An adaptive raman gain compensation system and method

Abstract

The application discloses a self-adaptive Raman gain compensation system and method, and relates to the technical field of optical communication, wherein the self-adaptive Raman gain compensation system comprises: an optical fiber link; a Raman optical amplifier used for amplifying an input optical signal transmitted by the optical fiber link; a centralized optical amplifier used for amplifying an optical signal output by the Raman optical amplifier; and a compensation device used for acquiring and comparing partial optical powers of the input optical signal and the optical signal output by the centralized optical amplifier, and controlling the gain of the centralized optical amplifier based on a comparison result. The application can realize self-adaptive gain compensation when the gain of the Raman amplifier is insufficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical access network, and in particular to a self-adaptive Raman gain compensation system and method. BACKGROUND

[0002] With the gradual entry of 400G coherent technology into the commercial stage, the disadvantages of traditional G.652D optical fiber in optical fiber loss and nonlinear effects are also more and more obvious. The deployment focus of future optical fiber cables needs to be shifted, and the industry is gradually shifting the deployment focus to G.654E optical fiber.

[0003] G.652D optical fiber is the most conventional single-mode optical fiber, with the shortest cutoff wavelength, which can be used for both 1550nm and 1310nm. In the past, except for FTTH (fiber to the home) home cables, long-distance and metropolitan optical fibers were almost all G.652D optical fibers. G.654E optical fiber has the lowest 1550nm attenuation coefficient (about 15% lower than G652D), so it is called low-loss optical fiber, and the dispersion coefficient is basically the same as G.652D. In the past, it was mainly used in submarine cable communication systems. To meet the needs of long-distance and large-capacity submarine cable communication, G.654E optical fiber has made two improvements:

[0004] (1) Reduce the loss of the optical fiber; from 0.2dB / km of G.652D to 0.17dB / km (standard value).

[0005] (2) Increase the mode field diameter of the optical fiber; the larger the mode field diameter of the optical fiber, the smaller the energy density through the cross section of the optical fiber, thereby improving the nonlinear effects of the optical fiber and improving the signal-to-noise ratio of the optical fiber communication system.

[0006] From a technical point of view: compared with G.652D optical fiber, G.654.E optical fiber has obvious advantages in electric relay distance, which can extend the electric relay transmission distance and reduce the relay station setting.

[0007] However, in the scenario of using a Raman optical amplifier as an optical relay, since the effective area of the G.654E optical fiber is significantly larger than that of the G.652D optical fiber, the stimulated Raman scattering effect in the G.654E optical fiber medium is much lower than that in the G.652D optical fiber. As a result, when the same length of G.654E optical fiber is used to replace the original G.652D optical fiber link, the Raman amplifier that can completely compensate for the loss of the optical fiber link will have a serious gain deficiency. Generally, the gain can be improved by increasing the Raman pump light power, but the introduction of a super-high power pump light source will greatly increase the system cost and power consumption, and the technical feasibility is low. SUMMARY

[0008] In view of the defects in the prior art, the first aspect of the present application provides a self-adaptive Raman gain compensation system, which can realize self-adaptive gain compensation when the gain of a Raman amplifier is insufficient.

[0009] To achieve the above object, the technical solution adopted by the present application is:

[0010] A self-adaptive Raman gain compensation system comprises:

[0011] An optical fiber link;

[0012] A Raman optical amplifier for amplifying an input optical signal transmitted by the optical fiber link;

[0013] A centralized optical amplifier for amplifying an optical signal output by the Raman optical amplifier;

[0014] A compensation device for acquiring and comparing partial optical powers of the input optical signal and the optical signal output by the centralized optical amplifier, and controlling the gain of the centralized optical amplifier based on the comparison result.

[0015] In some embodiments, the compensation device comprises a control circuit, an optical power feedforward unit and an optical power feedback unit;

[0016] The optical power feedforward unit is configured to split the input optical signal input into the optical fiber link and acquire a corresponding first optical power value;

[0017] The optical power feedback unit is configured to split the optical signal output by the Raman optical amplifier and acquire a corresponding second optical power value;

[0018] The control circuit is configured to receive and compare the first optical power value and the second optical power value, and control the gain of the centralized optical amplifier based on the comparison result.

[0019] In some embodiments, the optical power feedforward unit comprises:

[0020] A first optical beam splitter for proportionally distributing the optical power of the input optical signal into two paths for output;

[0021] A first photodetector for receiving one path of optical signal distributed by the first optical beam splitter to acquire the first optical power value.

[0022] In some embodiments, the optical power feedback unit comprises:

[0023] A second optical beam splitter for proportionally distributing the optical power of the optical signal output by the centralized optical amplifier into two paths for output;

[0024] A second photodetector is configured to receive a light signal split by the second optical splitter to obtain a second optical power value.

[0025] In some embodiments, the first optical splitter and the second optical splitter are configured to split the light signal in a ratio of 95:5.

[0026] In some embodiments, when the ratio of the first optical power value and the second optical power value is less than a set value, the control circuit controls the centralized optical amplifier to decrease the gain until the ratio of the first optical power value and the second optical power value is equal to the set value.

[0027] When the ratio of the first optical power value and the second optical power value is greater than the set value, the control circuit controls the centralized optical amplifier to increase the gain until the ratio of the first optical power value and the second optical power value is equal to the set value.

[0028] In some embodiments, the set value is 1.

[0029] In some embodiments, the centralized optical amplifier is a semiconductor optical amplifier or an erbium-doped fiber amplifier.

[0030] In some embodiments, the optical fiber link is a G.654E optical fiber link.

[0031] The second aspect of the present application provides an adaptive Raman gain compensation method, which can realize adaptive gain compensation when the gain of the Raman amplifier is insufficient.

[0032] To achieve the above object, the technical solution adopted by the present application is as follows:

[0033] A compensation method of the adaptive Raman gain compensation system described above, the method comprising the following steps:

[0034] Obtaining the partial optical power of the input optical signal and the optical signal output by the centralized optical amplifier;

[0035] Adjusting the gain of the centralized optical amplifier by the compensation device, so that the ratio of the partial optical power of the input optical signal and the optical signal output by the centralized optical amplifier is a set value.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] The adaptive Raman gain compensation system of this invention includes an optical fiber link, a Raman optical amplifier, a centralized optical amplifier, and a compensation device. The optical fiber link is mainly used to transmit the input optical signal; the Raman optical amplifier amplifies the input optical signal transmitted through the optical fiber link; the centralized optical amplifier amplifies the optical signal output by the Raman optical amplifier; and the compensation device acquires and compares a portion of the optical power of the input optical signal and the optical power of the optical signal output by the centralized optical amplifier, and controls the gain of the centralized optical amplifier based on the comparison result. The adaptive Raman gain compensation system of this invention acquires a portion of the optical power of the input optical signal and the optical power of the optical signal output by the centralized optical amplifier; and adjusts the gain of the centralized optical amplifier through the compensation device so that the ratio of the partial optical power of the input optical signal to the optical power of the optical signal output by the centralized optical amplifier is a set value. This enables adaptive gain compensation when the gain of the Raman amplifier is insufficient. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the adaptive Raman gain compensation system in an embodiment of the present invention;

[0039] Figure 2 This is a flowchart of the adaptive Raman gain compensation method in an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] See Figure 1 As shown in the figure, an embodiment of the present invention discloses an adaptive Raman gain compensation system, which includes an optical fiber link, a Raman optical amplifier, a centralized optical amplifier, and a compensation device.

[0042] The optical fiber link is mainly used to transmit the input optical signal. In this embodiment, a G.654E optical fiber link can be selected. The Raman optical amplifier is used to amplify the input optical signal transmitted by the optical fiber link. The centralized optical amplifier is used to amplify the optical signal output by the Raman optical amplifier. The compensation device is used to acquire and compare part of the optical power of the input optical signal and the optical signal output by the centralized optical amplifier, and control the gain of the centralized optical amplifier based on the comparison result.

[0043] In a specific implementation, the compensation device includes a control circuit, an optical power feedforward unit, and an optical power feedback unit.

[0044] The optical power feedforward unit is used to split the input optical signal input to the optical fiber link and obtain the corresponding first optical power value; the optical power feedback unit is used to split the optical signal output by the Raman optical amplifier and obtain the corresponding second optical power value; the control circuit is used to receive and compare the magnitudes of the first optical power value and the second optical power value, and control the gain of the centralized optical amplifier based on the comparison result.

[0045] In this embodiment, in order to achieve beam splitting and obtain the corresponding first optical power value, the optical power feedforward unit includes a first optical beam splitter and a first photodetector.

[0046] The first optical beam splitter is used to proportionally distribute the optical power of the input optical signal into two output paths; the first photodetector is used to receive one optical signal distributed by the first optical beam splitter to obtain the first optical power value.

[0047] Simultaneously, in order to achieve beam splitting and obtain the corresponding second optical power value, the optical power feedback unit includes a second beam splitter and a second photodetector.

[0048] The second optical beam splitter is used to proportionally distribute the optical power of the output optical signal of the centralized optical amplifier into two outputs; the second photodetector is used to receive one optical signal distributed by the second optical beam splitter to obtain the second optical power value.

[0049] It is worth noting that both the first and second optical beamsplitters are allocated in a 95:5 ratio. That is, after passing through the first beamsplitter, 95% of the optical power is input to the fiber optic link, and the remaining 5% is input to the first photodetector, resulting in an optical power value P1, which is then input to the control circuit. The other path, accounting for 95% of the input optical signal power, passes through the fiber optic link and a Raman amplifier before inputting to a gain-adjustable centralized optical amplifier. The gain control port of this centralized optical amplifier is controlled by the control circuit. The optical signal output from this centralized optical amplifier then passes through a second optical beamsplitter, where 95% of the optical power serves as the system's output optical signal, and the remaining 5% is input to the second photodetector, resulting in an optical power value P2, which is also input to the control circuit. It is understood that other allocation ratios, such as 99:1, can be set as needed; this embodiment of the invention does not impose such limitations.

[0050] Subsequently, the control circuit will make a judgment. When the ratio of the first optical power value and the second optical power value is less than the set value, the control circuit will control the centralized optical amplifier to reduce the gain until the ratio of the first optical power value and the second optical power value is equal to the set value.

[0051] When the ratio of the first optical power value to the second optical power value is greater than a set value, the control circuit controls the centralized optical amplifier to increase its gain until the ratio of the first optical power value to the second optical power value equals the set value. Preferably, this set value can be 1, or it can be set to another value as needed; this embodiment of the invention does not impose any limitations on this.

[0052] The following is a specific example to illustrate this:

[0053] The input optical signal first enters a 95:5 first optical beamsplitter, with 95% of the optical power input to an 80km G.654E fiber optic link and the remaining 5% input to a first photodetector, resulting in an optical power value P1, which is then input to the control circuit. The remaining 95% of the input optical signal power passes through a G.654E fiber optic link and a Raman amplifier before entering a gain-adjustable semiconductor optical amplifier. The gain control port of this semiconductor optical amplifier is controlled by the control circuit. The optical signal output from this semiconductor optical amplifier then passes through a 95:5 second optical beamsplitter, with 95% of the optical power serving as the system's output optical signal and the remaining 5% input to another photodetector, resulting in another optical power value P2, which is also input to the control circuit.

[0054] The embedded software program in the control circuit compares the ratio of the optical power P1 to P2 detected by the two photodetectors to adjust the gain control port of the centralized optical amplifier, thereby changing the gain of the centralized optical amplifier. Specifically, the system is set to P1 / P2 = 1. When the control circuit receives a power ratio P1 / P2 < 1, it controls the semiconductor optical amplifier to decrease its gain until P1 / P2 = 1; conversely, when the control circuit receives a power ratio P1 / P2 > 1, it controls the semiconductor optical amplifier to increase its gain until P1 / P2 = 1. This achieves adaptive gain adjustment for the entire system.

[0055] It is worth noting that the gain-tunable semiconductor optical amplifier in this invention is just one example. All gain-tunable centralized fiber amplifiers are applicable to this system architecture, such as erbium-doped fiber amplifiers, and are also within the scope of protection of this invention.

[0056] The compensation architecture for insufficient Raman amplification gain in G.654E fiber links in this invention can achieve adaptive compensation for insufficient Raman amplification gain by using a low-gain centralized optical amplifier, simple control circuits, and optical devices without changing the pump power of the original Raman optical amplifier. This makes G.654E fiber a stronger replacement for traditional G.652D fiber, more versatile in application scenarios, and conducive to the further promotion of G.654E fiber.

[0057] In summary, the adaptive Raman gain compensation system of this invention includes an optical fiber link, a Raman optical amplifier, a centralized optical amplifier, and a compensation device. The optical fiber link is mainly used to transmit the input optical signal; the Raman optical amplifier amplifies the input optical signal transmitted through the optical fiber link; the centralized optical amplifier amplifies the optical signal output by the Raman optical amplifier; and the compensation device acquires and compares a portion of the optical power of the input optical signal and the optical power of the optical signal output by the centralized optical amplifier, and controls the gain of the centralized optical amplifier based on the comparison result. The adaptive Raman gain compensation system of this invention acquires a portion of the optical power of the input optical signal and the optical power of the optical signal output by the centralized optical amplifier; and adjusts the gain of the centralized optical amplifier through the compensation device, so that the ratio of the partial optical power of the input optical signal to the optical power of the optical signal output by the centralized optical amplifier is a set value. This enables adaptive gain compensation when the gain of the Raman amplifier is insufficient.

[0058] See Figure 2 As shown in the figure, an embodiment of the present invention discloses a compensation method using the above-described adaptive Raman gain compensation system, the method comprising the following steps:

[0059] S1. Obtain a portion of the optical power of the input optical signal and the optical signal output by the centralized optical amplifier.

[0060] S2. The gain of the centralized optical amplifier is adjusted by the compensation device so that the ratio of the partial optical power of the input optical signal to the optical power of the output optical signal of the centralized optical amplifier is a set value.

[0061] In the specific implementation, the input optical signal first enters a 95:5 first optical beamsplitter, where 95% of the optical power is input into an 80km G.654E fiber optic link, and the remaining 5% is input into a first photodetector to obtain an optical power value P1, which is then input into the control circuit. The other 95% of the input optical signal power passes through a G.654E fiber optic link and a Raman amplifier before entering a gain-adjustable semiconductor optical amplifier. The gain control port of this semiconductor optical amplifier is controlled by the control circuit. The optical signal output from this semiconductor optical amplifier then passes through a 95:5 second optical beamsplitter, where 95% of the optical power serves as the system's output optical signal, and the remaining 5% is input into another photodetector to obtain another optical power value P2, which is also input into the control circuit.

[0062] The embedded software program in the control circuit compares the ratio of the optical power P1 to P2 detected by the two photodetectors to adjust the gain control port of the centralized optical amplifier, thereby changing the gain of the centralized optical amplifier. Specifically, the system is set to P1 / P2 = 1. When the control circuit receives a power ratio P1 / P2 < 1, it controls the semiconductor optical amplifier to decrease its gain until P1 / P2 = 1; conversely, when the control circuit receives a power ratio P1 / P2 > 1, it controls the semiconductor optical amplifier to increase its gain until P1 / P2 = 1. This achieves adaptive gain adjustment for the entire system.

[0063] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An adaptive Raman gain compensation system, characterized by, The method comprises the following steps: an optical fiber link; a Raman optical amplifier for amplifying an input optical signal transmitted by the optical fiber link; a centralized optical amplifier for amplifying an optical signal output by the Raman optical amplifier; a compensation device for acquiring and comparing partial optical powers of the input optical signal and the optical signal output by the centralized optical amplifier, and controlling a gain of the centralized optical amplifier based on a comparison result; the optical fiber link is a G.654E optical fiber link; the compensation device comprises a control circuit, an optical power feedforward unit, and an optical power feedback unit; the optical power feedforward unit is configured to split the input optical signal input into the optical fiber link and acquire a corresponding first optical power value; the optical power feedback unit is configured to split the optical signal output by the Raman optical amplifier and acquire a corresponding second optical power value; the control circuit is configured to receive and compare the first optical power value and the second optical power value, and control the gain of the centralized optical amplifier based on a comparison result; the optical power feedforward unit comprises: a first optical beam splitter configured to proportionally distribute optical power of the input optical signal into two paths for output; a first photodetector configured to receive one path of optical signals distributed by the first optical beam splitter to acquire the first optical power value; when a ratio of the first optical power value and the second optical power value is less than a set value, the control circuit controls the centralized optical amplifier to decrease the gain until the ratio of the first optical power value and the second optical power value is equal to the set value; when the ratio of the first optical power value and the second optical power value is greater than the set value, the control circuit controls the centralized optical amplifier to increase the gain until the ratio of the first optical power value and the second optical power value is equal to the set value.

2. The self-adapting Raman gain compensation system according to claim 1, wherein, the optical power feedback unit comprises: a second optical beam splitter configured to proportionally distribute optical power of the optical signal output by the centralized optical amplifier into two paths for output; a second photodetector configured to receive one path of optical signals distributed by the second optical beam splitter to acquire the second optical power value.

3. The self-adapting Raman gain compensation system of claim 2, wherein: The first optical beam splitter and the second optical beam splitter are both configured to distribute according to a ratio of 95:

5.

4. The self-adapting Raman gain compensation system of claim 1, wherein: The set value is 1.

5. The self-adapting Raman gain compensation system of claim 1, wherein: The centralized optical amplifier is a semiconductor optical amplifier or an erbium-doped fiber amplifier.

6. A method for compensating a system according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: acquiring partial optical powers of the input optical signal and the optical signal output by the centralized optical amplifier; adjusting the gain of the centralized optical amplifier by the compensation device, so that a ratio of the partial optical powers of the input optical signal and the optical signal output by the centralized optical amplifier is a set value.

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