A wavelength-tunable Raman fiber laser based on gain control

Abstract

The present invention discloses a wavelength-tunable Raman fiber laser based on gain control, comprising a second feedback component, a second coupling component, a gain component, a first coupling component, an output component, and a first feedback component, which are sequentially connected to form a linear cavity structure, and further comprising a second excitation component and a first excitation component. The light output by the first excitation component and the second excitation component has different central wavelengths. The present invention has a simple structure, wherein two pump lights of different central wavelengths are selected, each of which is power-amplified by an amplifying component and then coupled into a Raman gain fiber, i.e., a gain component. After the two Raman net gain spectra are superimposed on each other, Raman laser light can be emitted at the point of highest gain in the resonant cavity. Compared with traditional tunable Raman fiber lasers, there is no need for costly wavelength-tunable pump sources and tunable filters, and the resonant cavity structure is simple and compact with low loss.

Description

Technical Field

[0001] The present invention relates to the field of laser optoelectronic technology, and in particular to a wavelength tunable Raman fiber laser based on gain spectrum regulation. Background Art

[0002] 1.6-1.7μm wavelength tunable laser sources have important applications in medicine, lidar, and fiber-optic communications. However, this wavelength lies at the gain band edge of traditional erbium-doped and thulium-doped fiber lasers, making it difficult to directly output high-performance tunable laser light. Raman fiber lasers can achieve arbitrary wavelength output by selecting an appropriate pump source and Raman gain medium, making them an effective technology for achieving 1.6-1.7μm wavelength tunable laser sources.

[0003] Currently, there are two main methods for achieving wavelength tunability in Raman lasers: one is to use a wavelength-tunable pump source to directly control the central wavelength of the cavity lasing laser, and the other is to adjust the laser cavity loss through a tunable filter. However, compared to a fixed-wavelength pump source, a wavelength-tunable pump source is more complex and expensive to prepare. Furthermore, it places higher demands on amplifier performance, ultimately leading to a complex and expensive system.

[0004] Tunable filters are typically high-loss, expensive components. Inserting them into a laser cavity can increase the laser threshold and cost, further increasing the pump power and fabrication cost requirements for Raman lasers. Therefore, the search for a low-cost, readily available technology for realizing wavelength-tunable Raman fiber lasers remains urgent. Summary of the Invention

[0005] To solve at least one of the above technical problems, the present invention provides a wavelength-tunable Raman fiber laser based on gain control, comprising a second feedback component, a second coupling component, a gain component, a first coupling component, an output component, and a first feedback component, which are sequentially connected to form a linear cavity structure. The laser also comprises a second excitation component, wherein the second excitation component and the second coupling component are sequentially connected to couple the light of the second excitation component into the linear cavity structure; and a first excitation component, wherein the first excitation component and the first coupling component are sequentially connected to couple the light of the first excitation component into the linear cavity structure.

[0006] The lights output by the first excitation component and the second excitation component have different central wavelengths.

[0007] It also includes a second amplifying component, wherein the second excitation component, the second amplifying component, and the second coupling component are connected in sequence to achieve light coupling of the second excitation component into the linear cavity structure, and / or it also includes a first amplifying component, wherein the first excitation component, the first amplifying component, and the first coupling component are connected in sequence to achieve light coupling of the first excitation component into the linear cavity structure.

[0008] The first excitation component and the second excitation component are pump sources for providing pump light. The first excitation component and the second excitation component are one or both of a fiber laser, a semiconductor laser, or a solid-state laser.

[0009] The first feedback component and the second feedback component are one or both of a broadband fiber loop mirror, a broadband reflection grating, and a broadband reflection mirror, and are used to reflect the laser in the linear cavity structure to form a resonant cavity.

[0010] The first amplifying component and the second amplifying component are power amplifiers for increasing the optical power output by the first excitation component and the second excitation component, and are one or both of optical fiber amplifiers, semiconductor optical amplifiers, and solid-state optical amplifiers.

[0011] The first coupling component and the second coupling component are one or both of an optical fiber wavelength division multiplexer and a dichroic mirror, and are used to couple the light output by the first excitation component and the second excitation component into the resonant cavity.

[0012] The gain component can be a dispersion-shifted / compensated fiber, a highly nonlinear fiber, a quartz fiber, a chalcogenide fiber, or a fluoride fiber, and is used to generate Raman laser light.

[0013] The gain component is one of dispersion-shifted / compensating optical fiber, highly nonlinear optical fiber, quartz optical fiber, chalcogenide optical fiber, and fluoride optical fiber.

[0014] The output component is a fiber coupler or a beam splitter, which is used to output the laser in the resonant cavity to the outside of the cavity.

[0015] Compared with the existing technology, the advantages of the present invention are: the present invention has a simple structure, adopts two pump lights with fixed central wavelengths as pump sources, and realizes the tuning of the Raman laser center wavelength by distributing the two pump light powers. Compared with traditional tunable Raman fiber lasers, it does not require expensive wavelength tunable pump sources and tunable filters, and the resonant cavity structure is simple and compact with low loss.

[0016] The principle of the present invention is: two pump lights with different central wavelengths are selected and power amplified by an amplifier component and then coupled into a Raman gain fiber, i.e., a gain component. After the two Raman net gain spectra are superimposed on each other, Raman lasers can be emitted at the point with the strongest gain in the resonant cavity.

[0017] The present invention can regulate the intensity of the Raman gain spectrum of each of the two pump lights by changing the power of the two pump lights. At this time, the peak value of the superimposed Raman net gain spectrum in the resonant cavity changes with the pump light power, and the central wavelength of the laser with the strongest gain can also change with the change of power. Ultimately, the central wavelength of the output Raman laser can be tuned by regulating the Raman gain spectrum. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 The tuning situation of the output laser center wavelength of the Raman laser as the power ratio of the two pump lasers changes;

[0020] Figure numerals: 1 - first feedback component; 2 - output component; 3 - first excitation component; 4 - first amplification component; 5 - first coupling component; 6 - gain component; 7 - second coupling component; 8 - second amplification component; 9 - second excitation component; 10 - second feedback component. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the present invention and thus more clearly define the scope of protection claimed in the present invention, the present invention is described in detail below with respect to certain specific embodiments of the present invention. It should be noted that the following are only certain specific embodiments of the present invention, which are only part of the embodiments of the present invention. The specific and direct description of the relevant structures is only for the convenience of understanding the present invention, and the specific features do not necessarily and directly limit the scope of implementation of the present invention.

[0022] Referring to the accompanying drawings, the present invention adopts the following technical solution: a wavelength-tunable Raman fiber laser based on gain control, wherein a second feedback component 10, a second coupling component 7, a gain component 6, a first coupling component 5, an output component 2 and a first feedback component 1 are connected in sequence to form a linear cavity structure, and further includes a second excitation component 9, wherein the second excitation component 9 and the second coupling component 7 are connected in sequence to achieve coupling of light from the second excitation component 9 into the linear cavity structure; and further includes a first excitation component 3, wherein the first excitation component 3 and the first coupling component 5 are connected in sequence to achieve coupling of light from the first excitation component 3 into the linear cavity structure.

[0023] The light output by the first excitation component 3 and the second excitation component 9 has different central wavelengths.

[0024] In this embodiment, a second amplifying component 8 is further included, and the second excitation component 9, the second amplifying component 8, and the second coupling component 7 are connected in sequence to realize the light coupling of the second excitation component 9 into the linear cavity structure. A first amplifying component 4 is also included, and the first excitation component 3, the first amplifying component 4, and the first coupling component 5 are connected in sequence to realize the light coupling of the first excitation component 3 into the linear cavity structure.

[0025] The signal terminal of the first amplifying component 4 is connected to the output component 2, the common terminal is connected to the gain component 6, and the pump terminal is connected to the first excitation component 3; the signal terminal of the second amplifying component 8 is connected to the second feedback component 10, the common terminal is connected to the gain component 6, and the pump terminal is connected to the second excitation component 9.

[0026] The first excitation component 3 and the second excitation component 9 are pump sources for providing pump light. The first excitation component 3 and the second excitation component 9 are one or both of a fiber laser, a semiconductor laser, or a solid-state laser.

[0027] The first feedback component 1 and the second feedback component 10 are one or both of a broadband fiber loop mirror, a broadband reflection grating, or a broadband reflector, which provide high feedback and are used to reflect the laser in the linear cavity structure to form a resonant cavity.

[0028] The first amplifying component 4 and the second amplifying component 8 are power amplifiers for increasing the optical power output by the first excitation component 3 and the second excitation component 9. They are one or both of optical fiber amplifiers, semiconductor optical amplifiers, and solid-state optical amplifiers.

[0029] The first coupling component 5 and the second coupling component 7 are one or both of an optical fiber wavelength division multiplexer or a dichroic mirror, and are used to couple the light output by the first excitation component 3 and the second excitation component 9 into the resonant cavity.

[0030] The gain component 6 can be a dispersion-shifted / compensated fiber, a highly nonlinear fiber, a quartz fiber, a chalcogenide fiber, or a fluoride fiber, and is used to generate Raman laser light.

[0031] The gain component 6 is one of dispersion-shifted / compensating optical fiber, highly nonlinear optical fiber, quartz optical fiber, chalcogenide optical fiber, and fluoride optical fiber.

[0032] The output component 2 is a fiber coupler or a beam splitter, which is used to output the laser in the resonant cavity to the outside of the cavity.

[0033] In this embodiment, suitable first and second excitation components 9, first and second amplification components 8, gain component 6, first and second feedback components 10, and output component 2 are selected to form a laser resonant cavity through optical fiber fusion or optical path construction. The power of the first excitation component 3 is first increased to its laser, and then the power of the second excitation component 9 is adjusted to change the peak position of the net gain spectrum in the laser resonant cavity. Finally, the center wavelength of the laser in the laser resonant cavity changes with the power ratio of the first and second excitation components 9 pumped, thereby achieving wavelength tunability.

[0034] like Figure 2As shown, the first excitation component 3 is a 1560nm fiber laser, and the second excitation component 9 is a 1561.1nm fiber laser. The first and second amplification components 8 are two erbium-doped fiber amplifiers with a maximum power of 1.1W. The first and second coupling components 7 are two 1550 / 1650nm wavelength division multiplexers. The gain component 6 is a 1km section of dispersion-shifted fiber. The first and second reflection components are high-reflectivity broadband fiber mirrors composed of two 50:50 1650nm fiber couplers. The output component 2 is a 10:90 1650nm fiber coupler, with the 10% end used for laser output.

[0035] The above devices are in accordance with Figure 1 The structure is fused using a fiber fusion splicer to form a linear cavity Raman fiber laser, which increases the power of the erbium-doped fiber amplifier. When the output power ratio of the two amplifiers is adjusted from 0.15 to 3, the laser output spectrum can be tuned from 1673nm to 1681nm, realizing wavelength tunability.

[0036] The present invention has a simple structure and adopts two pump lights with fixed central wavelengths as pump sources. The central wavelength of the Raman laser is tuned by distributing the power of the two pump lights. Compared with traditional tunable Raman fiber lasers, the invention does not require expensive wavelength tunable pump sources and tunable filters. The resonant cavity structure is simple and compact, and the loss is low.

[0037] The principle of the present invention is: two pump lights with different central wavelengths are selected and power amplified by an amplifier component and then coupled into the Raman gain fiber, i.e., the gain component 6. After the two Raman net gain spectra are superimposed on each other, Raman laser can be emitted at the point with the strongest gain in the resonant cavity.

[0038] The present invention can regulate the intensity of the Raman gain spectrum of each of the two pump lights by changing the power of the two pump lights. At this time, the peak value of the superimposed Raman net gain spectrum in the resonant cavity changes with the pump light power, and the central wavelength of the laser with the strongest gain can also change with the change of power. Ultimately, the central wavelength of the output Raman laser can be tuned by regulating the Raman gain spectrum.

[0039] The above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A wavelength-tunable Raman fiber laser based on gain control, characterized in that: The second feedback component (10), the second coupling component (7), the gain component (6), the first coupling component (5), the output component (2) and the first feedback component (1) are sequentially connected to form a linear cavity structure. It also includes a second excitation component (9), wherein the second excitation component (9) and the second coupling component (7) are connected in sequence to achieve coupling of light from the second excitation component (9) into the linear cavity structure; It also includes a first excitation component (3), wherein the first excitation component (3) and a first coupling component (5) are connected in sequence to achieve coupling of light from the first excitation component (3) into the linear cavity structure; The light output by the first excitation component (3) and the second excitation component (9) has different central wavelengths.

2. The wavelength tunable Raman fiber laser based on gain control according to claim 1, characterized in that: The invention also includes a second amplifying component (8), wherein the second excitation component (9), the second amplifying component (8), and the second coupling component (7) are sequentially connected to realize light coupling of the second excitation component (9) into the linear cavity structure, and / or further includes a first amplifying component (4), wherein the first excitation component (3), the first amplifying component (4), and the first coupling component (5) are sequentially connected to realize light coupling of the first excitation component (3) into the linear cavity structure.

3. The wavelength tunable Raman fiber laser based on gain control according to claim 1 or 2, characterized in that: The first excitation component (3) and the second excitation component (9) are pump sources for providing pump light. The first excitation component (3) and the second excitation component (9) are one or both of a fiber laser, a semiconductor laser, or a solid-state laser.

4. The wavelength tunable Raman fiber laser based on gain control according to claim 1 or 2, characterized in that: The first feedback component (1) and the second feedback component (10) are one or both of a broadband fiber ring mirror, a broadband reflection grating, and a broadband reflection mirror, and are used to reflect the laser in the linear cavity structure to form a resonant cavity.

5. The wavelength tunable Raman fiber laser based on gain control according to claim 2, characterized in that: The first amplifying component (4) and the second amplifying component (8) are power amplifiers for increasing the optical power output by the first excitation component (3) and the second excitation component (9), and are one or both of optical fiber amplifiers, semiconductor optical amplifiers, and solid-state optical amplifiers.

6. The wavelength tunable Raman fiber laser based on gain control according to claim 1 or 2, characterized in that: The first coupling component (5) and the second coupling component (7) are one or both of an optical fiber wavelength division multiplexer or a dichroic mirror, and are used to couple the light output by the first excitation component (3) and the second excitation component (9) into the resonant cavity.

7. The wavelength tunable Raman fiber laser based on gain control according to claim 1 or 2, characterized in that: The gain component (6) can be a dispersion shifted / compensated optical fiber, a highly nonlinear optical fiber, a quartz optical fiber, a chalcogenide optical fiber, or a fluoride optical fiber, and is used to generate Raman laser light.

8. The wavelength tunable Raman fiber laser based on gain control according to claim 1 or 2, characterized in that: The output component (2) is a fiber coupler or a beam splitter, and is used to output the laser light in the resonant cavity to the outside of the cavity.

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