CN104363048A - Coherent mixing based in-band optical signal to noise ratio monitoring method and calculation system - Google Patents

Abstract

The invention relates to the field of communication, and discloses a coherent mixing based in-band optical signal to noise ratio monitoring method and an optical signal to noise ratio calculation system. The method is applied to the optical signal to noise ratio calculation system which comprises a polarization controller, an intrinsic laser, a coupler, a balanced detector, an electrodynamic meter and an optical signal to noise ratio calculator, and the input end of the polarization controller receives signal light. The method includes that wavelength of a to-be-tested channel is controlled to be identical to that of intrinsic light generated by the intrinsic laser; a first power value and a second power value are obtained by detection of the electrodynamic meter and are sent to the optical signal to noise ratio calculator, wherein the first power value is a power value detected by the electrodynamic meter when the signal light is equal to the intrinsic light in polarization state, and the second power value is a power value detected by the electrodynamic meter when the polarization state of the signal light is perpendicular to the polarization state of the intrinsic light; the optical signal to noise ratio calculator acquires an optical signal to noise ratio in the to-be-tested channel by calculating through the first power value and the second power value.

Description

A kind of based on OSNR Monitoring Method and computing system in the band of relevant mixing

Technical field

The present invention relates to the communications field, particularly relate to a kind of based on OSNR Monitoring Method and computing system in the band of relevant mixing.

Background technology

Along with the requirement of people to bandwidth is more and more higher, optical communication backbone network single channel rate by 40Gb/s to 100Gb/s and above speed evolution, wavelength division multiplexing (WDM:Wavelength Division Multiplexing) system wavelength interval also by 50GHz to 25GHz even 12.5GHz evolution.When wavelength interval is very little, traditional linear interpolation method cannot noise power between Measurement channel, also just cannot noise power in matching band.And along with the introducing of optical add/drop multiplexer (ROADM:optical add-drop multiplexer), the signal of different passage can through different links, be equivalent to through different filter effects, the spontaneous amplification radiated noise (ASE:amplified spontaneous emission) in being with is caused constantly to be accumulated like this, and the outer ASE of band is in reduced levels because filter limits, therefore the ASE noise of band and out-of-band is not identical, be inaccurate by the method for the measurement Optical Signal To Noise Ratio (OSNR:Optical Signal Noise Ratio) of out-of-band noise matching in-band noise.In addition, along with the use of Reconfigurable Optical Add/drop Multiplexer, add a large amount of optical filters, the filtered suppression of the noise outside signal, be less than the in-band noise existing for actual signal wavelength location, cause utilizing the method for the in-band noise of the noise calculation signal of interchannel no longer accurate.And along with the raising of signal rate, the spectrum width of signal also can increase, when spectrum width is close to channel spacing, during matching out-of-band noise, a part of signal as noise, comparatively big error can be produced.

And if adopt traditional palarization multiplexing return-to-zero method calculate band in OSNR, it mainly needs to use polarization beam apparatus, Polarization Controller and balanced detector, by regulating Polarization Controller identical by two output Output optical power of polarization beam apparatus, then OSNR is calculated again after being converted into Electric signal processing by balanced detector, because needs additionally adopt polarization beam apparatus and high speed detector, so have the higher technical problem of cost.

Summary of the invention

The invention provides a kind of based on OSNR Monitoring Method and computing system in the band of relevant mixing, to solve in prior art for the not accurate enough or technical problem that cost is higher during high speed signal measurement OSNR.

First aspect, the embodiment of the present invention provides a kind of and it is characterized in that based on OSNR Monitoring Method in the band of relevant mixing, and described method is applied in Optical Signal To Noise Ratio computing system, described system comprises: Polarization Controller, the input access flashlight of described Polarization Controller; Intrinsic laser device; Coupler, the first input end of described coupler is connected to the output of described Polarization Controller, and the second input of described coupler is connected to the output of described intrinsic laser device; Balanced detector, is connected to described coupler; Electrodymamometer, is connected to described balanced detector; Optical Signal To Noise Ratio calculator, is connected to described electrodymamometer; Described method comprises:

The wavelength controlling the flashlight of channel to be measured is identical with the wavelength of the intrinsic light that described intrinsic laser device produces;

Acquisition first performance number and the second performance number is detected by described electrodymamometer, and described first performance number and described second performance number are sent to described Optical Signal To Noise Ratio calculator, wherein, described first performance number for described flashlight identical with described intrinsic polarisation of light state time the described electrodymamometer performance number that detects, described second performance number be described flashlight vertical with described intrinsic polarisation of light state time, the performance number that described electrodymamometer detects;

Described Optical Signal To Noise Ratio calculator calculates by described first performance number and described second performance number the Optical Signal To Noise Ratio obtained in described channel to be measured.

Optionally, described Optical Signal To Noise Ratio calculator obtains described Optical Signal To Noise Ratio by following formulae discovery:

$\mathrm{OSNR}=10\lg \frac{P_s}{P_n}\&CenterDot;\frac{B_r}{B_n}=10\lg {\left(\frac{<I_{\max }\left(t\right)>-<I_{\min }\left(t\right)>}{2<I_{\min }\left(t\right)>}\right)}^2+10\lg \frac{B_r}{B_n}$

Wherein, OSNR represents Optical Signal To Noise Ratio;

Ps representation signal power;

P _nrepresent noise power;

B _rrepresent the effective bandwidth of described channel to be measured;

B _nnoise equivalent bandwidth;

<I _maxt () > represents the first performance number;

<I _mint () > represents the second performance number.

Optionally, described by described electrodymamometer detection acquisition first performance number and the second performance number, specifically comprise:

Control described flashlight identical with described intrinsic polarisation of light state, and detect described first performance number of acquisition by described electrodymamometer;

Control described flashlight vertical with described intrinsic polarisation of light state, and detect acquisition second performance number by described electrodymamometer.

Optionally, described by described electrodymamometer detection acquisition first performance number with by described second performance number of described electrodymamometer detection acquisition, specifically comprise:

The polarization state of N the described Polarization Controller of adjustment, and then detect the N number of performance number of acquisition by described electrodymamometer, N be more than or equal to 2 positive integer;

Determine that the highest performance number is described first performance number from described N number of performance number;

Determine that minimum performance number is described second performance number from described N number of performance number.

Optionally, before the wavelength of the flashlight of described control channel to be measured is identical with the wavelength of the intrinsic light that described intrinsic laser device produces, described method also comprises:

From multiple channel, select described channel to be measured, described flashlight is by the flashlight of described transmission to be measured.

Second aspect, the embodiment of the present invention provides a kind of Optical Signal To Noise Ratio computing system, comprising:

Polarization Controller, the input access flashlight of described Polarization Controller, described Polarization Controller is for changing the polarization state of described flashlight;

Intrinsic laser device, described intrinsic laser device is for generation of intrinsic light;

Coupler, the first input end of described coupler is connected to the output of described Polarization Controller, and the second input of described coupler is connected to the output of described intrinsic laser device, and described coupler is used for carrying out mixing to described flashlight and described intrinsic light;

Balanced detector, is connected to described coupler, and described balanced detector is used for the light signal of the described balanced detector of input to be converted to the signal of telecommunication, and removes the direct current signal in the described signal of telecommunication;

Electrodymamometer, be connected to described balanced detector, for detecting acquisition first performance number and the second performance number, wherein, described first performance number for described flashlight identical with described intrinsic polarisation of light state time the described electrodymamometer performance number that detects, described second performance number be described flashlight vertical with described intrinsic polarisation of light state time, the performance number that described electrodymamometer detects;

Optical Signal To Noise Ratio calculator, is connected to described electrodymamometer, for obtaining described first performance number and described second performance number from described electrodymamometer, and calculates by described first performance number and described second performance number the Optical Signal To Noise Ratio obtained in described channel to be measured.

Optionally, described Optical Signal To Noise Ratio calculator is specifically for obtaining described Optical Signal To Noise Ratio by following formulae discovery:

$\mathrm{OSNR}=10\lg \frac{P_s}{P_n}\&CenterDot;\frac{B_r}{B_n}=10\lg {\left(\frac{<I_{\max }\left(t\right)>-<I_{\min }\left(t\right)>}{2<I_{\min }\left(t\right)>}\right)}^2+10\lg \frac{B_r}{B_n}$

Wherein, OSNR represents Optical Signal To Noise Ratio;

Ps representation signal power;

P _nrepresent noise power;

B _rrepresent the effective bandwidth of described channel to be measured;

B _nnoise equivalent bandwidth;

<I _maxt () > represents the first performance number;

<I _mint () > represents the second performance number.

Optionally, described electrodymamometer specifically for:

When described flashlight is identical with described intrinsic polarisation of light state, detects and obtain described first performance number;

When described flashlight is vertical with described intrinsic polarisation of light state, detects and obtain described second performance number.

Optionally, described electrodymamometer specifically for:

By N adjustment of the polarization state of described Polarization Controller, detect and obtain N number of performance number, N be more than or equal to 2 positive integer;

Determine that the highest performance number is described first performance number from described N number of performance number;

Determine that minimum performance number is described second performance number from described N number of performance number.

Optionally, described system also comprises:

Regulate filter, for selecting described channel to be measured from multiple channel, described flashlight is by the flashlight of described transmission to be measured.

Beneficial effect of the present invention is as follows:

Due in embodiments of the present invention, provide that a kind of method is applied in Optical Signal To Noise Ratio computing system, and system comprises: Polarization Controller based on OSNR Monitoring Method in the band of relevant mixing, the input access flashlight of Polarization Controller; Intrinsic laser device; Coupler, the first input end of coupler is connected to the output of Polarization Controller, and the second input of coupler is connected to the output of intrinsic laser device; Balanced detector, is connected to coupler; Electrodymamometer, is connected to balanced detector; Optical Signal To Noise Ratio calculator, is connected to electrodymamometer; Method comprises: the wavelength controlling the flashlight of channel to be measured is identical with the wavelength of the intrinsic light that intrinsic laser device produces; Acquisition first performance number and the second performance number is detected by electrodymamometer, and the first performance number and the second performance number are sent to Optical Signal To Noise Ratio calculator, wherein, first performance number for flashlight identical with intrinsic polarisation of light state time the electrodymamometer performance number that detects, second performance number be flashlight vertical with intrinsic polarisation of light state time, the performance number that electrodymamometer detects; Optical Signal To Noise Ratio calculator calculates by the first performance number and the second performance number the Optical Signal To Noise Ratio obtained in channel to be measured.Also namely in such scheme, by changing the polarization state of flashlight, when with intrinsic photomixing, utilize the polarization characteristic that signal is different with noise, export response by the difference of balanced detector after mixing and measure OSNR, what the program was directly measured is the noise being with interior central wavelength, so can not exist by error existing during out-of-band noise matching in-band noise, and then can improve the accuracy of OSNR in detection zone; And the impact of optical filter can not be subject to, and then further improve accuracy;

And compared to traditional palarization multiplexing return-to-zero method, the method can perfectly combine with present coherent detection system, and does not need extra polarization beam apparatus, and then has the technique effect reduced costs.

Accompanying drawing explanation

Fig. 1 is the structure chart of Optical Signal To Noise Ratio computing system in the embodiment of the present invention;

Fig. 2 is the flow chart based on OSNR Monitoring Method in the band of relevant mixing in the embodiment of the present invention;

Fig. 3 embodiment of the present invention is based on the flow chart determining the first kind of way of the first performance number and the second performance number in OSNR Monitoring Method in the band of relevant mixing;

Fig. 4 embodiment of the present invention is based on the flow chart determining the second way of the first performance number and the second performance number in OSNR Monitoring Method in the band of relevant mixing;

Fig. 5 is the structure chart of CO-OFDM system in the embodiment of the present invention one;

Fig. 6 for the calculated value of the determined OSNR of CO-OFDM system introduced based on embodiment one in the embodiment of the present invention two with contrast figure between standard value;

The error schematic diagram of the calculated value of CO-OFDM system determined OSNR of Fig. 7 for introducing based on embodiment one in the embodiment of the present invention two.

Embodiment

The invention provides a kind of based on OSNR Monitoring Method and computing system in the band of relevant mixing, practical operation the difficulty comparatively large or technical problem that cost is higher when measuring OSNR for high speed signal to solve in prior art.

Embodiment of the present invention general thought is as follows:

Due in embodiments of the present invention, provide that a kind of method is applied in Optical Signal To Noise Ratio computing system, and system comprises: Polarization Controller based on OSNR Monitoring Method in the band of relevant mixing, the input access flashlight of Polarization Controller; Intrinsic laser device; Coupler, the first input end of coupler is connected to the output of Polarization Controller, and the second input of coupler is connected to the output of intrinsic laser device; Balanced detector, is connected to coupler; Electrodymamometer, is connected to balanced detector; Optical Signal To Noise Ratio calculator, is connected to electrodymamometer; Method comprises: the wavelength controlling the flashlight of channel to be measured is identical with the wavelength of the intrinsic light that intrinsic laser device produces; Acquisition first performance number and the second performance number is detected by electrodymamometer, and the first performance number and the second performance number are sent to Optical Signal To Noise Ratio calculator, wherein, first performance number for flashlight identical with intrinsic polarisation of light state time the electrodymamometer performance number that detects, second performance number be flashlight vertical with intrinsic polarisation of light state time, the performance number that electrodymamometer detects; Optical Signal To Noise Ratio calculator calculates by the first performance number and the second performance number the Optical Signal To Noise Ratio obtained in channel to be measured.Also namely in such scheme, by changing the polarization state of flashlight, when with intrinsic photomixing, utilize the polarization characteristic that signal is different with noise, export response by the difference of balanced detector after mixing and measure OSNR, what the program was directly measured is the noise being with interior central wavelength, so can not exist by error existing during out-of-band noise matching in-band noise, and then can improve the accuracy of OSNR in detection zone; And the impact of optical filter can not be subject to, and then further improve accuracy;

And compared to traditional palarization multiplexing return-to-zero method, the method can perfectly combine with present coherent detection system, and does not need extra polarization beam apparatus, and then has the technique effect reduced costs.

In order to better understand technique scheme, below by accompanying drawing and specific embodiment, technical solution of the present invention is described in detail, the specific features being to be understood that in the embodiment of the present invention and embodiment is the detailed description to technical solution of the present invention, instead of the restriction to technical solution of the present invention, when not conflicting, the technical characteristic in the embodiment of the present invention and embodiment can combine mutually.

First aspect, the embodiment of the present invention provides a kind of based on OSNR Monitoring Method in the band of relevant mixing, the method is applied in Optical Signal To Noise Ratio computing system, this system is such as: coherent light ofdm system (CO-OFDM:Coherent Optical Orthogonal Frequency Division Multiplexing), wdm system etc., please refer to Fig. 1, this system comprises:

Polarization Controller 10, the input access flashlight of Polarization Controller, for changing the polarization state of flashlight;

Intrinsic laser device 11, intrinsic laser device 11 is for generation of intrinsic light;

Coupler 12, the first input end of coupler 12 is connected to the output of Polarization Controller 10, second input of coupler 12 is connected to the output of intrinsic laser device 11, and coupler 12 is for carrying out mixing to flashlight and intrinsic light, and coupler 12 is such as: 2 × 2 couplers of 50:50;

Balanced detector 13, is connected to coupler 12, and balanced detector 13 for the light signal of input balanced detector 13 is converted to the signal of telecommunication, and removes the direct current signal in the signal of telecommunication;

Electrodymamometer 14, is connected to balanced detector 13;

Optical Signal To Noise Ratio calculator 15, is connected to electrodymamometer 14;

Please refer to Fig. 2, method comprises the following steps:

Step S201: the wavelength controlling the flashlight of channel to be measured is identical with the wavelength of the intrinsic light that intrinsic laser device 11 produces;

Step S202: detect acquisition first performance number and the second performance number by electrodymamometer 14, and the first performance number and the second performance number are sent to Optical Signal To Noise Ratio calculator 15, wherein, first performance number for flashlight identical with intrinsic polarisation of light state time electrodymamometer 14 performance number that detects, second performance number be flashlight vertical with intrinsic polarisation of light state time, the performance number that electrodymamometer 14 detects;

Step S203: Optical Signal To Noise Ratio calculator 15 calculates by the first performance number and the second performance number the Optical Signal To Noise Ratio obtained in channel to be measured.

In specific implementation process, can pass through to control the frequency of the intrinsic light that intrinsic laser device 11 produces, and then it is identical with the wavelength of flashlight to control intrinsic light.

In specific implementation process, in step S202, electrodymamometer 14 can obtain the first performance number and the second performance number in several ways, and two kinds of enumerating below are wherein introduced, and certainly, in specific implementation process, is not limited to following two kinds of situations.

The first, detect acquisition first performance number and the second performance number by electrodymamometer 14, please refer to Fig. 3, specifically comprise:

Step S301: control signal light is identical with intrinsic polarisation of light state, and detect acquisition first performance number by electrodymamometer 14;

Step S302: control signal light is vertical with intrinsic polarisation of light state, and detect acquisition second performance number by electrodymamometer 14.

In specific implementation process, the intrinsic polarisation of light state of intrinsic laser device 11 is determined, so in step S301, after Polarization Controller 10 receives flashlight, can first detection signal polarisation of light state, then the polarization state of flashlight and intrinsic polarisation of light state are compared, and then determine the controling parameters of Polarization Controller 10, to make flashlight after Polarization Controller 10, the polarization state of flashlight is identical with intrinsic polarisation of light state.

Under normal circumstances, calculate the power that acquisition first performance number comprises signal and half noise in bandwidth, specific as follows:

$<I_{\max }\left(t\right)>2R=\sqrt{P_s{P}_{\mathrm{LO}}}+R\sqrt{P_n{P}_{\mathrm{LO}}}\&CenterDot;\&CenterDot;\&CenterDot;\left[1\right]$

Wherein, I _maxt () represents the first performance number;

R represents the responsiveness of balanced detector 13;

Ps representation signal power;

P _lOrepresent intrinsic luminous power;

P _nrepresent noise power.

In step S302, after Polarization Controller 10 receives flashlight, equally can first detection signal polarisation of light state, and then the polarization state of flashlight determines the controling parameters of Polarization Controller 10, to make flashlight after Polarization Controller 10, the polarization state of flashlight is vertical with intrinsic polarisation of light state.

Under normal circumstances, the second performance number obtained comprises the power of half noise in balanced detector 13 bandwidth, specific as follows:

$<I_{\min }\left(t\right)>=R\sqrt{P_n{P}_{\mathrm{LO}}}\&CenterDot;\&CenterDot;\&CenterDot;\left[2\right]$

Due in such scheme, electrodymamometer 14 only needs detection just can determine the first performance number and the second performance number accurately twice, so decrease the detection number of times of electrodymamometer 14, thus reduces the processing load of system.

The second, detects acquisition first performance number by electrodymamometer 14 and detects acquisition second performance number by electrodymamometer 14, please refer to Fig. 4, specifically comprise:

The polarization state of step S401:N time adjustment Polarization Controller 10, and then detected by electrodymamometer 14 and obtain N number of performance number, N be more than or equal to 2 positive integer;

Step S402: determine that the highest performance number is the first performance number from N number of performance number;

Step S403: determine that minimum performance number is the second performance number from N number of performance number.

In step S401, N can be 2,4,10 etc., and wherein, the value of N is higher, and determined first performance number is then more accurate.

In step S402 and step S403, a comparator can be set, and then be compared by this comparator and determine that the highest performance number is the first performance number, determine that minimum performance number is the second performance number by this comparator.

Due in such scheme, after flashlight enters Polarization Controller 10, do not need detection signal polarisation of light state, just can determine the first performance number and the second performance number, so reduce implementation complexity.

In specific implementation process, in step S203, Optical Signal To Noise Ratio calculator 15 obtains Optical Signal To Noise Ratio by following formulae discovery:

$\mathrm{OSNR}=10\lg \frac{P_s}{P_n}\&CenterDot;\frac{B_r}{B_n}=10\lg {\left(\frac{<I_{\max }\left(t\right)>-<I_{\min }\left(t\right)>}{2<I_{\min }\left(t\right)>}\right)}^2+10\lg \frac{B_r}{B_n}\&CenterDot;\&CenterDot;\&CenterDot;\left[3\right]$

Wherein, OSNR represents Optical Signal To Noise Ratio;

Ps representation signal power;

P _nrepresent noise power;

B _rrepresent the effective bandwidth of channel to be measured;

B _nnoise equivalent bandwidth;

<I _maxt () > represents the first performance number;

<I _mint () > represents the second performance number.

As further preferred embodiment, before the wavelength of the flashlight controlling channel to be measured is identical with the wavelength of the intrinsic light that intrinsic laser device 11 produces, method also comprises:

From multiple channel, select channel to be measured, flashlight is by the flashlight of transmission to be measured.

In specific implementation process, some systems only comprise a channel (such as: CO-OFDM system), in this case, directly receive flashlight by this channel; Some systems can comprise multiple channel (such as: WDM), in this case, then first need to select channel to be measured from multiple channel, then obtain flashlight from channel to be measured, such as: from multiple channel, select channel to be measured by regulating filter.

Further, frequency spectrum due to the signal of CO-OFDM is smooth, low speed detector can be utilized to detect the signal power at low frequency place, and then utilize signal spectrum this feature smooth to extrapolate the power of signal in whole frequency spectrum, so the frequency spectrum characteristic for CO-OFDM system only needs the balanced detector utilizing low speed, thus can further reduce costs.And due to dispersion and polarization mode dispersion larger for the radio-frequency power impact of high frequency treatment, radio-frequency power impact for low frequency place is very little, so this scheme has stronger resistant function for the impact of dispersion and polarization mode dispersion in CO-OFDM system, and the certainty of measurement of traditional polarization return-to-zero method is very large by the impact of polarization mode dispersion.

Further, can perfection be nested in wdm system in CO-OFDM system, the program be exactly the balanced detector 13 that can use low speed equally for the benefit of CO-OFDM system, greatly reduces cost like this.

Second aspect, based on same inventive concept, the embodiment of the present invention introduces a kind of Optical Signal To Noise Ratio computing system, please continue to refer to Fig. 1, comprising:

Polarization Controller 10, the input access flashlight of Polarization Controller 10, Polarization Controller 10 is for changing the polarization state of flashlight;

Intrinsic laser device 11, intrinsic laser device 11 is for generation of intrinsic light;

Coupler 12, the first input end of coupler 12 is connected to the output of Polarization Controller 10, and the second input of coupler 12 is connected to the output of intrinsic laser device 11, and coupler 12 is for carrying out mixing to flashlight and intrinsic light;

Balanced detector 13, is connected to coupler 12, and balanced detector 13 for the light signal of input balanced detector 13 is converted to the signal of telecommunication, and removes the direct current signal in the signal of telecommunication;

Electrodymamometer 14, be connected to balanced detector 13, for detecting acquisition first performance number and the second performance number, wherein, first performance number for flashlight identical with intrinsic polarisation of light state time electrodymamometer 14 performance number that detects, second performance number be flashlight vertical with intrinsic polarisation of light state time, the performance number that electrodymamometer 14 detects;

Optical Signal To Noise Ratio calculator 15, is connected to electrodymamometer 14, for obtaining the first performance number and the second performance number from electrodymamometer 14, and calculates by the first performance number and the second performance number the Optical Signal To Noise Ratio obtained in channel to be measured.

Optionally, Optical Signal To Noise Ratio calculator 15 is specifically for obtaining Optical Signal To Noise Ratio by following formulae discovery:

$\mathrm{OSNR}=10\lg \frac{P_s}{P_n}\&CenterDot;\frac{B_r}{B_n}=10\lg {\left(\frac{<I_{\max }\left(t\right)>-<I_{\min }\left(t\right)>}{2<I_{\min }\left(t\right)>}\right)}^2+10\lg \frac{B_r}{B_n}\&CenterDot;\&CenterDot;\&CenterDot;\left[3\right]$

Wherein, OSNR represents Optical Signal To Noise Ratio;

Ps representation signal power;

P _nrepresent noise power;

B _rrepresent the effective bandwidth of channel to be measured;

B _nnoise equivalent bandwidth;

<I _maxt () > represents the first performance number;

<I _mint () > represents the second performance number.

Optionally, electrodymamometer 14 specifically for:

When flashlight is identical with intrinsic polarisation of light state, detect acquisition first performance number;

When flashlight is vertical with intrinsic polarisation of light state, detect acquisition second performance number.

Optionally, electrodymamometer 14 specifically for:

By N adjustment of the polarization state of Polarization Controller 10, detect and obtain N number of performance number, N be more than or equal to 2 positive integer;

Determine that the highest performance number is the first performance number from N number of performance number;

Determine that minimum performance number is the second performance number from N number of performance number.

Optionally, please continue to refer to Fig. 1, system also comprises:

Regulate filter 16, for selecting channel to be measured from multiple channel, flashlight is by the flashlight of transmission to be measured.

Further understand to enable those skilled in the art that the embodiment of the present invention introduces based on OSNR Monitoring Method in the band of relevant mixing, by based on concrete should being used for, it is introduced below.

Embodiment one

In the present embodiment, will be introduced for CO-OFDM system for this Optical Signal To Noise Ratio computing system, and please refer to Fig. 5, this CO-OFDM system comprises following structure:

Outside cavity gas laser 50, for generation of light signal;

I/Q modulator 51, is connected to outside cavity gas laser 50, for the signal of telecommunication is modulated to area of light;

ASE (amplified spontaneous emission: magnification method) noise source 52, for generation of ASE noise;

Attenuator 53, is connected to ASE noise source 52, for regulating the size of ASE noise;

50:50 coupler 54, is connected to I/Q modulator 51 and attenuator 53;

10:90 coupler 55, is connected to 50:50 coupler 54, and wherein 50:50 coupler 54 and 10:90 coupler 55 are for being coupled ASE noise with light signal, thus can change OSNR;

Tunable bandpass filters 56, is connected to 10:90 coupler 55, for selecting the wavelength that will monitor in multi-wavelength system (such as: wdm system), if system is Single wavelength system, does not then need tunable bandpass filters 56;

Spectrometer 57, for measuring the standard value of OSNR;

Polarization Controller 58, is connected to tunable bandpass filters 56, for controlling the polarization state of light signal;

Intrinsic laser device 59, for generation of intrinsic light;

The 50:50 coupler 60 of 2X2, is connected to Polarization Controller 58 and intrinsic laser device 59, for intrinsic light and light signal are carried out mixing;

Balanced detector 61, is connected to the 50:50 coupler 60 of 2X2, for the light signal of input balanced detector is converted to the signal of telecommunication, and removes the direct current signal in the signal of telecommunication;

Electrodymamometer 62, with for detecting acquisition first performance number and the second performance number, wherein, first performance number for flashlight identical with intrinsic polarisation of light state time the electrodymamometer performance number that detects, second performance number be flashlight vertical with intrinsic polarisation of light state time, the performance number that electrodymamometer detects.

Embodiment two

In the present embodiment, result of calculation for CO-OFDM system will be introduced, system transfers be the 16QAM signal of 40Gb/s, the OSNR monitoring result obtained as shown in Figure 6, wherein the longitudinal axis of Fig. 6 represents the calculated value of the OSNR determined by formula [3], the transverse axis of Fig. 6 represents the standard value of the OSNR measured by spectrometer 57, and the calculated value of OSNR and standard value are more or less the same as can be seen from Figure 6, and accuracy is higher as can be seen here.

In addition, please refer to Fig. 7, the calculated value of the OSNR that the ordinate of Fig. 7 represents is relative to the error of standard value, and abscissa represents the standard value of OSNR, and when OSNR changes in the scope of 10-25dB as seen from Figure 7, the error of calculated value is within 0.5dB.

The one or more embodiment of the present invention, at least has following beneficial effect:

Due in embodiments of the present invention, provide that a kind of method is applied in Optical Signal To Noise Ratio computing system, and system comprises: Polarization Controller based on OSNR Monitoring Method in the band of relevant mixing, the input access flashlight of Polarization Controller; Intrinsic laser device; Coupler, the first input end of coupler is connected to the output of Polarization Controller, and the second input of coupler is connected to the output of intrinsic laser device; Balanced detector, is connected to coupler; Electrodymamometer, is connected to balanced detector; Optical Signal To Noise Ratio calculator, is connected to electrodymamometer; Method comprises: the wavelength controlling the flashlight of channel to be measured is identical with the wavelength of the intrinsic light that intrinsic laser device produces; Acquisition first performance number and the second performance number is detected by electrodymamometer, and the first performance number and the second performance number are sent to Optical Signal To Noise Ratio calculator, wherein, first performance number for flashlight identical with intrinsic polarisation of light state time the electrodymamometer performance number that detects, second performance number be flashlight vertical with intrinsic polarisation of light state time, the performance number that electrodymamometer detects; Optical Signal To Noise Ratio calculator calculates by the first performance number and the second performance number the Optical Signal To Noise Ratio obtained in channel to be measured.Also namely in such scheme, by changing the polarization state of flashlight, when with intrinsic photomixing, utilize the polarization characteristic that signal is different with noise, export response by the difference of balanced detector after mixing and measure OSNR, what the program was directly measured is the noise being with interior central wavelength, so can not exist by error existing during out-of-band noise matching in-band noise, and then can improve the accuracy of OSNR in detection zone; And the impact of optical filter can not be subject to, and then further improve accuracy;

And compared to traditional palarization multiplexing return-to-zero method, the method can perfectly combine with present coherent detection system, and does not need extra polarization beam apparatus, and then has the technique effect reduced costs.

Although describe the preferred embodiments of the present invention, those skilled in the art once obtain the basic creative concept of cicada, then can make other change and amendment to these embodiments.So claims are intended to be interpreted as comprising preferred embodiment and falling into all changes and the amendment of the scope of the invention.

Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these change and modification.

Claims (10)

1. based on an OSNR Monitoring Method in the band of relevant mixing, it is characterized in that, described method is applied in Optical Signal To Noise Ratio computing system, and described system comprises: Polarization Controller, the input access flashlight of described Polarization Controller; Intrinsic laser device; Coupler, the first input end of described coupler is connected to the output of described Polarization Controller, and the second input of described coupler is connected to the output of described intrinsic laser device; Balanced detector, is connected to described coupler; Electrodymamometer, is connected to described balanced detector; Optical Signal To Noise Ratio calculator, is connected to described electrodymamometer; Described method comprises:

The wavelength controlling the flashlight of channel to be measured is identical with the wavelength of the intrinsic light that described intrinsic laser device produces;

Acquisition first performance number and the second performance number is detected by described electrodymamometer, and described first performance number and described second performance number are sent to described Optical Signal To Noise Ratio calculator, wherein, described first performance number for described flashlight identical with described intrinsic polarisation of light state time the described electrodymamometer performance number that detects, described second performance number be described flashlight vertical with described intrinsic polarisation of light state time, the performance number that described electrodymamometer detects;

Described Optical Signal To Noise Ratio calculator calculates by described first performance number and described second performance number the Optical Signal To Noise Ratio obtained in described channel to be measured.

2. the method for claim 1, is characterized in that, described Optical Signal To Noise Ratio calculator obtains described Optical Signal To Noise Ratio by following formulae discovery:

$\mathrm{OSNR}=10\lg \frac{P_s}{P_n}\&CenterDot;\frac{B_r}{B_n}=10\lg {\left(\frac{<I_{\max }\left(t\right)>-<I_{\min }\left(t\right)>}{2<I_{\min }\left(t\right)>}\right)}^2+10\lg \frac{B_r}{B_n}$

Wherein, OSNR represents Optical Signal To Noise Ratio;

Ps representation signal power;

P _nrepresent noise power;

B _rrepresent the effective bandwidth of described channel to be measured;

B _nnoise equivalent bandwidth;

<I _maxt () > represents the first performance number;

<I _mint () > represents the second performance number.

3. the method for claim 1, is characterized in that, described by described electrodymamometer detection acquisition first performance number and the second performance number, specifically comprises:

Control described flashlight identical with described intrinsic polarisation of light state, and detect described first performance number of acquisition by described electrodymamometer;

Control described flashlight vertical with described intrinsic polarisation of light state, and detect acquisition second performance number by described electrodymamometer.

4. the method for claim 1, is characterized in that, described by described electrodymamometer detection acquisition first performance number with by described second performance number of described electrodymamometer detection acquisition, specifically comprises:

The polarization state of N the described Polarization Controller of adjustment, and then detect the N number of performance number of acquisition by described electrodymamometer, N be more than or equal to 2 positive integer;

Determine that the highest performance number is described first performance number from described N number of performance number;

Determine that minimum performance number is described second performance number from described N number of performance number.

5. the method as described in as arbitrary in claim 1-4, it is characterized in that, before the wavelength of the flashlight of described control channel to be measured is identical with the wavelength of the intrinsic light that described intrinsic laser device produces, described method also comprises:

From multiple channel, select described channel to be measured, described flashlight is by the flashlight of described transmission to be measured.

6. an Optical Signal To Noise Ratio computing system, is characterized in that, comprising:

Polarization Controller, the input access flashlight of described Polarization Controller, described Polarization Controller is for changing the polarization state of described flashlight;

Intrinsic laser device, described intrinsic laser device is for generation of intrinsic light;

Coupler, the first input end of described coupler is connected to the output of described Polarization Controller, and the second input of described coupler is connected to the output of described intrinsic laser device, and described coupler is used for carrying out mixing to described flashlight and described intrinsic light;

Balanced detector, is connected to described coupler, and described balanced detector is used for the light signal of the described balanced detector of input to be converted to the signal of telecommunication, and removes the direct current signal in the described signal of telecommunication;

Electrodymamometer, be connected to described balanced detector, for detecting acquisition first performance number and the second performance number, wherein, described first performance number for described flashlight identical with described intrinsic polarisation of light state time the described electrodymamometer performance number that detects, described second performance number be described flashlight vertical with described intrinsic polarisation of light state time, the performance number that described electrodymamometer detects;

Optical Signal To Noise Ratio calculator, is connected to described electrodymamometer, for obtaining described first performance number and described second performance number from described electrodymamometer, and calculates by described first performance number and described second performance number the Optical Signal To Noise Ratio obtained in described channel to be measured.

7. system as claimed in claim 6, it is characterized in that, described Optical Signal To Noise Ratio calculator is specifically for obtaining described Optical Signal To Noise Ratio by following formulae discovery:

$\mathrm{OSNR}=10\lg \frac{P_s}{P_n}\&CenterDot;\frac{B_r}{B_n}=10\lg {\left(\frac{<I_{\max }\left(t\right)>-<I_{\min }\left(t\right)>}{2<I_{\min }\left(t\right)>}\right)}^2+10\lg \frac{B_r}{B_n}$

Wherein, OSNR represents Optical Signal To Noise Ratio;

Ps representation signal power;

P _nrepresent noise power;

B _rrepresent the effective bandwidth of described channel to be measured;

B _nnoise equivalent bandwidth;

<I _maxt () > represents the first performance number;

<I _mint () > represents the second performance number.

8. system as claimed in claim 7, is characterized in that, described electrodymamometer specifically for:

When described flashlight is identical with described intrinsic polarisation of light state, detects and obtain described first performance number;

When described flashlight is vertical with described intrinsic polarisation of light state, detects and obtain described second performance number.

9. system as claimed in claim 7, is characterized in that, described electrodymamometer specifically for:

By N adjustment of the polarization state of described Polarization Controller, detect and obtain N number of performance number, N be more than or equal to 2 positive integer;

Determine that the highest performance number is described first performance number from described N number of performance number;

Determine that minimum performance number is described second performance number from described N number of performance number.

10. the system as described in as arbitrary in claim 6-9, it is characterized in that, described system also comprises:

Regulate filter, for selecting described channel to be measured from multiple channel, described flashlight is by the flashlight of described transmission to be measured.