Low-noise and high-gain optical fiber amplifier

Abstract

The utility model discloses an optical fiber amplifier with low noise and high gain. Comprising a first 980 pump, a first wavelength division multiplexer, a first erbium-doped optical fiber, a second isolator, a second wavelength division multiplexer, a second erbium-doped optical fiber, a third wavelength division multiplexer, a third isolator, a first filter, a fourth wavelength division multiplexer, an erbium-ytterbium co-doped optical fiber, a fifth wavelength division multiplexer, a fourth isolator and a second filter which are sequentially connected through optical fibers, the first wavelength division multiplexer is further connected with the first isolator, the second wavelength division multiplexer is further connected with the second 980 pump, and the fourth wavelength division multiplexer is further connected with the 940 pump. The amplifier can restrain spontaneous emission ASE generated in the amplification process, noise is remarkably reduced, and therefore the gain efficiency and stability of signals are improved.

Description

Technical Field

[0001] This utility model relates to fiber optic sensing technology, specifically a low-noise, high-gain fiber optic amplifier. Background Technology

[0002] In fiber optic sensing systems, stable and efficient signal transmission typically requires pulse signal fiber amplifiers with low noise and high gain characteristics. However, common fiber amplifiers are limited by gain saturation effects, causing the input pulse signal light to easily reach saturation during the initial amplification stage, resulting in amplified spontaneous emission (ASE) in the gain fiber. This amplified ASE not only reduces the system gain but also increases the noise level, thus adversely affecting the performance of the fiber amplifier. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a low-noise, high-gain fiber optic amplifier. This amplifier can suppress spontaneous emission (ASE) generated during amplification, significantly reduce noise, and thus improve signal gain efficiency and stability.

[0004] The technical solution to achieve the purpose of this utility model is:

[0005] A low-noise, high-gain fiber amplifier includes a first 980 pump, a first wavelength division multiplexer, a first erbium-doped fiber, a second isolator, a second wavelength division multiplexer, a second erbium-doped fiber, a third wavelength division multiplexer, a third isolator, a first filter, a fourth wavelength division multiplexer, an erbium-ytterbium co-doped fiber, a fifth wavelength division multiplexer, a fourth isolator, and a second filter, all connected sequentially by optical fibers. The first wavelength division multiplexer is also connected to the first isolator, the second wavelength division multiplexer is also connected to the second 980 pump, and the fourth wavelength division multiplexer is also connected to the 940 pump.

[0006] In the aforementioned fiber amplifier, the first 980 nm pump provides 980 nm pump light; the first isolator isolates backlight and reduces noise interference; the first wavelength division multiplexer couples the first 980 nm pump light with the pulse signal light isolated by the first isolator into the first erbium-doped fiber; the first erbium-doped fiber amplifies the output light from the first wavelength division multiplexer; the second 980 nm pump provides 980 nm pump light; the second isolator isolates backlight and reduces noise; the second wavelength division multiplexer couples the second 980 nm pump light with the amplified light isolated by the second isolator into the second erbium-doped fiber; the second erbium-doped fiber amplifies the output light from the second wavelength division multiplexer; the third wavelength division multiplexer filters out the 980 nm light from the 980 nm pump and the second 980 nm pump; the third isolator further isolates backlight and reduces noise; the first filter filters out noisy light; and the 940 nm pump provides 940 nm pump light. The 940nm pump light; the fourth wavelength division multiplexer is used to couple the 940nm pump light and the second-stage amplified light filtered by the first filter into the erbium-ytterbium co-doped fiber; the erbium-ytterbium co-doped fiber is used to couple the output light of the fourth wavelength division multiplexer for third-stage amplification; the fifth wavelength division multiplexer is used to filter out the 940nm pump light; the fourth isolator is used to further isolate the reverse light and reduce noise; the second filter is used to filter the noisy light and finally output a low-noise, high-gain pulse signal light.

[0007] The principle of this technical solution is to use pump light of different wavelengths to excite rare earth ions (Er) in erbium-doped fiber or erbium-ytterbium co-doped fiber. 3+ and Yb 3+ The signal light gain is achieved through stimulated emission, and noise light is removed, thereby ensuring the quality of the output signal light.

[0008] First, the input pulsed signal light passes through a first isolator, which effectively isolates the reflected light. Then, a first 980 nm pump provides 980 nm pump light, which is coupled to the signal light through a first wavelength division multiplexer and enters the first erbium-doped fiber. During this process, the Erbium in the erbium-doped fiber... 3+ Ions absorb the pump light energy at 980 nm and transfer the energy to the signal light through stimulated emission, thereby enhancing the intensity of the signal light and completing the first-order gain.

[0009] Subsequently, the signal light passes through a second isolator, which is used to further isolate the backlight and reduce noise interference. Then, the signal light is coupled to the 980 nm pump light provided by the second 980 pump through a second wavelength division multiplexer and enters the second erbium-doped fiber to achieve second-order gain. Then, the signal light passes through a third wavelength division multiplexer to filter out the 980 nm pump light and passes through a third isolator to further isolate the backlight and reduce the impact of noise.

[0010] Next, the signal light enters the first filter to further remove noise and improve signal quality. Then, the signal light is coupled to the 940 nm pump light provided by the 940 nm pump via the fourth wavelength division multiplexer and enters the erbium-ytterbium co-doped fiber. During this process, Yb 3+ Ions absorb the 940 nm pump light energy and transfer it to Er. 3+ Ions, which further enhance the intensity of the signal light through stimulated emission, thus completing the third-level gain;

[0011] Finally, the signal light passes through the fifth wavelength division multiplexer to filter out the residual 940 nm pump light, and through the fourth isolator to further isolate the reverse light. Finally, it passes through the second filter to remove the remaining noise light, thereby outputting a low-noise, high-gain pulse signal light.

[0012] Overall, this technical solution employs a precise combination of multiple wavelength division multiplexers, isolators, and filters to ensure that noise and backlighting are effectively removed during the gain amplification process of the signal light, ultimately achieving high-gain, low-noise signal light output.

[0013] This technical solution adopts a three-stage amplification design, upgrading the traditional single-stage amplification structure to a three-stage amplification structure. Specifically, the design uses erbium-doped fiber as the first and second-stage pre-amplification medium, and erbium-ytterbium co-doped fiber as the third-stage main amplification medium, realizing multi-stage gain amplification. In this technical solution, spontaneous emission (ASE) is effectively dispersed during each amplification stage, thereby avoiding excessive spontaneous emission caused by gain saturation effect in a single-stage amplifier. By adopting this method, the spontaneous emission in each amplifier is significantly reduced, thereby effectively reducing noise and improving the overall gain performance of the system.

[0014] This amplifier can suppress spontaneous emission (ASE) generated during amplification and significantly reduce noise, thereby improving signal gain efficiency and stability. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an embodiment. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this is not intended to limit the present invention.

[0017] Example:

[0018] Reference Figure 1A low-noise, high-gain fiber amplifier includes a first 980 pump 1, a first wavelength division multiplexer 3, a first erbium-doped fiber 4, a second isolator 6, a second wavelength division multiplexer 7, a second erbium-doped fiber 8, a third wavelength division multiplexer 9, a third isolator 10, a first filter 11, a fourth wavelength division multiplexer 13, an erbium-ytterbium co-doped fiber 14, a fifth wavelength division multiplexer 15, a fourth isolator 16, and a second filter 17, all connected in sequence by optical fibers. The first wavelength division multiplexer 3 is also connected to the first isolator 2, the second wavelength division multiplexer 7 is also connected to the second 980 pump 5, and the fourth wavelength division multiplexer 13 is also connected to the 940 pump 12.

[0019] In the aforementioned fiber amplifier, the first 980 pump 1 provides 980 nm pump light; the first isolator 2 isolates backlight and reduces noise interference; the first wavelength division multiplexer 3 couples the light from the first 980 pump 1 with the pulse signal light isolated by the first isolator 2 into the first erbium-doped fiber 4; the first erbium-doped fiber 4 amplifies the output light from the first wavelength division multiplexer 3 in a single stage; the second 980 pump 5 provides 980 nm pump light; the second isolator 6 isolates backlight and reduces noise; the second wavelength division multiplexer 7 couples the light from the second 980 pump 5 with the amplified light isolated by the second isolator 6 into the second erbium-doped fiber 8; the second erbium-doped fiber 8 amplifies the output light from the second wavelength division multiplexer 7 in a second stage; the third wavelength division multiplexer 9 filters out the 980 nm light from the 980 pump 1 and the second 980 pump 5; the third isolator 10 further isolates backlight and reduces noise; the first filter 11 filters out noisy light; and the 940 pump 12 provides 940 nm pump light. The 940nm pump light; the fourth wavelength division multiplexer 13 is used to couple the 940nm light from the 940 pump 12 with the second-stage amplified light filtered by the first filter 11 into the erbium-ytterbium co-doped fiber 14; the erbium-ytterbium co-doped fiber 14 is used to couple the output light from the fourth wavelength division multiplexer 13 for third-stage amplification; the fifth wavelength division multiplexer 15 is used to filter out the 940nm light from the 940 pump 12; the fourth isolator 16 is used to further isolate the reverse light and reduce noise; the second filter 17 is used to filter the noisy light and finally output a low-noise, high-gain pulse signal light.

[0020] This example uses pump light of different wavelengths to excite rare earth ions (Er) in erbium-doped or erbium-ytterbium co-doped fibers. 3+ and Yb 3+ The signal light gain is achieved through stimulated emission, and noise light is removed, thereby ensuring the quality of the output signal light.

[0021] First, the input pulsed signal light passes through the first isolator 2, which effectively isolates the reverse light. Then, the first 980 nm pump 1 provides 980 nm pump light, which is coupled to the signal light through the first wavelength division multiplexer 3 and enters the first erbium-doped fiber 4. During this process, the Erbium in the erbium-doped fiber... 3+ Ions absorb the pump light energy at 980 nm and transfer the energy to the signal light through stimulated emission, thereby enhancing the intensity of the signal light and completing the first-order gain.

[0022] Subsequently, the signal light passes through the second isolator 6, which is used to further isolate the reverse light and reduce noise interference. Then, the signal light is coupled with the 980 nm pump light provided by the second 980 pump 5 through the second wavelength division multiplexer 7, and enters the second erbium-doped fiber 8 to achieve second-order gain. Then, the signal light passes through the third wavelength division multiplexer 9 to filter out the 980 nm pump light, and passes through the third isolator 10 to further isolate the reverse light and reduce the impact of noise.

[0023] Next, the signal light enters the first filter 11 to further remove noise and improve signal quality. Then, the signal light is coupled to the 940 nm pump light provided by the 940 nm pump 12 via the fourth wavelength division multiplexer 13 and enters the erbium-ytterbium co-doped fiber 14. During this process, Yb 3+ Ions absorb the 940 nm pump light energy and transfer it to Er. 3+ Ions, which further enhance the intensity of the signal light through stimulated emission, thus completing the third-level gain;

[0024] Finally, the signal light passes through the fifth wavelength division multiplexer 15 to filter out the residual 940 nm pump light, and through the fourth isolator 16 to further isolate the reverse light. Finally, it passes through the second filter 17 to remove the remaining noise light, thereby outputting a low-noise, high-gain pulse signal light.

[0025] Overall, this example employs a precise combination of multiple wavelength division multiplexers, isolators, and filters to ensure that noise and backlighting are effectively removed during the gain amplification process of the signal light, ultimately achieving high-gain, low-noise signal light output.

Claims

1. A low-noise, high-gain fiber optic amplifier, characterized in that, The system includes a first 980 pump, a first wavelength division multiplexer, a first erbium-doped fiber, a second isolator, a second wavelength division multiplexer, a second erbium-doped fiber, a third wavelength division multiplexer, a third isolator, a first filter, a fourth wavelength division multiplexer, an erbium-ytterbium co-doped fiber, a fifth wavelength division multiplexer, a fourth isolator, and a second filter, all connected sequentially by optical fibers. The first wavelength division multiplexer is also connected to the first isolator, the second wavelength division multiplexer is also connected to the second 980 pump, and the fourth wavelength division multiplexer is also connected to the 940 pump.

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