CN1731708A - Method for monitoring optical signal in optical transmission system - Google Patents

Method for monitoring optical signal in optical transmission system Download PDF

Info

Publication number
CN1731708A
CN1731708A CNA2005100284358A CN200510028435A CN1731708A CN 1731708 A CN1731708 A CN 1731708A CN A2005100284358 A CNA2005100284358 A CN A2005100284358A CN 200510028435 A CN200510028435 A CN 200510028435A CN 1731708 A CN1731708 A CN 1731708A
Authority
CN
China
Prior art keywords
signal
optical
frequency
spectrum
transmission system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CNA2005100284358A
Other languages
Chinese (zh)
Other versions
CN100477562C (en
Inventor
田祥庆
苏翼凯
胡卫生
胡佩钢
何浩
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Jiaotong University
Original Assignee
Shanghai Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Jiaotong University filed Critical Shanghai Jiaotong University
Priority to CNB2005100284358A priority Critical patent/CN100477562C/en
Publication of CN1731708A publication Critical patent/CN1731708A/en
Application granted granted Critical
Publication of CN100477562C publication Critical patent/CN100477562C/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Landscapes

  • Optical Communication System (AREA)

Abstract

Disclosed is an apparatus for monitoring optical signal in optical transmission system. The communication light signal is separated into two ways by optical coupler and the two-way light signal enters into coupler after adjusting the polarization status. Local oscillation light generated by local oscillation laser goes through the polarization unit, after adjusting, enters into the coupler and is mixed with the light signal need detected; the power of mixed signal is detected and the mail control unit changes the oscillation frequency of local oscillation laser. Repeating above steps until the oscillation frequency scans the whole signal frequency spectrum. The frequency deviation is monitored by central wavelength of optical filter and signal. The invention has the advantages of simultaneously monitoring the central wave length of signal and in-band noise, and derivates the frequency deviations of signal central wave length and filter central wave length.

Description

The method of optical monitoring signal in the optical transmission system
Technical field
What the present invention relates to is a kind of method of technical field of optical fiber communication, specifically, is the method for optical monitoring signal in a kind of optical transmission system.
Background technology
In the reconfigurable optical network, each channel all will be through multiplexing, demultiplexing and route before being received, and signal is every through primary multiplexer/demodulation multiplexer, all will stand certain filter effect.In this course, spontaneous radiation (ASE) noise in the channel passband constantly accumulates, and the outer filtered device of ASE noise of channel has been restricted to lower level, therefore band power level interior and the outer ASE noise of band is different, obviously the power level of ASE noise has determined final Optical Signal To Noise Ratio (OSNR) in the band, also is signal quality.And traditional spectroanalysis instrument (OSA) based on the rotation diffraction grating structure can't be told in-band noise by right area.But people more wish to obtain more the information about signal, as signal center's wavelength, accumulation filter shape etc., by filter shape can monitor signal centre wavelength frequency drift, and these can obtain by ASE spectrum in being with.Yet traditional OSA is because the restriction of resolution (representative value 0.1nm), is difficult to detect the fine structure of 10Gb/s and following data rate signal.Owing to be subjected to realizing the restriction on the principle, can not from light signal, tell noise by right area, therefore can not monitor ASE spectrum in the band.
Find by prior art documents, Chinese patent application number is 200410082685.5, patent name is " apparatus and method of monitoring light signals ", in this method, used a polarization beam apparatus that signal is divided into two bundles, wherein a branch of power measurement that is used for, another bundle is used for the polarization state that the polarization scrambled device of FEEDBACK CONTROL changes input signal.Yet this monitoring technology only can measure OSNR, can't detect spectrum in the band.Show that more than many can not the monitoring is with interior OSNR in the prior art at present, simultaneously, also do not possess the monitoring method of ASE spectrum in the band.
Summary of the invention
The objective of the invention is to overcome deficiency of the prior art, the method for optical monitoring signal in a kind of optical transmission system is provided.Make its can be used in dynamic reconfigurable wavelength division multiplexing (WDM) optical transmission system signal spectrum and the band in (In-band) ASE spectrum, and the monitoring of the interior OSNR of band, the various defectives that prior art exists have been solved, can also carry out the monitoring of the centre wavelength of signal and in-band noise simultaneously, and the frequency drift of the accumulation optical filter shape that can derive thus and signal center's wavelength and filter center wavelength.
The method of optical monitoring signal comprises the following steps: in the optical transmission system of the present invention
1. with optical coupler the Communication ray signal is divided into two-way, wherein the light signal of smaller power part is as monitor signal;
2. light signal to be measured is admitted to the first Polarization Control unit, enters coupler behind the adjustment polarization state;
3. the local oscillations light of local oscillations laser generation enters coupler and light signal mixing to be measured through the second Polarization Control unit behind the adjustment polarization state;
4. the light signal after the mixing through Photoelectric Detection and after amplifying by the radio frequency power detector detection power;
5. main control unit is controlled the first Polarization Control unit, make its polarization state generating period variation, in one-period, the power maximum of radio frequency power detector output is corresponding to the power of light signal under a certain frequency, minimum value writes down maximum and minimum value under the corresponding frequencies corresponding to the power of ASE noise under a certain frequency in the band;
6. change the frequency of oscillation of local oscillations laser by main control unit;
7. repeating step 2.-6., until the inswept whole signal spectrum of the frequency of oscillation of local oscillations laser;
8. 7., obtain ASE spectrum and optical filter shape in the band by step, and the centre frequency of signal spectrum and signal, signal bandwidth;
9. by the frequency drift of the centre wavelength monitor signal of optical filter centre wavelength and signal.
ASE spectrum in the described band obtains being with interior ASE spectrum by corresponding power minimum point.
ASE spectrum in the described band obtains the optical filter shape by ASE spectrum in the band, comprises optical filter centre wavelength, and sideband rises and falls.
Described signal spectrum obtains signal spectrum by the power maximum of points.
Described signal spectrum is by the centre frequency of signal spectrum picked up signal, signal bandwidth.
Described signal spectrum obtains being with interior OSNR by ASE spectrum integral union in signal spectrum and the band; Computing formula is: OSNR = 10 log ( 2 ∫ f ( P max E - P min E ) ∫ f P min E ) , P wherein Max EBe the maximum that the radio-frequency power detecting unit measures, P Min EBe the minimum value that the radio-frequency power detecting unit measures, ∫ f() is illustrated in the frequency domain upper integral.
When this method was used for the fiber optic transmission system signal monitoring, wherein first, second Polarization Control unit required to support FEEDBACK CONTROL, can adopt GP MPC-4X.The local oscillations laser requires wavelength adjustable continuously, and must can adopt Anritsu MG9638A for narrow band laser (representative value 300kHz-20MHz).4. middle flashlight of step and local oscillator light are by the coupler mixing, and coupler is four port devices.The Photoelectric Detection of step in 4. must adopt low bandwidth (representative value DC-155MHz) balanced detector, comprises the PIN pipe of two symmetries.The radio-frequency power detecting unit must be narrowband device (representative value DC-155MHz), and supports measurement programming, can adopt HP 8594E.
The present invention measures the principle of OSNR:
Under a certain light frequency,, when the light signal to be measured that their are exported is vertical mutually with the local oscillations polarized state of light, be by the detected electrical power of radio frequency power detector when adjusting the first and second Polarization Control unit:
P min E = K · 1 2 P ASE - - - ( 1 )
P wherein ASEBe whole ASE power, K is a proportionality coefficient.This moment corresponding minimum point
When light signal to be measured and the local oscillations polarized state of light of their output is vertical mutually, be by the detected electrical power of radio frequency power detector:
P max E = K · ( P S + 1 2 P ASE ) - - - ( 2 )
P wherein SBe signal power.This moment corresponding maximum of points.
Make it frequency sweep by main control unit control local oscillator, repeat above process.As shown in Figure 2.OSNR is obtained by following formula:
OSNR = 10 log ( 2 ∫ f ( P max E - P min E ) ∫ f P min E ) - - - ( 3 )
∫ wherein f() is illustrated in the frequency domain upper integral.
The present invention is applicable to the interior ASE spectrum of Optical Signal To Noise Ratio (OSNR), band of fiber optic transmission system and the measurement of frequency drift, by the polarization state and the heterodyne system detection of control measured signal, obtains the distribute power of the interior ASE noise of band.Simultaneously, because the narrow linewidth characteristic of measuring process, this method is insensitive for polarization mode dispersion (PMD).This method is applicable to single wavelength, multi-wavelength and multichannel different fiber communication system.
Embodiment
Embodiment
1. with optical coupler the Communication ray signal is divided into two-way, wherein the light signal of smaller power part is as monitor signal.
2. light signal to be measured is admitted to the first Polarization Control unit, and the Polarization Control unit is used to adjust the signal polarized state of light, can adopt GP MPC-4X in application, must support dynamical feedback control.Flashlight enters coupler after adjusting polarization state.
3. the local oscillations light of local oscillations laser generation is sent into the second Polarization Control unit, and the functional description of the second Polarization Control unit and specification requirement are with the first Polarization Control unit.The local oscillator laser is a narrow-band light source, and representative value is 300kHz-20MHz, can adopt Anritsu MG9638A.
4. local oscillator light enters coupler after adjusting polarization state, with light signal mixing to be measured; Coupler is four port devices herein, comprises two input ports and two output ports, along separate routes than being 50: 50.
5. the light signal after the mixing is sent into photoelectric detector, requires to use the balance photoelectric detector in this method, and it comprises the PIN pipe of two symmetries.Bandwidth requirement to the balance photoelectric detector is DC-155MHz.
6. the signal of telecommunication of photoelectric detector output is sent into the radio frequency power detector detector after amplifying, to detect Beat Signal power.Radio frequency power detector must be supported measurement programming, can adopt HP 8594E.The measurement bandwidth of radio frequency power detector is DC-155MHz.
7. main control unit is controlled the first Polarization Control unit, makes its polarization state generating period variation.In one-period, the power maximum of radio frequency power detector output is corresponding to the power of light signal under a certain frequency, and minimum value writes down maximum and minimum value under the corresponding frequencies corresponding to the power of ASE noise under a certain frequency in the band.
8. after the measurement under a certain frequency is finished, change the frequency of oscillation of local oscillations laser by main control unit, repeating step 2.-7., until the inswept whole signal spectrum of the frequency of oscillation of local oscillations laser;
9. 8., obtain ASE spectrum and optical filter shape in the band by step, and the centre frequency of signal spectrum and signal, signal bandwidth; Calculate OSNR in the band by formula 3.
10. by the frequency drift of the centre wavelength monitor signal of optical filter centre wavelength and signal.
By this method, can be directly in signal receiving end is measured band OSNR, be with in ASE spectrum and optical filter shape, and the centre frequency of signal spectrum and signal, signal bandwidth.In addition, adopt this method can also obtain high resolution and accuracy.Measure in the example of OSNR using the present invention, can in 16～30dB scope, record accurately OSNR in the band.In an example of the frequency drift of the centre wavelength monitor signal of using measuring light filter center wavelength of the present invention and signal, the frequency drift that the present invention records is 0.073nm, and be 0.070nm with the frequency drift that OSA records, the present invention has shown high resolution.It is emphasized that and use the measurement result of OSA when turning off data-signal, to obtain, do not allow in the actual transmissions system to do like this; And use the present invention can directly record frequency drift.

Claims (10)

1, the method for optical monitoring signal in a kind of optical transmission system is characterized in that, may further comprise the steps:
1. with optical coupler the Communication ray signal is divided into two-way, wherein the light signal of smaller power part is as monitor signal;
2. light signal to be measured is admitted to the first Polarization Control unit, enters coupler behind the adjustment polarization state;
3. the local oscillations light of local oscillations laser generation enters coupler and light signal mixing to be measured through the second Polarization Control unit behind the adjustment polarization state;
4. the light signal after the mixing through Photoelectric Detection and after amplifying by the radio frequency power detector detection power;
5. main control unit is controlled the first Polarization Control unit, make its polarization state generating period variation, in one-period, the power maximum of radio frequency power detector output is corresponding to the power of light signal under a certain frequency, minimum value writes down maximum and minimum value under the corresponding frequencies corresponding to the power of ASE noise under a certain frequency in the band;
6. change the frequency of oscillation of local oscillations laser by main control unit;
7. repeating step 2.-6., until the inswept whole signal spectrum of the frequency of oscillation of local oscillations laser;
8. 7., obtain ASE spectrum and optical filter shape in the band by step, and the centre frequency of signal spectrum and signal, signal bandwidth;
9. by the frequency drift of the centre wavelength monitor signal of optical filter centre wavelength and signal.
2, the method for optical monitoring signal in the optical transmission system according to claim 1 is characterized in that, ASE spectrum in the described band obtains being with interior ASE spectrum by corresponding power minimum point.
3, the method for optical monitoring signal in the optical transmission system according to claim 1 and 2 is characterized in that, ASE spectrum in the described band obtains the optical filter shape by ASE spectrum in the band, comprises optical filter centre wavelength, and sideband rises and falls.
4, the method for optical monitoring signal in the optical transmission system according to claim 1 is characterized in that, described signal spectrum obtains being with interior OSNR by ASE spectrum integral union in signal spectrum and the band; Computing formula is: OSNR = 10 log ( 2 ∫ f ( P max E - P min E ) ∫ f P min E ) , P wherein MaxEBe the maximum that the radio-frequency power detecting unit measures, P Min EBe the minimum value that the radio-frequency power detecting unit measures, ∫ f() is illustrated in the frequency domain upper integral.
5, according to the method for optical monitoring signal in claim 1 or the 4 described optical transmission systems, it is characterized in that described signal spectrum obtains signal spectrum by the power maximum of points.
6, according to the method for optical monitoring signal in claim 1 or the 4 or 5 described optical transmission systems, it is characterized in that described signal spectrum is by the centre frequency of signal spectrum picked up signal, signal bandwidth.
7, the method for optical monitoring signal in the optical transmission system according to claim 1 is characterized in that, FEEDBACK CONTROL is supported in described Polarization Control unit.
8, the method for optical monitoring signal in the optical transmission system according to claim 1 is characterized in that, described local oscillations laser, and wavelength is adjustable continuously, and must be narrow band laser.
9, the method for optical monitoring signal in the optical transmission system according to claim 1 is characterized in that, described Photoelectric Detection must be the low bandwidth balanced detector, comprises the PIN pipe of two symmetries.
10, the method for optical monitoring signal in the optical transmission system according to claim 4 is characterized in that, described radio-frequency power detecting unit must be narrowband device, and supports measurement programming.
CNB2005100284358A 2005-08-04 2005-08-04 Method for monitoring optical signal in optical transmission system Expired - Fee Related CN100477562C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CNB2005100284358A CN100477562C (en) 2005-08-04 2005-08-04 Method for monitoring optical signal in optical transmission system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CNB2005100284358A CN100477562C (en) 2005-08-04 2005-08-04 Method for monitoring optical signal in optical transmission system

Publications (2)

Publication Number Publication Date
CN1731708A true CN1731708A (en) 2006-02-08
CN100477562C CN100477562C (en) 2009-04-08

Family

ID=35964019

Family Applications (1)

Application Number Title Priority Date Filing Date
CNB2005100284358A Expired - Fee Related CN100477562C (en) 2005-08-04 2005-08-04 Method for monitoring optical signal in optical transmission system

Country Status (1)

Country Link
CN (1) CN100477562C (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102714544A (en) * 2010-02-15 2012-10-03 爱斯福公司 Reference-based in-band OSNR measurement on polarization-multiplexed signals
CN101605276B (en) * 2008-06-13 2013-04-24 华为技术有限公司 Method and device for transmitting optical signals
CN103370890A (en) * 2011-02-18 2013-10-23 爱斯福公司 Characterization of non-ASE noise on optical signals
CN104363048B (en) * 2014-10-24 2017-04-12 华中科技大学 Coherent mixing based in-band optical signal to noise ratio monitoring method and calculation system
WO2018010058A1 (en) * 2016-07-11 2018-01-18 华为技术有限公司 Spectrum detection device and method
CN109460560A (en) * 2018-06-27 2019-03-12 上海理工大学 A kind of ultrafast imaging system noise model method for building up based on balance detection
CN118041422A (en) * 2024-01-25 2024-05-14 北京融为科技有限公司 Optical fiber filter wavelength control method and system for satellite-to-ground laser communication

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101605276B (en) * 2008-06-13 2013-04-24 华为技术有限公司 Method and device for transmitting optical signals
CN102714544A (en) * 2010-02-15 2012-10-03 爱斯福公司 Reference-based in-band OSNR measurement on polarization-multiplexed signals
US9112604B2 (en) 2010-02-15 2015-08-18 Exfo Inc. Reference-based in-band OSNR measurement on polarization-multiplexed signals
CN102714544B (en) * 2010-02-15 2016-08-03 爱斯福公司 Determine the method and apparatus of band noise parameter and determine the method for OSNR
CN103370890A (en) * 2011-02-18 2013-10-23 爱斯福公司 Characterization of non-ASE noise on optical signals
CN103370890B (en) * 2011-02-18 2017-03-01 爱斯福公司 The sign of non-ASE noise on optical signal
CN104363048B (en) * 2014-10-24 2017-04-12 华中科技大学 Coherent mixing based in-band optical signal to noise ratio monitoring method and calculation system
WO2018010058A1 (en) * 2016-07-11 2018-01-18 华为技术有限公司 Spectrum detection device and method
CN109478929A (en) * 2016-07-11 2019-03-15 华为技术有限公司 A kind of frequency spectrum detection device and detection method
CN109460560A (en) * 2018-06-27 2019-03-12 上海理工大学 A kind of ultrafast imaging system noise model method for building up based on balance detection
CN109460560B (en) * 2018-06-27 2023-06-30 上海理工大学 Ultra-fast imaging system noise model building method based on balance detection
CN118041422A (en) * 2024-01-25 2024-05-14 北京融为科技有限公司 Optical fiber filter wavelength control method and system for satellite-to-ground laser communication

Also Published As

Publication number Publication date
CN100477562C (en) 2009-04-08

Similar Documents

Publication Publication Date Title
US7756369B2 (en) OSNR monitoring apparatus and method using polarization splitting
US7149428B2 (en) OSNR monitoring method and apparatus using tunable optical bandpass filter and polarization nulling method
CN1731708A (en) Method for monitoring optical signal in optical transmission system
KR100295810B1 (en) Wavelength Division Multiplexing Optical Network Channel Monitoring System
EP1587225B1 (en) Method and apparatus for measuring frequency-resolved states of polarization of a working optical channel using polarisation-scrambled heterodyning
US6088144A (en) Detection of frequency-modulated tones in electromagnetic signals
US20030161631A1 (en) Optical channel monitor device and method
KR100414456B1 (en) Apparatus and method for monitoring polarization mode dispersion and chromatic dispersion in optical network
KR100431195B1 (en) A multi wavelength locking method and apparatus by using acousto-optic tunable filter
KR100501541B1 (en) Apparatus for monitoring optical signal-to-noise ratio of the optical signal
US20040156038A1 (en) Method and apparatus for providing real-time chromatic dispersion measurement
EP1443685B1 (en) Method and apparatus for monitoring channel performance in dense wavelength division multiplexed (DWDM) optical networks
CN1235365C (en) Apparatus and method for simultaneous channel and optical signal-to-noise ratio monitoring
US6941081B2 (en) Method and apparatus for polarization measurements
CN100435497C (en) Device for monitoring optical signal in optical transmission system
US20030111998A1 (en) Apparatus and method for measuring polarization-dependent loss using repeated high speed polarization scrambling
US7068944B2 (en) Multi-function optical performance monitor
ITMI20010443A1 (en) METHOD AND APPARATUS FOR THE DETECTION AND COMPENSATION OF PMD PARAMETERS IN SIGNALS LONG TRANSMITTED CONNECTIONS TO FIBER OPTICS AND SYSTEMS
JP2003517732A (en) Method and apparatus for locking the wavelength of an optical signal
US20020167670A1 (en) Method and system for optical spectrum analysis with non-uniform sweep rate correction
US6633371B1 (en) Optical performance monitors
CA2351966A1 (en) Method and apparatus for polarization measurements
DE602004006468T2 (en) Optical wavelength monitor system
US20030067641A1 (en) Apparatus and methods for polarization measurements across a spectral range
CN1790949A (en) Optical signal-to-noise ratio monitoring device in synchronous optical transmission system

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
C17 Cessation of patent right
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20090408

Termination date: 20110804