An erbium-ytterbium co-doped fiber laser capable of matched filtering
By employing tunable filters and fibers with different doping structures in erbium-ytterbium co-doped fiber lasers, efficient amplification of signal light and improvement of signal-to-noise ratio were achieved, solving the problems of high manufacturing difficulty and waste of raw materials, and improving the stability and signal quality of the system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI B&A TECH CO LTD
- Filing Date
- 2025-06-26
- Publication Date
- 2026-07-14
AI Technical Summary
Existing erbium-ytterbium co-doped fiber lasers face challenges in manufacturing and material waste in high-precision, long-distance applications. In particular, the adaptation of multiple filters with different center wavelengths increases production complexity and cost.
By employing a tunable filter matched to the output wavelength of the seed light source, and combining erbium-ytterbium co-doped optical fibers with low-doped fine cores and high-doped coarse cores, multi-stage amplification and filtering processes are used to reduce the need for multiple filters with different center wavelengths, thereby achieving efficient amplification of the signal light and improved signal-to-noise ratio.
It simplifies the production process, reduces manufacturing costs, improves the beam quality and signal-to-noise ratio of the signal light, reduces nonlinear effects, and enhances the stability and reliability of the system.
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Figure CN224502631U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of fiber lasers, and in particular to a matched-filterable erbium-ytterbium co-doped fiber laser. Background Technology
[0002] With the increasing maturity of erbium-ytterbium co-doped fiber manufacturing processes and semiconductor laser technology, erbium-ytterbium co-doped fiber lasers based on erbium-ytterbium co-doped fibers are gaining increasing attention. The 1550nm band MOPA erbium-ytterbium co-doped fiber laser, with its advantages of high beam quality, tunable wavelength, pulse width, and repetition rate, and high integration, plays a crucial role in high-precision, long-distance applications such as automotive and airborne lidar. These high-precision applications place demands on erbium-ytterbium co-doped fiber lasers, requiring high peak power, high signal-to-noise ratio, and low nonlinear effects, driving the continuous development and innovation of erbium-ytterbium co-doped fiber laser technology. High-quality erbium-ytterbium co-doped fiber lasers are also in high demand in numerous fields such as industrial processing and communications, providing strong support for the development of various industries.
[0003] Previously, to meet the requirements of erbium-ytterbium co-doped fiber lasers in high-precision, long-distance applications, especially in addressing issues such as improving the signal-to-noise ratio, a common solution was to add narrowband filters to the optical path. Since DFB chips have a certain wavelength distribution range, multiple filters with different center wavelengths are needed for adaptation. This approach is quite common in the industry, and many companies and research institutions use this method to try to solve similar problems in hopes of achieving certain performance indicators.
[0004] However, the existing method of using multiple filters with different center wavelengths for adaptation has significant drawbacks. This method greatly increases the waste of raw materials because it requires preparing multiple filters of different specifications. At the same time, it also significantly increases the manufacturing difficulty, making the production process more complex and cumbersome, and making it difficult to efficiently produce erbium-ytterbium co-doped fiber lasers that meet the requirements. Utility Model Content
[0005] In order to obtain high-quality signal output while reducing manufacturing difficulty, this application provides a matched-filterable erbium-ytterbium co-doped fiber laser.
[0006] The matched-filterable erbium-ytterbium co-doped fiber laser provided in this application adopts the following technical solution:
[0007] A matched-filterable erbium-ytterbium co-doped fiber laser includes a seed source, a tunable filter, a pump laser, and a pump beam splitter. The output of the seed source is connected to a subsequent optical path via a first beam combiner, a first erbium-ytterbium co-doped fiber, a tunable filter, a second erbium-ytterbium co-doped fiber, and a second beam combiner. The output pump light of the pump laser enters the input of the first and second beam combiners respectively through the pump beam splitter.
[0008] By adopting the above technical solution, the pulsed laser emitted by the seed light source is combined with the pump light by the first beam combiner and enters the first erbium-ytterbium co-doped fiber for forward amplification. The tunable filter filters the signal light, and the center wavelength is electrically adjustable to match the input wavelength of the seed light source, eliminating the need for multiple filters with different center wavelengths, reducing raw material waste and manufacturing difficulty. After being back-amplified by the second erbium-ytterbium fiber, the final signal is output through the second beam combiner. The pump light emitted by the pump laser is split into two paths by the pump light beam splitter, which are amplified and powered in two stages respectively, realizing effective amplification of the signal light, improving the peak power and signal-to-noise ratio of the fiber laser, and reducing nonlinear effects.
[0009] Preferably, the center wavelength of the tunable filter can be electrically adjusted to match the input wavelength of the SEED.
[0010] By adopting the above technical solution, the seed wavelength is matched in real time through electrical tuning to realize the dynamic wavelength selection function, which improves the system's adaptability to different wavelength signals, while effectively suppressing noise and nonlinear effects and improving the spectral purity of the output laser.
[0011] Preferably, the output signal light of the seed light source enters the first beam combiner through the first isolator.
[0012] By adopting the above technical solution, interference and damage to the seed light source by the reverse transmission light can be effectively prevented, ensuring the stable operation of the seed light source and improving the system reliability.
[0013] Preferably, the output signal light of the first erbium-ytterbium co-doped fiber enters the tunable filter through the second isolator.
[0014] By adopting the above technical solution, forward and backward transmission light are isolated, mutual interference between optical paths is reduced, system stability is improved, and front-end optical path components are protected.
[0015] Preferably, the output optical signal of the second beam combiner enters the subsequent optical path through the third isolator.
[0016] By adopting the above technical solution, external reflected light is prevented from entering the system, protecting the entire laser system, while ensuring the quality and stability of the output laser.
[0017] Preferably, the first erbium-ytterbium co-doped fiber is a low-doped, fine-core erbium-ytterbium co-doped double-clad active fiber.
[0018] By adopting the above technical solution, the first-stage amplification uses a low-doped fine-core structure to optimize the pump light absorption efficiency, maintain good beam quality in the initial amplification stage, and provide a high-quality input optical signal for subsequent high-power amplification.
[0019] Preferably, the second erbium-ytterbium co-doped fiber is a highly doped coarse-core erbium-ytterbium co-doped double-clad active fiber.
[0020] By adopting the above technical solution and using a highly doped coarse-core structure design, the pump energy conversion efficiency is significantly improved, and higher power output is achieved in the second-stage amplification. At the same time, the coarse-core structure can reduce the risk of nonlinear damage and improve the system reliability.
[0021] Preferably, the seed light source is a DFB laser.
[0022] By adopting the above technical solution and using a DFB laser as a seed source, a narrow linewidth and highly stable single longitudinal mode seed light is provided, ensuring that the output laser has good spectral purity and phase consistency, making it suitable for high-precision application scenarios.
[0023] In summary, this application includes at least one of the following beneficial technical effects:
[0024] 1. A tunable filter is used for filtering, which can adjust the center wavelength and bandwidth of the filter according to the wavelength matching of the seed signal, avoiding the traditional design scheme of using multiple discrete components for matching, and can obtain high signal-to-noise ratio and high beam quality;
[0025] 2. By avoiding the use of multiple filters with different center wavelengths, production efficiency was improved and manufacturing costs were reduced. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the main optical path in an embodiment of this application.
[0027] Reference numerals in the figures: 1. Seed light source; 2. Pump laser; 3. Pump beam splitter; 4. First isolator; 5. First beam combiner; 6. First erbium-ytterbium co-doped fiber; 7. Second isolator; 8. Tunable filter; 9. Second erbium-ytterbium co-doped fiber; 10. Second beam combiner; 11. Third isolator. Detailed Implementation
[0028] The following combination Figure 1 This application will be described in further detail.
[0029] This application discloses a matched-filterable erbium-ytterbium co-doped fiber laser.
[0030] Reference Figure 1 A matched-filter erbium-ytterbium co-doped fiber laser includes a seed light source 1, a first isolator 4, a first combiner 5, a first erbium-ytterbium co-doped fiber 6, a second isolator 7, a tunable filter 8, a second erbium-ytterbium co-doped fiber 9, a second combiner 10, and a third isolator 11. The pulsed laser emitted from the seed light source 1 passes through the first isolator 4 and the first combiner 5 before entering the first erbium-ytterbium co-doped fiber 6 for primary amplification. The amplified pulsed laser then passes sequentially through the second isolator 7 and the tunable filter 8 before entering the second erbium-ytterbium co-doped fiber 9 for secondary amplification. The amplified pulsed laser then passes sequentially through the second combiner 10 and the third isolator 11 before being output. The center wavelength of the tunable filter 8 is electrically adjustable to match the input wavelength of the seed light, enabling effective processing of the signal light during the primary and secondary amplification processes. This improves the peak power and signal-to-noise ratio of the fiber laser and reduces nonlinear effects.
[0031] The fiber laser also includes a pump laser 2 and a pump beam splitter 3. The pump laser emitted by the pump laser 2 is split into two paths by the pump beam splitter 3. One path passes through the first combiner 5 and enters the first erbium-ytterbium co-doped fiber 6 to power the first erbium-ytterbium co-doped fiber 6; the other path passes through the second combiner 10 and enters the Diehr erbium-ytterbium co-doped fiber 9 to power the second erbium-ytterbium co-doped fiber 9.
[0032] Specifically, seed light source 1 serves as the source of the laser signal light, used to generate stable narrow-linewidth pulsed laser light. In this embodiment, a DFB laser is used, which has advantages such as single-mode output and narrow linewidth, providing a stable pulsed laser signal. In practical applications, other types of lasers, such as DBR lasers, can also be used as seed light source 1, which can also generate high-quality laser signals.
[0033] The function of the first isolator 4 is to prevent backlight from entering the seed light source 1, thus avoiding interference or even damage to the seed light source 1. In this embodiment, an ISO1 type isolator is used, which is a Faraday rotation magneto-optical isolator. It utilizes the magneto-optical effect to rotate the polarization plane of light, thereby allowing light to pass through in only one direction. Besides the ISO1 type, other Faraday rotation magneto-optical isolators with similar functions can also be selected. The first isolator 4 is connected to the seed light source 1 via optical fiber to ensure that the signal light can be successfully transmitted to the next component. The input end of the first isolator 4 is connected to the output end of the seed light source 1 via optical fiber to ensure that the signal light can be successfully transmitted to the next component.
[0034] The first combiner 5 is connected to the first isolator 4, the first optical fiber, and the pump beam splitter 3 via optical fibers, enabling the pump light and signal light to be accurately converged and enter the first erbium-ytterbium co-doped fiber 6 for amplification. In this embodiment, the first combiner 5 is a tapered double-clad fiber combiner, which can improve the coupling efficiency between the pump light and the signal light.
[0035] The first erbium-ytterbium co-doped fiber 6 is a low-doped, fine-core, double-clad active fiber. The erbium and ytterbium ions inside this fiber can absorb the energy of the pump light, thereby amplifying the signal light. The low-doped, fine-core structure is beneficial for improving the amplification efficiency and beam quality of the signal light. One end of the first erbium-ytterbium co-doped fiber 6 is connected to the input end of the first combiner 5 via a pipeline, and the other end is connected to the input end of the second isolator 7 via an optical fiber, realizing continuous transmission and amplification of the signal light.
[0036] The second isolator 7 has a similar structure to the first isolator 4, and its function is to isolate backward-returning light, such as spontaneous emission light from the subsequent stage and backward pulses. By isolating the backward-returning light, the influence of backward light on the preceding optical path can be reduced, improving the stability of the entire optical path system. The output of the second isolator 7 is connected to the tunable filter 8 via optical fiber to ensure that the signal light is not interfered with by backward light during transmission.
[0037] The tunable filter 8 is used to filter the pulsed laser light after the first stage of amplification. In this embodiment, the tunable filter 8 is a center-wavelength electrically tunable bandpass optical filter with a wavelength range of 1528-1567 nm, a 3dB bandwidth of 1 nm, a sideband suppression of >30 dB, and a tuning resolution of 0.1 nm. The tunable filter 8 filters the pulsed laser light, removing unwanted wavelength components and improving the purity and signal-to-noise ratio of the signal light. The center wavelength of the tunable filter 8 can be electrically tunable to match the SEED input wavelength, avoiding the problem of needing multiple filters with different center wavelengths for adaptation in traditional methods. The tunable filter 8 may include a piezoelectric ceramic-driven tuning mechanism or a thermoelectric cooler temperature tuning mechanism to achieve precise adjustment of the center wavelength. The output end of the tunable filter 8 is connected to one end of a second erbium-ytterbium co-doped double-clad active fiber via an optical fiber to filter the signal light after the first stage of amplification.
[0038] The second erbium-ytterbium co-doped fiber 9 is a highly doped, coarse-core, double-clad active fiber. Its highly doped, coarse-core structure allows it to absorb more pump light energy, achieving more efficient signal amplification. The end of the second erbium-ytterbium co-doped double-clad active fiber furthest from the tunable filter 8 is connected via an optical fiber to the input end of the second combiner 10.
[0039] The second combiner 10 has a similar structure to the first combiner 5, also employing a tapered double-clad fiber combiner to combine the pump light with the filtered pulsed laser, effectively merging the pump light and the second-stage amplified pulsed laser. The output of the second combiner 10 is connected to the input of the third isolator 11 via optical fiber.
[0040] The third isolator 11 has a similar structure to the second isolator 7 and is used to isolate the backlight and protect the entire fiber laser. The output end of the third isolator 11 is set as the output end of the fiber laser.
[0041] The multimode pump laser 2 is a 940nm / 916nm multimode pump laser 2, such as an AlGaAs semiconductor laser array, with an emission wavelength of 940nm±5nm or 916nm±5nm, providing energy for the entire amplification process.
[0042] The pump beam splitter 3 forms the first and second branch channels through a fused taper process, and a stress buffer ring is provided at the fused taper section. The stress buffer ring has three arc-shaped grooves spaced at intervals along the circumference, which can reduce the impact of stress on the splitter and improve its stability and reliability. The pump beam splitter 3 is connected to the pump laser 2, the first beam combiner 5, and the second beam combiner 10 via optical fibers.
[0043] The implementation principle of a matched-filterable erbium-ytterbium co-doped fiber laser according to an embodiment of this application is as follows: A pulsed laser emitted from a seed light source 1 sequentially passes through a first isolator 4 and a first beam combiner 5 before entering a first erbium-ytterbium co-doped fiber 6, where it encounters the pump light and achieves first-stage amplification. The first-stage amplified pulsed laser is then filtered by a second isolator 7 and a tunable filter 8 before entering a second beam combiner 10 through a second erbium-ytterbium co-doped fiber 9, where it encounters the pump light and achieves second-stage amplification. The second-stage amplified pulsed laser is then output through a third isolator 11. This multi-stage amplification and filtering improves peak power and signal-to-noise ratio, reduces nonlinear effects, simplifies the filter structure, and reduces raw material waste and manufacturing difficulty.
[0044] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A matched-filterable erbium-ytterbium co-doped fiber laser, characterized in that: The system includes a seed light source (1), a tunable filter (8), a pump laser (2), and a pump beam splitter (3). The output of the seed light source (1) is connected to the subsequent optical path in sequence through a first beam combiner (5), a first erbium-ytterbium co-doped fiber (6), a tunable filter (8), a second erbium-ytterbium co-doped fiber (9), and a second beam combiner (10). The output pump light of the pump laser (2) enters the input of the first beam combiner (5) and the second beam combiner (10) through the pump beam splitter (3).
2. The matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1, characterized in that: The center wavelength of the tunable filter (8) can be electrically adjusted to match the input wavelength of the SEED.
3. The matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1, characterized in that: The output signal light of the seed light source (1) enters the first bundler (5) through the first isolator (4).
4. A matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1 or 3, characterized in that: The output signal light of the first erbium-ytterbium co-doped fiber (6) enters the tunable filter (8) through the second isolator (7).
5. A matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1 or 3, characterized in that: The output optical signal of the second beam combiner (10) enters the subsequent optical path through the third isolator (11).
6. A matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1, characterized in that: The first erbium-ytterbium co-doped fiber (6) is a low-doped, fine-core erbium-ytterbium co-doped double-clad active fiber.
7. A matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1, characterized in that: The second erbium-ytterbium co-doped fiber (9) is a highly doped coarse-core erbium-ytterbium co-doped double-clad active fiber.
8. A matched-filterable erbium-ytterbium co-doped fiber laser according to claim 1, characterized in that: The seed light source (1) is set as a DFB laser.