A detection structure and method for feedforward pump failure in L-band optical fiber amplifier

Abstract

The present invention discloses a detection structure and method for feedforward pump failure in an L-band optical fiber amplifier, wherein a C / L band thin film filter is added before an ordinary output monitoring PD. When the feedforward pump fails, the inversion rate of the front-stage erbium fiber decreases sharply, thereby generating strong absorption of the signal light. Without the entry of signal light, the rear-stage erbium fiber can only generate C-band stimulated spontaneous radiation under the stimulation of the feedback pump, but cannot generate effective L-band signals. By adding a C / L band filter to the output monitoring PD branch, C-band stimulated spontaneous radiation can be prevented from entering the PD. The output monitoring PD triggers a software error due to the lack of L-band signal power. The present invention is compatible with existing designs and is very easy to promote.

Description

Technical Field

[0001] The present invention relates to the field of optics, and in particular to a detection structure and method for feedforward pump failure in an L-band optical fiber amplifier. Background Art

[0002] The existing detection methods on the market are mainly to add an additional PD behind the pump to achieve monitoring. This adds additional cost components and circuit costs. It also increases the complexity of the circuit. The second method is to use the backlight detection photodiode inside the pump. However, the photodiode has poor accuracy, changes greatly with life, and is easily affected by the external fiber state (accepts changes in the polarization state of light), which is very easy to produce false alarms, and the actual effect is not ideal. At the same time, for the new dual-chip pump, this method is even more ineffective.

[0003] In order to meet the rapidly growing capacity demand of optical communication networks, the signal capacity has been expanded to the L-band, and new L-band fiber amplifiers have been deployed on a large scale. The L-band fiber amplifier has a complex design structure and high power consumption, and more and more feedforward pumps are introduced into the design. Although the feedforward pump has a simple structure, it is difficult to locate the failure in time due to the lack of closed-loop monitoring and effective capture methods. This has caused serious problems such as failure and downtime in the existing network. Summary of the invention

[0004] The object of the present invention is to provide a low-cost, high-accuracy detection structure and method for feedforward pump failure in an L-band optical fiber amplifier.

[0005] The technical solution adopted by the present invention is:

[0006] A detection structure for feedforward pump failure in an L-band optical fiber amplifier. The optical fiber amplifier comprises a feedforward controller, a PI controller, an input PD and an output PD. The input of the optical fiber amplifier is connected to the common end of a first optical splitter. The first optical splitter port of the first optical splitter is connected to an input end of a first combiner. The second optical splitter port of the first optical splitter is connected to the input end of the input PD. The electrical output port of the input PD is connected to the input end of the feedforward controller. The output end of the feedforward controller is connected to the feedforward pump. The output of the feedforward pump is connected to the other input end of the first combiner. The output end of the first combiner is connected to a front-stage erbium fiber. The output end of the front-stage erbium fiber is connected to an input end of the second combiner. The electrical output port of the input PD is also connected to the output end of the PI controller. The input end of the PI controller is connected to the output end of the output PD, the output end of the PI controller is connected to the feedback pump, the output end of the feedback pump is connected to the other input end of the second combiner, the output end of the second combiner is connected to the rear-stage erbium fiber, the output end of the rear-stage erbium fiber is connected to the common end of the second optical splitter, the first optical splitting port of the second optical splitter is connected to the output end of the optical fiber amplifier, the second optical splitting port of the second optical splitter is connected to the output PD through a C / L thin film filter, the C / L thin film filter is used to prevent the stimulated spontaneous radiation of C-BAND from entering the output PD, and the output PD is configured with monitoring software, which issues a feedback pump failure alarm when the current value of the feedback pump is greater than the maximum current value or greater than 2 times the normal working current value.

[0007] Furthermore, the output end of the front-stage erbium fiber is connected to an input end of the second combiner through a gain flattening filter.

[0008] Furthermore, the present invention also discloses a method for detecting feedforward pump failure in an L-band optical fiber amplifier, which comprises the following steps:

[0009] Step 1: Add a C / L filter to the input front end of the output monitoring PD of the L-band fiber amplifier.

[0010] Step 2, obtain the current value of the feedback pump and the normal working current value at the corresponding moment,

[0011] Step 3, respectively judging whether the current value of the feedback pump obtained is greater than the maximum current value, and judging whether the current value of the feedback pump is greater than 2 times the normal working current value;

[0012] Step 4: When the current value of the feedback pump is greater than the maximum current value or greater than twice the normal working current value, a feedback pump failure alarm is triggered.

[0013] Furthermore, the normal operating current value in step 2 is obtained during production testing and recorded in the module memory for determination.

[0014] Furthermore, the maximum current value of step 3 is 1090 mA.

[0015] Furthermore, the failure alarm in step 4 is issued as a pop-up window alarm by the software for monitoring the output PD.

[0016] The present invention adopts the above technical solution and adds a C / L band thin film filter before the ordinary output monitoring PD. When the forward feed pump fails, the inversion rate of the front-stage erbium fiber drops sharply, resulting in strong absorption of the signal light. Without the entry of signal light, the rear-stage erbium fiber can only generate C-band stimulated spontaneous radiation under the stimulation of the feedback pump, but cannot generate effective L-band signals. By adding a C / L band filter to the output monitoring PD branch, C-band stimulated spontaneous radiation can be prevented from entering the PD. The output monitoring PD triggers a software error due to the lack of L-band signal power.

[0017] The present invention simply adds a C / L thin film filter to capture feedforward pump failure in a complex L-band amplifier using an existing PD, thereby avoiding the increase of additional costs, avoiding complex circuit design, being compatible with existing designs, and being easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments;

[0019] Figure 1 A schematic diagram of a detection structure for feedforward pump failure in an L-band optical fiber amplifier of the present invention;

[0020] Figure 2 A schematic diagram of test results of a method for detecting feedforward pump failure in an L-band optical fiber amplifier according to the present invention;

[0021] Figure 3 The present invention is a schematic diagram of an alarm logic flow of a method for detecting feedforward pump failure in an L-band optical fiber amplifier. DETAILED DESCRIPTION

[0022] like Figures 1 to 3As shown in one, the present invention discloses a detection structure for feedforward pump failure in an L-band optical fiber amplifier. The optical fiber amplifier includes a feedforward controller FF, a PI controller, an input PD and an output PD. The input end IN of the optical fiber amplifier is connected to the common end of the first optical splitter A1, the first optical splitter port of the first optical splitter A1 is connected to an input end of the first combiner B1, the second optical splitter port of the first optical splitter A1 is connected to the input end of the input PD (Input PD), an output end of the input PD (Input PD) is connected to the input end of the feedforward controller FF, the output end of the feedforward controller FF is connected to the feedforward pump Pump 1, the output of the feedforward pump Pump 1 is connected to the other input end of the first combiner B1, the output end of the first combiner B1 is connected to the front-stage erbium fiber D1, and the output end of the front-stage erbium fiber D1 is connected to an input end of the second combiner B2; the other output end of the input PD (Input PD) is connected to the input end of the PI controller, the feedback end of the PI controller is connected to the output end of the output PD, the output end of the PI controller is connected to the feedback pump Pump 2, and the feedback pump Pump The output end of 2 is connected to the other input end of the second combiner B2, the output end of the second combiner B2 is connected to the rear-stage erbium fiber D2, the output end of the rear-stage erbium fiber D2 is connected to the common end of the second optical splitter, the first optical splitter port of the second optical splitter is connected to the output end OUT of the optical fiber amplifier, and the second optical splitter port of the second optical splitter is connected to the output PD through a C / L thin film filter. The C / L thin film filter is used to prevent the stimulated spontaneous radiation of C-BAND from entering the output PD. The output PD is configured with monitoring software. The monitoring software sends a feedback pump Pump 2 failure alarm when the current value of the feedback pump Pump 2 is greater than the maximum current value or greater than 2 times the normal working current value.

[0023] Furthermore, the output end of the front-stage erbium fiber D1 is connected to an input end of the second combiner B2 through a gain flattening filter C.

[0024] Furthermore, the present invention also discloses a method for detecting failure of a feedforward pump Pump 1 in an L-band optical fiber amplifier, which comprises the following steps:

[0025] Step 1: Add a C / L filter to the input front end of the output monitoring PD of the L-band fiber amplifier.

[0026] Step 2, obtain the current value of the feedback pump Pump 2 and the normal working current value at the corresponding moment. The normal working current value is obtained during the production test and recorded in the module memory for the module software to judge.

[0027] Step 3, respectively determine whether the current value of the feedback pump Pump 2 obtained is greater than the maximum current value, the maximum current value refers to the maximum nominal working current of the feedback pump Pump 2, and at the same time determine whether the current value of the feedback pump Pump 2 is greater than 2 times the normal working current value;

[0028] Step 4: When the current value of the feedback pump Pump 2 is greater than the maximum current value or greater than 2 times the normal working current value, the feedback pump Pump 2 failure alarm is triggered. Table 1 is a comparison table of test results of the detection method of the failure of the feedforward pump Pump 1 in the L-band fiber amplifier. Specifically, the alarm test result diagram is shown in FIG. Figure 2 shown.

[0029] Table 1 - Comparison of test results of detection methods for failure of feedforward pump Pump 1 in L-band fiber amplifier

[0030]

[0031] Furthermore, the normal operating current value in step 2 is obtained during production testing and recorded in the module memory for determination.

[0032] Furthermore, the maximum current value of step 3 is 1090 mA.

[0033] Furthermore, the failure alarm in step 4 is issued as a pop-up window alarm by the software for monitoring the output PD.

[0034] The present invention adopts the above technical solution and adds a C / L band thin film filter before the ordinary output monitoring PD. Figure 2 As shown in the figure, when the front-stage pump Pump 1 fails, the inversion rate of the front-stage erbium fiber D1 decreases sharply, resulting in strong absorption of the signal light. Without the entry of signal light, the rear-stage erbium fiber D2 can only generate C-band stimulated spontaneous radiation under the stimulation of the feedback pump Pump 2, but cannot generate effective L-band signals. By adding a C / Lband filter to the output monitoring PD branch, the C-band stimulated spontaneous radiation can be prevented from entering the PD. The output monitoring PD triggers a software error due to the lack of L-band signal power. As compensation, the feedback pump Pump 2 (pump 2) will be driven to the maximum current (>1090mA), which is much higher than the current required for normal working conditions. Even under the minimum power condition, the feedback pump Pump 2 requires 3 times the operating current, and timely alarm of failure can be achieved with the software alarm logic.

[0035] The present invention simply adds a C / L thin film filter, and can use the existing PD in a complex L-band amplifier to capture the failure of the feedforward pump Pump 1. It avoids the increase of additional costs, avoids complex circuit design, is compatible with existing designs, and is very easy to promote.

[0036] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A detection structure for feedforward pump failure in an L-band optical fiber amplifier, the optical fiber amplifier comprises a feedforward controller, a PI controller, an input PD and an output PD, the input of the optical fiber amplifier is connected to the common end of a first optical splitter, the first optical splitter port of the first optical splitter is connected to an input end of a first combiner, the second optical splitter port of the first optical splitter is connected to the input end of the input PD, the electrical output port of the input PD is connected to the input end of the feedforward controller, the output end of the feedforward controller is connected to the feedforward pump, the output of the feedforward pump is connected to the other input end of the first combiner, the output end of the first combiner is connected to a front-stage erbium fiber, the output end of the front-stage erbium fiber is connected to an input end of a second combiner; the electrical output port of the input PD is simultaneously connected to the input end of the PI controller, the feedback end of the PI controller is connected to the output end of the output PD, the output end of the PI controller is connected to the feedback pump, the output end of the feedback pump is connected to the other input end of the second combiner, the output end of the second combiner is connected to the rear-stage erbium fiber, the output end of the rear-stage erbium fiber is connected to the common end of the second optical splitter, the first optical splitter port of the second optical splitter is connected to the output end of the optical fiber amplifier, characterized in that: The second splitter port of the second splitter is connected to the output PD through a C / L thin film filter. The C / L thin film filter is used to prevent the stimulated spontaneous radiation of the C-BAND from entering the output PD. The output PD is configured with monitoring software. The monitoring software issues a feedback pump failure alarm when the current value of the feedback pump is greater than the maximum current value or greater than 2 times the normal working current value.

2. The detection structure for feedforward pump failure in an L-band optical fiber amplifier according to claim 1, characterized in that: The output end of the front-stage erbium fiber is connected to an input end of the second combiner through a gain flat filter.

3. A method for detecting feedforward pump failure in an L-band optical fiber amplifier, using the detection structure for feedforward pump failure in an L-band optical fiber amplifier according to claim 1, characterized in that: The detection method includes the following steps: Step 1: Add a C / L filter to the input front end of the output monitoring PD of the L-band fiber amplifier. Step 2, obtaining the current value of the feedback pump and the normal working current value at the corresponding moment; Step 3, respectively judging whether the current value of the feedback pump obtained is greater than the maximum current value, the maximum current value refers to the maximum nominal working current of the feedback pump, and judging whether the current value of the feedback pump is greater than 2 times the normal working current value; Step 4: When the current value of the feedback pump is greater than the maximum current value or greater than twice the normal working current value, a feedback pump failure alarm is triggered.

4. The method for detecting feedforward pump failure in an L-band optical fiber amplifier according to claim 3, characterized in that: The normal operating current value in step 2 is obtained during production testing and recorded in the module memory for judgment.

5. The method for detecting feedforward pump failure in an L-band optical fiber amplifier according to claim 3, characterized in that: The maximum current value of step 3 is 1090mA.

6. The method for detecting feedforward pump failure in an L-band optical fiber amplifier according to claim 3, characterized in that: The failure alarm in step 4 is popped up by the software used to monitor the output PD.

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