CN115622628A - Automatic gain control double-circuit EDFA and ROADM structure sharing pump - Google Patents

Abstract

The invention relates to the technical field of communication, and provides a double-path EDFA and ROADM structure for sharing automatic gain control of a pump. The double-path EDFA comprises a common pump source, a first EDFA, a second EDFA and a first wave splitter; first pump light output by the common pump source is input to a pump input end of a first EDFA to be used for signal gain of the first EDFA; the first wave splitter is used for splitting the output signal of the first EDFA to obtain second pump light, and the second pump light is input to the second EDFA to be used for signal gain of the second EDFA; and the second pump light is the pump light left after the first pump light is used for signal gain of the first EDFA. The invention uses the residual pump light in the first EDFA2 for the second EDFA3, so that the gain function of two EDFAs can be realized by one common pump source, thereby reducing the number of the pump sources needed to be used in a multi-EDFA environment by sharing the pump sources, reducing the production cost and providing a basis for the miniaturization of devices using a plurality of EDFAs.

Description

Automatic gain control double-circuit EDFA and ROADM structure sharing pump

Technical Field

The invention relates to the technical field of communication, in particular to a double-path EDFA and ROADM structure for sharing automatic gain control of a pump.

Background

With the rapid evolution of novel telecommunication services such as 5G, video on demand, virtual reality VR, mobile internet of things, DCI data communication and the like, the requirements of backbone transmission networks on bandwidth construction and bandwidth management are higher and higher. These new types of telecommunications services have higher dynamic characteristics and unpredictability than traditional telecommunications services. Therefore, a backbone network is required to be more flexible and configurable, a reconfigurable dynamic network with software capable of being configured remotely is realized, and a traditional point-to-point network structure is evolved to a ring network topology structure.

In order to implement a flexibly configurable Reconfigurable dynamic network, a ROADM (Reconfigurable Optical Add-Drop Multiplexer) node needs to be added in the ring network, and any wavelength needs to be transmitted/received in any direction or the same wavelength in different directions needs to be received or transmitted in the ROADM node. Different direction numbers determine the scale of the ROADM node, the output power of the line amplifier, the insertion loss of the WSS, the insertion loss of the MCS, and the power of the local transmitting module jointly determine the gain of the EDFA in the upper line, and the gain of the EDFA in the lower line is determined by the output power of the line amplifier, the insertion loss of the WSS, the insertion loss of the MCS, and the sensitivity of the local receiving module, which results in that the upper line and the lower line may respectively need the EDFAs with different gains.

With the development of communication technology, the existing devices are developed toward high integration and miniaturization, and the need to provide at least one pump source for each EDFA obviously limits the possibility of miniaturization of devices using multiple EDFAs, such as EDFA arrays.

In view of this, overcoming the drawbacks of the prior art is a problem to be solved urgently in the art.

Disclosure of Invention

The technical problem to be solved by the present invention is that in the prior art, at least one pump source is generally required to be provided for each EDFA, which results in a large production cost consumption and limits the possibility of miniaturization of devices using a plurality of EDFAs.

In a first aspect, the present invention provides a dual-channel EDFA with shared pumping and automatic gain control, including a common pump source 1, a first EDFA2, a second EDFA3, and a first splitter 4;

first pump light output by the common pump source 1 is input to a pump input end of the first EDFA2, so as to be used for signal gain of the first EDFA 2;

the first wave splitter 4 is disposed at a gain output end of the first EDFA2, and a pump output end of the first wave splitter 4 is connected to a pump input end of the second EDFA 3;

the first wave splitter 4 splits the output signal of the first EDFA2 to obtain second pump light, and inputs the second pump light to the second EDFA3 for signal gain of the second EDFA 3; the second pump light is the pump light left after the first pump light is used for signal gain of the first EDFA 2.

Preferably, a filter 5 is further disposed between the pump output end of the first splitter 4 and the pump input end of the second EDFA 3;

the filter 5 is configured to filter the first pump light to reject signals of a first wavelength band carried in the first pump light; wherein the first wavelength band is a wavelength band of a signal to be gained by the first EDFA 2.

Preferably, the second EDFA3 includes a plurality of erbium-doped fibers therein, and the second pump light is used for signal gain of all erbium-doped fibers in the second EDFA3.

Preferably, the second pump light is used for signal gain of all erbium-doped fibers in the second EDFA3, and specifically includes:

the pumping output end of the first wave splitter 4 is connected to the pumping input end of the target erbium-doped fiber; the target erbium-doped fiber is a first erbium-doped fiber in the pumping direction in the second EDFA 3;

a second wave splitter 6 is arranged in every two adjacent erbium-doped fibers, the second wave splitter 6 is arranged at the gain output end of the first erbium-doped fiber, and the pumping output end of the second wave splitter 6 is connected to the pumping input end of the second erbium-doped fiber;

the second wave splitter 6 is used for splitting the output signal of the first erbium-doped fiber to obtain third pump light, and the third pump light is input to the second erbium-doped fiber for signal gain of the second erbium-doped fiber; and the third pump light is the pump light left after signal gain is carried out on the first erbium-doped fiber.

Preferably, the signal output end of the second wave splitter 6 is connected to the signal input end of the second erbium-doped fiber through a flat filter 7;

the second wave splitter 6 is also used for splitting the output signal of the first erbium-doped fiber to obtain an intermediate gain signal;

the flattening filter 7 is configured to flatten the gain of the intermediate gain signal, and input the flattened intermediate gain signal to the second erbium-doped fiber, so as to perform subsequent signal gain on the intermediate gain signal.

Preferably, the two-way EDFA further includes a controller 8;

the controller 8 is configured to adjust the optical power of the first pump light according to the gain of the second EDFA3 after the last optical power adjustment until the gain of the second EDFA3 is a target gain; and when the optical power is adjusted for the first time, adjusting the optical power according to the current gain of the second EDFA3.

Preferably, an input photoelectric detection component 9 is arranged at a signal input end of the second EDFA3, and an output photoelectric detection component 10 is arranged at a signal output end of the second EDFA 3;

the input photoelectric detection component 9 is configured to detect a first optical power of an input signal of the second EDFA 3;

the output photoelectric detection component 10 is configured to detect a second optical power of an output signal of the second EDFA3, so as to calculate a gain of the second EDFA3 according to the first optical power and the second optical power.

Preferably, the controller 8 is further configured to control a switching pump of the common pump source 1, specifically,

when the first optical power is less than a preset minimum threshold and lasts for a first preset time, the controller 8 turns off the pump of the common pump source 1;

and when the first optical power is not less than a preset minimum threshold value and lasts for a second preset time, the controller 8 starts pumping the common pump source 1.

Preferably, the length of the erbium-doped fiber in the first EDFA2 is smaller than a preset length, so that the erbium-doped fiber reaches gain saturation under the action of the first pump light, and the gain of the first EDFA2 is stabilized.

In a second aspect, the present invention further provides a ROADM structure, where the ROADM structure uses the dual-path EDFA sharing automatic gain control of a pump in the first aspect, and specifically, a first EDFA2 and a second EDFA3 in the dual-path EDFA are respectively used as an add-line portion and a drop-line portion in the same direction in the ROADM structure.

The invention utilizes the fiber gain saturation which is usually avoided by technicians in the field, so that the residual pump light in the first EDFA2 is used for the second EDFA3, the gain function of two EDFAs can be realized by one common pump source 1, the number of the pump sources required to be used in a multi-EDFA environment is reduced by sharing the pump sources, the production cost is reduced, and a foundation is provided for the miniaturization of devices using a plurality of EDFAs.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an EDFA in the prior art according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a multiple EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a multiple EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a ROADM structure provided by an embodiment of the present invention;

fig. 12 is a gain profile of a dual-path EDFA sharing automatic gain control of pumps according to an embodiment of the present invention;

fig. 13 is a noise index spectrum of a two-way EDFA sharing automatic gain control of pumps according to an embodiment of the present invention.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:

1. a common pump source; 2. a first EDFA; 3. a second EDFA; 4. a first wave splitter; 5. a filter; 6. a second wave splitter; 7. a flattening filter; 8. a controller; 9. inputting a photoelectric detection component; 10. outputting a photoelectric detection component; 11. a first pump source; 12. a first photodetection component.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, the terms "inner", "outer", "longitudinal", "lateral", "upper", "lower", "top", "bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are for convenience only to describe the present invention without requiring the present invention to be necessarily constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Example 1:

an EDFA is an amplifier commonly used in communication networks, and generally consists of an erbium-doped fiber and a pump source, and the principle is as follows: under the action of the pump light, the erbium-doped fiber generates excited radiation by the inversion excitation of particles, so that the optical signal is amplified.

According to the direction of the pump source inputting the erbium-doped fiber, the EDFA can be divided into a co-directional pump type, a counter-directional pump type and a bidirectional pump type, for example, as shown in fig. 1, the EDFA is a co-directional pump type EDFA comprising an erbium-doped fiber, wherein a signal to be gained is input from a signal input end, passes through an isolator and then reaches one input end of a combiner, pump light generated by the pump source reaches the other input end of the combiner from the pump input end, and the combiner combines the signal to be gained and the pump light and then inputs the combined signal to the erbium-doped fiber, so that the signal to be gained gains in the erbium-doped fiber.

In general, in practical use, the length of the erbium-doped fiber is long enough to change the optical power of the pump light, so that the effect of changing the gain of the EDFA can be achieved.

However, when the length of the erbium-doped fiber is short enough and the power of the pump light is large enough, it may happen that the erbium-doped fiber cannot completely absorb the pump light, which may be called fiber gain saturation, so that the gain output end carries both the gained optical signal and the remaining pump light, in this case, even if the optical power of the pump light is further increased, the gain of the EDFA will be maintained within the corresponding range, and only a small amplitude fluctuation occurs, which is usually avoided by those skilled in the art.

In the prior art, at least one pump source, such as a pump laser, is usually provided for each EDFA, and when an EDFA with large gain is to be implemented, a plurality of pump sources may be provided for one EDFA, which undoubtedly increases the production cost of the EDFA. And with the development of communication technology, the existing devices are more developed towards high integration and miniaturization, and the need to provide at least one pump source for each EDFA obviously limits the possibility of miniaturization of a device using multiple EDFAs, such as a node of an EDFA array, and to solve this problem, embodiment 1 of the present invention provides a two-way EDFA sharing automatic gain control of a pump, as shown in fig. 2, including a common pump source 1, a first EDFA2, a second EDFA3, and a first demultiplexer 4.

The first pump light output by the common pump source 1 is input to the pump input end of the first EDFA2, so as to be used for signal gain of the first EDFA 2.

The first wave splitter 4 is disposed at a gain output end of the first EDFA2, and a pump output end of the first wave splitter 4 is connected to a pump input end of the second EDFA 3; the first splitter 4 splits the output signal of the first EDFA2 to obtain second pump light, and inputs the second pump light to the second EDFA3 for signal gain of the second EDFA 3; the second pump light is the pump light left after the first pump light is used for signal gain of the first EDFA 2.

Although the dashed line box corresponding to the first EDFA2 in the drawing includes the first splitter 4, for convenience of description, the scheme of the embodiment of the present invention is illustrated without dividing the first splitter 4 into the first EDFA2, and in an actual application scenario, whether the first EDFA2 includes the first splitter 4 may depend on a specific product form.

It should be noted that the signal input end, the pump input end, the gain output end and the signal output end in this embodiment do not refer to a specific port of a certain device individually, but are determined according to the device to which the device belongs, for example, two input ports may exist in the first device, where one of the two input ports is used for inputting a signal to be gained and is called a signal input end, and the other is used for inputting pump light and is called a pump input end, and the gain output end and the signal output end are different expressions of output ports at different positions, and the gain output end is used for referring to an output port of a portion of the EDFA performing gain, such as an output port corresponding to an output position of an optical fiber in the corresponding EDFA, which may carry a signal after the gain in the corresponding optical fiber and remaining pump light, and the signal output end refers to a final output port of the EDFA, such as an output port of the EDFA reached after passing through the gain output end and the flat filter 7, and the output position of the EDFA usually only has a signal after the gain. The expression is based on conventional terminology of a person skilled in the art and is not ambiguous.

The first EDFA2 and the second EDFA3 are two EDFAs independent in function, that is, the first EDFA2 and the second EDFA3 have respective signal input ends and signal output ends, and can respectively perform different degrees of gains on different signals to be gained, for example, the first EDFA2 performs gain on C-band signals with a gain size of 8dB, and the second EDFA3 performs gain on C-band signals with a gain size of 18dB.

The first wave splitter 4 further splits the wave to obtain an output gain signal, the gain signal is output from a signal output end of the first wave splitter 4, and a signal output end of the first wave splitter 4 is connected to the flat filter 7 in the first EDFA2 and finally output, so that the first EDFA2 outputs a gain signal with flat gain.

The length of the erbium-doped fiber in the first EDFA2 is smaller than a preset length, so that the erbium-doped fiber achieves gain saturation under the action of the first pump light, and the gain of the first EDFA2 is stable. And the first pump light is not completely absorbed by the erbium-doped fiber in the first EDFA2, so that the second pump light remains.

The preset length is obtained by analyzing the gain requirement of the first EDFA2 by those skilled in the art. The gain stability is relative, i.e., the gain fluctuation is maintained within a tolerable range, and does not mean that the gain is a constant value. For example, when the gain of the first EDFA2 is not more than 10dB and the output power is not more than 15dBm, the gain deviation is less than 0.5dB.

In the embodiment, the fiber gain saturation which is usually avoided by those skilled in the art is utilized, so that the remaining pump light in the first EDFA2 is used for the second EDFA3, and the two EDFAs can realize respective independent gain functions through one common pump source 1, so that the number of the pump sources required to be used in a multi-EDFA environment is reduced through the common use of the pump sources, thereby reducing the production cost and providing a basis for the miniaturization of the ROADM node.

In practical use, the first EDFA2 and the second EDFA3 usually have different gain requirements, for example, the first EDFA2 is a small gain EDFA with a gain of not more than 10dB and an output power of not more than 15dBm, and the second EDFA3 is a large gain EDFA. The first EDFA2 and the second EDFA3 are used in pairs, and the gains thereof are identical or not.

In practical use, the boundary of the wave splitting of the wave splitter may be unclear, for example, the signal to be gained by the first EDFA2 is about 1550nm, and the wavelength of the first pump light is 980nm; the first wave splitter 4 is used for separating 980nm wavelength light and 1550nm wavelength light, outputting signals after gain of 1550nm, and inputting pump light of 980nm to the second EDFA3. However, in practical use, the demultiplexer may split a part of light with a wavelength of 1550nm to a pump output end corresponding to 980nm, so that a second pump light carries a part of a gained signal, and for this problem, the present embodiment further provides the following preferred embodiments, as shown in fig. 3, which specifically includes:

and a filter 5 is arranged between the pumping output end of the first wave splitter 4 and the pumping input end of the second EDFA3.

The filter 5 is configured to filter the first pump light to reject signals of a first wavelength band carried in the first pump light; wherein, the first wavelength band is a wavelength band of a signal to be gained by the first EDFA 2.

This embodiment performs a filtering operation again by adding a filter 5 to ensure that the second pump light entering the second EDFA3 is pure and without inclusion of signal light.

When a larger gain is required for the second EDFA3, the following is usually adopted: the second EDFA3 includes a plurality of erbium-doped fibers, and the second pump light is used for signal gain of all erbium-doped fibers in the second EDFA3.

When a plurality of erbium-doped fibers exist, each erbium-doped fiber corresponds to a corresponding gain output end and a corresponding pump input end, and the gain output end of the second EDFA3 is a general term of the gain output ends of all the erbium-doped fibers.

This embodiment further provides a specific implementation manner that the second pump light is used for signal gain of all erbium-doped fibers in the second EDFA3, as shown in fig. 4, which specifically includes:

the pumping output end of the first wave splitter 4 is connected to the pumping input end of the target erbium-doped fiber; the target erbium-doped fiber is the first erbium-doped fiber in the pumping direction in the second EDFA3.

And a second wave splitter 6 is arranged in each two adjacent erbium-doped fibers, the second wave splitter 6 is arranged at the gain output end of the first erbium-doped fiber, and the pumping output end of the second wave splitter 6 is connected to the pumping input end of the second erbium-doped fiber.

The second wave splitter 6 is used for splitting the output signal of the first erbium-doped fiber to obtain third pump light, and the third pump light is input to the second erbium-doped fiber for signal gain of the second erbium-doped fiber; and the third pump light is the pump light left after signal gain is carried out on the first erbium-doped fiber.

In practical use, the first EDFA2 may also include a plurality of erbium-doped fibers, and the implementation thereof is based on the same concept as the above-described specific embodiment, and will not be described herein again.

Here, the first erbium-doped fiber and the second erbium-doped fiber are not referred to as specific erbium-doped fibers, but two adjacent erbium-doped fibers are referred to as a first erbium-doped fiber and a second erbium-doped fiber in sequence in the pumping direction. In different pairs of adjacent groups of erbium doped fibers, the same erbium doped fiber may exist as a first erbium doped fiber in one group and as a second erbium doped fiber in the other group.

For example, in an EDFA of a backward pumping type, there are 3 erbium-doped fibers, respectively fiber-1, fiber-2 and fiber-3 in the order of backward pumping direction, i.e., opposite to the signal input direction. Wherein the first erbium-doped fiber in the pumping direction of fiber-3 is called the target erbium-doped fiber, and fiber-3 is adjacent to fiber-2, then fiber-3 is the first erbium-doped fiber, fiber-2 is the second erbium-doped fiber, and fiber-2 is also adjacent to fiber-1, then fiber-2 is the first erbium-doped fiber, and fiber-1 is the second erbium-doped fiber, relative to the two adjacent erbium-doped fibers of fiber-3 and fiber-2. The second splitter 6 is not a specific splitter, but a general name of all splitters provided in two adjacent erbium-doped fibers. Similarly, the third pump light is also a generic term of the pump light branched by the second beam splitter 6.

In practical use, in the erbium-doped fiber, different gains may occur in different wavelengths of light, so that the optical powers of different wavelength signals in the finally output optical signals are different, which affects the normal operation of the ROADM node, and in order to solve this problem, there are the following preferred embodiments, as shown in fig. 4, specifically including:

the signal output end of the second wave splitter 6 is connected to the signal input end of the second erbium-doped fiber through a flat filter 7.

And the second wave splitter 6 is also used for splitting the output signal of the first erbium-doped fiber to obtain an intermediate gain signal.

The flattening filter 7 is configured to flatten the gain of the intermediate gain signal, and input the flattened intermediate gain signal to the second erbium-doped fiber, so as to perform subsequent signal gain on the intermediate gain signal.

In order to control the gain of the two-way EDFA, the present embodiment further provides the following preferred embodiments, as shown in fig. 5, which specifically include:

the two-way EDFA further comprises a controller 8.

The controller 8 is configured to adjust the optical power of the first pump light according to the gain of the second EDFA3 after the last optical power adjustment until the gain of the second EDFA3 is a target gain; and when the optical power is adjusted for the first time, adjusting the optical power according to the current gain of the second EDFA3.

It should be noted that "last optical power adjustment" described in this embodiment is relative to this optical power adjustment process, for example, three optical power adjustments have been performed until a certain time, and for convenience of description, these three optical power adjustments are referred to as: the first adjustment is the last adjustment of the second adjustment, and the second adjustment is the last adjustment of the third comparison, wherein the second adjustment adjusts the optical power according to the gain after the first adjustment, and the third adjustment adjusts the optical power according to the gain after the second adjustment until the gain of the second EDFA3 is adjusted to be the target gain.

In the adjusting process, because the erbium-doped fiber in the first EDFA2 is saturated in gain, the gain of the erbium-doped fiber is basically stable and has small fluctuation, and only the gain of the second EDFA3 is changed.

In order to obtain the gain of the EDFA, the following optional embodiments also exist, as shown in fig. 5, specifically including:

the signal input end of the second EDFA3 is provided with an input photoelectric detection component 9, and the signal output end of the second EDFA3 is provided with an output photoelectric detection component 10.

The input photo detection assembly 9 is configured to detect a first optical power of an input signal of the second EDFA3.

The output photodetection assembly 10 is configured to detect a second optical power of the output signal of the second EDFA3.

To calculate a gain of the second EDFA3 from the first optical power and the second optical power.

The input photoelectric detection component 9 and the output photoelectric detection component 10 are generally arranged through a coupler, so that the photoelectric detection does not affect the magnitude of the optical power of the normal input and output.

The present embodiment also provides the following optional embodiments for the control of the switching pump of the common pump source 1, specifically including:

the controller 8 is further configured to control a pump switch of the common pump source 1 according to the first optical power, and specifically, when the first optical power is smaller than a preset minimum threshold and lasts for a first preset time, the controller 8 switches the pump off of the common pump source 1.

And when the first optical power is not less than a preset minimum threshold value and lasts for a second preset time, the controller 8 starts pumping the common pump source 1.

The first preset time and the second preset time are obtained by a person skilled in the art according to empirical analysis.

Example 2:

in practical use, the second EDFA3 may still need larger gain and output power, and one pump source may not meet the power requirement of the second EDFA3, and the following embodiments are proposed in this embodiment, specifically:

the second pump light is used for signal gain of any erbium-doped fiber in the second EDFA3, and pump light required for signal gain of other erbium-doped fibers is provided by other pump sources (such as the first pump source 11 shown in fig. 6 or fig. 7).

In general, one pump laser is sufficient for most applications, and if the second EDFA3 needs to have a larger output power, two or more pump lasers are needed, in this case, one erbium-doped fiber of the first EDFA2 and the second EDFA3 shares a pump source, and the other erbium-doped fibers use independent pump sources, thereby forming the above-mentioned embodiment.

The present embodiment further provides a specific implementation manner, as shown in fig. 6 or fig. 7, including:

the second wave splitter 6 is connected to the pump input end of any erbium-doped fiber in the second EDFA 3; and the pump input end of each other erbium-doped fiber in the second EDFA3 is connected with a corresponding pump source.

For example, the second EDFA3 includes two erbium-doped fibers, which are respectively referred to as fiber-1 and fiber-2, wherein the fiber-1 and the first EDFA2 share a common pump source, and the fiber-2 has a separate pump source. Alternatively, the fiber-2 may be provided with a common pump source with the first EDFA2, and the fiber-1 may have a separate pump source.

In fig. 7, the signal input end and the signal output end of the first EDFA2 are further respectively provided with a photoelectric detection assembly, the photoelectric detection assemblies at the two positions have different functions from those of the input photoelectric detection assembly 9 and the output photoelectric detection assembly 10, and the photoelectric detection assemblies at the two positions are only responsible for detecting optical power and do not participate in the process of gain adjustment.

There is yet another alternative embodiment, specifically including:

the two-way EDFA further comprises a controller 8.

The controller 8 is configured to adjust the optical power of the first pump light and the optical power of the pump light of the other pump sources according to the gain of the second EDFA3 after the last optical power adjustment until the gain of the second EDFA3 is the target gain.

When the optical power of the first pump light is adjusted, the gain of the first EDFA2 fluctuates a little, and when the optical power of the pump light of other pump sources is adjusted, the gain of the first EDFA2 is not affected.

There is therefore also a preferred embodiment: as shown in fig. 8, a photoelectric detection component (e.g., a first photoelectric detection component 12 shown in fig. 8) is further disposed between the signal output end of the second splitter 6 and the signal input end of the second erbium-doped fiber, and is configured to detect the optical power of the second pump light entering the second EDFA3, and when the controller 8 adjusts the optical power, the controller also adjusts the optical power of the corresponding pump source according to the optical power of the second pump light and the gain of the second EDFA3 after the previous optical power adjustment, taking the optical power of the second pump light into consideration.

After the first photo-detection assembly 12 is introduced, the controller 8 performs the optical power adjustment, and there are two alternative embodiments:

the first method is as follows: keeping the optical power of the first pump light unchanged, determining the optical power of the first pump source 11 required by the second EDFA3 to reach the target gain according to the optical power of the second pump light and the current gain of the second EDFA3 by the controller 8, and adjusting the optical power of the first pump source 11 to make the second EDFA3 reach the target gain.

The method can ensure that the gain of the first EDFA2 is absolutely stable, and reduce the fluctuation of the gain, and the method can accurately calculate the required optical power of the first pump source 11 due to the acquisition of the accurate optical power of the second pump light, thereby realizing accurate adjustment, reducing the adjustment times required until the gain of the second EDFA3 is the target gain, and shortening the gain adjustment time.

The second method comprises the following steps:

according to the power of the second pump light during the last adjustment and the corresponding current gain of the second EDFA3, the amount of the power of the second pump light required to be adjusted when the second EDFA3 wants to reach the target gain is calculated, and then the light power of the public pump source 1 is adjusted.

The third method comprises the following steps:

according to the power of the second pump light, the corresponding current gain of the second EDFA3 and the gain stability requirement of the first EDFA2, the light power of the common pump source 1 is determined, after the light power of the common pump source 1 is determined, the light power of the first pump source 11 is determined, and therefore the common pump source 1 and the first pump source 11 are adjusted, so that balance is kept between the gain stability of the first EDFA2 and the minimum light power of the pump light required by the whole body, and finally the gain of the second EDFA3 is adjusted to the target gain.

There is also a preferred embodiment as shown in fig. 9, the first pump source 11 is connected to a pair of multi-optical switches, each output terminal of the optical switch is connected to a corresponding pump light transmission branch, and the pump light transmission branches are: the connection between the corresponding splitter and the pump input end of the corresponding erbium-doped fiber, such as the connection between the first splitter and the pump input end of the second EDFA3 in fig. 9, and the connection between the second splitter 6 and the pump input end of the second erbium-doped fiber, the output end of the optical switch is connected to the corresponding pump light transmission branch, so that when the corresponding output end of the optical switch is opened, the pump light of the first pump source 11 is merged into the corresponding pump light transmission branch and finally input to the corresponding pump input end, and in fig. 9, the merging position of the corresponding output end of the optical switch and the pump light transmission branch is represented in the form of a combiner, which is only for representing that the light is merged into the branch from the corresponding output end of the optical switch, and in actual use, whether a combiner or other devices are needed to be analyzed by those skilled in the art.

Wherein, in every pump light transmission branch road, be provided with the photoelectric detection subassembly, controller 8 is according to the switching of photoelectric detection subassembly control photoswitch's output, and is specific, according to the pumping direction, when photoelectric detection subassembly detects and does not have remaining pump light in the corresponding branch road, open the photoswitch output that corresponds, make first pump source 11 provide the pump light for corresponding erbium-doped fiber. The present embodiment is also applicable to a multiple-way EDFA, and the specific structure of the multiple-way EDFA and the specific implementation of the embodiment will be described in embodiment 3, which are not described herein again.

Example 3:

in practical applications, more than two EDFAs may be required, and in order to further reduce the production cost, as a preferred embodiment, based on the same concept as that of embodiment 1, more than two EDFAs may be made to share a pump source, so that this embodiment provides a multiple EDFA sharing automatic gain control of a pump, as shown in fig. 10, where there are N EDFAs in the multiple EDFAs, and a demultiplexer is disposed between each EDFA, specifically:

the first pump light output by the common pump source 1 is input to the pump input end of the first EDFA, so as to be used for signal gain of the first EDFA.

The kth wave splitter is arranged at the gain output end of the kth EDFA, and the pump output end of the kth wave splitter is connected to the pump input end of the (k + 1) th EDFA; wherein k is a positive integer, k is greater than or equal to 1 and k is less than N; n is a positive integer and is not less than 2.

The kth wave splitter splits the output signal of the kth EDFA to obtain kth +1 pump light, and the kth +1 pump light is input to the kth +1 EDFA for signal gain of the kth +1 EDFA; and the (k + 1) th pump light is the pump light left after the kth pump light is used for signal gain of the kth EDFA.

The length of the erbium-doped fiber in the kth EDFA is smaller than a preset length, so that the erbium-doped fiber achieves gain saturation under the action of the kth pump light, and the gain of the kth EDFA is stable. And the kth pump light is not completely absorbed by the erbium-doped fiber in the kth EDFA, so that the kth +1 pump light is remained.

In this embodiment, k may be regarded as traversal of all values in a range of greater than or equal to 1 and less than N, so that a corresponding demultiplexer is disposed between every two adjacent EDFAs, thereby implementing multiplexing of multiple EDFAs of the common pump source 1.

It should be noted that, when N is 2, the present embodiment is the same as embodiment 1, and the preferred embodiments in embodiment 1 are also applicable to the present embodiment, and when N is greater than 2, the present embodiment can be understood as a further extension scheme based on embodiment 1 or embodiment 2, so that the preferred embodiments in embodiments 1 and 2 should also be applicable to the present embodiment, and based on the same concept as that of the preferred embodiments in embodiments 1 or 2, the extended embodiments due to the increased number of EDFAs should also be included in the protection scope of the present invention.

In the multiple EDFA, when the optical switch described in embodiment 2 is connected, specifically, for convenience of description, corresponding pump light branches connected to the pump input ends of the erbium-doped fibers in the multiple EDFA are sequentially referred to as a 1 st branch, a2 nd branch, …, and an N-1 st branch according to a pump direction, each output end of the optical switch is correspondingly connected to the corresponding branch, and a photodetection component is disposed on each branch, when the photodetection component of the corresponding branch detects optical power, it is described that residual pump light exists after the gain of the erbium-doped fiber, the output end of the corresponding optical switch is turned off, and the residual pump light branches are connected through the branches and input to the pump input end of the next erbium-doped fiber to provide gain for the next erbium-doped fiber, so that the erbium-doped fibers share one pump source.

When the photodetection module of the corresponding branch detects no optical power, it indicates that the pump light has been absorbed after the gain of the erbium-doped fiber, and there is no remaining pump light, the output end of the corresponding optical switch is opened, so that the first pump source 11 provides pump light to the next erbium-doped fiber.

For example, there are 6 branches in the multiple EDFA, where the photodetection component on the 4 th branch detects no optical power, and then there are remaining pump lights on the 1 st, 2 nd, and 3 st branches, without opening the corresponding optical switch output port, and the 2 nd, 3 rd, and 4 th erbium-doped fibers corresponding to the correspondingly connected pump output ports share a common pump source, and the optical switch output port on the 4 th branch is opened to provide pump light for the 5 th erbium-doped fiber corresponding to the 4 th branch, and the remaining pump light after the 5 th erbium-doped fiber gains enters the 5 th branch to provide pump light for the 6 th erbium-doped fiber, and similarly, the pump light of the 7 th erbium-doped fiber comes from the remaining pump light after the 6 th erbium-doped fiber gains, i.e., the 5 th, 6 th, and 7 th erbium-doped fibers share a pump source, until the detecting optoelectronic component of the corresponding branch detects that the pump light is exhausted, i.e., there is no remaining pump light, and then the optical switch output port corresponding to the branch is opened.

Example 4:

after providing the dual-channel EDFA sharing automatic gain control of pumps described in embodiment 1, the embodiment of the present invention further provides a ROADM structure, so as to make relevant descriptions on the use angle side of the corresponding structure function in embodiment 1, and further make relevant deep analysis on the design principle. It should be noted that the device structure in embodiment 1 is applicable to this embodiment, and the structure thereof will not be described again in this embodiment.

A ROADM structure using the dual-path EDFA sharing automatic gain control of pumps described in embodiment 1, in particular,

and a first EDFA2 and a second EDFA3 in the double-path EDFA are respectively used for an add-in part and a drop-out part in the same direction in the ROADM.

Or the ROADM uses the multiple EDFA sharing automatic gain control of the pump described in embodiment 2.

For example, a two-way EDFA is used as shown in fig. 10, in which a small gain EDFA (which may be understood as the first EDFA2 in embodiment 1) and a large gain EDFA (which may be understood as the second EDFA3 in embodiment 1) use a C-band (1528 to 1568 nm) or a C-band extension band (1524 to 1573 nm), the signal band isolation of the two-way EDFA is greater than 70dB, the gain of the small gain EDFA is not greater than 10dB, and the output power is not greater than 13dBm.

The controller 8 performs gain control on the large gain EDFA according to an input photoelectric detector (which may be regarded as the input photoelectric detection module 9 in embodiment 1) and an output photoelectric detector (which may be regarded as the output photoelectric detection module 10 in embodiment 1), that is, calculates current gain = (output power (mW) -ASE (mW))/input power (mW)) first, and adjusts the optical power of the pump source according to the current gain until the gain of the large gain EDFA reaches a target gain.

A ROADM structure composed of the above two-way EDFAs is shown in fig. 11, where the two-way EDFAs are used in pairs and responsible for signal amplification of upper and lower channels in the same direction in the ROADM node.

The ROADM structure is shown in fig. 11, and includes WSSs with 4 downward add-lines in directions, EDFA arrays with downward add-lines in each direction, and a multi-dimensional optical switch MCS, where four lines on the left side are the drop part of the MCS, and four lines on the right side are the add part of the MCS; in the up-down EDFAs, an up-down EDFA and a down-down EDFA in the same direction are used in pairs. The lower WSS and the upper WSS in different directions are also connected with each other, the lower WSS in the same direction is connected with the lower EDFA in the same direction, then connected with the lower MCS, and finally connected with a receiving unit Rx1 … … Rxn; the local transmitting unit Tx1 … … Txn is connected with the ascending MCS, then connected with the ascending EDFA in each direction, and finally connected with the ascending WSS in the direction.

In this embodiment, the gain of each small gain EDFA is 8dB, and the gain of each large gain EDFA is 18dB. The method mainly realizes the gain control of the small-gain EDFA indirectly by a conventional mode of controlling the 18dB gain EDFA.

Fig. 12 is a gain spectrum of two amplifiers controlled by the method, and fig. 13 is a noise index spectrum of two amplifiers controlled by the method, and it can be found by the illustration that the effect of simultaneously realizing gain control of two amplifiers by controlling one amplifier is ideal, and no obvious change is found in both gain and noise index.

In this embodiment, the number of pumps can be reduced, the volume of the EDFA array can be reduced, and the cost can be reduced by using the mode that the EDFAs used in pairs in the ROADM network node share the pumps. Two amplifiers sharing a pump can fully functionally implement all the functions of a single pump control amplifier. The small-gain EDFA which is pumped firstly in the shared pump amplifier has better noise index, namely transient performance, two amplifiers only carry out gain control through one EDFA with larger gain, the pump power of the other small-gain EDFA varies within a certain range, the variation range of the pump power can be ensured, and the gain performance can be fully ensured. Meanwhile, the two amplifiers are responsible for the up-and-down amplification in the same direction, and input signals are generated and disappeared simultaneously, so that the Los function of the amplifiers can be ensured.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A double-path EDFA with automatic gain control of shared pumping is characterized by comprising a common pumping source (1), a first EDFA (2), a second EDFA (3) and a first wave splitter (4);

a first pump light output by the common pump source (1) is input to a pump input of the first EDFA (2) for signal gain of the first EDFA (2);

the first wave splitter (4) is arranged at a gain output end of the first EDFA (2), and a pumping output end of the first wave splitter (4) is connected to a pumping input end of the second EDFA (3);

the first wave splitter (4) is used for splitting the output signal of the first EDFA (2) to obtain second pump light, and the second pump light is input to the second EDFA (3) and used for signal gain of the second EDFA (3); and the second pump light is the pump light left after the first pump light is used for signal gain of the first EDFA (2).

2. A pumped automatic gain controlled two-way EDFA according to claim 1, wherein between the pump output of the first splitter (4) and the pump input of the second EDFA (3) a filter (5) is further provided;

the filter (5) is used for filtering the first pump light to reject signals of a first waveband carried in the first pump light; wherein the first wave band is a wave band of a signal to be gained of the first EDFA (2).

3. The commonly pumped, automatic gain controlled, two-way EDFA according to claim 1, characterized in that said second EDFA (3) comprises a plurality of erbium doped fibers, said second pump light being used for signal gain of all erbium doped fibers of said second EDFA (3).

4. A pumped, automatic gain controlled two-way EDFA according to claim 3, wherein the second pump light is used for signal gain of all erbium doped fibers in the second EDFA (3), in particular comprising:

the pumping output end of the first wave splitter (4) is connected to the pumping input end of the target erbium-doped fiber; the target erbium-doped fiber is a first erbium-doped fiber in the pumping direction in the second EDFA (3);

a second wave splitter (6) is arranged in each two adjacent erbium-doped fibers, the second wave splitter (6) is arranged at the gain output end of the first erbium-doped fiber, and the pumping output end of the second wave splitter (6) is connected to the pumping input end of the second erbium-doped fiber;

the second wave splitter (6) is used for splitting the output signal of the first erbium-doped fiber to obtain third pump light, and the third pump light is input to the second erbium-doped fiber and used for signal gain of the second erbium-doped fiber; and the third pump light is the pump light left after signal gain is carried out on the first erbium-doped fiber.

5. A shared-pump automatic gain controlled two-way EDFA according to claim 4, wherein the signal output of the second splitter (6) is connected to the signal input of the second erbium doped fiber through a flattening filter (7);

the second wave splitter (6) is also used for splitting the output signal of the first erbium-doped optical fiber to obtain an intermediate gain signal;

the flat filter (7) is used for performing gain flattening on the intermediate gain signal, and inputting the intermediate gain signal after gain flattening to the second erbium-doped fiber so as to perform subsequent signal gain on the intermediate gain signal.

6. The dual EDFA sharing automatic gain control of pumps of claim 1, further comprising a controller (8);

the controller (8) is configured to adjust the optical power of the first pump light according to the gain of the second EDFA (3) after the last optical power adjustment until the gain of the second EDFA (3) is a target gain; and when the optical power is adjusted for the first time, the optical power is adjusted according to the current gain of the second EDFA (3).

7. The shared-pump automatic gain-controlled two-way EDFA of claim 6, wherein the signal input end of the second EDFA (3) is provided with an input photoelectric detection component (9), and the signal output end of the second EDFA (3) is provided with an output photoelectric detection component (10);

the input photoelectric detection component (9) is used for detecting first optical power of an input signal of the second EDFA (3);

the output photoelectric detection component (10) is used for detecting second optical power of an output signal of the second EDFA (3) so as to calculate gain of the second EDFA (3) according to the first optical power and the second optical power.

8. A two-way EDFA for automatic gain control of a shared pump according to claim 7, wherein the controller (8) is further adapted for controlling a switching pump of the common pump source (1), in particular,

when the first optical power is smaller than a preset minimum threshold value and lasts for a first preset time, the controller (8) turns off the pump of the common pump source (1);

and when the first optical power is not less than a preset minimum threshold value and lasts for a second preset time, the controller (8) starts pumping the common pumping source (1).

9. A shared-pump automatic gain controlled two-way EDFA according to any of claims 1-8, characterized in that the length of the erbium doped fiber in the first EDFA (2) is smaller than a preset length, such that the erbium doped fiber reaches gain saturation under the effect of the first pump light to stabilize the gain of the first EDFA (2).

10. ROADM structure, characterized in that it uses a two-way EDFA sharing automatic gain control of pumps according to any of claims 1-9, in particular a first EDFA (2) and a second EDFA (3) of said two-way EDFA as add part and drop part, respectively, in the same direction in the ROADM structure.

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