CN101369845B - Chromatic dispersion monitoring method, system and apparatus - Google Patents

Abstract

The invention discloses a chromatic dispersion monitoring method. A probe tone with two or more than two different frequencies is used to modulate a light carrier at a transmission terminal, an upper and a lower sideband monitor signals corresponding to each probe tone are extracted from the light carrier at a receiving terminal, a monitor current corresponding to each probe tone is obtained after frequency mixing and filtering of the upper and lower sideband monitor signals for each group, then a chromatic dispersion accumulative value is calculated according to each monitor current and the functional relation between the monitor current and the chromatic dispersion accumulation. The invention also discloses a chromatic dispersion monitoring system, a modulation device and a monitoring device. Through the invention, the chromatic dispersion monitor range is improved while ensuring the chromatic dispersion monitoring result resolution.

Description

A kind of chromatic dispersion monitoring method, system and device

Technical field

The present invention relates to optical communication field, relate to a kind of chromatic dispersion monitoring method, system and device particularly.

Background technology

Along with the development of optical communication technique, fibre loss no longer is the principal element of limit fibre transmission range, and chromatic dispersion has caused people's attention gradually.CHROMATIC DISPERSION IN FIBER OPTICS can represent with diverse ways, and commonly used have maximum delay difference Δ τ and a dispersion parameters D.The maximum delay difference is described time delay poor of fast and the slowest light wave composition of optical fiber medium velocity, after the light wave transmissions unit distance of the dispersion parameters unit of representative wavelength interval the delay of the time of advent poor, these two kinds of expressions commonly used all belong to the time-domain representation method.The chromatic dispersion meeting causes digital light pulse signal broadening in transmission, causes intersymbol to be disturbed mutually, and error rate of system is increased, thereby has limited the further growth of message capacity and communication distance.For improving communication quality, need compensate chromatic dispersion.Fig. 1 shows the sketch map of compensating adaptive dispersion scheme in the prior art, can be known by Fig. 1, and online real-time chromatic dispersion monitoring is very important to the realization of compensating adaptive dispersion.

Fig. 2 shows the method sketch map that uses single-frequency monitoring phone to carry out double-side band phase shift monitoring chromatic dispersion in the prior art.As shown in Figure 2, at transmitter terminal, the RF generator produces a single frequency sinusoidal ripple monitoring phone, and it carries out intensity modulated to the light carrier that carries digital signal.The monitoring phone that will occur the lower sideband symmetry in the modulation spectrum later, because the existence of optical fiber dispersion, two sidebands of monitoring phone will transmit with different speed.Optical fiber at receiving terminal, uses optical coupler to isolate two paths of signals through after the Optical Fiber Transmission of certain distance, uses two optical filters to extract the last lower sideband of light carrier respectively.Through just extracting the sinusoidal signal of lower sideband after opto-electronic conversion and the bandpass filtering treatment.Because this two-way monitor signal extracts from different frequency bands respectively, must have delay inequality between them.The sinusoidal monitor signal input of this two-way phase discriminator, to try to achieve relative time delay poor through monitoring phase shift difference between them, thereby calculates the broadening of digit pulse through the generation of this section Optical Fiber Transmission.

In such scheme, because the phase shift difference of output is a periodic function, so monitoring range and resolution all has restriction, and the frequency that improves the monitoring phone can improve monitoring resolution, still can reduce the monitoring range of system.

Summary of the invention

The embodiment of the invention provides a kind of chromatic dispersion monitoring method, system and device, can under the situation that guarantees resolution, improve the scope that chromatic dispersion detects.

In order to solve the problems of the technologies described above, the embodiment of the invention has proposed a kind of chromatic dispersion monitoring method, comprising:

At transmitting terminal, use two or more monitoring phones of different frequency that light carrier is modulated, and the light carrier after will modulating send through optical fiber;

At receiving terminal; Receive the light carrier after the said modulation; Therefrom extract the upper and lower sideband monitor signal of respectively monitoring phone modulation generation respectively by said; And respectively the upper and lower sideband monitor signal that is produced by each monitoring phone modulation that extracts is carried out mixing, obtain monitoring current corresponding to each monitoring phone;

Confirm the chromatic dispersion aggregate-value that monitors according to said each monitoring current.

Correspondingly, the embodiment of the invention provides a kind of chromatic dispersion monitoring system, comprising:

Modulating device is used for using two or more monitoring phones of different frequency that light carrier is modulated at transmitting terminal;

Monitoring device; Be used for extracting the upper and lower sideband monitor signal of respectively monitoring phone modulation generation from said light carrier by said at receiving terminal; And respectively each monitoring phone is modulated the upper and lower sideband monitor signal that produces and carry out mixing, obtain monitoring current corresponding to each monitoring phone;

Processing unit is used for confirming the chromatic dispersion aggregate-value that monitors according to said each monitoring current.

The embodiment of the invention also provides a kind of modulating device; Include modulating unit; Be used for using the monitoring phone that light carrier is modulated at transmitting terminal; Also include control unit, be used to control said modulating unit and use two or more monitoring phones of different frequency that light carrier is modulated successively according to time sequencing.

The embodiment of the invention also provides another kind of modulating device; Be used for using the monitoring phone that light carrier is modulated at transmitting terminal; It is characterized in that; Said modulating device includes two or more modulating units, and wherein, each modulating unit uses the monitoring phone corresponding with it that light carrier is modulated.

The embodiment of the invention provides a kind of monitoring device; Include monitoring means; Be used for extracting the upper and lower sideband monitor signal that produces by said monitoring phone modulation at the light carrier that receiving terminal is modulated from monitored phone; And said upper and lower sideband monitor signal is carried out mixing obtain monitoring current, also include control unit, be used to control said monitoring means and successively filtering bandwidth switched to and the corresponding bandwidth of each monitoring phone according to time sequencing; Said time sequencing is with consistent to the time sequencing that said light carrier is modulated successively at the said phone of respectively monitoring of transmitting terminal, saidly respectively monitors the monitoring phone that phone is two or more different frequencies.

The embodiment of the invention also provides another kind of monitoring device; Be used for extracting the upper and lower sideband monitor signal that produces by said monitoring phone modulation at the light carrier that receiving terminal is modulated from monitored phone; And said upper and lower sideband monitor signal is carried out mixing obtain monitoring current; Said monitoring device includes two or more monitoring means; Wherein, each monitoring means is used for extracting the upper and lower sideband that is produced by the monitoring phone corresponding with it modulation and said upper and lower sideband monitor signal being carried out mixing from light carrier at receiving terminal obtaining corresponding monitoring current.

Embodiment of the present invention embodiment has following beneficial effect:

The chromatic dispersion monitoring method that the embodiment of the invention provides, system and device; Two or more monitoring phones through using different frequency are modulated light carrier; Respectively the upper and lower sideband monitor signal that is produced by each monitoring phone modulation is carried out mixing at receiving terminal and obtain monitoring current, and then the functional relation between being added up with chromatic dispersion by each monitoring current and each monitoring current is confirmed the chromatic dispersion aggregate-value that monitors corresponding to each monitoring phone.Monitoring current i becomes the cosine function relation with chromatic dispersion accumulative total DL, promptly

$i=A\cos \left(\frac{{\mathrm{\λ}}^2{\mathrm{\ω}}^2}{2\mathrm{c\π}}\mathrm{DL}\right)$

Wherein, A is the coefficient relevant with input power, and λ is an optical carrier wavelength, and ω is the angular frequency of monitoring phone.The monitoring range of chromatic dispersion accumulative total DL is determined by following formula:

$0\≤\frac{D{\mathrm{\λ}}^2{\mathrm{\ω}}^{2}L}{2\mathrm{c\π}}\≤\mathrm{\π}$

Hence one can see that, and the monitoring range of the DL of low more its decision of frequency of monitoring phone is just big more; In addition, can know that through the cosine function relation of monitoring current i and chromatic dispersion accumulative total DL the monitoring resolution of the DL of low more its decision of frequency of monitoring phone is just low more.

In embodiments of the present invention, adopt the monitoring phone of two or more different frequencies that light carrier is modulated, establish its angular frequency and be respectively ω ₁, ω ₂..., ω _n, then, monitoring current that obtains and the functional relation of DL are respectively:

$i_1=A\cos \left(\frac{{\mathrm{\λ}}^2{{\mathrm{\ω}}_1}^2}{2\mathrm{c\π}}\mathrm{DL}\right),i_2=A\cos \left(\frac{{\mathrm{\λ}}^2{{\mathrm{\ω}}_2}^2}{2\mathrm{c\π}}\mathrm{DL}\right),\·\·\·\·\·\·,i_n=A\cos \left(\frac{{\mathrm{\λ}}^2{{\mathrm{\ω}}_n}^2}{2\mathrm{c\π}}\mathrm{DL}\right)$

Then, can know, be ω by frequency ₁The monitoring range of DL of monitoring phone decision do

By frequency is ω ₂The monitoring range of DL of monitoring phone decision do ..., be ω by frequency _nThe monitoring range of DL of monitoring phone decision do If

Least common multiple be N, then, be ω by frequency ₁, ω ₂..., ω _nThe monitoring range of the DL that respectively monitors the common decision of phone be [0, N], in the resolution that the resolution of the DL that is monitored determines for each monitoring phone higher one.So,, under the situation that has guaranteed resolution, improved the monitoring range of chromatic dispersion accumulative total through the embodiment of the invention.

Description of drawings

Fig. 1 is the principle schematic of compensating adaptive dispersion scheme in the prior art;

Fig. 2 is the principle schematic of chromatic dispersion monitoring method in the prior art;

Fig. 3 is the schematic flow sheet of the embodiment one of chromatic dispersion monitoring method among the present invention;

Fig. 4 is the schematic flow sheet of step S3005 one embodiment among Fig. 3;

Fig. 5 is the sketch map of the application implementation example of chromatic dispersion monitoring method among the present invention;

Fig. 6 is the sketch map of the Another Application embodiment of chromatic dispersion monitoring method among the present invention;

Fig. 7 is that the functional module of chromatic dispersion monitoring system embodiment two among the present invention is formed sketch map;

Fig. 8 is that the functional module of chromatic dispersion monitoring system embodiment three among the present invention is formed sketch map;

Fig. 9 is that the functional module of chromatic dispersion monitoring system embodiment four among the present invention is formed sketch map;

Figure 10 is that the functional module of chromatic dispersion monitoring system embodiment five among the present invention is formed sketch map;

Figure 11 is that the functional module of chromatic dispersion monitoring system embodiment six among the present invention is formed sketch map.

Embodiment

Below in conjunction with accompanying drawing the present invention is done further in detail clearly explanation.

Chromatic dispersion monitoring method that the embodiment of the invention provides and system modulate light carrier through the two or more monitoring phones that use different frequency; Thereby obtain corresponding monitoring current of respectively monitoring phone at receiving terminal, confirm the chromatic dispersion aggregate-value that monitors jointly according to said each monitoring current then.

Fig. 3 shows the schematic flow sheet of chromatic dispersion monitoring method one embodiment among the present invention, in the present embodiment, chromatic dispersion monitoring method of the present invention is described further as example with the situation of the monitoring phone that uses two different frequencies, comprising:

Step S3001:, use the first monitoring phone of a certain frequency that light carrier is modulated at transmitting terminal.

If the angular frequency of the first monitoring phone is ω ₁Angular frequency is ω ₀Light carrier through angular frequency be ω ₁Cosine monitoring phone intensity modulated after, the electric field expression formula is:

${\mathrm{<figure-callout\; id="0"\; label="E"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">E</figure-callout>}}_0=\sqrt{I_0[1+m\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1)]}\cos ({\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0)$

Through after the intensity modulated, modulation signal comprises many side frequency (ω ₀± i ω ₁), the first sideband ω ₀± ω ₁Signal is the strongest.After ignoring the high-order side frequency, this electric field can be regarded as by the light carrier and first sideband (comprising upper sideband and lower sideband) of monitoring phone and form.Its upper and lower sideband signals is expressed as:

E _U1＝A _U1cos[(ω ₀+ω ₁)t+φ ₀+φ ₁]

E _L1＝A _L1cos[(ω ₀-ω ₁)t+φ ₀-φ ₁]

Step S3002:, use the second monitoring phone of another frequency that said light carrier is modulated at said transmitting terminal.

If the angular frequency of the second monitoring phone is ω ₂Equally, the upper and lower sideband signals that is produced by the second monitoring phone modulation is expressed as:

E _U2＝A _U2cos[(ω ₀+ω ₁)t+φ ₀+φ ₁]

E _L2＝A _L2cos[(ω ₀-ω ₁)t+φ ₀-φ ₁]

Light carrier after the modulation of monitoring phone transmits in optical fiber, arrives receiving terminal through after the distance L.If fissipation factor is α, through after the distance L, the optical electric field of light carrier is expressed as

E ₀＝A ₀e ^-αLcos(ω ₀t+φ ₀-β ₀L)

Step S3003: at receiving terminal, from the light carrier after the said modulation, extract the upper and lower sideband monitor signal that produces by the said first monitoring phone modulation, and said upper and lower sideband monitor signal is obtained first monitoring current after mixing, filtering.

Through after the distance L, can extract the upper and lower sideband monitor signal that produces by the said first monitoring phone modulation at receiving terminal, through opto-electronic conversion and filtering, the signal that extracts is a current signal:

$i_{U1}\left(t\right)=2\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; U"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_U\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

$i_{L1}\left(t\right)=2\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

Wherein, R is the sensitivity of light-detecting device, and K is for being the proportionality coefficient relevant with the optical filter amplitude-frequency characteristic.

Above-mentioned two signals are promptly obtained a monitoring current after mixing, filtering:

${\mathrm{<figure-callout\; id="1"\; label="i"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">i</figure-callout>}}_1=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U1}{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos \left({\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L\right)=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U1}{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Can know by following formula, determine by following formula by the monitoring range of the chromatic dispersion accumulative total DL of the first monitoring phone decision:

$0\&le;\frac{D{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^{2}L}{2\mathrm{C\&pi;}}\&le;\mathrm{\&pi;},$ Promptly $0\&le;\mathrm{DL}\&le;\frac{2c{\mathrm{\&pi;}}^2}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}$

Promptly when the chromatic dispersion aggregate-value is in this scope, use angular frequency to be ω ₁The monitoring phone chromatic dispersion aggregate-value of trying to achieve be only accurately.When the chromatic dispersion aggregate-value exceeds this scope,, just can't confirm according to the chromatic dispersion aggregate-value that monitoring current calculated because monitoring current becomes the cosine function relation with DL.

Step S3004: at said receiving terminal, from said light carrier, extract the upper and lower sideband monitor signal that produces by the said second monitoring phone modulation, and said upper and lower sideband monitor signal is obtained second monitoring current after mixing, filtering.

Through after the distance L, can extract the upper and lower sideband monitor signal that produces by the said second monitoring phone modulation at receiving terminal, through opto-electronic conversion and filtering, the signal that extracts is a current signal:

$i_{U2}\left(t\right)=2\mathrm{RK}{A}_0{A}_{U2}\cos ({\mathrm{\&omega;}}_{2}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{2}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_2^{2}L)$

$i_{L2}\left(t\right)=2\mathrm{RK}{A}_0{A}_{L2}\cos ({\mathrm{\&omega;}}_{2}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{2}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_2^{2}L)$

Wherein, R is the sensitivity of light-detecting device, and K is for being the proportionality coefficient relevant with the optical filter amplitude-frequency characteristic.

Above-mentioned two signals are promptly obtained another monitoring current after mixing, filtering:

$i_2=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U2}{A}_{L2}\cos \left({\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_2^{2}L\right)=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U2}{A}_{L2}\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Can know by following formula, determine by following formula by the monitoring range of the chromatic dispersion accumulative total DL of the second monitoring phone decision:

$0\&le;\frac{D{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^{2}L}{2\mathrm{C\&pi;}}\&le;\mathrm{\&pi;}$ , promptly $0\&le;\mathrm{DL}\&le;\frac{2c{\mathrm{\&pi;}}^2}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}$

Promptly when the chromatic dispersion aggregate-value is in this scope, use angular frequency to be ω ₂The monitoring phone chromatic dispersion aggregate-value of trying to achieve be only accurately.When the chromatic dispersion aggregate-value exceeds this scope,, just can't confirm according to the chromatic dispersion aggregate-value that monitoring current calculated because monitoring current becomes the cosine function relation with DL.

To sum up, angular frequency is that corresponding monitoring current i of the monitoring phone of ω and the functional relation of DL are:

$i=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_U{A}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Step S3005: confirm the chromatic dispersion aggregate-value that monitors according to said first monitoring current and second monitoring current.

Because the chromatic dispersion monitoring point of receiving terminal is identical, and the light carrier modulate of two monitoring phones passes through the optical fiber arrival receiving terminal of same segment distance, so, the first monitoring current i ₁The pairing DL and the second monitoring current i ₂Pairing DL value is identical.According to the first monitoring current i ₁Value, the second monitoring current i ₂Value, and the functional relation between monitoring current and DL, we can determine the DL value that monitors.The monitoring range that adds up DL owing to the chromatic dispersion by the first monitoring phone decision does $0\&le;\mathrm{DL}\&le;\frac{2c{\mathrm{\&pi;}}^2}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2},$ Monitoring range by the chromatic dispersion accumulative total DL of the second monitoring phone decision does $0\&le;\mathrm{DL}\&le;\frac{2c{\mathrm{\&pi;}}^2}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2},$ If With Least common multiple be M, then, can know that the monitoring range by the chromatic dispersion accumulative total DL of the first monitoring phone and the common decision of the second monitoring factor is [0, M].Monitoring range when this monitoring range is obviously monitored phone greater than the independent use first monitoring phone or second.And the resolution of the DL that is monitored is one higher in the resolution of two monitoring phones decisions.

Through the foregoing description, can under the situation that guarantees resolution, improve the scope of chromatic dispersion monitoring.

As a kind of execution mode, the step that from said light carrier, extracts the upper and lower sideband monitor signal that is produced by the modulation of monitoring phone among step S3003 and the step S3004 specifically can comprise:

Step S4001: said light carrier is divided into two bundle signals.

For example, can use optical coupler that the light carrier of monitored phone modulation is divided into two bundles at receiving terminal.

Step S4002: said two-beam carrier wave is carried out light filtering respectively obtain monitoring light signal by the upper and lower sideband that the said first monitoring phone or the second monitoring phone modulation produce.

Select filtering bandwidth respectively, obtain upper and lower sideband monitoring light signal after the light filtering corresponding to upper and lower sideband monitor signal.

Step S4003: said upper and lower sideband monitoring light signal is carried out opto-electronic conversion respectively.

For example, realize the opto-electronic conversion of said upper and lower sideband monitor signal through photodetector.

Step S4004: the said upper and lower sideband monitor signal that will pass through after the opto-electronic conversion carries out the electrofiltration ripple respectively, the upper and lower sideband monitoring signal of telecommunication that obtains extracting.

If fissipation factor is α, through after the distance L, the optical electric field that light carrier reaches the upper and lower sideband monitor signal that is produced by the first monitoring phone modulation is expressed as:

E ₀＝A ₀e ^-αLcos(ω ₀t+φ ₀-β ₀L)

E _U1＝A _U1e ^-αLcos[(ω ₀+ω ₁)t+φ ₀+φ ₁-β _UL]

E _L1＝A _L1e ^-αLcos[(ω ₀-ω ₁)t+φ ₀-φ ₁-β _LL]

Under the situation of not considering high-order dispersion, with propagation constant β at ω ₀Near be launched into Taylor series,

$\mathrm{\&beta;}\left(\mathrm{\&omega;}\right)={\mathrm{\&beta;}}_0+{\mathrm{\&beta;}}_1\left(\mathrm{\&Delta;\&omega;}\right)+\frac{1}{2}{\mathrm{\&beta;}}_2{\left(\mathrm{\&Delta;\&omega;}\right)}^2$

In the monitoring side, leach upper sideband E fully with filter _U1The time can leach part E ₀, use

Expression,

${\mathrm{<figure-callout\; id="0"\; label="E"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">E</figure-callout>}}_0^{\&prime;}=K{A}_0{e}^{-\mathrm{\&alpha;L}}\cos ({\mathrm{\&omega;}}_{0}t+{\mathrm{\&phi;}}_0-{\mathrm{\&beta;}}_{0}L-{\mathrm{\&phi;}}_F)$

In the formula, K is the proportionality coefficient relevant with the optical filter amplitude-frequency characteristic, φ _FBe the phase shift parameters relevant with the optical filter phase-frequency characteristic.Therefore, the luminous power that is projected to photodetector does

$P\left(t\right)={|E_U+\mathrm{<figure-callout\; id="0"\; label="K\; E"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">K</figure-callout>}{E}_{}{}_0|}^2=K^2{A}_0^2+A_{\mathrm{<figure-callout\; id="1"\; label="U"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">U</figure-callout>}1}^2+2K{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; U"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_U\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

This luminous power is the photodetector of R through sensitivity, obtains photoelectric current I=RP, pass through band pass filter again after, just can obtain the upper sideband monitor signal

$i_{U1}\left(t\right)=2\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; U"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_U\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

Because last lower sideband optical filter has identical amplitude-frequency and phase-frequency characteristic, in like manner can get the lower sideband monitor signal

$i_{L1}\left(t\right)=2\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

In like manner, can from light carrier, extract by angular frequency is ω ₂The upper and lower sideband signals that produces of the second monitoring phone modulation:

$i_{U2}\left(t\right)=2\mathrm{RK}{A}_0{A}_{U2}\cos ({\mathrm{\&omega;}}_{2}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{2}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_2^{2}L)$

$i_{L2}\left(t\right)=2\mathrm{RK}{A}_0{A}_{L2}\cos ({\mathrm{\&omega;}}_{2}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{2}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_2^{2}L)$

What to sum up, from light carrier, extract is that the upper and lower sideband monitor signal of the monitoring phone of ω can be expressed as corresponding to angular frequency:

$i_U\left(t\right)=2\mathrm{RK}{A}_0{A}_U\cos (\mathrm{\&omega;}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1\mathrm{\&omega;}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}^{2}L)$

$i_L\left(t\right)=2\mathrm{RK}{A}_0{A}_L\cos (\mathrm{\&omega;}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1\mathrm{\&omega;}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}^{2}L)$

In the above-described embodiments, step S3001 and step S3002 can carry out simultaneously, promptly; At receiving terminal; Use two monitoring phones of different frequency that light carrier is modulated simultaneously, the light carrier that will modulate two monitoring phones of different frequency then is coupled in the same optical fiber and transmits, through after the distance L; Extract the upper and lower sideband monitor signal that produces by the modulation of two monitoring phones respectively at receiving terminal; And carry out mixing respectively, and obtain two monitoring currents, confirm the DL value that monitors according to the functional relation between two monitoring current values and monitoring current and DL.In this execution mode, need the devices such as signal extraction, mixing of two cover modulation and receiving terminal, so that two monitoring phones are carried out action respectively, so hardware cost is higher.

As another kind of execution mode, step S3001 and step S3002 also can carry out according to time sequencing successively, that is, at a time with a monitoring phone light carrier is modulated earlier, obtain the monitoring current corresponding to this monitoring phone at receiving terminal; At another constantly, switch to another monitoring phone, use another monitoring phone that light carrier is modulated, obtain a monitoring current corresponding to this monitoring phone at receiving terminal.Because the chromatic dispersion monitoring point of receiving terminal is identical, and the light carrier modulate of two monitoring phones is through the optical fiber arrival receiving terminal of same segment distance, so two pairing DL values of monitoring current are identical, the difference with the moment does not change.Can confirm the DL value that monitors equally according to the functional relation between two monitoring current values and monitoring current and DL.It should be noted that when switching the monitoring phone, switch the filtering bandwidth of receiving terminal simultaneously, make its bandwidth corresponding with the monitoring phone.Compare with a last embodiment, in the present embodiment two monitoring phones can the common modulation device and signal extracting device, the mixing and filtering device of receiving terminal, has saved cost, but the last embodiment trouble of its control mode.

Fig. 4 shows the schematic flow sheet of the embodiment of step S3005 among Fig. 3, comprising:

Step S5001: the functional relation according between said first monitoring current and monitoring current and the chromatic dispersion accumulative total draws one group of chromatic dispersion aggregate-value with first specific period relation.

As previously mentioned, angular frequency is that corresponding monitoring current i of the monitoring phone of ω and the functional relation of DL are:

$i=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_U{A}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Angular frequency is ω ₁The first corresponding monitoring current i of the first monitoring phone ₁And the functional relation between the chromatic dispersion accumulative total DL is:

$i_1=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U1}{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Wherein, R, K, A ₀, A _U1, A _L1For known, when we have known i ₁During value, just can ask corresponding DL value according to this relational expression.Because cosine function is a periodic function, so the DL value that we obtain is a plurality of values with period-luminosity relation, this cycle is relevant with the frequency of the first monitoring phone.If detected i ₁Value is i ₁₀, then the value of DL is:

$\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}(2\mathrm{N\&pi;}\&PlusMinus;\mathrm{<figure-callout\; id="10"\; label="Arccos\; i"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">Arccos</figure-callout>}\frac{i_{}}{}\frac{{}_{10}}{2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U1}{A}_{L1}}),$ Wherein, n is an integer, n=0,1,2,3......

Step S5002: the functional relation according between said second monitoring current and monitoring current and the chromatic dispersion accumulative total draws one group of chromatic dispersion aggregate-value with second specific period relation.

In like manner, establishing corresponding to angular frequency is ω ₂Second the monitoring phone the second monitoring current i ₂Value be i ₂₀, then the value of DL is:

$\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}(2\mathrm{M\&pi;}\&PlusMinus;\mathrm{<figure-callout\; id="20"\; label="Arccos\; i"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">Arccos</figure-callout>}\frac{i_{}}{}\frac{{}_{20}}{2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U2}{A}_{L2}}),$ Wherein, m is an integer, m=0,1,2,3......

Step S5003: according to the said two groups chromatic dispersion aggregate-values that have the chromatic dispersion aggregate-value of specific period relation and confirm by the chromatic dispersion monitoring range of said two monitoring phones decision to monitor.

As previously mentioned, first monitoring current is identical with the corresponding DL value of second monitoring current, so, can from top two groups of DL values, confirm the DL value that equates.The DL value that should equate still has a plurality of, but, as previously mentioned; The chromatic dispersion monitoring range of being confirmed by two monitoring phones is [0, M], in this monitoring range; The DL value that equates has only unique one, and therefore, we can confirm the DL value of the DL value that equates for monitoring in this chromatic dispersion monitoring range.

The expression formula of the monitor signal of the upper and lower sideband that is produced by the first monitoring phone modulation that extracts at receiving terminal as previously mentioned, is:

$i_{U1}\left(t\right)=2\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; U"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_U\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

$i_{L1}\left(t\right)=2\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos ({\mathrm{\&omega;}}_{1}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1{\mathrm{\&omega;}}_{1}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}_1^{2}L)$

If i _U1(t), i _L1(t) current effective value is respectively I _U1, I _L1, then can know, $I_{U1}=\sqrt{2}\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; U"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_U,$ ${\mathrm{<figure-callout\; id="1"\; label="I\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">I</figure-callout>}}_L=\sqrt{2}\mathrm{RK}{A}_0{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L,$ First monitoring current that then above-mentioned two signals obtain after mixing, filtering is:

$i_1=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U1}{\mathrm{<figure-callout\; id="1"\; label="A\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">A</figure-callout>}}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)=I_{U1}{\mathrm{<figure-callout\; id="1"\; label="I\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">I</figure-callout>}}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

In like manner, establish i _U2(t), i _L2(t) current effective value is respectively I _U2, I _L2, second monitoring current that then obtains is:

$i_2=I_{U2}{I}_{L2}\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

So, as long as after extracting the upper and lower sideband monitor signal that produces by the modulation of monitoring phone, obtain their current effective value, just can obtain normalized monitoring current through calculating:

The first normalization monitoring current: $i_{01}=\frac{i_1}{I_{U1}{\mathrm{<figure-callout\; id="1"\; label="I\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">I</figure-callout>}}_L}=\mathrm{Cos}\left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}{2\mathrm{C\&pi;}}\mathrm{DL}\right)$

The second normalization monitoring current: $i_{02}=\frac{i_2}{I_{U2}{I}_{L2}}=\mathrm{Cos}\left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}{2\mathrm{C\&pi;}}\mathrm{DL}\right)$

To sum up, angular frequency is the corresponding normalization monitoring current i of monitoring phone of ω ₀With the functional relation of DL be:

$i_0=\frac{i}{I_U{I}_L}=\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

As a kind of execution mode, can obtain its current effective value through the upper and lower sideband monitor signal that uses the monitoring of current monitoring table to extract.

Therefore, as another kind of execution mode, the step S3005 among Fig. 3 can realize according to the following step:

Step S6001: the effective current value that reaches the upper and lower sideband monitor signal that is produced by the said first monitoring phone modulation according to said first monitoring current obtains the first normalization monitoring current.

That is, by i ₁, I _U1, I _L1Calculate $i_{01}=\frac{i_1}{I_{U1}{\mathrm{<figure-callout\; id="1"\; label="I\; L"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">I</figure-callout>}}_L}=\mathrm{Cos}\left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}{2\mathrm{C\&pi;}}\mathrm{DL}\right).$

Step S6002: the normalized function relation according between the said first normalization monitoring current and normalization monitoring current and the chromatic dispersion accumulative total draws one group of chromatic dispersion aggregate-value with first specific period relation.

Can know, $\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}(2\mathrm{N\&pi;}\&PlusMinus;\mathrm{Arccos}{i}_{01}),$ Wherein, n is an integer, n=0, and 1,2,3 ...

Step S6003: the effective current value that reaches the upper and lower sideband monitor signal that is produced by the said second monitoring phone modulation according to said second monitoring current obtains the second normalization monitoring current.

That is, by i ₂, I _U2, I _L2Calculate $i_{02}=\frac{i_2}{I_{U2}{I}_{L2}}=\mathrm{Cos}\left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}{2\mathrm{C\&pi;}}\mathrm{DL}\right).$

Step S6004: the normalized function relation according between the said second normalization monitoring current and normalization monitoring current and the chromatic dispersion accumulative total draws one group of chromatic dispersion aggregate-value with second specific period relation.

Can know, $\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}(2\mathrm{M\&pi;}\&PlusMinus;\mathrm{Arccos}{i}_{02}),$ Wherein, m is an integer, m=0, and 1,2,3 ...

Step S6005: according to the said two groups chromatic dispersion aggregate-values that have the chromatic dispersion aggregate-value of specific period relation and confirm by the chromatic dispersion monitoring range of said two monitoring phones decision to monitor.

That is, of step S5003 among Fig. 4, confirm the chromatic dispersion aggregate-value of a unique equal DL value in the chromatic dispersion monitoring range for monitoring.

Through present embodiment, can make monitoring result not receive the influence of input power error, improve the precision of monitoring, and be convenient to operation.

Fig. 5 shows the monitoring result sketch map of the application implementation example of present embodiment.Wherein, the frequency of the first monitoring phone is f ₁=10GHZ, the frequency of the second monitoring phone is f ₂=4GHZ, the first normalization monitoring current value that monitors at receiving terminal is i ₀₁=0.95, the second normalization monitoring current value is i ₀₂=-0.22.Curve l ₁, l ₂Be respectively the first normalization monitoring current i ₀₁Function curve, the second normalization monitoring current i with DL ₀₂Function curve with DL.Because cosine function is a periodic function, for the uniqueness of monitoring result, set monitoring range, has only when real DL value is in this scope, the determined DL value of monitoring range and monitoring current is only accurately thus.Usually, the interval monitoring range for DL of preceding half period of getting function is interval, can be known that by figure the first monitoring DL monitoring range that phone determined does

Wherein, ω ₁=2 π f ₁, carrier wavelength lambda=1.55 μ m, the DL monitoring range that calculates the first monitoring phone decision is [0,0.6243] s/m; In like manner can get DL monitoring range [0, the 3.9022] s/m of the second monitoring phone decision.Can know that by figure though higher by the DL resolution of the first monitoring phone decision, the monitoring range of the DL of its decision is less than the DL monitoring range of the second monitoring factor decision.Equally, though the DL monitoring range of the second monitoring phone decision is higher, the DL resolution of its decision is less than the DL resolution of the first monitoring phone decision.This is the situation when using a monitoring phone separately, and in embodiments of the present invention, we use two monitoring phones to confirm DL.Can know curve l by figure ₁, l ₂The build-up curve that forms still is the periodic function curve, and its cycle is curve l ₁, l ₂The least common multiple in cycle then, is curve l by two monitoring ranges of monitoring the DL of the common decision of phones ₁, l ₂The pairing DL of the preceding half period of formed build-up curve is interval, that is: establish M and do

With

Least common multiple, then the monitoring ranges by the DL of the common decision of two monitoring phones are [0, M].In application implementation example shown in Figure 5, the monitoring range of DL is [0,15.6] s/m, the monitoring range of any one when this monitoring range is monitored phone greater than the independent use first monitoring phone or second.And, can know that by Fig. 5 should use among the embodiment, two monitoring DL resolution that phone determined are the resolution by the first monitoring phone decision, that is, and higher resolution in the two.

More than be the situation of the monitoring phone that uses two different frequencies,, can use the monitoring phone of three or more different frequencies to carry out the chromatic dispersion monitoring as other execution mode.The sketch map as a result that Fig. 6 carries out the chromatic dispersion monitoring for the monitoring phone that uses three different frequencies, the frequency of three monitoring phones is respectively: f ₁=10GHZ, f ₂=1.5GHZ, f ₃=1GHZ can be known by Fig. 6, as independent use f ₁The time, the DL scope that can monitor is [0,624ps/nm], if D=17ps/ (kmnm), the distance that then can monitor is 37km.When using three monitoring phones to monitor, the resolution of resulting DL is to use f separately ₁The time resolution, but monitoring range at this moment on the least common multiple 249.74e3ps/nm of the monitoring range upper limit when being limited to these three of independent uses monitoring phone.Suppose D=17ps/ (kmnm), for the situation of L=7000km, DL=120e3ps/nm then uses these three combination of frequencies can satisfy this monitoring range fully.

When using angular frequency to be respectively ω ₁, ω ₂..., ω _nN monitoring phone light carrier is modulated (n is an integer, and n>=2), and when using n monitoring current of this n monitoring phone correspondence to confirm the DL value, can know, be ω by frequency ₁The monitoring range of DL of monitoring phone decision do

By frequency is ω ₂The monitoring range of DL of monitoring phone decision do

..., be ω by frequency _nThe monitoring range of DL of monitoring phone decision do

If

Least common multiple be N, then, be ω by frequency ₁, ω ₂..., ω _nThe monitoring range of the DL that respectively monitors the common decision of phone be [0, N], in the resolution that the resolution of the DL that is monitored determines for each monitoring phone higher one.So,, under the situation that has guaranteed resolution, improved the monitoring range of chromatic dispersion accumulative total through the foregoing description of chromatic dispersion monitoring method of the present invention.

Correspondingly, the present invention also provides a kind of chromatic dispersion monitoring system, and as a kind of embodiment, this chromatic dispersion monitoring system can comprise modulating device, monitoring device and processing unit.Modulating device is used for using two or more monitoring phones of different frequency that light carrier is modulated at transmitting terminal; Monitoring device; Be used for extracting the upper and lower sideband monitor signal of respectively monitoring phone modulation generation from said light carrier by said at receiving terminal; And respectively each monitoring phone is modulated the upper and lower sideband monitor signal that produces and carry out mixing, obtain monitoring current corresponding to each monitoring phone; Processing unit is used for confirming the chromatic dispersion aggregate-value that monitors according to said each monitoring current.

Fig. 7 shows the functional module of its another embodiment and forms sketch map, includes modulating device 71, monitoring device 75 and processing unit 74, and wherein, monitoring device 75 includes extraction unit 72, mixing unit 73.

At receiving terminal, modulating device 71 uses the monitoring phone of two or more different frequencies that light carrier is modulated, the light carrier after the modulation through Optical Fiber Transmission to receiving terminal.At receiving terminal, extraction unit 72 extracts the upper and lower sideband monitor signal of respectively monitoring phone modulation generation by said from said light carrier.The corresponding upper and lower sideband monitor signal of phone of respectively monitoring that 73 pairs of mixing unit extract carries out mixing, filtering respectively, obtains the monitoring current corresponding to each monitoring phone.Processing unit 74 is confirmed the chromatic dispersion aggregate-value that monitors according to the functional relation of said each monitoring current and said each monitoring current and chromatic dispersion accumulative total.

As previously mentioned, monitoring current i becomes the cosine function relation with chromatic dispersion accumulative total DL, promptly

$i=A\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Wherein, A is the coefficient relevant with input power, and λ is an optical carrier wavelength, and ω is the angular frequency of monitoring phone.The monitoring range of chromatic dispersion accumulative total DL is determined by following formula:

$0\&le;\frac{D{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^{2}L}{2\mathrm{c\&pi;}}\&le;\mathrm{\&pi;}$

Hence one can see that, and the monitoring range of the DL of low more its decision of frequency of monitoring phone is just big more; In addition, can know that through the cosine function relation of monitoring current i and chromatic dispersion accumulative total DL the monitoring resolution of the DL of low more its decision of frequency of monitoring phone is just low more.

In the foregoing description of chromatic dispersion monitoring system of the present invention, modulating device adopts the monitoring phone of two or more different frequencies that light carrier is modulated, and establishes its angular frequency and is respectively ω ₁, ω ₂..., ω _n, then, monitoring current that obtains and the functional relation of DL are respectively:

$i_1=A\cos \left(\frac{{\mathrm{\&lambda;}}^2{{\mathrm{\&omega;}}_1}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right),$ $i_2=A\cos \left(\frac{{\mathrm{\&lambda;}}^2{{\mathrm{\&omega;}}_2}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right),$ ……， $i_n=A\cos \left(\frac{{\mathrm{\&lambda;}}^2{{\mathrm{\&omega;}}_n}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Then, can know, be ω by frequency ₁The monitoring range of DL of monitoring phone decision do

By frequency is ω ₂The monitoring range of DL of monitoring phone decision do

..., be ω by frequency _nThe monitoring range of DL of monitoring phone decision do

If

Least common multiple be N, then, be ω by frequency ₁, ω ₂..., ω _nThe monitoring range of the DL that respectively monitors the common decision of phone be [0, N], in the resolution that the resolution of the DL that is monitored determines for each monitoring phone higher one.So,, under the situation that has guaranteed resolution, improved the monitoring range of chromatic dispersion accumulative total through the foregoing description of chromatic dispersion monitoring system of the present invention.

The mode that modulating device 71 uses the monitoring phone of two or more different frequencies that light carrier is modulated comprises two kinds: a kind of is to use two or more monitoring phones of said different frequency that light carrier is modulated simultaneously, and a kind of is to use two or more monitoring phones of said different frequency that light carrier is modulated successively according to time sequencing.

Fig. 8 shows when adopting first kind of modulation system, and the functional module of an embodiment of chromatic dispersion monitoring system is formed sketch map.In the present embodiment; Modulating device 71 include with the corresponding a plurality of modulation modules 711,712 of each monitoring phone ..., 71n; Each modulation module uses corresponding monitoring phone that light carrier is modulated, and the light carrier after the modulation is coupled in the optical fiber and transmits.At receiving terminal, monitoring device 75 comprise equally with the corresponding a plurality of monitoring modulars 751,752 of each monitoring phone ..., 75n.Wherein, as a kind of execution mode, each monitoring modular all includes extraction module and frequency mixing module.Extraction module is responsible for from light carrier, extracting the upper and lower sideband monitor signal that the monitoring phone modulation by correspondence produces.Frequency mixing module is responsible for carrying out mixing, filtering to the upper and lower sideband monitor signal of the correspondence monitoring phone that extracts, and obtains the monitoring current corresponding to this monitoring phone.

As a kind of execution mode, extraction unit or each extraction module can be made up of optical coupler, upper sideband optical filter, lower sideband optical filter, upper sideband photodetector, lower sideband photodetector, upper sideband electrical filter, lower sideband electrical filter.Light carrier is divided into two bundles by optical coupler and gets into upper and lower sideband optical filter respectively; Obtain upper and lower sideband monitoring light signal; Obtain the upper and lower sideband monitoring signal of telecommunication through the opto-electronic conversion of upper and lower sideband photodetector respectively then; Pass through the electrofiltration ripple more respectively, the upper and lower sideband monitor signal that obtains extracting.

When Fig. 9 was second kind of modulation system of modulating device 71 employings, the functional module of an embodiment of chromatic dispersion monitoring system was formed sketch map.In the present embodiment; Because modulating device 71 uses the said phone of respectively monitoring that light carrier is modulated according to time sequencing successively, so, only need a modulation module 711 just enough; Correspondingly, the monitoring device 75 at receiving terminal also only needs a monitoring modular 751.But; Need increase a control unit 91 in the present embodiment; Be used to control modulating device 71 and use the said phone of respectively monitoring that said light carrier is modulated successively, control monitoring device 75 simultaneously and successively filtering bandwidth is switched to and the said corresponding bandwidth of phone of respectively monitoring according to same time sequencing according to time sequencing.

Figure 10 shows the functional module of the another embodiment of chromatic dispersion monitoring system of the present invention and forms sketch map.As a kind of execution mode, in the present embodiment, processing unit 74 includes first computing unit 741 and confirms unit 742.First computing unit 741 draws the chromatic dispersion aggregate-value that each group has the specific period relation respectively according to the monitoring current and the functional relation between monitoring current and DL corresponding to each monitoring phone of 73 outputs of mixing unit.Confirm that unit 742 has the chromatic dispersion aggregate-value of specific period relation and by said chromatic dispersion accumulative total monitoring range of respectively monitoring the phone decision, confirms the chromatic dispersion aggregate-value that monitors according to said each group.

As previously mentioned, angular frequency is that corresponding monitoring current i of the monitoring phone of ω and the functional relation of DL are:

$i=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_U{A}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Then, be respectively ω by angular frequency ₁, ω ₂... respectively monitor the corresponding monitoring current value i of phone ₁, i ₂... can determine the DL value that each group corresponding with each monitoring phone has period-luminosity relation respectively:

Corresponding to angular frequency is ω ₁The monitoring phone, $\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}(2\mathrm{N\&pi;}\&PlusMinus;\mathrm{<figure-callout\; id="10"\; label="Arccos\; i"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">Arccos</figure-callout>}\frac{i_{}}{}\frac{{}_{10}}{2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U1}{A}_{L1}}),$ Wherein, n is an integer, n=0,1,2,3......

Corresponding to angular frequency is ω ₂The monitoring phone, $\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}(2\mathrm{M\&pi;}\&PlusMinus;\mathrm{<figure-callout\; id="20"\; label="Arccos\; i"\; filenames="S07129744620070917E000041.png"\; state="\{\{state\}\}">Arccos</figure-callout>}\frac{i_{}}{}\frac{{}_{20}}{2{\left(\mathrm{RK}{A}_0\right)}^2{A}_{U2}{A}_{L2}}),$ Wherein, m is an integer, m=0,1,2,3......

Corresponding to angular frequency do ...

Because the DL value that each monitoring current is corresponding is identical, so, can confirm equal DL value the DL value from top respectively the group.The DL value that should equate still has a plurality of, but, as previously mentioned; The chromatic dispersion monitoring range of being confirmed jointly by each monitoring phone is [0; N], in this monitoring range, the DL value that equates has only unique one; Therefore, confirm that unit 742 can confirm that the DL value that equates in this chromatic dispersion monitoring range is the DL value that monitors.

Figure 11 forms sketch map for the functional module of another embodiment of chromatic dispersion monitoring system of the present invention.In the present embodiment, the chromatic dispersion monitoring system also includes effective value monitoring device 111, is used to monitor that extraction unit 72 extracts corresponding to the current effective value of the upper and lower sideband monitor signal of each monitoring phone.Processing unit 74 is except that comprising first computing unit 741 and confirming the unit 742; Also include second computing unit 743, be used for drawing corresponding normalization monitoring current according to current effective value that each monitoring current of mixing unit 73 output and effective value monitoring device 111 monitor corresponding to the upper and lower sideband monitor signal of each monitoring phone.First computing unit 741 draws the chromatic dispersion aggregate-value that each group has the specific period relation according to the normalized function relation between each normalization monitoring current and normalization monitoring current and the chromatic dispersion accumulative total.Confirm that unit 742 has the chromatic dispersion aggregate-value of specific period relation and by said chromatic dispersion accumulative total monitoring range of respectively monitoring the phone decision, confirms the chromatic dispersion aggregate-value that monitors according to said each group.

What from light carrier, extract as previously mentioned, is that the upper and lower sideband monitor signal of the monitoring phone of ω can be expressed as corresponding to angular frequency:

$i_U\left(t\right)=2\mathrm{RK}{A}_0{A}_U\cos (\mathrm{\&omega;}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1\mathrm{\&omega;}L-\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}^{2}L)$

$i_L\left(t\right)=2\mathrm{RK}{A}_0{A}_L\cos (\mathrm{\&omega;}t+{\mathrm{\&phi;}}_1+{\mathrm{\&phi;}}_{\mathrm{OF}}-{\mathrm{\&beta;}}_1\mathrm{\&omega;}L+\frac{1}{2}{\mathrm{\&beta;}}_2{\mathrm{\&omega;}}^{2}L)$

If i _U(t), i _L(t) current effective value is respectively I _U, I _L, then can know, $I_L=\sqrt{2}\mathrm{RK}{A}_0{A}_L,$ $I_U=\sqrt{2}\mathrm{RK}{A}_0{A}_U,$ First monitoring current that then above-mentioned two signals obtain after mixing, filtering is:

$i=2{\left(\mathrm{RK}{A}_0\right)}^2{A}_U{A}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)=I_U{I}_L\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Hence one can see that, if effective value monitoring device 111 can record the current effective value of the upper and lower sideband monitor signal that extracts, second computing unit 743 just can be obtained normalization monitoring current i according to the value of monitoring current i ₀Value:

$i_0=\frac{i}{I_U{I}_L}=\cos \left(\frac{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}^2}{2\mathrm{c\&pi;}}\mathrm{DL}\right)$

Can find out i by following formula ₀Value does not receive the influence of input power error, has improved the precision of monitoring.As a kind of execution mode, effective value monitoring device 111 can be realized through the current monitoring table.

First computing unit 741 is respectively ω according to what second computing unit 743 calculated corresponding to angular frequency ₁, ω ₂... the normalization monitoring current value i that respectively monitors phone ₀₁, i ₀₂..., determine the DL value that each group has period-luminosity relation:

Corresponding to angular frequency is ω ₁The monitoring phone, $\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_1^2}(2\mathrm{N\&pi;}\&PlusMinus;\mathrm{Arccos}{i}_{01}),$ Wherein, n is an integer, n=0, and 1,2,3 ...

Corresponding to angular frequency is ω ₂The monitoring phone, $\mathrm{DL}=\frac{2\mathrm{C\&pi;}}{{\mathrm{\&lambda;}}^2{\mathrm{\&omega;}}_2^2}(2\mathrm{M\&pi;}\&PlusMinus;\mathrm{Arccos}{i}_{02}),$ Wherein, m is an integer, m=0, and 1,2,3 ...

Corresponding to angular frequency do ...

Confirm that unit 742 the same embodiment are the same, determine a unique DL value according to the chromatic dispersion monitoring range.

To sum up; The embodiment of chromatic dispersion monitoring method provided by the invention, system and device; Under the situation that guarantees monitoring result resolution, improved the chromatic dispersion monitoring range; And obtain the normalization monitoring current through the current effective value that obtains upper and lower sideband, make monitoring result not receive the influence of input power error, improved the precision of monitoring.

Above disclosedly be merely preferred embodiment of the present invention, can not limit the present invention's interest field certainly with this, the equivalent variations of therefore doing according to claim of the present invention still belongs to the scope that the present invention is contained.

Claims (16)

1. a chromatic dispersion monitoring method is characterized in that, comprising:

At transmitting terminal, use two or more monitoring phones of different frequency that light carrier is modulated, and the light carrier after will modulating send through optical fiber;

At receiving terminal; Receive the light carrier after the said modulation; Therefrom extract the upper and lower sideband monitor signal of respectively monitoring phone modulation generation respectively by said; And respectively the upper and lower sideband monitor signal that is produced by each monitoring phone modulation that extracts is carried out mixing, obtain monitoring current corresponding to each monitoring phone;

Confirm the chromatic dispersion aggregate-value that monitors according to said each monitoring current.

2. chromatic dispersion monitoring method as claimed in claim 1; It is characterized in that the mode that two or more monitoring phones of said use different frequency are modulated light carrier is: use two or more monitoring phones of said different frequency that light carrier is modulated simultaneously.

3. chromatic dispersion monitoring method as claimed in claim 1; It is characterized in that the mode that two or more monitoring phones of said use different frequency are modulated light carrier is: use two or more monitoring phones of said different frequency successively light carrier to be modulated according to time sequencing.

4. chromatic dispersion monitoring method as claimed in claim 3; It is characterized in that, from said light carrier, extract respectively by said mode of respectively monitoring the upper and lower sideband monitor signal that phone modulation produces and be: from said light carrier, extract successively by said according to said time sequencing and respectively monitor the upper and lower sideband monitor signal that the phone modulation produces.

5. like each described chromatic dispersion monitoring method of claim 1 to 4, it is characterized in that the step of the chromatic dispersion aggregate-value of confirming according to said monitoring current to monitor specifically comprises:

Functional relation according between said each monitoring current and monitoring current and the chromatic dispersion accumulative total draws the chromatic dispersion aggregate-value that each group has period-luminosity relation respectively;

According to the chromatic dispersion aggregate-value that said each group has period-luminosity relation, reach the chromatic dispersion accumulative total monitoring range of respectively monitoring the phone decision by said, confirm the chromatic dispersion aggregate-value that monitors.

6. like each described chromatic dispersion monitoring method of claim 1 to 4, it is characterized in that the step of the chromatic dispersion aggregate-value of confirming according to said monitoring current to monitor specifically comprises:

Obtain normalization monitoring current according to said each monitoring current and by said effective current value of respectively monitoring the upper and lower sideband monitor signal of phone modulation generation corresponding to each monitoring current;

Functional relation according between said each normalization monitoring current and normalization monitoring current and the chromatic dispersion accumulative total draws the chromatic dispersion aggregate-value that each group has the specific period relation;

According to the chromatic dispersion aggregate-value that said each group has the specific period relation, reach the chromatic dispersion accumulative total monitoring range of respectively monitoring the phone decision by said, confirm the chromatic dispersion aggregate-value that monitors.

7. chromatic dispersion monitoring method as claimed in claim 6 is characterized in that:

Before the step that obtains according to said each monitoring current and by said effective current value of respectively monitoring the upper and lower sideband monitor signal that phone modulation produces corresponding to the normalization monitoring current of each monitoring current, comprise: obtain the effective current value of respectively monitoring the upper and lower sideband monitor signal that the phone modulation produces by said.

8. a chromatic dispersion monitoring system is characterized in that, comprising:

Modulating device is used for using two or more monitoring phones of different frequency that light carrier is modulated at transmitting terminal;

Monitoring device; Be used for extracting the upper and lower sideband monitor signal of respectively monitoring phone modulation generation from said light carrier by said at receiving terminal; And respectively each monitoring phone is modulated the upper and lower sideband monitor signal that produces and carry out mixing, obtain monitoring current corresponding to each monitoring phone;

Processing unit is used for confirming the chromatic dispersion aggregate-value that monitors according to said each monitoring current.

9. chromatic dispersion monitoring system as claimed in claim 8 is characterized in that, said monitoring device comprises:

Extraction unit is used for extracting the upper and lower sideband monitor signal of respectively monitoring phone modulation generation by said from said light carrier at receiving terminal;

The mixing unit is used for the upper and lower sideband monitor signal that is produced by each monitoring phone modulation that said extraction unit extracts is carried out mixing respectively, obtains the monitoring current corresponding to each monitoring phone.

10. chromatic dispersion monitoring system as claimed in claim 8; It is characterized in that; Also comprise control unit; Be used to control said modulating device and use the said phone of respectively monitoring that said light carrier is modulated successively, control said monitoring device simultaneously and successively its filtering bandwidth is switched to and the said corresponding bandwidth of phone of respectively monitoring according to same time sequencing according to time sequencing.

11. chromatic dispersion monitoring system as claimed in claim 8 is characterized in that:

Said modulating device includes each modulation module corresponding to each monitoring phone, and said each modulation module uses corresponding monitoring phone that light carrier is modulated respectively;

Said monitoring device includes each monitoring modular corresponding to each monitoring phone; Said each monitoring modular extracts the upper and lower sideband monitor signal that is produced by the modulation of correspondence monitoring phone respectively from said light carrier; And said upper and lower sideband monitor signal carried out mixing, obtain corresponding monitoring current.

12. chromatic dispersion monitoring system as claimed in claim 11 is characterized in that, said monitoring modular includes:

Extraction module is used for extracting the upper and lower sideband monitor signal that is produced by the modulation of correspondence monitoring phone from said light carrier;

Frequency mixing module is used for the said upper and lower sideband monitor signal that said extraction module extracts is carried out mixing, obtains corresponding monitoring current.

13. chromatic dispersion monitoring system as claimed in claim 9 is characterized in that, said processing unit specifically comprises:

First computing unit is used for drawing the chromatic dispersion aggregate-value that each group has the specific period relation respectively according to the functional relation between said each monitoring current and monitoring current and the chromatic dispersion accumulative total;

Confirm the unit, be used for having the chromatic dispersion aggregate-value of specific period relation and, confirming the chromatic dispersion aggregate-value that monitors by said chromatic dispersion accumulative total monitoring range of respectively monitoring the phone decision according to said each group.

14. chromatic dispersion monitoring system as claimed in claim 13 is characterized in that, also includes the effective value monitoring device, is used to monitor that said extraction unit extracts by said current effective value of respectively monitoring the upper and lower sideband monitor signal that the phone modulation produces;

Said processing unit also includes second computing unit, is used for drawing each normalization monitoring current according to said each monitoring current and by each current effective value of monitoring the upper and lower sideband monitor signal of phone modulation generation;

Wherein, said first computing unit draws the chromatic dispersion aggregate-value that each group has the specific period relation according to the normalized function relation between said each normalization monitoring current and normalization monitoring current and the chromatic dispersion accumulative total.

15. monitoring device; Include monitoring means; Be used for extracting the upper and lower sideband monitor signal that produces by said monitoring phone modulation at the light carrier that receiving terminal is modulated from monitored phone; And said upper and lower sideband monitor signal is carried out mixing obtain monitoring current, it is characterized in that, also include:

Control unit; Being used to control said monitoring means switches to filtering bandwidth and the corresponding bandwidth of each monitoring phone according to time sequencing successively; Said time sequencing is with consistent to the time sequencing that said light carrier is modulated successively at the said phone of respectively monitoring of transmitting terminal, saidly respectively monitors the monitoring phone that phone is two or more different frequencies.

16. monitoring device; Be used for extracting the upper and lower sideband monitor signal that produces by said monitoring phone modulation at the light carrier that receiving terminal is modulated from monitored phone; And said upper and lower sideband monitor signal is carried out mixing obtain monitoring current; It is characterized in that; Said monitoring device includes two or more monitoring means, and wherein, each monitoring means is used for extracting the upper and lower sideband that is produced by the monitoring phone modulation corresponding with it at receiving terminal from light carrier, and also said upper and lower sideband monitor signal is carried out mixing obtains corresponding monitoring current.

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