CN105790840B - Broadband analog signal linearizes fibre-optic transmission system (FOTS) - Google Patents
Broadband analog signal linearizes fibre-optic transmission system (FOTS) Download PDFInfo
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- CN105790840B CN105790840B CN201610319712.9A CN201610319712A CN105790840B CN 105790840 B CN105790840 B CN 105790840B CN 201610319712 A CN201610319712 A CN 201610319712A CN 105790840 B CN105790840 B CN 105790840B
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- Prior art keywords
- signal
- electro
- optic
- intensity modulator
- optic intensity
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Classifications
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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
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
- H04B10/2543—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to fibre non-linearities, e.g. Kerr effect
-
- 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
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2575—Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
Abstract
The present invention provides a kind of broadband analog signal linearisation fibre-optic transmission system (FOTS), including analog radio-frequency signal source, for sending analog radio-frequency signal；Power divider, for analog radio-frequency signal to be divided into two-way, it is loaded into respectively on two electro-optic intensity modulators and is used as modulated signal；Analog radio-frequency signal delayer, for entering line delay to analog radio-frequency signal；First light source, secondary light source, for producing carrier wave optical signal；Single output electro-optic intensity modulator, for carrying out electro-optic intensity modulation to the modulated signal of transmission；Wavelength division multiplexer, for receiving two ways of optical signals, and it is output on dual output electro-optic intensity modulator and is used as carrier signal；Dual output electro-optic intensity modulator, for carrying out electro-optic intensity modulation to the modulated signal of transmission；Photodetector is balanced, for receiving the modulated optical signal of dual output electro-optic intensity modulator respectively, and is converted into corresponding electric signal.The present invention can improve the shortcomings that prior art non-linear distortion is larger.
Description
Technical field
The present invention relates to technical field of optical fiber communication, specifically broadband analog signal linearisation fibre-optic transmission system (FOTS).
Background technology
Fiber optic communication is one of current development high-tech area the most rapid, have message capacity is big, transmission quality is high,
Good confidentiality, electromagnetism interference, radioresistance, small volume, it is in light weight the advantages that, be current information transfer principal mode.
In traditional analog signal optical fiber telecommunications system, existing modulation system is mainly based upon the intensity of single-stage modulator
Modulation.Because traditional intensity modulated mode has the obvious mutual intermodulation distortion of three ranks, cause the signal of optical fiber telecommunications system non-
Linear distortion is larger.
Therefore, in order to improve the signal caused by the mutual intermodulation distortion of three ranks in traditional optical modulator transmission it is non-
Linear effect, realize that a kind of broadband linear fibre-optic transmission system (FOTS) of analog signal is very necessary.
The content of the invention
For existing conventional analog signal optical fiber transmission technique non-linear distortion it is larger the shortcomings that, the present invention provides a kind of
Broadband analog signal linearizes fibre-optic transmission system (FOTS), for improving above mentioned problem.
To achieve these goals and other related purposes, the present invention adopt the following technical scheme that：
A kind of broadband analog signal linearizes fibre-optic transmission system (FOTS), including：Analog radio-frequency signal source, power divider, mould
Intend radiofrequency signal delayer, the first light source, secondary light source, single output electro-optic intensity modulator, wavelength division multiplexer, dual output electric light
Intensity modulator, balance photodetector；The analog radio-frequency signal source produces analog radio-frequency signal, is transferred to power distribution
Device；Analog radio-frequency signal is respectively outputted to single output electro-optic intensity modulator and analog radio-frequency signal and prolonged by the power divider
When device；The signal that power divider is sent is entered the analog radio-frequency signal delayer into line delay and to send dual output electric light strong
Modulator is spent as modulated signal；First light source using caused optical signal transmission to single output electro-optic intensity modulator as
Carrier signal；The secondary light source is by caused optical signal transmission to wavelength division multiplexer；Single output electro-optic intensity modulator
For being modulated to optical signal, and modulated signal is output to wavelength division multiplexer；The wavelength division multiplexer will pass through single output
The optical signal that optical signal and secondary light source after electro-optic intensity modulator modulation are sent, dual output electricity is transferred to after power combing
Light intensity modulator；The dual output electro-optic intensity modulator, receive the analog radio frequency letter that analog radio-frequency signal delayer is sent
Number optical signal sent to wavelength division multiplexer as modulated signal carries out intensity modulation, and its both ends output optical signal difference is defeated
Go out to balance photodetector.
Further, first light source and secondary light source produce (carrier wave) optical signal of high stability by laser.
Further, the balance photodetector is in series by upper photodetector and lower photodetector, is used for
The modulated optical signal of dual output electro-optic intensity modulator is received respectively, and is converted into two photo-signals, final output
Electric signal subtract each other for two photo-signals after obtained differential current signal.
Further, the power adjustable of first light source and secondary light source, for realizing that the linearisation of signal is transmitted.
Further, the biased electrical of single output electro-optic intensity modulator and dual output electro-optic intensity modulator operating point
Pressure is different, and single offset angle for exporting electro-optic intensity modulator work is π, and the offset angle of dual output electro-optic intensity modulator work is
π/2。
The broadband analog signal linearisation fibre-optic transmission system (FOTS) of the present invention, in signal sending end, single electro-optic intensity that exports is adjusted
Device processed is modulated to optical signal all the way, and its modulated signal exported and another way optical signal are input to wavelength division multiplexer and carry out coupling
Close, the optical signal after dual output electro-optic intensity modulator couples wavelength division multiplexer is modulated again, and modulated signal is defeated
Go out to demodulation output on balance photodetector.
As a kind of preferred scheme of the broadband analog signal linearisation fibre-optic transmission system (FOTS) of the present invention, single output electricity
Light intensity modulator should be Mach and increase moral type electro-optic intensity modulator, and it builds material and is generally lithium niobate or other kinds of light
Electric material.
As a kind of preferred scheme of the broadband analog signal linearisation fibre-optic transmission system (FOTS) of the present invention, the dual output electricity
Light intensity modulator and negative single output electro-optic intensity modulator should be Mach and increase moral type electro-optic intensity modulator, and it builds material
Material is generally lithium niobate or other kinds of photoelectric material.
As a kind of preferred scheme of the broadband analog signal linearisation fibre-optic transmission system (FOTS) of the present invention, the balance photoelectricity
Detector, it is in series by upper photodetector and lower photodetector, for demodulating the modulated light letter received by receiving terminal
Number, its demodulated output signal is proportional to the difference of two photodetector output currents up and down.
In summary, the present invention provides a kind of broadband analog signal linearisation fibre-optic transmission system (FOTS), including analog radio frequency letter
Number source, it is single to export electro-optic intensity modulator and dual output electro-optic intensity modulator, for being modulated to optical signal, and simulation
Radiofrequency signal delayer, light source, wavelength division multiplexer, and balance photodetector.Compared with prior art, broadband of the invention
Analog signal linearly changes fibre-optic transmission system (FOTS), can effectively reduce in analog signal optical fiber telecommunications system by modulating/demodulating process
Caused nonlinear effect, improve signal transmission quality, the industrial utilization with height.
Brief description of the drawings
Fig. 1 is that the broadband analog signal of the present invention linearizes the structural representation of fibre-optic transmission system (FOTS)；
Fig. 2 is output result schematic diagram of the conventional optical communication systems based on two tone test；
The broadband analog signal that Fig. 3 is the present invention linearizes output result signal of the fibre-optic transmission system (FOTS) based on two tone test
Figure.
Component and label
1：Analog radio-frequency signal source, 2：Power divider, 3：Analog radio-frequency signal delayer, 4：First light source, 5：Second
Light source, 6：Single output electro-optic intensity modulator, 7：Wavelength division multiplexer, 8：Dual output electro-optic intensity modulator, 9：Photoelectricity is balanced to visit
Survey device.
Embodiment
Illustrate the embodiment of the present invention below by way of specific specific embodiment, those skilled in the art can be with
Content according to disclosed by this specification easily understands other advantages and effect of the present invention.The present invention can also pass through other
Different specific embodiments is carried out or applied, the various details in this specification can also be based on different viewpoints with
Using carrying out various modifications or change under without departing substantially from spirit of the invention.
Refer to Fig. 1~Fig. 3.It should be noted that the diagram provided in the present embodiment only illustrates this in a schematic way
The basic conception of invention, thus in illustrating only display with relevant component in the present invention rather than according to package count during actual implement
Mesh, shape and size are drawn, and form, quantity and the ratio of each component can be a kind of random change in its actual implementation, and its
Assembly layout form may also be increasingly complex.
Embodiment
As shown in figure 1, the present embodiment provides a kind of broadband analog signal linearisation fibre-optic transmission system (FOTS), including：
Analog radio-frequency signal source 1, it produces analog radio-frequency signal, is transferred to power divider 2.
Power divider 2, analog radio-frequency signal is divided into two-way by it, is respectively outputted to single output electro-optic intensity modulator 6
With analog radio-frequency signal delayer 3.
Analog radio-frequency signal delayer 3, it by the analog radio-frequency signal that power divider 2 is sent enter line delay and send to
Dual output electro-optic intensity modulator 8 is used as modulated signal.
First light source 4, it is to produce the high carrier wave optical signal of wavelength stability by laser, and it passes caused optical signal
It is defeated to be used as carrier signal to single output electro-optic intensity modulator 6.
Secondary light source 5, it is to produce the high carrier wave optical signal of wavelength stability by laser, and it passes caused optical signal
It is defeated to arrive wavelength division multiplexer 7.
Single output electro-optic intensity modulator 6, for being modulated to optical signal, and is output to wavelength-division multiplex by modulated signal
Device 7.Single output electro-optic intensity modulator 6 should be Mach and increase moral type electro-optic intensity modulator, and it builds material and is generally niobium
Sour lithium or other kinds of photoelectric material.
Wavelength division multiplexer 7, it is by the optical signal of two-way different wave length, wherein being by single output electro-optic intensity modulation all the way
Optical signal after the modulation of device 6, another way are the optical signals that secondary light source 5 is sent, and it is strong to be transferred to dual output electric light after power combing
Spend modulator 8.
Dual output electro-optic intensity modulator 8, it receives the analog radio-frequency signal conduct that analog radio-frequency signal delayer 3 is sent
The optical signal that modulated signal is sent to wavelength division multiplexer 7 carries out intensity modulation, and its both ends output optical signal is respectively outputted to
Balance photodetector 9.The dual output electro-optic intensity modulator 8 should be Mach and increase moral type electro-optic intensity modulator, and it builds
Material is generally lithium niobate or other kinds of photoelectric material.
Photodetector 9 is balanced, it is in series by upper photodetector and lower photodetector, is respectively used to receive
The both ends output optical signal of dual output electro-optic intensity modulator 8, and it is converted into two photo-signals, the electricity of final output
Signal is the differential current signal obtained after two photo-signals are subtracted each other.
The broadband analog signal linearisation fibre-optic transmission system (FOTS) of the present invention, in signal sending end, single electro-optic intensity that exports is adjusted
The optical signal that first light source 4 exports is modulated by device 6 processed, and is coupled with the optical signal that secondary light source 5 exports, and is output to wavelength-division
Multiplexer 7, the optical signal after dual output electro-optic intensity modulator 8 couples wavelength division multiplexer 7 are modulated, and by output signal
It is sent to balance photodetector 9 and is demodulated output.
As an example, first light source 4 and secondary light source 5 use two laser light sources, as carrier signal.
As an example, described single output electro-optic intensity modulator 6 should be Mach and increase moral type electro-optic intensity modulator, its structure
Construction material is generally lithium niobate or other kinds of photoelectric material.In the present embodiment, increase Dare (Mach- using lithium niobate Mach
Zehnder) single output electro-optic intensity modulator.
As an example, described dual output electro-optic intensity modulator 8, which should be Mach, increases moral type electro-optic intensity modulator, its structure
Construction material is generally lithium niobate or other kinds of photoelectric material.In the present embodiment, increase Dare (Mach- using lithium niobate Mach
Zehnder) dual output electro-optic intensity modulator.
As an example, the balance photodetector 9, in series by upper photodetector and lower photodetector, use
In the modulated optical signal received by demodulation receiving terminal.The demodulation of formula is balanced by using balance photodetector, can be with
Obtain high linearity, the transmitting telecommunication number of low noise.In the present embodiment, the demodulation side of the photodetector selection balanced type used
Formula.
In the present embodiment, the modulated optical signal obtained by after intensity modulation process and modulation is analyzed, it is described strong
It is that lithium niobate Mach increases Dare electro-optic intensity modulator (Mach-Zehnder) to spend modulator.Certainly, using other photoelectric materials
The Mach increasing Dare intensity modulator implementation process of composition is similar, and can be analyzed according to following analysis method.It is single
Export the modulated optical signal P of the output end of electro-optic intensity modulator 63It is described as follows：
Wherein, P2Represent the power of single output input carrier optical signal of electro-optic intensity modulator 6, m=π VRF(t)/Vπ, Vπ
Represent half-wave voltage amplitude, VRF(t) modulated signal of input is represented.
In this example, the both ends Output optical power of dual output electro-optic intensity modulator 8 is respectively P4、P5, its expression formula is such as
Under：
In formula, P1Represent the luminous power that secondary light source 5 exports.
In this example, photodetector output end I is balancedoutFor the power output P of dual output electro-optic intensity modulator 84、P5It is right
The difference of photoelectric current is answered, its expression formula is as follows：
α is the photoelectric conversion factors of balance photodetector in formula.
Taylor expansion is carried out to (4) formula, can obtain output end is：
Wherein, η=P2/P1To can adjust constant.
From (5) formula, η, which takes, 2/3 can eliminate third-harmonic component in output, so as to realizing to a certain extent
Linearlyization is transmitted.
In this example, the mutual intermodulation characteristic of three ranks of legacy system and the system is compared using the method for two tone test
Right, its Numerical Simulation Results as shown in Figure 2 and Figure 3, as can be seen from Figure, substantially will in the system by the peak value of the mutual intermodulation component of three ranks
Less than legacy system, therefore demonstrate the non-linear relatively low characteristic of the system.
The invention provides a kind of broadband analog signal to linearize fibre-optic transmission system (FOTS), implements the side of the technical scheme
Method and approach are a lot, such as different transmission signals, or intensity modulator of different transmission environments selection different materials etc..
Described above is only the preferred embodiment of the present invention, it is noted that for the common researcher of the art,
Without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications also should be regarded as this hair
Bright protection domain.The available prior art of each part being not known in the present embodiment is realized.
Claims (7)
1. a kind of broadband analog signal linearizes fibre-optic transmission system (FOTS), it is characterised in that including：
Analog radio-frequency signal source (1), power divider (2), analog radio-frequency signal delayer (3), the first light source (4), the second light
Source (5), single output electro-optic intensity modulator (6), wavelength division multiplexer (7), dual output electro-optic intensity modulator (8), balance photoelectricity
Detector (9)；The analog radio-frequency signal source (1) produces analog radio-frequency signal, is transferred to power divider (2)；The power
Analog radio-frequency signal is respectively outputted to single output electro-optic intensity modulator (6) and analog radio-frequency signal delayer by distributor (2)
(3)；The signal that power divider (2) is sent is entered line delay and sends dual output by the analog radio-frequency signal delayer (3)
Electro-optic intensity modulator (8) is used as modulated signal；First light source (4) is strong to single output electric light by caused optical signal transmission
Degree modulator (6) is used as carrier signal；The secondary light source (5) is by caused optical signal transmission to wavelength division multiplexer (7)；It is described
Single output electro-optic intensity modulator (6) is used to be modulated optical signal, and modulated signal is output into wavelength division multiplexer (7)；
The wavelength division multiplexer (7) will be by the optical signal after singly output electro-optic intensity modulator (6) modulation and secondary light source (5) hair
The optical signal sent, dual output electro-optic intensity modulator (8) is transferred to after power combing；The dual output electro-optic intensity modulator
(8) analog radio-frequency signal that analog radio-frequency signal delayer (3) is sent, is received to send out wavelength division multiplexer (7) as modulated signal
The optical signal sent carries out intensity modulation, and its both ends output optical signal is respectively outputted to balance photodetector (9).
2. broadband analog signal linearisation fibre-optic transmission system (FOTS) according to claim 1, it is characterised in that the balance photoelectricity
Detector (9) is in series by upper photodetector and lower photodetector, is respectively used to receive the modulation of dual output electro-optic intensity
The both ends output optical signal of device (8), and two photo-signals are converted into, the electric signal of final output is two photoelectric currents
The differential current signal obtained after signal subtraction.
3. broadband analog signal linearisation fibre-optic transmission system (FOTS) according to claim 1, it is characterised in that first light source
(4) and secondary light source (5) power adjustable, for realize signal linearisation transmit.
4. broadband analog signal linearisation fibre-optic transmission system (FOTS) according to claim 1, it is characterised in that single output electricity
Light intensity modulator (6) is different with the bias voltage of dual output electro-optic intensity modulator (8) operating point, and single electro-optic intensity that exports is adjusted
The offset angle of device (6) work processed is π, and the offset angle of dual output electro-optic intensity modulator (8) work is pi/2.
5. broadband analog signal linearisation fibre-optic transmission system (FOTS) according to claim 1, it is characterised in that by described in regulation
The time delay of analog radio-frequency signal delayer (3), realize electric signal and wavelength division multiplexer that analog radio-frequency signal delayer (3) is sent
(7) optical signal sent reaches the dual output electro-optic intensity modulator (8) simultaneously.
6. broadband analog signal linearisation fibre-optic transmission system (FOTS) according to claim 1, it is characterised in that single output electricity
Light intensity modulator (6) is that Mach increases moral type electro-optic intensity modulator.
7. broadband analog signal linearisation fibre-optic transmission system (FOTS) according to claim 1, it is characterised in that the dual output electricity
Light intensity modulator (8) is that Mach increases moral type electro-optic intensity modulator.
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| CN108152582A (en) * | 2017-12-25 | 2018-06-12 | 昆明理工光智检测科技有限公司 | A kind of integrated light guide microwave signal frequency measuring system and measuring method |
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| US7079780B1 (en) * | 1999-05-28 | 2006-07-18 | Northrop Grumman Corporation | Linearized optical link using a single Mach-Zehnder modulator and two optical carriers |
| US8059969B1 (en) * | 2008-06-18 | 2011-11-15 | Hrl Laboratories, Llc | Enhanced linearity RF photonic link |
| CN102624460A (en) * | 2012-01-16 | 2012-08-01 | 北京大学 | Modulator for optical fibre linear transmission and third-order intermodulation suppression method for modulator |
| CN103401616A (en) * | 2013-08-06 | 2013-11-20 | 电子科技大学 | High-linearity radio frequency light transmission system and method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9172471B2 (en) * | 2013-03-15 | 2015-10-27 | The United States Of America, As Represented By The Secretary Of The Navy | System and method for suppression of even-order photodiode distortions |
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2016
- 2016-05-13 CN CN201610319712.9A patent/CN105790840B/en not_active Expired - Fee Related
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|---|---|---|---|---|
| US7079780B1 (en) * | 1999-05-28 | 2006-07-18 | Northrop Grumman Corporation | Linearized optical link using a single Mach-Zehnder modulator and two optical carriers |
| US8059969B1 (en) * | 2008-06-18 | 2011-11-15 | Hrl Laboratories, Llc | Enhanced linearity RF photonic link |
| CN102624460A (en) * | 2012-01-16 | 2012-08-01 | 北京大学 | Modulator for optical fibre linear transmission and third-order intermodulation suppression method for modulator |
| CN103401616A (en) * | 2013-08-06 | 2013-11-20 | 电子科技大学 | High-linearity radio frequency light transmission system and method |
Non-Patent Citations (1)
| Title |
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| A Broadband Linearized Coherent Analog Fiber-Optic Link Employing Dual Parallel Mach-Zehnder Modulators;Guanghao Zhu 等;《IEEE PHOTONICS TECHNOLOGY LETTERS》;20091101;第1627-1629页 * |
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