CN111929964A - Combined amplification method and device of few-mode parameter and strong coupling Raman - Google Patents

Abstract

The invention discloses a combined amplification method of few-mode parameters and strong coupling Raman, which comprises the following steps: carrying out signal modulation on the signal light to obtain four kinds of polarization mode signal light; enabling the four polarization mode signal lights to enter the few-mode optical fiber through a photon lantern mode division multiplexing technology; performing signal modulation on the pump light to obtain four kinds of polarization mode pump light, and coupling the four kinds of light into the long tapered fiber; the pump light after coupling output is coupled into a coupler through phase matching and signal light after being output by the few-mode optical fiber, and then the pump light is input into an amplifier; and (4) uniformly outputting the obtained amplified light through a photon lantern. The invention also discloses a combined amplification device of few-mode parameters and strong coupling Raman. The invention realizes the amplification of high gain and large bandwidth of signal light; the amplified light beam has higher signal-to-noise ratio and better light beam quality, the performance of the optical fiber communication system is effectively improved, and the transmission distance of the optical fiber communication system is increased.

Description

A joint amplification method and device of few mode parameters and strong coupling Raman

technical field

The invention relates to an optical amplification technology in the communication field, in particular to a joint amplification method and device of few-mode parametric and strong coupling Raman.

Background technique

With the rapid development of cloud computing, big data, Internet TV and other services, and the arrival of the 5G era, the demand for the transmission capacity, transmission rate, and transmission distance of optical fiber communication systems is getting higher and higher. In order to meet the needs of optical fiber communication systems, multiplexing technologies such as optical time division multiplexing, wavelength division multiplexing, polarization multiplexing, space division multiplexing, and dense wavelength division multiplexing have been continuously proposed and applied to the expansion of optical communication systems. However, for these technologies for long-distance optical fiber communication systems, the refraction and scattering of light beams, as well as the scattering and absorption of light waves by optical fibers, will attenuate the transmitted signal light, and the performance of optical fiber communication systems will deteriorate. The terminal cannot accurately receive the information of the original signal. In order to ensure the transmission quality of the optical fiber communication system, it is necessary to add an optical amplifier device to amplify the signal during the signal transmission process, so that the signal can be transmitted over a long distance.

At present, the optical amplifiers used at home and abroad mainly include the following three types: erbium-doped fiber amplifiers, fiber Raman amplifiers and fiber parametric amplifiers. Among them, the gain of the erbium-doped fiber amplifier is not flat, the gain bandwidth is relatively narrow, and it can only amplify the light with a wavelength of about 1550nm; the disadvantage of the fiber Raman amplifier is that the gain per unit length is relatively low; Phase matching in amplification is difficult, and the gain spectrum is hump-shaped with a concave center, which makes it impossible to achieve flat gain. Using these three different amplifiers to design an amplification method with a flat gain spectrum has become an urgent problem to be solved at present.

SUMMARY OF THE INVENTION

Purpose of the invention: In view of the above problems, the purpose of the present invention is to provide a joint amplification method of few-mode parameters and strong coupling Raman with balanced gain, and another purpose of the present invention is to provide a combination of few-mode parameters and strong coupling Raman. magnifying device.

Technical solution: The joint amplification method of few-mode parameters and strong coupling Raman according to the present invention includes the following steps:

S1: Perform signal modulation on the signal light to obtain four polarization modes of signal light;

S2: Enter the signal light of the four polarization modes into the few-mode fiber through the photonic lantern mode division multiplexing technology;

S3: The pump light is signal-modulated to obtain four polarization modes of pump light, and the four kinds of light are coupled into the long taper fiber; S4: The pump light coupled out in S3 is phase-matched, and S2 The signal light output by the few-mode fiber is coupled into the coupler to realize the fiber parametric amplification process, and the signal light is amplified with large bandwidth and high gain, and then the output light is input to the amplifier;

S5: The amplified light obtained by S4 is output through the photon lantern to equalize.

The modes of the four polarization modes of the signal light in the step S1 are LP ₀₁ , LP ₁₁ , LP ₂₁ , and LP ₀₂ respectively. Since the signal lights of these four modes are orthogonal modes, the intermodal dispersion in the few-mode fiber is almost zero.

The polarization mode pump light in step S3 has the same mode as the polarization mode signal light in step S1.

In step S4, the amplifier includes a few-mode fiber, a coupler and a pump light source. The signal light enters the coupler after passing through the few-mode fiber, and injects the pump light of the same mode in the reverse direction to realize backward Raman amplification. By adjusting the pump light wavelength, so that the gain spectrum of Raman amplification is opposite to that of parametric amplification, so as to achieve balanced gain for signal light.

A joint amplification device of few-mode parametric and strongly coupled Raman, comprising a signal light source, a first photon lantern, a few-mode fiber, a first pump light source, a phase matcher, a first coupler, an amplifier and a second photon lantern,

The signal light source generates signal light, which is input to the first photon lantern after signal modulation, and the output signal light is input to the few-mode fiber; the pump light source generates pump light, which is input to the elongated cone after signal modulation The optical fiber, the output light is incident on the phase matcher, the pump light after phase matching and the signal light output from the few-mode fiber are incident on the amplifier through the coupler, and the amplified light is obtained, and finally output through the second photon lantern.

The amplifier includes a few-mode fiber, a second coupler, and a second pump light source, and the signal light enters the second coupler after passing through the few-mode fiber, and reversely injects pump light of the same mode.

Beneficial effect: Compared with the prior art, the present invention has the following significant advantages:

1. The present invention utilizes the optical fiber parametric amplification technology and the backward Raman amplification technology to achieve high gain and large bandwidth amplification of the signal light, thereby realizing the balanced gain of the signal light of four different modes;

2. The noise of the pump light source of reverse pumping is averaged during the transmission process, and the amplified beam has a higher signal-to-noise ratio and better beam quality, which effectively improves the performance of the optical fiber communication system and increases the transmission distance of the optical fiber communication system.

Description of drawings

FIG. 1 is a schematic diagram of the structure of the device of the present invention.

Detailed ways

A method for joint amplification of few-mode parameters and strongly coupled Raman described in this embodiment includes the following steps:

S1: Perform signal modulation on the signal light to obtain four polarization mode signal lights, namely LP ₀₁ 2, LP ₁₁ 3, LP ₂₁ 4, and LP ₀₂ 5.

S2: The signal light of the four polarization modes enters the few-mode fiber 10 through the photonic lantern mode division multiplexing technology.

S3: Perform signal modulation on the pump light to obtain pump light with four polarization modes, namely LP ₀₁ 2, LP ₁₁ 3, LP ₂₁ 4, and LP ₀₂ 5. These four kinds of light are coupled into the long drawn tapered fiber 6 .

S4: The pump light coupled and output in S3 is phase matched, and the signal light output by the few-mode fiber 10 of S2 is coupled into the coupler to realize fiber parametric amplification. The signal light is amplified with large bandwidth and high gain, and then the output is output. light input to the amplifier. The amplifier includes a few-mode fiber, a coupler, and a pump light source. The signal light enters the coupler after passing through the few-mode fiber, and reversely injects the pump light of the same mode to achieve backward Raman amplification. By adjusting the wavelength of the pump light, the pull The gain spectrum of Mann amplification is opposite to the gain spectrum of parametric amplification, so as to achieve equalized gain for signal light.

S5: The amplified light obtained by S4 is output through the photon lantern to equalize.

As shown in FIG. 1 , a joint amplification device of few-mode parametric and strongly coupled Raman described in this example includes a signal light source 8 , a first photon lantern 9 , a first few-mode optical fiber 10 , and a first pump light source 1 , a phase matcher 7, a first coupler 11, an amplifier and a second photon lantern 13, the signal light source 8 generates signal light, after signal modulation, it is input to the first photon lantern 9, and the output signal light is input to the first few mode Optical fiber 10; the first pump light source 1 generates pump light, after signal modulation, it is input to the long taper fiber 6, and the output light is incident on the phase matcher 7, and the pump light after phase matching is the same as the first few mode The signal light output from the optical fiber 10 is incident on the amplifier through the first coupler 11 to obtain amplified light, which is finally output through the second photon lantern 13 . The amplifier includes a few-mode fiber, a second coupler 12 and a second pump light source 14, and the signal light enters the second coupler 12 after passing through the few-mode fiber, and injects pump light of the same mode in the opposite direction.

Claims (6)

1. A combined amplification method of few-mode parameters and strong-coupling Raman is characterized by comprising the following steps:

s1: carrying out signal modulation on the signal light to obtain four kinds of polarization mode signal light;

s2: enabling the four polarization mode signal lights to enter the few-mode optical fiber through a photon lantern mode division multiplexing technology;

s3: performing signal modulation on the pump light to obtain four kinds of polarization mode pump light, and coupling the four kinds of light into a long tapered fiber (6);

s4: the pump light after being coupled and output in the S3 is coupled into a coupler through phase matching with the signal light after being output by the S2 few-mode optical fiber, and then the output light is input into an amplifier;

s5: the amplified light obtained at S4 is equalized and output through a photonic lantern.

2. The method of claim 1, wherein the modes of the four polarization mode signal lights of step S1 are LP₀₁（2）、LP₁₁（3）、LP₂₁（4）、LP₀₂（5）。

3. The method of claim 1, wherein the step S3 polarization mode pump light and the step S1 polarization mode signal light have the same mode.

4. The method of claim 1, wherein the step S4 amplifier comprises a few-mode fiber, a coupler and a pump light source, and the signal light enters the coupler after passing through the few-mode fiber, and the pump light of the same mode is injected in reverse.

5. A combined amplification device of few-mode parameters and strong-coupling Raman is characterized by comprising a signal light source (8), a first photon lantern (9), few-mode optical fibers, a first pump light source (1), a phase matcher (7), a first coupler (11), an amplifier and a second photon lantern (13), wherein the signal light source (8) generates signal light, the signal light is input into the first photon lantern (9) after being modulated by signals, and the output signal light is input into the few-mode optical fibers; the first pump light source (1) generates pump light, the pump light is input to the long tapered fiber (6) after signal modulation, output light is incident to the phase matcher (7), the pump light after phase matching and signal light output from the few-mode fiber are incident to the amplifier through the coupler to obtain amplified light, and finally the amplified light is output through the second photon lantern (13).

6. The device of claim 5, wherein the amplifier comprises a few-mode fiber, a second coupler (12) and a second pump light source (14), and the signal light enters the second coupler (12) after passing through the few-mode fiber, and the pump light of the same mode is injected in a reverse direction.

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