CN215734279U - Detection system for improving dynamic range of optical time domain reflectometer - Google Patents
Detection system for improving dynamic range of optical time domain reflectometer Download PDFInfo
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- CN215734279U CN215734279U CN202122149221.3U CN202122149221U CN215734279U CN 215734279 U CN215734279 U CN 215734279U CN 202122149221 U CN202122149221 U CN 202122149221U CN 215734279 U CN215734279 U CN 215734279U
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Abstract
The utility model discloses a detection system for improving the dynamic range of an optical time domain reflectometer, which has the technical scheme key points that: the photoelectric detection circuit is electrically connected with an AD acquisition circuit, the photoelectric detection circuit comprises an APD, the APD is electrically connected with a transimpedance amplifier, the transimpedance amplifier is electrically connected with a secondary amplifier, the secondary amplifier is electrically connected with a tertiary amplifier, the tertiary amplifier is electrically connected with a quaternary amplifier, the quaternary amplifier is electrically connected with an analog switch, and the analog switch is electrically connected with an AD processing circuit; the utility model effectively solves the problem of low dynamic range of the traditional OTDR, and the optical fiber loss and the length of 120km under ideal conditions can be monitored by adopting the scheme.
Description
Technical Field
The utility model relates to the technical field of electronics, in particular to a detection system for improving the dynamic range of an optical time domain reflectometer.
Background
In recent years, optical communication is rapidly developed, and the traffic of data communication is continuously increased, so that the data communication becomes one of the fastest-developing services in a telecommunication network; copper cables are gradually eliminated due to inherent defects of the copper cables, and optical fiber communication is widely applied to the communication field due to the advantages of large bandwidth, large capacity, strong anti-interference capability, small loss and the like.
During engineering construction, the integrity of the optical fiber is damaged unintentionally, and the damage cannot be identified by human eyes, so that the fault position in the optical fiber needs to be detected by means of OTDR. Therefore, OTDR is a very necessary and necessary measurement tool in a communication link.
At present, the measurement distance of OTDR at home and abroad is mostly within 80km, if 120km is expected to be measured, a typical optical fiber attenuation value at 1550nm is assumed to be 0.2dB/km, and a welding point (the welding point loss is 0.1dB) is arranged at every 2km, so that the required dynamic range is about 30 dB. Since the optical pulse actually goes one round trip in the fiber, the attenuation amplitude is effectively doubled, and thus 60dB is achieved.
SUMMERY OF THE UTILITY MODEL
In view of the problems mentioned in the background art, it is an object of the present invention to provide a detection system for improving the dynamic range of an optical time domain reflectometer, so as to solve the problems mentioned in the background art.
The technical purpose of the utility model is realized by the following technical scheme:
the utility model provides an improve optical time domain reflectometer dynamic range's detecting system, includes the photoelectric detection circuit, electric connection has AD acquisition circuit on the photoelectric detection circuit, including the APD among the photoelectric detection circuit, the electric connection has the transimpedance amplifier on the APD, the last electric connection of transimpedance amplifier has the second grade amplifier, the electric connection has tertiary amplifier on the second grade amplifier, the electric connection has the level four amplifier on the tertiary amplifier, the electric connection has analog switch on the level four amplifier, the electric connection has AD processing circuit on the analog switch.
By adopting the technical scheme, the problem of low dynamic range of the traditional OTDR is effectively solved, the loss and the length of 120km optical fiber under ideal conditions can be monitored after the scheme is adopted, the photoelectric detection circuit firstly adopts a high-sensitivity detector to convert optical signals into electric signals and then passes through three-stage low-noise amplifiers, the AD acquisition circuit acquires the signals behind each stage of amplifier at different moments through an analog switch by using a time division multiplexing method and finally sends the signals into an embedded processor for processing, the conversion of the signals can be effectively realized, and the noise reduction and the amplification processing can be realized.
Preferably, the photoelectric detection circuit is electrically connected with a circulator, and the circulator is respectively and electrically connected with a pulse laser and an optical fiber to be detected.
By adopting the technical scheme, the laser pulse signal generation device is used for generating the laser pulse signal and receiving and transmitting the pulse signal.
Preferably, the pulse laser is a semiconductor diode laser, and the pulse laser comprises a pulse control laser which provides pulses with four different pulse widths, namely 20ns, 100nm, 500ns and 1 us.
By adopting the technical scheme, the pulse laser selects a Fabry-Perot (F-P) semiconductor diode laser with mature process and low cost, and four pulse control lasers with different pulse widths are provided for the Fabry-Perot (F-P) semiconductor diode laser.
Preferably, the transimpedance amplifier adopts an OPA847 operational amplifier with high gain-bandwidth product and low noise.
By adopting the technical scheme, the OPA847 operational amplifier can effectively process pulse information and effectively reduce noise.
Preferably, the analog switch 12 is a 1 × 4 analog switch, and the 1 × 4 analog switch receives the amplified signal.
By adopting the technical scheme, the multichannel analog switch 12 is convenient to control and adjust, and multichannel input signals are realized.
Preferably, the AD acquisition circuit includes the AD processing circuit and the analog switch.
By adopting the technical scheme, the AD acquisition circuit can be set to control, regulate and process signals.
In summary, the utility model mainly has the following beneficial effects:
the utility model effectively solves the problem of low dynamic range of the traditional OTDR, and can monitor the optical fiber loss and length of 120km under ideal conditions by adopting the scheme, the photoelectric detection circuit firstly adopts a high-sensitivity detector to convert optical signals into electric signals, and then the electric signals pass through three-stage low-noise amplifiers, the AD acquisition circuit respectively acquires the signals behind each stage of amplifier at different moments through an analog switch by using a time division multiplexing method, and finally the signals are sent into an embedded processor for processing, so that the conversion of the signals can be effectively realized, and the noise reduction and amplification processing can be realized.
Drawings
FIG. 1 is a schematic diagram of the system architecture of the present invention;
fig. 2 is a schematic diagram of a photoelectric detection circuit and an AD acquisition circuit of the present invention.
Reference numerals: 1. a pulsed laser; 2. a circulator; 3. an optical fiber to be tested; 4. a photodetection circuit; 5. an AD acquisition circuit; 6. an embedded processor; 7. APD; 8. a transimpedance amplifier; 9. a secondary amplifier; 10. a three-stage amplifier; 11. a four-stage amplifier; 12. an analog switch; 13. an AD processing circuit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Examples
Referring to fig. 1-2, a detection system for improving a dynamic range of an optical time domain reflectometer includes a photodetection circuit 4, the photodetection circuit 4 is electrically connected to an AD acquisition circuit 5, the photodetection circuit 4 includes an APD7, the APD7 is electrically connected to a transimpedance amplifier 8, the transimpedance amplifier 8 is electrically connected to a secondary amplifier 9, the secondary amplifier 9 is electrically connected to a tertiary amplifier 10, the tertiary amplifier 10 is electrically connected to a quaternary amplifier 11, the quaternary amplifier 11 is electrically connected to an analog switch 12, and the analog switch 12 is electrically connected to an AD processing circuit 13.
By adopting the technical scheme, the problem of low dynamic range of the traditional OTDR is effectively solved, the loss and the length of 120km optical fiber under ideal conditions can be monitored after the scheme is adopted, the photoelectric detection circuit 4 firstly adopts a high-sensitivity detector to convert optical signals into electric signals, then the electric signals pass through three levels of low-noise amplifiers, the AD acquisition circuit 5 acquires the signals of each level of amplifier at different moments through the analog switch 12 by using a time division multiplexing method and finally sends the signals into the embedded processor 6 for processing, the conversion of the signals can be effectively realized, and the noise reduction and the amplification processing can be realized.
In this embodiment, preferably, the photodetection circuit 4 is electrically connected to a circulator 2, and the circulator 2 is respectively electrically connected to a pulse laser 1 and an optical fiber 3 to be detected. The effect is that the laser pulse signal is generated and the pulse signal is received and transmitted.
In this embodiment, it is preferable that the pulse laser 1 is a semiconductor diode laser, and the pulse laser 1 includes a pulse control laser that provides pulses of four different pulse widths, 20ns, 100nm, 500ns, and 1 us. The pulse laser 1 has the effects that a Fabry-Perot F-P semiconductor diode laser with mature technology and low cost is selected and four pulse control lasers with different pulse widths are provided for the Fabry-Perot F-P semiconductor diode laser.
In this embodiment, the transimpedance amplifier 8 preferably employs an OPA847 operational amplifier with a high gain-bandwidth product and low noise. The OPA847 operational amplifier has the advantages that pulse information can be effectively processed, and noise is effectively reduced.
The analog switch 12 is a 1 × 4 analog switch, and the 1 × 4 analog switch receives the amplified signal. The effect is that the selection of the multichannel analog switch 12 is convenient for control and adjustment, and multichannel input signals are realized.
In this embodiment, it is preferable that the AD acquisition circuit 5 includes the AD processing circuit 13 and the analog switch 12. The effect is that the setting of the AD acquisition circuit 5 can realize the control, regulation and processing of the signals.
The use principle and the advantages are as follows:
the photoelectric detection circuit 4 firstly adopts a high-sensitivity detector to convert optical signals into electric signals, then the electric signals pass through the three-stage low-noise amplifier, the AD acquisition circuit 5 respectively acquires signals behind each stage of amplifier at different moments through the analog switch 12 by using a time division multiplexing method, and finally the signals are sent into the embedded processor 6 for processing.
The working principle of the system is as follows:
the pulse laser 1 selects a fabry-perot (F-P) semiconductor diode laser with mature process and low cost, and provides four pulse control lasers with different pulse widths, namely 20ns, 100nm, 500ns and 1us pulses. The laser emits pulsed light, the pulsed light is injected into the optical fiber to be detected through the circulator 2 to generate Rayleigh backscattering, the scattered light is received by the photoelectric detection circuit 4 after passing through the circulator 2, and the photoelectric detection circuit 4 is an Avalanche Photodiode (APD).
APD7 converts an optical signal into a current signal, which is converted into a voltage signal by pre-transimpedance amplifier 8, which transimpedance amplifier 8 selects an OPA847 operational amplifier with high gain-bandwidth product and low noise.
After passing through the first-stage trans-impedance amplifier 8, the signal continues to pass through the second-stage amplifier 9, the third-stage amplifier 10 and the fourth-stage amplifier 11 for amplification, and the signal amplified at each stage enters a 1 × 4 analog switch 12.
The AD acquisition circuit 5 acquires the signal of the secondary amplifier 9 in the first 10s and performs cumulative averaging, acquires the signal of the tertiary amplifier 10 in the next 10s and performs cumulative averaging, and acquires the signal of the quaternary amplifier 11 in the last 10s and performs cumulative averaging. Finally, the embedded processor 6 splices the first 0-4km signals of the second-level amplifier 9, the first 4-8km signals of the third-level amplifier 10 and the first 8-12km signals of the fourth-level amplifier 11 together after dividing by the amplification factor, and outputs the final monitoring curve.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. The utility model provides an improve detecting system of optical time domain reflectometer dynamic range which characterized in that: including photoelectric detection circuit (4), the electrical connection has AD acquisition circuit (5) on photoelectric detection circuit (4), including APD (7) in photoelectric detection circuit (4), the electrical connection has transimpedance amplifier (8) on APD (7), the electrical connection has second grade amplifier (9) on transimpedance amplifier (8), the electrical connection has tertiary amplifier (10) on second grade amplifier (9), the electrical connection has level four amplifier (11) on tertiary amplifier (10), the electrical connection has analog switch (12) on level four amplifier (11), analog switch (12) electrical connection has AD processing circuit (13).
2. The detection system for improving the dynamic range of an optical time domain reflectometer as in claim 1, wherein: the photoelectric detection circuit (4) is electrically connected with a circulator (2), and the circulator (2) is respectively and electrically connected with a pulse laser (1) and an optical fiber (3) to be detected.
3. The detection system for improving the dynamic range of an optical time domain reflectometer as in claim 2, wherein: the pulse laser (1) adopts a semiconductor diode laser, and the pulse laser (1) comprises a pulse control laser.
4. The detection system for improving the dynamic range of an optical time domain reflectometer as in claim 3, wherein: the pulse control laser provides pulses of four different pulse widths, 20ns, 100nm, 500ns and 1 us.
5. The detection system for improving the dynamic range of an optical time domain reflectometer as in claim 1, wherein: the trans-impedance amplifier (8) adopts an OPA847 operational amplifier with high gain-bandwidth product and low noise.
6. The detection system for improving the dynamic range of an optical time domain reflectometer as in claim 1, wherein: the analog switch (12) adopts a 1 × 4 analog switch, and the 1 × 4 analog switch receives the amplified signal.
7. The detection system for improving the dynamic range of an optical time domain reflectometer as in claim 1, wherein: the AD acquisition circuit (5) comprises the AD processing circuit (13) and the analog switch (12).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202122149221.3U CN215734279U (en) | 2021-09-07 | 2021-09-07 | Detection system for improving dynamic range of optical time domain reflectometer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202122149221.3U CN215734279U (en) | 2021-09-07 | 2021-09-07 | Detection system for improving dynamic range of optical time domain reflectometer |
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| CN215734279U true CN215734279U (en) | 2022-02-01 |
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