Brillouin scattering effect. The optical effects of the input signal light with different pulse widths in the GI multimode fiber are also different, and the final output port is also different. In some embodiments, the lifetime of the phonon field of the brillouin scattering effect depends on the type of the optical fiber, and is generally on the order of picoseconds, which is not particularly limited in this embodiment. Two cases are described in detail below:
in some embodiments, if the pulse width of the input signal light is greater than or equal to the lifetime of the phonon field of the brillouin scattering effect, correspondingly, as shown in fig. 3, the light beam purification apparatus further includes:
a first output port 800, the first output port 800 being connected to the multimode optical fiber circulator 700;
the phase modulator 400 is configured to perform brillouin frequency shift on the second path of signal light;
the GI multimode fiber 600 is configured to converge the first path of signal light and the second path of signal light, so that the first path of signal light and the second path of signal light are output from the first output port 800 through the multimode fiber circulator 700 after a brillouin scattering effect occurs in the GI multimode fiber.
In some embodiments, with reference to fig. 3, if the pulse width of the input signal light is greater than or equal to the lifetime of the phonon field of the brillouin scattering effect, the input signal light passes through 99: the first optical fiber coupler 100 of 1 is divided into 99% of a first path of signal light and 1% of a second path of signal light (an upper path and a lower path). Wherein, 99% of the first path of signal light enters the multimode optical fiber 200, is guided by the multimode optical fiber circulator 700 after being transmitted through the multimode optical fiber 200, and enters the GI multimode optical fiber 600 in the forward direction. The remaining 1% of the second path of signal light enters the single mode fiber 300, undergoes brillouin frequency shift using the phase modulator 400, becomes seed light which is then stimulated with brillouin scattering effect, is induced by the single mode-multimode fiber fusion point 500 to enter the GI multimode fiber 600, and meets the first path of signal light with 99% of energy in the GI multimode fiber 600. The first path of signal light of the GI multimode fiber 600 incident in the forward direction interacts with the seed light (the second path of signal light) incident in the backward direction to generate a stimulated brillouin scattering amplification effect, the first path of signal light originally having 99% energy becomes pump light in the stimulated brillouin scattering amplification process, and transfers energy to the seed light originally having only 1% energy, the amplified seed light has most energy in the incident signal light and is transmitted to the multimode fiber circulator 700 in the backward direction, and the amplified signal light is output from the first output port 800 according to the principle of the fiber circulator.
In some embodiments, when the input signal light is a phonon field lifetime with a pulse width greater than or equal to the brillouin effect, the reason for outputting a high-quality light beam is:
(1) the pulse width of input signal light is larger than the service life of Brillouin phonons, the frequency difference between 1% of reversely transmitted seed light and 99% of forward transmitted pumping light is just Brillouin frequency difference, and the stimulated Brillouin scattering amplification effect is easy to occur;
(2) when 1% of seed light passes through the single-mode multi-mode optical fiber fusion point 500, mode selection excitation of a fundamental mode is performed (that is, only the fundamental mode is excited in the multi-mode optical fiber), that is, before stimulated brillouin scattering occurs in the GI multi-mode optical fiber 600, the seed light is the fundamental mode light with good beam quality;
(3) the Stokes light (amplified seed light) can keep the seed light during the stimulated Brillouin scattering amplification processModes and modalities. Therefore, even if the beam quality of the input signal light is poor (as shown in fig. 5, it is the optical spot pattern of the input signal light), after the stimulated brillouin scattering amplification effect occurs, the light beam that is transmitted in the reverse direction and output from the first output port 800 is still the fundamental mode light beam with good beam quality, the output optical spot is as shown in fig. 6, and the beam quality factor M is2Is 1.29.
In some embodiments, if the pulse width of the input signal light is less than the phonon field lifetime of the brillouin scattering effect. Correspondingly, as shown in fig. 4, the beam purification apparatus further includes:
a second fiber coupler 1000, the second fiber coupler 1000 being connected to the GI multimode fiber 600;
a second output port 900, wherein the second output port 900 is connected to the second optical fiber coupler 1000;
the GI multimode fiber 600 is configured to converge the first path of signal light and the second path of signal light, so that the first path of signal light and the second path of signal light generate a kerr effect in the GI multimode fiber 600 and then are output from the second output port 900 through the second fiber coupler 1000.
In some embodiments, referring to fig. 4, if the pulse width of the input signal light is smaller than the lifetime of the phonon field of the brillouin scattering effect, i.e. it is an ultra-short pulse of picosecond or femtosecond level, the input signal light passes through 99: the first optical fiber coupler 100 of 1 is divided into 99% of a first path of signal light and 1% of a second path of signal light (an upper path and a lower path). Wherein, 99% of the first path of signal light enters the multimode optical fiber 200, is guided by the multimode optical fiber circulator 700 after being transmitted through the multimode optical fiber 200, and enters the GI multimode optical fiber 600 in the forward direction. The remaining 1% of the second path of signal light enters the single mode fiber 300, generates a brillouin frequency shift using the phase modulator 400, is induced by the single mode-multimode fiber fusion point 500 to enter the GI multimode fiber 600, and meets the first path of signal light having 99% energy in the GI multimode fiber 600. Because the pulse width of the input signal light is less than the phonon lifetime of the stimulated brillouin scattering, the stimulated brillouin scattering cannot occur, and therefore 99% of the first path signal light and 1% of the seed light (the second path signal light) do not interact with each other and continue to be transmitted after meeting each other. However, due to the beam converging action of the GI multimode fiber 600, the ultrashort pulse beam may generate kerr effect beam purification action in the GI multimode fiber 600, and the purified beam is output from the second output port 900 after passing through the second fiber coupler 1000.
In some embodiments, when the input signal light is an ultrashort pulse with a pulse width smaller than the lifetime of the phonon field of the brillouin scattering effect, i.e., in the picosecond or femtosecond order, the reason for outputting a high-quality light beam is:
(1) the pulse width of the input signal light is less than the service life of the Brillouin phonons, stimulated Brillouin scattering amplification cannot occur after the seed light meets the pump light, and the pump light continues to be transmitted in the forward direction;
(2) the GI multimode fiber 600 induces the ultrashort pulse light beam to generate the kerr effect light beam purification effect due to the light beam convergence effect, converts the pump light from the multimode light beam into the fundamental mode light beam, and finally outputs the fundamental mode light beam from the second output port 900 in the form of the fundamental mode light beam with good light beam quality, the output light spot is shown in fig. 7, and the light beam quality factor M is2Is 1.34.
In combination with the above description of the two cases of the pulse width of the input signal light, it can be seen that the light beam purification apparatus of the present embodiment can distinguish the pulse width by itself, so as to perform adaptive purification on the input signal light with different pulse widths. In other words, when the input signal light has any pulse width, the light beam can be adaptively cleaned, and thus a high-quality light beam can be output. Specifically, the input signal light having a pulse width below the lifetime of the phonon field of the brillouin scattering effect is purified by the kerr effect, and the purified light beam is output from the second output port 900; the input signal light having a pulse width of more than the lifetime of the phonon field of the brillouin scattering effect is purified by the stimulated brillouin scattering effect, and the purified light beam is output from the first output port 800. That is, the optical beam purification apparatus of the present embodiment can also detect to which level the pulse width of the input signal light belongs, according to which output port the optical beam is output from.
In some embodiments, the GI multimode fiber 600 is the core device of the whole beam purification apparatus, and the stimulated brillouin scattering effect or kerr effect is generated in this section of fiber. The GI multimode fiber is cheap and easy to purchase, the diameter of the fiber core and the length of the fiber can be changed according to the intensity of input signal light, and a square-law GI multimode fiber with the core diameter of 105 mu m, the length of the fiber of 100m and the gradient index of 2 is generally recommended.
In some embodiments, the beam purification apparatus further comprises:
the optical fiber isolator is connected to the first optical fiber coupler 100, and is configured to isolate input signal light.
In some embodiments, the fiber isolator is connected to the first fiber coupler 100, and the input signal light is transmitted to the first fiber coupler 100 after being isolated by the fiber isolator. Because the transmission direction of the optical fiber isolator is unidirectional, a small amount of light with the stimulated Brillouin scattering amplification effect can be prevented from returning to damage the input signal light.
In some embodiments, the energy ratio of the first signal light to the second signal light is 99:1 may be in other proportions, which is not specifically limited in this embodiment.
The beam purification apparatus of the present invention is described in a more complete embodiment as follows:
as shown in fig. 8, the input signal light is divided into two paths, i.e., an upper path and a lower path, by the first optical fiber coupler 100 of 99:1 after passing through the optical fiber isolator 1100. Wherein, 99% of the signal light of the upper path enters the multimode fiber 200, is guided by the multimode fiber circulator 700 after being transmitted through the multimode fiber 200, and enters the GI multimode fiber 600 in the forward direction. The remaining 1% of the signal light enters the single mode fiber 300 from the lower path, generates a brillouin frequency shift using the phase modulator 400, becomes seed light which is then stimulated with a brillouin scattering effect, is induced by the single mode-multimode fiber fusion point 500 to enter the multimode fiber (the left half of the partially enlarged view of the single mode-multimode fiber fusion point 500 is the single mode fiber, the right half is the multimode fiber, and the center point of the single mode fiber and the center point of the multimode fiber are on the same straight line), and reversely enters the GI multimode fiber 600 through the 99:1 second fiber coupler 1000, where the GI multimode fiber 600 meets forward transmission signal light having 99% energy.
At this time, if the input signal light is a phonon field with a pulse width greater than or equal to the lifetime of the brillouin scattering effect, the signal light of the GI multimode fiber 600 that enters in the forward direction interacts with the seed light that enters in the backward direction to generate a stimulated brillouin scattering amplification effect, the signal light that originally has 99% of energy becomes pump light in the stimulated brillouin scattering amplification process, and the energy is transferred to the seed light that originally has only 1% of energy, the amplified seed light has most of the energy in the incident signal light, and is transmitted to the multimode fiber circulator 700 in the backward direction, and according to the fiber circulator principle (forward transmission a enters B and backward transmission B enters C), the amplified signal light is output from the first output port 800.
If the pulse width of the input signal light is smaller than the phonon field life of the brillouin scattering effect, that is, if the pulse width is a picosecond or femtosecond-level ultrashort pulse, stimulated brillouin scattering cannot occur because the pulse width of the light beam is smaller than the phonon life of the stimulated brillouin scattering, and 99% of the signal light and 1% of the seed light do not interact with each other and continue to be transmitted after meeting each other. However, due to the beam converging action of the GI multimode fiber 600, the ultra-short pulse may generate a kerr effect beam cleaning action in the GI multimode fiber 600, and the cleaned beam is output from the second output port 900 after passing through the second fiber coupler 1000.
In some embodiments, it should be noted that, if the energy of the input signal light is too low to reach the threshold of the stimulated brillouin scattering effect or the kerr effect, the beam purification process in the embodiment of the present invention cannot be performed, so that the embodiment of the present invention is suitable for the input signal light with certain energy. And the pumping utilization rate of the stimulated Brillouin scattering effect and the Kerr effect is in direct proportion to the energy of the input signal light, namely the higher the energy of the input signal light is, the higher the pumping utilization rate is. Therefore, the embodiment of the invention is most suitable for the case of high-power input signal light.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Claims (7)
1. A beam purification apparatus, comprising:
the first optical fiber coupler is used for receiving input signal light and dividing the input signal light into a first path of signal light and a second path of signal light;
the multimode optical fiber is connected with the first optical fiber coupler and is used for transmitting the first path of signal light;
the single-mode optical fiber is connected with the first optical fiber coupler and is used for transmitting the second path of signal light;
the phase modulator is connected with the single-mode optical fiber and is used for carrying out frequency shift on the second path of signal light;
the single-mode and multi-mode optical fiber welding point is connected with the phase modulator and is used for selecting the mode of the second path of signal light after frequency shift as a fundamental mode;
and the GI multimode optical fiber is connected with the multimode optical fiber and the single-mode-multimode optical fiber fusion point and used for enabling the first path of signal light and the second path of signal light to meet in the GI multimode optical fiber so as to enable the first path of signal light and the second path of signal light to interact in the GI multimode optical fiber and realize beam purification.
2. A beam purification apparatus according to claim 1, further comprising:
and the multimode optical fiber circulator is respectively connected with the multimode optical fiber and the GI multimode optical fiber.
3. The beam purification apparatus according to claim 2, wherein the pulse width of the input signal light is greater than or equal to a phonon field lifetime of a brillouin scattering effect;
the device further comprises:
a first output port connected to the multimode optical fiber circulator;
the phase modulator is used for carrying out Brillouin frequency shift on the second path of signal light;
the GI multimode fiber is configured to converge the first path of signal light and the second path of signal light, so that the first path of signal light and the second path of signal light are output from the first output port through the multimode fiber circulator after a brillouin scattering effect occurs in the GI multimode fiber.
4. The beam purification apparatus according to claim 3, wherein the pulse width of the input signal light is smaller than the phonon field lifetime of the Brillouin scattering effect;
the device further comprises:
a second fiber coupler connected to the GI multimode fiber;
a second output port connected to the second fiber coupler;
the GI multimode fiber is configured to converge the first path of signal light and the second path of signal light, so that the first path of signal light and the second path of signal light generate a kerr effect in the GI multimode fiber and then are output from the second output port through the second fiber coupler.
5. The beam purification apparatus of any one of claims 1 to 4, further comprising:
and the optical fiber isolator is connected with the first optical fiber coupler and is used for isolating the input signal light.
6. The beam purification apparatus of any one of claims 1 to 4, wherein the energy ratio of the first signal light to the second signal light is 99: 1.
7. the beam purification apparatus of any one of claims 1 to 4, wherein the GI multimode fiber has a core diameter of 105 μm, a length of 100m, and a grading index of 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110177052.6A CN113031363A (en) | 2021-02-07 | 2021-02-07 | Light beam purification device |
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| CN116154593A (en) * | 2023-04-19 | 2023-05-23 | 武汉中科锐择光电科技有限公司 | Device, system and method for realizing mode self-cleaning of multimode optical fiber amplifier |
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| CN116154593A (en) * | 2023-04-19 | 2023-05-23 | 武汉中科锐择光电科技有限公司 | Device, system and method for realizing mode self-cleaning of multimode optical fiber amplifier |
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