CN111370978A - Optical path structure and method for gain slope real-time detection of erbium-doped fiber amplifier - Google Patents
Optical path structure and method for gain slope real-time detection of erbium-doped fiber amplifier Download PDFInfo
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Abstract
The invention provides an optical path structure for real-time detection of gain slope of an erbium-doped fiber amplifier, which comprises: two filters, two optical power monitoring devices; the two filters are used for respectively extracting out-of-band short-wave spontaneous radiation noise and out-of-band long-wave spontaneous radiation noise in the output of the EDFA main body; the two optical power monitoring devices are used for respectively detecting the out-of-band short-wave spontaneous radiation noise power and the out-of-band long-wave spontaneous radiation noise power; the common end of the first filter is used for accessing the output of the EDFA body or one part of the output of the EDFA body; the reflection end of the first filter is connected with the common end of the second filter; the transmission end of the first filter is connected with the first optical power monitoring device, and the transmission end of the second filter is connected with the second optical power monitoring device. The invention also provides a real-time detection method for the gain slope of the erbium-doped fiber amplifier.
Description
Technical Field
The invention relates to an Erbium-Doped Fiber Amplifier (EDFA), in particular to an optical path structure for real-time detection of Gain Tilt.
Background
The EDFA is a novel device applied to an optical fiber transmission system in the 90 s of the 20 th century, optical signals such as digital signals, analog signals and the like can be amplified in the 1528-1570 nm waveband after erbium ions are activated, the code type and the speed are transparent, and the popularization and application of the EDFA bring a revolution to the optical fiber communication technology.
When the EDFA is used for a Dense Wavelength Division Multiplexing (DWDM) system, the gain of each Wavelength can be different, and the linear fitting function G of the gain and the Wavelength can be obtained by performing linear fitting on the Wavelength and the gainline(λi) Bringing the termination and start wavelengths into Gline(λi) The corresponding gain is calculated, the gain difference of which is defined as the gain slope (GT: gain Tilt). The mathematical formula is as follows:
wherein G isline(λi) Is a linear fit function of gain and wavelength, k and c are the slope and intercept, respectively, of equation (1); lambda [ alpha ]iRepresents the ith wavelength; starting wavelength of λ0Terminating wavelength of λn(ii) a Wherein the Gain (Gain: G) and GT units are both dB; the wavelength (λ) is in nm;
the fitting diagram is shown in figure (1);
GT is an important parameter of EDFA, and is designed to have different values for different transmission systems and transmission distances, and for EDFAs with Automatic Gain Control (AGC), an internal Variable Attenuator (VOA) is generally used to adjust GT. The VOA attenuation amount and the GT form a certain mathematical relation, under the condition that the amplifier normally works, the theoretical design value of the GT can be obtained by the VOA attenuation amount, but the real-time real value of the GT cannot be obtained, even if the actual value of the GT deviates from the design requirement, even if an error occurs, the real value of the GT cannot be known.
At present, a real output spectrum can be obtained by scanning through a wavelength monitoring module or a spectrum analyzer, and then a GT actual value is obtained, but the price of the wavelength monitoring module is very high and needs to be supported by board card hardware and software. The spectrum analyzer has very high cost and large volume, is mainly used for testing products, has strict requirements on the environmental temperature, and is not suitable for being used in actual places.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an optical path structure for the gain slope real-time detection of an erbium-doped fiber amplifier. The embodiment of the invention adopts the technical scheme that:
an optical path structure for gain slope real-time detection of an erbium-doped fiber amplifier, comprising: two filters, two optical power monitoring devices;
the two filters are used for respectively extracting out-of-band short-wave spontaneous radiation noise and out-of-band long-wave spontaneous radiation noise in the output of the EDFA main body; the two optical power monitoring devices are used for respectively detecting the out-of-band short-wave spontaneous emission noise power and the out-of-band long-wave spontaneous emission noise power.
Further, the air conditioner is provided with a fan,
the two filters comprise a first filter and a second filter, and the two optical power monitoring devices comprise a first optical power monitoring device and a second optical power monitoring device;
the common end of the first filter is used for accessing the output of the EDFA body or one part of the output of the EDFA body; the reflection end of the first filter is connected with the common end of the second filter; the transmission end of the first filter is connected with the first optical power monitoring device, and the transmission end of the second filter is connected with the second optical power monitoring device;
and the transmission wavelength of one filter is the out-of-band short wavelength of the signal wavelength of the EDFA body, and the transmission wavelength of the other filter is the out-of-band long wavelength of the signal wavelength of the EDFA body.
Further, in the present invention,
for the filter with the transmission wavelength of the short wavelength outside the band, the transmission center of the filter is 4nm to 5nm away from the shortest wavelength of the signal wavelength of the EDFA main body;
for the filter with the transmission wavelength of the out-of-band long wavelength of the signal wavelength of the EDFA body, the transmission center of the filter is 4nm to 5nm above the longest wavelength of the signal wavelength of the EDFA body;
the transmission wavelength bandwidths of the two filters are respectively 1 nm-3 nm.
In particular, the amount of the solvent to be used,
the common end of the first filter is connected with the output end of the EDFA main body; the reflecting end of the second filter is used as a new output end of the erbium-doped fiber amplifier;
the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
Or, specifically, the optical path structure for the gain slope real-time detection of the erbium-doped fiber amplifier further comprises a detection optical splitter;
the common end of the detection optical splitter is connected with the output end of the EDFA main body, and the main output end of the detection optical splitter is used as a new output end of the erbium-doped fiber amplifier; the auxiliary output end of the detection optical splitter is connected with the common end of the first filter;
the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
Further, in the present invention,
the second filter is provided with a reflection end, and the reflection end of the second filter is connected with the optical fiber wound by a small circle or connected with the attenuation loss of more than 20 dB; or the second filter is a 1 x 1 device, namely, only a public end and a transmission end.
Or, specifically, the optical path structure for the gain slope real-time detection of the erbium-doped fiber amplifier further includes a third filter;
the common end of the third filter is connected with the output end of the EDFA main body, and the transmission end of the third filter is used as the new output end of the erbium-doped fiber amplifier; the reflection end of the third filter is connected with the common end of the first filter;
the transmission wavelength of the third filter is the in-band signal wavelength of the EDFA main body, and other wavelengths are the reflection wavelengths of the EDFA main body; the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
Further, in the present invention,
the second filter is provided with a reflection end, and the reflection end of the second filter is connected with the optical fiber wound by a small circle or connected with the attenuation loss of more than 20 dB; or the second filter is a 1 x 1 device, namely, only a public end and a transmission end.
Or, specifically, the optical path structure for the gain slope real-time detection of the erbium-doped fiber amplifier further comprises a detection optical splitter;
the common end of the detection optical splitter is connected with the auxiliary output end of the output optical splitter in the EDFA main body; the main output end of the detection optical splitter is connected with an output end optical power monitoring device in the EDFA main body, and the auxiliary output end of the detection optical splitter is connected with the common end of the first filter;
the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
Under a constant gain control mode, the shape of a gain spectrum of the erbium-doped fiber amplifier is basically kept unchanged when different input powers are input, and the shape of a spontaneous radiation noise spectrum is also basically kept unchanged;
the embodiment of the invention also provides a method for detecting the gain slope of the erbium-doped fiber amplifier in real time, which comprises the following steps:
defining the difference value of the out-of-band short-wave spontaneous emission noise power and the out-of-band long-wave spontaneous emission noise power as an out-of-band ASE power difference; a certain relation exists between the out-of-band ASE power difference and the gain slope GT;
and fitting to obtain a calibration relation between the out-of-band ASE power difference and the gain slope, calculating to obtain a real-time out-of-band ASE power difference through detecting the out-of-band short-wave spontaneous emission noise power and the out-of-band long-wave spontaneous emission noise power of the EDFA main body in real time, and obtaining the real-time gain slope according to the calibration relation between the out-of-band ASE power difference and the gain slope obtained through fitting.
The invention has the advantages that:
1) the structure of the light path is simple, and corresponding optical devices are only added at the output end on the premise of not changing the structure of the light path of the EDFA main body.
2) The filter selects a suitable transmission wavelength, and the influence of the noise floor of the system can be ignored.
3) The original control mode of the EDFA main body is not changed.
Drawings
Fig. 1 is a schematic diagram of the definition of the gain tilt GT of the present invention.
Fig. 2 is a schematic diagram of a conventional EDFA as an erbium-doped fiber amplifier.
Fig. 3 is a schematic structural diagram of a first embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a second embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a third embodiment of the present invention.
Fig. 6 is a schematic structural diagram of a fourth embodiment of the present invention.
Fig. 7 is a schematic structural diagram of a fifth embodiment of the present invention.
FIG. 8 is a schematic diagram of quadratic curve fitting according to an embodiment of the present invention.
Detailed Description
The invention is further illustrated by the following specific figures and examples.
In order to clearly show the meaning of the optical path structure for real-time gain slope detection and the existing erbium-doped fiber amplifier, in the embodiment described herein, the existing erbium-doped fiber amplifier is referred to as an EDFA body;
as shown in fig. 2, in the conventional EDFA main body, an output splitter 7 is connected to an output end of an EDFA amplification section 9, a main output end of the output splitter 7 is an output end of the EDFA main body, and an auxiliary output end of the output splitter 7 is connected to a photodiode 8 for monitoring and reporting output power of the EDFA main body; the internal structure of the conventional EDFA main body is well known to those skilled in the art and is not described herein again;
the optical path structure for the gain slope real-time detection of the erbium-doped fiber amplifier in the embodiment of the present disclosure (hereinafter, referred to as the optical path structure) can be implemented in two ways:
one is to realize the real-time detection of the gain slope GT by adding related devices on the main optical path of the output end of the EDFA main body;
the other is that related devices are added on an auxiliary optical path at the output end of the EDFA main body to realize the real-time detection of the gain slope GT;
the first implementation includes the following embodiments:
embodiment one, as shown in fig. 3;
the optical path structure includes: a first filter 1, a second filter 2, a first photodiode 3, a second photodiode 4; the two photodiodes are used as optical power monitoring devices;
the common end of the first filter 1 is connected with the output end of the EDFA main body, and the reflection end of the first filter 1 is connected with the common end of the second filter 2; the transmission end of the first filter 1 is connected with the first photodiode 3, and the transmission end of the second filter 2 is connected with the second photodiode 4; the reflecting end of the second filter 2 is used as a new output end of the erbium-doped fiber amplifier;
the first filter 1 and the second filter 2 are both band-pass filters, and except their respective transmission wavelengths, the other wavelengths are their respective reflection wavelengths; the transmission wavelengths of the two filters 1 and 2 are respectively the out-of-band short wavelength and the out-of-band long wavelength of the signal wavelength of the EDFA main body; the transmission wavelength range takes the power monitoring precision of out-of-band ASE (spontaneous Emission noise) which is not influenced by the signal wavelength as a standard; in general, for a filter having a short wavelength outside a band in which a transmission wavelength of a signal of an EDFA main body is set, the shortest wavelength having a transmission center distant from the signal wavelength of the EDFA main body is 4nm to 5nm or more; for the filter with the transmission wavelength of the out-of-band long wavelength of the signal wavelength of the EDFA body, the transmission center of the filter is 4nm to 5nm above the longest wavelength of the signal wavelength of the EDFA body; the transmission wavelength bandwidth of the two filters can be generally selected from 1nm to 3 nm; the out-of-band short-wave spontaneous radiation noise and the out-of-band long-wave spontaneous radiation noise can be extracted through the two filters 1 and 2, and the power of the out-of-band short-wave spontaneous radiation noise and the power of the out-of-band long-wave spontaneous radiation noise are respectively detected through the two photodiodes 3 and 4;
the advantage of this structure is that the out-of-band ASE power is larger, but this results in a larger increase in the loss at the output of the erbium doped fiber amplifier.
Example two, as shown in fig. 4;
the optical path structure includes: a first filter 1, a second filter 2, a first photodiode 3, a second photodiode 4, a detection beam splitter 5; the two photodiodes are used as optical power monitoring devices;
the common end of the detection optical splitter 5 is connected with the output end of the EDFA main body, and the main output end of the detection optical splitter 5 is used as the new output end of the erbium-doped fiber amplifier; the auxiliary output end of the detection optical splitter 5 is connected with the common end of the first filter 1, and the reflection end of the first filter 1 is connected with the common end of the second filter 2; the transmission end of the first filter 1 is connected with the first photodiode 3, and the transmission end of the second filter 2 is connected with the second photodiode 4; the reflecting end of the second filter 2 is connected with the optical fiber wound by a small circle, or is connected with the attenuation loss of more than 20dB to completely leak out the redundant power, or the second filter 2 can be made into a 1 x 1 device, namely only a public end and a transmission end;
the first filter 1 and the second filter 2 are both band-pass filters, and except their respective transmission wavelengths, the other wavelengths are their respective reflection wavelengths; the transmission wavelengths of the two filters 1 and 2 are respectively the out-of-band short wavelength and the out-of-band long wavelength of the signal wavelength of the EDFA main body; the transmission wavelength range takes the power monitoring precision of out-of-band ASE (spontaneous Emission noise) which is not influenced by the signal wavelength as a standard; in general, for a filter having a short wavelength outside a band in which a transmission wavelength of a signal of an EDFA main body is set, the shortest wavelength having a transmission center distant from the signal wavelength of the EDFA main body is 4nm to 5nm or more; for the filter with the transmission wavelength of the out-of-band long wavelength of the signal wavelength of the EDFA body, the transmission center of the filter is 4nm to 5nm above the longest wavelength of the signal wavelength of the EDFA body; the transmission wavelength bandwidth of the two filters can be generally selected from 1nm to 3 nm; the out-of-band short-wave spontaneous radiation noise and the out-of-band long-wave spontaneous radiation noise can be extracted through the two filters 1 and 2, and the power of the out-of-band short-wave spontaneous radiation noise and the power of the out-of-band long-wave spontaneous radiation noise are respectively detected through the two photodiodes 3 and 4; the optimal value can be obtained by detecting the splitting ratio of the optical splitter 5 according to experiments or simulation, and the monitoring of the out-of-band ASE power is realized on the premise of small loss of the main optical path.
Example three, as shown in fig. 5;
the optical path structure includes: a first filter 1, a second filter 2, a first photodiode 3, a second photodiode 4, and a third filter 6; the two photodiodes are used as optical power monitoring devices;
the common end of the third filter 6 is connected with the output end of the EDFA main body, and the transmission end of the third filter 6 is used as the new output end of the erbium-doped fiber amplifier; the reflection end of the third filter 6 is connected with the common end of the first filter 1; the reflection end of the first filter 1 is connected with the common end of the second filter 2; the transmission end of the first filter 1 is connected with the first photodiode 3, and the transmission end of the second filter 2 is connected with the second photodiode 4; the reflecting end of the second filter 2 is connected with the optical fiber wound by a small circle, or is connected with the attenuation loss of more than 20dB to completely leak out the redundant power, or the second filter 2 can be made into a 1 x 1 device, namely only a public end and a transmission end;
wherein, the transmission wavelength of the third filter 6 is the in-band signal wavelength of the EDFA main body, and the other wavelengths are the reflection wavelengths thereof; the first filter 1 and the second filter 2 are both band-pass filters, and except for respective transmission wavelengths, other wavelengths are respective reflection wavelengths; the transmission wavelengths of the two filters 1 and 2 are respectively the out-of-band short wavelength and the out-of-band long wavelength of the signal wavelength of the EDFA main body; the transmission wavelength range takes the power monitoring precision of out-of-band ASE (Amplified spontaneous emission noise) which is not influenced by the signal wavelength as a standard; in general, for a filter having a short wavelength outside a band in which a transmission wavelength of a signal of an EDFA main body is set, the shortest wavelength having a transmission center distant from the signal wavelength of the EDFA main body is 4nm to 5nm or more; for the filter with the transmission wavelength of the out-of-band long wavelength of the signal wavelength of the EDFA body, the transmission center of the filter is 4nm to 5nm above the longest wavelength of the signal wavelength of the EDFA body; the transmission wavelength bandwidth of the two filters can be generally selected from 1nm to 3 nm; the two filters 1 and 2 can extract out-of-band short-wave spontaneous radiation noise and out-of-band long-wave spontaneous radiation noise, and the power of the out-of-band short-wave spontaneous radiation noise and the power of the out-of-band long-wave spontaneous radiation noise are respectively detected through the two photodiodes 3 and 4.
Example four, as shown in fig. 6;
in order to ensure that the transmission ends of the first filter 1 and the second filter 2 have the requirement on the isolation of signal wavelengths, which is usually greater than 60dB, the first filter 1 and the second filter 2 can both adopt a series structure of more than two filters; in fig. 6, the first filter 1 comprises filters 1-1 and 1-2 connected in series, and the second filter 2 comprises filters 2-1 and 2-2 connected in series;
the rest is the same as the first embodiment.
The second implementation includes the following embodiments:
example five, as shown in fig. 7;
the optical path structure includes: a first filter 1, a second filter 2, a first photodiode 3, a second photodiode 4, a detection beam splitter 5; the two photodiodes are used as optical power monitoring devices;
the common end of the detection optical splitter 5 is connected with the auxiliary output end of an output optical splitter 7 in the EDFA main body; the main output end of the detection optical splitter 5 is connected with a photodiode 8 in the EDFA main body, and the auxiliary output end of the detection optical splitter 5 is connected with the common end of the first filter 1; the reflection end of the first filter 1 is connected with the common end of the second filter 2; the transmission end of the first filter 1 is connected with the first photodiode 3, and the transmission end of the second filter 2 is connected with the second photodiode 4; the reflecting end of the second filter 2 is connected with the optical fiber wound by a small circle, or is connected with the attenuation loss of more than 20dB to completely leak out the redundant power, or the second filter 2 can be made into a 1 x 1 device, namely only a public end and a transmission end;
the first filter 1 and the second filter 2 are both band-pass filters, and except their respective transmission wavelengths, the other wavelengths are their respective reflection wavelengths; the transmission wavelengths of the two filters 1 and 2 are respectively the out-of-band short wavelength and the out-of-band long wavelength of the signal wavelength of the EDFA main body; the transmission wavelength range takes the power monitoring precision of out-of-band ASE (spontaneous Emission noise) which is not influenced by the signal wavelength as a standard; in general, for a filter having a short wavelength outside a band in which a transmission wavelength of a signal of an EDFA main body is set, the shortest wavelength having a transmission center distant from the signal wavelength of the EDFA main body is 4nm to 5nm or more; for the filter with the transmission wavelength of the out-of-band long wavelength of the signal wavelength of the EDFA body, the transmission center of the filter is 4nm to 5nm above the longest wavelength of the signal wavelength of the EDFA body; the transmission wavelength bandwidth of the two filters can be generally selected from 1nm to 3 nm; the out-of-band short-wave spontaneous radiation noise and the out-of-band long-wave spontaneous radiation noise can be extracted through the two filters 1 and 2, and the power of the out-of-band short-wave spontaneous radiation noise and the power of the out-of-band long-wave spontaneous radiation noise are respectively detected through the two photodiodes 3 and 4; the detection of the splitting ratio of the splitter 5 and the output splitter 7 in the EDFA main body can obtain the optimal value according to experiments or simulation, and the monitoring of the out-of-band ASE power is realized on the premise of small loss of a main optical path.
In the embodiment shown in fig. six, the transmission wavelength of the filters 1-1 and 1-2 is 1525nm, the bandwidth is 1nm, and the overall transmission isolation is greater than 70dB after the filters are connected in series; the transmission wavelength of the filter 2-1 and the transmission wavelength of the filter 2-2 are 1573nm, the bandwidth is 1nm, and the integral transmission isolation degree is larger than 70dB after the filters are connected in series; the simulation results of different gain gradients GT at signal wavelengths of 1529-1569 nm with a gain G of 25dB and at-10 dBm input are shown in the following table:
| In(dBm) | Gain(dB) | 1573ASE(dBm) | 1525ASE(dBm) | ASE_Delta(dB) | GT_simu(dB) |
| -10.00 | 25.02 | -22.19 | -28.25 | 6.06 | 2.92 |
| -10.00 | 24.97 | -22.53 | -27.79 | 5.27 | 1.95 |
| -10.00 | 25.00 | -22.79 | -27.24 | 4.44 | 0.92 |
| -10.00 | 25.03 | -23.03 | -26.71 | 3.68 | -0.09 |
| -10.00 | 24.98 | -23.24 | -26.30 | 3.06 | -1.01 |
| -10.00 | 25.00 | -23.39 | -25.81 | 2.42 | -1.97 |
| -10.00 | 25.01 | -23.49 | -25.34 | 1.84 | -2.91 |
obtaining a calibration relation according to values of the simulated gain slope GT _ simul (dB) and the out-of-band ASE power difference ASE _ Delta (dB), for example, obtaining a figure 8 by adopting quadratic fitting; wherein y is a x2+ b x + c, where y denotes GT _ simul (db), x denotes ASE _ delta (db), and a, b, c are fitting coefficients of a quadratic curve.
And (3) performing theoretical precision verification according to the simulation result of the ASE _ Delta (dB) and the obtained values of a, b and c, wherein the simulation result and the calculation theoretical result are shown in the following table:
| In(dBm) | Gain(dB) | 1573ASE(dBm) | 1525ASE(dBm) | ASE_Delta(dB) | GT_simu(dB) | GT_cacl(dB) | GT_Delta(dB) |
| -10.00 | 25.02 | -22.19 | -28.25 | 6.06 | 2.92 | 2.91 | -0.02 |
| -10.00 | 24.97 | -22.53 | -27.79 | 5.27 | 1.95 | 1.97 | 0.02 |
| -10.00 | 25.00 | -22.79 | -27.24 | 4.44 | 0.92 | 0.93 | 0.01 |
| -10.00 | 25.03 | -23.03 | -26.71 | 3.68 | -0.09 | -0.11 | -0.02 |
| -10.00 | 24.98 | -23.24 | -26.30 | 3.06 | -1.01 | -1.01 | -0.01 |
| -10.00 | 25.00 | -23.39 | -25.81 | 2.42 | -1.97 | -1.98 | -0.01 |
| -10.00 | 25.01 | -23.49 | -25.34 | 1.84 | -2.91 | -2.89 | 0.01 |
| -10.00 | 25.03 | -22.65 | -27.46 | 4.81 | 1.39 | 1.41 | 0.01 |
| -10.00 | 25.03 | -23.31 | -26.00 | 2.69 | -1.53 | -1.56 | -0.03 |
| -10.00 | 24.99 | -23.58 | -24.70 | 1.13 | -4.24 | -4.09 | 0.15 |
as can be seen from the table, based on the simulation result, the accuracy of GT _ cacl can be ensured within a certain range by calculating according to the quadratic fit curve, and the difference GT _ Delta with GT _ simul is about 0.15dB at most.
In an actual product, an actual value of ASE power at 1525nm and an actual value of ASE power at 1573nm are respectively obtained according to the first photodiode 3 and the second photodiode 4, an actual out-of-band ASE power difference ASE _ Delta is obtained through calculation, and an actual GT value corresponding to any actual ASE _ Delta, namely a real-time gain slope GT _ cacl, can be calculated according to actual calibration values of a, b and c.
The specific fitting mode can be determined according to actual data and actual conditions.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (10)
1. An optical path structure for gain slope real-time detection of an erbium-doped fiber amplifier, comprising: two filters, two optical power monitoring devices;
the two filters are used for respectively extracting out-of-band short-wave spontaneous radiation noise and out-of-band long-wave spontaneous radiation noise in the output of the EDFA main body; the two optical power monitoring devices are used for respectively detecting the out-of-band short-wave spontaneous emission noise power and the out-of-band long-wave spontaneous emission noise power.
2. The optical path structure for gain slope real-time detection of an erbium-doped fiber amplifier according to claim 1,
the two filters comprise a first filter and a second filter, and the two optical power monitoring devices comprise a first optical power monitoring device and a second optical power monitoring device;
the common end of the first filter is used for accessing the output of the EDFA body or one part of the output of the EDFA body; the reflection end of the first filter is connected with the common end of the second filter; the transmission end of the first filter is connected with the first optical power monitoring device, and the transmission end of the second filter is connected with the second optical power monitoring device;
and the transmission wavelength of one filter is the out-of-band short wavelength of the signal wavelength of the EDFA body, and the transmission wavelength of the other filter is the out-of-band long wavelength of the signal wavelength of the EDFA body.
3. The optical path structure for gain slope real-time detection of an erbium-doped fiber amplifier according to claim 2,
for the filter with the transmission wavelength of the short wavelength outside the band, the transmission center of the filter is 4nm to 5nm away from the shortest wavelength of the signal wavelength of the EDFA main body;
for the filter with the transmission wavelength of the out-of-band long wavelength of the signal wavelength of the EDFA body, the transmission center of the filter is 4nm to 5nm above the longest wavelength of the signal wavelength of the EDFA body;
the transmission wavelength bandwidths of the two filters are respectively 1 nm-3 nm.
4. The optical path structure for gain slope real-time detection of an erbium-doped fiber amplifier according to claim 2 or 3,
the common end of the first filter is connected with the output end of the EDFA main body; the reflecting end of the second filter is used as a new output end of the erbium-doped fiber amplifier;
the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
5. The optical path structure for real-time detection of gain slope of an erbium-doped fiber amplifier according to claim 2 or 3, further comprising a detection splitter;
the common end of the detection optical splitter is connected with the output end of the EDFA main body, and the main output end of the detection optical splitter is used as a new output end of the erbium-doped fiber amplifier; the auxiliary output end of the detection optical splitter is connected with the common end of the first filter;
the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
6. The optical path structure for gain slope real-time detection of an erbium doped fiber amplifier according to claim 5,
the second filter is provided with a reflection end, and the reflection end of the second filter is connected with the optical fiber wound by a small circle or connected with the attenuation loss of more than 20 dB; or the second filter is a 1 x 1 device, namely, only a public end and a transmission end.
7. The optical path structure for real-time detection of gain tilt of an erbium doped fiber amplifier according to claim 2 or 3, further comprising a third filter;
the common end of the third filter is connected with the output end of the EDFA main body, and the transmission end of the third filter is used as the new output end of the erbium-doped fiber amplifier; the reflection end of the third filter is connected with the common end of the first filter;
the transmission wavelength of the third filter is the in-band signal wavelength of the EDFA main body, and other wavelengths are the reflection wavelengths of the EDFA main body; the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
8. The optical path structure for gain slope real-time detection of an erbium doped fiber amplifier according to claim 7,
the second filter is provided with a reflection end, and the reflection end of the second filter is connected with the optical fiber wound by a small circle or connected with the attenuation loss of more than 20 dB; or the second filter is a 1 x 1 device, namely, only a public end and a transmission end.
9. The optical path structure for real-time detection of gain slope of an erbium-doped fiber amplifier according to claim 2 or 3, further comprising a detection splitter;
the common end of the detection optical splitter is connected with the auxiliary output end of the output optical splitter in the EDFA main body; the main output end of the detection optical splitter is connected with an output end optical power monitoring device in the EDFA main body, and the auxiliary output end of the detection optical splitter is connected with the common end of the first filter;
the first filter and the second filter are both band-pass filters, and except for the respective transmission wavelengths, the other wavelengths are the respective reflection wavelengths.
10. A method for detecting gain slope of an erbium-doped fiber amplifier in real time is characterized by comprising the following steps:
defining the difference value of the out-of-band short-wave spontaneous emission noise power and the out-of-band long-wave spontaneous emission noise power as an out-of-band ASE power difference;
and fitting to obtain a calibration relation between the out-of-band ASE power difference and the gain slope, calculating to obtain a real-time out-of-band ASE power difference through detecting the out-of-band short-wave spontaneous emission noise power and the out-of-band long-wave spontaneous emission noise power of the EDFA main body in real time, and obtaining the real-time gain slope according to the calibration relation between the out-of-band ASE power difference and the gain slope obtained through fitting.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112505412A (en) * | 2020-10-30 | 2021-03-16 | 北京空间飞行器总体设计部 | Method for processing satellite signal out-of-band redundant radiation spectrum density test data |
| CN114156722A (en) * | 2021-12-15 | 2022-03-08 | 无锡市德科立光电子技术股份有限公司 | VOA control method in variable gain erbium-doped fiber amplifier |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112505412A (en) * | 2020-10-30 | 2021-03-16 | 北京空间飞行器总体设计部 | Method for processing satellite signal out-of-band redundant radiation spectrum density test data |
| CN112505412B (en) * | 2020-10-30 | 2023-03-31 | 北京空间飞行器总体设计部 | Method for processing satellite signal out-of-band redundant radiation spectrum density test data |
| CN114156722A (en) * | 2021-12-15 | 2022-03-08 | 无锡市德科立光电子技术股份有限公司 | VOA control method in variable gain erbium-doped fiber amplifier |
| CN114156722B (en) * | 2021-12-15 | 2023-12-22 | 无锡市德科立光电子技术股份有限公司 | Control method of VOA in variable gain erbium-doped fiber amplifier |
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