Switchable output wavelength laser, laser system, and wind-finding radar

Abstract

The application provides a switchable output wavelength laser, a laser system and a wind detection radar, and relates to the technical field of lasers.The laser comprises a pumping structure, a first optical fiber, a filtering structure and a wavelength switching structure, wherein the wavelength switching structure comprises a second optical fiber and an adjusting structure.The first optical fiber generates a second light beam based on a first light beam emitted by the pumping structure, the filtering structure filters the second light beam to obtain at least two target light beams, the second optical fiber obtains an output light beam based on the at least two target light beams, and the adjusting structure adjusts the bending degree of the second light beam.Different bending degrees of the second optical fiber correspond to different wavelengths of the output light beam.The laser can output laser beams of multiple wavelengths, and the wavelength of the output light beam can be selected by adjusting the bending degree of the second optical fiber.Meanwhile, the wavelength of the output light beam is selected by adjusting the bending degree of the second optical fiber, the flexible switching of output light beams of different wavelengths can be realized, and the switching is repeatable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lasers, in particular to a switchable output wavelength laser and a laser system. BACKGROUND

[0002] With the rapid development of the semiconductor industry, the application field of lasers is also more and more extensive, for example, material processing, optical fiber sensing, spectrum, laser radar system and the like.

[0003] However, with the wide application of lasers, the application scenarios of lasers are also more and more diverse. When the same laser is applied to different application scenarios, because the required laser wavelengths are different in different application scenarios, the laser needs to output laser beams of different wavelengths, and the wavelength of the output laser beam can be selected. SUMMARY

[0004] Therefore, the present application provides a switchable output wavelength laser, and the scheme is as follows:

[0005] A switchable output wavelength laser comprises a pumping structure, a first optical fiber, a filtering structure and a wavelength switching structure.

[0006] The pumping structure is used for generating a first light beam.

[0007] The first optical fiber receives the first light beam, generates a second light beam based on the first light beam, and transmits the second light beam to the filtering structure.

[0008] The filtering structure filters the second light beam to obtain at least two target light beams, the wavelengths of the at least two target light beams are different, and the wavelengths of the at least two target light beams are within the wavelength range of the second light beam.

[0009] The filtering structure transmits the at least two target light beams to the wavelength switching structure, the wavelength switching structure comprises a second optical fiber and an adjusting structure, the second optical fiber obtains an output light beam based on the at least two target light beams, the output light beam is one of the at least two target light beams; the adjusting structure is used for adjusting the bending degree of the second optical fiber, and different bending degrees of the second optical fiber correspond to different wavelengths of the output light beam.

[0010] Optionally, the wavelength switching structure further comprises a circulator, a first port of the circulator is in communication with the first optical fiber, a second port of the circulator is in communication with one end of the second optical fiber, a third port of the circulator is in communication with the other end of the second optical fiber, the at least two target light beams enter the second optical fiber in sequence through the first port and the second port of the circulator, and the output light beam is output in sequence through the third port and the first port of the circulator.

[0011] The second optical fiber comprises a first part and a second part in communication, and one end of the first part is in communication with the first port of the circulator, and one end of the second part is in communication with the third port of the circulator; the adjusting structure comprises a first displacement table and a second displacement table, the first displacement table is a movable displacement table, the first displacement table drives the first part to move, adjusts the bending degree of the first part, so that the first part obtains the output light beam based on the at least two target light beams; the second displacement table is a fixed displacement table, and the second displacement table is used for fixing the second part.

[0012] Optionally, further comprising: a fiber combiner;

[0013] The fiber combiner is located between the first optical fiber and the filtering structure, a first port of the fiber combiner is in communication with the pumping structure, a second port of the fiber combiner is in communication with the first optical fiber, and the first light beam enters the first optical fiber through the first port and the second port of the fiber combiner in sequence;

[0014] A third port of the fiber combiner is in communication with the filtering structure, the second light beam enters the filtering structure through the second port and the third port of the fiber combiner in sequence, the at least two target light beams enter the second optical fiber through the third port and the second port of the fiber combiner and the first optical fiber in sequence, and the output light beam is outputted through the first optical fiber, the second port and the third port of the fiber combiner and the filtering structure in sequence.

[0015] Optionally, the adjusting structure is located on a side of the circulator away from the first optical fiber, and the first displacement table and the second displacement table are arranged along a first direction, and the first direction is perpendicular to the arrangement direction of the adjusting structure and the circulator;

[0016] The first displacement table and the second displacement table have a preset distance, the first displacement table drives the first part to move along the first direction towards the second displacement table, adjusts the bending degree of the first part, so that the first part obtains the output light beam based on the at least two target light beams;

[0017] When the distance between the first displacement table and the second displacement table is the preset distance, the part of the first part between the first displacement table and the second displacement table is in a natural straight state.

[0018] Optionally, the at least two target light beams comprise a first target light beam and a second target light beam;

[0019] The filtering structure is an overlapping fiber Bragg grating.

[0020] Optionally, the pumping structure is a semiconductor laser, and the wavelength of the first light beam is 793 nm.

[0021] The first optical fiber is a thulium-doped optical fiber, and the wavelength of the second light beam ranges from 1900 nm to 2100 nm, inclusive.

[0022] The wavelength of the first target light beam is 2048.10 nm, and the wavelength of the second target light beam is 1940.64 nm.

[0023] Optionally, the preset distance between the first displacement table and the second displacement table is 10 cm.

[0024] The first displacement table drives the first part to move along the first direction towards the second displacement table, and the distance between the first displacement table and the second displacement table ranges from 10 cm to 6.6 cm, inclusive. The output light beam is the first target light beam.

[0025] The first displacement table drives the first part to move along the first direction towards the second displacement table, and the distance between the first displacement table and the second displacement table ranges from 6.5 cm to 5.5 cm, inclusive. The output light beam is the second target light beam.

[0026] Optionally, the temperature controller is further configured to control the temperature of the filtering structure to regulate the wavelengths of the at least two target light beams.

[0027] A laser system includes the laser with switchable output wavelengths according to any one of the above embodiments.

[0028] A wind measurement radar includes the laser with switchable output wavelengths according to any one of the above embodiments.

[0029] Compared with the related art, the technical solution of the present application has the following advantages:

[0030] The laser includes a pumping structure, a first optical fiber, a filtering structure, and a wavelength switching structure. The wavelength switching structure includes a second optical fiber and an adjusting structure. The first optical fiber generates a second light beam based on a first light beam emitted by the pumping structure. The filtering structure filters the second light beam to obtain at least two target light beams. The second optical fiber obtains an output light beam based on the at least two target light beams. The adjusting structure adjusts the bending degree of the second light beam. Different bending degrees of the second optical fiber correspond to different wavelengths of the output light beam. As can be seen, the laser can output laser beams of multiple wavelengths. The wavelength of the output light beam can be selected by the bending degree of the second optical fiber. The wavelength of the output light beam can be selected by the bending degree of the second optical fiber. The laser can also realize flexible switching of output light beams of different wavelengths, and has repeatability.

[0031] In addition, the laser can realize wavelength selection of the output beam by adjusting the bending degree of the second optical fiber, that is, by increasing the adjusting structure for adjusting the bending degree of the second optical fiber, which is simple in operation and low in cost compared with the related art. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by the drawings provided by the person skilled in the art without creative labor.

[0033] The structures, proportions, sizes, etc. shown in the drawings of the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by the person skilled in the art, and do not define the limiting conditions for the implementation of the present application, so they do not have technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, which does not affect the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0034] Figure 1 It is a structural schematic diagram of an existing laser;

[0035] Figure 2 It is a structural schematic diagram of another existing laser;

[0036] Figure 3 It is a structural schematic diagram of a switchable output wavelength laser provided by the present application;

[0037] Figure 4 It is a structural schematic diagram of another switchable output wavelength laser provided by the present application;

[0038] Figure 5 It is a structural schematic diagram of another switchable output wavelength laser provided by the present application;

[0039] Figure 6 It is a bending schematic diagram of the first part when the output beam is the first target beam;

[0040] Figure 7 It is a bending schematic diagram of the first part when the output beam is the second target beam;

[0041] Figure 8 It is a structural schematic diagram of another switchable output wavelength laser provided by the present application. DETAILED DESCRIPTION

[0042] With reference to the drawings and embodiments of the present application, the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0044] As described in the background section, the development trend of lasers today requires that the laser can output laser of multiple wavelengths, and the wavelength of the output laser can be selected.

[0045] For the above-mentioned problems, in the related art, as shown in Figure 1 Figure 1 is a structural schematic diagram of a laser in the related art, which is composed of a fiber ring resonator and an optical filter module. The fiber ring resonator includes a thulium-doped fiber amplifier (TDFA), a 90 / 10 coupler, a polarization controller, a circulator (CIR) and a collimator. When the thulium-doped fiber in the thulium-doped fiber amplifier is pumped by 793 nm laser, the thulium-doped fiber amplifier can generate amplified spontaneous emission (ASE) light in the range of 1910-2020 nm. After the ASE light passes through the coupler, 90% of the ASE light returns to the circulator and is further coupled to the optical filter module through the collimator.

[0046] ​The light filtering module comprises a diffraction grating (Grating), a collimating lens (Lens), a digital micromirror array (Digital Micromirror Device, DMD), wherein the collimating lens Lens is located between the diffraction grating Grating and the digital micromirror array DMD, and a controller (Remote control) is used to control the digital micromirror array DMD. The diffraction grating Grating and the digital micromirror array DMD are respectively placed on the front and rear focal planes of the collimating lens Lens. The collimator Collimator irradiates the ASE light onto the diffraction grating Grating to generate first-order dispersed light in the horizontal direction. Subsequently, the ASE light is collimated by the collimating lens Lens and projected onto different parts of the digital micromirror array DMD, thereby realizing longitudinal mode selection and wavelength tuning of the laser. Finally, the selected wavelength band that enters the ring cavity through the collimator is amplified by the thulium-doped fiber amplifier, and after several cycles, laser output is generated.

[0047] However, for the above-mentioned laser, the DMD chip has a high cost and requires high precision, thus resulting in high cost and complexity. In addition, as a MEMS device, the long-term stability and service life of the mechanical components of the DMD may not be as good as those of a pure optical or all-fiber structure. Moreover, the DMD chip contains movable micromirrors, which need to be regularly maintained and calibrated to ensure the accuracy of wavelength tuning and the stability of the laser. Based on the above, the laser inevitably faces problems such as high cost, short service life, and poor stability in real-world applications.

[0048] As shown in Figure 2 , Figure 2 is a structural schematic diagram of another laser in the related art, Figure 2 In the above-mentioned laser, LD is a pump source, FC (Fiber Combiner, FC) is a beam combiner, TDF (Thulium-Doped Fiber, TDF) is a thulium-doped fiber, CIR is a circulator, DI-PC is a polarization controller, SI-PM-FBG is an overlapping polarization-maintaining Bragg grating, and OC (Optical Coupler, OC) is an optical coupler. The laser uses a 793 nm laser diode with an output power of up to 12 w, a beam combiner FC, and a thulium-doped fiber TDF with a length of 5.9 m. 3+The double-clad fiber as an important part of the forward pumping structure provides sufficient gain for the laser operation in the ring cavity. The SI-PM-FBG (superimposed polarization maintaining Bragg grating) as a four-channel reflection filter cooperates with the circulator (CIR) to ensure the irreversible clockwise laser output, and the DI-PC has low loss at the 2050 nm band, so the DI-PC is selected to adjust the polarization state. The specific laser is injected from port 1 of the CIR and then reflected out through port 2, and the mode selection mechanism is realized by a composite double-ring cavity composed of three optical couplers OC.

[0049] Based on the above, Figure 2 The laser passes through the SI-PM-FBG for filtering, the composite ring cavity composed of OC1, OC2 and OC3 for mode selection, the excess longitudinal modes are filtered out, and the wavelength selection and wavelength tuning are performed by adjusting the DI-PC. The specific DI-PC is used to adjust the polarization state, the wavelength selection and switching are realized by introducing polarization-dependent loss and gain competition, and by changing the setting of the DI-PC, switching between four wavelengths can be realized, realizing single-wavelength, dual-wavelength, triple-wavelength and quadruple-wavelength output. However, the above ring cavity laser including multiple optical couplers OC has a complicated structure and a long cavity length, which is not easy to integrate and miniaturize in industrial design, and is not conducive to mass production. In addition, it is necessary to strictly control the length of the composite ring cavity composed of OC, so the fault tolerance is low in the industrial production process, and the manufacturing difficulty is great.

[0050] Based on the above, the application provides a switchable output wavelength laser, which comprises: Figure 3 As shown, Figure 3 A structure diagram of a switchable output wavelength laser provided by the application is shown, which comprises a pumping structure 100, a first optical fiber 200, a filtering structure 300 and a wavelength switching structure 400.

[0051] The pumping structure 100 is used to generate a first light beam, which can be referred to as pump light.

[0052] The first optical fiber 200 is in communication with the pumping structure 100, the first optical fiber 200 receives the first light beam, generates a second light beam based on the first light beam, and transmits the second light beam to the filtering structure 300, that is, the first optical fiber 200 can generate the second light beam based on the first light beam, and also can make the second light beam enter the filtering structure 300.

[0053] The filtering structure 300 is configured to filter the second light beam to obtain at least two target light beams, the at least two target light beams have different wavelengths, and the wavelengths of the at least two target light beams are within the wavelength range of the first light beam. That is, the filtering structure 300 can filter the second light beam to filter at least two lasers with different wavelengths from the second light beam. It should be noted that the at least two target light beams are output light beams that can be output by the laser, that is, the laser can output at least two laser beams with different wavelengths, that is, the laser can output laser beams with multiple wavelengths.

[0054] The filtering structure 300 further transmits the at least two target light beams to the wavelength switching structure 400, and the wavelength switching structure 400 includes a second optical fiber 410 and an adjusting structure 420. The second optical fiber 410 receives the at least two target light beams, and the second optical fiber 410 is configured to obtain an output light beam from the at least two target light beams. The output light beam is one of the at least two target light beams. The adjusting structure 420 is configured to adjust the bending degree of the second optical fiber 410. Different bending degrees of the second optical fiber 410 correspond to different wavelengths of the output light beam. That is, the bending degree of the second optical fiber 410 is different, and the wavelength of the output light beam obtained by the second optical fiber 410 based on the at least two target light beams is different. Then, the bending degree of the second optical fiber 410 can be changed by the adjusting structure 420 to obtain different output light beams. It should be noted that because the light loss of the laser beams with different wavelengths transmitted in the second optical fiber 410 is different due to the different bending degrees of the second optical fiber 410, the light loss of the at least two target light beams in the second optical fiber 410 can be controlled by adjusting the bending degree of the second optical fiber 410, that is, the light loss of the at least two target light beams in the second optical fiber 410 is different, so as to realize the selection of the output light beam. The output light beam is the light beam corresponding to the bending degree of the second optical fiber 410 with smaller light loss among the at least two target light beams.

[0055] As can be seen from the above, the laser can output laser beams with multiple wavelengths, and the wavelength selection of the output light beam can be realized by the bending degree of the second optical fiber 410, which can meet the development trend of the requirement of the laser for multiple wavelength output and the wavelength selection of the output light beam. At the same time, the wavelength selection of the output light beam can be realized by the bending degree of the second optical fiber 410, which can realize the flexible switching of the output light beams with different wavelengths and has repeatability.

[0056] In addition, the wavelength selection of the output light beam can be realized by adjusting the bending degree of the second optical fiber 410, that is, the adjusting structure for adjusting the bending degree of the second optical fiber 410 can be added, which is simple to operate and low in cost compared with the related art. For example, a DMD chip with high precision requirement and high price is not needed, and multiple optical couplers OC are not needed.

[0057] In addition, compared to lasers that include DMD chips, this laser does not have movable microlenses or other components that require regular maintenance and calibration, resulting in better stability and a longer lifespan, which is not affected by the lifespan of the DMD chip.

[0058] Compared to lasers with multiple optical couplers (OCs), which rely on multiple OCs to select the wavelength of the output beam, resulting in a complex structure and long cavity length, this laser achieves output wavelength selection solely through the bending of the second fiber 410. This avoids structural complexity and cavity length, thus preserving the laser's integration and miniaturization capabilities. In fact, it facilitates integration and miniaturization, while its simple structure allows for integration into more complex systems. Furthermore, lasers with multiple OCs require strict control over the length of the composite ring cavity formed by the OCs, making manufacturing difficult. This laser, however, only requires an adjustment structure to regulate the bending degree of the second fiber 410, resulting in lower cost and easier manufacturing.

[0059] In summary, the switchable output wavelength laser provided in this application can output laser beams of multiple wavelengths, and the output wavelength can be flexibly switched. Furthermore, compared with related technologies, this laser also has advantages such as simple operation, low cost, long lifespan, high stability, low manufacturing difficulty, miniaturization, and ease of integration, and has broad application prospects.

[0060] In one embodiment of this application, such as Figure 4 As shown, Figure 4 This application provides a schematic diagram of a switchable output wavelength laser. For the wavelength switching structure 400, the wavelength switching structure 400 further includes a circulator 430. The first port 431 of the circulator 430 is connected to the first optical fiber 200, meaning that the other end of the first optical fiber 200, except for its connection to the pump structure 100, is connected to the first port 441 of the circulator 430. The second port 432 of the circulator 430 is connected to one end of the second optical fiber 410, allowing the second optical fiber 410 and the first optical fiber 200 to be interconnected through the first port 431 and the second port 432 of the circulator 430. Therefore, at least two target beams, after passing through the first optical fiber 200, can sequentially enter the second optical fiber 410 through the first port 441 and the second port 442 of the circulator 430.

[0061] The third port 433 of the circulator 430 is in communication with the other end of the second optical fiber 410, so that the output light beam can be output through the third port 433 and the first port 431 of the circulator 430. It should be noted that the first to third ports of the circulator 430 are arranged in a clockwise direction, and the light beam entering the circulator 430 can only be transmitted in a specified direction, for example, the light beam entering the circulator 430 through the first port 431 can only be transmitted to the second port 432 through the single-mode optical fiber between the first port 431 and the second port 432, and then output from the second port 432; the light beam entering the circulator 430 through the second port 432 can only be transmitted to the third port 433 through the single-mode optical fiber between the second port 432 and the third port 433, and then output from the third port 433; the light beam entering the circulator 430 through the third port 433 can only be transmitted to the first port 431 through the single-mode optical fiber between the third port 433 and the first port 431, and then output from the first port 431, so as to realize the directional transmission of the light beam entering the circulator 430.

[0062] Based on the above, the second optical fiber 410 can include the first portion 411 and the second portion 412 in communication in sequence, that is, the second optical fiber 410 can include the first portion 411 and the second portion 412 in communication in sequence and end to end. Wherein one end of the first portion 411 is in communication with the first port 431 of the circulator 430, and one end of the second portion 412 is in communication with the third port 433 of the circulator 430.

[0063] The adjustment structure 420 includes a first displacement table 421 and a second displacement table 422. The first displacement table 421 is a movable displacement table, and the first displacement table 421 drives the first portion 411 to move to adjust the bending degree of the first portion 411, so that the first portion 411 can obtain the output light beam based on at least two target light beams. The second displacement table 422 is a fixed displacement table, and the second displacement table 422 is used to fix the second portion 412 to avoid the second portion 412 of the second optical fiber 410 from deforming due to the movement of the first portion 411 driven by the first displacement table 421, so as to reduce the light loss of the output light beam, ensure the efficient output of the output light beam, and further ensure the light efficiency of the laser.

[0064] In an embodiment of the present application, as Figure 5As shown, the laser further comprises a fiber combiner 500 located between the first optical fiber 200 and the filter structure 300, specifically, a first port 501 of the fiber combiner 500 is in communication with the pump structure 300, and a second port 502 of the fiber combiner 500 is in communication with the first optical fiber 200, and the first light beam enters the first optical fiber 200 in sequence through the first port 501 and the second port 502 of the fiber combiner 500, that is, the first light beam generated by the pump structure 300 can enter the fiber combiner 500 through the first port 501 of the fiber combiner 500, and then enter the first optical fiber 200 through the second port 502 of the fiber combiner 500. Optionally, the fiber combiner 500 can be a (2+1) x 1 multimode fiber combiner, and the core diameter can be 105 μm.

[0065] The third port 503 of the fiber combiner 500 is in communication with the filter structure 300. Based on this, the second light beam enters the filter structure 300 in sequence through the second port 502 and the third port 503 of the fiber combiner 500, specifically, after the first optical fiber 200 generates the second light beam based on the first light beam, the second light beam can enter the fiber combiner 500 through the second port 502 of the fiber combiner 500, and then enter the filter structure 300 through the third port 503 of the fiber combiner 500.

[0066] The at least two target light beams enter the second optical fiber 410 in sequence through the third port 503 and the second port 502 of the fiber combiner 500 and the first optical fiber 200, specifically, the filter structure 300 obtains the at least two target light beams based on the second light beam, and reflects the at least two target light beams, so that the at least two target light beams can enter the fiber combiner 500 through the third port 503 of the fiber combiner 500, and then enter the first optical fiber 200 through the second port 502 of the fiber combiner 500, and enter the second optical fiber 410 through the first optical fiber 200.

[0067] The output light beam is output in sequence through the first optical fiber 200, the second port 502 and the third port 503 of the fiber combiner 500, and the filter structure 300, specifically, after the output light beam is output through the first port 401 of the circulator 430, it enters the first optical fiber 200, and then enters the fiber combiner 500 through the second port 502 of the fiber combiner 500, and then enters the filter structure 300 through the third port 503 of the fiber combiner 500, and finally is output through the output port Laser output in communication with the filter structure 300.

[0068] Based on the above, the laser comprises the fiber combiner 500, which can efficiently transmit the laser beam to the next stage structure, which helps to reduce the optical loss of the laser and improve the optical efficiency of the laser.

[0069] In an embodiment of the present application, as Figure 5As shown, the adjusting structure 420 is located on the side of the circulator 430 away from the first optical fiber 200, and the first displacement table 421 and the second displacement table 422 are arranged along a first direction, which is perpendicular to the arrangement direction of the adjusting structure 420 and the circulator 430.

[0070] The first displacement table 421 and the second displacement table 422 have a preset distance therebetween, and the first displacement table 421 can drive the first part 411 to move along the first direction towards the second displacement table 422, so as to adjust the bending degree of the first part 411, so as to bend the second optical fiber 410 to a preset bending degree, and thus the first part 411 of the second optical fiber 410 can obtain an output light beam based on at least two target light beams.

[0071] The first part 411 located between the first displacement table 421 and the second displacement table 422 is in a natural straight state when the distance between the first displacement table 421 and the second displacement table 422 is the preset distance, so that the first displacement table 421 drives the first part 411 to move along the first direction towards the second displacement table 422, so as to adjust the bending degree of the first part 411, and thus the second optical fiber 410 can be bent to a preset bending degree.

[0072] As can be seen from the above, the laser device controls the bending degree of the first part 411 of the second optical fiber 410 through the first displacement table. Since the displacement table can accurately control the movement precision, the bending degree of the first part 411 can be accurately controlled, and thus the output wavelength selection and tuning can be accurately realized. The laser device can also flexibly switch between output light beams of different wavelengths, which is very important for application scenarios that require precise control of output wavelengths.

[0073] Based on the above, in one specific embodiment of the present application, as shown in Figure 5 The second optical fiber 410 has a rectangular shape, and the adjusting structure 420 and the circulator 430 can be located on the opposite two sides of the rectangle formed by the second optical fiber 410, respectively. The region where the first part 411 and the second part 412 of the second optical fiber 410 are connected is fixed to the second displacement table 422, so that the first displacement table 421 drives the first part 411 to move along the first direction towards the second displacement table 422, and the second part 412 does not change its form, thereby ensuring the light efficiency of the laser device.

[0074] In one embodiment of the present application, the at least two target light beams include a first target light beam and a second target light beam, i.e., the laser device provided by the present application can output two wavelengths of laser beams, but the present application does not limit this. The at least two target light beams can also include at least three wavelengths of laser beams, depending on the specific situation.

[0075] When the at least two target beams include two wavelengths of laser beams of the first target beam and the second target beam, correspondingly, the filtering structure 300 is an overlapping fiber Bragg grating. The first filter wavelength of the overlapping fiber Bragg grating is equal to the wavelength of the first target beam, and the second filter wavelength is equal to the wavelength of the second target beam. The first target beam and the second target beam can be filtered out from the second beam, and then the first target beam and the second target beam are obtained, that is, the above-mentioned at least two target beams are obtained.

[0076] Thulium-doped fiber lasers with a wavelength range of 1900nm-2100nm can be widely used in material processing, fiber sensing, spectroscopy, laser radar systems, Ho:YAG laser pumping and other fields, and therefore are increasingly attracting people's attention. For the above-mentioned thulium-doped fiber laser, the laser with a wavelength of 2.05μm has an atmospheric transmittance as high as 70%, which is particularly suitable for free-space applications, such as free-space optical communication. In addition, TDFL operating at a laser wavelength of 1.94μm seems to be more effective than Ho:YAG laser in invasive surgery (such as lithotripsy). Based on the above, a laser that takes into account the output wavelength of 2.05μm and 1.94μm and has switchable output wavelength becomes particularly important. Therefore, in an embodiment of the present application, the pump structure 100 can be a semiconductor laser (Laser Diode, abbreviated as LD), and the output wavelength of the pump structure 100, i.e., the wavelength of the first beam, can be 793nm. The first fiber 200 can be a thulium-doped fiber, and the wavelength of the second beam can be in the range of 1900nm-2100nm, including the end point value. Based on the above, the first filter wavelength of the filtering structure 300 can be 2048.10nm, and the second filter wavelength can be 1940.64nm, and then the wavelength of the first target beam can be 2048.10nm, and the wavelength of the second target beam can be 1940.64nm.

[0077] It should be noted that when the wavelength of the first beam generated by the pump structure 100 is 793nm and the first fiber 200 is a thulium-doped fiber, the process of generating the second beam by the first fiber 200 based on the first beam can be: after the first beam enters the first fiber 200, the Tm 3+ ions in the first fiber 200 absorb the first beam and transition to the upper energy level. As the number of upper energy level particles increases, population inversion occurs, causing the Tm 3+ ions in the excited state to transition to the ground state energy level, generating radiation photons, and the radiation photons are amplified to generate the second beam.

[0078] It should be further noted that although the wavelength of the first target light beam is 2048.10 nm and the wavelength of the second target light beam is 1940.64 nm in the above embodiment, the present application is not limited thereto, and the specific wavelength can be determined as appropriate.

[0079] In an embodiment of the present application, the pump structure 100 can be a commercial pump source of CS Rayzer Optical technology company, and the maximum output power thereof is 12 W. The first optical fiber 200 can be a thulium-doped optical fiber with a cladding absorption peak of 4.5 dB / m at 793 nm, and the core / cladding numerical apertures thereof are 0.15 / 0.46, and the core and cladding diameters thereof are 10 μm and 130 μm, respectively.

[0080] In an embodiment of the present application, the preset distance between the first displacement table 421 and the second displacement table 422 can be 10 cm. However, the present application is not limited thereto, and the specific distance can be determined as appropriate.

[0081] Based on the above, when the preset distance between the first displacement table 421 and the second displacement table 422 is 10 cm, as shown in FIG. 4B, the first displacement table 421 drives the first part 411 of the second optical fiber 410 to move in the first direction toward the second displacement table 422, and the distance between the first displacement table 421 and the second displacement table 422 is 10 cm~6.6 cm, including the end point value, and the output light beam is the first target light beam. Figure 6 As shown in FIG. 4C, the first displacement table 421 drives the first part 411 of the second optical fiber 410 to move in the first direction toward the second displacement table 422, and the distance between the first displacement table 421 and the second displacement table 422 is 6.5~5.5 cm, including the end point value, and the output light beam is the second target light beam.

[0082] Figure 7 As shown in FIG. 4C, the first displacement table 421 drives the first part 411 of the second optical fiber 410 to move in the first direction toward the second displacement table 422, and the distance between the first displacement table 421 and the second displacement table 422 is 6.5~5.5 cm, including the end point value, and the output light beam is the second target light beam.

[0083] ​Based on the above, when the distance between the first displacement stage 421 and the second displacement stage 422 is 10cm to 6.6cm, the output beam is the first target beam; when the distance is 6.5cm to 5.5cm, the output beam is the second target beam. That is, as the curvature of the first portion 411 of the second optical fiber 410 increases, the output beam changes from the first target beam to the second target beam. It should be noted that when the distance between the first displacement stage 421 and the second displacement stage 422 is 10cm, the output beam is the first target beam; that is, when the first portion 411 of the second optical fiber 410 is not bent, the output beam is the first target beam. It should also be noted that when the distance between the first displacement stage 421 and the second displacement stage 422 is less than 5.5cm, the curvature of the first portion 411 of the second optical fiber 410 is too large, resulting in excessive optical loss in both the first and second target beams, and no laser beam output.

[0084] In one embodiment of this application, the laser further includes a temperature controller 600 disposed on the filter structure 300 for controlling the temperature of the filter structure 300 to adjust the wavelengths of at least two target beams and to fine-tune the wavelengths of the at least two target beams. For example, by using the temperature controller 600 to raise the temperature of the filter structure 300 from 50°C to 300°C, the wavelength range of the first target beam can be 2048.44nm~2052.00nm, and the wavelength range of the second target beam can be 1940.98nm~1944.30nm.

[0085] It should be noted that the resonator of the laser described in any of the above embodiments can be a linear cavity structure.

[0086] like Figure 8 As shown, Figure 8 This application provides a structural diagram of a switchable output wavelength laser. Figure 8 In this design, the semiconductor laser LD is the pump structure 100, the thulium-doped fiber TDF is the first fiber 200, the overlapping fiber Bragg grating SI-FBG is the filter structure 300, the circulator CIR is the circulator 430, and the fiber combiner FC is the fiber combiner 500. Based on these specifications, components such as the pump structure 100, circulator 430, and fiber combiner 500 in this laser can all be commercially available products, contributing to the laser's reliability and replicability. They also facilitate laser maintenance and component replacement, making it highly practical.

[0087] This application also provides a laser system comprising the switchable output wavelength laser described in any of the above embodiments.

[0088] The application also provides a wind measurement radar, comprising the switchable output wavelength laser described in any of the above embodiments.

[0089] The various embodiments in the specification are described in a progressive or parallel or combination of progressive and parallel manner, and each embodiment focuses on the difference from other embodiments. The same or similar regions between various embodiments can be referred to each other. For the device disclosed by the embodiments, since it corresponds to the method disclosed by the embodiments, the description is relatively simple, and the related parts can be referred to the method area description.

[0090] It should be noted that in the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional 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 particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there can be a component disposed therebetween.

[0091] It should also be noted that in this document, relational terms such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, an element defined by the phrase "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or apparatus that includes the above-mentioned element.

[0092] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A switchable output wavelength laser, characterized by, The application relates to a wavelength switching structure. The wavelength switching structure comprises a pump structure, a first optical fiber, a filter structure and the wavelength switching structure. The pump structure is used for generating a first light beam. The first optical fiber receives the first light beam, generates a second light beam based on the first light beam and transmits the second light beam to the filter structure. The filter structure filters the second light beam to obtain at least two target light beams, the wavelengths of the at least two target light beams are different from each other, and the wavelengths of the at least two target light beams are within the wavelength range of the second light beam. The filter structure transmits the at least two target light beams to the wavelength switching structure, the wavelength switching structure comprises a second optical fiber and an adjusting structure, the second optical fiber obtains an output light beam based on the at least two target light beams, the output light beam is one of the at least two target light beams, and the adjusting structure is used for adjusting the bending degree of the second optical fiber, different bending degrees of the second optical fiber correspond to different wavelengths of the output light beam.

2. The switchable output wavelength laser of claim 1, wherein, The wavelength switching structure further comprises a circulator, a first port of the circulator is in communication with the first optical fiber, a second port of the circulator is in communication with one end of the second optical fiber, a third port of the circulator is in communication with the other end of the second optical fiber, the at least two target light beams enter the second optical fiber through the first port and the second port of the circulator in sequence, and the output light beam is output through the third port and the first port of the circulator in sequence. The second optical fiber comprises a first part and a second part in communication, one end of the first part is in communication with the first port of the circulator, and one end of the second part is in communication with the third port of the circulator; the adjusting structure comprises a first displacement table and a second displacement table, the first displacement table is a movable displacement table, the first displacement table drives the first part to move, adjusts the bending degree of the first part, so that the first part obtains the output light beam based on the at least two target light beams; and the second displacement table is a fixed displacement table, and the second displacement table is used for fixing the second part.

3. The switchable output wavelength laser of claim 2, wherein, The application further relates to a fiber combiner. The fiber combiner is located between the first optical fiber and the filter structure, a first port of the fiber combiner is in communication with the pump structure, a second port of the fiber combiner is in communication with the first optical fiber, and the first light beam enters the first optical fiber through the first port and the second port of the fiber combiner in sequence. A third port of the fiber combiner is in communication with the filter structure, the second light beam enters the filter structure through the second port and the third port of the fiber combiner in sequence, the at least two target light beams enter the second optical fiber through the third port and the second port of the fiber combiner and the first optical fiber in sequence, and the output light beam is output through the first optical fiber, the second port and the third port of the fiber combiner and the filter structure in sequence. The adjusting structure is located on the side, away from the first optical fiber, of the circulator, and the first displacement table and the second displacement table are arranged along a first direction, and the first direction is perpendicular to the arrangement direction of the adjusting structure and the circulator.

4. The switchable output wavelength laser of claim 3, wherein, ​ The first displacement table and the second displacement table have a preset distance, the first displacement table drives the first part to move along the first direction towards the second displacement table, and the bending degree of the first part is adjusted to make the first part obtain the output light beam based on the at least two target light beams; When the distance between the first displacement table and the second displacement table is the preset distance, the part of the first part between the first displacement table and the second displacement table is in a natural straight state.

5. The switchable output wavelength laser of claim 4, wherein, The at least two target light beams include a first target light beam and a second target light beam; The filter structure is an overlapping fiber Bragg grating.

6. The switchable output wavelength laser of claim 5, wherein, The pump structure is a semiconductor laser, and the wavelength of the first light beam is 793 nm; The first optical fiber is a thulium-doped optical fiber, and the wavelength of the second light beam ranges from 1900 nm to 2100 nm, inclusive. The wavelength of the first target light beam is 2048.10 nm, and the wavelength of the second target light beam is 1940.64 nm.

7. The switchable output wavelength laser of claim 5, wherein, The preset distance between the first displacement table and the second displacement table is 10 cm; The first displacement table drives the first part to move along the first direction towards the second displacement table, the distance between the first displacement table and the second displacement table is 10 cm to 6.6 cm, inclusive, and the output light beam is the first target light beam; The first displacement table drives the first part to move along the first direction towards the second displacement table, the distance between the first displacement table and the second displacement table is 6.5 cm to 5.5 cm, inclusive, and the output light beam is the second target light beam.

8. The switchable output wavelength laser of claim 1, wherein, Further comprising: A temperature controller for controlling the temperature of the filter structure to regulate the wavelengths of the at least two target light beams.

9. A laser system, characterized by, The laser with switchable output wavelength includes any one of claims 1-8.

10. A wind finding radar, characterized by The laser with switchable output wavelength includes any one of claims 1-8.

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