A typewriter and character conversion method based on bidirectionally mode-locked fiber laser pulse sequence graphics

Abstract

The present invention relates to a typewriter and character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence pattern. The system comprises a signal output module, a photodetector, an oscilloscope, and a computer-side signal processor. The signal output module is used to generate basic mode-locked pulse signals, including clockwise and counterclockwise bidirectional mode-locked signals, and modulates the mode-locked pulse signals in the time domain before outputting them. The photodetector is used to convert optical pulses from optical signals into electrical signals for output. The oscilloscope is used to receive the electrical signals output by the photodetector after conversion, display the pattern of the optical pulses in the time domain, and convert the signals into a data format. The computer-side signal processor receives the data output by the oscilloscope and, after system processing, outputs a combined character. This invention is the first to use a bidirectionally mode-locked fiber laser as a character output system. The typewriter is constructed in a parallel structure, adopting an all-fiber structure that does not require external signal modulation. It has the characteristics of simple structure, small size, and easy operation.

Description

Technical Field

[0001] The present invention relates to the field of laser communication technology, and in particular to a typewriter and a character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence graph. Background Art

[0002] Bidirectionally mode-locked fiber lasers, characterized by high stability and multi-soliton states, have attracted increasing attention from scholars and research teams in recent years. Compared to unidirectional optical cavities with optical isolators inserted within the resonant cavity, bidirectionally mode-locked fiber lasers utilize single-mode fiber instead of the isolators within the cavity. The pump signal oscillates bidirectionally within the cavity, generating reverse-phase optical pulses. This achieves optical path multiplexing and increases the complexity of the optical pulse output signal, offering numerous potential applications in laser communications.

[0003] Traditional bidirectionally mode-locked fiber lasers can only output soliton pulses in the clockwise (CW) and counterclockwise (CCW) directions. The complexity of the pulse sequence that can be displayed on an oscilloscope is limited, which to some extent limits the application of bidirectionally mode-locked fiber lasers in the field of optical communications. Summary of the Invention

[0004] In response to the above-mentioned improvement needs in the prior art, the present invention provides a typewriter and character conversion method based on a bidirectionally mode-locked fiber laser pulse train pattern. The purpose of the present invention is to build on the existing bidirectional pulse output characteristics of conventional bidirectionally mode-locked fiber lasers by using an optical coupler to split the CCW light pulse output from the cavity into two light pulses and perform time-domain modulation. The optical coupler is then used to combine the two CCW light pulses with the CW light pulse into one light pulse, thereby providing a typewriter and character conversion method based on a bidirectionally mode-locked fiber laser pulse train pattern.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A typewriter based on a bidirectionally mode-locked fiber laser pulse sequence pattern, comprising: a signal output module, a photodetector, an oscilloscope, and a computer-side signal processor;

[0007] The signal output module is used to generate a basic mode-locked pulse signal, including clockwise and counterclockwise mode-locked signals, and modulate the mode-locked pulse signal in the time domain before outputting it;

[0008] The photoelectric detector is used to convert the light pulse from an optical signal into an electrical signal for output;

[0009] The oscilloscope is used to receive the electrical signal output after conversion by the photodetector, display the graph of the light pulse in the time domain, and convert the signal into a data format;

[0010] The computer-side signal processor receives the data output by the oscilloscope and outputs the combined characters after system processing;

[0011] Preferably, the signal output module comprises: a plurality of bidirectionally mode-locked fiber lasers in a parallel structure, wherein the bidirectionally mode-locked fiber laser comprises: a laser diode pump source, a wavelength division multiplexer, a gain fiber, a polarization controller, a 2×2 optical coupler, a saturable absorber, a first polarization-independent isolator, a second polarization-independent isolator, a first optical coupler, a first time delay modulator, a second time delay modulator, a second optical coupler, and a third optical coupler;

[0012] The laser diode pump source is connected to the first port of the wavelength division multiplexer; the third port of the wavelength division multiplexer is connected to the gain fiber; the gain fiber is connected to the polarization controller; the polarization controller is connected to the first port of the 2×2 optical coupler, and the second port of the 2×2 optical coupler is connected to the saturable absorber; the saturable absorber is connected to the second port of the wavelength division multiplexer; the third port of the 2×2 optical coupler is connected to the first polarization-independent isolator; the first polarization-independent isolator is connected to the first port of the third optical coupler; the fourth port of the 2×2 optical coupler is connected to the second polarization-independent isolator of the clockwise modulation optical path unit; the second polarization-independent isolator is connected to the first port of the first optical coupler; the second port of the first optical coupler is connected to the first time delay modulator; the third port of the first optical coupler is connected to the second time delay modulator; the first time delay modulator is connected to the first port of the second optical coupler; the second time delay modulator is connected to the second port of the second optical coupler; the third port of the second optical coupler is connected to the second port of the third optical coupler;

[0013] Preferably, the gain fiber is an erbium-doped gain fiber;

[0014] Preferably, the saturable absorber is a carbon nanotube film;

[0015] The polarization controller is used to adjust the optical fiber birefringence effect and the polarization state of the intracavity light beam, so as to achieve a balance between the intracavity dispersion and the nonlinear effect to generate an initial mode-locked pulse signal.

[0016] The first time delay modulator and the second time delay modulator are both length-adjustable single-mode optical fibers;

[0017] The first time delay modulator and the second time delay modulator are used to modulate the relative delay of the CW direction pulse signal and the CCW direction needle pulse signal in the time domain.

[0018] The photodetector is connected to the third port of the third optical coupler; the oscilloscope is connected to the photodetector;

[0019] The photodetector is used to convert the received optical signal into an electrical signal and output it to the oscilloscope;

[0020] The oscilloscope is used to observe and record the graph of the pulse signal, and convert the received electrical signal into a data format and transmit it to the computer-side signal processor;

[0021] The computer-side signal processor is connected to the oscilloscope;

[0022] The computer-side signal processor is used to receive the data file transmitted by the oscilloscope, and convert the corresponding signal data into character output after system processing.

[0023] A character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence pattern, applicable to a typewriter based on a bidirectionally mode-locked fiber laser pulse sequence pattern, comprising:

[0024] Outputting a multi-channel combined pulse signal after time domain modulation through a signal output module;

[0025] The multi-channel combined pulse signal is used as the information carrier to be converted into an electrical signal through a photoelectric detector and output to an oscilloscope;

[0026] The oscilloscope reads the pulse intensity amplitude of the multi-channel combined pulse signal and records the signal, converts the signal into data and transmits it to the computer-side signal processor;

[0027] The computer-side signal processor analyzes and processes the multi-channel combined pulse signal, distinguishes the main pulse and the auxiliary pulse according to the intensity amplitude of the pulse sequence graph, and uses the relative time delay of the main and auxiliary pulses in the time domain to encode the character information.

[0028] Preferably, the outputting of the multi-channel combined pulse signal after time domain modulation through the signal output module specifically includes:

[0029] By modulating the pigtail lengths of the first and second delay modulators of each bidirectionally mode-locked fiber laser, the time delay length of the pulse signals of the two light paths split in the CCW direction relative to the pulse signal in the CW direction is modulated, and the combined pulse signal is output through the third optical coupler.

[0030] Preferably, the computer-side signal processor analyzes the processed multi-channel combined pulse signal and distinguishes the main pulse and the auxiliary pulse according to the intensity amplitude of the pulse sequence graph, and uses the relative time delay of the main pulse and the auxiliary pulse in the time domain to encode the character information, specifically including:

[0031] The computer-side signal processor normalizes the processed multi-channel combined pulse signals;

[0032] The signal greater than or equal to the first threshold (0.9) is converted into a corresponding one-grid main scale, and the signal greater than or equal to the second threshold (0.2) is converted into two-grid secondary scale;

[0033] According to the character conversion rule, the processed scale graphic is determined as the corresponding combined character information.

[0034] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0035] 1. The typewriter based on a bidirectionally mode-locked fiber laser provided by the present invention consists of a complete system consisting of a signal output module, a photodetector, an oscilloscope, and a computer-side signal processor. The signal output module is composed of multiple bidirectionally mode-locked fiber lasers connected in parallel. Each bidirectionally mode-locked fiber laser generates a basic mode-locked signal, including clockwise and counterclockwise bidirectional mode-locked signals. The mode-locked pulse signal is modulated in the time domain and then output. The relative delay between the CW direction pulse signal and the CCW direction pulse signal in the time domain can be controllably adjusted to generate a main pulse and two distinguishable secondary pulses. Finally, the computer-side signal processor receives the output information converted into a data format by the oscilloscope and outputs the characters after system processing.

[0036] 2. The signal transmission module of the present invention is composed of an all-fiber laser. The entire laser resonant cavity is formed into a whole by optical fiber fusion splicing, and the signal output system of the entire typewriter is formed by simply connecting multiple bidirectionally mode-locked fiber lasers in parallel. It does not require any external devices, has good stability and low cost.

[0037] 3. The time delay modulators in the signal transmission module are all single-mode optical fibers, which are low-cost and easy to operate.

[0038] 4. Bidirectional transmission, flexible and multi-purpose. As a multifunctional multiplexing laser, bidirectionally mode-locked fiber laser has many potential applications in the field of optical fiber communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a complete structural diagram of a typewriter based on a bidirectionally mode-locked fiber laser pulse sequence pattern in a preferred embodiment of the present invention.

[0040] Figure 2 The diagram is a complete structural diagram of a typewriter signal output module based on a bidirectionally mode-locked fiber laser pulse sequence pattern in a preferred embodiment of the present invention.

[0041] Figure 3 It is a flowchart of a character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence pattern in a specific example.

[0042] Figure 4 It is a schematic diagram of the computer-side signal processor interface display in a specific example.

[0043] Throughout the drawings, the same reference numbers are used to refer to the same elements or structures. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0045] The terms "first", "second", "third" and the like in the description and claims of the present invention are used to distinguish different objects rather than to describe a specific order.

[0046] like Figure 1 The figure shows a complete structural diagram of a typewriter based on a bidirectionally mode-locked fiber laser pulse sequence diagram provided by an embodiment of the present invention, including: a signal output module 1, a photodetector 2, an oscilloscope 3 and a computer-side signal processor 4.

[0047] The signal output module 1 includes multiple parallel bidirectional mode-locked fiber lasers, each of which is used to generate a basic mode-locked signal, including clockwise and counterclockwise bidirectional mode-locked signals, and modulate the mode-locked signals in the two directions in the time domain to output a combined pulse signal.

[0048] The photodetector 2 is used to convert the light pulse from an optical signal into an electrical signal for output.

[0049] The oscilloscope 3 is used to receive the electrical signal output after conversion by the photodetector, display the graph of the light pulse in the time domain, and convert the signal into a data format.

[0050] The computer-side signal processor 4 receives the data converted by the oscilloscope 3 and outputs the data as characters after system processing.

[0051] like Figure 2 A schematic diagram of the complete structure of a signal output module provided in an embodiment of the present invention includes: multiple parallel bidirectionally mode-locked fiber lasers 5, each of which includes: a laser diode pump source 6, a wavelength division multiplexer 7, a gain fiber 8, a polarization controller 9, a 2×2 optical coupler 10, a saturable absorber 11, a first polarization-independent isolator 12, a second polarization-independent isolator 13, a first optical coupler 14, a first delay modulator 15, a second delay modulator 16, a second optical coupler 17, and a third optical coupler 18.

[0052] The laser diode pump source 6 is connected to the first port 7a of the wavelength division multiplexer 7; the third port 7c of the wavelength division multiplexer 7 is connected to the gain fiber 8; the gain fiber 8 is connected to the polarization controller 9; the polarization controller 9 is connected to the first port 10a of the 2×2 optical coupler 10, and the second port 10b of the 2×2 optical coupler 10 is connected to the saturable absorber 11; the saturable absorber 11 is connected to the second port 7b of the wavelength division multiplexer 7; the third port 10c of the 2×2 optical coupler 10 is connected to the first polarization-independent isolator 12; the first polarization-independent isolator 12 is connected to the first port 18a of the third optical coupler 18 connection; the fourth port 10d of the 2×2 optical coupler 10 is connected to the second polarization-independent isolator 13; the second polarization-independent isolator 13 is connected to the first port 14a of the first optical coupler 14; the second port 14b of the first optical coupler 14 is connected to the first time delay modulator 15; the third port 14c of the first optical coupler 14 is connected to the second time delay modulator 16; the first time delay modulator 15 is connected to the first port 17a of the second optical coupler 17; the second time delay modulator 16 is connected to the second port 17b of the second optical coupler 17; the third port 17c of the second optical coupler 17 is connected to the second port 18b of the third optical coupler 18.

[0053] The gain fiber 4 is a low-doped erbium-doped fiber, which is used to absorb the pump light energy and provide gain for the laser pulse through the stimulated emission light amplification effect.

[0054] The polarization controller 5 is used to adjust the optical fiber birefringence effect and the polarization state of the intracavity light beam so as to achieve a balance between the intracavity dispersion and the nonlinear effect to generate an initial mode-locked pulse signal.

[0055] The saturable absorber 7 is made of a carbon nanotube film, which is used to achieve bidirectional and simultaneous laser pulse mode-locking operation. It has nonlinear saturable absorption properties and can introduce a mode-locking mechanism into the laser, thereby outputting the laser pulses required by the present invention.

[0056] The first delay modulator 15 and the second delay modulator 16 are both length-adjustable single-mode optical fibers, which are used to modulate the relative delay of the clockwise pulse signal and the counterclockwise pulse signal in the time domain. By modulating the length of the single-mode optical fiber, the corresponding delay modulation of the mode-locked pulse can be performed in the time domain.

[0057] like Figure 3 The figure shows a flow chart of a character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence pattern provided by the present invention, comprising:

[0058] 19. Each of the parallel bidirectional mode-locked fiber lasers 5 modulates the relative delay of the two pulse signals split in the CCW direction relative to the CW direction pulse signal through the first delay modulator 15 and the second delay modulator 16, thereby generating a modulated bidirectional mode-locked combined soliton pulse with controllable relative delay in the time domain.

[0059] 19 specifically includes: by changing the first delay modulator 15 and the second delay modulator 16 in the two optical paths of CCW beam splitting, the mode-locked pulses generated by the two CCW optical paths and the mode-locked pulses generated by the CW direction have a relative and controllable time delay in the time domain.

[0060] Schematic diagram of the pulse scaling principle (20).

[0061] The pulse scale principle diagram (20) specifically includes: defining the scale whose intensity amplitude exceeds the first threshold (0.9) as the main scale, and the main scale has a fixed repetition frequency. Ten sub-scales with equal spacing are divided between the two main scales in each cycle. The intensity amplitude of the sub-scales is above the second threshold (0.2) and below the first threshold (0.9). The five sub-scales on the left in the same cycle are defined as "sub-scale 1" and are defined as "1", "2", "3", "4", and "5" respectively; the five sub-scales on the right in the same cycle are defined as "sub-scale 2" and are defined as "1", "2", "3", "4", and "5" respectively. According to the above scale principle, a total of 25 permutations and combinations of sub-scales 1 and 2 can be obtained, which correspond one-to-one to the permutations and combinations of CCW1 direction pulses and CCW2 direction pulse sequences. The result of only the main scale existing without sub-scale 1 and sub-scale 2 is matched with the pulse sequence of turning off CCW direction pulse and only CW direction pulse existing. A total of 26 scale results can be obtained, corresponding to 26 pulse sequence patterns.

[0062] Character conversion rule 21 converts the relative time delay in the time domain between the mode-locked pulse generated by the CW direction optical path unit and the mode-locked pulse generated by the CCW direction optical path from an optical signal into an electrical signal through the photodetector 2, and outputs it to the oscilloscope 3 to display a resolvable pulse sequence scale corresponding to the character conversion rule 21.

[0063] The character conversion rule 21 specifically includes: the oscilloscope 3 reads the combined pulse signal output by each bidirectional mode-locked fiber laser 5 connected in parallel in the signal output module 1, processes the combined pulse signal into a data file and transmits it to the computer-side data processor 4, the computer-side data processor 4 will distinguish the pulse signal into one main pulse and two auxiliary pulse signals according to the pulse intensity amplitude and perform normalization processing, convert the signal greater than or equal to the first threshold (0.9) into a corresponding one-grid main scale, and convert the signal greater than or equal to the second threshold (0.2) into two-grid auxiliary scales, the normalized signal is redrawn into a pulse sequence diagram and displayed on the interface, and the character information is determined according to the character conversion rule 21 and displayed on the interface together with the pulse sequence diagram.

[0064] like Figure 4 Shown is a schematic diagram of a specific embodiment.

[0065] As a specific embodiment, Figure 4 Shown is the pulse train of "MLFL," the abbreviation for "mode-locked fiber laser." Figure 4 It is a display interface of a computer-side signal processor, comprising: a first normalized pulse sequence diagram (22), a second normalized pulse sequence diagram (23), a third normalized pulse sequence diagram (24), a fourth normalized pulse sequence diagram (25), a first character output window 26, a second character output window 27, a third character output window 28, a fourth character output window 29, a start button 30 and a total coding output result 31.

[0066] Figure 4The first normalized pulse sequence diagram (22), the second normalized pulse sequence diagram (23), the third normalized pulse sequence diagram (24), and the fourth normalized pulse sequence diagram (25) show that the pulse sequence is divided into a main peak and two secondary peaks according to the intensity amplitude. When the normalized pulse intensity amplitude exceeds the first threshold value (0.9), it is determined to be the main peak, and the corresponding identifiable scale is the main scale. When the normalized pulse intensity amplitude exceeds the second threshold value (0.2), it is determined to be the secondary peak, and the corresponding identifiable scale is the secondary scale. The time delay of the secondary peak relative to the main peak shown in the normalized pulse sequence diagram can be directly automatically recognized as the corresponding scale by the computer-side signal processor 4 according to the character conversion rule 21. The length of the time delay corresponds to the size of the scale. Every time the time delay reaches 5ns, the system determines that the secondary scale is increased by one. The computer-side data encoding system automatically determines that the sub-scale corresponding to the time delay of the secondary peak relative to the main peak of the first normalized pulse sequence diagram (22) is "3-2", the sub-scale corresponding to the time delay of the secondary peak relative to the main peak of the second normalized pulse sequence diagram (23) is "3-1", the sub-scale corresponding to the time delay of the secondary peak relative to the main peak of the third normalized pulse sequence diagram (24) is "1-5", and the sub-scale corresponding to the time delay of the secondary peak relative to the main peak of the fourth normalized pulse sequence diagram (25) is "3-1". The corresponding first character is "M", the second character is "L", the third character is "F", and the fourth character is "L". Therefore, the result 31 jointly output by the multiple parallel bidirectional mode-locked fiber lasers 5 of the signal transmission module 1 of the typewriter is "MLFL".

[0067] Figure 4 The first normalized pulse sequence diagram (22), the second normalized pulse sequence diagram (23), the third normalized pulse sequence diagram (24) and the fourth normalized pulse sequence diagram (25) all show interference peaks in addition to one main peak and two secondary peaks. Interference peaks are unavoidable and can be directly eliminated through system functions, thus having no effect on the recognition results.

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0069] It will be easily understood by those skilled in the art that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A typewriter based on a bidirectionally mode-locked fiber laser pulse train pattern, characterized in that: include: Signal output module 1, photoelectric detector 2, oscilloscope 3 and computer-side signal processor 4, wherein, The signal output module 1 is connected to the photodetector 2; the photodetector 2 is connected to the oscilloscope 3; the oscilloscope 3 is connected to the computer-side signal processor 4; The signal output module 1 includes a plurality of bidirectional mode-locked fiber lasers 5 connected in parallel, each of which is used to generate a basic mode-locked signal, including a clockwise and counterclockwise bidirectional mode-locked signal; The photodetector 2 is used to convert the light pulse from an optical signal into an electrical signal for output; The oscilloscope 3 is used to receive the electrical signal output by the photodetector after conversion, display the graph of the light pulse in the time domain, and convert the signal into a data format. The computer-side signal processor 4 receives the data output by the oscilloscope and outputs the combined characters after system processing.

2. A typewriter based on a bidirectionally mode-locked fiber laser pulse train pattern according to claim 1, characterized in that: The signal output module 1 includes a plurality of bidirectionally mode-locked fiber lasers 5 connected in parallel, and the bidirectionally mode-locked fiber laser 5 includes: a laser diode pump source 6, a wavelength division multiplexer 7, a gain fiber 8, a polarization controller 9, a 2×2 optical coupler 10, a saturable absorber 11, a first polarization-independent isolator 12, a second polarization-independent isolator 13, a first optical coupler 14, a first delay modulator 15, a second delay modulator 16, a second optical coupler 17 and a third optical coupler 18. The laser diode pump source 6 is connected to the first port 7a of the wavelength division multiplexer 7; the third port 7c of the wavelength division multiplexer 7 is connected to the gain fiber 8; the gain fiber 8 is connected to the polarization controller 9; the polarization controller 9 is connected to the first port 10a of the 2×2 optical coupler 10, and the second port 10b of the 2×2 optical coupler 10 is connected to the saturable absorber 11; the saturable absorber 11 is connected to the second port 7b of the wavelength division multiplexer 7; the third port 10c of the 2×2 optical coupler 10 is connected to the first polarization-independent isolator 12; the first polarization-independent isolator 12 is connected to the first port 18a of the third optical coupler 18; the 2×2 optical The fourth port 10d of the coupler 10 is connected to the second polarization-independent isolator 13; the second polarization-independent isolator 13 is connected to the first port 14a of the first optical coupler 14; the second port 14b of the first optical coupler 14 is connected to the first time delay modulator 15; the third port 14c of the first optical coupler 14 is connected to the second time delay modulator 16; the first time delay modulator 15 is connected to the first port 17a of the second optical coupler 17; the second time delay modulator 16 is connected to the second port 17b of the second optical coupler 17; the third port 17c of the second optical coupler 17 is connected to the second port 18b of the third optical coupler 18. The saturable absorber 7 is a carbon nanotube film having nonlinear saturable absorption properties and can introduce a mode-locking mechanism into the laser.

3. A typewriter based on a bidirectionally mode-locked fiber laser pulse train pattern according to claim 2, characterized in that: The first time delay modulator 15 and the second time delay modulator 16 are both length-adjustable single-mode optical fibers.

4. A character conversion method based on a bidirectionally mode-locked fiber laser pulse train pattern, applicable to a typewriter based on a bidirectionally mode-locked fiber laser pulse train pattern according to any one of claims 1 to 3, characterized in that: include: Outputting a multi-channel combined pulse signal after time domain modulation through a signal output module; The multi-channel combined pulse signal is used as the information carrier to be converted into an electrical signal through a photoelectric detector and output to an oscilloscope; The oscilloscope reads the pulse intensity amplitude of the multi-channel combined pulse signal and records the signal, converts the signal into data and transmits it to the computer-side signal processor; The computer-side signal processor analyzes and processes the multi-channel combined pulse signal, distinguishes the main pulse and the auxiliary pulse according to the intensity amplitude of the pulse sequence graph, and encodes it into character information according to the character conversion rules.

5. The character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence pattern according to claim 4, characterized in that: The outputting of the multi-channel combined pulse signal after time domain modulation through the signal output module specifically includes: By modulating the pigtail lengths of the first and second delay modulators of each bidirectionally mode-locked fiber laser, the time delay length of the pulse signals of the two optical paths split in the CCW direction relative to the pulse signals in the CW direction is modulated, and the combined pulse signal is output through the third optical coupler.

6. The character conversion method based on a bidirectionally mode-locked fiber laser pulse sequence pattern according to claim 4, characterized in that: The computer-side signal processor analyzes and processes the multi-channel combined pulse signal, distinguishes the main pulse from the auxiliary pulse according to the intensity amplitude of the pulse sequence graph, and encodes the relative time delay of the main pulse and the auxiliary pulse into character information, specifically including: The computer-side signal processor normalizes the processed multi-channel combined pulse signals; The signal greater than or equal to the first threshold (0.9) is converted into a corresponding one-grid main scale, and the signal greater than or equal to the second threshold (0.2) is converted into two-grid secondary scale; According to the character conversion rule, the processed scale graphic is determined as the corresponding combined character information.

Images