CN108964780A - Sender unit, signal receiver, system and method for the optical detection that is concerned with - Google Patents
Sender unit, signal receiver, system and method for the optical detection that is concerned with Download PDFInfo
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- CN108964780A CN108964780A CN201810833865.4A CN201810833865A CN108964780A CN 108964780 A CN108964780 A CN 108964780A CN 201810833865 A CN201810833865 A CN 201810833865A CN 108964780 A CN108964780 A CN 108964780A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/501—Structural aspects
- H04B10/503—Laser transmitters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/516—Details of coding or modulation
- H04B10/54—Intensity modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/61—Coherent receivers
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Abstract
The embodiment of the invention provides a kind of sender units, signal receiver, system and method for the optical detection that is concerned with.Concrete scheme is as follows: generating original carrier signal；According to default difference frequency, the frequency of original carrier signal is adjusted, and according to default modulating mode, by signal modulation to be detected into carrier signal adjusted, obtains the first signal.The first signal is received and amplified, second signal is obtained；The initial local oscillator optical signal generated is received, initial local oscillator optical signal is adjusted, second signal is coupled with local oscillator optical signal adjusted, then beat frequency processing is carried out to the signal after coupling, obtains third signal；Amplify third signal, and according to default demodulation modes, demodulates amplified third signal, the signal to be detected after being demodulated.Using scheme provided in an embodiment of the present invention, remote, highly sensitive transmission of the microwave signal in transmission link may be implemented, promote the overall performance of transmission link, meet actual demand.
Description
Technical field
The present invention relates to microwave signal field of detecting, more particularly to sender unit, the signal for the optical detection that is concerned with
Receiver, system and method.
Background technique
Microwave signal has important application in the modern life, in wireless communication, military radar, electronic warfare and ocean
The numerous areas such as detection have been widely used.
With the fast development of optical communication technique, for user to communication link rate and transmission range, receiver is sensitive
The demand of degree and channel communication capacity etc. is also higher and higher, and traditional optical communication technique can no longer meet practical need
It asks.Although current fibre loss has had reached a very low level with the promotion of optic fibre manufacturing technology, for
For very-long-range transmission, with being continuously increased for transmission range, the accumulated value of transmission loss will become larger, in practical application
In measured signal be frequently not it is very ideal, it is even fainter, especially underwater sound signal transmission detection.
Currently, during Underwater Detection, what is be widely used is direct detection system, the system during light amplification,
The noise signal of introducing is can not to eliminate, and noise signal can be built up with the increase of amplification link transmission range,
This signal-to-noise ratio that will result directly in entire link transmission signal deteriorates, the sensitivity decrease of channel, so that direct detection system
The overall performance of system is unable to satisfy actual demand.
Summary of the invention
The embodiment of the present invention be designed to provide it is a kind of for the sender unit for the optical detection that is concerned with, signal receiver,
System and method promotes the entirety of transmission link to realize remote, highly sensitive transmission of the microwave signal in transmission link
Performance meets actual demand.Specific technical solution is as follows:
The embodiment of the invention provides a kind of for the relevant sender unit for closing detection, the sender unit, including
Continuous wave laser, acousto-optic frequency shifters and intensity modulator；
The continuous wave laser, for generating stable first laser signal, as original carrier signal；
The acousto-optic frequency shifters, for the frequency of the original carrier signal being adjusted, after being adjusted according to default difference frequency
Carrier signal；
The intensity modulator is used for according to default modulating mode, by signal modulation to be detected to the load adjusted
In wave signal, the first signal is obtained；
The intensity modulator connects the first optical fiber, and first signal is transmitted by the first optical fiber.
The embodiment of the invention provides a kind of for the relevant signal receiver for closing detection, the signal receiver, including
Erbium-doped fiber amplifier, Polarization Controller, photo-coupler, balanced detector, low-noise amplifier and wave detector；
The erbium-doped fiber amplifier for receiving the first signal for passing through the first optical fiber and transmitting, and amplifies described first
Signal obtains second signal, wherein first signal is according to default modulating mode, by signal modulation to be detected to adjustment
Obtained in carrier signal afterwards, the carrier signal adjusted is to adjust the frequency of original carrier signal according to default difference frequency
What rate obtained, the original carrier signal is stable first laser signal；
The Polarization Controller, for receiving the initial local oscillator optical signal for passing through the second optical fiber and transmitting, and according to described the
Coherence and polarization state between binary signal and the initial local oscillator optical signal adjust the initial local oscillator optical signal, are adjusted
Local oscillator optical signal after whole, the initial local oscillator optical signal are stable second laser signal；
The photo-coupler is obtained for coupling the second signal with the local oscillator optical signal adjusted
Signal after coupling；
The balanced detector obtains third signal for carrying out beat frequency processing to the signal after the coupling；
The low-noise amplifier obtains amplified third signal for amplifying the third signal；
The wave detector, for the amplified third signal being demodulated, after being demodulated according to default demodulation modes
Signal to be detected.
Further, the signal receiver, further includes:
Optical filter, for being filtered respectively to the second signal and the local oscillator optical signal adjusted,
Obtain filtered second signal and filtered local oscillator optical signal；
The photo-coupler, be specifically used for will the filtered second signal and the filtered local oscillator optical signal into
Row coupling, the signal after being coupled.
Further, the signal receiver, further includes:
It matches electrical filter and obtains filtered third for being filtered to the amplified third signal
Signal；
The wave detector is specifically used for demodulating the filtered third signal according to default demodulation modes, being demodulated
Signal to be detected afterwards.
The embodiment of the invention also provides a kind of systems for the optical detection that is concerned with, including the first sender unit, second
Sender unit and signal receiver；
First sender unit, for generating stable first laser signal, as original carrier signal；According to pre-
If difference frequency, the frequency of the original carrier signal, the carrier signal after being adjusted are adjusted；It, will and according to default modulating mode
Signal modulation to be detected obtains the first signal into the carrier signal adjusted, passes through the first optical fiber transmission described first
Signal；
The second signal transmitter, as initial local oscillator optical signal, passes through for generating stable second laser signal
Second optical fiber transmits the initial local oscillator optical signal；
The signal receiver for receiving first signal for passing through first optical fiber and transmitting, and receives logical
Cross the initial local oscillator optical signal of the second optical fiber transmission；Amplify first signal, obtains second signal；According to described
Coherence and polarization state between second signal and the initial local oscillator optical signal adjust the initial local oscillator optical signal, obtain
Local oscillator optical signal adjusted；The second signal is coupled with the local oscillator optical signal adjusted, after obtaining coupling
Signal；Beat frequency processing is carried out to the signal after the coupling, obtains third signal；Amplify the third signal, is amplified
Third signal afterwards；According to default demodulation modes, the amplified third signal, the letter to be detected after being demodulated are demodulated
Number.
Further, the signal receiver is also used to obtaining the second signal and the local oscillator light adjusted
After signal, the second signal and the local oscillator optical signal adjusted are filtered respectively, obtain filtered
Binary signal and filtered local oscillator optical signal；
And it specifically for coupling the filtered second signal with the filtered local oscillator optical signal, obtains
Signal after to coupling.
Further, the signal receiver is also used to after obtaining the amplified third signal, to the amplification
Third signal afterwards is filtered, and obtains filtered third signal；
And be specifically used for demodulating the filtered third signal according to default demodulation modes, after being demodulated to
Detectable signal.
The embodiment of the invention also provides a kind of signaling methods of relevant optical detection, are applied to sender unit, institute
State method, comprising:
Stable first laser signal is generated, as original carrier signal；
According to default difference frequency, the frequency of the original carrier signal, the carrier signal after being adjusted are adjusted；
The first letter is obtained by signal modulation to be detected into the carrier signal adjusted according to default modulating mode
Number；
First signal is transmitted by the first optical fiber.
The embodiment of the invention also provides a kind of signal acceptance methods for the optical detection that is concerned with, and are applied to signal and receive
Device, the method, comprising:
The first signal transmitted by the first optical fiber is received, and amplifies first signal, obtains second signal, wherein
First signal be according to default modulating mode, by obtained in signal modulation to be detected to carrier signal adjusted, institute
Stating carrier signal adjusted is to obtain according to default difference frequency, the frequency of adjustment original carrier signal, the original carrier letter
Number be stable first laser signal；
The initial local oscillator optical signal transmitted by the second optical fiber is received, and according to the second signal and the initial local oscillator
Coherence and polarization state between optical signal, adjust the initial local oscillator optical signal, and the local oscillator optical signal after being adjusted is described
Initial local oscillator optical signal is stable second laser signal；
The second signal is coupled with the local oscillator optical signal adjusted, the signal after being coupled；
Beat frequency processing is carried out to the signal after the coupling, obtains third signal；
Amplify the third signal, obtains amplified third signal；
According to default demodulation modes, the amplified third signal, the signal to be detected after being demodulated are demodulated.
Further, the signal acceptance method, further includes:
After obtaining the second signal and the local oscillator optical signal adjusted, respectively to the second signal and described
Local oscillator optical signal adjusted is filtered, and obtains filtered second signal and filtered local oscillator optical signal；
It is described to couple the second signal with the local oscillator optical signal adjusted, the signal after being coupled,
Include:
The filtered second signal is coupled with the filtered local oscillator optical signal, the letter after being coupled
Number.
It is provided in an embodiment of the present invention a kind of for the sender unit for the optical detection that is concerned with, signal receiver, system and side
Method can produce stable first laser signal, as original carrier signal；According to default difference frequency, original carrier signal is adjusted
Frequency, the carrier signal after being adjusted；According to default modulating mode, signal modulation to be detected is believed to carrier wave adjusted
In number, the first signal is obtained；Transmit the first signal；The first signal transmitted by the first optical fiber is received, and amplifies the first signal,
Obtain second signal；The initial local oscillator optical signal transmitted by the second optical fiber is received, and according to second signal and initial local oscillator light
Coherence and polarization state between signal adjust initial local oscillator optical signal, the local oscillator optical signal after being adjusted；By second signal
It is coupled with local oscillator optical signal adjusted, the signal after being coupled；Beat frequency processing is carried out to the signal after coupling, is obtained
Third signal；Amplify third signal, obtains amplified third signal；According to default demodulation modes, amplified third is demodulated
Signal, the signal to be detected after being demodulated.The method provided through the embodiment of the present invention may be implemented microwave signal and transmit
Remote, highly sensitive transmission in link, promotes the overall performance of transmission link, meets actual demand.
Certainly, implement any of the products of the present invention or method it is not absolutely required at the same reach all the above excellent
Point.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
It obtains other drawings based on these drawings.
Fig. 1 is a kind of structural schematic diagram of the sender unit for the optical detection that is concerned with provided in an embodiment of the present invention；
Fig. 2 is a kind of structural schematic diagram of the signal receiver for the optical detection that is concerned with provided in an embodiment of the present invention；
Fig. 3 is a kind of laboratory simulation apparatus structure schematic diagram for the optical detection that is concerned with provided in an embodiment of the present invention；
Fig. 4 is the light pulse figure of the signal to be detected after coherent detection provided in an embodiment of the present invention demodulation；
Fig. 5 is the light pulse figure of the signal to be detected after non-coherent detection provided in an embodiment of the present invention demodulation；
Fig. 6 is coherent detection provided in an embodiment of the present invention and the output signal-to-noise ratio of non-coherent detection with input signal light function
The comparison diagram of rate variation；
Fig. 7 is a kind of structural schematic diagram of the system for the optical detection that is concerned with provided in an embodiment of the present invention；
Fig. 8 is a kind of signaling method flow chart for the optical detection that is concerned with provided in an embodiment of the present invention；
Fig. 9 is a kind of signal acceptance method flow chart for the optical detection that is concerned with provided in an embodiment of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
It is provided in an embodiment of the present invention a kind of for the sender unit for the optical detection that is concerned with, signal receiver, system and side
Method can produce stable first laser signal, as original carrier signal；According to default difference frequency, original carrier signal is adjusted
Frequency, the carrier signal after being adjusted；According to default modulating mode, signal modulation to be detected is believed to carrier wave adjusted
In number, the first signal is obtained；Transmit the first signal；The first signal transmitted by the first optical fiber is received, and amplifies the first signal,
Obtain second signal；The initial local oscillator optical signal transmitted by the second optical fiber is received, and according to second signal and initial local oscillator light
Coherence and polarization state between signal adjust initial local oscillator optical signal, the local oscillator optical signal after being adjusted；By second signal
It is coupled with local oscillator optical signal adjusted, the signal after being coupled；Beat frequency processing is carried out to the signal after coupling, is obtained
Third signal；Amplify third signal, obtains amplified third signal；According to default demodulation modes, amplified third is demodulated
Signal, the signal to be detected after being demodulated.The method provided through the embodiment of the present invention may be implemented microwave signal and transmit
Remote, highly sensitive transmission in link, promotes the overall performance of transmission link, meets actual demand.
The embodiment of the invention provides a kind of signal receivers for the optical detection that is concerned with, as shown in Figure 1, may include connecting
Continuous laser 101, acousto-optic frequency shifters 102 and intensity modulator 103.
Continuous wave laser 101, for generating stable first laser signal, as original carrier signal.
Specifically, stable first laser signal can be generated using continuous wave lasers such as narrow linewidth lasers, as first
Beginning carrier signal.
Assuming that original carrier signal f1(t) it is expressed asWherein, A1Indicate amplitude,
w1Indicate angular frequency,Indicate initial phase.And w1=2 π f1, f1Indicate the frequency of original carrier signal.Due to original carrier signal
For laser signal, therefore, the frequency of signal is often the high-frequency signal of THz rank.
Acousto-optic frequency shifters 102, for adjusting the frequency of original carrier signal, the load after being adjusted according to default difference frequency
Wave signal.
Specifically, can realize original carrier using acousto-optic modulator (Acousto-optics Modulators, AOM)
The difference frequency of signal adjusts.
For example, the original carrier signal for using specification to generate for the AOM of 100MHz to continuous wave laser 101 is handled,
The frequency of carrier signal after being adjusted will be by f1It is adjusted to f1+100MHz。
Intensity modulator 103 is used for according to default modulating mode, by signal modulation to be detected to carrier signal adjusted
In, obtain the first signal.
Specifically, Mach-Zehnder modulators (Mach-Zehnder modulator, MZM) can be used, according to carrier wave
Inhibit double sideband modulation mode, new number to be detected is modulated in the carrier signal adjusted of acousto-optic frequency shifters 102, obtains first
Signal.
Further, it in order to improve the noise inhibiting ability of signal power, can also be modulated using carrier-suppressed SSB
Mode obtains the first signal by signal modulation to be detected into the carrier signal adjusted of acousto-optic frequency shifters 102.In addition to this,
The amplitude that belongs to of above-mentioned either Double Sideband Suppressed Carrier modulating mode or carrier-suppressed SSB modulating mode all is modulated,
Its amplitude of the first signal namely obtained is converted according to the amplitude of signal to be detected, but its frequency keeps carrier wave adjusted
The frequency of signal.
In embodiments of the present invention, above-mentioned signal to be detected can be is obtained from specific environment using other equipment
The signal arrived.For example, some signal obtained from ocean using detectoscope etc..It is just not especially limited herein.It removes
Other than this, since signal to be detected is the signal obtained from specific environment, due to its cannot by optical fiber, antenna etc. directly into
The remote transmission of row, otherwise will cause the frequency of signal, bandwidth etc. is interfered, to cause distorted signals.Therefore, it is necessary to will
Signal modulation to be detected is into high-frequency signal, then is transmitted.
Intensity modulator 103 connects the first optical fiber, and the first signal is transmitted by the first optical fiber.
Specifically, connect using long optical fibers with intensity modulator 103, the first signal transmitted by long optical fibers, from
And realize the remote transmission to the first signal.
In embodiments of the present invention, due to above-mentioned original carrier signal, carrier signal adjusted and the first signal its
Matter is still optical signal, and therefore, the laser signal that above-mentioned continuous wave laser is generated is sent into optical fiber, and above-mentioned using optical fiber connection
Acousto-optic frequency shifters and intensity modulator using the total reflection of light, realize the transmission of optical signal in a fiber.
The embodiment of the invention also provides a kind of signal receivers for coherent light, as shown in Fig. 2, including Er-doped fiber
Amplifier 201, Polarization Controller 202, photo-coupler 203, balanced detector 204, low-noise amplifier 205 and wave detector 206.
Erbium-doped fiber amplifier 201 for receiving the first signal for passing through the first optical fiber and transmitting, and amplifies the first signal,
Obtain second signal, wherein the first signal is to believe signal modulation to be detected to carrier wave adjusted according to default modulating mode
Obtained in number, carrier signal adjusted is to adjust the frequency of original carrier signal according to default difference frequency to obtain, and initial
Carrier signal is stable first laser signal.
Specifically, the other end connection Er-doped fiber of the first optical fiber connected in above-mentioned signal receiver intensity modulator
Amplifier 201, the first signal generated for receiving above-mentioned signal receiver, and signal function is carried out to the first signal received
Rate amplification, obtains second signal.
Polarization Controller 202, for receiving the initial local oscillator optical signal for passing through the second optical fiber and transmitting, and according to second signal
Coherence and polarization state between initial local oscillator optical signal, adjust initial local oscillator optical signal, the local oscillator light letter after being adjusted
Number, initial local oscillator optical signal is stable second laser signal.
Specifically, using with identical continuous wave laser in above-mentioned signal receiver, e.g., narrow linewidth laser, generate with
The identical stable second laser signal of first laser signal, as initial local oscillator optical signal.Using Polarization Controller, according to upper
Amplitude, phase, frequency and the direction of vibration etc. for stating second signal, are adjusted initial local oscillator optical signal, after being adjusted
Local oscillator optical signal guarantees coherence and polarization state between second signal and local oscillator light adjusted.
Further, the default difference frequency between the initial local oscillator optical signal of guarantee and above-mentioned original carrier signal, Ke Yi
Acousto-optic frequency shifters are set in above-mentioned sender unit, and similarly, above-mentioned acousto-optic frequency shifters can also obtain initial local oscillator optical signal
Later, the frequency of initial local oscillator light is adjusted according to default difference frequency using acousto-optic frequency shifters.
It can be seen from the above, in embodiments of the present invention, original carrier signal is using complete phase with initial local oscillator optical signal
The same laser signal that same continuous wave laser generates, to guarantee that original carrier signal and initial local oscillator optical signal are frequency phases
The same and identical coherent light of direction of vibration.
Photo-coupler 203, for second signal to be coupled with local oscillator optical signal adjusted, the letter after being coupled
Number.
Specifically, three-dB coupler can be used, second signal and local oscillator optical signal adjusted are coupled, obtained
Signal after coupling.
Balanced detector 204 obtains third signal for carrying out beat frequency processing to the signal after coupling.
Specifically, can use balanced detector, the signal obtained after 203 coupling processing of photo-coupler is carried out at beat frequency
Reason, obtains third signal, so that the centre frequency of third signal is IF frequency.
Further, during above-mentioned erbium-doped fiber amplifier 201 carries out power amplification to received first signal, no
It is evitable to introduce amplified spontaneous emission noise (Amplifier Spontaneous Emission Noise, ASE noise),
Obtain second signal, it is assumed that second signal indicates at this time are as follows:
X (t)=s (t)+n (t)
Wherein, x (t) indicates second signal, and s (t) indicates that amplified first signal, n (t) indicate the noise introduced letter
Number, t indicates the time.
So, it is assumed that local oscillator optical signal adjusted is expressed as y (t), then by 3dB photo-coupler, treated obtains
Signal after coupling, and the signal that be balanced in detector two photodiodes receive is respectively by the signal after couplingWithThe optical power of signal is respectively as follows: at this time
Wherein, x (t) indicates second signal, and y (t) indicates local oscillator optical signal adjusted, and Re expression takes real part, and * is indicated altogether
Yoke, t indicate the time.
Common-mode signal is able to suppress due to balanced detector, the optical power of third signal is expressed as 2Re (x (t)
y*(t)).Because in second signal x (t) including ASE noise signal, according to the output result of balanced detector it is found that
The bat noise of the bat noise of ASE noise and ASE noise, ASE and second signal can be inhibited, at this point, in third signal
It only include the bat noise of ASE noise and local oscillator optical signal adjusted.Therefore, most of noise signal is effectively suppressed.
In embodiments of the present invention, balanced detector substantially belongs to a kind of photodetector, but in actual use process
In, the type of photodetector includes in very much, for example, single-ended detector and coherence detector etc., it is contemplated that receiving
The overall performance of device has selected balanced detector.But the embodiment of the present invention can equally use other kinds of photodetection
Device can specifically select according to the actual situation, for example, when transmission range is relatively free of especially far, to inhibition noise immune requirement
When not high and structure is relatively easy, can using single-ended detector or transmission range farther out and signal detection it is accurate
When spending more demanding, coherence detector can be used.
Low-noise amplifier 205 obtains amplified third signal for amplifying third signal.
Specifically, amplifying using power of the low-noise amplifier to third signal, amplified signal is obtained, because
The noise coefficient of low-noise amplifier is relatively low, so the noise that amplified third signal introduces is relatively low, effectively
The influence for avoiding noise signal.
In embodiments of the present invention, above-mentioned balanced detector 204 main function on the one hand be to the signal after coupling into
Row is patted frequency and is handled；It on the other hand is exactly to carry out photoelectric conversion, it can be seen from the above, initial local oscillator optical signal, local oscillator adjusted
Optical signal and second signal are optical signals, and the signal that photo-coupler 203 is handled after obtained coupling is still optical signal,
Therefore, the third signal that signal after coupling obtains after the processing of balanced detector 204 will be electric signal, then balance detection
Connection between device 204 and photo-coupler 203, and connection before this are connected by optical fiber, and balance detection
Connection between device 204 and low-noise amplifier 205 is connected using the transfer wire of cable.
Wave detector 206 demodulates amplified third signal for according to default demodulation modes, after being demodulated wait visit
Survey signal.
Specifically, envelope detector can be used, envelope detection is carried out to amplified third signal, after being demodulated
Signal to be detected.
Further, the demodulation mode of above-mentioned amplified third signal can also be adopted other than envelope detection
With demodulation modes such as coherent demodulations.
In the embodiment of above-mentioned signal receiver, above-mentioned erbium-doped fiber amplifier 201 is being utilized, is receiving and passes through the first light
First signal of fibre transmission, and amplify the first signal, after obtaining second signal, optical filter can be used, to second signal
It is filtered, obtains filtered second signal.
Similarly, above-mentioned Polarization Controller 202 is being utilized, is receiving the initial local oscillator optical signal transmitted by the second optical fiber, and
According between second signal and initial local oscillator optical signal coherence and polarization state, adjust initial local oscillator optical signal, be adjusted
After local oscillator optical signal afterwards, optical filter can also be used, local oscillator optical signal adjusted is filtered, is filtered
Local oscillator optical signal after wave.
Later, photo-coupler 203 is being utilized, filtered second signal and filtered local oscillator optical signal is subjected to coupling
It closes, the signal after being coupled.
It can be seen from the above, photo-coupler can be used, above-mentioned second signal and local oscillator optical signal adjusted are filtered
Wave processing, so that the system noise in second signal and local oscillator optical signal adjusted is inhibited, certainly, due to initial sheet
The optical signal that shakes handles relatively easy, the noise signal of introducing during local oscillator optical signal adjusted from generating to being adjusted to
Relatively fewer, therefore, local oscillator optical signal adjusted can not also be into the processing for crossing optical filter.
In the embodiment of above-mentioned signal receiver, above-mentioned low-noise amplifier 205 is being utilized, is amplifying third signal, obtains
To after amplified third signal, can be filtered using matching electrical filter to amplified third signal,
Obtain filtered third signal.
Later, filtered third signal is demodulated, is demodulated according to default demodulation modes using above-mentioned wave detector 206
Signal to be detected afterwards.
It can be seen from the above, can be filtered, obtain to above-mentioned amplified third signal using matching electrical filter
To filtered third signal, at this point, the ratio of the instantaneous power and noise signal mean power of filtered third signal reaches
There is maximum signal to noise ratio to maximum, that is, filtered third signal, effectively inhibit in amplified third signal
Noise signal, be conducive to the later period demodulated after signal to be detected.
In embodiments of the present invention, since sender unit and signal receiver are used in practical application scene
, in order to preferably embody the specific effect of above-mentioned sender unit and signal receiver in embodiments of the present invention, now provide
A kind of laboratory simulation device for related optical detection, as shown in figure 3, specific embodiment can be with are as follows:
Using narrow linewidth laser, generating a branch of wavelength is 1550nm, and frequency is the laser signal of 193.3THz, this is swashed
Optical signal is divided into the laser signal of two identical frequencies by photo-coupler, and a laser signal is as original carrier signal, separately
One laser signal is as initial local oscillator optical signal, wherein original carrier signal entering signal optical path is transmitted, initial local oscillator
Optical signal is transmitted in local oscillator optical path.
In signal optical path, shift frequency processing is carried out to original carrier signal using the AOM of specification 100MHz, after being adjusted
Carrier signal meet the item of heterodyne detection so that carrier signal adjusted and initial local oscillator optical signal have default difference frequency
Part.Later, the small-signal that kHz rank is generated using microwave signal source, is pressed down using MZM according to carrier wave as signal to be detected
Double sideband modulation mode processed, by signal modulation to be detected into carrier signal adjusted, using modulated signal as first
Signal.The optical power of the first signal, mould are adjusted using VOA (Variable Optical Attenuator, variable optical attenuator)
Quasi- first signal is during actual transmissions, with the increase of transmission range, the decaying of signal light power.Utilize EDFA
(Erbium-doped Optical Fiber Amplifier, erbium-doped fiber amplifier), amplifies processing to the first signal,
Obtain second signal.
In local oscillator optical path, using Polarization Controller, according to the coherence between second signal and initial local oscillator optical signal
And polarization state, initial local oscillator optical signal is adjusted, the local oscillator optical signal after being adjusted.
Later, using three-dB coupler, above-mentioned second signal and local oscillator optical signal adjusted is coupled, coupling is obtained
Signal after conjunction.It carries out beat frequency to the signal after coupling using balanced detector to handle to obtain third signal, by balance detection
Device is handled, and the ASE noise in the signal after coupling is effectively suppressed, meanwhile, the signal after coupling switchs to telecommunications by optical signal
Number.Processing is amplified to third signal using low-noise amplifier, obtains amplified third signal.Using envelope detection,
Demodulation process is carried out to amplified third signal, the signal to be detected after being demodulated.
Using frequency spectrograph, acquisition uses the light pulse figure of the signal to be detected after the demodulation of above-mentioned coherent detection, such as Fig. 4 institute
To show, and under the same conditions, acquisition uses the light pulse figure of the signal to be detected after non-coherent detection demodulation, as shown in figure 5,
Two light pulse figures are compared, it can be clearly seen that, what coherent detection obtained after demodulating compared to non-coherent detection
The bottom of making an uproar of signal is obviously greatly lowered.
Specifically, signal is made an uproar, the unit at bottom is dBm/Hz, can indicate power spectral density.Power spectral density pair when calculating
Frequency integrator can obtain the signal power in integral frequency range.And general power (dBm)=power spectral density+10logBW. is wherein,
BW indicates the bandwidth of integral frequency range.By Fig. 4 and Fig. 5 it is found that the size at bottom of making an uproar can be expressed as in addition to signal to be detected in figure
The average value size of flat, it can clearly be seen that coherent detection is more much lower than non-coherent detection, therefore, coherent detection is made an uproar
Bottom is lower than the bottom of making an uproar of non-coherent detection, more preferable to the inhibitory effect of noise.
In addition to this, the output signal-to-noise ratio and above-mentioned letter in the embodiment of the present invention also to coherent detection and non-coherent detection
Number receiver front end input optical power compares, that is, compares the signal to be detected after demodulation and above-mentioned first signal
The comparison of signal light power.As shown in fig. 6, two curves respectively represent the knot of coherent detection and non-coherent detection comparison in figure
Fruit, in above-mentioned signal receiver front end, if its input power is -47dBm, the signal-to-noise ratio of coherent link improves 10dB, and
And judged according to curvilinear trend, as input signal light power reduces, that is, when signal to be detected is transmitted at a distance, with
Being continuously increased for transmission range, the signal-to-noise ratio advantage of coherent demodulation link also will constantly increase, this meaning whole system in length
Sensitivity in Distance Transmission demodulating process will be higher.
In embodiments of the present invention, due to being limited by laboratory device, above-mentioned experimental data is relatively guarded, but
Be it can be seen from the above, using the embodiment of the present invention, compared with prior art, the noise in remote transmission process of small-signal
Than that will be greatly enhanced, while the sensitivity for demodulating link will be promoted, and microwave signal may be implemented in transmission link
Remote, highly sensitive transmission, promote the overall performance of transmission link, meet actual demand.
Based on same inventive concept, sent out in a kind of signal for the optical detection that is concerned with that the embodiments of the present invention provide
On the basis of sending device and signal receiver, the embodiment of the invention provides a kind of systems for the optical detection that is concerned with, such as Fig. 7 institute
Show, may include the first sender unit 701, second signal transmitter 702 and signal receiver 703.
First sender unit 701, for generating stable first laser signal, as original carrier signal；According to pre-
If difference frequency, the frequency of original carrier signal, the carrier signal after being adjusted are adjusted；It, will be wait visit and according to default modulating mode
Signal modulation is surveyed into carrier signal adjusted, obtains the first signal, the first signal is transmitted by the first optical fiber.
Second signal transmitter 702, as initial local oscillator optical signal, passes through for generating stable second laser signal
Second optical fiber transmits initial local oscillator optical signal.
Signal receiver 703, for receive pass through the first optical fiber transmit the first signal, and receive pass through the second optical fiber
The initial local oscillator optical signal of transmission；Amplify the first signal, obtains second signal；According to second signal and initial local oscillator optical signal it
Between coherence and polarization state, adjust initial local oscillator optical signal, the local oscillator optical signal after being adjusted；By second signal and adjustment
Local oscillator optical signal afterwards is coupled, the signal after being coupled；Beat frequency processing is carried out to the signal after coupling, obtains third letter
Number；Amplify third signal, obtains amplified third signal；According to default demodulation modes, amplified third signal is demodulated, is obtained
Signal to be detected after to demodulation.
Further, above-mentioned signal receiver 703 is also used to obtaining second signal and local oscillator optical signal adjusted
Afterwards, second signal and local oscillator optical signal adjusted are filtered respectively, obtain filtered second signal and filtering
Local oscillator optical signal afterwards.
And specifically for coupling filtered second signal with filtered local oscillator optical signal, after obtaining coupling
Signal.
Further, above-mentioned signal receiver 703 is also used to after obtaining amplified third signal, to amplified
Third signal is filtered, and obtains filtered third signal.
And be specifically used for demodulating filtered third signal according to default demodulation modes, it is to be detected after being demodulated
Signal.
Based on same inventive concept, sent out in a kind of signal for the optical detection that is concerned with that the embodiments of the present invention provide
On the basis of sending device, the embodiment of the invention also provides a kind of signaling methods for coherent light, are applied to above-mentioned signal
Transmitter, as shown in figure 8, may comprise steps of:
Step S801 generates stable first laser signal, as original carrier signal.
Step S802 adjusts the frequency of original carrier signal, the carrier signal after being adjusted according to default difference frequency.
Step S803 by signal modulation to be detected into carrier signal adjusted, obtains according to default modulating mode
One signal.
Step S804 transmits the first signal by the first optical fiber.
Based on same inventive concept, connect in a kind of signal for the optical detection that is concerned with that the embodiments of the present invention provide
On the basis of receiving device, the embodiment of the invention also provides a kind of signal acceptance methods for the optical detection that is concerned with, and are applied to above-mentioned
Signal receiver, as shown in figure 9, may comprise steps of:
Step S901 receives the first signal transmitted by the first optical fiber, and amplifies the first signal, obtains second signal.
Wherein, the first signal is, by obtained in signal modulation to be detected to carrier signal adjusted, to adjust according to default modulating mode
Carrier signal after whole is to obtain according to default difference frequency, the frequency of adjustment original carrier signal, and original carrier signal is to stablize
First laser signal.
Step S902, receives the initial local oscillator optical signal transmitted by the second optical fiber, and according to second signal and it is initial this
Coherence and polarization state between vibration optical signal, adjust initial local oscillator optical signal, the local oscillator optical signal after being adjusted.Wherein,
Initial local oscillator optical signal can be as stable second laser signal.
Step S903 couples second signal with local oscillator optical signal adjusted, the signal after being coupled.
Step S904 carries out beat frequency processing to the signal after coupling, obtains third signal.
Step S905 amplifies third signal, obtains amplified third signal.
Step S906 demodulates amplified third signal, the letter to be detected after being demodulated according to default demodulation modes
Number.
Further, after obtaining second signal and local oscillator optical signal adjusted, respectively to second signal and after adjusting
Local oscillator optical signal be filtered, obtain filtered second signal and filtered local oscillator optical signal.
Second signal is coupled with local oscillator optical signal adjusted, the signal after being coupled, comprising:
Filtered second signal is coupled with filtered local oscillator optical signal, the signal after being coupled.
Further, after obtaining amplified third signal, third signal is filtered, after obtaining filtering
Third signal.
According to default demodulation modes, amplified third signal, the signal to be detected after being demodulated are demodulated, comprising:
According to default demodulation modes, filtered third signal, the signal to be detected after being demodulated are demodulated.
In embodiments of the present invention, above-mentioned a kind of to be connect for the system for the optical detection that is concerned with, signaling method and signal
In receiving method, processing apparatus used by the processing to unlike signal can refer to a kind of above-mentioned letter for the optical detection that is concerned with
The device used in number transmitter and signal receiver completes the process flow to above-mentioned unlike signal.
It should be noted that, in this document, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to
Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those
Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or equipment
Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that
There is also other identical elements in process, method, article or equipment including the element.
Each embodiment in this specification is all made of relevant mode and describes, same and similar portion between each embodiment
Dividing may refer to each other, and each embodiment focuses on the differences from other embodiments.Especially for system and
For embodiment of the method, since it is substantially similar to sender unit and signal receiver embodiment, so the comparison of description is simple
Single, the relevent part can refer to the partial explaination of embodiments of method.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the scope of the present invention.It is all
Any modification, equivalent replacement, improvement and so within the spirit and principles in the present invention, are all contained in protection scope of the present invention
It is interior.
Claims (10)
1. a kind of sender unit for the optical detection that is concerned with, which is characterized in that including continuous wave laser, acousto-optic frequency shifters and strong
Spend modulator；
The continuous wave laser, for generating stable first laser signal, as original carrier signal；
The acousto-optic frequency shifters, for adjusting the frequency of the original carrier signal, the load after being adjusted according to default difference frequency
Wave signal；
The intensity modulator, for according to default modulating mode, signal modulation to be detected to be believed to the carrier wave adjusted
In number, the first signal is obtained；
The intensity modulator connects the first optical fiber, and first signal is transmitted by the first optical fiber.
2. a kind of signal receiver for the optical detection that is concerned with, which is characterized in that including erbium-doped fiber amplifier, Polarization Control
Device, photo-coupler, balanced detector, low-noise amplifier and wave detector；
The erbium-doped fiber amplifier for receiving the first signal for passing through the first optical fiber and transmitting, and amplifies first signal,
Obtain second signal, wherein first signal is according to default modulating mode, by signal modulation to be detected to load adjusted
Obtained in wave signal, the carrier signal adjusted is according to default difference frequency, and the frequency for adjusting original carrier signal obtains
, the original carrier signal is stable first laser signal；
The Polarization Controller, for receiving the initial local oscillator optical signal for passing through the second optical fiber and transmitting, and according to second letter
Coherence and polarization state number between the initial local oscillator optical signal, adjust the initial local oscillator optical signal, after being adjusted
Local oscillator optical signal, the initial local oscillator optical signal be stable second laser signal；
The photo-coupler is coupled for coupling the second signal with the local oscillator optical signal adjusted
Signal afterwards；
The balanced detector obtains third signal for carrying out beat frequency processing to the signal after the coupling；
The low-noise amplifier obtains amplified third signal for amplifying the third signal；
The wave detector, for demodulating the amplified third signal according to default demodulation modes, after being demodulated wait visit
Survey signal.
3. signal receiver according to claim 2, which is characterized in that further include:
Optical filter is obtained for being filtered respectively to the second signal and the local oscillator optical signal adjusted
Filtered second signal and filtered local oscillator optical signal；
The photo-coupler is specifically used for the filtered second signal and the filtered local oscillator optical signal carrying out coupling
It closes, the signal after being coupled.
4. signal receiver according to claim 2 or 3, which is characterized in that further include:
It matches electrical filter and obtains filtered third signal for being filtered to the amplified third signal；
The wave detector is specifically used for the filtered third signal being demodulated, after being demodulated according to default demodulation modes
Signal to be detected.
5. a kind of system for the optical detection that is concerned with, which is characterized in that including the first sender unit, second signal transmitter and
Signal receiver；
First sender unit, for generating stable first laser signal, as original carrier signal；According to default difference
Frequently, the frequency of the original carrier signal, the carrier signal after being adjusted are adjusted；It, will be wait visit and according to default modulating mode
Signal modulation is surveyed into the carrier signal adjusted, obtains the first signal, first signal is transmitted by the first optical fiber；
The second signal transmitter, as initial local oscillator optical signal, passes through second for generating stable second laser signal
Optical fiber transmits the initial local oscillator optical signal；
The signal receiver, for receive pass through first optical fiber transmit first signal, and receive pass through institute
State the initial local oscillator optical signal of the second optical fiber transmission；Amplify first signal, obtains second signal；According to described second
Coherence and polarization state between signal and the initial local oscillator optical signal adjust the initial local oscillator optical signal, are adjusted
Local oscillator optical signal afterwards；The second signal is coupled with the local oscillator optical signal adjusted, the letter after being coupled
Number；Beat frequency processing is carried out to the signal after the coupling, obtains third signal；Amplify the third signal, obtains amplified
Third signal；According to default demodulation modes, the amplified third signal, the signal to be detected after being demodulated are demodulated.
6. system according to claim 5, which is characterized in that the signal receiver is also used to obtaining described second
After signal and the local oscillator optical signal adjusted, the second signal and the local oscillator optical signal adjusted are carried out respectively
Filtering processing, obtains filtered second signal and filtered local oscillator optical signal；
And specifically for coupling the filtered second signal with the filtered local oscillator optical signal, obtain coupling
Signal after conjunction.
7. system according to claim 5 or 6, which is characterized in that the signal receiver is also used to obtaining described put
After third signal after big, the amplified third signal is filtered, filtered third signal is obtained；
And be specifically used for demodulating the filtered third signal according to default demodulation modes, it is to be detected after being demodulated
Signal.
8. a kind of signaling method for the optical detection that is concerned with is applied to sender unit characterized by comprising
Stable first laser signal is generated, as original carrier signal；
According to default difference frequency, the frequency of the original carrier signal, the carrier signal after being adjusted are adjusted；
The first signal is obtained by signal modulation to be detected into the carrier signal adjusted according to default modulating mode；
First signal is transmitted by the first optical fiber.
9. a kind of signal acceptance method for the optical detection that is concerned with is applied to signal receiver characterized by comprising
The first signal transmitted by the first optical fiber is received, and amplifies first signal, obtains second signal, wherein described
First signal be according to default modulating mode, by obtained in signal modulation to be detected to carrier signal adjusted, the tune
Carrier signal after whole is to obtain according to default difference frequency, the frequency of adjustment original carrier signal, and the original carrier signal is
Stable first laser signal；
The initial local oscillator optical signal transmitted by the second optical fiber is received, and is believed according to the second signal and the initial local oscillator light
Coherence and polarization state between number, adjust the initial local oscillator optical signal, and the local oscillator optical signal after being adjusted is described initial
Local oscillator optical signal is stable second laser signal；
The second signal is coupled with the local oscillator optical signal adjusted, the signal after being coupled；
Beat frequency processing is carried out to the signal after the coupling, obtains third signal；
Amplify the third signal, obtains amplified third signal；
According to default demodulation modes, the amplified third signal, the signal to be detected after being demodulated are demodulated.
10. signal acceptance method according to claim 9, which is characterized in that further include:
After obtaining the second signal and the local oscillator optical signal adjusted, respectively to the second signal and the adjustment
Local oscillator optical signal afterwards is filtered, and obtains filtered second signal and filtered local oscillator optical signal；
It is described to couple the second signal with the local oscillator optical signal adjusted, the signal after being coupled, comprising:
The filtered second signal is coupled with the filtered local oscillator optical signal, the signal after being coupled.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5060311A (en) * | 1989-06-06 | 1991-10-22 | Siemens Aktiengesellschaft | Method and apparatus for obtaining phase or polarization insensitive optical heterodyne reception for dpsk or ask-modulated transmission signal |
| CN101551517A (en) * | 2009-05-11 | 2009-10-07 | 长春理工大学 | Coherent laser communication system based on wavefront correction |
| CN103051375B (en) * | 2012-11-15 | 2015-08-26 | 西安理工大学 | Wireless laser communication heterodyne detection system and detection method thereof |
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2018
- 2018-07-26 CN CN201810833865.4A patent/CN108964780A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5060311A (en) * | 1989-06-06 | 1991-10-22 | Siemens Aktiengesellschaft | Method and apparatus for obtaining phase or polarization insensitive optical heterodyne reception for dpsk or ask-modulated transmission signal |
| CN101551517A (en) * | 2009-05-11 | 2009-10-07 | 长春理工大学 | Coherent laser communication system based on wavefront correction |
| CN103051375B (en) * | 2012-11-15 | 2015-08-26 | 西安理工大学 | Wireless laser communication heterodyne detection system and detection method thereof |
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