A wavelength-switchable pulsed fiber laser in the near-infrared band
A wavelength-selectable thulium-doped fiber laser with a photonic crystal fiber structure addresses the issue of fixed wavelengths by using a tunable filter and polarization controllers to switch output bands, enhancing its applicability in advanced optical communication systems.
Patent Information
- Application Number
- CN202210705539.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-21
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2042-06-21
AI Technical Summary
Many thulium-doped fiber lasers lack the ability to select output wavelengths according to working requirements, limiting their application in wavelength division multiplexing and other advanced optical communication technologies.
A wavelength-selectable thulium-doped fiber laser utilizing polarization-maintaining photonic crystal fiber, incorporating a 793-nm cladding pump, combiner, rare earth metal thulium-doped fiber, optical fiber circulator, highly nonlinear fiber, fiber polarizers, and polarization controllers to form a tunable filter, enabling wavelength switching through adjustments in the laser cavity.
The laser achieves wavelength-switchable output by leveraging the ultra-high birefringence of the photonic crystal fiber and optimized structure, allowing selective laser operation across different bands for applications in wavelength division multiplexing and space optical communication.
Smart Images
Figure CN115036780B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a thulium-doped fiber laser with selectable wavelength based on polarization-maintaining photonic crystal fiber, and belongs to the fields of optical fiber communication, optical fiber devices and instruments. Background Art
[0002] Since the advent of optical fiber in 1970, optical communication technology using optical fiber as a transmission medium has developed rapidly. Fiber lasers have important application value in modern optical fiber communications due to their small size, high efficiency, and good beam quality. Using rare earth-doped optical fiber as a gain medium is an important condition for achieving fiber laser lasing. Currently, the commonly used fiber laser that can be used as a communication light source is an erbium-doped fiber laser with an output laser band of 1530nm to 1565nm. With the gradual saturation of the C-band channel, since the discovery of thulium and holmium elements in 1879, the development of near-infrared fiber lasers that use thulium-doped fiber and holmium-doped fiber to achieve 2000nm laser lasing has become an important direction for the development of future optical communication technology.
[0003] In order to improve communication capacity and meet the requirements of the growing large-capacity communication network, wavelength-switchable fiber lasers can achieve the selective output of single lasers of different wavelengths by the same laser, and can also achieve the selective simultaneous lasing of lasers of different wavelengths. It has very important application value in the field of dense wavelength division multiplexing and has become a hot topic of current research. Summary of the invention
[0004] The main technical problem solved by the present invention is that many thulium-doped fiber lasers currently cannot select output wavelengths according to working requirements, and a thulium-doped fiber laser with selectable wavelength based on polarization-maintaining photonic crystal fiber is proposed.
[0005] A wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber comprises a 793-nanometer cladding pump, a 793-nanometer / 2000-nanometer cladding pump combiner, a rare earth metal thulium-doped fiber, an optical fiber circulator, a highly nonlinear optical fiber, a first optical fiber polarizer, a polarization-maintaining photonic crystal fiber, a 50:50 optical fiber coupler, a first polarization controller, a second polarization controller, a second optical fiber polarizer, a third polarization controller, and a 90:10 optical fiber coupler.
[0006] The 793 nm cladding pump is connected to one end of the 793 nm / 2000 nm cladding pump combiner, the other end of the 793 nm / 2000 nm cladding pump combiner is connected to one end of the rare earth metal thulium doped fiber, the other end of the rare earth metal thulium doped fiber is connected to port 1 of the fiber circulator, port 2 of the fiber circulator is connected to the high nonlinear fiber, the other end of the high nonlinear fiber is connected to the fiber polarizer 1, the other end of the fiber polarizer 1 is connected to the polarization-maintaining photonic crystal fiber, the other end of the polarization-maintaining photonic crystal fiber is connected to the 50:50 fiber coupler, The other end of the 50:50 fiber coupler is respectively connected to the two ends of polarization controller one to form a loop, the 3 ports of the fiber circulator are connected to polarization controller two, the other end of polarization controller two is connected to fiber polarizer two, the other end of fiber polarizer two is connected to polarization controller three, the other end of polarization controller three is connected to a 90:10 fiber coupler, the other end of the 90:10 fiber coupler is connected to a 793 nm / 2000 nm cladding pump combiner to form a loop, and the port of the 90:10 fiber coupler serves as the output port of the entire laser.
[0007] The effects of the present invention are as follows:
[0008] A wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber is proposed. The laser uses a fiber polarizer, a polarization-maintaining photonic crystal fiber, a 50:50 fiber coupler, and a polarization controller to form a tunable filter, and uses a nonlinear polarization rotation structure to suppress mode competition in the laser cavity. The wavelength interval of the laser is determined by the length and birefringence of the polarization-maintaining photonic crystal fiber, the cavity loss is determined by the length of the high nonlinear fiber and the length of the polarization-maintaining photonic crystal fiber, and the switching of the output band is achieved by adjusting the polarization controller in the laser cavity.
[0009] In order to achieve wavelength-switchable laser output, commonly used auxiliary optical devices include fiber Bragg gratings, polarization-maintaining fiber Sagnac interferometers, Michelson interferometers, etc., which make the specific wavelength in the laser cavity oscillate. The polarization-maintaining photonic crystal fiber used in the present invention utilizes the ultra-high birefringence performance caused by its special structure, and changes the polarization state of the laser in the fiber laser cavity, combined with the optimization design and innovation of the fiber laser structure, to achieve the switching of the output laser band. This laser will play an important role in the fields of wavelength division multiplexing, fiber laser sensing, space optical communication, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 The utility model relates to a wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber.
[0011] FIG2( a ) shows the output spectrum of the filter at different polarization states after adjusting the polarization controller 1. ...
[0012] FIG2( b ) shows the output spectrum of the filter at different polarization states after adjusting the polarization controller 1. ...
[0013] Figure 3 Schematic diagram of output band switching of a wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber. DETAILED DESCRIPTION
[0014] The present invention is further described below in conjunction with the accompanying drawings and embodiments.
[0015] Obviously, many modifications and changes made by those skilled in the art based on the purpose of the present invention belong to the protection scope of the present invention.
[0016] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when an element or component is said to be "connected" to another element or component, it may be directly connected to the other element or component, or there may be an intermediate element or component. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.
[0017] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art.
[0018] To facilitate the understanding of the embodiments, further explanations will be given below, and each embodiment does not constitute a limitation of the present invention.
[0019] Example 1: Figure 1 , Figure 2(a), Figure 2(b) and Figure 3 As shown, a wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber includes a 793-nanometer cladding pump 01, a 793-nanometer / 2000-nanometer cladding pump combiner 02, a rare-earth metal thulium-doped fiber 03, an optical fiber circulator 04, a highly nonlinear optical fiber 05, an optical fiber polarizer 1 06, a polarization-maintaining photonic crystal fiber 07, a 50:50 optical fiber coupler 08, a polarization controller 1 09, a polarization controller 2 10, an optical fiber polarizer 2 11, a polarization controller 3 12, and a 90:10 optical fiber coupler 13.
[0020] The 793 nm cladding pump 01 is connected to one end of the 793 nm / 2000 nm cladding pump combiner 02, the other end 021 of the 793 nm / 2000 nm cladding pump combiner 02 is connected to one end of the rare earth metal thulium doped fiber 03, the other end 031 of the rare earth metal thulium doped fiber 03 is connected to port 1 of the fiber circulator 04, port 2 041 of the fiber circulator 04 is connected to the high nonlinear fiber 05, the other end 051 of the high nonlinear fiber 05 is connected to the fiber polarizer 06, the other end 061 of the fiber polarizer 06 is connected to the polarization-maintaining photonic crystal fiber 07, the other end 071 of the polarization-maintaining photonic crystal fiber 07 is connected to the 50:50 fiber coupler 08, 50 The other ends 081 and 082 of the 50:10 fiber coupler 08 are respectively connected to the two ends of the polarization controller 1 09 to form a loop, the 3-port 042 of the fiber circulator 04 is connected to the polarization controller 2 10, the other end 101 of the polarization controller 2 10 is connected to the fiber polarizer 2 11, the other end 111 of the fiber polarizer 2 11 is connected to the polarization controller 3 12, the other end 121 of the polarization controller 3 12 is connected to the 90:10 fiber coupler 13, the other end of the 90:10 fiber coupler 13 is connected to the 793 nm / 2000 nm cladding pump combiner 02 through 022 to form a loop, and the port 131 of the 90:10 fiber coupler 13 serves as the output port of the entire laser.
[0021] Figure 2(a) shows the transmission spectrum of a filter of a wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber after adjusting the polarization controller 109. The transmission spectrum of the filter is determined by the birefringence index of the polarization-maintaining photonic crystal fiber, the length of the polarization-maintaining photonic crystal fiber, and the polarization controller 1. When the birefringence index and length of the polarization-maintaining photonic crystal fiber are fixed values, the output spectrum of the filter under different polarization states can be obtained by adjusting the polarization controller 1.
[0022] Figure 2(b) shows the transmission spectrum of a filter of a wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber after adjusting the polarization controller 109. The transmission spectrum of the filter is determined by the birefringence index of the polarization-maintaining photonic crystal fiber, the length of the polarization-maintaining photonic crystal fiber, and the polarization controller 1. When the birefringence index and length of the polarization-maintaining photonic crystal fiber are fixed values, the output spectrum of the filter under different polarization states can be obtained by adjusting the polarization controller 1.
[0023] Figure 3 The schematic diagram of the output band switching of a wavelength-selectable thulium-doped fiber laser based on polarization-maintaining photonic crystal fiber is shown in FIG. By adjusting polarization controller 1, polarization controller 2, and polarization controller 3, single-wavelength output of a switchable band can be achieved. The switchable wavelength intervals include Δλ1, Δλ2, and Δλ3.
[0024] The 50:50 fiber coupler 08 is a 1×2 coupler with a splitting ratio of 50:50.
[0025] The 90:10 fiber coupler 13 is a 1×2 coupler with a splitting ratio of 90:10. The end of the 90:10 fiber coupler 13 with 10% output power is used as the output port of the entire laser.
[0026] The optical path transmission direction of the optical fiber circulator 04 is clockwise. Light can only be transmitted from port 1 to port 2 of the optical fiber circulator 04, and then from port 2 to port 3. The transmission direction is irreversible.
[0027] As described above, the embodiments of the present invention are described in detail, but it is obvious to those skilled in the art that many variations are possible without departing from the inventive point and effect of the present invention. Therefore, all such variations are also included in the protection scope of the present invention.
Claims
1. A near-infrared wavelength-switchable pulsed fiber laser, characterized in that: Including 793nm cladding pump, 793nm / 2000nm cladding pump combiner, rare earth metal thulium doped fiber, fiber circulator, high nonlinear fiber, fiber polarizer 1, polarization-maintaining photonic crystal fiber, 50:50 fiber coupler, polarization controller 1, polarization controller 2, fiber polarizer 2, polarization controller 3, 90:10 fiber coupler, The 793 nm cladding pump is connected to one end of the 793 nm / 2000 nm cladding pump combiner, the other end of the 793 nm / 2000 nm cladding pump combiner is connected to one end of the rare earth metal thulium doped fiber, the other end of the rare earth metal thulium doped fiber is connected to port 1 of the fiber circulator, port 2 of the fiber circulator is connected to the high nonlinear fiber, the other end of the high nonlinear fiber is connected to the fiber polarizer 1, the other end of the fiber polarizer 1 is connected to the polarization-maintaining photonic crystal fiber, the other end of the polarization-maintaining photonic crystal fiber is connected to the 50:50 fiber coupler, The other end of the 50:50 fiber coupler is respectively connected to the two ends of polarization controller one to form a loop, the 3 ports of the fiber circulator are connected to polarization controller two, the other end of polarization controller two is connected to fiber polarizer two, the other end of fiber polarizer two is connected to polarization controller three, the other end of polarization controller three is connected to a 90:10 fiber coupler, the other end of the 90:10 fiber coupler is connected to a 793 nm / 2000 nm cladding pump combiner to form a loop, and the port of the 90:10 fiber coupler serves as the output port of the entire laser.
2. The near-infrared wavelength-switchable pulsed fiber laser according to claim 1, characterized in that: The 50:50 fiber coupler is a 1×2 coupler with a splitting ratio of 50:
50.
3. The near-infrared wavelength-switchable pulsed fiber laser according to claim 1, characterized in that: The 90:10 fiber coupler is a 1×2 coupler with a splitting ratio of 90:
10. The end of the 90:10 fiber coupler with 10% of the output power is used as the output port of the entire laser.
4. The near-infrared wavelength-switchable pulsed fiber laser according to claim 1, characterized in that: The optical path transmission direction of the fiber optic circulator is clockwise. Light can only be transmitted from port 1 to port 2 of the fiber optic circulator, and then from port 2 to port 3. The transmission direction is irreversible.