CN102170307B - Dynamic frequency offset correction method and coherence optical time-domain reflectometer system - Google Patents
Dynamic frequency offset correction method and coherence optical time-domain reflectometer system Download PDFInfo
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- CN102170307B CN102170307B CN201010601965.8A CN201010601965A CN102170307B CN 102170307 B CN102170307 B CN 102170307B CN 201010601965 A CN201010601965 A CN 201010601965A CN 102170307 B CN102170307 B CN 102170307B
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- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/31—Testing of optical devices, constituted by fibre optics or optical waveguides with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
- G01M11/3109—Reflectometers detecting the back-scattered light in the time-domain, e.g. OTDR
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Abstract
The invention discloses a dynamic frequency offset correction method and a coherence optical time-domain reflectometer system. The method comprises the steps of light splitting of laser output by a laser to generate probe light and control light; inputting the control light into an MZI for interference and performing photoelectric conversion on the interfered control light to obtain a first electric signal; controlling optical path difference of optical signal transmitted at two arms of the MZI according to the first electric signal so that the optical path difference is one quarter of the wavelength of the laser; according to the first electric signal, calculating a deviation degree of an actual central frequency of the laser relative to a standard value of the central frequency of the laser; and compensating correspondingly based on the deviation degree. According to the method of the present invention, the laser output from the laser is divided into the probe light and the control light and the deviation degree of the actual central frequency of the laser relative to the standard value of the central frequency of the laser is obtained according to the control light. In addition, the laser output from the laser is correspondingly corrected and controlled according to the deviation degree so as to improve performance of optical coherent detection.
Description
Technical field
The present invention relates to technical field of optical fiber communication, relate in particular to method and Coherent optical time domain reflectometer system that a kind of dynamic frequency offset is corrected.
Background technology
Along with the development of Fibre Optical Communication Technology, the fiberize of network is one of main trend of network Development always.And submarine fiber cable is the very important link of network fiberization, the Real-Time Monitoring of the extra large submarine fiber cable of long distance is also become to the important content of network operation.
When submarine fiber cable is detected, adopt Coherent optical time domain reflectometer (coherence optical time-domain reflectometer, hereinafter to be referred as COTDR) tested, in the COTDR system, because needs are surveyed the over distance laser reflection signal, the frequency drift of laser during measuring will have influence on the receiver receive frequency.For lossing signal not, need to enlarge the received passband of receiver, will cause pouring in of noise power thus, thereby cause the receiving system signal to noise ratio to descend.Therefore, the detection performance of COTDR will be limited by the frequency stability of light source.In traditional scheme, often want the high laser of frequency of utilization stability as light source, this can greatly increase the cost with the communication system of COTDR.
In the scheme of prior art, whether depart from centre frequency in the frequency of measuring laser and monitored, if depart from, light source is adjusted.But there is following shortcoming in prior art: due to very high to the light source linewidth requirements in COTDR, to the adjustment of light source frequency, can have influence on the light source live width, therefore, can have influence on the detection effect.
Summary of the invention
The invention provides method and Coherent optical time domain reflectometer system that a kind of dynamic frequency offset is corrected, in order to improve the coherent light detection performance, reduce the requirement to the light source live width, improve the effect of the rectification of frequency shift (FS).
A kind of method that the embodiment of the present invention provides dynamic frequency offset to correct, be applied in the impact that the frequency drift of eliminating laser in the Coherent optical time domain reflectometer system is brought, and comprising:
Laser to described laser output carries out light-splitting processing, generates and surveys light and control light;
Described control light is input in Mach-Zehnder interferometer MZI and is interfered, the control light after being interfered;
Control light after described interference is carried out to opto-electronic conversion, obtain first signal of telecommunication;
Be controlled at the optical path difference of the light signal transmitted on two arms of described MZI according to described first signal of telecommunication, make 1/4th of wavelength that described optical path difference is described laser;
According to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser;
According to the described degree of deviation, compensate accordingly, the practical center frequency of the baseband signal that makes the light signal of returning from downlink transmission obtain after receiving converges on the standard value of the centre frequency of described baseband signal.
The embodiment of the present invention also provides a kind of Coherent optical time domain reflectometer system, comprising: laser, the first optical splitter, Mach Zehnder interferometer MZI, photodetector, the first controller, second controller, modulator and modulation source;
Described laser, for generation of laser;
Described the first optical splitter, for described laser is carried out to light splitting, obtain surveying light and control light;
Described MZI, interfered the control light after being interfered for the described control light to input;
Described photodetector, carry out opto-electronic conversion for the control light by after described interference and obtain first signal of telecommunication;
Described the first controller, for according to described first signal of telecommunication, producing control signal, so that described MZI is controlled, 1/4th of the wavelength that the optical path difference that makes the light signal transmitted on two arms of described MZI is described laser;
Described modulator, for described detection light is modulated, generate detecting optical pulses;
Described modulation source, control described modulator for generation of modulator control signal described detection light modulated;
Described second controller, be used for according to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser, and based on the described degree of deviation, produce control signal and export the output frequency of described modulator control signal to control described modulation source, the practical center frequency of the described detecting optical pulses that makes described modulators modulate generate converges on the standard value of the centre frequency of described laser.
The embodiment of the present invention also provides a kind of Coherent optical time domain reflectometer system, described system comprises: laser, the first optical splitter, Mach Zehnder interferometer MZI, photodetector, the first controller, second controller, modulator, modulation source, coherent receiver, frequency mixer and oscillator;
Described laser, for generation of laser;
Described the first optical splitter, for described laser is carried out to light splitting, obtain surveying light and control light;
Described MZI, interfered the control light after being interfered for the described control light to input;
Described photodetector, carry out opto-electronic conversion for the control light by after described interference and obtain first signal of telecommunication;
Described the first controller, for according to described first signal of telecommunication, producing control signal, so that described MZI is controlled, 1/4th of the wavelength that the optical path difference that makes the light signal transmitted on two arms of described MZI is described laser;
Described modulator, for described detection light is modulated, generate detecting optical pulses;
Described modulation source, control described modulator for generation of modulator control signal described detection light modulated;
Described coherent receiver, for receiving the light signal of returning from the down link transmission, and, to the processing that is concerned with of the described light signal that transmission is returned from down link, obtain second signal of telecommunication;
Described oscillator, for generation of electric local oscillation signal;
Described frequency mixer, for described electric local oscillation signal and described second signal of telecommunication are carried out to mixing, obtain baseband signal;
Described second controller, be used for according to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser, and based on the described degree of deviation, produce the frequency of control signal with the described electric local oscillation signal of controlling described its output of oscillator tuning, the practical center frequency of the described baseband signal that makes described frequency mixer obtain converges on the standard value of the centre frequency of described laser.
The present invention is divided into the laser scribing of laser output to survey light and control light, according to the control photometry, calculates and obtains the degree of deviation of the practical center frequency of laser with respect to the standard value of the centre frequency of laser; According to this degree of deviation, compensate accordingly, the impact that drift was brought with the centre frequency of the laser of eliminating laser, improve the optical coherent detection performance, and can reduce the requirement to the light source live width.
The accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, below will the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described, apparently, accompanying drawing in the following describes is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.
The method flow diagram that Fig. 1 a corrects for the dynamic frequency offset that one embodiment of the invention provides;
The schematic diagram of the Coherent optical time domain reflectometer system that Fig. 1 b provides for one embodiment of the invention;
The schematic diagram of the Coherent optical time domain reflectometer system that Fig. 1 c provides for one embodiment of the invention;
The schematic diagram of the Coherent optical time domain reflectometer system that Fig. 1 d provides for one embodiment of the invention.
Embodiment
For the purpose, technical scheme and the advantage that make the embodiment of the present invention clearer, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, the every other embodiment that those of ordinary skills obtain under the prerequisite of not making creative work, belong to the scope of protection of the invention.
The embodiment of the present invention is detected by the frequency deviation to laser, and carry out the rectification of corresponding frequency shift (FS), eliminate thus the impact that the frequency drift of the laser of laser output is brought, can reduce the requirement of communication system to bandwidth, and improve the performance of Coherent optical time domain reflectometer system.
The method flow diagram that a kind of dynamic frequency offset that Fig. 1 a is depicted as one embodiment of the invention to be provided is corrected comprises:
In the present embodiment, by an optical splitter, as coupler, laser is carried out to light-splitting processing, generate and survey light and control light.The power of surveying light carries out fault location and detection for generation of detecting optical pulses to link fiber, and its power should be much larger than the power of controlling light, and optional, surveying light can be 99: 1 shown in figure with the ratio of controlling light.
In the present embodiment, use Mach Zehnder interferometer MZI to be interfered controlling light, the control light after being interfered, then carry out opto-electronic conversion to the control light after this interference, obtains first signal of telecommunication.Because the watt level of this first signal of telecommunication can reflect the optical path difference (optical path difference of the light signal also transmitted on two arms) of two arms in MZI, therefore can adjust according to this first signal of telecommunication the optical path difference of MZI two arms, making optical path difference is 1/4th of this laser, revises the impact that the extraneous factors such as temperature and vibration are surveyed MZI with this.MZI can pass through to adjust the dilatability of piezoelectric ceramic to adjust the optical path difference of MZI two arms.When the optical path difference of MZI two arms is just in time that four of optical maser wavelength/for the moment, the output of described MZI is in linear output area, the drift degree of the centre frequency of the laser of the light intensity of output and laser output is proportional.
After obtaining the degree of deviation of practical center frequency with respect to the standard value of laser center frequency of laser, the practical center frequency of the baseband signal that the light signal that can take following two kinds of modes to make to return the Coherent optical time domain reflectometer system from downlink transmission obtains after receiving converges on the standard value of the centre frequency of this baseband signal, to eliminate the impact that central frequency deviation was brought due to the laser of laser output.
Mode one: the light signal from down link that described detection light and described Coherent optical time domain reflectometer system the are received processing that is concerned with, the relevant light signal obtained of processing is carried out to opto-electronic conversion, obtain second signal of telecommunication; According to the described degree of deviation, control for described second signal of telecommunication, carrying out the frequency that mixing obtains the electric local oscillation signal of described baseband signal, make the practical center frequency of described baseband signal converge on the standard value of the centre frequency of described baseband signal.
Mode two: when described detection light being modulated to the generation detecting optical pulses, control the output frequency of the modulation source for carrying out described modulation according to the described degree of deviation, make the centre frequency convergence domain of described detecting optical pulses in the standard value of the centre frequency of described laser.
In the present embodiment, can will survey light by an optical splitter and be divided, and the part that marks off be surveyed to light and output to coherent receiver, by coherent receiver, to the light signal that transmission is returned from the down link processing that is concerned with, obtain second signal of telecommunication; Described electric local oscillation signal and described second signal of telecommunication are carried out to mixing, obtain baseband signal; Then according to the degree of deviation, control for described second signal of telecommunication, carrying out the frequency that mixing obtains the electric local oscillation signal of described baseband signal, make the practical center frequency of described baseband signal converge on the standard value of the centre frequency of described baseband signal.
The method of dynamic frequency offset being corrected below in conjunction with concrete application scenarios is specifically described, the Coherent optical time domain reflectometer system of the present embodiment can be system as shown in Figure 1 b, comprise: laser 1, coupler A2, photodetector 7, the first controllers 8, second controller 10, modulation source 11, modulator 12, and MZI5; Wherein, MZI5 comprises, coupler B3, piezoelectric ceramic 9 and coupler C6.
Below in conjunction with this Coherent optical time domain reflectometer system, describe the method that dynamic frequency offset is corrected in detail.
The luminous power of laser 1 output minute is done two-way output after coupler A2, and wherein most of power is exported on a road, as surveying light for detection; Another road power output is less, as controlling light for controlling.
Control the dividing of coupler B3 of light input MZI5 and make two-way, the coupler C6 that two-way light arrives MZI5 by different paths does relevant the processing, and its output light intensity will reflect the difference of two arm light paths.After MZI5 is interfered the control light of input, the control light input photodetector 7 obtained, after photodetector 7 carries out opto-electronic conversion to it, obtain first signal of telecommunication for controller, to produce control signal.
Photodetector 7 is given the first controller 8 by this first electric signal transmission.The first controller 8 is made control decision, produce control signal so that MZI5 is controlled, control the flexible optical path difference with adjusting MZI5 two arms of the piezoelectric ceramic 9 in MZI5, making optical path difference is 1/4th of this optical maser wavelength, revise the impact of the extraneous factors such as temperature and vibration on MZI5, make the output of MZI5 be in all the time linear output area.The first controller 8 just can have been revised the impact of extraneous factor on MZI5 to a certain extent on the FEEDBACK CONTROL of MZI5.
Further, also need to carry out the drift of following step with the centre frequency of the laser of further eliminating laser output.
The first signal of telecommunication input second controller 10 by described photodetector 7 outputs; According to this first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser by second controller 10; According to this degree of deviation, make corresponding control to compensate the drift of described laser center frequency by second controller 10.Second controller 10 is according to this degree of deviation, do control decision, when described detection light being modulated to the generation detecting optical pulses, control the output frequency of the modulation source 11 for carrying out modulation control according to the described degree of deviation, make the practical center frequency convergence domain of described detecting optical pulses in the standard value of the centre frequency of described laser.
After modulation source 11 having been carried out to adjustment, detection light enters modulator 12 and accepts modulation, generate detecting optical pulses, the centre frequency of this detecting optical pulses is corrected, enter monitored optical cable by up link 13, make the centre frequency of the detecting optical pulses of input optical cable be near standard value all the time.Because the centre frequency of the detecting optical pulses produced in the embodiment of the present invention is corrected, therefore the light signal of reflection and/or scattering occurs in this detecting optical pulses in optical fiber, after downlink transmission is returned the Coherent optical time domain reflectometer system, the practical center frequency of the baseband signal obtained through reception just can converge on the standard value of the centre frequency of this baseband signal, thereby has also just eliminated the impact that the central frequency deviation due to laser brings.
In another kind of application scenarios, the Coherent optical time domain reflectometer system can be designed to the system as shown in Fig. 1 c, comprising: laser 1, coupler A2, photodetector 7, the first controllers 8, second controller 10, modulation source 11, modulator 12 and MZI5; Wherein, MZI5 comprises, coupler B3, piezoelectric ceramic 9 and coupler C6.
On this basis, this system also comprises: coherent receiver 15, frequency mixer 17, oscillator 16 and baseband filter 18.
Below in conjunction with this Coherent optical time domain reflectometer system, describe the method that dynamic frequency offset is corrected in detail.
The luminous power of laser 1 output minute is done two-way output after coupler A2, and wherein most of power is exported on a road, as surveying light for detection; Another road power output is less, as controlling light for controlling.
Divide and make two-way after the coupler B3 of control light input MZI5, the coupler C6 that two-way light arrives MZI5 by different paths does relevant processing, and its output light intensity will reflect the difference of two arm light paths.After MZI5 is interfered the control light of input, the control light input photodetector 7 obtained, after photodetector 7 carries out opto-electronic conversion to it, obtain first signal of telecommunication for controller, to produce control signal.
In this system, modulation source 11 generation modulator control signals are controlled 12 pairs of described detection light of described modulator and are modulated; 12 pairs of described detection light of modulator are modulated, and generate detecting optical pulses.
Frequency mixer 17, for described electric local oscillation signal and described second signal of telecommunication are carried out to mixing, obtain baseband signal.
The method of rectification that the present embodiment carries out dynamic frequency offset is as follows:
The first signal of telecommunication input second controller 10 by described photodetector 7 outputs; According to this first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser by second controller 10; And based on the described degree of deviation, produce the frequency of control signal with the described electric local oscillation signal of controlling described oscillator 16 tuning its outputs, the practical center frequency of the described baseband signal that makes described frequency mixer 17 obtain converges on the standard value of the centre frequency of described laser, has realized thus the rectification of dynamic frequency offset.
In the present embodiment, can also will survey light by a coupler is divided, the part marked off is surveyed to light and output to coherent receiver, Coherent optical time domain reflectometer system now is as shown in Fig. 1 d, by coupler D, to survey light and be divided into two parts, part input modulator 12 is modulated, the processing that is concerned with of another part input coherent receiver 15 and the light signal that transmission is returned from down link, produce second signal of telecommunication, second controller 10 tuning rear generations electric local oscillation signal and this second signal of telecommunication carry out mixing, the practical center frequency of the baseband signal obtained converges on the standard value of the centre frequency of described baseband signal, realized thus the rectification of dynamic frequency offset.
The present embodiment is divided into the laser scribing of laser output to survey light and control light, according to the control photometry, calculates and obtains the degree of deviation of the practical center frequency of laser with respect to the standard value of the centre frequency of laser; Carry out corresponding compensation according to this degree of deviation and control, to eliminate the impact that central frequency deviation was brought of laser, improve the optical coherent detection performance, and can reduce the requirement to the light source live width.
One embodiment of the invention provides a kind of Coherent optical time domain reflectometer system, and the structural representation of this system can be referring to Fig. 1 c.Comprise: laser 1, the first optical splitter 2 (can be the coupler A in diagram), MZI5, photodetector 7, the first controller 5, second controller 10, modulator 12 and modulation source 11.
Described laser 1, for generation of laser;
Described the first optical splitter 2, for described laser is carried out to light splitting, obtain surveying light and control light;
Described MZI5, interfered the control light after being interfered for the described control light to input;
Described photodetector 7, carry out opto-electronic conversion for the control light by after described interference and obtain first signal of telecommunication;
Described the first controller 8, for according to described first signal of telecommunication, producing control signal, so that described MZI5 is controlled, 1/4th of the wavelength that the optical path difference that makes the light signal transmitted on two arms of described MZI5 is described laser;
Described modulator 12, for described detection light is modulated, generate detecting optical pulses;
Described modulation source 11, control 12 pairs of described detection light of described modulator for generation of modulator control signal and modulated;
Described second controller 10, be used for according to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser, and based on the described degree of deviation, produce control signal to control the output frequency of the described modulator control signal of described modulation source 11 output, the practical center frequency of the described detecting optical pulses that makes described modulator 12 modulation generate converges on the standard value of the centre frequency of described laser.
In addition, the described system of the present embodiment also further comprises: coherent receiver 15, and for receiving the light signal of returning from the down link transmission, and to the processing that is concerned with of the described light signal that transmission is returned from down link.
On the basis of the Coherent optical time domain reflectometer system based on shown in Fig. 1 c, can also will survey light by an optical splitter and be divided, the part marked off is surveyed to light and output to coherent receiver 15.Now need system is further improved, the structural representation of the Coherent optical time domain reflectometer system after improvement can be referring to shown in Fig. 1 d, now, described system also further comprises: the second optical splitter 4 (can be the coupler D in shown in Fig. 1 d), for from described detection light, separating a part of light, and be entered into described coherent receiver 15.
Mutual mechanism between each module of Coherent optical time domain reflectometer system in the present embodiment and function can, referring to the record of the corresponding embodiment of Fig. 1 a to Fig. 1 d, not repeat them here.
The present embodiment is divided into the laser scribing of laser output to survey light and control light, according to the control photometry, calculates and obtains the degree of deviation of the practical center frequency of laser with respect to the standard value of the centre frequency of laser; Carry out corresponding compensation according to this degree of deviation and control, to eliminate the impact that central frequency deviation was brought of laser, improve the optical coherent detection performance, and can reduce the requirement to the light source live width.
One embodiment of the invention provides a kind of Coherent optical time domain reflectometer system, and the structural representation of this system can be referring to Fig. 1 d.Comprise: laser 1, the first optical splitter 2 (can be the coupler A in diagram), MZI5, photodetector 7, the first controller 8, second controller 10, modulator 12, modulation source 11, coherent receiver 15, frequency mixer 17 and oscillator 16.
Described laser 1, for generation of laser;
Described the first optical splitter 2, for described laser is carried out to light splitting, obtain surveying light and control light;
Described MZI5, interfered the control light after being interfered for the described control light to input;
Described photodetector 7, carry out opto-electronic conversion for the control light by after described interference and obtain first signal of telecommunication;
Described the first controller 8, for according to described first signal of telecommunication, producing control signal, so that described MZI5 is controlled, 1/4th of the wavelength that the optical path difference that makes the light signal transmitted on two arms of described MZI5 is described laser;
Described modulator 12, for described detection light is modulated, generate detecting optical pulses;
Described modulation source 11, control 12 pairs of described detection light of described modulator for generation of modulator control signal and modulated;
Described coherent receiver 15, for receiving the light signal of returning from the down link transmission, and, to the processing that is concerned with of the described light signal that transmission is returned from down link, obtain second signal of telecommunication;
Described oscillator 16, for generation of electric local oscillation signal;
Described frequency mixer 17, for described electric local oscillation signal and described second signal of telecommunication are carried out to mixing, obtain baseband signal;
Described second controller 10, be used for according to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser, and based on the described degree of deviation, produce the frequency of control signal with the described electric local oscillation signal of controlling described oscillator 16 tuning its outputs, the practical center frequency of the described baseband signal that makes described frequency mixer 17 obtain converges on the standard value of the centre frequency of described laser.
The present embodiment can will be surveyed light by an optical splitter and be divided, the part marked off is surveyed to light and output to coherent receiver 15, described system also further comprises: the second optical splitter 4 (can be the coupler D in diagram), for from described detection light, separating a part of light, and be entered in described coherent receiver 15 and be concerned with the described light signal that transmission is returned from down link.
Mutual mechanism between each module of the device that optical fiber telecommunications system dynamic frequency offset in the present embodiment is corrected and function can, referring to the record of the corresponding embodiment of Fig. 1 a to Fig. 1 d, not repeat them here.
The present embodiment is divided into the laser scribing of laser output to survey light and control light, according to the control photometry, calculates and obtains the degree of deviation of the practical center frequency of laser with respect to the standard value of the centre frequency of laser; Carry out corresponding compensation according to this degree of deviation and control, to eliminate the impact that central frequency deviation was brought of laser, improve the optical coherent detection performance, and can reduce the requirement to the light source live width.
Finally it should be noted that: above embodiment only, in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment, the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: its technical scheme that still can put down in writing aforementioned each embodiment is modified, or part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.
Claims (9)
1. the method that a dynamic frequency offset is corrected, be applied in the impact that the frequency drift of eliminating laser in the Coherent optical time domain reflectometer system is brought, and it is characterized in that, comprising:
Laser to described laser output carries out light-splitting processing, generates and surveys light and control light;
Described control light is input in Mach-Zehnder interferometer MZI and is interfered, the control light after being interfered;
Control light after described interference is carried out to opto-electronic conversion, obtain first signal of telecommunication;
Be controlled at the optical path difference of the light signal transmitted on two arms of described MZI according to described first signal of telecommunication, make 1/4th of wavelength that described optical path difference is described laser;
According to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser;
According to the described degree of deviation, compensate accordingly, the practical center frequency of the baseband signal that makes the light signal of returning from downlink transmission obtain after receiving converges on the standard value of the centre frequency of described baseband signal.
2. method according to claim 1, it is characterized in that, according to the described degree of deviation, compensate accordingly, the practical center frequency of the baseband signal that makes the light signal of returning from downlink transmission obtain after receiving converges on the standard value of the centre frequency of described baseband signal, comprising:
The light signal from down link that described detection light and described Coherent optical time domain reflectometer system the are received processing that is concerned with, carry out opto-electronic conversion to the relevant light signal obtained of processing, and obtains second signal of telecommunication;
According to the described degree of deviation, control for described second signal of telecommunication, carrying out the frequency that mixing obtains the electric local oscillation signal of described baseband signal, make the practical center frequency of described baseband signal converge on the standard value of the centre frequency of described baseband signal.
3. method according to claim 1, it is characterized in that, according to the described degree of deviation, compensate accordingly, the practical center frequency of the baseband signal that makes the light signal of returning from downlink transmission obtain after receiving is positioned at the standard value of the centre frequency of described baseband signal, comprising:
Described detection light is being modulated while generating detecting optical pulses, controlled the output frequency of the modulation source for carrying out described modulation according to the described degree of deviation, making the centre frequency of described detecting optical pulses converge on the standard value of the centre frequency of described laser.
4. method according to claim 1, is characterized in that, the power of described detection light is greater than the power of described control light.
5. a Coherent optical time domain reflectometer system, is characterized in that, comprising: laser, the first optical splitter, Mach Zehnder interferometer MZI, photodetector, the first controller, second controller, modulator and modulation source;
Described laser, for generation of laser;
Described the first optical splitter, for described laser is carried out to light splitting, obtain surveying light and control light;
Described MZI, interfered the control light after being interfered for the described control light to input;
Described photodetector, carry out opto-electronic conversion for the control light by after described interference and obtain first signal of telecommunication;
Described the first controller, for according to described first signal of telecommunication, producing control signal, so that described MZI is controlled, 1/4th of the wavelength that the optical path difference that makes the light signal transmitted on two arms of described MZI is described laser;
Described modulator, for described detection light is modulated, generate detecting optical pulses;
Described modulation source, control described modulator for generation of modulator control signal described detection light modulated;
Described second controller, be used for according to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser, and based on the described degree of deviation, produce control signal and export the output frequency of described modulator control signal to control described modulation source, the practical center frequency of the described detecting optical pulses that makes described modulators modulate generate converges on the standard value of the centre frequency of described laser.
6. Coherent optical time domain reflectometer system according to claim 5, is characterized in that, described system also further comprises:
Coherent receiver, for receiving the light signal of returning from the down link transmission, and to the processing that is concerned with of the described light signal that transmission is returned from down link.
7. Coherent optical time domain reflectometer system according to claim 6, is characterized in that, described system also further comprises:
The second optical splitter, for from described detection light, separating a part of light, and be entered into described coherent receiver.
8. a Coherent optical time domain reflectometer system, it is characterized in that, described system comprises: laser, the first optical splitter, Mach Zehnder interferometer MZI, photodetector, the first controller, second controller, modulator, modulation source, coherent receiver, frequency mixer and oscillator;
Described laser, for generation of laser;
Described the first optical splitter, for described laser is carried out to light splitting, obtain surveying light and control light;
Described MZI, interfered the control light after being interfered for the described control light to input;
Described photodetector, carry out opto-electronic conversion for the control light by after described interference and obtain first signal of telecommunication;
Described the first controller, for according to described first signal of telecommunication, producing control signal, so that described MZI is controlled, 1/4th of the wavelength that the optical path difference that makes the light signal transmitted on two arms of described MZI is described laser;
Described modulator, for described detection light is modulated, generate detecting optical pulses;
Described modulation source, control described modulator for generation of modulator control signal described detection light modulated;
Described coherent receiver, for receiving the light signal of returning from the down link transmission, and, to the processing that is concerned with of the described light signal that transmission is returned from down link, obtain second signal of telecommunication;
Described oscillator, for generation of electric local oscillation signal;
Described frequency mixer, for described electric local oscillation signal and described second signal of telecommunication are carried out to mixing, obtain baseband signal;
Described second controller, be used for according to described first signal of telecommunication, calculate the degree of deviation of the practical center frequency of described laser with respect to the standard value of the centre frequency of described laser, and based on the described degree of deviation, produce the frequency of control signal with the described electric local oscillation signal of controlling described its output of oscillator tuning, the practical center frequency of the described baseband signal that makes described frequency mixer obtain converges on the standard value of the centre frequency of described laser.
9. Coherent optical time domain reflectometer system according to claim 8, is characterized in that, described system also further comprises:
The second optical splitter, for from described detection light, separating a part of light, and be entered in described coherent receiver with the described light signal that transmission is returned from down link and be concerned with.
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| CN201010601965.8A CN102170307B (en) | 2010-12-14 | 2010-12-14 | Dynamic frequency offset correction method and coherence optical time-domain reflectometer system |
| PCT/CN2011/083566 WO2012079480A1 (en) | 2010-12-14 | 2011-12-06 | Dynamic frequency deviation correction method and coherence optical time-domain reflectometer system |
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| CN102170307B (en) * | 2010-12-14 | 2014-01-08 | 华为技术有限公司 | Dynamic frequency offset correction method and coherence optical time-domain reflectometer system |
| CN104677398B (en) * | 2015-03-13 | 2017-03-15 | 南京大学 | A kind of Φ OTDR photosensitivity-enhancing methods and device based on frequency drift dynamic compensation |
| CN105699050B (en) * | 2016-02-04 | 2018-02-13 | 南京晓庄学院 | Merge the compound distributing optical fiber sensing method and system of chaos light source and coherent detection |
| CN106533547B (en) * | 2016-10-19 | 2018-12-18 | 全球能源互联网研究院有限公司 | Power optical fiber communication line fault monitoring device |
| WO2018232571A1 (en) * | 2017-06-19 | 2018-12-27 | 华为技术有限公司 | Uplink optical signal modulation method, optical communication node and system |
| CN110459937B (en) * | 2018-05-08 | 2021-03-23 | 华为技术有限公司 | Laser device |
| CN110492941B (en) | 2018-05-14 | 2021-01-29 | 华为技术有限公司 | Optical signal receiving and transmitting device |
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| CN101394232A (en) * | 2007-12-17 | 2009-03-25 | 北京邮电大学 | Device and method based on inserting and erasing of SOA-MZI optical cursor |
| CN101459638A (en) * | 2007-12-14 | 2009-06-17 | 华为技术有限公司 | Receiving apparatus and method for differential quadrature phased shift keying DQPSK signal |
| EP1723704B1 (en) * | 2004-03-02 | 2009-07-08 | Board of Trustees operating Michigan State University | Laser system using ultra-short laser pulses |
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| CN102170307B (en) * | 2010-12-14 | 2014-01-08 | 华为技术有限公司 | Dynamic frequency offset correction method and coherence optical time-domain reflectometer system |
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| EP1723704B1 (en) * | 2004-03-02 | 2009-07-08 | Board of Trustees operating Michigan State University | Laser system using ultra-short laser pulses |
| CN101459638A (en) * | 2007-12-14 | 2009-06-17 | 华为技术有限公司 | Receiving apparatus and method for differential quadrature phased shift keying DQPSK signal |
| CN101394232A (en) * | 2007-12-17 | 2009-03-25 | 北京邮电大学 | Device and method based on inserting and erasing of SOA-MZI optical cursor |
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