CN101277154B - For generation of the optical launcher of the optical modulation for being transferred to remote receiver via optical fiber link - Google Patents
For generation of the optical launcher of the optical modulation for being transferred to remote receiver via optical fiber link Download PDFInfo
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- CN101277154B CN101277154B CN200810000074.XA CN200810000074A CN101277154B CN 101277154 B CN101277154 B CN 101277154B CN 200810000074 A CN200810000074 A CN 200810000074A CN 101277154 B CN101277154 B CN 101277154B
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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
- H04B10/505—Laser transmitters using external 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
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
-
- 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
- H04B10/508—Pulse generation, e.g. generation of solitons
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- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optics & Photonics (AREA)
- Optical Communication System (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
- Semiconductor Lasers (AREA)
Abstract
The invention provides a kind of for generation of optical modulation for the optical launcher being transferred to remote receiver via optical fiber link, it comprises: laser; Modulator, it carries out external modulation to produce the optical signalling comprised containing modulation intelligence component with RF signal to described optical output signal; And phase-modulator, its output being coupled to described modulator or be directly coupled to described laser output for reduction or eliminate the noise signal produced in described laser.
Description
Technical field
The present invention relates to a kind of optical transmission system for analog or digital signal, and in particular, relate to a kind of system using external modulation solid-state laser.In addition, the present invention relates to and eliminate in described system by the many noise component(s) (white noise) that produces or noises (itself and frequency change on the contrary, and are therefore commonly referred to " 1/f " noise) produced by the fluctuation in the bias current of laser or thermal environment of may originating such as the Brownian movement of such as charge carrier in semiconductor laser.
Background technology
The analog intensity of electricity consumption Signal shock light-emitting diode (LED) or semiconductor laser is considered to the most straightforward procedure for transmitting the analog signals such as such as voice and video signal on optical fiber known in technique.Although the advantage of this type of analogue transmission technology is to have significantly less bandwidth requirement compared with such as digit pulse code modulated or the Digital Transmission such as simulation or pulse frequency modulated, Modulation and Amplitude Modulation is used usually to propose comparatively strict requirement to the noise of reflector and distortion characteristic.
Due to these reasons, when being applied to employing and there is the short transmission link of the scattered optical fiber link penetrated, use directly modulation technology in conjunction with 1310nm laser.For being applied to metropolitan area and long-distance optical fiber transmission link, link low-loss requires the 1550nm laser using external modulation, generally extends over very long distance (100km) and high-frequency (more than 900MHz).The limiting factor of this type of link may be the conversion of the residual phase noise from laser, and described residual phase noise converts amplitude noise to via the scattering existed in optical fiber link.The present invention be therefore absorbed in that the noise that is provided for being associated with the phase noise of laser eliminates simple and the problem of low-cost system, make simulated optical export and can be used for metropolitan area and long-reach optics network, in particular for the analogue transmission of broadband RF signal.
The direct current modulation of laser also becomes known for digit optical transmission system, such as dense wave division multipurpose (DWDM) system.Referring to " DWDM Networks, Devices, and Technology " (IEEEPress, the 2003,154th page) of (such as) Kartalopoulos.
Except to except the low noise figure required by 1550nm simulated optical transmission system, described system is also necessary for highly linear.Distortion intrinsic in specific simulating emitter stops linear electrical modulation signal to be optical signalling by linear transformation, but causes described distorted signals.These impacts are harmful especially for multi-channel video transmission, fabulous linear in case channel is interfering with each other of described multi-channel video transmission requirement.The simulated optical system of highly linearized is widely used in commercial analogue system, such as, broadcast TV transmission, CATV, interactive TV and visual telephone transmission.
As the alternative to direct current modulation, the known external modulator using continuous wave (CW) laser in the prior art in optical transmission system.5th, 699, No. 179 United States Patent (USP)s describe a kind of feedforward linearized simulated optical reflector of external modulation, its compound secondary (CSO) distortion component brought out for reducing optical fiber.
To the linearizing research of optics and other non-linear reflector for some time, but proposed solution has shortcoming in practice.The bandwidth that major applications discussed above has is for excessive many actual embodiments.Complicated system component is needed, such as optical power combiner and multiple light source for linearizing feed-forward technique.Quasi-optics feed-forward technique suffers similar complexity problem, and needs the part mating fabulous in addition.But as discussed below, the forward direction technology eliminated for phase noise is the practical technique that the good technology of many exploitations can be used to implement.
Before making the present invention, not yet application is coupled to the phase-modulator of externally modulated laser for the object eliminating the phase noise component produced by the various noise sources in the semiconductor structure of laser.It should be noted that semiconductor laser represents noise in its amplitude (being commonly referred to relative intensity noise) and its phase place.These noise characteristics have nothing to do with optical maser wavelength substantially, but noise can sentence different modes appearance at different wave length in single mode fibers transmission.The main inside of phase place and amplitude noise mechanism is caused to be spontaneous emission in the active region of laser.Because the photon of spontaneous emission does not have given phase relation with those photons produced via stimulated emission, thus the amplitude of gained light field and phase place are all affected.Spontaneous emission process is well-known, and has been shown as and is described by Brownian motion process, and wherein noise spectrum is constant (white noise) substantially in frequency of operation.At laser external, the environmental impacts such as such as microphone effect, temperature fluctuation and bias current noise also can produce phase noise in light field.These events cause light phase noise usually, and it represents the noise spectrum with " 1/f " correlation.
The present invention manages to eliminate by feedforward the proper phase noise that minimizes from semiconductor laser and no matter the driving mechanism of noise is how.
Summary of the invention
1. goal of the invention
The object of the present invention is to provide a kind of improvement optical transmission system using externally modulated laser.
Another object of the present invention is to compensate for the noise in the laser of optical transmission system.
Another object of the present invention is to provide a kind of external phase modulator reduced to improve phase noise for external modulation 1550nm simulated optical transmission system.
Another object of the present invention is that providing a kind of is applicable to remote dispersive optical fiber media and uses externally modulated laser together with the highly linear optical transmission system of the phase-correcting circuit and phase-modulator that are coupled to optical signalling.
Another object of the present invention is to provide a kind of phase-shift circuit for reducing the residual phase noise from externally modulated laser in the simulated optical transmission system being applicable to remote dispersive optical fiber media.
The present invention also aims to provide the phase noise compensation process in a kind of broadband analogue optical transmission system.
2. inventive features
Briefly and put it briefly, the invention provides a kind of for generation of optical modulation for the optical launcher being transferred to remote receiver via optical fiber link, it comprises: laser; Modulator, it is for carrying out external modulation to produce the optical signalling comprised containing modulation intelligence component with RF signal to described laser; And phase-modulator, its output being coupled to described modulator is for eliminating the noise signal produced in described laser.
On the other hand, the invention provides a kind of for generation of optical modulation for via the optical launcher of dispersing optics link transmission to remote receiver, it has: semiconductor laser, and it is for generation of the optical signalling with the phase noise that is associated; Noise canceller circuit, it is coupled to the output of described laser and the optical phase modulator comprised for reducing the phase noise produced in laser; And external modulator, it is coupled to the output of described phase-modulator and inputs for receiving broadband analogue radiofrequency signal and modulate described optical signalling.
On the other hand, the invention provides a kind of for the optical transmission system via dispersive optical fiber link, it comprises: the optical launcher with the input of analog or digital RF signal; Semiconductor laser; Modulation circuit, it is for laser described in external modulation; And for eliminating the circuit of the optical phase modulation product that the noise that produces with semiconductor laser is associated.
In another aspect of this invention, a kind of noise canceller circuit for reducing phase noise in analog signal transmission is provided, the output optical signalling of the external modulator from semiconductor laser is split into two paths by it, one lead to phase-modulator and another lead to frequency discriminator.Amplitude and phase place adjust described phase-modulation erasure signal to mate frequency or the phase place dependence of the phase noise of laser generation.The phase place of described signal by the delay in the one in described path or phase adjustment element synchronous.Then and secondary signal main by phase-modulator restructuring only has amplitude-modulated single optical signalling to produce.Therefore, phase-modulator modulates the main signal from semiconductor laser in the mode minimizing gained phase noise, thus analog signal is suitable for via dispersive optical fiber link transmission.
According to this disclosure (comprise following be described in detail in) and by putting into practice the present invention, be understood by those skilled in the art that extra object of the present invention, advantage and novel feature.When hereafter describing of the present invention referring to preferred embodiment, the present invention should be understood and be not limited to this.What can obtain herein teaching those skilled in the art will realize that additional application in other field, amendment and embodiment, described additional application, amendment and embodiment belong in the scope of the invention that discloses in this article and advocate, and the present invention can have remarkable effectiveness relative to it.
Accompanying drawing explanation
In conjunction with the drawings referring to following detailed description, will understand better and comprehend these and other feature of the present invention and advantage, wherein:
Fig. 1 is the height simplified block diagram of external modulation optical transmission system well known in the prior art;
Fig. 2 is the height simplified block diagram of the first embodiment according to optical transmission system of the present invention;
Fig. 3 is the height simplified block diagram of the second embodiment according to optical transmission system of the present invention.
State novel feature of the present invention and characteristic in the dependent claims.But, by by reference to the accompanying drawings referring to the detailed description of specific embodiment being come to best understanding the present invention itself and further feature and advantage.
Embodiment
Now will describe details of the present invention, comprise its exemplary aspect and embodiment.Referring to the accompanying drawings and the description below, same reference numerals for identifying identical or intimate element, and wishes the principal character that one exemplary embodiment is described with the graphic mode highly simplified.In addition, do not wish that accompanying drawing describes each feature of practical embodiments or the relative size of institute's elements depicted, and accompanying drawing is not drawn in proportion.
Fig. 1 is the block diagram utilizing the prior art optical launcher of external modulator as the the 5th, 699, No. 179 United States Patent (USP) represents.Described reflector (usually with 10 displayings) via fiber path 30 to remote receiver 60 transmitting optics signal.Reflector 10 comprises semiconductor laser 12, and it produces continuous wave (CW) and exports.The representative instance of this type of laser is distributed Feedback (DFB) laser and/or Fabry-Perot laser, and it produces output beam with the wavelength of 1550nm usually.Unmodulated optical signalling from laser is coupled to modulator 16 by optical fiber 14.Modulator 16 can be that in the single modulator of such as Mach-Zehnder modulator, cascade MZ modulator or such as feedforward linearized circuit one is with modulator.Modulator 16 also receives broadband RF signal via terminal 18 and circuit 20, such as Modulation and Amplitude Modulation residual sideband (AM-SDB) cable TV (CATV) or vision signal.In addition, when using feedforward linearized circuit, provide to modulator 16 signal that depolarizes via terminal 22 and circuit 24.The described signal that depolarizes for depolarizing to the optics input arriving error correction modulator (not shown) in modulator 16.
What carry video data is coupled to amplifier 28 through optical modulation by optical fiber link 26.Amplifier 28 is erbium doped optic fibre amplifier (EDFA) normally.Optical signalling through amplifying is coupled to the optical fiber transmission line 30 towards receiver 60.Described optical fiber transmission line 30 can be the long-distance link extending past a few km.In the case, such as line amplifier such as EDFA 28 grade can be provided, described signal is boosted to required level with spacing distance wherein along described circuit.At receiver 60 place, the amplifier optical signalling that (not shown) imports into boost also can be provided.Then the signal through boosting is applied to photoelectric detector and carries out rectification to produce the signal of telecommunication at receiver 60 place to it, the described signal of telecommunication represents original video or the data-signal at circuit 50 place.
Fig. 3 is the block diagram of the optical launcher utilizing external modulator according to a first embodiment of the present invention.Optical signalling is transferred to remote receiver via fiber path 30 by described reflector (usually showing with 200).Reflector 200 comprises semiconductor laser 101, and it produces continuous wave (CW) and exports.The representative instance of this type of laser is distributed Feedback (DFB) laser and/or Fabry-Perot laser, and it produces output beam with the wavelength of 1550nm usually.
The edge emitting semiconductor laser used in Fig. 3 system is preferably distributed feedback laser (DFB), but can use Fabry-Perot (FP) laser equally.Distributed Feedback Laser is optimization approach, be mainly included in single zlasing mode, and the optical energy of FP laser is dispersed in the middle of many patterns because its optics exports.In a preferred embodiment, described laser is the outside cavity gas laser of laser optical output wavelength within the scope of 1530 to 1570nm.
Unmodulated optical signalling from laser splits into two parts; Part I is coupled to modulator 102 by optical fiber 103.Modulator 102 can be that in the single modulator of such as Mach-Zehnder modulator, cascade MZ modulator or such as feedforward linearized device one is with modulator.Modulator 102 receives broadband RF signal or the digital signal of such as Modulation and Amplitude Modulation residual sideband (AM-SDB) cable TV (CATV) or vision signal via terminal 104 and circuit 105.Analog signal can have the bandwidth that is greater than an octave and carry multiple channel.In addition, when using feedforward linearized device, the configuration being similar to Fig. 1 provides to modulator the signal that depolarizes like that.The described signal that depolarizes for depolarizing to the optics input arriving error correction modulator (not shown) in modulator 102.
As mentioned above, the optical signalling of laser exports and splits into two parts: a part is applied to modulator 102; Another part is coupled to frequency discriminator 107 by optical fiber 106.
The output of frequency discriminator 107 is applied to attenuator 108 to adjust the amplitude of described signal rightly, matches with the amplitude of the phase-modulated component introduced with the phase noise characteristic of laser 101.
The output of attenuator 108 is then connected to phase offset circuit 109.Circuit 109 corrects the time lag compared with the described signal being applied directly to modulator 102 of the signal output being applied to circuit element 107,108.In paid close attention to transmission of video frequency band (be 50MHz-1000MHz for traditional C ATV system), the phase noise of semiconductor laser 101 is " in vain ", and namely the spectral power density of noise and frequency have nothing to do.In the case, needs are had constant (adjustable) gain by phasing path 106,107,108,109, its postpone just in time with the delay matching of predominating path 103,102 and 110.The aspect that needs illustrate is the effect of frequency discriminator 107 pairs of signals, and the optics specifically in phasing path is to the result of electricity transfer process.When photodiode detects optical signalling, observe the phenomenon being called shot noise.This noise is produced with the statistic processes producing electron-hole pair by absorb photons in the photodiode.This noise is inevitable for all practical purposes.Therefore, shot noise will form lower limit to attainable phase noise amount of cancellation.
Then the output of phase offset circuit 109 is applied to phase-modulator 110, with so that by its phase-modulation phasing is incorporated in optical signalling with so that correct or noise that compensate for laser produces.
Be given as from the Spectral Noise Density of the photoelectric current of photodiode generation
<i
n 2>＝2eI
p
Wherein e is electron charge and I
pit is DC photoelectric current.Those skilled in the art will recognize such fact immediately: noise power has linear dependence to received optical power, and is therefore improved along with the increase of institute's received power by the signal to noise ratio of the process of shot noise domination.Basic Design in the proposed invention of this representative is traded off.Be switched to phasing path 106,107,108,109 ... in more power by with the Optical output power of reflector for cost improve final phase noise eliminate.
The output of phase-modulator 110 is coupled to amplifier 112 via optical fiber 111, and described amplifier 112 is then connected to optical fiber or link 30.At far-end, optical fiber or link 30 are connected to receiver, and received optical signalling is converted to RF signal by described receiver, are similar to represent in Fig. 1.
Fig. 2 is the block diagram of the optical launcher utilizing external modulator according to a second embodiment of the present invention.Optical signalling is transferred to remote receiver via fiber path 30 by described reflector (usually showing with 100).Reflector 100 comprises semiconductor laser 101, and it produces continuous wave (CW) and exports.The representative instance of this type of laser is distributed Feedback (DFB) laser and/or Fabry-Perot laser, and it produces output beam with the wavelength of 1550nm usually.Unmodulated optical signalling from laser splits into two parts; A part is coupled to phase-modulator 110 by optical fiber 103.Phasing is incorporated in optical signalling by phase-modulator 110, with so that correct or the noise that produces of compensate for laser.The CW of phase-modulator 110 exports and is coupled to modulator 102, to produce the optical signalling containing modulation intelligence.
Modulator 102 can be that in single modulator, cascade MZ modulator or the such as feedforward linearized devices such as such as Mach-Zehnder modulator one is with modulator.Modulator 102 receives such as broadband RF signal or the digital signal such as Modulation and Amplitude Modulation residual sideband (AM-SDB) cable TV (CATV) or vision signal via terminal 104 and circuit 105.In addition, when using feedforward linearized device, the configuration being similar to Fig. 1 is such, provides to modulator the signal that depolarizes.The described signal that depolarizes for depolarizing to the optics input arriving error correction modulator (not shown) in modulator 102.
As described above, the optical signalling of laser exports and is split into two parts: a part is applied to phase-modulator 110; Another part is coupled to frequency identification circuit 107 by optical fiber 106.
The output of frequency discriminator 107 is applied to attenuator 108 to adjust the amplitude of described signal rightly, matches with the amplitude of the phase-modulated component introduced with the phase noise characteristic of laser 101.
The output of attenuator 108 is then connected to phase offset circuit 109.Circuit 109 corrects the time lag compared with the described signal being applied to phase-modulator 110 of the signal output being applied to circuit element 107,108.In paid close attention to transmission of video frequency band (be 50MHz-1000MHz for traditional C ATV system), the phase noise of semiconductor laser 101 is " in vain ", and namely the spectral power density of noise and frequency have nothing to do.In the case, needs are had constant (adjustable) gain by phasing path 106,107,108,109, its postpone just in time with the delay matching of predominating path 103,102 and 110.Need the aspect illustrated to be frequency discriminator 107, the optics specifically in phasing path is to electricity transfer process.When photodiode detects optical signalling, observe the phenomenon being called shot noise.This noise is produced with the statistic processes producing electron-hole pair by absorb photons in the photodiode.This noise is actually inevitable.Therefore, shot noise will apply lower limit to attainable phase noise amount of cancellation.
Without departing from the spirit and scope of the present invention, it will be apparent to those skilled in the art that many changes and amendment.For example, although be described and illustrate in the context of video or multichannel TV signal madulation laser or light-emitting diode, the inherent distortion of such as other non-linear device such as amplifier can be eliminated by this technology to a great extent.The precision adjustment of the relative phase of the signal mainly and in secondary path is in secondary path in the illustrated embodiment, but this also can in the predominating path with rough adjustment.Secondary path is preferred, because this type of delay in predominating path may have inappropriate impedance to this path.
The various aspects of technology of the present invention and device can be implemented in digital circuit or computer hardware, firmware, software or its combination.Circuit of the present invention can be implemented or above implement at the software (it automatically or as required can download to computer product) being positioned at network node or website place in computer product (it is visibly implemented in machine-readable storage device and performs for programmable processor).Aforementioned techniques can be performed by the gate array of (such as) single central processing unit, multiprocessor, one or more digital signal processors, gate or hard-wired logic, for performing a sequence signal or instruction repertorie to perform function of the present invention by operating input data and produce output.Described method can advantageously be implemented in one or more computer programs that can perform on programmable system, and described programmable system comprises at least one through coupling to receive data and instruction from data-storage system and to the programmable processor of data-storage system transmitting data and instruction, at least one input/output device and at least one output device.Each computer program can optionally be implemented with advanced procedures or OO programming language or with compilation or machine language; And under any circumstance, described language can be compiling or interpreter language.For example, suitable processor comprises general purpose microprocessor and special microprocessor.One, processor will receive instruction and data from read-only memory and/or random access memory.The storage device being suitable for visibly implementing computer program instructions and data comprises the nonvolatile memory of form of ownership, for example comprises: semiconductor device, such as EPROM, EEPROM and flash memory device; Disk, such as internal hard drive and removable dish; Magneto optical disk; And CD-ROM dish.Any aforementioned means can be supplemented by specially designed application-specific integrated circuit (ASIC) (ASIC) or be incorporated in ASIC.
To understand, each in said elements or both or both above structures that together also effectively can be applied to other type different from the above-mentioned type.
Although the present invention illustrated and be described as implementing in optical transmission system, do not wish that it is limited to shown details, because various amendment and structural change can be made when departing from spirit of the present invention never in any form.
When not doing to analyze further, foregoing teachings so will represent main points of the present invention comprehensively, other people are easily adjusted for various application it when not being omitted in the feature of intrinsic propesties prior art position forming completely the present invention one or particular aspects by application current knowledge, and therefore this type of adjust should and in the hope equivalence meaning that is included in appended claims and scope.
Claims (17)
1., for generation of an optical launcher for the optical modulation for being transferred to remote receiver via optical fiber link, it comprises:
Laser, it is for generation of the base band optical signalling of the noise expansion comprised on frequency spectrum;
Modulator, it is for modulating to produce the optical signalling containing modulation intelligence to described base band optical signalling with RF signal;
Phase-modulator, its output being coupled to described modulator adjusts the described optical signalling containing modulation intelligence for the described optical signalling containing modulation intelligence of reception and the phase noise for being associated with described base band optical signalling by elimination, and produces the output optical signalling closed with described optical fiber link lotus root; And
Phase-correcting circuit, it is coupled between described laser and described phase-modulator, described phase-correcting circuit comprises the frequency discriminator with input and output, the described input coupling of described frequency discriminator is with the part receiving described base band optical signalling, and the described output of described frequency discriminator is coupled to photodiode to be eliminated to provide the feedforward of described phase noise in order to control described phase-modulator the phase noise be associated with described base band optical signalling to be converted to modulation signal.
2. optical launcher according to claim 1, wherein said laser is semiconductor laser, and the phase noise be associated with described base band optical signalling eliminated by described phase-modulator.
3. optical launcher according to claim 1, wherein said RF signal is Modulation and Amplitude Modulation residual sideband cable TV or vision signal.
4. optical launcher according to claim 1, wherein said modulator is Mach-Zehnder modulator.
5. optical launcher according to claim 1, the wave-length coverage of the described base band optical signalling wherein exported from described laser is from 1530 to 1570nm.
6. optical launcher according to claim 1, wherein said RF signal is broadband analog signal input, and it has the bandwidth that is greater than an octave and comprises multiple dissimilarity information bearer channel.
7. optical launcher according to claim 1, wherein said phase-modulator optionally can carry out adjusting compensating the distortion that the dispersion in described optical fiber link produces according to the length of described optical fiber link.
8. optical launcher according to claim 1, to be wherein switched in described phase-correcting circuit more power by with the Optical output power of described reflector for cost is eliminated to improve final phase noise.
9., for generation of an optical launcher for the optical modulation for being transferred to remote receiver via optical fiber link, described optical launcher comprises:
Laser, it is for generation of the base band optical signalling of the noise expansion comprised on frequency spectrum;
Phase-modulator, its output being coupled to described laser is for the output optical signalling produced through phase-modulation;
Phase-correcting circuit, it is coupled to the described output of described laser, to provide electrical input signal to described phase-modulator, adjust described base band optical signalling for by described phase-modulator by eliminating the phase noise be associated with described base band optical signalling; And
Modulator, it is for modulating, to produce the optical signalling containing modulation intelligence the described output optical signalling through phase-modulation that described phase-modulator produces with RF signal.
10. optical launcher according to claim 9, wherein said laser comprises semiconductor laser, and described phase-modulator provides phase noise to eliminate in described base band optical signalling.
11. optical launchers according to claim 9, wherein said RF signal is digital signal.
12. optical launchers according to claim 9, wherein said modulator is Mach-Zehnder modulator.
13. optical launchers according to claim 9, wherein said phase-correcting circuit is coupled with described phase-modulator, and comprise the frequency discriminator of the input with the described output being connected to described laser and be coupled to the photodiode of described frequency discriminator, the described phase noise in described base band optical signalling is converted to the modulation signal controlling described phase-modulator.
14. optical launchers according to claim 9, the wave-length coverage of the described base band optical signalling wherein exported from described laser is from 1530 to 1570nm.
15. optical launchers according to claim 9, wherein said RF signal is broadband analog signal input, and it has the bandwidth that is greater than an octave and comprises multiple dissimilarity information bearer channel.
16. optical launchers according to claim 9, wherein said phase-modulator can carry out adjusting compensating according to the length selectivity of described optical fiber link the distortion that the dispersion in described optical fiber link produces.
17. optical launchers according to claim 9, wherein said phase-correcting circuit is for adjusting amplitude and the phase place of described base band optical signalling.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11/729,255 US7792432B2 (en) | 2006-03-02 | 2007-03-28 | Externally modulated laser optical transmission system with feed forward noise cancellation |
| US11/729,255 | 2007-03-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101277154A CN101277154A (en) | 2008-10-01 |
| CN101277154B true CN101277154B (en) | 2015-09-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN200810000074.XA Expired - Fee Related CN101277154B (en) | 2007-03-28 | 2008-01-04 | For generation of the optical launcher of the optical modulation for being transferred to remote receiver via optical fiber link |
Country Status (4)
| Country | Link |
|---|---|
| JP (2) | JP5425409B2 (en) |
| KR (1) | KR20080088352A (en) |
| CN (1) | CN101277154B (en) |
| TW (1) | TW200840362A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8750441B2 (en) * | 2010-12-20 | 2014-06-10 | Texas Instruments Incorporated | Signal cancellation to reduce phase noise, period jitter, and other contamination in local oscillator, frequency timing, or other timing generators or signal sources |
| JP6232334B2 (en) * | 2014-04-17 | 2017-11-15 | 日本電信電話株式会社 | Laser phase noise reduction device |
| CN109286124B (en) * | 2018-09-18 | 2020-07-10 | 上海交通大学 | Laser linewidth compression method and system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8602017D0 (en) * | 1986-01-28 | 1986-03-05 | British Telecomm | Reducing fluctuations in radiation beam characteristic |
| US5200964A (en) * | 1991-03-12 | 1993-04-06 | General Instrument Corporation | Broad linewidth lasers for optical fiber communication systems |
| JP3223562B2 (en) * | 1992-04-07 | 2001-10-29 | 株式会社日立製作所 | Optical transmission device, optical transmission device, and optical modulator |
| JP3121504B2 (en) * | 1994-10-31 | 2001-01-09 | 日本電信電話株式会社 | Optical transmission circuit |
| US7848661B2 (en) * | 2005-03-15 | 2010-12-07 | Emcore Corporation | Directly modulated laser optical transmission system with phase modulation |
-
2007
- 2007-12-10 TW TW096147088A patent/TW200840362A/en unknown
-
2008
- 2008-01-04 CN CN200810000074.XA patent/CN101277154B/en not_active Expired - Fee Related
- 2008-01-10 KR KR1020080002952A patent/KR20080088352A/en not_active Application Discontinuation
- 2008-03-28 JP JP2008114509A patent/JP5425409B2/en not_active Expired - Fee Related
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2013
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| Publication number | Publication date |
|---|---|
| TW200840362A (en) | 2008-10-01 |
| JP5425409B2 (en) | 2014-02-26 |
| JP2008252910A (en) | 2008-10-16 |
| JP2013255264A (en) | 2013-12-19 |
| CN101277154A (en) | 2008-10-01 |
| KR20080088352A (en) | 2008-10-02 |
| JP5847771B2 (en) | 2016-01-27 |
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