LP-Band erbium-doped optical fiber amplifier based on circulator

Abstract

The utility model discloses an LP-Band erbium-doped optical fiber amplifier based on a circulator, which relates to the technical field of optical fiber amplifiers and comprises an input gain module, the circulator, an intermediate gain module, a reflector and an output module. The input gain module is connected with the input end of the circulator, the common end of the circulator is connected with the reflector through the middle gain module, and the output module is connected with the output end of the circulator. The input gain module is used for amplifying an input optical signal and transmitting the input optical signal to the input end of the circulator, the optical signal amplified by the input gain module is input to the intermediate gain module through the common end of the circulator, and the optical signal is amplified by the intermediate gain module and then input to the reflector; the reflector is used for reflecting the received optical signal back to the intermediate gain module, and the optical signal reflected by the reflector is amplified by the intermediate gain module and then is output to the output module through the circulator. According to the invention, the gain efficiency of the erbium-doped optical fiber amplifier working in the LP-Band can be improved.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic amplifier technology, and in particular to an LP-Band erbium-doped fiber optic amplifier based on a circulator. Background Technology

[0002] To fully exploit the upper limit of optical communication network bandwidth, wavelength division multiplexing (WDM) has become the preferred solution and research hotspot in the field of optical fiber communication due to its lower deployment cost and higher transmission capacity. This includes erbium-doped optical fiber amplifiers (EDFAs). However, the wider wavelength bandwidth places higher demands on other components of the system.

[0003] For erbium-doped fiber amplifiers operating in the C-band (1524nm-1572nm), the application range has become saturated and can no longer meet the requirements. Erbium-doped fiber amplifiers operating in the long-wavelength LP-band (1575nm-1626nm) have gradually attracted widespread attention because they can effectively increase communication bandwidth.

[0004] However, compared to EDFAs operating in the C-band, the gain efficiency of EDFAs currently operating in the LP-band is not ideal, requiring longer erbium-doped fibers, and the noise figure performance is poor, making it difficult to meet the needs of practical applications. Utility Model Content

[0005] In response to the aforementioned problems and technical requirements, the applicant has proposed an LP-Band erbium-doped fiber amplifier based on a circulator.

[0006] The technical solution of this utility model is as follows:

[0007] A circulator-based LP-Band erbium-doped fiber amplifier includes an input gain module, a circulator, an intermediate gain module, a reflector, and an output module.

[0008] The input gain module is connected to the input terminal of the circulator, the common terminal of the circulator is connected to the reflector through the intermediate gain module, and the output module is connected to the output terminal of the circulator.

[0009] The input gain module amplifies the input optical signal and transmits it to the input end of the circulator. The optical signal amplified by the input gain module is input to the intermediate gain module through the common end of the circulator, and then amplified by the intermediate gain module before being input to the reflector. The reflector reflects the received optical signal back to the intermediate gain module. The optical signal reflected by the reflector is amplified by the intermediate gain module and transmitted to the common end of the circulator, and then output to the output module through the output end of the circulator.

[0010] A further technical solution is that the input gain module includes an input port, a first wavelength division multiplexer, a first erbium-doped fiber, and a first pump source, wherein...

[0011] The first input terminal of the first wavelength division multiplexer is connected to the input port, the second input terminal of the first wavelength division multiplexer is connected to the first pump source, and the common terminal of the first wavelength division multiplexer is connected to one end of the first erbium-doped optical fiber.

[0012] A further technical solution is that the input gain module further includes a second wavelength division multiplexer, a second erbium-doped fiber, and a second pump source, wherein,

[0013] The first input terminal of the second wavelength division multiplexer is connected to the other end of the first erbium-doped fiber, the second input terminal of the second wavelength division multiplexer is connected to the second pump source, and the common terminal of the second wavelength division multiplexer is connected to one end of the second erbium-doped fiber.

[0014] A further technical solution is that the input gain module further includes an IGFF, the input end of which is connected to the other end of the second erbium-doped fiber, and the output end of which is connected to the input end of the circulator.

[0015] A further technical solution is that the intermediate gain module includes a third wavelength division multiplexer, a third erbium-doped fiber, a third pump source, a fourth wavelength division multiplexer, a fourth pump source, and a third beam splitter, wherein...

[0016] The first input terminal of the third wavelength division multiplexer is connected to the common terminal of the circulator. The second input terminal of the third wavelength division multiplexer is connected to the third pump source. The common terminal of the third wavelength division multiplexer is connected to the common terminal of the fourth wavelength division multiplexer through the third erbium-doped fiber. The second input terminal of the fourth wavelength division multiplexer is connected to the first splitting terminal of the third beam splitter. The input terminal of the third beam splitter is connected to the fourth pump source.

[0017] A further technical solution is that the intermediate gain module also includes a GFF, a fifth wavelength division multiplexer, a sixth wavelength division multiplexer, a fourth erbium-doped fiber, and a fifth pump source, wherein...

[0018] The input terminal of the GFF is connected to the first input terminal of the fourth wavelength division multiplexer, the output terminal of the GFF is connected to the first input terminal of the fifth wavelength division multiplexer, the second input terminal of the fifth wavelength division multiplexer is connected to the second splitting terminal of the third optical splitter, the common terminal of the fifth wavelength division multiplexer is connected to the common terminal of the sixth wavelength division multiplexer through the fourth erbium-doped fiber, and the second input terminal of the sixth wavelength division multiplexer is connected to the fifth pump source.

[0019] A further technical solution is that the center wavelength of the first pump source, the second pump source, the third pump source, the fourth pump source and the fifth pump source is 980nm.

[0020] A further technical solution is that the intermediate gain module further includes a first beam splitter, a first photodetector, a variable attenuator, a second beam splitter, and a second photodetector, wherein...

[0021] The input terminal of the first beam splitter is connected to the first input terminal of the sixth wavelength division multiplexer, the first beam splitting terminal of the first beam splitter is connected to the input terminal of the variable attenuator, and the second beam splitting terminal of the first beam splitter is connected to the detection terminal of the first photodetector.

[0022] The output of the variable attenuator is connected to the input of the second beam splitter, the first beam splitter is connected to the reflector, and the second beam splitter is connected to the detection end of the second photodetector.

[0023] A further technical solution is that the splitting ratio of the first splitting end to the second splitting end of the first and second splitting ends is 99:1; and the splitting ratio of the first splitting end to the second splitting end of the third splitting end is 49:51.

[0024] A further technical solution is that the output module includes a filter and an output port;

[0025] The output of the circulator is connected to the input of the filter, and the output of the filter is connected to the output port.

[0026] The beneficial technical effects of this utility model are:

[0027] This invention utilizes a circulator and a reflector to enable the signal light to achieve secondary gain in the third and fourth erbium-doped fibers within the intermediate gain module. This fully utilizes the erbium-doped fiber, reduces its overall length, lowers the pump source power, and improves the gain efficiency of the erbium-doped fiber amplifier operating in the LP-band. This provides a possibility for the miniaturization and integration of erbium-doped fiber amplifiers operating in the LP-band. Furthermore, the erbium-doped fiber amplifier provided by this invention can also reduce noise, especially at lower gains, thus improving the overall performance of the erbium-doped fiber amplifier. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of one embodiment of the LP-Band erbium-doped fiber amplifier based on a circulator provided by this utility model.

[0029] Figure 2This is a comparison chart of the noise curves of the LP-Band erbium-doped fiber amplifier based on a circulator provided by this utility model and a conventional erbium-doped fiber amplifier.

[0030] Reference numerals: 1-Input port, 2-First wavelength division multiplexer, 3-First erbium-doped fiber, 4-Second wavelength division multiplexer, 5-Second erbium-doped fiber, 6-IGFF isolator, 7-Circulator, 8-Third wavelength division multiplexer, 9-Third erbium-doped fiber, 10-Fourth wavelength division multiplexer, 11-GFF, 12-Fifth wavelength division multiplexer, 13-Fourth erbium-doped fiber, 14-Sixth wavelength division multiplexer, 15-First beam splitter, 16-Variable attenuator, 17-Second beam splitter, 18-Reflector, 19-First pump source, 20-Second pump source, 21-Filter, 22-Output port, 23-Third pump source, 24-Fourth pump source, 25-Third beam splitter, 26-Fifth pump source, 27-First photodetector, 28-Second photodetector. Detailed Implementation

[0031] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0032] This invention provides a circulator-based LP-Band erbium-doped fiber amplifier, comprising an input gain module, a circulator 7, an intermediate gain module, a reflector 18, and an output module.

[0033] The input gain module is connected to the input terminal of the circulator 7, the common terminal of the circulator 7 is connected to the reflector 18 through the intermediate gain module, and the output module is connected to the output terminal of the circulator 7.

[0034] The input gain module amplifies the input optical signal and transmits it to the input terminal of the circulator 7. The optical signal amplified by the input gain module is input to the intermediate gain module through the common terminal of the circulator 7, and then amplified by the intermediate gain module before being input to the reflector 18. The reflector 18 reflects the received optical signal back to the intermediate gain module. The optical signal reflected by the reflector is amplified by the intermediate gain module and transmitted to the common terminal of the circulator 7, and then output to the output module through the output terminal of the circulator 7.

[0035] The aforementioned LP-Band erbium-doped fiber amplifier specifically refers to an erbium-doped fiber amplifier operating in the long-wavelength band, i.e., LP-band. The input signal light is input through the input gain module, initially amplified, and then transmitted to the intermediate gain module. A secondary gain structure is formed using circulator 7, the intermediate gain module, and reflector 18. The optical signal input from the intermediate gain module to reflector 18 returns to circulator 7 through the original optical path, allowing the intermediate gain module to perform secondary gain on the optical signal. Finally, the amplified optical signal is output by the output module. This invention fully utilizes erbium-doped fiber, reduces the total length of the erbium-doped fiber, lowers the pump source power, and improves the gain efficiency of the erbium-doped fiber amplifier operating in the LP-band. The form of circulator 7 and reflector 18 can be consistent with existing technologies. The specific structures of the input gain module, intermediate gain module, and output module are described below.

[0036] Figure 1 The diagram shown is a schematic representation of one embodiment of the erbium-doped fiber amplifier provided by this utility model. Figure 1 As shown, the input gain module includes an input port 1, a first wavelength division multiplexer (WDM) 2, a first erbium-doped fiber 3, a first pump source 19, a second wavelength division multiplexer 4, a second erbium-doped fiber 5, and a second pump source 20, wherein...

[0037] The first input terminal of the first wavelength division multiplexer 2 is connected to the input port, the second input terminal of the first wavelength division multiplexer 2 is connected to the first pump source, and the common terminal of the first wavelength division multiplexer 2 is connected to one end of the first erbium-doped fiber 3. The first input terminal of the second wavelength division multiplexer 4 is connected to the other end of the first erbium-doped fiber 3, the second input terminal of the second wavelength division multiplexer 4 is connected to the second pump source 20, and the common terminal of the second wavelength division multiplexer 4 is connected to one end of the second erbium-doped fiber 5.

[0038] In this embodiment, the input gain module performs two-stage amplification of the input optical signal. Specifically, the first pump source 19 injects pump light into the first erbium-doped fiber 3 through the first wavelength division multiplexer 2, performing a first-stage amplification of the optical signal. The second pump source 20 injects pump light into the second erbium-doped fiber 5 through the second wavelength division multiplexer 4, performing a second-stage amplification of the optical signal.

[0039] Furthermore, the input gain module also includes an IGFF 6 (Isolator and Gain Flattening Filter), the input end of which is connected to the other end of the second erbium-doped fiber, and the output end of which is connected to the input end of the circulator 7.

[0040] The IGFF 6 is an integrated device that combines the functions of an optical isolator and a gain flattening filter in the same package. It can isolate reverse signals and flatten the gain to improve the overall performance and reliability of the fiber amplifier. The model of the IGFF6 can be selected according to actual needs.

[0041] Further, the intermediate gain module includes a third wavelength division multiplexer 8, a third erbium-doped fiber 9, a third pump source 23, a fourth wavelength division multiplexer 10, a fourth pump source 24, a third beam splitter 25, a GFF (Gain Flattening Filter) 11, a fifth wavelength division multiplexer 12, a sixth wavelength division multiplexer 14, a fourth erbium-doped fiber 13, and a fifth pump source 26. The first input terminal of the third wavelength division multiplexer 8 is connected to the common terminal of the circulator 7. The second input terminal of the third wavelength division multiplexer 8 is connected to the third pump source 23. The common terminal of the third wavelength division multiplexer 8 is connected to the common terminal of the fourth wavelength division multiplexer 10 via the third erbium-doped fiber 9. The second input terminal of the fourth wavelength division multiplexer 10 is connected to the first beam splitter of the third beam splitter 25. The input terminal of the third beam splitter 25 is connected to the fourth pump source 24. The input terminal of the GFF 11 is connected to the first input terminal of the fourth wavelength division multiplexer 10, the output terminal of the GFF 11 is connected to the first input terminal of the fifth wavelength division multiplexer 12, the second input terminal of the fifth wavelength division multiplexer 12 is connected to the second splitting terminal of the third beam splitter 25, the common terminal of the fifth wavelength division multiplexer 12 is connected to the common terminal of the sixth wavelength division multiplexer 14 through the fourth erbium-doped fiber 13, and the second input terminal of the sixth wavelength division multiplexer 14 is connected to the fifth pump source 26.

[0042] As described above, the intermediate gain module performs secondary gain on the optical signal amplified by the input gain module. In this embodiment, the intermediate gain module utilizes the third erbium-doped fiber 9 and the fourth erbium-doped fiber 13 to perform secondary amplification of the optical signal for each gain operation. Specifically, when the intermediate gain module performs the first gain on the optical signal amplified by the input gain module, the third pump source 23 injects pump light into the third erbium-doped fiber 9 through the third wavelength division multiplexer 8 to perform primary amplification of the optical signal amplified by the input gain module. The fourth pump source 24 injects pump light into the fourth erbium-doped fiber 13 through the third beam splitter 25 and the fifth wavelength division multiplexer 12 to perform secondary amplification of the optical signal amplified by the input gain module.

[0043] The optical signal, after its first gain by the intermediate gain module, is reflected back to the intermediate gain module via the reflector along the original optical path. The intermediate gain module then performs a second gain. At this time, the fifth pump source 26 injects pump light into the fourth erbium-doped fiber 13 through the sixth wavelength division multiplexer 14, performing a first-stage amplification on the optical signal reflected back to the intermediate gain module. The fourth pump source 24 injects pump light into the third erbium-doped fiber 9 through the third beam splitter 25 and the fourth wavelength division multiplexer 10, performing a second-stage amplification on the optical signal reflected back to the intermediate gain module. The GFF 11 is used to equalize the optical signal gain and reduce the noise of the fiber amplifier. In this embodiment, the center wavelengths of the first pump source 19, the second pump source 20, the third pump source 23, the fourth pump source 24, and the fifth pump source 26 are all 980nm. The splitting ratio between the first and second beam splitters of the third beam splitter 25 is 49:51.

[0044] Furthermore, the intermediate gain module also includes a first beam splitter 15, a first photodetector 27, a variable attenuator 16, a second beam splitter 17, and a second photodetector 28, wherein,

[0045] The input terminal of the first beam splitter 15 is connected to the first input terminal of the sixth wavelength division multiplexer 14, the first beam splitter 15 is connected to the input terminal of the variable attenuator 16, and the second beam splitter 15 is connected to the detection terminal of the first photodetector 27.

[0046] The output of the variable attenuator 16 is connected to the input of the second beam splitter 17, the first beam splitter of the second beam splitter 17 is connected to the reflector 18, and the second beam splitter of the second beam splitter 17 is connected to the detection end of the second photodetector 28.

[0047] Specifically, the splitting ratio of the first splitter 15 to the second splitter 17 is 99:1. The first photodetector 27 is used to detect the optical power of the optical signal input to the variable attenuator 16, and the second photodetector 28 is used to detect the optical power of the optical signal output from the variable attenuator 16. The variable attenuator 16 is used to adjust the optical power of the optical signal to meet different application needs.

[0048] Furthermore, the output module includes a filter 21 and an output port 22; the output terminal of the circulator 7 is connected to the input terminal of the filter 21, and the output terminal of the filter 21 is connected to the output port 22. The filter 21 is used to further filter out noise from the output optical signal.

[0049] This application compares the noise of the provided circulator-based LP-Band erbium-doped fiber amplifier with that of a conventional erbium-doped fiber amplifier at both high gain (31dB) and low gain (21dB) levels. Since conventional erbium-doped fiber amplifiers cannot reuse the same erbium-doped fiber, the conventional erbium-doped fiber amplifier used in the comparison requires six segments of erbium-doped fiber and six pump sources. This achieves the same gain as this application while maintaining the same total equivalent erbium-doped fiber length and pump source power. In other words, the erbium-doped fiber amplifier provided in this application effectively improves the utilization rate of erbium-doped fiber and reduces the number of pump sources required. Figure 2 The comparison results show that, at the same gain, the noise of the circulator-based LP-Band erbium-doped fiber amplifier provided in this application is less than that of a conventional erbium-doped fiber amplifier, and the noise reduction effect is more obvious at lower gains.

[0050] It should be noted that, Figure 2 In this context, "ring-based lower / higher gain" refers to the noise curves of the circulator-based LP-Band erbium-doped fiber amplifier provided in this application at 21dB / 31dB; "conventional lower / higher gain" refers to the noise curves of the conventional erbium-doped fiber amplifier at 21dB / 31dB.

[0051] The above descriptions are merely preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A circulator-based LP-Band erbium-doped fiber amplifier, characterized in that, It includes an input gain module, a circulator, an intermediate gain module, a reflector, and an output module, among which, The input gain module is connected to the input terminal of the circulator, the common terminal of the circulator is connected to the reflector through the intermediate gain module, and the output module is connected to the output terminal of the circulator. The input gain module amplifies the input optical signal and transmits it to the input end of the circulator. The optical signal amplified by the input gain module is input to the intermediate gain module through the common end of the circulator, and then amplified by the intermediate gain module before being input to the reflector. The reflector reflects the received optical signal back to the intermediate gain module. The optical signal reflected by the reflector is amplified by the intermediate gain module and transmitted to the common end of the circulator, and then output to the output module through the output end of the circulator.

2. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 1, characterized in that, The input gain module includes an input port, a first wavelength division multiplexer, a first erbium-doped fiber, and a first pump source, wherein... The first input terminal of the first wavelength division multiplexer is connected to the input port, the second input terminal of the first wavelength division multiplexer is connected to the first pump source, and the common terminal of the first wavelength division multiplexer is connected to one end of the first erbium-doped optical fiber.

3. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 2, characterized in that, The input gain module further includes a second wavelength division multiplexer, a second erbium-doped fiber, and a second pump source, wherein... The first input terminal of the second wavelength division multiplexer is connected to the other end of the first erbium-doped fiber, the second input terminal of the second wavelength division multiplexer is connected to the second pump source, and the common terminal of the second wavelength division multiplexer is connected to one end of the second erbium-doped fiber.

4. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 2, characterized in that, The input gain module also includes an IGFF, the input of which is connected to the other end of the second erbium-doped fiber, and the output of which is connected to the input of the circulator.

5. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 3, characterized in that, The intermediate gain module includes a third wavelength division multiplexer, a third erbium-doped fiber, a third pump source, a fourth wavelength division multiplexer, a fourth pump source, and a third beam splitter, wherein... The first input terminal of the third wavelength division multiplexer is connected to the common terminal of the circulator. The second input terminal of the third wavelength division multiplexer is connected to the third pump source. The common terminal of the third wavelength division multiplexer is connected to the common terminal of the fourth wavelength division multiplexer through the third erbium-doped fiber. The second input terminal of the fourth wavelength division multiplexer is connected to the first splitting terminal of the third beam splitter. The input terminal of the third beam splitter is connected to the fourth pump source.

6. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 5, characterized in that, The intermediate gain module also includes a GFF, a fifth wavelength division multiplexer, a sixth wavelength division multiplexer, a fourth erbium-doped fiber, and a fifth pump source, wherein... The input terminal of the GFF is connected to the first input terminal of the fourth wavelength division multiplexer, the output terminal of the GFF is connected to the first input terminal of the fifth wavelength division multiplexer, the second input terminal of the fifth wavelength division multiplexer is connected to the second splitting terminal of the third optical splitter, the common terminal of the fifth wavelength division multiplexer is connected to the common terminal of the sixth wavelength division multiplexer through the fourth erbium-doped fiber, and the second input terminal of the sixth wavelength division multiplexer is connected to the fifth pump source.

7. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 6, characterized in that, The center wavelengths of the first, second, third, fourth, and fifth pump sources are 980 nm.

8. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 6, characterized in that, The intermediate gain module further includes a first beam splitter, a first photodetector, a variable attenuator, a second beam splitter, and a second photodetector, wherein... The input terminal of the first beam splitter is connected to the first input terminal of the sixth wavelength division multiplexer, the first beam splitting terminal of the first beam splitter is connected to the input terminal of the variable attenuator, and the second beam splitting terminal of the first beam splitter is connected to the detection terminal of the first photodetector. The output of the variable attenuator is connected to the input of the second beam splitter, the first beam splitter is connected to the reflector, and the second beam splitter is connected to the detection end of the second photodetector.

9. The circulator-based LP-Band erbium-doped fiber amplifier according to claim 8, characterized in that, The splitting ratio between the first and second splitting ends of the first and second splitters is 99:1; the splitting ratio between the first and second splitting ends of the third splitter is 49:

51.

10. The circulator-based LP-Band erbium-doped fiber amplifier according to any one of claims 1-9, characterized in that, The output module includes a filter and an output port; The output of the circulator is connected to the input of the filter, and the output of the filter is connected to the output port.

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