High-repetition-frequency crosstalk-free double-optical-comb fiber laser based on mechanical sharing

Abstract

The invention discloses a high repetition frequency crosstalk-free double-optical comb fiber laser based on mechanical sharing, which comprises a pumping source, an optical coupler and a tunable optical attenuator, and is characterized in that the pumping end of a first wavelength division multiplexer is connected with the output end of the tunable optical attenuator, and the pumping end of a second wavelength division multiplexer is connected with the third port of the optical coupler; the first resonant cavity comprises a dielectric film, a first doped optical fiber, a first single-mode optical fiber and a semiconductor saturable absorption mirror which are connected in sequence, and the first doped optical fiber is connected with the common end of the first wavelength division multiplexer; the second resonant cavity comprises a dielectric film, a second doped optical fiber, a second single-mode optical fiber and a semiconductor saturable absorption mirror which are connected in sequence, and the second doped optical fiber is connected with the common end of the second wavelength division multiplexer; and the optical fiber part of the first resonant cavity and the optical fiber part of the second resonant cavity are tightly arranged at the same position to realize mechanical sharing. The laser provided by the invention can obtain double optical comb output without crosstalk and with higher repetition frequency.

Description

Technical Field

[0001] The present invention relates to the technical field of optical frequency combs, and particularly to a high-repetition-frequency crosstalk-free dual optical comb fiber laser based on mechanical sharing. Background Art

[0002] An optical frequency comb appears as an equally spaced pulse sequence in the time domain and a series of equally spaced teeth in the frequency domain. The dual optical comb technology uses two optical frequency combs with slightly different repetition frequencies for asynchronous sampling in the time domain and multi-heterodyne interference in the frequency domain. Therefore, its beat frequency signal can be down-converted from the high-frequency optical frequency domain to the low-frequency radio frequency domain, so that the information in the optical frequency domain can be reflected in the radio frequency domain to achieve high-speed and high-resolution optical measurement. At present, dual optical comb systems have been widely used in spectroscopy, optical imaging, distance measurement and other fields.

[0003] In a traditional dual optical comb system, two independent mode-locked lasers with a certain difference in repetition frequencies are used as the dual optical comb light sources. To ensure the mutual coherence of the two lasers, an optoelectronic servo system for locking the repetition frequency and the carrier offset frequency is usually introduced. Therefore, such systems are not only complex in structure but also costly. The emerging single-cavity dual optical comb fiber laser can simultaneously generate two mode-locked frequency combs with different repetition frequencies in a single resonant cavity. Due to the common-mode noise suppression ability brought by sharing the resonant cavity, the two optical frequency combs can obtain good relative stability without servo feedback. At present, single-cavity dual optical comb lasers are mainly based on wavelength multiplexing, bidirectional multiplexing and polarization multiplexing methods, with lower cost and simpler structure.

[0004] However, in the current single-cavity dual optical comb fiber lasers, due to the coexistence of two optical frequency combs in the cavity, there is inevitably an interaction between the two optical frequency combs in the cavity, that is, the crosstalk problem. The existence of crosstalk will not only affect the mode-locking quality but also reduce the signal-to-noise ratio of the dual optical comb interference signal. On the other hand, due to the mode competition between the two optical frequency combs in the single-cavity dual optical comb laser cavity, when the resonant cavity length is shortened to increase the repetition frequency of the optical frequency comb, the gain and nonlinear effects in the cavity will decrease, making it difficult for the two optical frequency combs to achieve mode locking simultaneously. Therefore, the repetition frequency of single-cavity dual optical comb mode-locked lasers is relatively low. And the repetition frequency and the repetition frequency difference play an important role in the application of dual optical comb measurement. Increasing the repetition frequency can enable the optical frequency comb to obtain a wider mode interval, and each single tooth has higher energy, which helps to improve the signal-to-noise ratio of the interference signal. In addition, without violating the Nyquist sampling theorem, a higher repetition frequency allows a higher repetition frequency difference, which means that on the one hand, a higher sampling rate can be obtained, and on the other hand, more interference signals can be obtained for averaging within a unit time, which also helps to improve the signal-to-noise ratio.

[0005] In current single-cavity dual-comb fiber lasers, there are common problems such as signal crosstalk between frequency combs and low repetition frequency, which is not conducive to some dual-comb precision measurement applications that require high signal-to-noise ratio and high repetition frequency. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the first purpose of the present invention is to propose a high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing, which can generate a dual-comb without crosstalk problem and can obtain a higher repetition rate than a general single-cavity dual-comb fiber laser, which is suitable for the field of precision measurement.

[0007] To achieve the above object, the first embodiment of the present invention proposes a high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing, comprising:

[0008] A pump source, the pump source being used to emit pump light;

[0009] An optical coupler, a first port of the optical coupler being connected to the pump source;

[0010] A tunable optical attenuator, wherein an input end of the tunable optical attenuator is connected to the second port of the optical coupler;

[0011] A first wavelength division multiplexer, wherein a pump end of the first wavelength division multiplexer is connected to an output end of the tunable optical attenuator;

[0012] a second wavelength division multiplexer, wherein a pump end of the second wavelength division multiplexer is connected to a third port of the optical coupler;

[0013] A first resonant cavity, the first resonant cavity comprising a dielectric film, a first doped optical fiber, a first single-mode optical fiber and a semiconductor saturable absorber mirror connected in sequence, the first doped optical fiber being connected to a common end of the first wavelength division multiplexer;

[0014] a second resonant cavity, the second resonant cavity comprising the dielectric film, the second doped optical fiber, the second single-mode optical fiber and the semiconductor saturable absorber mirror connected in sequence, the second doped optical fiber being connected to a common end of the second wavelength division multiplexer;

[0015] The first doped optical fiber and the second doped optical fiber are packaged into a multi-core optical fiber structure to share a pump source; the first single-mode optical fiber and the second single-mode optical fiber are packaged into a multi-core optical fiber structure to share a semiconductor saturable absorber mirror; the optical fiber part of the first resonant cavity and the optical fiber part of the second resonant cavity are closely arranged in the same position to achieve mechanical sharing, wherein the lengths of the optical fiber part of the first resonant cavity and the optical fiber part of the second resonant cavity are adjustable.

[0016] In addition, the high-repetition-frequency crosstalk-free dual optical comb laser based on mechanical sharing according to the above embodiments of the present invention may further have the following additional technical features:

[0017] According to an embodiment of the present invention, the first doped optical fiber and the second doped optical fiber, and the first single-mode optical fiber and the second single-mode optical fiber achieve mechanical sharing of the first resonant cavity and the second resonant cavity by means of gluing.

[0018] According to another embodiment of the present invention, the first doped optical fiber and the second doped optical fiber, and the first single-mode optical fiber and the second single-mode optical fiber achieve mechanical sharing of the first resonant cavity and the second resonant cavity in the form of a direct multi-core optical fiber.

[0019] According to an embodiment of the present invention, the semiconductor saturable absorber mirror is directly coupled to the multi-core optical fiber end faces of the first single-mode optical fiber and the second single-mode optical fiber respectively.

[0020] According to an embodiment of the present invention, the light spot of the first resonant cavity and the light spot of the second resonant cavity are spatially separated on the semiconductor saturable absorber mirror, avoiding pulse crosstalk.

[0021] According to an embodiment of the present invention, the first doped optical fiber and the second doped optical fiber adopt high-gain optical fibers, and their absorption coefficients exceed 80 dB / m at 1530 nm, which can ensure sufficient gain when shortening the length of the optical fiber in the cavity and realize high-repetition-frequency mode-locked pulses.

[0022] According to an embodiment of the present invention, the dielectric film is formed by covering the end face of the optical fiber sleeve with a multi-layer SiO 2 / Ta 2 O 5 dielectric film. The dielectric film serves as a dichroic mirror, which is completely transmissive to the pump light and partially reflective to the resonant laser wavelength.

[0023] According to an embodiment of the present invention, the pump source divides the pump light into two parts through the optical coupler. One part enters the pump end of the first wavelength division multiplexer after passing through the tunable optical attenuator, and the other part directly enters the pump end of the second wavelength division multiplexer. The common ends of the first wavelength division multiplexer and the second wavelength division multiplexer are both packaged into a structure similar to a multi-core optical fiber. The common end of the first wavelength division multiplexer is fiber-coupled to the first doped optical fiber for coupling the pump light into the first resonant cavity; the common end of the second wavelength division multiplexer is fiber-coupled to the second doped optical fiber for coupling the pump light into the second resonant cavity.

[0024] According to an embodiment of the present invention, the optical coupler is a 1×2 coupler, and the end with a high splitting ratio is used as the second port of the optical coupler and is connected to the input end of the tunable optical attenuator.

[0025] According to an embodiment of the present invention, the multi-core fiber-like structure is formed by encapsulating two corresponding optical fibers in the same ceramic ferrule; or directly using a multi-core optical fiber for flange coupling.

[0026] The present invention adopts the above technical solutions and has the following beneficial effects:

[0027] (1) The dual-comb fiber laser provided by the present invention has two independent resonators, so there is no crosstalk between the output asynchronous pulses; at the same time, different from the single-cavity dual-comb fiber laser, there is no mode competition between the asynchronous pulses during mode locking, so it is easier to achieve asynchronous pulse mode locking with a higher repetition frequency.

[0028] (2) The laser provided by the present invention can adjust the repetition frequency difference between the output asynchronous pulses by adjusting the difference in the lengths of the optical fibers in the two resonators.

[0029] (3) The laser provided by the present invention can adjust the energy difference in the two resonators by adjusting the tunable optical attenuator, so as to adjust the radio frequency signal of the dual-comb beat frequency, and can avoid spectral aliasing when the radio frequency signal approaches the Nyquist bandwidth.

[0030] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG. is a schematic structural diagram of a high-repetition-frequency crosstalk-free dual-comb fiber laser based on mechanical sharing according to an embodiment of the present invention;

[0032] Figure 2 FIG. is a schematic structural diagram of a multi-core fiber-like structure according to an embodiment of the present invention.

[0034] 1. Pump source; 2. Optical coupler; 21. First port of the optical coupler; 22. Second port of the optical coupler; 23. Third port of the optical coupler; 3. Tunable optical attenuator; 4. First wavelength division multiplexer; 41. Pump end of the first wavelength division multiplexer; 42. Common end of the first wavelength division multiplexer; 43. Signal end of the first wavelength division multiplexer; 5. Second wavelength division multiplexer; 51. Pump end of the second wavelength division multiplexer; 52. Common end of the second wavelength division multiplexer; 53. Signal end of the second wavelength division multiplexer; 6. First resonant cavity; 60. Dielectric film; 61. First doped optical fiber; 62. First single-mode optical fiber; 63. Semiconductor saturable absorber; 7. Second resonant cavity; 71. Second doped optical fiber; 72. Second single-mode optical fiber. Detailed implementation manners

[0035] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0036] The high-repetition-rate crosstalk-free dual optical comb fiber laser based on mechanical sharing proposed in the embodiments of the present invention will be described below with reference to the accompanying drawings.

[0037] As Figure 1As shown in the figure, the high-repetition-frequency crosstalk-free dual-comb fiber laser based on mechanical sharing according to the embodiment of the present invention includes: a pump source 1 for emitting pump light; an optical coupler 2, the first port 21 of the optical coupler 2 is connected to the pump source 1; a tunable optical attenuator 3, the input end of the tunable optical attenuator 3 is connected to the second port 22 of the optical coupler 2; a first wavelength division multiplexer 4, the pump end 41 of the first wavelength division multiplexer 4 is connected to the output end of the tunable optical attenuator 3; a second wavelength division multiplexer 5, the pump end 51 of the second wavelength division multiplexer 5 is connected to the third port 23 of the optical coupler 2; a first resonant cavity 6, the first resonant cavity 6 includes a dielectric film 60, a first doped fiber 61, a first single-mode fiber 62 and a semiconductor saturable absorber mirror 63 connected in sequence, the first doped fiber 61 is connected to the input end 42 of the first wavelength division multiplexer 4; a second resonant cavity 7, the second resonant cavity 7 includes a dielectric film 60, a second doped fiber 71, a second single-mode fiber 72 and a semiconductor saturable absorber mirror 63 connected in sequence, the second doped fiber 71 is connected to the input end 52 of the second wavelength division multiplexer 5; the first doped fiber 61 and the second doped fiber 71 are encapsulated into a multi-core fiber-like structure to share the pump source; the first single-mode fiber 62 and the second single-mode fiber 72 are encapsulated into a multi-core fiber-like structure to share the semiconductor saturable absorber mirror 63; the fiber parts of the first resonant cavity 6 and the second resonant cavity 7 are closely arranged at the same position to achieve mechanical sharing, wherein the lengths of the fiber parts of the first resonant cavity 6 and the second resonant cavity 7 are adjustable.

[0038] Specifically, the pump light emitted by the pump source 1 enters the optical coupler 2, and the optical coupler 2 divides the pump light into two parts and pumps them into the first resonant cavity 6 and the second resonant cavity 7 respectively. The tunable optical attenuator 3 can adjust the pump power difference between the first resonant cavity 6 and the second resonant cavity 7. The first wavelength division multiplexer 4 can input pump light into the first resonant cavity 6 and output the laser in the first resonant cavity 6. The second wavelength division multiplexer 5 can input pump light into the second resonant cavity 7 and output the laser in the second resonant cavity 7.

[0039] Furthermore, in the first resonator 6 and the second resonator 7, the dielectric film 60 serves as a dichroic mirror, enhancing the transmission of the pump light and partially reflecting the output laser, and forms the reflecting end faces of the first resonator 6 and the second resonator 7 together with the semiconductor saturable absorber mirror 63; the doped ions in the first doped optical fiber 61 and the second doped optical fiber 71 absorb the pump light and emit laser of the required wavelength (such as 1550 nm) through stimulated emission; the first single-mode optical fiber 62 and the second single-mode optical fiber 72 can provide sufficient nonlinear effects to facilitate pulse mode locking; the semiconductor saturable absorber mirror 63 serves as a mode-locking device, having high absorption for low-intensity light and high transmission for high-intensity light. The first single-mode optical fiber 62 and the second single-mode optical fiber 72 are packaged into a multi-core fiber-like structure and connected to the same semiconductor saturable absorber mirror 63. Since the dielectric film 60 partially reflects the 1550-nm laser, the laser oscillates back and forth through the dielectric film 60 and the semiconductor saturable absorber mirror 63, and part of the light is output to the outside of the first resonator 6 and the second resonator 7 through the dielectric film 60, and finally output through the signal terminal 43 of the first wavelength division multiplexer 4 and the signal terminal 53 of the second wavelength division multiplexer 5 respectively. And because the semiconductor saturable absorber mirror 63 has high absorption for low-intensity light and high transmission for high-intensity light, during the back-and-forth oscillation of the laser, the pulse width gradually decreases, and finally pulse mode locking is achieved. Since the fiber parts of the first resonator 6 and the second resonator 7 are closely arranged at the same position, mechanical sharing of environmental noise can be realized to obtain a relatively stable dual optical comb output. In addition, since the lengths of the fiber parts of the first resonator 6 and the second resonator 7 are adjustable, asynchronous pulses with different repetition frequencies can be realized by controlling the lengths of the fibers. In some embodiments of the present invention, the total cavity lengths of the mechanically shared first resonator 6 and second resonator 7 can be flexibly controlled in the range of centimeters to meters, and the repetition frequency is in the range of 100 MHz to GHz.

[0040] Thus, the high-repetition-frequency crosstalk-free dual-comb fiber laser based on mechanical sharing according to the embodiments of the present invention can achieve good self-starting mode-locking ability by adjusting the power of the pump source 1. Since the first resonator 6 and the second resonator 7 are independent of each other, there is no crosstalk and mode competition problem between asynchronous pulses in the cavity. Therefore, a dual-comb output with high signal-to-noise ratio and high repetition frequency can be obtained. The cavity lengths of the first resonator 6 and the second resonator 7 respectively determine the repetition frequencies of the pulses output by each of them. Therefore, the repetition frequency difference between asynchronous pulses can be controlled by the length difference between the two resonators. In addition, the radio frequency signal generated by dual-comb beating can be adjusted by adjusting the adjustable optical attenuator to adjust the position of the radio frequency signal in the radio frequency domain, which can avoid spectral aliasing when the signal is close to the Nyquist sideband and affect the measurement results of dual-comb applications. The fiber parts of the first resonator 6 and the second resonator 7 are closely arranged at the same position, obtaining good environmental noise sharing ability, so that asynchronous pulses can obtain good relative stability without an additional servo system.

[0041] According to an embodiment of the present invention, the first doped fiber 61 and the second doped fiber 71, the first single-mode fiber 62 and the second single-mode fiber 72 achieve mechanical sharing of the first resonator 6 and the second resonator 7 by means of gluing. It should be noted that it is not limited to the gluing method, and a method similar to gluing can also be used, as long as the two resonators are closely combined to share environmental disturbances.

[0042] According to another embodiment of the present invention, the first doped fiber 61 and the second doped fiber 71, the first single-mode fiber 62 and the second single-mode fiber 72 achieve mechanical sharing of the first resonator 6 and the second resonator 7 in the form of a multi-core fiber.

[0043] In some embodiments of the present invention, the models of the first doped fiber 61 and the second doped fiber 71 are Er80-8 / 125, and the models of the first single-mode fiber 62 and the second single-mode fiber 72 are SMF-28e.

[0044] According to an embodiment of the present invention, the semiconductor saturable absorber mirror 63 is directly coupled to the multi-core fiber end faces of the first single-mode fiber 62 and the second single-mode fiber 72 respectively. Since the first resonator 6 and the second resonator 7 share a semiconductor saturable absorber mirror 63, they have similar mode-locking pulse characteristics.

[0045] According to an embodiment of the present invention, the light spots of the first resonator 6 and the light spots of the second resonator 7 are spatially separated on the semiconductor saturable absorber mirror 63. Thus, the pulse crosstalk problem caused by sharing an absorber can be avoided.

[0046] According to an embodiment of the present invention, the first doped optical fiber and the second doped optical fiber are high-gain optical fibers, and their absorption coefficient exceeds 80 dB / m at 1530 nm, which can ensure sufficient gain when shortening the length of the optical fiber in the cavity and realize mode-locked pulses with a high repetition frequency.

[0047] According to an embodiment of the present invention, the dielectric film 60 is formed by covering the end face of the optical fiber sleeve with a multi-layer SiO2 / Ta2O5 dielectric film 60 through a plasma sputtering deposition system. The dielectric film 60 serves as a dichroic mirror, which is completely transparent to the pump light and partially reflects the resonant laser wavelength. The dielectric film 60 has a transmittance as high as 97% for the 980 nm pump light and a reflectance of 83% for the light with a wavelength of about 1550 nm.

[0048] According to an embodiment of the present invention, the pump source 1 divides the pump light into two parts through the optical coupler 2. One part enters the first wavelength division multiplexer 4 after passing through the tunable optical attenuator 3, and the other part directly enters the second wavelength division multiplexer 5. The common ends of the first wavelength division multiplexer 4 and the second wavelength division multiplexer 5 are packaged into a multi-core fiber-like structure. The input end 42 of the first wavelength division multiplexer 4 is fiber-coupled with the first doped optical fiber 61 for coupling the pump light into the first resonant cavity 6; the input end 52 of the second wavelength division multiplexer 5 is fiber-coupled with the second doped optical fiber 71 for coupling the pump light into the second resonant cavity 7.

[0049] According to an embodiment of the present invention, the optical coupler 2 is a 1×2 coupler, and the end with a high splitting ratio is used as the second port 22 of the optical coupler 2, which is connected to the input end of the tunable optical attenuator 3.

[0050] Exemplarily, the optical coupler 2 is a 1×2 coupler with a splitting ratio of 70 / 30. The second port 22 corresponds to a splitting ratio of 70%, and the third port 23 corresponds to a splitting ratio of 30%.

[0051] According to an embodiment of the present invention, the multi-core fiber-like structure is formed by encapsulating two corresponding optical fibers in the same ceramic ferrule; or directly using a multi-core optical fiber for flange coupling. Among them, the multi-core fiber-like structure is as Figure 2 shown.

[0052] According to an embodiment of the present invention, the operating wavelengths of the first wavelength division multiplexer 4 and the second wavelength division multiplexer 5 are 980 / 1550 nm.

[0053] According to an embodiment of the present invention, the pump source 1 is a semiconductor laser coupled with a single-mode optical fiber, and the central wavelength is 980 nm. The first resonant cavity 6 and the second resonant cavity 7 sharing the same pump source 1 mechanically can achieve a better common-mode noise suppression ratio.

[0054] In summary, the high-repetition-frequency crosstalk-free dual optical frequency comb laser based on mechanical sharing according to the embodiments of the present invention can obtain dual optical frequency comb outputs without crosstalk problems and with higher repetition frequencies, which is beneficial to subsequent measurement applications.

[0055] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0056] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0057] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "connected to", "fixed" etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing, characterized in that: include: A pump source, the pump source is used to emit pump light; An optical coupler, a first port of the optical coupler being connected to the pump source; A tunable optical attenuator, wherein an input end of the tunable optical attenuator is connected to the second port of the optical coupler; A first wavelength division multiplexer, wherein a pump end of the first wavelength division multiplexer is connected to an output end of the tunable optical attenuator; a second wavelength division multiplexer, wherein a pump end of the second wavelength division multiplexer is connected to a third port of the optical coupler; A first resonant cavity, the first resonant cavity comprising a dielectric film, a first doped optical fiber, a first single-mode optical fiber and a semiconductor saturable absorber mirror connected in sequence, the first doped optical fiber being connected to a common end of the first wavelength division multiplexer; a second resonant cavity, the second resonant cavity comprising the dielectric film, the second doped optical fiber, the second single-mode optical fiber and the semiconductor saturable absorber mirror connected in sequence, the second doped optical fiber being connected to a common end of the second wavelength division multiplexer; The first doped optical fiber and the second doped optical fiber are packaged into a multi-core optical fiber structure to share a pump source; the first single-mode optical fiber and the second single-mode optical fiber are packaged into a multi-core optical fiber structure to share a semiconductor saturable absorber mirror; the optical fiber part of the first resonant cavity and the optical fiber part of the second resonant cavity are closely arranged in the same position to achieve mechanical sharing, wherein the lengths of the optical fiber part of the first resonant cavity and the optical fiber part of the second resonant cavity are adjustable.

2. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The first doped optical fiber and the second doped optical fiber, the first single-mode optical fiber and the second single-mode optical fiber are glued to achieve mechanical sharing of the first resonant cavity and the second resonant cavity.

3. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The first doped optical fiber and the second doped optical fiber, the first single-mode optical fiber and the second single-mode optical fiber realize mechanical sharing of the first resonant cavity and the second resonant cavity in a direct multi-core optical fiber manner.

4. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The semiconductor saturable absorber mirror is directly coupled to the multi-core optical fiber end faces of the first single-mode optical fiber and the second single-mode optical fiber respectively.

5. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The light spot of the first resonant cavity is spatially separated from the light spot of the second resonant cavity in the semiconductor saturable absorber mirror, thereby avoiding pulse crosstalk.

6. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The first doped optical fiber and the second doped optical fiber are high-gain optical fibers, and their absorption coefficient exceeds 80dB / m at 1530nm, which can ensure sufficient gain when shortening the length of the optical fiber in the cavity and realize high repetition frequency mode-locked pulses.

7. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The dielectric film is formed by covering the end face of the optical fiber sleeve with a multilayer SiO2 / Ta2O5 dielectric film through a plasma sputtering deposition system. The dielectric film acts as a dichroic mirror, completely transmitting the pump light and partially reflecting the resonant laser wavelength.

8. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The pump source divides the pump light into two parts through the optical coupler, one part enters the pump end of the first wavelength division multiplexer after passing through the tunable optical attenuator, and the other part directly enters the pump end of the second wavelength division multiplexer, the common end of the first wavelength division multiplexer and the common end of the second wavelength division multiplexer are packaged into a multi-core optical fiber structure, and the common end of the first wavelength division multiplexer is optically coupled with the first doped optical fiber to couple the pump light into the first resonant cavity; The common end of the second wavelength division multiplexer is fiber-coupled with the second doped optical fiber to couple the pump light into the second resonant cavity.

9. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The optical coupler is a 1×2 coupler, and one end with a high splitting ratio serves as the second port of the optical coupler and is connected to the input end of the tunable optical attenuator.

10. The high repetition rate crosstalk-free dual-comb fiber laser based on mechanical sharing according to claim 1, characterized in that: The multi-core optical fiber structure is formed by encapsulating two corresponding optical fibers in the same ceramic ferrule; or directly using multi-core optical fibers for flange coupling.

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