CN119651323A - Multi-wavelength laser - Google Patents

Abstract

The invention discloses a multi-wavelength laser, which relates to the technical field of lasers, and comprises a first output device, a cladding light filter, a first light source component, a composite resonant cavity, a second light source component and a second output device which are sequentially connected through a central fiber, wherein the composite resonant cavity is internally provided with a plurality of subchambers which are sequentially connected through the central fiber, the subchambers are used for receiving light source beams emitted by the first light source component and/or the second light source component and converting the light source beams into laser beams with corresponding wavelengths, the first output device is used for receiving and emitting the laser beams generated by the composite resonant cavity, and the second output device is used for receiving and emitting back reflection light in the central fiber. The technical scheme of the invention realizes stable output of multiple wavelengths, improves the nonlinear effect threshold value and realizes higher output power level.

Description

Multi-wavelength laser

Technical Field

The invention relates to the technical field of lasers, in particular to a multi-wavelength laser.

Background

As the human society enters an informatization age, it has been difficult for conventional communication technologies to meet such a rapidly growing communication capacity demand, and dense wavelength division multiplexing (DENSE WAVELENGTH Division Multiplexing, DWDM) technologies can transmit multiple signals of different wavelengths on the same optical fiber, thereby greatly improving transmission capacity.

The multi-wavelength fiber laser has the advantages of stable performance, multi-wavelength output, low cost, fiber compatibility and wide tunable range, and has very important application in the fields of fiber communication systems, fiber sensing, spectrum analysis and the like, thereby being favored by vast scientific and technological workers and various large laser manufacturers.

In the prior art, a mode of realizing multi-wavelength laser emission by a multi-wavelength fiber laser is to inhibit mode competition of a gain medium by designing a special structure. The mode is characterized in that the gain of the erbium-doped fiber is uniformly widened at room temperature, so that mode competition exists in the laser, the laser output with multiple wavelengths can not be stably established, and the output power is low.

Disclosure of Invention

The invention mainly aims to provide a multi-wavelength laser, and aims to solve the technical problems of poor stability and lower output power of a multi-wavelength laser emission mode in the prior art.

In order to achieve the above objective, the present invention provides a multi-wavelength laser, which includes a first output device, a cladding light filter, a first light source assembly, a composite resonant cavity, a second light source assembly, and a second output device sequentially connected through a central fiber;

the composite resonant cavity is internally provided with a plurality of subchambers which are sequentially connected through the central fiber, and the subchambers are used for receiving light source light beams emitted by the first light source component and/or the second light source component and converting the light source light beams into laser light beams with corresponding wavelengths;

The first output device is used for receiving and emitting the laser beam generated by the composite resonant cavity, and the second output device is used for receiving and emitting the retro-reflection light in the central fiber.

In an embodiment, the sub-cavity includes two opposite fiber gratings and an active fiber disposed between the two fiber gratings, where two ends of the active fiber are connected to the two fiber gratings through the central fiber, respectively.

In one embodiment, one of the two fiber gratings is a high reflection grating, and the other is a low reflection grating;

The high reflective grating is arranged between the active optical fiber and the second output device, and the low reflective grating is arranged between the active optical fiber and the first output device.

In one embodiment, the high reflection grating has a reflectivity of greater than or equal to 99.5% and the low reflection grating has a reflectivity of less than 15%.

In an embodiment, the central wavelengths of the two corresponding fiber gratings in the sub-cavities are the same, and the central wavelengths of the plurality of sub-cavities corresponding to the second output device to the first output device are sequentially increased.

In one embodiment, the active optical fiber is a rare earth ion doped optical fiber, and the rare earth ions include one or more of erbium ions, ytterbium ions and neodymium ions.

In one embodiment, the subchamber is removably coupled to the central fiber.

In one embodiment, the first light source assembly includes:

a plurality of first pump sources;

The first beam combining end of the reverse beam combiner is connected with the composite resonant cavity, and the first branch end of the first composite resonant cavity is respectively connected with a plurality of first pumping sources and the cladding light filter.

In one embodiment, the second light source assembly includes:

a plurality of second pump sources;

The second beam combining end of the forward beam combiner is connected with the composite resonant cavity, and the second branch end of the forward beam combiner is respectively connected with a plurality of second pump sources and the second output device.

In an embodiment, an end cap is provided at the output end of the first output device and/or the second output device, an antireflection film is provided on the end cap, and a texturing area is provided inside the first output device and/or the second output device.

According to the technical scheme, the multiple independent subchambers are formed in the optical path structure in the composite resonant cavity, the frequency of the incoming light beams is selected through the subchambers, different subchambers correspondingly form laser beams with different wavelength bands, the phenomenon of same-band pumping exists in the laser beams with multiple wavelengths, the competition of light with adjacent wavelengths on the inversion particle number can be enhanced, and therefore stable output with multiple wavelengths is achieved. Meanwhile, the laser beams with multiple wavelengths are introduced, so that the nonlinear action intensity in the optical fiber is effectively reduced, the effective action length of nonlinear effects is shortened, the nonlinear effect threshold is improved, and a higher output power level is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a multi-wavelength laser according to the present invention;

FIG. 2 is a schematic structural diagram of a first embodiment of a composite resonant cavity in a multi-wavelength laser according to the present invention;

FIG. 3 is a schematic structural diagram of a second embodiment of a composite resonant cavity in a multi-wavelength laser according to the present invention;

Fig. 4 is a schematic structural diagram of a third embodiment of a composite resonant cavity in a multi-wavelength laser according to the present invention.

Reference numerals illustrate:

10. The light source comprises a first output device, a 20 cladding light filter, a 30 first light source component, a 31 reverse beam combiner, a 32 first pumping source, a 40 second light source component, a 41 forward beam combiner, a 42 second pumping source, a 50 composite resonant cavity, a 51 high reflection grating, a 52 active optical fiber, a 53 low reflection grating and a 60 second output device.

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and rear are referred to in the embodiments of the present invention), the directional indications are merely used to explain the relative positional relationship, movement conditions, and the like between the components in a specific posture, and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if "and/or" and/or "are used throughout, the meaning includes three parallel schemes, for example," a and/or B "including a scheme, or B scheme, or a scheme where a and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.

The invention provides a multi-wavelength laser.

Referring to fig. 1, in an embodiment of the present invention, the multi-wavelength laser includes a first follower 10, a cladding light filter 20, a first light source assembly 30, a composite resonant cavity 50, a second light source assembly 40, and a second follower 60 sequentially connected through a central fiber, wherein the composite resonant cavity 50 has a plurality of subchambers sequentially connected through the central fiber, the subchambers are configured to receive a light source beam emitted by the first light source assembly 30 and/or the second light source assembly 40 and convert the light source beam into a laser beam with a corresponding wavelength, the first follower 10 is configured to receive and emit the laser beam generated by the composite resonant cavity 50, and the second follower 60 is configured to receive and emit a retro-reflection light in the central fiber.

The first follower 10, the cladding light filter 20, the first light source assembly 30, the composite resonant cavity 50, the second light source assembly 40 and the second follower 60 are serially connected through the central fibers in sequence to form a light path. Referring to fig. 1, in this embodiment, the first output device 10, the cladding light filter 20, the first light source assembly 30, the composite resonant cavity 50, the second light source assembly 40 and the second output device 60 are sequentially arranged from right to left. The laser beam is emitted from the right end of the composite resonator 50, enters the left end of the first follower 10 along the center fiber, and finally is emitted from the right end of the first follower 10.

The first and second light source modules 30 and 40 inject light source beams into the composite resonant cavity 50. The light source beams respectively enter the plurality of subchambers along the light paths. The subchamber can convert the incident light source beam into a laser beam to be emitted rightward.

In this embodiment, each sub-cavity has a unique corresponding wavelength, that is, after the light source beam enters the sub-cavity, the sub-cavity can generate a laser beam with a corresponding wavelength. The greater the number of subchambers, the more laser beams of different wavelengths can be generated in the composite resonant cavity 50.

For example, when the number of subchambers is two, then the composite resonant cavity 50 is capable of generating laser beams of two different wavelengths, when the number of subchambers is three, then the composite resonant cavity 50 generates laser beams of three different wavelengths, and so on.

The laser beam also needs to pass through a cladding filter 20 before entering the first output 10 from the composite cavity 50. The cladding light filter 20 is obtained by carrying out CO ₂ laser etching on a passive optical fiber with the diameter of a fiber core, the diameter of a cladding layer and the numerical aperture of the fiber core of 50/400/0.12, and is used for effectively filtering cladding light from forward transmission or reverse transmission, and the filtering efficiency of the cladding light is more than or equal to 98%.

It should be noted that, the laser beam is transmitted from left to right along the central fiber and finally exits from the first output device 10, and the laser beam is transmitted in the forward direction in the process. In some cases, the laser beam may be affected by the external or internal environment or may be related to the characteristics of the target material, and when the laser beam irradiates the target, some of the laser beam may be reflected back, and transmitted from right to left along the central fiber, forming a retro-reflection. These retro-reflections may under certain conditions be re-coupled into the laser interior and amplified, which may cause damage to the laser system.

Therefore, in this embodiment, the second output device 60 is added at the leftmost end of the optical path of the central fiber, and the reflected back reflection light is emitted from the left end of the second output device 60 through the second output device 60. Thereby avoiding back reflections into the laser.

According to the technical scheme, a plurality of independent subchambers are formed in the composite resonant cavity 50 in the optical path structure, the frequency of the incoming light beams is selected through the subchambers, different subchambers correspondingly form laser beams with different wavelength bands, the phenomenon of same-band pumping exists in the laser beams with the plurality of wavelengths, the competition of light with adjacent wavelengths on the inversion particle number can be enhanced, and therefore stable output with multiple wavelengths is achieved. Meanwhile, the laser beams with multiple wavelengths are introduced, so that the nonlinear action intensity in the optical fiber is effectively reduced, the effective action length of nonlinear effects is shortened, the nonlinear effect threshold is improved, and a higher output power level is realized.

In an embodiment of the present invention, the sub-cavity includes two opposite fiber gratings and an active fiber 52 disposed between the two fiber gratings, where two ends of the active fiber 52 are connected to the two fiber gratings through the central fiber, respectively.

The plurality of subchambers are connected in series through a central fiber. Please refer to fig. 1. In one subchamber, one fiber grating is disposed on each of the left and right sides of the active fiber 52.

Referring to fig. 2, in the present embodiment, a1, a2, a3, and a4 are sequentially arranged in order from left to right, where a1 and a2 form a first sub-cavity, the active optical fiber 52 is used for reflecting the light beam emitted from the light source assembly, and the light beam frequently passes through the active optical fiber 52 between a1 and a2, so as to enhance the laser. Similarly, a3 and a4 form a second sub-cavity.

When the number of the fiber gratings is larger, the number of the subchambers is larger. Referring to fig. 3, a plurality of fiber gratings, a1, a2, a3, a4, a5, a6, are sequentially arranged from left to right, and the active optical fibers 52 are respectively disposed between a1 and a2, between a3 and a4, and between a5 and a6, so that a first sub-cavity is formed between a1 and a2, a second sub-cavity is formed between a3 and a4, and a third sub-cavity is formed between a5 and a 6.

Similarly, referring to fig. 4, a plurality of fiber gratings a1, a2, a3, a4, a5, a6, a7, a8 are sequentially arranged from left to right to form sub-cavities between a1 and a2, between a3 and a4, between a5 and a6, and between a7 and a8, respectively, and so on.

Taking the leftmost subchamber as an example, the fiber grating to the left of the active fiber 52 is defined as the left grating and the fiber grating to the right of the active fiber 52 is defined as the right grating. The left end of the left grating is connected with the right end of the second light source assembly 40, the right end of the left grating is connected with the left end of the active optical fiber 52, the right end of the active optical fiber 52 is connected with the left end of the right grating, the right end of the right grating is connected with the left end of the left grating in the next subcavity, and so on until the right end of the right grating in the subcavity positioned at the rightmost side is connected with the left end of the second light source assembly 40.

The active optical fiber 52 in this embodiment may be a high gain doped active optical fiber 52, that is, a rare earth ion doped optical fiber, where the rare earth ions include one or more of erbium ions, ytterbium ions, and neodymium ions. In addition, the active optical fiber 52 may include a single component of at least one of Yb ³⁺、Er³⁺、Tm³⁺、Ho³⁺ and Dy ³⁺, a double component, or a combination of more than two components.

The active optical fiber 52 is used to enhance the light source beam. After the light source component transmits the light source beam into the subchamber, the wavelength meeting the Bragg condition of the fiber grating is reflected, and the rest wavelengths are transmitted continuously through the fiber grating. Thus, the light source beam is first reflected by one of the left or right gratings, so that the light source beam passes through the active optical fiber 52 and then impinges on the other, so as to be reflected again and pass through the active optical fiber 52 again. The light source beam is finally formed after repeated times of reciprocation the laser beam exits through the right grating.

In this embodiment, the structural parameters of the active fiber 52 may be 20/400/0.065, an absorption coefficient of about 0.38dB/m, or 25/400/0.065, and an absorption coefficient of 0.53dB/m. The fiber bragg grating can be obtained by adopting a hydrogen-carrying mask plate photoetching process. In this embodiment, the center wavelength of the fiber bragg grating may be set in the range of 1030nm to 2020nm, and the spectral bandwidth is 1 to 4nm. For example, the center wavelengths of the fiber gratings in the plurality of sub-cavities are set to 1050nm, 1060nm, 1070nm, respectively, so that laser beams having wavelengths of 1050nm, 1060nm, 1070nm are finally output from the first outputter 10, respectively.

In one embodiment of the present invention, one of the two fiber gratings is a high reflection grating 51, the other is a low reflection grating 53, the high reflection grating 51 is disposed between the active fiber 52 and the second output device 60, and the low reflection grating 53 is disposed between the active fiber 52 and the first output device 10.

In this embodiment, the low reflection grating 53 indicates that the reflectivity of the fiber grating is low, and the high reflection grating 51 indicates that the reflectivity of the fiber grating is high. For example, in a subchamber, the reflectivity of the low reflective grating 53 may be set to less than 15% with a spectral bandwidth of 3nm, and the reflectivity of the high reflective grating 51 may be set to greater than or equal to 99.5% with a spectral bandwidth of 1nm.

Referring to fig. 1, the laser beam is transmitted from left to right into the first output device 10. Thus, the left grating in the subchamber is set to the low reflective grating 53 and the right grating is set to the high reflective grating 51. The high reflection grating 51 is used to reflect the light beam back into the active optical fiber 52 to increase the number of passes of the light beam in the active optical fiber 52 and thus enhance the laser beam. The low reflectivity grating 53 has a low reflectivity so as to allow a portion of the beam to pass through, forming a laser beam to pass to the right.

It will be appreciated that the positions of the low reflective grating 53 and the high reflective grating 51 include, but are not limited to, the above-described manner, and when the transmission direction of the laser beam is changed, the positions may be exchanged correspondingly according to the transmission direction of the laser beam.

In addition, the central wavelengths of the two corresponding fiber gratings in the sub-cavities are the same, and the central wavelengths of the plurality of sub-cavities corresponding to the direction from the second output device 60 to the first output device 10 are sequentially increased.

The laser beam wavelength formed in each subchamber is different. The central wavelengths of the two corresponding fiber bragg gratings in each subchamber are the same. Referring to fig. 2, for example, when two subchambers are provided, the center wavelengths of the fiber gratings in the subchambers are 1070nm and 1080nm in sequence from left to right, referring to fig. 3, for example, when three subchambers are provided, the center wavelengths of the fiber gratings in the subchambers are 1060nm, 1070nm and 1080nm in sequence from left to right, and referring to fig. 4, for example, when four subchambers are provided, the center wavelengths of the fiber gratings in the subchambers are 1060nm, 1070nm, 1080nm and 1090nm in sequence from left to right. By means of the arrangement mode of sequential increment, the laser beam can pass through the optical fiber grating, and finally is transmitted to the first right-side output device 10, so that the influence of the vertical floating of the central wavelength of the optical fiber grating on the laser beam transmission is avoided.

In an embodiment of the present invention, the subchamber is detachably connected to the central fiber. Specifically, the left and right ends of the fiber grating are fused to the central fiber, and the left and right ends of the active fiber 52 are fused to the central fiber.

When the number of subchambers needs to be increased, the central fiber between the two subchambers can be cut off, and the new subchambers are welded to the central fiber between the two subchambers. In addition, when the number of the subchambers needs to be reduced, the central fibers at the left end and the right end of the subchambers are cut off, and the central fibers are welded to the subchambers at the two sides again after the subchambers are removed. Therefore, the sub-cavities can be quickly disassembled and assembled, and the compatibility of the multi-wavelength laser is improved.

In an embodiment of the present invention, the first light source assembly 30 includes a reverse beam combiner 31 and a plurality of first pump sources 32, a first beam combining end of the reverse beam combiner 31 is connected to the composite resonant cavity 50, and a first branching end of the first composite resonant cavity 50 is connected to the plurality of first pump sources 32 and the cladding light filter 20, respectively.

Referring to fig. 1, the first pump source 32 is a reverse pump source, and the second pump source 42 is a forward pump source. The two pumping modes can be used singly or in combination.

Correspondingly, the left end of the reverse beam combiner 31 is a beam combining end, the right end is a branching end, the left end of the forward beam combiner 41 is a branching end, and the right end is a beam combining end. The beam combiners may be (n+1) x 1 type beam combiners, for example, (6+1) x 1 beam combiners, where the number of first pump sources 32 is 6.

The first pump sources 32 are respectively connected with the branch ends of the backward combiner 31 through pump fibers, and the second pump sources 42 are respectively connected with the branch ends of the forward combiner 41 through pump fibers.

Referring to fig. 1, a beam combining end of the backward beam combiner 31 is connected to the composite resonant cavity 50, one branch of the branch end is connected to the cladding light filter 20 through the central fiber, and the other branches are correspondingly connected to a first pump source 32.

In an embodiment of the invention, the second light source assembly 40 includes a forward beam combiner 41 and a plurality of second pump sources 42, wherein a second beam combining end of the forward beam combiner 41 is connected to the composite resonant cavity 50, and a second branch end of the forward beam combiner 41 is respectively connected to the plurality of second pump sources 42 and the second output device 60.

Similarly, the forward beam combiner 41 is similar to the backward beam combiner 31 in structure but opposite in direction, and the number of the second pump sources 42 is 6 by using a (6+1) x 1 beam combiner.

In an embodiment of the present invention, an end cap is disposed on the output end of the first output device 10 and/or the second output device 60, an anti-reflection film is disposed on the end cap, and a roughened area is disposed inside the first output device 10 and/or the second output device 60.

In this embodiment, the optical fiber type of the output device is 50/400/0.12 passive optical fiber, referring to fig. 1, the output end of the first output device 10 is the right side end, the output end of the second output device 60 is the left side end, and the output end is welded with the quartz end cap coated with the antireflection film. The inside of the output device is provided with a frosted area which is obtained by frosted cream corrosion roughening or CO ₂ laser etching technology with corrosion characteristics and is used for realizing forward cladding light stripping and reverse return cladding light stripping.

Light from first pump source 32 and/or second pump source 42 is generated by the semiconductor and coupled out through the optical fiber. The optical output wavelength of the pump source is 915nm as an example in the embodiment, the output power of the pump source is more than or equal to 650W, and the output tail fiber is 200/220/0.22.

By modulating the injection current of the pump source, pump light with different powers can be injected into the composite resonant cavity 50, and finally the composite resonant cavity 50 is utilized to realize the output of continuous 1080nm laser.

By modulating the light injected into the pump source, the laser can realize 1080nm fiber laser output with high peak power of more than 2500W.

In the structure of the optical fiber oscillator, when the laser power density in the optical fiber is high, nonlinear effects such as stimulated Raman scattering, stimulated Brillouin scattering and the like are easy to generate, so that most of energy is transferred to Stokes light, the increase of signal optical power in the oscillator is affected, and the Stokes light transmitted in the backward direction can threaten the safety of a front-stage system. If a plurality of fiber gratings are used simultaneously in the oscillator to form the composite resonant cavity 50, not only the nonlinear action intensity in the optical fiber is effectively reduced by introducing light with a plurality of wavelengths, but also the effective action length of the nonlinear effect is shortened, and the nonlinear effect threshold is improved, so that a higher output power level of the oscillator can be realized.

The foregoing description is only exemplary embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the present invention.

Claims (10)

1. The multi-wavelength laser is characterized by comprising a first output device, a cladding light filter, a first light source assembly, a composite resonant cavity, a second light source assembly and a second output device which are sequentially connected through a central fiber;

the composite resonant cavity is internally provided with a plurality of subchambers which are sequentially connected through the central fiber, and the subchambers are used for receiving light source light beams emitted by the first light source component and/or the second light source component and converting the light source light beams into laser light beams with corresponding wavelengths;

The first output device is used for receiving and emitting the laser beam generated by the composite resonant cavity, and the second output device is used for receiving and emitting the retro-reflection light in the central fiber.

2. A multi-wavelength laser as claimed in claim 1 wherein the sub-cavity comprises two oppositely disposed fiber gratings and an active optical fiber disposed between the two fiber gratings, the active optical fiber having two ends connected to the two fiber gratings through the central fiber, respectively.

3. The multi-wavelength laser of claim 2, wherein one of the two fiber gratings is a high reflection grating and the other is a low reflection grating;

The high reflective grating is arranged between the active optical fiber and the second output device, and the low reflective grating is arranged between the active optical fiber and the first output device.

4. The multi-wavelength laser of claim 3, wherein the high reflection grating has a reflectivity of greater than or equal to 99.5% and the low reflection grating has a reflectivity of less than 15%.

5. A multi-wavelength laser as claimed in claim 2 wherein the central wavelengths of the corresponding two fibre gratings in the sub-cavities are the same, the central wavelengths of the corresponding sub-cavities increasing in sequence along the direction from the second output to the first output.

6. The multiwavelength laser of claim 2, wherein the active optical fiber is a rare earth ion doped optical fiber, the rare earth ions comprising one or more of erbium ions, ytterbium ions, neodymium ions.

7. A multi-wavelength laser as claimed in any one of claims 1 to 6 wherein the sub-cavity is detachably connected to the central fiber.

8. The multiwavelength laser of claim 1, wherein said first light source assembly comprises:

a plurality of first pump sources;

The first beam combining end of the reverse beam combiner is connected with the composite resonant cavity, and the first branch end of the first composite resonant cavity is respectively connected with a plurality of first pumping sources and the cladding light filter.

9. The multiwavelength laser of claim 1, wherein said second light source assembly comprises:

a plurality of second pump sources;

The second beam combining end of the forward beam combiner is connected with the composite resonant cavity, and the second branch end of the forward beam combiner is respectively connected with a plurality of second pump sources and the second output device.

10. The multi-wavelength laser of claim 1, wherein an end cap is provided on an output end of the first and/or second output device, an antireflection film is provided on the end cap, and a roughened region is provided inside the first and/or second output device.