Erbium-doped fiber amplifier and optical communication system

Abstract

The utility model relates to the field of optical communication technology, and specifically to an erbium-doped fiber amplifier and an optical communication system. The erbium-doped fiber amplifier includes a pump unit and an input end, a reflection unit, a wavelength division multiplexer, an erbium-doped fiber and an output end which are arranged in sequence. The pump unit is used to provide pump light and input it to the wavelength division multiplexer, wherein an external optical signal is transmitted to the wavelength division multiplexer through the input end and the reflection unit in sequence, and the wavelength division multiplexer combines the optical signal transmitted by the reflection unit with the pump light and transmits it to the erbium-doped fiber for amplification, and the amplified forward optical signal is output through the output end, and the reverse spontaneous radiation optical signal generated by the erbium-doped fiber is transmitted to the reflection unit, and the reflection unit reflects the optical signal of a specific wavelength and returns it to the erbium-doped fiber via the wavelength division multiplexer. The application effectively reduces the optical power of the reverse spontaneous radiation optical signal of the overall erbium-doped fiber amplifier, and at the same time, reduces energy waste and improves the conversion efficiency of the signal light.

Description

Technical Field

[0001] The utility model relates to the technical field of optical communication, in particular to an erbium-doped optical fiber amplifier and an optical communication system. Background Art

[0002] As a type of optical amplifier, erbium-doped fiber amplifiers are widely used in optical communication systems, such as as relay amplifiers in long-distance communication systems, as power boosting amplifiers in the back stage of optical transmitters and preamplifiers in the front stage of optical receivers in optical communication systems, as broadband amplifiers in high-speed, large-capacity, multi-channel optical communication systems, and as soliton energy compensation amplifiers in high-speed, long-distance optical fiber soliton communication systems.

[0003] In the related art, for erbium-doped fiber amplifiers that amplify L-band or L++-band optical signals, due to the low amplification efficiency of the erbium-doped fiber amplifier for L-band or L++-band optical signals and the long length of the erbium-doped fiber, the optical power of the reverse ASE (Amplified Spontaneous Emission) optical signal of the erbium-doped fiber amplifier is greater than that of other conventional erbium-doped fiber amplifiers. Especially under extreme conditions such as no output light and a large pump light power, the optical power of the reverse ASE optical signal is large and cannot meet the requirements. Utility Model Content

[0004] The technical problem to be solved by the embodiments of the utility model is to provide an erbium-doped fiber amplifier and an optical communication system to solve the problem of high optical power of reverse spontaneous radiation optical signals of erbium-doped fiber amplifiers in the prior art.

[0005] The utility model discloses an erbium-doped fiber amplifier, comprising a pump unit and an input end, a reflection unit, a wavelength division multiplexer, an erbium-doped fiber and an output end which are arranged in sequence, wherein the pump unit is used to provide pump light and input it into the wavelength division multiplexer, wherein an external optical signal is transmitted to the wavelength division multiplexer via the input end and the reflection unit in sequence, the wavelength division multiplexer combines the optical signal transmitted by the reflection unit with the pump light and then transmits the combined optical signal to the erbium-doped fiber for amplification, the amplified forward optical signal is output via the output end, the reverse spontaneous radiation optical signal generated by the erbium-doped fiber is transmitted to the reflection unit, the reflection unit reflects the optical signal of a specific wavelength and returns to the erbium-doped fiber via the wavelength division multiplexer.

[0006] Optionally, the reflection unit comprises a fiber Bragg grating, and the fiber Bragg grating is arranged between the input end and the wavelength division multiplexer.

[0007] Optionally, the erbium-doped fiber amplifier further comprises a first optical isolator for isolating a reverse optical signal, wherein the first optical isolator is arranged between the input end and the fiber Bragg grating, and the optical signal input from the input end is transmitted to the fiber Bragg grating via the first optical isolator.

[0008] Optionally, the erbium-doped fiber amplifier also includes a first splitter and an input optical power monitoring unit, wherein the first splitter is arranged between the input end and the first optical isolator, the first splitter is used to split the input optical signal to the input optical power monitoring unit, and the input optical power monitoring unit is used to perform auxiliary monitoring of the optical power of the input optical signal.

[0009] Optionally, the input optical power monitoring unit includes a first photodiode, configured to receive the optical signal split by the first optical splitter.

[0010] Optionally, the erbium-doped fiber amplifier further comprises a second optical isolator for isolating a reverse optical signal, the second optical isolator being arranged between the output end and the erbium-doped fiber, and the forward optical signal output by the erbium-doped fiber is transmitted to the output end via the second optical isolator.

[0011] Optionally, the erbium-doped fiber amplifier also includes a second splitter and an output optical power monitoring unit, the second splitter is arranged between the second optical isolator and the output end, the second splitter is used to split the output forward optical signal to the output optical power monitoring unit, and the output optical power monitoring unit is used to assist in monitoring the optical power of the output forward optical signal.

[0012] Optionally, the input optical power monitoring unit includes a second photodiode, configured to receive the forward optical signal split by the second optical splitter.

[0013] Optionally, the reflection unit comprises a reflection plate, wherein the reflection plate is arranged between the input end and the wavelength division multiplexer, and a reflection film is arranged on a side of the reflection plate facing the wavelength division multiplexer.

[0014] The utility model also discloses an optical communication system, comprising a light source, a light receiving device and the erbium-doped fiber amplifier as described above, wherein the input end of the erbium-doped fiber amplifier receives the light signal of the light source, and the output end transmits the amplified forward light signal to the light receiving device.

[0015] Compared with the prior art, the beneficial effect of the erbium-doped fiber amplifier provided by the embodiment of the utility model is that: the present application sets a pump unit and an input end, a reflection unit, a wavelength division multiplexer, an erbium-doped fiber and an output end in sequence, the pump unit provides pump light and inputs it to the wavelength division multiplexer, the external optical signal is transmitted to the wavelength division multiplexer via the input end and the reflection unit in sequence, the wavelength division multiplexer combines the optical signal transmitted by the reflection unit with the pump light and transmits it to the erbium-doped fiber for amplification, the amplified forward optical signal is output via the output end, the setting of the reflection unit can reflect the optical signal of a specific wavelength in the reverse spontaneous radiation optical signal generated by the erbium-doped fiber, and return it to the erbium-doped fiber via the wavelength division multiplexer, thereby effectively reducing the optical power of the reverse spontaneous radiation optical signal of the overall erbium-doped fiber amplifier, and at the same time, reducing energy waste and greatly improving the conversion efficiency of the signal light. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 It is a structural schematic diagram of an erbium-doped fiber amplifier provided in an embodiment of the utility model;

[0018] Figure 2 It is a structural block diagram of an optical communication system provided by an embodiment of the utility model.

[0019] The reference numerals in the figures are:

[0020] 1. Erbium-doped fiber amplifier;

[0021] 10. Input end; 20. Reflection unit; 21. Fiber Bragg grating; 30. Wavelength division multiplexer; 40. Erbium-doped fiber; 50. Output end; 60. Pump unit; 70. First optical isolator; 80. First optical splitter; 90. Input optical power monitoring unit; 91. First photodiode; 100. Second optical isolator; 110. Second optical splitter; 120. Output optical power monitoring unit; 121. Second photodiode;

[0022] 2. Light source; 3. Light receiving device. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, a preferred embodiment of the present utility model is described in detail.

[0024] The utility model embodiment provides an erbium-doped fiber amplifier 1, such as Figure 1As shown, the erbium-doped fiber amplifier 1 includes a pump unit 60 and an input end 10, a reflection unit 20, a wavelength division multiplexer 30, an erbium-doped fiber 40 and an output end 50 which are arranged in sequence. The pump unit 60 is used to provide pump light and input it to the wavelength division multiplexer 30, wherein the external optical signal is transmitted to the wavelength division multiplexer 30 via the input end 10 and the reflection unit 20 in sequence, the wavelength division multiplexer 30 combines the optical signal transmitted by the reflection unit 20 with the pump light and transmits the combined optical signal to the erbium-doped fiber 40 for amplification, the amplified forward optical signal is output via the output end 50, the reverse spontaneous radiation optical signal generated by the erbium-doped fiber 40 is transmitted to the reflection unit 20, the reflection unit 20 reflects the optical signal of a specific wavelength and returns to the erbium-doped fiber 40 via the wavelength division multiplexer 30.

[0025] The present application sets a pump unit 60 and an input end 10, a reflection unit 20, a wavelength division multiplexer 30, an erbium-doped fiber 40 and an output end 50 in sequence. The pump unit 60 provides pump light and inputs it to the wavelength division multiplexer 30. The external optical signal is transmitted to the wavelength division multiplexer 30 via the input end 10 and the reflection unit 20 in sequence. The wavelength division multiplexer 30 combines the optical signal transmitted by the reflection unit 20 with the pump light and transmits the combined optical signal to the erbium-doped fiber 40 for amplification. The amplified forward optical signal is output via the output end 50. The setting of the reflection unit 20 can reflect the optical signal of a specific wavelength in the reverse spontaneous radiation optical signal generated by the erbium-doped fiber 40 and return it to the erbium-doped fiber 40 via the wavelength division multiplexer 30, thereby effectively reducing the optical power of the reverse spontaneous radiation optical signal of the overall erbium-doped fiber amplifier 1. At the same time, it reduces energy waste, improves the conversion efficiency of the signal light, and improves noise performance.

[0026] The optical signal inputted by the input terminal 10 is an optical signal of the L band or the L++ band. An optical signal of the L band generally refers to an optical signal with a wavelength range of 1570 nanometers to 1611 nanometers. An optical signal of the L++ band generally refers to an optical signal with a wavelength range of 1575 nanometers to 1626 nanometers.

[0027] The wavelength division multiplexer 30 is a device for coupling and combining two or more optical carrier signals of different wavelengths and coupling them into the same optical fiber for transmission. The wavelength division multiplexer 30 can combine the optical signal transmitted by the reflection unit 20 with the pump light and then couple them to the erbium-doped optical fiber 40 for transmission.

[0028] The erbium-doped fiber 40 is an optical fiber doped with erbium. Erbium is a rare earth element with special optical properties that can be used to amplify optical signals. When erbium ions are excited by external pump light, stimulated radiation occurs, thereby amplifying the optical signal passing through the optical fiber.

[0029] The pump unit 60 provides pump light for activating erbium-doped ions in the erbium-doped fiber amplifier 1 to amplify the optical signal. The pump unit 60 specifically uses a laser diode, and other input forms of pump light sources 2 can also be used. The laser diode can provide energy to excite the erbium ions in the erbium-doped fiber 40.

[0030] Optical fiber can be used to connect the input end 10 and the reflection unit 20, and the reflection unit 20 and the wavelength division multiplexer 30. Optical fiber is used as a transmission medium for optical signals. Optical fiber has extremely high bandwidth and can transmit optical signals of multiple channels at the same time, supporting high-speed data transmission and broadband communication requirements, with fast transmission speed and low signal transmission delay.

[0031] The optical signal of specific wavelength reflected by the reflection unit 20 can be an optical signal of a wavelength in the reverse spontaneous radiation optical signal, and in particular, can be an optical signal of a wavelength that is more conducive to the pump light conversion process of the erbium-doped optical fiber 20, which can further improve the conversion efficiency of the signal light.

[0032] In this embodiment, the reflection unit 20 includes a fiber Bragg grating 21 , and the fiber Bragg grating 21 is disposed between the input end 10 and the wavelength division multiplexer 30 .

[0033] By setting the fiber Bragg grating 21, the optical signal of a specific wavelength in the reverse spontaneous emission optical signal generated by the erbium-doped optical fiber 40 can be reflected back to the erbium-doped optical fiber 40 through the wavelength division multiplexer 30, effectively reducing the optical power of the reverse spontaneous emission optical signal of the overall erbium-doped fiber amplifier 1 and improving the noise performance.

[0034] The fiber Bragg grating 21 is a fiber structure with a periodically changing core refractive index. Its core function is to form a narrow-band filter or reflector by forming a grating with a periodic spatial phase distribution in the core, thereby achieving the transmission or reflection of light of a specific wavelength. The fiber Bragg grating 21 can selectively reflect light signals of a specific wavelength, thereby achieving the function of a wavelength-selective optical filter.

[0035] In another embodiment, the reflection unit 20 includes a reflection plate, which is disposed between the input end 10 and the wavelength division multiplexer 30 , and a reflection film is disposed on a side of the reflection plate facing the wavelength division multiplexer 30 .

[0036] By setting a reflector, the reflective film on the reflector can reflect the optical signal of a specific wavelength in the reverse spontaneous radiation optical signal generated by the erbium-doped optical fiber 40 and return it to the erbium-doped optical fiber 40 through the wavelength division multiplexer 30, effectively reducing the optical power of the reverse spontaneous radiation optical signal of the overall erbium-doped fiber amplifier 1, greatly improving the conversion efficiency of the signal light, and improving the noise performance.

[0037] In this embodiment, reference Figure 1The erbium-doped fiber amplifier 1 further includes a first optical isolator 70 for isolating a reverse optical signal. The first optical isolator 70 is disposed between the input end 10 and the fiber Bragg grating 21 .

[0038] An optical isolator is a passive device that allows light to pass in one direction but prevents it from passing in the opposite direction. Its function is to limit the direction of light so that light can only be transmitted in one direction. The light reflected by the optical fiber echo can be well isolated by the optical isolator, thereby improving the efficiency of light wave transmission.

[0039] The optical signal input from the input end 10 is transmitted to the fiber Bragg grating 21 via the first optical isolator 70. The first optical isolator 70 isolates the optical signal transmitted in the reverse direction, that is, it can isolate the optical signal transmitted from the fiber Bragg grating 21 to the input end 10, thereby preventing the device connected to the input end 10 from being affected, so that the device can output a stable optical signal.

[0040] refer to Figure 1 The erbium-doped fiber amplifier 1 also includes a first optical splitter 80 and an input optical power monitoring unit 90. The first optical splitter 80 is arranged between the input end 10 and the first optical isolator 70. The first optical splitter 80 is used to split the input optical signal to the input optical power monitoring unit 90. The input optical power monitoring unit 90 is used to assist in monitoring the optical power of the input optical signal.

[0041] By setting the first optical splitter 80 and the input optical power monitoring unit 90, the input optical signal can be split, and the input optical power monitoring unit 90 can be used to perform auxiliary monitoring on the input optical signal power, so as to help the operator understand the power level of the optical signal in real time and ensure that the erbium-doped fiber amplifier 1 operates within the normal range; optical power monitoring can also help to timely discover faults or problems in the system; according to the monitored optical power level, the operator can also adjust the output power of the connected device to meet the system requirements or optimize the transmission performance. This real-time adjustment can improve the flexibility and adaptability of the system.

[0042] Specifically, the input optical power monitoring unit 90 includes a first photodiode 91 for receiving the optical signal split by the first optical splitter 80. The positive electrode of the first photodiode 91 can be connected to an external power supply, and the negative electrode can be connected to an external control unit.

[0043] A photodiode is a semiconductor device that converts light into electric current. Between the p (positive) and n (negative) layers, there is an intrinsic layer. A photodiode accepts light energy as input to generate an electric current. A photodiode is also called a photodetector, photoelectric sensor or light detector.

[0044] The first photodiode 91 can detect the change of light in real time and quickly output the corresponding electrical signal. The external control unit can obtain the electrical signal and then obtain the optical power, which is convenient for further monitoring of the optical power.

[0045] In this embodiment, reference Figure 1 The erbium-doped fiber amplifier 1 further includes a second optical isolator 100 for isolating a reverse optical signal. The second optical isolator 100 is disposed between the output end 50 and the erbium-doped fiber 40 .

[0046] The forward optical signal output by the erbium-doped optical fiber 40 is transmitted to the output end 50 via the second optical isolator 100. The second optical isolator 100 isolates the reversely transmitted optical signal, that is, it can isolate the optical signal transmitted from the output end 50 to the erbium-doped optical fiber 40, reducing the reflection of the optical signal and the interference to the erbium-doped optical fiber 40.

[0047] In this embodiment, the erbium-doped fiber amplifier 1 also includes a second splitter 110 and an output optical power monitoring unit 120. The second splitter 110 is arranged between the second optical isolator 100 and the output end 50. The second splitter 110 is used to split the output forward optical signal to the output optical power monitoring unit 120. The output optical power monitoring unit 120 is used to assist in monitoring the optical power of the output forward optical signal.

[0048] By setting up the second optical splitter 110 and the output optical power monitoring unit 120, the output forward optical signal can be split, and the output optical power monitoring unit 120 is used to perform auxiliary monitoring on the output forward optical signal power, so as to help the operator understand the power level of the optical signal in real time and ensure that the erbium-doped fiber amplifier 1 operates within the normal range; optical power monitoring can also help to timely discover faults or problems in the system; according to the monitored optical power level, the operator can also adjust the output power of the connected device to meet the system requirements or optimize the transmission performance. This real-time adjustment can improve the flexibility and adaptability of the system.

[0049] Specifically, the output optical power monitoring unit 120 includes a second photodiode 121, which receives the forward optical signal split by the second optical splitter 110. The anode of the second photodiode 121 can be connected to an external power supply, and the cathode can be connected to an external control unit.

[0050] The second photodiode 121 can detect the change of light, that is, the output light signal, in real time, and quickly output the corresponding electrical signal. The external control unit can obtain the electrical signal and then obtain the optical power, which is convenient for monitoring the optical power.

[0051] The optical path transmission of the erbium-doped fiber 40 amplifier 1 of this embodiment is as follows: an external optical signal is input through the input terminal 10, and is transmitted to the wavelength division multiplexer 30 after passing through the first optical splitter 80, the first optical isolator 70, and the fiber Bragg grating 21 in sequence. The wavelength division multiplexer 30 combines the optical signal transmitted by the fiber Bragg grating 21 and the pump light of the pump unit 60, and transmits them to the erbium-doped fiber 40 for amplification. The forward optical signal output by the erbium-doped fiber 40 is output through the output terminal 50 after passing through the second optical isolator 100 and the second optical splitter 110 in sequence. Among them, the first splitter 80 splits a part of the input optical signal and introduces it into the first photodiode 91, and the first photodiode 91 converts the optical signal into an electrical signal to assist in monitoring the optical power of the input signal; the second splitter 110 splits a part of the forward optical signal output by the erbium-doped optical fiber 40 and introduces it into the second photodiode 121, and the second photodiode 121 converts the optical signal into an electrical signal to assist in monitoring the optical power of the output forward optical signal; the fiber Bragg grating 21 also reflects the optical signal of a specific wavelength in the reverse spontaneous radiation optical signal generated by the erbium-doped optical fiber 40, and returns it to the erbium-doped optical fiber 40 via the wavelength division multiplexer 30.

[0052] The present application also provides an optical communication system, referring to Figure 1 and Figure 2 The optical communication system includes a light source 2, a light receiving device 3 and the erbium-doped fiber amplifier 1 as described above. The input end 10 of the erbium-doped fiber amplifier 1 receives the optical signal of the light source 2, and the output end 50 transmits the amplified forward optical signal to the light receiving device 3.

[0053] The erbium-doped fiber amplifier 1 in the optical communication system of the present application is provided with a pump unit 60 and an input end 10, a reflection unit 20, a wavelength division multiplexer 30, an erbium-doped fiber 40 and an output end 50 which are provided in sequence. The pump unit 60 provides pump light and inputs it to the wavelength division multiplexer 30. The external optical signal is transmitted to the wavelength division multiplexer 30 via the input end 10 and the reflection unit 20 in sequence. The wavelength division multiplexer 30 combines the optical signal transmitted by the reflection unit 20 with the pump light and transmits the combined optical signal to the erbium-doped fiber 40 for amplification. The amplified forward optical signal is output via the output end 50. The setting of the reflection unit 20 can reflect the optical signal of a specific wavelength in the reverse spontaneous emission optical signal generated by the erbium-doped fiber 40 and return it to the erbium-doped fiber 40 via the wavelength division multiplexer 30, thereby effectively reducing the optical power of the reverse spontaneous emission optical signal of the overall erbium-doped fiber amplifier 1, and at the same time, reducing energy waste, improving the conversion efficiency of the signal light, and improving the noise performance.

[0054] The light source 2 can output an optical signal in the L band or the L++ band.

[0055] The optical receiving device 3 can receive the optical signal output by the erbium-doped fiber amplifier 1 and perform subsequent transmission or processing operations.

[0056] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present utility model rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present utility model.

Claims

1. An erbium-doped fiber amplifier, characterized in that: The invention comprises a pump unit and an input end, a reflection unit, a wavelength division multiplexer, an erbium-doped optical fiber and an output end which are arranged in sequence. The pump unit is used to provide pump light and input it into the wavelength division multiplexer. An external optical signal is transmitted to the wavelength division multiplexer via the input end and the reflection unit in sequence. The wavelength division multiplexer combines the optical signal transmitted by the reflection unit with the pump light and transmits the combined optical signal to the erbium-doped optical fiber for amplification. The amplified forward optical signal is output via the output end. The reverse spontaneous radiation optical signal generated by the erbium-doped optical fiber is transmitted to the reflection unit. The reflection unit reflects the optical signal of a specific wavelength and returns to the erbium-doped optical fiber via the wavelength division multiplexer.

2. The erbium-doped fiber amplifier according to claim 1, characterized in that: The reflection unit comprises a fiber Bragg grating, and the fiber Bragg grating is arranged between the input end and the wavelength division multiplexer.

3. The erbium-doped fiber amplifier according to claim 2, characterized in that: The erbium-doped fiber amplifier also includes a first optical isolator for isolating a reverse optical signal. The first optical isolator is arranged between the input end and the fiber Bragg grating. The optical signal input from the input end is transmitted to the fiber Bragg grating via the first optical isolator.

4. The erbium-doped fiber amplifier according to claim 3, characterized in that: The erbium-doped fiber amplifier also includes a first optical splitter and an input optical power monitoring unit. The first optical splitter is arranged between the input end and the first optical isolator. The first optical splitter is used to split the input optical signal to the input optical power monitoring unit. The input optical power monitoring unit is used to assist in monitoring the optical power of the input optical signal.

5. The erbium-doped fiber amplifier according to claim 4, characterized in that: The input optical power monitoring unit comprises a first photodiode, which is used to receive the optical signal split by the first optical splitter.

6. The erbium-doped fiber amplifier according to claim 4, characterized in that: The erbium-doped fiber amplifier also includes a second optical isolator for isolating a reverse optical signal. The second optical isolator is arranged between the output end and the erbium-doped fiber. The forward optical signal output by the erbium-doped fiber is transmitted to the output end via the second optical isolator.

7. The erbium-doped fiber amplifier according to claim 6, characterized in that: The erbium-doped fiber amplifier also includes a second optical splitter and an output optical power monitoring unit. The second optical splitter is arranged between the second optical isolator and the output end. The second optical splitter is used to split the output forward optical signal to the output optical power monitoring unit. The output optical power monitoring unit is used to assist in monitoring the optical power of the output forward optical signal.

8. The erbium-doped fiber amplifier according to claim 7, characterized in that: The input optical power monitoring unit includes a second photodiode, which is used to receive the forward optical signal split by the second optical splitter.

9. The erbium-doped fiber amplifier according to claim 1, characterized in that: The reflection unit comprises a reflection plate, which is arranged between the input end and the wavelength division multiplexer, and a reflection film is arranged on a side of the reflection plate facing the wavelength division multiplexer.

10. An optical communication system, characterized in that: It comprises a light source, a light receiving device and an erbium-doped fiber amplifier as described in any one of claims 1 to 9, wherein the input end of the erbium-doped fiber amplifier receives the light signal of the light source, and the output end transmits the amplified forward light signal to the light receiving device.

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