CN101277154A - Externally modulated laser optical transmission system with feed forward noise cancellation - Google Patents
Externally modulated laser optical transmission system with feed forward noise cancellation Download PDFInfo
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- CN101277154A CN101277154A CNA200810000074XA CN200810000074A CN101277154A CN 101277154 A CN101277154 A CN 101277154A CN A200810000074X A CNA200810000074X A CN A200810000074XA CN 200810000074 A CN200810000074 A CN 200810000074A CN 101277154 A CN101277154 A CN 101277154A
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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
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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
- H04B10/508—Pulse generation, e.g. generation of solitons
Abstract
An optical transmitter for generating a modulated optical signal for transmission over a fiber optic link to a remote receiver including a laser; a modulator for directly amplitude modulating the laser with an analog RF signal to produce an optical signal including an amplitude modulated information-containing component; and a phase modulator coupled to the output of the laser for canceling the noise signals generated in the laser.
Description
Technical field
The present invention relates to a kind of optical transmission system that is used for the analog or digital signal, and in particular, relate to a kind of system that uses the external modulation solid-state laser.In addition, the present invention relates to eliminate in the described system by the many noises that may originate the noise component(s) (white noise) that produces or produce such as the Brownian movement of charge carrier (its and frequency change on the contrary, and so are commonly referred to " 1/f " noise) for example in the semiconductor laser by the bias current or the fluctuation in the thermal environment of laser.
Background technology
Be considered in this technology known being used for the analog intensity of direct modulated luminescence diode of the signal of telecommunication (LED) or semiconductor laser and on optical fiber, transmit for example straightforward procedure of analog signal such as voice and video signal.Have significantly less bandwidth requirement although the advantage of this type of analogue transmission technology is to compare with Digital Transmission such as for example digit pulse code modulated or simulation or pulse frequency modulated, use Modulation and Amplitude Modulation usually the noise and the distortion characteristic of reflector to be proposed comparatively strict requirement.
Owing to these reasons, under the situation that is applied to adopt short transmission link, use direct modulation technique in conjunction with the 1310nm laser with scattered optical fiber link of penetrating.For being applied to metropolitan area and long-distance optical fiber transmission link, the link low-loss requires to use the 1550nm laser of external modulation, crosses very long distance (100km) and high-frequency (surpassing 900MHz) usually.The limiting factor of this type of link may be the conversion from the residual phase noise of laser, and described residual phase noise converts amplitude noise to via the scattering that exists in the optical fiber link.Therefore the present invention is absorbed in the problem of the simple and low-cost system that is provided for the noise removing that is associated with the phase noise of laser, makes simulated optical output 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 the digit optical transmission system, for example dense wave division multipurpose (DWDM) system." DWDM Networks, Devices, and Technology " (IEEEPress, 2003, the 154 pages) referring to (for example) Kartalopoulos.
Except to the desired low noise figure of 1550nm simulated optical transmission system, described system also is necessary for highly linear.In the specific simulating emitter intrinsic distortion to stop linear electrical modulation signal be optical signalling by linear transformation, but cause described distorted signals.These influences are harmful especially for the multichannel video transmission, and described multichannel video transmission requires fabulous linearity in case channel is interfering with each other.The simulated optical system of highly linearization is widely used in commercial analogue system, for example broadcasts TV transmission, CATV, interactive TV and visual telephone transmission.
As alternative to direct current-modulation, the known external modulator that in optical transmission system, uses continuous wave (CW) laser in the prior art.The 5th, 699, No. 179 United States Patent (USP)s are described a kind of feedforward linearized simulated optical reflector of external modulation, and it is used to reduce compound secondary (CSO) distortion component that optical fiber brings out.
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 had is excessive for many actual embodiments.Be used for the complicated system component of linearizing feed-forward technique needs, for example luminous power combiner and a plurality of light source.The quasi-optics feed-forward technique suffers similar complexity problem, and the part that need mate fabulously in addition.Yet as discussed below, the forward direction technology that is used for the phase noise elimination is the practical technique that can use many exploitation good technical to implement.
Before the present invention, use the purpose of the phase noise component that the phase-modulator be coupled to externally modulated laser produces with the various noise sources that are used for eliminating by the semiconductor structure of laser as yet.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 are irrelevant with optical maser wavelength basically, but noise can be sentenced the different modes appearance at different wave length in the single mode fibers transmission.The main internal mechanism that causes phase place and amplitude noise is the spontaneous emission in the active region of laser.Because the photon of spontaneous emission does not have given phase relation with those photons that produce via stimulated emission, thereby the amplitude of gained light field and phase place all are affected.Spontaneous emission process is well-known, and has been shown as by the Brownian motion process description, and wherein noise spectrum is constant (white noise) basically in frequency of operation.In the laser outside, for example environmental impacts such as microphone effect, temperature fluctuation and bias current noise also can produce phase noise in light field.These incidents cause the light phase noise usually, and it represents the noise spectrum with " 1/f " correlation.
The present invention manage by feedforward eliminate minimize from the proper phase noise of semiconductor laser and no matter the driving mechanism of noise 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 that uses externally modulated laser.
Another object of the present invention is to compensate the noise of the laser that is used for optical transmission system.
A further object of the present invention is to provide a kind of external modulation 1550nm simulated optical transmission system that is used for to improve the external phase modulator that phase noise reduces.
Another purpose of the present invention is to provide a kind of and is applicable to remote dispersive optical fiber medium and uses the highly linear optical transmission system of externally modulated laser together with phase-correcting circuit that is coupled to optical signalling and phase-modulator.
Another purpose of the present invention is to provide a kind of and is used at the phase-shift circuit of the simulated optical transmission system reduction that is applicable to remote dispersive optical fiber medium from the residual phase noise of externally modulated laser.
The present invention also aims to provide the phase noise compensation process in the simulated optical transmission system of a kind of broadband.
2. inventive features
Briefly and put it briefly, the invention provides and a kind ofly be used to produce optical modulation for the optical launcher that is transferred to remote receiver via optical fiber link, it comprises: laser; Modulator, it is used for the RF signal described laser being carried out external modulation and comprises the optical signalling that contains the modulation intelligence component with generation; And phase-modulator, its output that is coupled to described modulator is to be used for eliminating the noise signal that described laser produces.
On the other hand, the invention provides and a kind ofly be used to produce optical modulation for via the optical launcher of dispersing optics link transmission to remote receiver, it has: semiconductor laser, and it is used to produce the optical signalling with the phase noise that is associated; Noise canceller circuit, it is coupled to the output of described laser and comprises the optical phase modulator that is used for reducing the phase noise that laser produces; And external modulator, it is coupled to the output of described phase-modulator and is used to receive broadband analog radio-frequency signal input and modulates described optical signalling.
On the other hand, the invention provides a kind ofly for the optical transmission system that uses via the dispersive optical fiber link, it comprises: the optical launcher with the input of analog or digital RF signal; Semiconductor laser; Modulation circuit, it is used for the described laser of external modulation; And the circuit that is used to eliminate the optical phase modulation product that the noise that produced with semiconductor laser is associated.
In another aspect of this invention, a kind of noise canceller circuit that is used for reducing in analog signal transmission phase noise is provided, it will split into two paths from the output optical signalling of the external modulator of semiconductor laser, and one leads to phase-modulator and another leads to frequency discriminator.On amplitude and phase place, adjust frequency or the phase place dependence of described phase modulated erasure signal with the phase noise of coupling laser generation.The phase place of described signal by described path one in delay or phase adjustment element synchronous.Then main and secondary signal only has amplitude-modulated single optical signalling with generation by the phase-modulator reorganization.Therefore, phase-modulator is modulated main signal from semiconductor laser in the mode that minimizes the gained phase noise, thereby makes analog signal be suitable for via the dispersive optical fiber link transmission.
According to this disclosure (comprise following be described in detail in) and, be understood by those skilled in the art that extra purpose of the present invention, advantage and novel feature by putting into practice the present invention.When hereinafter describing when of the present invention, should understand the present invention and be not limited to this referring to preferred embodiment.Can access additional application, modification and the embodiment in other field of those skilled in the art will realize that of this paper teaching, described additional application, modification and embodiment belong in the scope of the invention that discloses in this article and advocate, and the present invention can have remarkable effectiveness with respect to it.
Description of drawings
In conjunction with the drawings referring to following detailed description, will understand and more fully understand these and other feature of the present invention and advantage better, 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 according to first embodiment of optical transmission system of the present invention;
Fig. 3 is the height simplified block diagram according to second embodiment of optical transmission system of the present invention.
Statement novel feature of the present invention and characteristic in appended claims.Yet, can be in conjunction with the drawings referring to the detailed description of specific embodiment is come the best the present invention of understanding 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 is used to discern identical or intimate element, and wishes the principal character with the graphic mode explanation one exemplary embodiment of highly simplifying.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 as the 5th, 699, the block diagram of the prior art optical launcher that utilizes external modulator that No. 179 United States Patent (USP)s represent.Described reflector (usually with 10 show) via fiber path 30 to remote receiver 60 transmitting optics signals.Reflector 10 comprises semiconductor laser 12, and it produces continuous wave (CW) output.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 optics signal from laser is coupled to modulator 16 by optical fiber 14.Modulator 16 can be an above modulator in single modulator, cascade MZ modulator or for example feedforward linearized circuit of for example Mach-Zehnder modulator.Modulator 16 also receives broadband RF signal, for example Modulation and Amplitude Modulation residual sideband (AM-SDB) cable TV (CATV) or vision signal via terminal 18 and circuit 20.In addition, when using feedforward linearized circuit, provide the signal that depolarizes to modulator 16 via terminal 22 and circuit 24.The described signal that depolarizes is used at modulator 16 the optics input that arrives error correction modulator (not shown) being depolarized.
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 of several kms of extend past.In the case, can provide for example EDFA 28 line amplifiers such as grade with spacing distance therein along described circuit, so that described signal is boosted to required level.At receiver 60 places, also can provide the amplifier optical signalling that (not shown) imports into to boost.Then the signal through boosting is applied to photoelectric detector and at receiver 60 places it is carried out rectification to produce the signal of telecommunication, the described signal of telecommunication is represented the original video or the data-signal at circuit 50 places.
Fig. 2 is the block diagram that utilizes the optical launcher of external modulator according to first embodiment of the invention.Described reflector (showing with 100 usually) is transferred to remote receiver with optical signalling via fiber path 30.Reflector 100 comprises semiconductor laser 101, and it produces continuous wave (CW) output.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.
Employed edge-emission semiconductor laser distributed feedback laser (DFB) preferably in Fig. 2 system, but can use Fabry-Perot (FP) laser equally.Distributed Feedback Laser is an optimization approach, because its optics output mainly is included in the single zlasing mode, and the optical energy of FP laser is dispersed in the middle of many patterns.In a preferred embodiment, described laser is that the laser optical output wavelength is at 1530 outside cavity gas lasers that arrive in the 1570nm scope.
Unmodulated optics signal from laser splits into two parts; Modulator 102 is coupled to by optical fiber 103 in first.Modulator 102 can be an above modulator in single modulator, cascade MZ modulator or for example feedforward linearized device of for example Mach-Zehnder modulator.Modulator 102 receives the broadband RF signal or the digital signal of Modulation and Amplitude Modulation residual sideband (AM-SDB) cable TV (CATV) for example or vision signal via terminal 104 and circuit 105.Analog signal can have greater than the bandwidth of an octave and carry a plurality of channels.In addition, when using feedforward linearized device, the configuration that is similar to Fig. 1 provides the signal that depolarizes to modulator like that.The described signal that depolarizes is used at modulator 102 the optics input that arrives error correction modulator (not shown) being depolarized.
As mentioned above, the optical signalling output of laser 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 adjusting the amplitude of described signal rightly, matches with the amplitude of the phase-modulated component introduced with the phase noise feature of laser 101.
The output of attenuator 108 then is connected to phase deviation circuit 109.Circuit 109 is proofreaied and correct the time lag that the described signal with being applied directly to modulator 102 of the signal output that is applied to circuit element 107,108 is compared.In the video transmission frequency band of being paid close attention to (is 50MHz-1000MHz for traditional C ATV system), the phase noise of semiconductor laser 101 is " in vain ", i.e. the spectral power density of noise and frequency-independent.In the case, phasing path 106,107,108,109 has constant (can adjust) gain with needs, and it postpones just in time to mate with the delay of predominating path 103,102 and 110.Need an effect that the aspect is 107 pairs of signals of frequency discriminator of explanation, specifically the optics in the phasing path is to the result of electricity transfer process.When photodiode detects optical signalling, observe the phenomenon that is called shot noise.This noise is to produce with the statistic processes that produces electron-hole pair by absorb photon in photodiode.This noise is inevitable for all practical purposes.Therefore, shot noise will constitute lower limit to attainable phase noise amount of cancellation.
Then the output with phase deviation circuit 109 is applied to phase-modulator 110, with so that by its phase modulated with phasing be incorporated in the optical signalling with so that correction or noise that compensate for laser was produced.
The pectrum noise density of the photoelectric current that produces from photodiode is given as
<i
n 2>＝2eI
p
Wherein e is electron charge and I
pIt is the DC photoelectric current.The those skilled in the art will recognize such fact immediately: noise power has linear dependence to the optical power that is received, and improved along with the increase of institute's received power by the signal to noise ratio of the process of shot noise domination.This represent propose the invention in basic design tradeoff.Be switched to phasing path 106,107,108,109 ... in more power will be that cost is improved final phase noise and eliminated with the optics power output of reflector.
The output of phase-modulator 110 is coupled to amplifier 112 via optical fiber 111, and described amplifier 112 then is connected to optical fiber or link 30.At far-end, optical fiber or link 30 are connected to receiver, and described receiver is converted to the RF signal with the optical signalling that is received, and are similar among Fig. 1 to be represented.
Fig. 3 is the block diagram that utilizes the optical launcher of external modulator according to second embodiment of the invention.Described reflector (showing with 200 usually) is transferred to remote receiver with optical signalling via fiber path 30.Reflector 200 comprises semiconductor laser 101, and it produces continuous wave (CW) output.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 optics signal from laser splits into two parts; A part is coupled to phase-modulator 110 by optical fiber 103.Phase-modulator 110 is incorporated into phasing in the optical signalling, with so that correction or noise that compensate for laser was produced.Modulator 102 is coupled in the CW output of phase-modulator 110, contains the optical signalling of modulation intelligence with generation.
As indicated above, the optical signalling output of laser is split into two parts: a part is applied to phase-modulator 110; Another part is coupled to frequency discriminator circuit 107 by optical fiber 106.
The output of frequency discriminator 107 is applied to attenuator 108 adjusting the amplitude of described signal rightly, matches with the amplitude of the phase-modulated component introduced with the phase noise feature of laser 101.
The output of attenuator 108 then is connected to phase deviation circuit 109.Circuit 109 is proofreaied and correct the time lag that the described signal with being applied to phase-modulator 110 of the signal output that is applied to circuit element 107,108 is compared.In the video transmission frequency band of being paid close attention to (is 50MHz-1000MHz for traditional C ATV system), the phase noise of semiconductor laser 101 is " in vain ", i.e. the spectral power density of noise and frequency-independent.In the case, phasing path 106,107,108,109 has constant (can adjust) gain with needs, and it postpones just in time to mate with the delay of predominating path 103,102 and 110.Needing an aspect of explanation is frequency discriminator 107, and specifically the optics in the phasing path is to the electricity transfer process.When photodiode detects optical signalling, observe the phenomenon that is called shot noise.This noise is to produce with the statistic processes that produces electron-hole pair by absorb photon in photodiode.It is inevitable that this noise is actually.Therefore, shot noise will apply lower limit to attainable phase noise amount of cancellation.
Under the situation that does not break away from the spirit and scope of the present invention, it will be apparent to those skilled in the art that many changes and modification.For instance, although be described and illustrate in the context of video or multichannel TV signal modulated laser or light-emitting diode, for example the inherent distortion of 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 in the main and secondary path is in the illustrated embodiment in secondary path, but this also can be in having the predominating path of rough adjustment.Secondary path is preferred, because this type of delay in the 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 in computer product (it visibly is implemented in the machine-readable storage device for programmable processor and carries out) or go up and implement at the software that is positioned at network node or website place (its can be automatically or download to as required computer product).Aforementioned techniques can be carried out by the gate array or the hard-wired logic of (for example) single central processing unit, multiprocessor, one or more digital signal processors, gate, is used to carry out a sequence signal or instruction repertorie to carry out function of the present invention by output is operated and produced to the input data.Described method can advantageously be implemented in one or more computer programs that can carry out on programmable system, and described programmable system comprises that at least one is through being coupled to receive data and instruction from data-storage system and to launch programmable processor, at least one input/output device and at least one output device of data and instruction to data-storage system.Each computer program can be optionally implemented with advanced procedures or object oriented programming languages or with compilation or machine language; And under any circumstance, described language can be compiling or interpreter language.For instance, the suitable treatment device comprises general purpose microprocessor and special microprocessor.In general, processor will receive instruction and data from read-only memory and/or random access memory.The storage device that is suitable for visibly implementing computer program instructions and data comprises and the nonvolatile memory of form of ownership comprises: semiconductor device, for example EPROM, EEPROM and flash memory device for instance; Disk, for example internal hard drive and removable dish; Magneto optical disk; And CD-ROM dish.Any aforementioned means can be replenished or is incorporated among the ASIC by specially designed application-specific integrated circuit (ASIC) (ASIC).
To understand, each in the said elements or both or both more than also can effectively be applied to the structure of other type different with the above-mentioned type together.
Although, do not wish that it is limited to the details of being showed, because can under the situation that breaks away from spirit of the present invention never in any form, make various modifications and structural change with the present invention explanation and be described as in optical transmission system, implementing.
Do not doing under the situation about further analyzing, aforementioned content will represent main points of the present invention so comprehensively, make other people under the situation of the feature that is not omitted in the intrinsic propesties that constitutes the general or particular aspects of the present invention on the prior art position fully, to adjust being used for various application it easily, and therefore this type of is adjusted and should and wish to be included in the equivalence meaning and scope of appended claims by using current knowledge.
Claims (16)
1. one kind is used to produce the optical launcher that supplies to be transferred to via optical fiber link the optical modulation that is used to transmit of remote receiver, and it comprises:
Laser, it is used to produce the base band optical signalling of the noise expansion that comprises on the frequency spectrum;
Modulator, it is used for described optical signalling being modulated the component that contains modulation intelligence with generation with the RF signal; And
Phase-modulator, its output that is coupled to described modulator is to be used to eliminate the phase noise that is associated with described base band optical signalling and to produce output signal.
2. reflector according to claim 1, wherein said laser is a semiconductor laser, and described phase-modulator is eliminated the phase noise component in the described base band optical signalling.
3. reflector according to claim 1, wherein said RF signal is a digital signal.
4. reflector according to claim 1, wherein said modulator are the Mach-Zehnder modulators.
5. reflector according to claim 1, it further comprises the frequency discriminator circuit, described circuit has the input of the described output that is connected to described laser and is coupled to photodiode output, so that the described phase noise in the described optical signalling is converted to the modulation signal that is applied to described phase-modulator, make that effective phase noise takes place to be eliminated.
6. reflector according to claim 1, the wavelength of the light output of wherein said laser arrives in the 1570nm scope 1530.
7. reflector according to claim 1, wherein said RF signal are the broadband analog signal inputs, and it has greater than the bandwidth of an octave and comprises that a plurality of different information carry channel.
8. reflector according to claim 1, wherein said phase-modulator can optionally be adjusted according to the length of described link to compensate the distortion that described dispersive optical fiber link is produced.
9. one kind is used to produce the optical launcher that supplies to be transferred to via optical fiber link the optical modulation that is used to transmit of remote receiver, and it comprises:
Laser, it is used to produce the base band optical signalling of the noise expansion that comprises on the frequency spectrum;
Phase-modulator, its output that is coupled to described laser is to be used to eliminate the phase noise that is associated with described base band optical signalling and to produce output signal; And
Modulator, it is used for the RF signal described optical signalling being modulated, and contains the optical signalling of modulation intelligence with generation.
10. reflector according to claim 9, wherein said laser is a semiconductor laser, and described phase-modulator is eliminated the phase noise component in the described base band optical signalling.
11. reflector according to claim 9, wherein said RF signal is a digital signal.
12. reflector according to claim 9, wherein said modulator are the Mach-Zehnder modulators.
13. reflector according to claim 9, it further comprises the frequency discriminator circuit, described circuit has the input of the described output that is connected to described laser and is coupled to photodiode output, so that the described phase noise in the described optical signalling is converted to the modulation signal that is applied to described phase-modulator, make that effective phase noise takes place to be eliminated.
14. reflector according to claim 9, the wavelength of the light output of wherein said laser arrives in the 1570nm scope 1530.
15. reflector according to claim 9, wherein said RF signal are the broadband analog signal inputs, it has greater than the bandwidth of an octave and comprises that a plurality of different information carry channel.
16. reflector according to claim 9, wherein said phase-modulator can optionally be adjusted to compensate the distortion that described dispersive optical fiber link is produced according to the length of described link.
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 true CN101277154A (en) | 2008-10-01 |
| CN101277154B CN101277154B (en) | 2015-09-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| 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) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109286124A (en) * | 2018-09-18 | 2019-01-29 | 上海交通大学 | Laser linewidth compression method and system |
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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 |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060210282A1 (en) * | 2005-03-15 | 2006-09-21 | John Iannelli | Directly modulated laser optical transmission system with phase modulation |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| 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 |
-
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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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060210282A1 (en) * | 2005-03-15 | 2006-09-21 | John Iannelli | Directly modulated laser optical transmission system with phase modulation |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109286124A (en) * | 2018-09-18 | 2019-01-29 | 上海交通大学 | Laser linewidth compression method and system |
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| Publication number | Publication date |
|---|---|
| JP2008252910A (en) | 2008-10-16 |
| JP2013255264A (en) | 2013-12-19 |
| CN101277154B (en) | 2015-09-30 |
| TW200840362A (en) | 2008-10-01 |
| JP5425409B2 (en) | 2014-02-26 |
| KR20080088352A (en) | 2008-10-02 |
| JP5847771B2 (en) | 2016-01-27 |
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