Human eye safe wave band fiber laser
By introducing amplification components of pumped lasers, erbium-ytterbium co-doped double-clad fibers and beam combiners into human eye safety band fiber lasers, the problem of insufficient power of existing lasers is solved, and a higher power laser output is achieved to meet the needs of precision machining.
Patent Information
- Application Number
- CN202411797429.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-07
AI Technical Summary
The laser power generated by existing human eye safety band fiber lasers is generally low, which is difficult to meet the needs of laser precision processing.
The laser power is amplified by using at least one-stage amplification assembly including a pump laser, an erbium-ytterbium co-doped double-clad fiber and a beam combiner.
By increasing laser power, more diverse and applicable needs are met, especially in the field of precision machining.
Smart Images
Figure CN119581976A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of optical fiber lasers, and more specifically, relates to an optical fiber laser in an eye-safe band. Background Art
[0002] Lasers with a wavelength of 1550nm are in the eye-safe band, which is not likely to cause damage to the human eye and can be widely used in many fields. The laser power generated by existing fiber lasers in the eye-safe band is generally low, which is difficult to meet the needs of laser precision processing. Summary of the invention
[0003] The purpose of the embodiments of the present application is to provide an eye-safe band fiber laser to solve the technical problem in the prior art that the laser power generated by the existing eye-safe band fiber lasers is generally low.
[0004] To achieve the above purpose, the technical solution adopted in this application is: to provide an eye-safe fiber laser, the eye-safe fiber laser comprising:
[0005] Laser seed source; the central wavelength of the laser seed source is 1550nm;
[0006] At least one stage of amplification component; the amplification component includes a pump laser, an erbium-ytterbium co-doped double-clad optical fiber and a beam combiner, the laser seed source is connected to the erbium-ytterbium co-doped double-clad optical fiber, and the pump laser is connected to the erbium-ytterbium co-doped double-clad optical fiber through the beam combiner.
[0007] Optionally, the laser seed source includes a tunable pulse fiber laser, the line width of the tunable pulse fiber laser is less than 5nm, the output fiber is a 10 / 125 double-clad fiber, the output state is pulsed, the peak power is greater than 4W, the pulse width range is 10-1000ns, and the repetition frequency is 1-4000kHz.
[0008] Optionally, the eye-safe band fiber laser further includes a first online isolator, which is connected between the laser seed source and the amplification component;
[0009] The first online isolator has a central wavelength of 1550nm, an operating bandwidth of 10nm, an input fiber of 10 / 125 double-clad fiber, an output fiber of 10 / 125 double-clad fiber, an average power of 300mW, an insertion loss of less than 1dB, and an isolation greater than 25dB.
[0010] Optionally, the amplification component includes a first-stage amplification component, which includes a first pump laser, a first erbium-ytterbium co-doped double-clad optical fiber and a first beam combiner;
[0011] The signal end of the first beam combiner is connected to the laser seed source, the pump end of the first beam combiner is connected to the first pump laser, and the output end of the first beam combiner is connected to the first erbium-ytterbium co-doped double-clad optical fiber, so that the first pump laser provides pump excitation to the first erbium-ytterbium co-doped double-clad optical fiber;
[0012] The central wavelength of the first pump laser is 976±5nm, the output power is greater than 10W, the central wavelength is 976nm±5nm, and the output optical fiber is 105 / 125 multimode optical fiber; the first erbium-ytterbium co-doped double-clad optical fiber is erbium-ytterbium co-doped 10 / 125 double-clad optical fiber.
[0013] Optionally, the optical fiber at the signal end of the first combiner is a 10 / 125 double-clad optical fiber, the optical fiber at the pump end is a 105 / 125 multimode optical fiber, the pump light coupling efficiency is greater than 95%, the signal light withstand power is greater than 3W, and the pump light withstand power is greater than 10W.
[0014] Optionally, the amplification component further includes a secondary amplification component, which includes a second pump laser, a second erbium-ytterbium co-doped double-clad optical fiber, and a second combiner;
[0015] The second erbium-ytterbium co-doped double-clad optical fiber is connected to the first-stage amplification component, the pump end of the second beam combiner is connected to the second pump laser, and the output end of the second beam combiner is connected to the second erbium-ytterbium co-doped double-clad optical fiber, so that the second pump laser provides pump excitation to the second erbium-ytterbium co-doped double-clad optical fiber, and the signal end of the second beam combiner serves as the output end of the second-stage amplification component;
[0016] The central wavelength of the second pump laser is 976±5nm, the output power is greater than 20W, the central wavelength is 976nm±5nm, and the output fiber is 105 / 125 multimode fiber; the second erbium-ytterbium co-doped double-clad fiber is erbium-ytterbium co-doped 20 / 125 double-clad fiber.
[0017] Optionally, the optical fiber at the signal end of the second combiner is a 20 / 125 double-clad optical fiber, the optical fiber at the pump end is a 105 / 125 multimode optical fiber, the pump light coupling efficiency of the second combiner is greater than 95%, the signal light withstand power is greater than 10W, and the pump light withstand power is greater than 20W.
[0018] Optionally, the eye-safe band fiber laser also includes a second online isolator, which is connected between the primary amplification component and the secondary amplification component. The central wavelength of the second online isolator is 1550nm, the working bandwidth is 10nm, the input fiber is 10 / 125 double-clad fiber, the output fiber is 10 / 125 double-clad fiber, the average power it withstands is 3W, the insertion loss is less than 1dB, and the isolation is greater than 25dB.
[0019] Optionally, the eye-safe band fiber laser also includes a mode field adapter, which is connected between the second online isolator and the secondary amplification component, the input end of the mode field adapter is a 10 / 125 double-clad optical fiber, and the output end is a 20 / 125 double-clad optical fiber, and can withstand an average power greater than 3W.
[0020] Optionally, the eye-safe band fiber laser further includes an output isolator, and an input end of the output isolator is connected to a signal end of the second beam combiner;
[0021] The output isolator has an operating wavelength of 1550nm, and the input fiber is 20 / 125 double-clad fiber. It can withstand an average power greater than 10W, a peak power greater than 20kW, and an isolation greater than 25dB.
[0022] The beneficial effect of the eye-safe band fiber laser provided by the present application is that: compared with the prior art, the eye-safe band fiber laser in the embodiment of the present application includes and at least one stage of amplification component, the central wavelength of the laser seed source is 1550nm, the amplification component includes a pump laser, erbium-ytterbium co-doped double-clad fiber and a beam combiner, and the gain effect of the erbium-ytterbium co-doped double-clad fiber in the eye-safe band can be used to greatly improve the power of the eye-safe band fiber laser, so that it can meet more diverse application needs. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0024] Figure 1 Schematic diagram of an eye-safe fiber laser in an embodiment of the present application.
[0025] Among them, the reference numerals in the figure are:
[0026] Seed source component 1; tunable pulse fiber laser 11; first online isolator 12; first-stage amplification component 2; first pump laser 21; first combiner 22; first erbium-ytterbium co-doped double-clad fiber 23; second online isolator 24; second-stage amplification component 3; mode field adapter 31; second erbium-ytterbium co-doped double-clad fiber 32; second combiner 33; second pump laser 34; output isolator 41. DETAILED DESCRIPTION
[0027] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0028] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0029] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do 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 therefore should not be understood as a limitation on the present application.
[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0031] At present, the main method of generating pulsed lasers is to generate nanosecond and picosecond pulsed lasers through active Q-switching or passive Q-switching technology, which has disadvantages such as single output pulse width and limited tuning frequency range, and cannot meet the diversified application market needs. The pulsed lasers generated by directly modulating semiconductor laser diodes can achieve a large frequency tuning range, and the pulse width is tunable, which can meet the diversified application market needs. Among the existing single-mode semiconductor laser diodes on the market, only products in the 1064nm band can obtain a large average power, while lasers in the eye-safe band of 1550nm wavelength cannot achieve higher powers, which greatly limits their scope of use, especially in precision machining.
[0032] See also Figure 1 , the eye-safe fiber laser provided in the embodiment of the present application is now described. The eye-safe fiber laser includes:
[0033] Laser seed source; the central wavelength of the laser seed source is 1550nm;
[0034] At least one stage of amplification component; the amplification component includes a pump laser, an erbium-ytterbium co-doped double-clad optical fiber and a beam combiner, the laser seed source is connected to the erbium-ytterbium co-doped double-clad optical fiber, and the pump laser is connected to the erbium-ytterbium co-doped double-clad optical fiber through the beam combiner.
[0035] The central wavelength of the laser seed source of this embodiment is 1550nm. This wavelength is within the safe band of the human eye, which means that it has a low risk of harming the human eye. The laser seed source is the part that generates the initial laser signal, which will be amplified by the subsequent amplification component to achieve a higher power.
[0036] The eye-safe fiber laser of this embodiment may include one or more amplification components to achieve higher output power. The amplification component includes a pump laser, an erbium-ytterbium co-doped double-clad fiber and a beam combiner. The pump laser is responsible for providing energy to excite the erbium-ytterbium co-doped double-clad fiber, thereby amplifying the laser. In the erbium-ytterbium co-doped double-clad fiber, erbium ions and ytterbium ions are co-doped in the fiber, wherein the ytterbium ions can absorb the pump light of the pump laser and can effectively transfer energy to the erbium ions. After being excited, the erbium ions can transition from their low energy level to a high energy level, and then amplify the 1550nm laser under the action of the laser seed source when returning to the low energy level. The erbium ions have a strong gain characteristic near 1550nm, so the power of the eye-safe fiber laser can be effectively amplified.
[0037] In general, in this embodiment, the laser seed source generates an initial 1550nm laser signal, the pump laser generates pump light and injects it into the erbium-ytterbium co-doped double-clad optical fiber, the ytterbium ions absorb the energy of the pump light and transfer part of the energy to the erbium ions, and the erbium ions, after being excited, release 1550nm laser light with the same wavelength as the laser seed source. Due to the waveguide effect of the optical fiber, the laser signal is amplified in the optical fiber and transmitted along the optical fiber, thereby outputting high-power laser light, so that the 1550nm laser can be used in more fields, especially in the field of precision machining.
[0038] In some embodiments of the present application, the laser seed source includes a tunable pulse fiber laser 11, the line width of the tunable pulse fiber laser 11 is less than 5nm, the output fiber is a 10 / 125 double-clad fiber, the output state is pulsed, the peak power is greater than 4W, the pulse width range is 10-1000ns, and the repetition frequency is 1-4000kHz.
[0039] The tunable pulse fiber laser 11 can stabilize the wavelength of its output laser, thereby keeping the output center wavelength at 1550nm. At the same time, the tunable pulse fiber laser 11 can emit laser in pulse form rather than continuous wave form. The line width of the laser seed source of this embodiment is less than 5nm, which can ensure the stable output of 1550nm laser. The laser seed source of this embodiment outputs the laser signal in the form of pulses, and can accurately control the action time of the laser. Peak power refers to the maximum power reached by the laser pulse in a very short time. The peak power of the laser seed source of this embodiment is greater than 4W, and the laser can generate high-intensity laser pulses. Pulse width refers to the duration of the laser pulse. The pulse width range of the laser seed source of this embodiment is 10-1000ns, which can achieve nanosecond control. The repetition frequency refers to the number of times the laser generates laser pulses per second. The repetition frequency of the laser seed source of this embodiment is 1-4000kHz, so it can be adjusted between 1000-4000000 times per second. In summary, the laser seed source of this embodiment has the characteristics of stable central wavelength, high peak power, adjustable pulse width and repetition frequency, etc., which can provide a good foundation for amplifying laser power.
[0040] In some embodiments of the present application, the eye-safe band fiber laser also includes a first online isolator 12, which is connected between the laser seed source and the amplification component; the central wavelength of the first online isolator 12 is 1550nm, the working bandwidth is 10nm, the input fiber is 10 / 125 double-clad fiber, the output fiber is 10 / 125 double-clad fiber, the average power is 300mW, the insertion loss is less than 1dB, and the isolation is greater than 25dB.
[0041] An inline isolator is an optical device used to prevent optical signals from propagating in the opposite direction in an optical fiber system. This is essential for protecting lasers and amplifiers from being affected by reflected light. In this embodiment, the first inline isolator 12 is placed between the laser seed source and the amplification component to ensure unidirectional transmission of the laser signal and prevent any possible reflected light from damaging the laser seed source or affecting the amplification process.
[0042] The central wavelength of the online isolator refers to the wavelength of the laser signal that can be most effectively transmitted when the isolator is designed. The central wavelength of the first online isolator 12 is 1550nm, which is consistent with the central wavelength of the laser seed source. The working bandwidth refers to the wavelength range of the laser signal that the isolator can effectively transmit. When selecting an isolator, it should be ensured that the wavelength of the laser system is within the working bandwidth. The working bandwidth of the first online isolator 12 is 10nm, and the line width of the laser seed source is less than 5nm, which can ensure the effective transmission of the laser emitted by the laser seed source. The input fiber of the first online isolator 12 is a 10 / 125 double-clad fiber, and the output fiber is a 10 / 125 double-clad fiber. The average power is 300mW, which means that the maximum average input power that the first isolator can withstand is 300mW. Insertion loss refers to the power loss generated when the optical signal passes through the isolator. The insertion loss of the first online isolator 12 is less than 1dB, which means that there is only a small power loss when the optical signal passes through the isolator. Isolation refers to the ability of an isolator to prevent the propagation of a reverse optical signal. The isolation of the first online isolator 12 is greater than 25 dB, which can ensure effective isolation of the reverse optical signal.
[0043] In some embodiments of the present application, the amplification component includes a first-stage amplification component 2, which includes a first pump laser 21, a first erbium-ytterbium co-doped double-clad optical fiber 23 and a first combiner 22; the signal end of the first combiner 22 is connected to a laser seed source, the pump end of the first combiner 22 is connected to the first pump laser 21, and the output end of the first combiner 22 is connected to the first erbium-ytterbium co-doped double-clad optical fiber 23, so that the first pump laser 21 provides pump excitation to the first erbium-ytterbium co-doped double-clad optical fiber 23; the central wavelength of the first pump laser 21 is 976±5nm, the output power is greater than 10W, the central wavelength is 976nm±5nm, and the output optical fiber is a 105 / 125 multimode optical fiber; the first erbium-ytterbium co-doped double-clad optical fiber 23 is an erbium-ytterbium co-doped 10 / 125 double-clad optical fiber.
[0044] The first beam combiner 22 can combine the signal light from the laser seed source and the pump light from the first pump laser 21, and guide them to the first erbium-ytterbium co-doped double-clad optical fiber 23. During the amplification process, the initial laser signal generated by the laser seed source enters through the signal end of the first beam combiner 22. At the same time, the pump light generated by the first pump laser 21 enters through the pump end of the beam combiner. Inside the beam combiner, the signal light and the pump light are combined and guided to the first erbium-ytterbium co-doped double-clad optical fiber 23. In the optical fiber, the ytterbium ions act as sensitizers to transfer energy to the erbium ions, causing the erbium ions to transition to a high energy level. Subsequently, the erbium ions convert energy into signal light through stimulated radiation, thereby achieving amplification of the laser signal.
[0045] The output power of the first pump laser 21 is greater than 10W, which ensures sufficient pump energy to effectively excite the ions in the erbium-ytterbium co-doped fiber; the central wavelength is 976nm±5nm, and the pump light within this wavelength range can be efficiently absorbed by the erbium-ytterbium co-doped fiber; the output fiber is a 105 / 125 multimode fiber, which can meet the transmission requirements of the pump laser. The first erbium-ytterbium co-doped double-clad fiber 23 adopts a 10 / 125 double-clad design, with the inner layer as the core and the outer layer as the cladding. This structure contributes to the stable transmission of optical signals and the effective use of pump light. The length of the first erbium-ytterbium co-doped double-clad fiber 23 is determined according to the actual absorption coefficient of the optical fiber.
[0046] In some embodiments of the present application, the optical fiber at the signal end of the first combiner 22 is a 10 / 125 double-clad optical fiber, the optical fiber at the pump end is a 105 / 125 multimode optical fiber, the pump light coupling efficiency is greater than 95%, the signal light withstand power is greater than 3W, and the pump light withstand power is greater than 10W.
[0047] The optical fiber at the signal end of the first combiner 22 is a 10 / 125 double-clad optical fiber, which matches the output optical fiber of the laser seed source, and the optical fiber at the pump end is a 105 / 125 multimode optical fiber, which matches the output optical fiber of the first pump laser 21. The pump light coupling efficiency refers to the efficiency of the pump light entering the amplification component through the combiner after being output from the pump laser. The signal light withstand power refers to the maximum signal light power that the combiner can withstand without causing performance degradation or damage. The pump light withstand power refers to the maximum pump light power that the combiner can withstand. The pump light coupling efficiency of the first combiner 22 of this embodiment is greater than 95%, the signal light withstand power is greater than 3W, and the pump light withstand power is greater than 10W, which provides an efficient and stable signal light and pump light transmission channel for the laser amplification system.
[0048] In some embodiments of the present application, the amplification component also includes a secondary amplification component, which includes a second pump laser, a second erbium-ytterbium co-doped double-clad fiber, and a second combiner; the second erbium-ytterbium co-doped double-clad fiber is connected to the primary amplification component, the pump end of the second combiner is connected to the second pump laser, and the output end of the second combiner is connected to the second erbium-ytterbium co-doped double-clad fiber, so that the second pump laser provides pump excitation to the second erbium-ytterbium co-doped double-clad fiber, and the signal end of the second combiner serves as the output end of the secondary amplification component; the central wavelength of the second pump laser is 976±5nm, the output power is greater than 20W, the central wavelength is 976nm±5nm, and the output fiber is 105 / 125 multimode fiber; the second erbium-ytterbium co-doped double-clad fiber is an erbium-ytterbium co-doped 20 / 125 double-clad fiber.
[0049] The components in the secondary amplifier component 3 are similar to those in the primary amplifier component 2. The signal light after the primary amplification is transmitted to the second erbium-ytterbium co-doped double-clad optical fiber 32. At the same time, the pump light output by the second pump laser 34 also enters the optical fiber through the pump end of the second combiner 33. Inside the optical fiber, the ytterbium ions act as sensitizers to transfer energy to the erbium ions, causing them to transition from a low energy level to a high energy level. Subsequently, these high-energy-level ions quickly return to a low energy level when they come into contact with the signal light, and release a laser signal with the same wavelength as the signal light but a higher power. The signal end of the second combiner serves as the output end of the secondary amplifier component, which can ensure that the output signal light is purer and does not contain the components of the pump light. The central wavelength and output optical fiber of the second pump laser 34 are consistent with those of the first pump laser 21, but the output power of the second pump laser 34 is greater than 20W, which is higher than the output power of the first pump laser 21 in the primary amplifier component 2, so as to provide a stronger pump excitation. The second erbium-ytterbium co-doped double-clad optical fiber 32 adopts a 20 / 125 double-clad design. Compared with the 10 / 125 double-clad optical fiber in the first-stage amplifier component 2, the core diameter is larger and can accommodate higher optical power while maintaining stable transmission of optical signals. The length of the second erbium-ytterbium co-doped double-clad optical fiber 32 is determined according to the actual absorption coefficient of the optical fiber.
[0050] In some embodiments of the present application, the optical fiber at the signal end of the second combiner 33 is a 20 / 125 double-clad optical fiber, the optical fiber at the pump end is a 105 / 125 multimode optical fiber, the pump light coupling efficiency of the second combiner 33 is greater than 95%, the signal light withstand power is greater than 10W, and the pump light withstand power is greater than 20W.
[0051] The optical fiber at the signal end of the second combiner 33 is a 20 / 125 double-clad optical fiber that matches the second erbium-ytterbium co-doped double-clad optical fiber 32, and the optical fiber at the pump end is a 105 / 125 multimode optical fiber that matches the output optical fiber of the second pump laser 34. The pump light coupling efficiency is also greater than 95%, the signal light withstand power is greater than 10W to meet the laser requirements after amplification by the first-stage amplifier component 2, and the pump light withstand power is greater than 20W to meet the laser power requirements output by the second pump laser 34.
[0052] In some embodiments of the present application, the eye-safe band fiber laser also includes a second online isolator 24, which is connected between the first-stage amplification component 2 and the second-stage amplification component 3. The center wavelength of the second online isolator 24 is 1550nm, the working bandwidth is 10nm, the input fiber is 10 / 125 double-clad fiber, the output fiber is 10 / 125 double-clad fiber, the average power is 3W, the insertion loss is less than 1dB, and the isolation is greater than 25dB.
[0053] The second online isolator 24 is connected between the primary amplifying component 2 and the secondary amplifying component 3, and can prevent the reverse propagation of the laser after the primary amplifying component 2. Its parameters such as central wavelength, working bandwidth, input optical fiber, output optical fiber, insertion loss, isolation, etc. are similar to those of the first online isolator 12. However, the average power it withstands reaches 3W to meet the needs of the laser after amplification by the primary amplifying component 2.
[0054] In some embodiments of the present application, the eye-safe band fiber laser also includes a mode field adapter 31, which is connected between the second online isolator 24 and the secondary amplification component 3. The input end of the mode field adapter 31 is a 10 / 125 double-clad optical fiber, and the output end is a 20 / 125 double-clad optical fiber, which can withstand an average power greater than 3W.
[0055] Since the second in-line isolator 24 is a 10 / 125 double-clad fiber, and the second erbium-ytterbium co-doped double-clad fiber 32 is an erbium-ytterbium co-doped 20 / 125 double-clad fiber, a mode field adapter 31 is provided between the second in-line isolator 24 and the secondary amplifier assembly 3. The mode field adapter 31 is an optical device for connecting optical fibers of different core diameters, and can achieve a smooth transition between the second in-line isolator 24 and the second erbium-ytterbium co-doped double-clad fiber 32, ensuring stable transmission of optical signals. The mode field adapter 31 withstands an average power greater than 3W, which is consistent with the second in-line isolator 24.
[0056] In some embodiments of the present application, the eye-safe band fiber laser also includes an output isolator, the input end of the output isolator is connected to the signal end of the second combiner; the operating wavelength of the output isolator is 1550nm, the input optical fiber is a 20 / 125 double-clad optical fiber, it can withstand an average power greater than 10W, a peak power greater than 20kW, and an isolation greater than 25dB.
[0057] The output isolator 41 is located at the end of the amplification link, that is, the output end of the secondary amplification component 3. The signal end of the second combiner serves as the output end of the secondary amplification component. Therefore, the input end of the output isolator is connected to the signal end of the second combiner. The main function of the output isolator 41 is to prevent the laser from propagating in the reverse direction in the system. The working wavelength of the output isolator 41, 1550nm, is consistent with the output laser wavelength of the eye-safe band fiber laser. The input optical fiber is a 20 / 125 double-clad optical fiber that is consistent with the second erbium-ytterbium co-doped double-clad optical fiber 32, and can withstand an average power greater than 10W and a peak power greater than 20kW, meeting the laser requirements after secondary amplification. An isolation degree greater than 25dB can ensure that the reversely transmitted laser signal is greatly attenuated.
[0058] The following is an embodiment of the present invention.
[0059] like Figure 1As shown, the eye-safe band nanosecond pulse fiber laser of this example mainly includes three parts, namely a seed source component 1, which is composed of a tunable pulse fiber laser 11 and a first online isolator 12; a first-stage amplification component 2, which is composed of a first pump laser 21, a first combiner 22, a first erbium-ytterbium co-doped double-clad fiber 23, and a second online isolator 24; a second-stage amplification component 3, which is composed of a mode field adapter 31, a second erbium-ytterbium co-doped double-clad fiber 32, a second combiner 33, and a second pump laser 34. The structural relationship between the various components is: the output end of the tunable pulse fiber laser is connected to the input end of the first online isolator, the output end of the first online isolator is connected to the signal end of the first combiner, the output end of the first pump laser is connected to the pump end of the first combiner, the output end of the first combiner is connected to the first erbium ytterbium co-doped double-clad fiber, the other end of the first erbium ytterbium co-doped double-clad fiber is connected to the input end of the second online isolator, the output end of the second online isolator is connected to the input end of the mode field adapter, the output end of the mode field adapter is connected to the second erbium ytterbium co-doped double-clad fiber, the other end of the second erbium ytterbium co-doped double-clad fiber is connected to the output end of the second combiner, the pump end of the second combiner is connected to the second pump laser, and the signal end of the second combiner is connected to the input end of the output isolator 41.
[0060] Among them, the tunable pulse fiber laser 11, in this embodiment, is a tunable pulse fiber laser with a central wavelength of 1550nm, a line width less than 5nm, an output fiber 10 / 125 double-clad fiber, an output state of pulse, a peak power greater than 4W, a pulse width range of 10-1000ns, a total of 16 pulse widths to choose from, and a repetition frequency of 1-4000kHz.
[0061] In this example, both the first-stage amplification component 2 and the second-stage amplification component 3 use a cladding-pumped MOPA structure to amplify the signal light. In this example, each amplification module uses erbium-ytterbium co-doped double-cladding optical fiber, and the pump light source uses a 976nm multi-mode semiconductor laser. Using a two-stage amplification structure, the seed source power is amplified to 10W average power, greater than 20kW peak power, greater than 0.4mJ single pulse energy, pulse width range 10-1000ns, frequency range 1-4000kHz, to achieve high repetition rate, high power, high beam quality human eye-safe band nanosecond pulse laser output.
[0062] The optical path structure of this example is compact, simple, and has excellent output beam quality. It is the industry's first nanosecond pulse fiber laser with a maximum single pulse energy of 0.4mJ in the eye-safe band and an average power output of more than 10W. It is an ideal light source for polymer laser precision marking applications.
[0063] In summary, this embodiment is based on a tunable pulse fiber laser and uses a cladding pumped MOPA structure to amplify the signal light. In this example, each level of amplification module uses erbium-ytterbium co-doped double-cladding fiber, and the pump light source uses a 976nm multi-mode semiconductor laser. Using a two-stage amplification structure, the seed source power is amplified to 10W average power, greater than 20kW peak power, greater than 0.4mJ single pulse energy, pulse width range 10-1000ns, frequency range 1-4000kHz, achieving the first high repetition rate, high power, high beam quality human eye-safe band nanosecond pulse laser output in the field.
[0064] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. An eye-safe fiber laser, characterized in that: The eye-safe band fiber laser comprises: A laser seed source; the central wavelength of the laser seed source is 1550nm; At least one stage of amplification component; the amplification component includes a pump laser, an erbium-ytterbium co-doped double-clad optical fiber and a beam combiner, the laser seed source is connected to the erbium-ytterbium co-doped double-clad optical fiber, and the pump laser is connected to the erbium-ytterbium co-doped double-clad optical fiber through the beam combiner.
2. The eye-safe fiber laser according to claim 1, characterized in that: The laser seed source comprises a tunable pulse fiber laser, the line width of the tunable pulse fiber laser is less than 5nm, the output fiber is a 10 / 125 double-clad fiber, the output state is pulse, the peak power is greater than 4W, the pulse width range is 10-1000ns, and the repetition frequency is 1-4000kHz.
3. The eye-safe fiber laser according to claim 1, characterized in that: The eye-safe band fiber laser further comprises a first online isolator, which is connected between the laser seed source and the amplification component; The central wavelength of the first online isolator is 1550nm, the working bandwidth is 10nm, the input fiber is 10 / 125 double-clad fiber, the output fiber is 10 / 125 double-clad fiber, the average power it withstands is 300mW, the insertion loss is less than 1dB, and the isolation is greater than 25dB.
4. The eye-safe fiber laser according to claim 1, characterized in that: The amplification component comprises a first-stage amplification component, and the first-stage amplification component comprises a first pump laser, a first erbium-ytterbium co-doped double-clad optical fiber and a first beam combiner; The signal end of the first beam combiner is connected to the laser seed source, the pump end of the first beam combiner is connected to the first pump laser, and the output end of the first beam combiner is connected to the first erbium-ytterbium co-doped double-clad optical fiber, so that the first pump laser provides pump excitation to the first erbium-ytterbium co-doped double-clad optical fiber; The central wavelength of the first pump laser is 976±5nm, the output power is greater than 10W, the central wavelength is 976nm±5nm, and the output optical fiber is a 105 / 125 multimode optical fiber; the first erbium-ytterbium co-doped double-clad optical fiber is an erbium-ytterbium co-doped 10 / 125 double-clad optical fiber.
5. The eye-safe optical fiber laser according to claim 4, characterized in that: The optical fiber at the signal end of the first combiner is a 10 / 125 double-clad optical fiber, and the optical fiber at the pump end is a 105 / 125 multimode optical fiber. The pump light coupling efficiency is greater than 95%, the signal light withstand power is greater than 3W, and the pump light withstand power is greater than 10W.
6. The eye-safe optical fiber laser according to claim 4 or 5, characterized in that: The amplification component further includes a secondary amplification component, which includes a second pump laser, a second erbium-ytterbium co-doped double-clad optical fiber, and a second beam combiner; The second erbium-ytterbium co-doped double-clad optical fiber is connected to the first-stage amplification component, the pump end of the second beam combiner is connected to the second pump laser, and the output end of the second beam combiner is connected to the second erbium-ytterbium co-doped double-clad optical fiber, so that the second pump laser provides pump excitation to the second erbium-ytterbium co-doped double-clad optical fiber, and the signal end of the second beam combiner serves as the output end of the second-stage amplification component; The central wavelength of the second pump laser is 976±5nm, the output power is greater than 20W, the central wavelength is 976nm±5nm, and the output fiber is a 105 / 125 multimode fiber; the second erbium-ytterbium co-doped double-clad fiber is an erbium-ytterbium co-doped 20 / 125 double-clad fiber.
7. The eye-safe optical fiber laser according to claim 6, characterized in that: The optical fiber at the signal end of the second combiner is a 20 / 125 double-clad optical fiber, and the optical fiber at the pump end is a 105 / 125 multimode optical fiber. The pump light coupling efficiency of the second combiner is greater than 95%, the signal light withstand power is greater than 10W, and the pump light withstand power is greater than 20W.
8. The eye-safe fiber laser according to claim 6, characterized in that: The eye-safe band fiber laser also includes a second online isolator, which is connected between the first-stage amplification component and the second-stage amplification component. The second online isolator has a central wavelength of 1550nm, a working bandwidth of 10nm, an input fiber 10 / 125 double-clad fiber, an output fiber 10 / 125 double-clad fiber, an average power of 3W, an insertion loss of less than 1dB, and an isolation greater than 25dB.
9. The eye-safe band fiber laser according to claim 8, characterized in that: The eye-safe band fiber laser also includes a mode field adapter, which is connected between the second online isolator and the secondary amplification component. The input end of the mode field adapter is a 10 / 125 double-clad optical fiber, and the output end is a 20 / 125 double-clad optical fiber, and can withstand an average power greater than 3W.
10. The eye-safe band fiber laser according to claim 6, characterized in that: The eye-safe band fiber laser further comprises an output isolator, the input end of the output isolator being connected to the signal end of the second beam combiner; The output isolator has an operating wavelength of 1550nm, an input optical fiber of 20 / 125 double-clad optical fiber, an average power of more than 10W, a peak power of more than 20kW, and an isolation of more than 25dB.