Pulse fiber amplifier device integration device, system and method

Abstract

The present invention provides a pulse fiber amplifier device integrated device, system and method. The integrated device includes: a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module; the pump fiber is used to transmit the pump light output by the pump source to the first collimator; the first collimator is used to collimate the pump light output by the pump fiber and output it to the dichroic mirror; the dichroic mirror is used to reflect the pump light collimated by the first collimator; the end cap is used to transmit the pump light reflected by the dichroic mirror to the active fiber, and output the signal light amplified by the active fiber to the dichroic mirror; the dichroic mirror is also used to transmit the amplified signal light; the isolation module is used to transmit the amplified signal light transmitted by the dichroic mirror to the output module, and limit the reverse transmission of the amplified signal light; the output module is used to output the amplified signal light transmitted by the isolation module. The present invention realizes the integrated integration of pumping and high-peak high-quality pulse laser output.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber lasers, and in particular to a pulse optical fiber amplifier device integrated device, system and method thereof. Background Art

[0002] Fiber lasers can be divided into two working modes: continuous and pulsed according to their timing characteristics. For continuous fiber lasers, when the laser works for a long time, high-power pumping will cause a lot of heat to be generated in the cavity. At the same time, there are some other unfavorable factors that limit the further increase of laser output power. Pulse fiber amplifiers can release the energy stored in the cavity in a short time by controlling the pulse width of the laser. This can not only obtain high peak power output pulses, but also maintain good beam quality. Currently, nanosecond pulse fiber amplifiers have been widely used in material surface processing, thin metal cutting / welding and other application fields.

[0003] Conventional metal marking, welding and laser cleaning fields do not require high peak power for pulse fiber amplifiers, which are generally within 10kW. However, for some special applications, such as glass cutting and nonlinear frequency conversion, the peak power requirements for pulse fiber amplifiers are relatively high, generally in the tens of kW. High-peak power pulsed infrared fiber lasers have been applied to the field of glass cutting, gradually replacing traditional green light cutting; high-peak power pulsed infrared lasers can obtain high-peak power green light output through nonlinear frequency conversion. Due to their good beam quality, they are currently widely used in the field of solar cells such as PERC laser grooving and SE doping.

[0004] Looking at the development of nanosecond pulse fiber amplifiers over the past decade, it is known that to obtain pulsed laser output with high average power, high pulse energy and high peak power, it is usually necessary to use a master oscillator power amplifier structure (MOPA). The main factor limiting the further improvement of the peak power of current pulse fiber amplifiers is the nonlinear effects in the optical fiber, such as stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS). There are many factors that affect the nonlinear effects in MOPA pulse fiber amplifiers, such as the length of the optical fiber, the core diameter of the optical fiber, the pulse width and line width of the seed, the pumping method, etc. At present, in order to obtain high-peak power pulse fiber amplifiers, the mainstream is to use DFB-type semiconductor seed sources for amplification. At the same time, in order to suppress the nonlinear effects in MOPA pulse fiber amplifiers, the main solutions are as follows:

[0005] 1) The amplifier uses a reverse beam combiner for backward pumping, and a spatial fiber isolator is used for the output. Backward pumping can reduce the effective absorption length of the active fiber, which helps to suppress nonlinear effects. However, in the all-fiber pulse fiber amplifier, the passive fiber introduced is too long, which further increases the probability of nonlinear effects.

[0006] 2) The amplifier uses active optical fiber with a large mode field diameter, which reduces the power density in the fiber core to increase the threshold of the nonlinear effect. However, the large mode field diameter will excite more high-order modes in the fiber core, resulting in poor beam quality of the whole machine. It is generally used in non-precision processing fields such as laser cleaning.

[0007] 3) IPG uses GTWAVE fiber for power amplification. The advantage of GTWAVE fiber is that the pump combiner can be integrated on the active fiber, and the evanescent wave is used for reverse pumping excitation. The active fiber is directly output through the isolator / collimator, which reduces the length of the passive fiber and can effectively suppress the nonlinear effect in the fiber. However, GTWAVE fiber technology is currently blocked in China, and China has not made any substantial breakthroughs in this field.

[0008] 4) Patent CN115986534A proposes a new type of pulse amplifier output device, which recycles the forward residual pump light to a certain extent and reduces the use length of the active optical fiber to reduce the nonlinear effect. However, the forward pumping method itself is not friendly to the nonlinear effect due to the long effective length of the optical fiber, and the forward combiner has high stability requirements;

[0009] 5) Patent CN202110431771.6 provides an online integrated fiber optic device, a fiber laser amplification system and a fiber laser. The online integrated fiber optic device includes a pump source module, a coated lens group and a collimator. The collimator and the coated lens group are housed in the fiber optic device along the incident optical axis of the previous signal light. The pump source module emits pump light, and the pump light is reflected by the coated lens group and then coupled and output by the collimator to achieve power amplification of the previous signal light in the previous and / or next amplification system. The online fiber optic device described is essentially an optical path connector. In a complete fiber laser amplifier system, it is mainly used between the seed and the amplifier as a pre-amplification stage in the optical path, playing the role of transition and optical path monitoring. If used as a complete amplifier alone, it is difficult to achieve high-power, high-peak power laser output, because high power means high pump power injection, and the active fiber heat dissipation caused by the quantum loss brought by the high pump power is an important factor affecting the stability of the laser system. There is no effective and implementable means for the heat dissipation of active optical fibers, and it is difficult to implement it in specific engineering applications as a high-power amplifier. In addition, if used as an amplifier, a certain amount of passive optical fiber will inevitably be introduced at the output end. In addition, due to the inherent limitations of the forward pumping method, the nonlinear effects inside the system will be stronger, such as stimulated Raman scattering and stimulated Brillouin scattering, which will seriously restrict the increase in the peak power of the pulse amplifier. Summary of the invention

[0010] The present invention provides a pulse fiber amplifier device integration device, system and method thereof, which adopts a spatial optical path coupling method to realize the integrated integration of amplifier pumping and output, can shorten the use length of active optical fiber and energy transmission optical fiber, significantly improve the threshold of nonlinear effect inside the optical fiber, so as to realize high peak value pulse laser output, and at the same time have good beam quality of fiber laser.

[0011] In a first aspect, the present invention provides a pulse fiber amplifier device integrated device, characterized in that the integrated device comprises: a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module; wherein

[0012] The pump fiber is connected to a pump source and is used to output pump light to the first collimator;

[0013] The first collimator is used to collimate the pump light output by the pump fiber and output it to the dichroic mirror;

[0014] The dichroic mirror is used to reflect the pump light collimated and output by the first collimator;

[0015] The end cap is used to transmit the pump light reflected by the dichroic mirror to the active optical fiber, and output the signal light amplified by the active optical fiber to the dichroic mirror;

[0016] The dichroic mirror is also used to transmit the amplified signal light;

[0017] The isolation module is used to transmit the amplified signal light transmitted by the dichroic mirror to the output module, and to limit the reverse transmission of the amplified signal light;

[0018] The output module is used to output the amplified signal light transmitted by the isolation module.

[0019] In a second aspect, the present invention further provides a pulse fiber amplifier system, characterized in that the amplifier system comprises: a seed laser, a mode field adapter, an active fiber and at least one cascaded amplifier stage; wherein

[0020] The amplifier stage includes a pump source and a pulse fiber amplifier device integrated device, wherein the pump source is connected to a pump fiber of the integrated device for outputting pump light;

[0021] The seed laser is used to output seed signal light;

[0022] The input end of the mode field adapter is connected to the seed laser, the output end of the mode field adapter is connected to the active optical fiber, and the output end of the mode field adapter has a built-in cladding light filter for filtering the reverse pump light transmitted by the active optical fiber;

[0023] The other end of the active optical fiber is fused to the end cap of the integrated device.

[0024] In a third aspect, the present invention further provides a method for integrating a pulse fiber amplifier device, characterized in that the method comprises: packaging a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module into one to obtain an integrated device; wherein

[0025] The pump fiber transmits the pump light output by the pump source to the first collimator;

[0026] The first collimator collimates the pump light output by the pump fiber and outputs it to the dichroic mirror;

[0027] The dichroic mirror reflects the pump light collimated and output by the first collimator;

[0028] The end cap transmits the pump light reflected by the dichroic mirror to the active optical fiber, and outputs the signal light amplified by the active optical fiber to the dichroic mirror;

[0029] The dichroic mirror transmits the amplified signal light;

[0030] The isolation module transmits the amplified signal light transmitted by the dichroic mirror to the output module, and limits the reverse transmission of the amplified signal light;

[0031] The output module outputs the amplified signal light transmitted by the isolation module.

[0032] The pulse fiber amplifier device integration device, system and method provided by the present invention: first, realize the integrated integration of pulse fiber amplifier pump and output, improve the compactness of the amplifier and simplify the process flow; second, significantly improve the threshold of the fiber nonlinear effect, can effectively suppress SRS and SBS, and realize high peak power and high beam quality pulse laser output; third, can flexibly adjust the specifications of the output end cap to meet the use requirements of active optical fibers of different specifications, and can be used for one-stage or multi-stage optical path amplification systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 Schematic diagram of a pulse fiber amplifier device integration device provided by an embodiment of the present invention;

[0035] Figure 2 is a time curve diagram of output laser power provided by an embodiment of the present invention;

[0036] Figure 3 Schematic diagram of heat dissipation of a pulse fiber amplifier system provided by an embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of a pulse fiber amplifier system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. SUMMARY OF THE INVENTION

[0040] As mentioned above, the present invention provides a high average power, high peak power nanosecond and sub-nanosecond pulse fiber amplifier device integrated device, system and method, which utilizes reverse pumping to fully absorb the pump light; the active fiber heat dissipation is effectively solved; the nonlinear threshold is high, and the device is highly stable. In addition, the amplifier and the output end are integrated, which simplifies the laser structure and reduces the manufacturing cost; at the same time, it is highly flexible and can match fiber amplifiers with different core diameters.

[0041] Exemplary Devices

[0042] Figure 1 Schematic diagram of an integrated device of a pulse fiber amplifier device provided by an embodiment of the present invention, which can achieve nanosecond and sub-nanosecond pulse laser output with high peak power, such as Figure 2 As shown. Figure 1 As shown, the integrated device 100 provided in this embodiment includes: a pump fiber 101 (pump optical fiber), a first collimator 102 , a dichroic mirror 103 , an end cap 104 , an isolation module 105 and an output module 106 .

[0043] The pump fiber 101 is used to transmit the pump light output by the pump source to the first collimator 102 .

[0044] The pump source is usually a high-power laser diode or other type of laser, which is responsible for generating pump light. The pump light is a continuous light transmitted in the cladding of the optical fiber, and its wavelength is generally selected within the wavelength range that can be effectively absorbed by the rare earth doped ions (such as ytterbium or erbium ions) of the active optical fiber.

[0045] Preferably, the wavelength of the pump light output by the pump source is 976nm. The main reasons for selecting the pump light of this wavelength are: first, since the absorption cross section of ytterbium ions is the largest at 976nm, the pump light energy of this wavelength can be efficiently absorbed by the active optical fiber doped with ytterbium ions, thereby achieving high conversion efficiency; second, the pump light of this wavelength has a lower heat load characteristic, because at 976nm, the pump light is almost completely absorbed and converted into laser output, reducing the generation of waste heat, which helps to manage the heat of the entire system and improve the overall stability and life; third, the 976nm pump light can effectively suppress nonlinear effects in the optical fiber, such as stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS); fourth, the 976nm pump light is usually coupled with a single-mode optical fiber, which can produce a high-quality laser output beam, and the single-mode optical fiber helps to maintain good beam quality and efficient optical transmission.

[0046] The pump fiber 101 transmits the pump light emitted by the pump source into the integrated device 100 . Its core parameters include the core diameter, cladding diameter and numerical aperture (NA), which determine the transmission efficiency and mode characteristics of the pump light.

[0047] The core / cladding diameters of the pump fiber 101 include, but are not limited to, 105 / 125 μm, 110 / 125 μm, 135 / 155 μm, 200 / 220 μm and / or 220 / 242 μm. The specifications of the pump fiber 101 can be adjusted according to actual application requirements to accommodate different pump sources and laser designs.

[0048] The first collimator 102 is used to collimate the pump light output by the pump fiber 101 and output it to the dichroic mirror 103 .

[0049] The light beam in the pump fiber 101 is usually divergent. Direct use will cause the light beam to diffuse, making it difficult to couple efficiently to subsequent components.

[0050] The collimator is usually composed of a group of lenses, and its main function is to convert the divergent pump light beam into a parallel light beam to ensure that the pump light can be efficiently coupled into the subsequent optical components (such as the dichroic mirror 103), thereby reducing beam scattering and loss and achieving efficient light transmission and coupling.

[0051] The dichroic mirror 103 is used to reflect the pump light collimated and output by the first collimator 102 . The dichroic mirror 103 is also used to transmit the amplified signal light transmitted from the end cap 104 to the isolation module 105 .

[0052] The dichroic mirror 103 is an optical filter that has high reflectivity or high transmittance for light of a specific wavelength and is used to separate light of different wavelengths. The dichroic mirror 103 efficiently reflects light with a wavelength of 900 to 1000 nm and efficiently transmits light with a wavelength of 1000 to 1500 nm. For example, the dichroic mirror 103 efficiently reflects 915 nm / 976 nm pump light and simultaneously outputs a high transmittance of 1064 nm signal light.

[0053] In order to optimize the optical path of the pump light and the signal light to ensure efficient reflection and transmission, the dichroic mirror 103 is placed at 45° to the horizontal direction. The 45° placement of the dichroic mirror makes the optical path design more compact and efficient, reduces the loss and interference in the optical path, and the occupied space of the entire integrated device 100.

[0054] The present invention adopts reverse pumping technology to make the distribution of pump light in the active optical fiber more uniform, avoiding the phenomenon of gathering at the input end during forward pumping, thereby reducing the local high power density. Since the reverse pump light is gradually absorbed by the active optical fiber during transmission, the amount of residual pump light can be effectively reduced, making the pump light intensity in the active optical fiber more uniform, and reducing the threshold for inducing nonlinear effects.

[0055] The end cap 104 is used to transmit the pump light reflected by the dichroic mirror 103 to the active optical fiber, and output the signal light amplified by the active optical fiber to the dichroic mirror 103 .

[0056] Preferably, the end cap 104 is made of fused quartz, which has the advantages of high purity, high heat resistance and low thermal expansion coefficient, and is suitable for high-power optical applications to ensure optical performance and durability.

[0057] Specifically, the end cap 104 is fused with the active optical fiber to reduce the output power density of the end face of the active optical fiber; and receives the reverse pump light, converges the pump light to the end face of the active optical fiber, and completes the pump injection.

[0058] The end cap 104 is detachable for easy maintenance and replacement, and the specifications of the end cap 104 can be flexibly adjusted to meet the use requirements of active optical fibers of different specifications, and can be used in a single-stage or multi-stage amplification system.

[0059] It needs to be fused with the active optical fiber before being fixed in the integrated device 100, and then the fusion point of the two is placed on a heat dissipation device to prevent the active optical fiber from overheating and achieve high peak power and high beam quality pulse laser output. For example, the outer side of the input end of the end cap 104 is embedded in a water cooling plate to ensure that the active optical fiber can be fully cooled in the groove of the water cooling plate.

[0060] In order to improve the heat dissipation efficiency, the entire integrated device 100 and / or the active optical fiber 201 can also be placed on a heat dissipation device 202 (water cooling plate). Figure 3 shown.

[0061] In addition, the portion of the end cap 104 exposed outside the integrated device 100 also includes a protective structure 203, which is usually made of a high thermal conductivity material, such as a copper block, which not only provides mechanical protection, but also enhances the heat dissipation effect and can prevent dust from entering, thereby keeping the optical system clean and stable in performance. Figure 3 shown.

[0062] In short, effective heat dissipation can not only prevent the influence of thermal effects on fiber performance, but also suppress nonlinear effects, improve system efficiency and stability, and thus ensure the excellent performance of laser systems in various high-demand applications. In high-power fiber amplifier systems, the heat dissipation of active optical fibers 201 is particularly important:

[0063] First, when the high-power laser is in operation, the active optical fiber 201 absorbs the pump light and generates a large amount of heat. If the heat cannot be effectively dissipated, it will cause thermal effects on the optical fiber material, such as thermal lens effect, thermal distortion and thermal degradation. These thermal effects will affect the optical properties of the optical fiber, resulting in a decrease in beam quality, an increase in the inhomogeneity of the gain medium, and unstable laser output. In addition, overheating of the optical fiber will cause damage or melting of the optical fiber material, especially under high-power operating conditions. Effective heat dissipation can prevent permanent damage to the optical fiber at high temperatures, thereby ensuring the long-term reliable operation of the fiber laser.

[0064] Second, in high-power fiber amplifier systems, thermal effects will enhance nonlinear effects (such as SBS and SRS), thereby limiting the output power and quality of the laser. Through effective heat dissipation, the temperature of the active fiber 201 can be reduced, the probability of nonlinear effects can be reduced, and the output power and beam quality of the system can be improved.

[0065] Third, effective heat dissipation helps to keep the operating temperature of the active optical fiber 201 within a relatively stable range and improve the optical-optical conversion efficiency of the optical fiber. High-efficiency optical fiber amplifiers can not only output higher power, but also reduce energy loss and improve the energy utilization of the overall system. Stable operating temperature helps to maintain the stability of laser output and reduce power fluctuations and beam quality changes during the operation of the laser. For nanosecond and sub-nanosecond pulse fiber amplifier systems with high peak power, stability is particularly important.

[0066] Fourth, in applications that require long-term continuous operation, such as material processing, laser communications, and medical fields, high average power amplifier systems can improve work efficiency and processing speed. Effective heat dissipation management ensures that fiber lasers can operate stably for a long time at high power output without interruption due to overheating, and ensures that the fiber maintains structural and performance integrity during high peak pulse output.

[0067] The end cap 104 may further include a second collimator, which is used to collimate the amplified signal light output by the active optical fiber 201 and converge and couple the reverse pump light reflected by the dichroic mirror 103 to the input end face of the end cap 104 .

[0068] As a key component in the fiber amplifier, the end cap 104 ensures the high performance and reliability of the entire integrated device 100 by including a second collimator, using fused quartz material, and combining efficient heat dissipation design and protection structure. Its detachable design further improves the maintainability and flexibility of the integrated device 100, and facilitates the application of the fiber amplifier in high-power and high-precision laser output. Through efficient pump light transmission and signal light collimated output, the end cap 104 further optimizes the transmission performance of the fiber amplifier.

[0069] In addition, the second collimator can also be placed as a separate device between the end cap 104 and the dichroic mirror 103, such as Figure 1 As shown, the second collimator 107 is not included in the end cap 104. Compared with this solution, the aforementioned solution of embedding the second collimator in the end cap 104 can reduce the physical size of the system, making the entire integrated device 100 more compact; and reduce the number of independent components in the optical path, simplifying the installation and alignment process, and the optical components fixed in one component can be more easily kept in an aligned state, simplifying the optical path adjustment; in addition, the mechanical stability is improved.

[0070] The isolation module 105 is used to transmit the amplified signal light transmitted by the dichroic mirror 103 to the output module 106 and limit the reverse transmission of the amplified signal light to prevent the external signal light from returning to the amplifier system and causing device damage.

[0071] The isolation module 105 generally adopts optical isolator technology and uses non-reciprocal elements (such as Faraday rotators) to achieve unidirectional light transmission. The Faraday rotator rotates the polarization direction of light under the action of a magnetic field, thereby allowing light to pass in one direction and being blocked or deflected in the opposite direction.

[0072] The output module 106 is used to output the amplified signal light transmitted by the isolation module 105 .

[0073] The output module 106 includes a beam expansion module and / or a third collimator.

[0074] The beam expansion module is used to expand the output spot of the amplified signal light. More specifically, the beam expansion module is used to expand the output spot of the amplified signal light by multiples using a Kepler beam expansion system according to actual application requirements. The Kepler beam expansion system consists of two positive lenses. The front lens converges the light beam to a focus, and the rear lens collimates the converged light beam again for output. The combination of the two lenses is used to expand the spot diameter of the input light beam by a certain multiple. The expanded spot can reduce the divergence angle of the light beam, improve the beam quality, and at the same time reduce the peak power density in the optical fiber, further increasing the threshold of the nonlinear effect.

[0075] The third collimator is used to collimate and output the amplified signal light.

[0076] In summary, the integrated device 100 provided by the present invention adopts a spatial optical path coupling method to achieve integrated integration of laser pumping and output. By optimizing the optical path design, the use length of the active optical fiber 201 and the energy transmission optical fiber is reduced, thereby reducing the power density in the optical fiber. The lower power density reduces the optical power concentration in the optical fiber and reduces the possibility of nonlinear effects.

[0077] The integrated device 100 provided by the present invention has at least the following beneficial effects:

[0078] First, reverse pumping allows the pump light to be more fully absorbed in the active optical fiber 201, and the utilization efficiency of the pump light is higher, which helps to improve the overall power output. In addition, due to higher gain efficiency, more effective nonlinear effect suppression, more uniform pump distribution and optimized thermal management, the length of the active optical fiber 201 using reverse pumping will be shorter than that of forward pumping.

[0079] Second, the present invention designs an effective heat dissipation solution to ensure that the active optical fiber 201 can maintain a stable operating temperature under high power operation. Optimization of heat dissipation management helps to extend the life and stability of the integrated device 100, especially under high average power and high peak power operating conditions.

[0080] Third, through the application of reverse pumping technology, effective heat dissipation management, spatial optical path coupling, efficient reflection and transmission of the dichroic mirror 103, and the use of a beam expansion module, the present invention achieves a more uniform power distribution and a lower power density in the optical fiber. These designs and technologies work together to improve the nonlinear threshold of the integrated device 100, so that the present invention can maintain stability under high-power and high-peak operation conditions, suppress the generation of nonlinear effects, and thus achieve high-quality laser output.

[0081] Fourth, the amplifier and output are integrated into one, simplifying the overall structure. The number of optical components and connection components is reduced, thereby reducing complexity. The integrated design not only improves compactness, but also reduces optical losses in the optical path, improves light energy utilization, helps reduce manufacturing costs, reduces the number of required components and installation and debugging time, and simplifies the production process.

[0082] Fifth, by adjusting the specifications of the end cap 104, it is possible to match optical fiber amplifiers with different core diameters, so that the integrated device 100 can be widely used in various scenarios.

[0083] Sixth, the pump source is placed outside the integrated device 100, which is helpful for replacing and adjusting the pump source and also makes it easier to achieve heat dissipation of the pump source.

[0084] In summary, the present invention combines efficient reverse pumping technology with an effective heat dissipation solution to achieve nanosecond and sub-nanosecond pulse fiber laser amplification with high average power and high peak power. This design not only improves the utilization efficiency of pump light and the stability of the system, but also suppresses nonlinear effects and ensures high-quality laser output.

[0085] At the same time, by integrating the amplifier and the output end, the structure of the laser is simplified, the manufacturing cost is reduced, and high flexibility is provided for matching optical fiber amplifiers with different core diameters.

[0086] Exemplary Systems

[0087] Accordingly, an embodiment of the present invention further provides a pulse fiber amplifier system, such as Figure 4 As shown, the amplifier system 200 includes:

[0088] Seed laser 204, mode field adapter 205, active optical fiber 201 and at least one amplifier stage in cascade.

[0089] The amplifier stage includes a pump source 206 and an integrated device 100 . The pump source 206 is connected to a pump fiber 101 of the integrated device 100 to output pump light.

[0090] Each amplifier stage includes an independent pump source 206 and an integrated device 100, and the power of the signal light is further increased through cascade amplification. The cascade amplification design enables each stage to independently amplify the signal light, gradually increase the power output, and can adjust the number of amplification stages according to actual needs, providing a flexible power output range to meet the needs of different application scenarios.

[0091] Preferably, the wavelength of the pump light output by the pump source 206 is 976 nm.

[0092] The seed laser 204 is used to output seed signal light.

[0093] Preferably, the seed signal light has a pulse width of 3 ns, a Gaussian pulse waveform, a repetition frequency of 500 kHz, an output power of 600 mW, and an output optical fiber of the seed laser 204 is single-clad, with a core / cladding diameter of 10 / 125 μm.

[0094] The input end of the mode field adapter 205 is connected to the seed laser 204 , the output end of the mode field adapter 205 is connected to the active optical fiber 201 , and the output end of the mode field adapter 205 has a built-in cladding light filter for filtering the reverse pump light transmitted by the active optical fiber 201 .

[0095] Preferably, the optical fiber at the input end of the mode field adapter 205 is a single-clad passive optical fiber, and the diameter of the core / cladding thereof is 10 / 125 μm.

[0096] The output end optical fiber of the mode field adapter 205 is a double-clad passive optical fiber, the diameter of the core / cladding of which is 25 / 250 μm, and the NA is 0.065 / 0.22.

[0097] That is, the seed signal light enters the input end of the mode field adapter 205 and is transmitted through the single-clad passive optical fiber. The mode field adapter 205 converts the signal of the single-clad optical fiber and outputs it to the double-clad passive optical fiber to perform mode field adaptation and amplification of the signal light. The built-in cladding light filter filters out the reverse pump light transmitted back from the active optical fiber 201 to ensure the purity of the signal light. The signal light enters the active optical fiber 201 and is amplified by the interaction between the doping material (such as erbium or ytterbium) in the optical fiber and the pump light.

[0098] The other end of the active optical fiber 201 is fused to the end cap 104 of the integrated device 100 .

[0099] Preferably, the active optical fiber 201 is a double-clad polarization-maintaining optical fiber or a non-polarization-maintaining optical fiber, the diameter of the core / cladding of which is 25 / 250 μm, and the NA is 0.065 / 0.46.

[0100] It should be noted that although several devices, units, or modules of the pulse fiber amplifier device integrated system are mentioned in the above detailed description, this division is only exemplary and not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules described above can be embodied in one module. Conversely, the features and functions of one module described above can be further divided into multiple modules for embodiment.

[0101] Although the spirit and principle of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the disclosed specific embodiments, and the division of various aspects does not mean that the features in these aspects cannot be combined to benefit, and such division is only for the convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the attached claims.

[0102] The present invention provides:

[0103] 1. A pulse fiber amplifier device integrated device, characterized in that the integrated device comprises: a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module; wherein

[0104] The pump fiber is used to transmit the pump light output by the pump source to the first collimator;

[0105] The first collimator is used to collimate the pump light output by the pump fiber and output it to the dichroic mirror;

[0106] The dichroic mirror is used to reflect the pump light collimated and output by the first collimator;

[0107] The end cap is used to transmit the pump light reflected by the dichroic mirror to the active optical fiber, and output the signal light amplified by the active optical fiber to the dichroic mirror;

[0108] The dichroic mirror is also used to transmit the amplified signal light;

[0109] The isolation module is used to transmit the amplified signal light transmitted by the dichroic mirror to the output module, and to limit the reverse transmission of the amplified signal light;

[0110] The output module is used to output the amplified signal light transmitted by the isolation module.

[0111] 2. The integrated device according to item 1, characterized in that the end cap is fused with the active optical fiber;

[0112] The welding point of the two is placed on the heat sink.

[0113] 3. The integrated device according to item 2, characterized in that the end cap is detachable;

[0114] The portion of the end cap exposed from the integrated device includes a protective structure, which is used for dissipating heat and / or preventing dust from the exposed portion of the end cap.

[0115] 4. The integrated device according to item 3, characterized in that the end cap is made of fused quartz;

[0116] The protection structure is a copper pressing block.

[0117] 5. The integrated device according to any one of items 1 to 4 is characterized in that the end cap includes a second collimator, which is used to collimate the output of the amplified signal light output by the active optical fiber and converge the pump light reflected by the dichroic mirror to the end cap.

[0118] 6. The integrated device according to any one of items 1 to 4, characterized in that the integrated device and / or the active optical fiber are placed on a heat dissipation device.

[0119] 7. The integrated device according to any one of items 1 to 4, characterized in that the output module comprises a beam expansion module and / or a third collimator;

[0120] The beam expansion module is used to expand the output spot of the amplified signal light;

[0121] The third collimator is used to collimate and output the amplified signal light.

[0122] 8. The integrated device according to any one of items 1 to 4 is characterized in that the beam expansion module is used to multiply the output spot of the amplified signal light using a Kepler beam expansion system according to actual application requirements.

[0123] 9. The integrated device according to any one of items 1 to 4, characterized in that the dichroic mirror is placed at 45° to the horizontal direction;

[0124] The dichroic mirror efficiently reflects light with a wavelength of 900 to 1000 nm and efficiently transmits light with a wavelength of 1000 to 1500 nm.

[0125] 10. The integrated device according to any one of items 1 to 4 is characterized in that the core / cladding diameter of the pump fiber includes: 105 / 125 μm, 110 / 125 μm, 135 / 155 μm, 200 / 220 μm and / or 220 / 242 μm.

[0126] 11. A pulsed fiber amplifier system, characterized in that the amplifier system comprises: a seed laser, a mode field adapter, an active fiber and at least one cascaded amplifier stage; wherein

[0127] The amplifier stage comprises a pump source and an integrated device according to any one of items 1 to 10, wherein the pump source is connected to a pump fiber of the integrated device for outputting pump light;

[0128] The seed laser is used to output seed signal light;

[0129] The input end of the mode field adapter is connected to the seed laser, the output end of the mode field adapter is connected to the active optical fiber, and the output end of the mode field adapter has a built-in cladding light filter for filtering the reverse pump light transmitted by the active optical fiber;

[0130] The other end of the active optical fiber is fused to the end cap of the integrated device.

[0131] 12. The amplifier system according to item 11, characterized in that the input optical fiber of the mode field adapter is a single-clad passive optical fiber, and the diameter of its core / cladding is 10 / 125 μm;

[0132] The output end optical fiber of the mode field adapter is a double-clad passive optical fiber, the diameter of the core / cladding of which is 25 / 250 μm, and the NA is 0.065 / 0.22.

[0133] 13. The amplifier system according to item 11 or 12 is characterized in that the pulse width of the seed signal light is 3ns, with a Gaussian pulse waveform, a repetition frequency of 500kHz, an output power of 600mW, and the output optical fiber of the seed laser is single-clad, and its core / cladding diameter is 10 / 125μm.

[0134] 14. The amplifier system according to item 11 or 12 is characterized in that the active optical fiber is a double-clad polarization-maintaining or non-polarization-maintaining optical fiber, and its core / cladding diameter is 25 / 250 μm and NA is 0.065 / 0.46.

[0135] 15. The amplifier system according to item 11 or 12 is characterized in that the wavelength of the pump light output by the pump source is 976 nm.

[0136] 16. A method for integrating a pulse fiber amplifier device, characterized in that the method comprises: packaging a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module into one to obtain an integrated device; wherein

[0137] The pump fiber transmits the pump light output by the pump source to the first collimator;

[0138] The first collimator collimates the pump light output by the pump fiber and outputs it to the dichroic mirror;

[0139] The dichroic mirror reflects the pump light collimated and output by the first collimator;

[0140] The end cap transmits the pump light reflected by the dichroic mirror to the active optical fiber, and outputs the signal light amplified by the active optical fiber to the dichroic mirror;

[0141] The dichroic mirror transmits the amplified signal light;

[0142] The isolation module transmits the amplified signal light transmitted by the dichroic mirror to the output module, and limits the reverse transmission of the amplified signal light;

[0143] The output module outputs the amplified signal light transmitted by the isolation module.

[0144] 17. The integration method according to item 16, characterized in that the end cap is fused with the active optical fiber;

[0145] The method further comprises: placing the welding point of the two on a heat dissipation device.

[0146] 18. The integration method according to item 17, characterized in that the end cap is detachable;

[0147] The portion of the end cap exposed from the integrated device includes a protective structure, which is used for dissipating heat and / or preventing dust from the exposed portion of the end cap.

[0148] 19. The integration method according to item 18, characterized in that the end cap is made of fused quartz;

[0149] The protection structure is a copper pressing block.

[0150] 20. The integration method according to any one of items 16 to 19, characterized in that the end cap includes a second collimator;

[0151] The end cap transmits the pump light reflected by the dichroic mirror to the active optical fiber, and outputs the signal light amplified by the active optical fiber to the dichroic mirror, specifically including: the second collimator collimates and outputs the amplified signal light output by the active optical fiber, and converges the pump light reflected by the dichroic mirror to the end cap.

[0152] 21. The integration method according to any one of items 16 to 19, characterized in that the method further comprises: placing the integrated device and / or the active optical fiber on a heat dissipation device.

[0153] 22. The integration method according to any one of items 16 to 19, characterized in that the output module includes a beam expansion module and / or a third collimator;

[0154] The output module outputs the amplified signal light transmitted by the isolation module, specifically comprising:

[0155] The beam expansion module expands the output light spot of the amplified signal light;

[0156] The third collimator collimates the amplified signal light and outputs it.

[0157] 23. The integration method according to item 22 is characterized in that the beam expansion module expands the output spot of the amplified signal light by:

[0158] The beam expansion module uses a Kepler beam expansion system to multiple the output light spot of the amplified signal light according to actual application requirements.

[0159] 24. The integration method according to any one of items 16 to 19, characterized in that the dichroic mirror is placed at 45° to the horizontal direction;

[0160] The dichroic mirror efficiently reflects light with a wavelength of 900 to 1000 nm and efficiently transmits light with a wavelength of 1000 to 1500 nm.

[0161] 25. The integration method according to any one of items 16 to 19 is characterized in that the core / cladding diameter of the pump fiber includes: 105 / 125 μm, 110 / 125 μm, 135 / 155 μm, 200 / 220 μm and / or 220 / 242 μm.

Claims

1. A pulse fiber amplifier device integrated device, characterized in that: The integrated device comprises: a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module; wherein The pump fiber is used to transmit the pump light output by the pump source to the first collimator; The first collimator is used to collimate the pump light output by the pump fiber and output it to the dichroic mirror; The dichroic mirror is used to reflect the pump light collimated and output by the first collimator; The end cap is used to transmit the pump light reflected by the dichroic mirror to the active optical fiber, and output the signal light amplified by the active optical fiber to the dichroic mirror; The dichroic mirror is also used to transmit the amplified signal light; The isolation module is used to transmit the amplified signal light transmitted by the dichroic mirror to the output module, and to limit the reverse transmission of the amplified signal light; The output module is used to output the amplified signal light transmitted by the isolation module; The end cap is a detachable structure, and the portion exposed from the integrated device includes a protective structure, which is used to dissipate heat and / or prevent dust from the exposed portion of the end cap; The end cap is fused with the active optical fiber, and the fusion point of the two is exposed on the integrated device and placed on the heat dissipation device; The end cap has a built-in second collimator, which is used to collimate the amplified signal light output by the active optical fiber and converge the pump light reflected by the dichroic mirror to the fusion point of the end cap.

2. The integrated device according to claim 1, characterized in that: The end cap is made of fused quartz; The protection structure is a copper pressing block.

3. The integrated device according to claim 1 or 2, characterized in that: The integrated device and / or the active optical fiber are placed on a heat dissipation device.

4. The integrated device according to claim 1 or 2, characterized in that: The output module includes a beam expansion module and / or a third collimator; The beam expansion module is used to expand the output light spot of the amplified signal light; The third collimator is used to collimate and output the amplified signal light.

5. The integrated device according to claim 4, characterized in that: The beam expansion module is used to multiply the output spot of the amplified signal light by using a Kepler beam expansion system according to actual application requirements.

6. The integrated device according to claim 1 or 2, characterized in that: The dichroic mirror is placed at 45° to the horizontal direction; The dichroic mirror efficiently reflects light with a wavelength of 900 to 1000 nm and efficiently transmits light with a wavelength of 1000 to 1500 nm.

7. The integrated device according to claim 1 or 2, characterized in that: The core / cladding diameters of the pump fiber include: 105 / 125 μm, 110 / 125 μm, 135 / 155 μm, 200 / 220 μm and / or 220 / 242 μm.

8. A pulsed optical fiber amplifier system, characterized in that: The amplifier system comprises: a seed laser, a mode field adapter, an active optical fiber and at least one cascaded amplifier stage; wherein The amplifier stage comprises a pump source and an integrated device according to any one of claims 1 to 7, wherein the pump source is connected to a pump fiber of the integrated device for outputting pump light; The seed laser is used to output seed signal light; The input end of the mode field adapter is connected to the seed laser, the output end of the mode field adapter is connected to the active optical fiber, the output end of the mode field adapter has a built-in cladding light filter for filtering the reverse pump light transmitted by the active optical fiber, the input end optical fiber of the mode field adapter is a single-clad passive optical fiber, and the output end optical fiber of the mode field adapter is a double-clad passive optical fiber; The other end of the active optical fiber is fused to the end cap of the integrated device.

9. The amplifier system according to claim 8, characterized in that The core / cladding diameter of the optical fiber at the input end of the mode field adapter is 10 / 125 μm; The core / cladding diameters of the optical fiber at the output end of the mode field adapter are 25 / 250 μm, and the NA is 0.065 / 0.

22.

10. The amplifier system according to claim 8 or 9, characterized in that The seed signal light has a pulse width of 3 ns, a Gaussian pulse waveform, a repetition frequency of 500 kHz, and an output power of 600 mW. The output optical fiber of the seed laser is single-clad, and its core / cladding diameter is 10 / 125 μm.

11. The amplifier system according to claim 8 or 9, characterized in that The active optical fiber is a double-clad polarization-maintaining optical fiber or a non-polarization-maintaining optical fiber, the diameter of the core / cladding of which is 25 / 250 μm, and the NA is 0.065 / 0.

46.

12. The amplifier system according to claim 8 or 9, characterized in that The wavelength of the pump light output by the pump source is 976 nm.

13. A method for integrating a pulse fiber amplifier device, characterized in that: The method comprises: packaging a pump fiber, a first collimator, a dichroic mirror, an end cap, an isolation module and an output module into one body to obtain an integrated device; wherein The pump fiber transmits the pump light output by the pump source to the first collimator; The first collimator collimates the pump light output by the pump fiber and outputs it to the dichroic mirror; The dichroic mirror reflects the pump light collimated and output by the first collimator; The end cap transmits the pump light reflected by the dichroic mirror to the active optical fiber, and outputs the signal light amplified by the active optical fiber to the dichroic mirror; The dichroic mirror transmits the amplified signal light; The isolation module transmits the amplified signal light transmitted by the dichroic mirror to the output module, and limits the reverse transmission of the amplified signal light; The output module outputs the amplified signal light transmitted by the isolation module; The end cap is fused with the active optical fiber, and the fusion point of the two is placed on the heat dissipation device outside the integrated device; The end cap is detachable, and a protective structure is added to the portion of the end cap exposed from the integrated device to dissipate heat and / or prevent dust from the exposed portion of the end cap; The end cap has a built-in second collimator, which collimates and outputs the amplified signal light output by the active optical fiber, and converges the pump light reflected by the dichroic mirror to the end cap.

14. The integration method according to claim 13, characterized in that: The end cap is made of fused quartz; The protection structure is a copper pressing block.

15. The integration method according to claim 13 or 14, characterized in that: The method further comprises: placing the integrated device and / or the active optical fiber on a heat dissipation device.

16. The integration method according to claim 13 or 14, characterized in that: The output module includes a beam expansion module and / or a third collimator; The output module outputs the amplified signal light transmitted by the isolation module, specifically comprising: The beam expansion module expands the output light spot of the amplified signal light; The third collimator collimates the amplified signal light and outputs it.

17. The integration method according to claim 16, characterized in that: The beam expansion module expands the output spot of the amplified signal light by: The beam expansion module uses a Kepler beam expansion system to multiple the output spot of the amplified signal light according to actual application requirements.

18. The integration method according to claim 13 or 14, characterized in that: The dichroic mirror is placed at 45° to the horizontal direction; The dichroic mirror efficiently reflects light with a wavelength of 900 to 1000 nm and efficiently transmits light with a wavelength of 1000 to 1500 nm.

19. The integration method according to claim 13 or 14, characterized in that: The core / cladding diameters of the pump fiber include: 105 / 125 μm, 110 / 125 μm, 135 / 155 μm, 200 / 220 μm and / or 220 / 242 μm.

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