CN115360577A - Input detection system of optical fiber amplifier - Google Patents

Input detection system of optical fiber amplifier Download PDF

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Publication number
CN115360577A
CN115360577A CN202210928522.2A CN202210928522A CN115360577A CN 115360577 A CN115360577 A CN 115360577A CN 202210928522 A CN202210928522 A CN 202210928522A CN 115360577 A CN115360577 A CN 115360577A
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China
Prior art keywords
optical fiber
optical
light
signal light
amplifying
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CN202210928522.2A
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Chinese (zh)
Inventor
姜倩文
梅坤
徐雅燕
林瑜佳
胡兆
李文康
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Shanghai Radio Equipment Research Institute
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Shanghai Radio Equipment Research Institute
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/0014—Monitoring arrangements not otherwise provided for
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/094042—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a fibre laser
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
    • H01S3/107—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using electro-optic devices, e.g. exhibiting Pockels or Kerr effect

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Optical Communication System (AREA)

Abstract

The invention discloses an input detection system of an optical fiber amplifier, which comprises: the device comprises an optical fiber coupling unit, a gain pre-amplification unit and a light detection unit, wherein the optical fiber coupling unit is used for coupling spatial signal light into an optical fiber; the gain pre-amplifying unit is used for gain amplifying the space signal light; the optical detection unit is used for detecting the amplified spatial signal light so as to detect the input optical power of the optical fiber amplifier and outputting a feedback signal to the optical fiber coupling unit; and the optical fiber coupling unit adjusts the coupling position of the space signal light and the optical fiber according to the feedback signal so as to maximize the light intensity of the space signal light in the optical fiber. The invention firstly amplifies the space signal light gain and then detects the light power, the light energy of the signal is lossless, the receiving sensitivity of the receiving end of the laser communication link is greatly improved, the effectiveness and the stability of the communication link can be monitored in real time according to the detection result, and the coupling efficiency of the space signal light and the optical fiber amplifier is improved.

Description

Input detection system of optical fiber amplifier
Technical Field
The invention relates to the technical field of space laser communication, in particular to an input detection system of an optical fiber amplifier at a space laser communication receiving end.
Background
The space laser communication is a communication technology which uses laser with extremely short wavelength as an information carrier to establish communication links between satellites, between the air and the ground of the satellites or between the satellites and the ground and realize high-speed data transmission. Compared with space microwave communication, laser communication has the advantages of high communication rate, large information capacity, small size, low power consumption and the like, and has great application prospect in constructing space high-speed networking with integration of space and ground.
The receiving end of the space laser communication system is used for collecting space signal beams emitted by the emitting end of a target satellite, required communication information is recovered after signal processing, and an erbium-doped fiber amplifier (EDFA) is used for the receiving end of the space laser communication system and becomes a research hotspot in recent years. For the laser communication system amplified by the optical fiber, the received space signal light needs to be coupled into the single-mode optical fiber for amplification, and as the fiber core of the single-mode optical fiber is very small, usually 8-10 μm, the light spot deviation caused by the coupling error can reduce the signal light energy entering the optical fiber from the receiving end, influence the stability of laser communication and increase the system error rate. In order to ensure that a communication link is stable and reliable, the input optical power of the EDFA at the receiving end needs to be monitored to quickly judge the effectiveness of establishment of the communication link, but due to the influence of space loss of a transmission link, signal light reaching the receiving end is very weak, direct light splitting detection is difficult, and a part of signal light energy is lost, so that the receiving sensitivity and the communication distance of a communication system are influenced.
Disclosure of Invention
The invention provides an input detection system of an optical fiber amplifier, which is used for detecting the input optical power of the optical fiber amplifier after amplifying space signal light, and adjusting the coupling position of the space signal light and an optical fiber according to the detection result, thereby greatly improving the receiving sensitivity of a communication link and the aiming coupling precision of the optical fiber.
In order to achieve the above object, the present invention provides an input detection system of an optical fiber amplifier, comprising:
the optical fiber coupling unit is used for coupling the space signal light into an optical fiber and adjusting the coupling position of the space signal light and the optical fiber according to a feedback signal output by the optical detection unit so as to maximize the light intensity of the space signal light in the optical fiber;
the gain pre-amplification unit is connected with the output end of the optical fiber coupling unit and is used for performing gain amplification on the space signal light; and
and the optical detection unit is connected with the output end of the gain pre-amplification unit and used for detecting the amplified spatial signal light so as to detect the input optical power of the optical fiber amplifier and outputting a feedback signal to the optical fiber coupling unit.
Further, the optical fiber coupling unit includes:
a receiving optical system for receiving the spatial signal light and coupling into the optical fiber;
and the self-adaptive regulator is connected with the receiving optical system and is used for regulating the coupling position of the space signal light and the optical fiber according to a feedback signal.
Further, the gain pre-amplifying unit includes:
an amplification section including at least one stage of optical path amplification module to amplify the spatial signal light in stages;
and the light splitting part is connected with the output end of the amplifying part and is used for dividing the amplified space signal light into two paths, wherein one path of the amplified space signal light is input to a main light path of the optical fiber amplifier, and the other path of the amplified space signal light is input to the light detection unit.
Furthermore, the optical path amplification module comprises a first optical isolator, a first wavelength division multiplexer and a gain optical fiber which are connected through optical fibers, and the input end of the wavelength division multiplexer is further connected with pump light.
Further, the light splitting part comprises a second wavelength division multiplexer, a second optical isolator, a filter and a light splitter which are connected through an optical fiber, wherein the second wavelength division multiplexer is used for separating the residual pump light and the amplified space signal light output by the amplifying part and transmitting the residual pump light to a main optical path of the optical fiber amplifier.
Further, if the amplifying part comprises two or more stages of optical path amplifying modules, a third wavelength division multiplexer is arranged between two adjacent stages of optical path amplifying modules, and the third wavelength division multiplexer is used for separating the residual pump light output by the previous stage of optical path amplifying module and the spatial signal light after the stage amplification and transmitting the residual pump light to the input end of the first wavelength division multiplexer of the next stage of optical path amplifying module.
Further, the gain fiber is a rare earth doped fiber.
Further, the gain fiber is an erbium-doped fiber.
Further, the light detection unit includes:
the photoelectric detector is connected with the output end of the gain pre-amplifying circuit and used for converting the amplified space signal light into photocurrent;
and the photoelectric detection circuit is connected with the output end of the photoelectric detector, and the photoelectric detector comprises a logarithmic amplifier and is used for analyzing the optical power of the input end of the optical fiber amplifier according to the photocurrent and outputting a feedback signal to the self-adaptive regulator.
The invention has the following advantages:
(1) The invention carries out light splitting and detection after the weak space signal light at the input end of the optical fiber amplifier is amplified by the gain pre-amplifying unit, and compared with the traditional optical fiber amplifier input detection method in which the light is split directly at the input end, the method has no loss of signal light energy; the optical power entering the photoelectric detector is improved, the pressure of a detection circuit is reduced, the receiving sensitivity of a receiving end of a laser communication link can be greatly improved, and the method has important significance for long-distance space laser communication;
(2) The optical detection unit adopts a logarithmic amplifier, has the advantages of simple structure, low noise and high sensitivity, can monitor the effectiveness and stability of a communication link in real time, and simultaneously is used as a feedback signal of a self-adaptive regulator, so that the coupling error between a receiving optical system and an optical fiber connector is reduced, and the coupling efficiency is improved;
(3) The invention is simple and reliable, is suitable for all space laser communication systems applying erbium-doped fiber amplification, has better universality and is a feasible scheme for improving the receiving sensitivity of space laser communication.
Drawings
FIG. 1 is a schematic structural diagram of an input detection system according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an input detection system according to another embodiment of the present invention;
fig. 3 is a schematic structural diagram of an input detection system according to still another embodiment of the invention.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise ratio for the purpose of facilitating and distinctly aiding in the description of the embodiments of the invention.
Because the optical signal power of the input end of the optical fiber amplifier is very weak, usually (-50 to-40) dBm, the direct light-splitting detection is difficult, and the conventional photoelectric detection device is difficult to meet the requirements. Meanwhile, the coupling efficiency of the optical fiber at the receiving end is reduced due to the influence of system temperature, vibration and the like, and the communication quality and the receiving sensitivity of a communication link are seriously influenced. The invention provides an input detection system of an optical fiber amplifier, which is positioned at the input end of the optical fiber amplifier, and is used for performing gain amplification on spatial signal light at the input end of the optical fiber amplifier and then performing light splitting detection on the optical power of the signal light at the input end of the optical fiber amplifier, so that the receiving sensitivity of a receiving end of a laser communication link can be greatly improved.
As shown in fig. 1 to 3, the input detection system of the optical fiber amplifier comprises: the device comprises an optical fiber coupling unit 1, a gain pre-amplification unit 2 and a light detection unit 3. The optical fiber coupling unit 1 is used for coupling the space signal light into an optical fiber; the input end of the gain pre-amplification unit 2 is connected with the output end of the optical fiber coupling unit 1, and is used for performing gain amplification on the spatial signal light and inputting the spatial signal light to a main optical path of an optical fiber amplifier; the input end of the optical detection unit 3 is connected with the output end of the gain pre-amplification unit 2, and is configured to detect the amplified spatial signal light to detect the input optical power of the optical fiber amplifier, and output a feedback signal to the optical fiber coupling unit 1, and the optical fiber coupling unit 1 adjusts the coupling position of the spatial signal light and the optical fiber according to the feedback signal, so that the light intensity of the spatial signal light in the optical fiber is maximized.
As shown in fig. 1, the optical fiber coupling unit 1 includes: the receiving optical system 4 receives the spatial signal light and couples the spatial signal light into an optical fiber; the adaptive regulator 5 is connected to the receiving optical system 4, and is configured to adjust a coupling position of the spatial signal light and the optical fiber according to a feedback signal. In this embodiment, the wavelength of the spatial signal light is 1550nm.
The gain pre-amplifying unit 2 includes: an amplifying part and a spectroscopic part. The amplifying part comprises at least one stage of optical path amplifying module to carry out graded pre-amplification on the space signal light. The light path amplification module comprises a first optical isolator 6, a first wavelength division multiplexer 8 and a gain optical fiber 9 which are connected through optical fibers, and the input end of the first wavelength division multiplexer 8 is further connected with pump light. The gain fiber 9 is a rare earth doped fiber, specifically an erbium doped fiber. The pump light in each stage of the optical path amplification module can be from mutually independent pump sources 7, that is, the input end of a first wavelength division multiplexer 8 in each stage of the optical path amplification module is connected with the pump source 7, the pump source 7 outputs the pump light, and the pump light is coupled to the gain fiber 9 through the first wavelength division multiplexer 8 and the spatial signal light output by the fiber coupling unit 1 or the pre-amplified spatial signal light output by the previous stage of the optical path amplification module; the pumping light source can also be from the same pumping source 7, in this case, a third wavelength division multiplexer 17 is disposed between two adjacent stages of optical path amplification modules, and the third wavelength division multiplexer 17 is configured to separate the residual pumping light output by the previous stage of optical path amplification module and the spatial signal light after the stage amplification, and transmit the residual pumping light to the input end of the first wavelength division multiplexer 8 of the next stage of optical path amplification module.
In this embodiment, the amplifying section includes a first-stage optical path amplifying module, as shown in fig. 1, the spatial signal light is coupled to the erbium-doped fiber through the first optical isolator 6, and the erbium-doped fiber is coupled to the pump light with a wavelength of 980nm generated by the pump source 7, the length of the erbium-doped fiber is 6m, and the spatial signal light can be pre-amplified by 10 to 20dB by adjusting the power of the pump light output by the pump source 7. In another embodiment, the amplifying section includes two stages of optical path amplifying modules, and the spatial signal output by the optical fiber coupling unit 1 is acted by the two stages of optical path amplifying modules to output spatial signal light with larger gain, as shown in fig. 2, the pump light in each stage of optical path amplifying module is derived from mutually independent pump sources 7. In another embodiment, the amplifying section includes two stages of optical path amplifying modules, and a third wavelength division multiplexer 17 is disposed between the two stages of optical path amplifying modules, as shown in fig. 3, the mixed signal light output by the first stage of optical path amplifying module is separated into a first stage of pre-amplified spatial signal light and a residual pump light by the third wavelength division multiplexer 17, and the residual pump light is output to the input end of the first wavelength division multiplexer 8 of the second stage of optical path amplifying module.
The input end of the light splitting part is connected with the output end of the amplifying part and is used for dividing the amplified space signal light into two paths, wherein one path is input to a main light path of the optical fiber amplifier, and the other path is input to the light detection unit 3. Specifically, the beam-splitting part contains optical fiber connection's second wavelength division multiplexer 10, second optoisolator 11, wave filter 12 and optical splitter 13, second wavelength division multiplexer 10 is used for separating amplify the remaining pump light of portion output and the space signal light after the preliminary amplification, and the space signal light of the preliminary amplification after the separation passes through second optoisolator 11, wave filter 12 and optical splitter 13 transmission in proper order, and passes through optical splitter 13 divide into two parts, and wherein most space signal light gets into the main light path, and the remaining pump light with the separation couples through fourth wavelength division multiplexer 14, participates in follow-up light amplification, and little part space signal light gets into light detection unit 3. In this embodiment, the splitting ratio of the splitter 13 is 98.
The light detection unit 3 includes: a photodetector 15, connected to the output end of the gain pre-amplifying unit 2, for converting a small part of the spatial signal light output by the gain pre-amplifying unit 2 into a photocurrent; and the photoelectric detection circuit 16 is connected with the output end of the photoelectric detector 15, and the photoelectric detection circuit 16 comprises a logarithmic amplifier and is used for analyzing the optical power of the input end of the optical fiber amplifier according to the photocurrent and outputting a feedback signal to the adaptive regulator 5.
Compared with the traditional input detection method of the optical fiber amplifier with the input end directly split, the method has the advantages that the signal light energy is lossless, the light power entering the light detection unit 3 is improved, the pressure of a detection circuit is reduced, and the receiving sensitivity of the receiving end of a laser communication link can be greatly improved. In addition, the invention adopts the logarithmic amplifier with simple structure, low noise and high sensitivity to detect the optical power at the input end of the optical fiber amplifier, can monitor the effectiveness and stability of a communication link in real time, and simultaneously is used as a feedback signal of the self-adaptive regulator to reduce the coupling error between a receiving optical system and an optical fiber joint, improve the coupling efficiency and maximize the light intensity of the spatial signal light in the optical fiber.
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims (9)

1. An input detection system for an optical fiber amplifier at an input end of the optical fiber amplifier, comprising:
the optical fiber coupling unit is used for coupling the space signal light into an optical fiber and adjusting the coupling position of the space signal light and the optical fiber according to a feedback signal output by the optical detection unit so as to maximize the light intensity of the space signal light in the optical fiber;
the gain pre-amplification unit is connected with the output end of the optical fiber coupling unit, and is used for performing gain amplification on the spatial signal light and inputting the spatial signal light to a main optical path of the optical fiber amplifier; and
and the optical detection unit is connected with the output end of the gain pre-amplification unit and used for detecting the amplified spatial signal light so as to detect the input optical power of the optical fiber amplifier and outputting a feedback signal to the optical fiber coupling unit.
2. The input detection system of a fiber amplifier of claim 1, wherein the fiber coupling unit comprises:
a receiving optical system for receiving the spatial signal light and coupling into the optical fiber;
and the self-adaptive regulator is connected with the receiving optical system and is used for regulating the coupling position of the space signal light and the optical fiber according to a feedback signal.
3. The input detection system of a fiber amplifier of claim 1, wherein the gain pre-amplifying unit comprises:
an amplifying part including at least one stage of optical path amplifying module to amplify the spatial signal light in stages;
and the light splitting part is connected with the output end of the amplifying part and is used for dividing the amplified space signal light into two paths, wherein one path of the amplified space signal light is input to a main light path of the optical fiber amplifier, and the other path of the amplified space signal light is input to the light detection unit.
4. The input detection system of the optical fiber amplifier as claimed in claim 3, wherein the optical path amplifying module comprises a first optical isolator, a first wavelength division multiplexer and a gain fiber connected by an optical fiber, and the input end of the wavelength division multiplexer is further connected with a pump light.
5. The input detection system of the optical fiber amplifier according to claim 4, wherein the splitting section comprises a second wavelength division multiplexer, a second optical isolator, a filter and an optical splitter, which are connected to the optical fiber, and the second wavelength division multiplexer is configured to split the remaining pump light output from the amplifying section and the amplified spatial signal light and transmit the remaining pump light to a main optical path of the optical fiber amplifier.
6. The input detection system of claim 4, wherein if the amplifying section includes two or more stages of optical path amplifying modules, a third wavelength division multiplexer is disposed between two adjacent stages of optical path amplifying modules, and the third wavelength division multiplexer is configured to separate the residual pump light output by the previous stage of optical path amplifying module and the spatial signal light after the step amplification and transmit the residual pump light to an input end of the first wavelength division multiplexer of the next stage of optical path amplifying module.
7. The input detection system of a fiber amplifier of claim 4, wherein the gain fiber is a rare earth doped fiber.
8. The input detection system for a fiber amplifier of claim 7, wherein said gain fiber is an erbium doped fiber.
9. The input detection system of a fiber optic amplifier of claim 2, wherein the light detection unit comprises:
the photoelectric detector is connected with the output end of the gain pre-amplifying circuit and used for converting the amplified space signal light into photocurrent;
and the photoelectric detection circuit is connected with the output end of the photoelectric detector, and the photoelectric detector comprises a logarithmic amplifier and is used for analyzing the light power of the input end of the optical fiber amplifier according to the photocurrent and outputting a feedback signal to the self-adaptive regulator.
CN202210928522.2A 2022-08-03 2022-08-03 Input detection system of optical fiber amplifier Pending CN115360577A (en)

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Application Number Priority Date Filing Date Title
CN202210928522.2A CN115360577A (en) 2022-08-03 2022-08-03 Input detection system of optical fiber amplifier

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Application Number Priority Date Filing Date Title
CN202210928522.2A CN115360577A (en) 2022-08-03 2022-08-03 Input detection system of optical fiber amplifier

Publications (1)

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CN115360577A true CN115360577A (en) 2022-11-18

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