CN101895495B - Method and system for transmitting and receiving by orthogonally dual-polarized differential quaternary phase shift keying - Google Patents

Abstract

The invention relates to a method and a system for transmitting and receiving by orthogonally dual-polarized differential quaternary phase shift keying. The system comprises a transmitting device and a receiving device, wherein the transmitting device comprises a continuous laser; the continuous laser is connected with a polarization beam splitter which is connected with a DQPSK modulator; the DQPSK modulator is connected with a precoder of which the output end is connected with a tunable optical attenuator or a polarization controller; and the polarization controller is connected with a polarization beam combiner; and the receiving device comprises a DQPSK demodulator, and the DQPSK demodulator is connected with a balanced detector which is connected with a decision circuit. In the method, four paths of electrical signals can be multiplexed, and only one demodulator and two balanced detectors are used at a receiving end to demodulate two orthogonally polarized DQPSK signals at the same time; therefore, compared with D8PSK and x-QAM systems, the system has the advantages of greatly reducing the complexity and remarkably enhancing the stability of components.

Description

The emission of Orthogonal Double polarization differential quadrature phase keying (DQPSK) and the method and the system thereof that receive

Technical field

The present invention relates to digital communicating field, specifically a kind of Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission and the method and the system thereof that receive.

Background technology

Use multiple modulator approach in the digital communication system; Wherein heterogeneous key transposition system comes into one's own with its good availability of frequency spectrum and bit error rate performance; It is with the modulation format of information stores in the phase place that transmits that heterogeneous key moves; The demand that increases rapidly for high capacity communication along with information-intensive society, the operation of optical fiber communication circle at present commercial city with the system upgrade of single channel 10Gbit/s to the 40Gbit/s system, the while is also for being upgraded to 100Gbit/s even 160Gbit/s system accumulation technology.

The method that reaches the 100Gbit/s optical transmission system at present mainly contains wavelength-division multiplex technique, time-division multiplex technology, divides multiplex technique, symbol multiplex technique etc. partially.Wherein single wavelength accomplishes that 40Gbit/s is until the then general symbolization multiplex technique of 100Gbit/s system.Common symbol multiplex technique has: differential quadrature phase keying (DQPSK) (DQPSK), difference octaphase-shift keying (D8PSK), multistage quadrature amplitude modulation (x-QAM) etc.Prior art has following shortcoming: difference octaphase-shift keying (D8PSK), multistage quadrature amplitude modulation (x-QAM) are though the signal of telecommunication that the sign indicating number type can carry out more than 3 tunnel is multiplexing; But transmit and receive all super complicacy of part-structure; And some special components and parts stability is also not good, is difficult to accomplish precise and stable like π/8 phase-shifters of using in the D8PSK demodulator; Several Mach-Zehnder modulators (MZM) of using in the multiplexer also are difficult to accomplish complete symmetry; Moreover the demodulating system of D8PSK uses 4 road Mach-Zehnder interferometer light paths, 4 balance detection devices and a NOR gate circuit, and is very complicated.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission and the method and the system thereof that receive, and it not only reduces complexity greatly, and components and parts stability is significantly strengthened.

For achieving the above object; Technical scheme of the present invention is achieved in that a kind of Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission and receiving system; Comprise emitter and receiving system; It is characterized in that described emitter comprises: be used to export the continuous wave laser of continuous light as light carrier; Described continuous wave laser is connected with the polarization beam apparatus that is used for the continuous light of incident is divided into the orthogonal two bunch polarised lights of polarization state; Described polarization beam apparatus is connected with a DQPSK modulator, the 2nd DQPSK modulator; The input of a described DQPSK modulator, the 2nd DQPSK modulator connects precoder; The output of a described DQPSK modulator connects first Polarization Controller; The output of described the 2nd DQPSK modulator connects variable optical attenuator, and the output of described variable optical attenuator connects second Polarization Controller; The output of described first Polarization Controller, second Polarization Controller is connected with polarization beam combiner.

Described receiving system comprises: the DQPSK demodulator, and it is connected with the output of emitter; The balance detection device, its output with the DQPSK demodulator is connected; Decision circuit, its output with the balance detection device is connected.

The one DQPSK modulator of said emitter comprises: in order to receive modulation signal I respectively _1k, Q _1kTwo Mach-Zehnder modulators, it is connected with the first pi/2 phase shift device.

The 2nd DQPSK modulator of said emitter comprises: in order to receive modulation signal I respectively _2k, Q _2kTwo Mach-Zehnder modulators, it is connected with the second pi/2 phase shift device.

The output of the polarization beam combiner of said emitter also is connected with Mach-Zehnder modulators.

The DQPSK demodulator of said receiving system comprises: coupler, described coupler connect the first Mach-Zehnder delay interferometer, the second Mach-Zehnder delay interferometer.

Corresponding 1 bit period of the upper arm of the described first Mach-Zehnder delay interferometer postpones, the phase shift of the corresponding π of underarm/4; Corresponding 1 bit period of the upper arm of the described second Mach-Zehnder delay interferometer postpones the phase shift of underarm correspondence-π/4.

The balance detection device of said receiving system comprises: the first balance detection device, and its output with the first Mach-Zehnder delay interferometer is connected; The second balance detection device, its output with the second Mach-Zehnder delay interferometer is connected.

The described first balance detection device comprises: two photodetectors are used for receiving respectively the light signal from the first Mach-Zehnder delay interferometer " add mouthful " and " subtract mouthful ", subtracter of output connection of photodetector; The described second balance detection device comprises: two photodetectors are used for receiving respectively the light signal from the second Mach-Zehnder delay interferometer " add mouthful " and " subtract mouthful ", subtracter of output connection of photodetector.

A kind of Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission and method of reseptance is characterized in that described step of transmitting comprises: continuous wave laser output continuous light is as light carrier; Be input to up and down on two DQPSK modulators through polarization beam apparatus; The precoder input receives from four road voltage signal u of signal generator output output _1k, v _1k, u _2k, v _2k, its coding is become modulation signal I _1k, Q _1k, I _2k, Q _2kModulation signal I _1k, Q _1kBe loaded into a DQPSK modulator, and output to first Polarization Controller by optical output port; Modulation signal I _2k, Q _2kBe loaded into the 2nd DQPSK modulator, and output to variable optical attenuator by optical output port and carry out optical power adjustment, the ratio of power of the DQPSK signal of first branch road and second branch road was satisfied 2: 1, and then output to second Polarization Controller; The polarization signal light of restrainting quadratures from two of first Polarization Controller and the output of second Polarization Controller is coupled through polarization beam combiner, obtains Orthogonal Double polarization non-return-to-zero DQPSK signal; Modulation obtains Orthogonal Double polarization (RZ) DQPSK signal that makes zero through Mach-Zehnder modulators again.

Described receiving step comprises: the flashlight after the reception gets into the first Mach-Zehnder delay interferometer and the second Mach-Zehnder delay interferometer is carried out the demodulation of DQPSK signal through coupler; Two input ports of the first balance detection device receive respectively from the first Mach-Zehnder delay interferometer and " add mouth " and the light signal of " subtracting mouth ", and photodetector changes light signal into electric current, output signal of telecommunication u after two current subtraction; Two input ports of the second balance detection device receive rice respectively and " add mouth " and the light signal of " subtracting mouth " from the second Mach-Zehnder delay interferometer, and photodetector changes light signal into electric current, output signal of telecommunication v after two current subtraction; The signal of telecommunication of output gets into decision circuit and adjudicates the data after obtaining at last transmitting.

Described step of transmitting is obtained I according to the precoding formula _1k, Q _1k, I _2k, Q _2kModulation signal:

${\mathrm{<figure-callout\; id="1"\; label="I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">I</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{I}_{}{}_{1,k-1}}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}\stackrel{\&OverBar;}{v_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{I}_{1,k-1}$

${\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}\stackrel{}{I_{}}\stackrel{\&OverBar;}{{}_{1,k-1}}+u_{1,k}\stackrel{\&OverBar;}{v_{1,k}}{I}_{1,k-1}+u_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}$

$I_{2,k}=\stackrel{\&OverBar;}{v_{1,k}{v}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{u}_{2,k}{I}_{2,k-1}}{Q}_{2,k-1}+\stackrel{\&OverBar;}{v_{1,k}}{v}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}+v_{1,k}\stackrel{\&OverBar;}{v_{2,k}}{I}_{2,k-1}{Q}_{2,k-1}$

$+{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}{v}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{u}_{2,k}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+u_{1,k}\stackrel{\&OverBar;}{u_{2,k}}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+u_{1,k}{u}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}$

$Q_{2,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{u}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}}+\stackrel{\&OverBar;}{v_{1,k}{v}_{2,k}}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+\stackrel{\&OverBar;}{v_{1,k}}{v}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}+v_{1,k}\stackrel{\&OverBar;}{v_{2,k}{I}_{2,k-1}}{Q}_{2,k-1}$

$+{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}{v}_{2,k}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{u}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}+u_{1,k}\stackrel{\&OverBar;}{u_{2,k}}{I}_{2,k-1}{Q}_{2,k-1}{+u}_{1,k}{u}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}$ Or

${\mathrm{<figure-callout\; id="1"\; label="I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">I</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{I}_{}{}_{1,k-1}}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}\stackrel{\&OverBar;}{v_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{I}_{1,k-1}$

${\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}\stackrel{}{I_{}}\stackrel{\&OverBar;}{{}_{1,k-1}}+u_{1,k}\stackrel{\&OverBar;}{v_{1,k}}{I}_{1,k-1}+u_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}$

$I_{2,k}=\left(\begin{array}{ccc}{v}_{1,k}& e& v_{2,k}\end{array}\right)\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}+(u_{1,k}\&CirclePlus;u_{2,k})I_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}$

$+\left(\begin{array}{ccc}{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}& e& u_{2,k}\end{array}\right)\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}+(v_{1,k}\&CirclePlus;v_{2,k})I_{2,k-1}{Q}_{2,k-1}$

$Q_{2,k}=\left(\begin{array}{ccc}{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}& e& u_{2,k}\end{array}\right)\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}+\left(\begin{array}{ccc}{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}& e& v_{2,k}\end{array}\right)I_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}$

$+(v_{1,k}\&CirclePlus;v_{2,k})\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}+(u_{1,k}\&CirclePlus;u_{2,k})I_{2,k-1}{Q}_{2,k-1}.$

The decision method that decision circuit carries out in the described receiving step does, from formula:

$V_{\mathrm{DPol}-\mathrm{QPSK},\frac{\mathrm{\&pi;}}{4}}\&Proportional;\left|I_{\mathrm{Desstructive}.\frac{\mathrm{\&pi;}}{4}}\right|-\left|I_{\mathrm{Constructive}.\frac{\mathrm{\&pi;}}{4}}\right|$

$=R\frac{2P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{u1}\right)-\sin \left({\mathrm{\&Delta;\&phi;}}_{u1}\right)]+R\frac{P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{u2}\right)-\sin \left({\mathrm{\&Delta;\&phi;}}_{u2}\right)]$

$V_{\mathrm{DPol}-\mathrm{QPSK},-\frac{\mathrm{\&pi;}}{4}}\&Proportional;\left|I_{\mathrm{Desstructive}.-\frac{\mathrm{\&pi;}}{4}}\right|-\left|I_{\mathrm{Constructive}.-\frac{\mathrm{\&pi;}}{4}}\right|$

$=R\frac{2P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{v1}\right)+\sin \left({\mathrm{\&Delta;\&phi;}}_{v1}\right)]+R\frac{P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{v2}\right)+\sin \left({\mathrm{\&Delta;\&phi;}}_{v2}\right)]$

Wherein R is the responsiveness of photodiode, and P is the total luminous power of incoming signal

Obtain the relative level-1 of four different amplitudes ,-1/3,1/3,1, (the u that different relative level values is corresponding different ₁, u ₂) and (v ₁, v ₂) combinational code, wherein relative level-1 is corresponding 00, relative level-1/3 is corresponding 01, relative level 1/3 is corresponding 11, relative level 1 corresponding 10.Realize three relative decision level-2/3,0,2/3, when the relative value of output level during less than-2/3 relative level, judgement is output as 00; When the relative value of output level greater than-2/3 less than 0 the time, judgement is output as 01; When the relative value of output level greater than 0 less than 2/3 the time, judgement is output as 11; When the relative value of output level greater than 2/3, then judgement is output as 10, thereby demodulates four road signal of telecommunication u ₁, v ₁, u ₂, v ₂

The present invention has following outstanding substantive distinguishing features and obvious improvement with respect to prior art:

Can multiplexing 4 road signals of telecommunication; And receiving terminal only needs just can the DQPSK signal demodulation simultaneously of two cross-polarizations to be come out with a demodulator and two balance detection devices; Compare with D8PSK and x-QAM system, complexity reduces greatly, and components and parts stability is significantly strengthened.

Description of drawings

Fig. 1 is an emitter structure chart of the present invention;

Fig. 2 is a receiving system structure chart of the present invention;

Fig. 3 is an Orthogonal Double polarization DQPSK signal constellation which;

Fig. 4 is the spectrogram of Orthogonal Double polarization DQPSK signal;

Fig. 5 is a receiving terminal Orthogonal Double polarization DQPSK eye pattern

Embodiment

As shown in Figure 1, the continuous light of the continuous wave laser of emitter of the present invention output is as light carrier, is input to up and down on two DQPSK modulators modulated through polarization beam apparatus; The effect of polarization beam apparatus is that the continuous light with incident is divided into the orthogonal two bunch polarised lights of polarization state; Each DQPSK modulator is by two Mach-Zehnder modulators and a pi/2 phase shift device are formed up and down; Its microwave signal input receives the data flow of precoder output, realizes the non-return-to-zero DQPSK signal modulation of light territory and outputs to Polarization Controller or variable optical attenuator by optical output port; The variable optical attenuator light inlet receives from the light signal after the modulation of branch road DQPSK modulator output down, the luminous power of adjustment input signal, and making up and down, the ratio of the power of the DQPSK signal of branch road satisfied 2: 1; Polarization Controller is used for controlling the signal polarization state of light that incides on the polarization beam combiner, guarantees to incide the signal polarization state of light quadrature on the polarization beam combiner; The effect of polarization beam combiner is being optically coupled in together from the polarization signal of two bundle quadratures of two Polarization Controllers outputs of branch road up and down, obtaining Orthogonal Double polarization non-return-to-zero (NRZ) DQPSK signal; If will obtain Orthogonal Double polarization (RZ) DQPSK signal that makes zero; Also will be through a Mach-Zehnder modulators modulation; Add different bias voltage and clock signal to Mach-Zehnder modulators, just can obtain the Orthogonal Double polarization RZ-DQPSK signal of different duty; The precoder input receives from four road voltage signals of signal generator output output, and with four road voltage signal u _1k, v _1k, u _2k, v _2kCoding becomes I _1k, Q _1k, I _2k, Q _2kModulation signal, the modulation signal output of this precoder connect the modulated terminal of two DQPSK modulators up and down respectively, as being loaded into the microwave data source of two DQPSK modulators up and down; 4 road signal of telecommunication u _1k, v _1k, u _2k, v _2k, become and be I through precoding formula (1) or (2) _1k, Q _1k, I _2k, Q _2kModulation signal, the precoding formula is:

(1) the precoding formula table is shown as the form of AOI:

${\mathrm{<figure-callout\; id="1"\; label="I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">I</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{I}_{}{}_{1,k-1}}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}\stackrel{\&OverBar;}{v_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{I}_{1,k-1}$

${\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}\stackrel{}{I_{}}\stackrel{\&OverBar;}{{}_{1,k-1}}+u_{1,k}\stackrel{\&OverBar;}{v_{1,k}}{I}_{1,k-1}+u_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}$

$I_{2,k}=\stackrel{\&OverBar;}{v_{1,k}{v}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{u}_{2,k}{I}_{2,k-1}}{Q}_{2,k-1}+\stackrel{\&OverBar;}{v_{1,k}}{v}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}+v_{1,k}\stackrel{\&OverBar;}{v_{2,k}}{I}_{2,k-1}{Q}_{2,k-1}$ (1)

$+{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}{v}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{u}_{2,k}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+u_{1,k}\stackrel{\&OverBar;}{u_{2,k}}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+u_{1,k}{u}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}$

$Q_{2,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{u}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}}+\stackrel{\&OverBar;}{v_{1,k}{v}_{2,k}}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+\stackrel{\&OverBar;}{v_{1,k}}{v}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}+v_{1,k}\stackrel{\&OverBar;}{v_{2,k}{I}_{2,k-1}}{Q}_{2,k-1}$

$+{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}{v}_{2,k}{I}_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{u}_{2,k}{I}_{2,k-1}{Q}_{2,k-1}+u_{1,k}\stackrel{\&OverBar;}{u_{2,k}}{I}_{2,k-1}{Q}_{2,k-1}{+u}_{1,k}{u}_{2,k}\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}$

(2) the precoding formula table be shown as with or with the form of XOR:

${\mathrm{<figure-callout\; id="1"\; label="I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">I</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{I}_{}{}_{1,k-1}}+\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}\stackrel{\&OverBar;}{v_{1,\mathrm{<figure-callout\; id="1"\; label="k\; Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}{Q}_{}{}_{1,k-1}}+{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{I}_{1,k-1}$

${\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k}=\stackrel{\&OverBar;}{{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}}+\stackrel{\&OverBar;}{u_{1,k}}{v}_{1,\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">k</figure-callout>}}\stackrel{}{I_{}}\stackrel{\&OverBar;}{{}_{1,k-1}}+u_{1,k}\stackrel{\&OverBar;}{v_{1,k}}{I}_{1,k-1}+u_{1,k}{v}_{1,k}{\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{1,k-1}$

$I_{2,k}=\left(\begin{array}{ccc}{v}_{1,k}& e& v_{2,k}\end{array}\right)\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}+(u_{1,k}\&CirclePlus;u_{2,k})I_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}$ (2)

$+\left(\begin{array}{ccc}{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}& e& u_{2,k}\end{array}\right)\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}+(v_{1,k}\&CirclePlus;v_{2,k})I_{2,k-1}{Q}_{2,k-1}$

$Q_{2,k}=\left(\begin{array}{ccc}{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}& e& u_{2,k}\end{array}\right)\stackrel{\&OverBar;}{I_{2,k-1}{Q}_{2,k-1}}+\left(\begin{array}{ccc}{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}& e& v_{2,k}\end{array}\right)I_{2,k-1}\stackrel{\&OverBar;}{Q_{2,k-1}}$

$+({\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">v</figure-callout>}}_{1,k}\&CirclePlus;v_{2,k})\stackrel{\&OverBar;}{I_{2,k-1}}{Q}_{2,k-1}+({\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HSA00000190240300011.png,HSA00000190240300021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{1,k}\&CirclePlus;u_{2,k})I_{2,k-1}{Q}_{2,k-1}$

As shown in Figure 2, receiving system of the present invention is made up of a DQPSK demodulator, two balance detection devices and decision circuit.Flashlight after the transmission gets into two Mach-Zehnder delay interferometer through coupler; The upper arm of Mach-Zehnder delay interferometer is that 1 bit period postpones, and underarm is the phase shift of corresponding π/4 and-π/4 respectively, and it is used for realizing the demodulation of DQPSK signal; The output of each Mach-Zehnder delay interferometer links to each other with a balance detection device; The balance detection device is made up of two photodetectors and a subtracter; Its two input ports receive respectively from the Mach-Zehnder delay interferometer and " add mouth " and the light signal of " subtracting mouth "; Photodetector changes light signal into electric current, exports the signal of telecommunication after two current subtraction; The signal of telecommunication of output gets into decision circuit and adjudicates the data after obtaining at last transmitting.

With reference to Fig. 3 to Fig. 5, DQPSK demodulator of the present invention realizes that the principle of two-way quadrature DQPSK signal demodulation is: two ways of optical signals polarization state quadrature, not interfere each other, and the electric current of balance detection device output is the simple addition of pairwise orthogonal polarization state electric current.By the balance detection device be input to decision circuit 1. and the level of 2. locating can be expressed as:

$V_{\mathrm{DPol}-\mathrm{QPSK},\frac{\mathrm{\&pi;}}{4}}\&Proportional;\left|I_{\mathrm{Desstructive}.\frac{\mathrm{\&pi;}}{4}}\right|-\left|I_{\mathrm{Constructive}.\frac{\mathrm{\&pi;}}{4}}\right|$

$=R\frac{2P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{u1}\right)-\sin \left({\mathrm{\&Delta;\&phi;}}_{u1}\right)]+R\frac{P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{u2}\right)-\sin \left({\mathrm{\&Delta;\&phi;}}_{u2}\right)]$ (3)

$V_{\mathrm{DPol}-\mathrm{QPSK},-\frac{\mathrm{\&pi;}}{4}}\&Proportional;\left|I_{\mathrm{Desstructive}.-\frac{\mathrm{\&pi;}}{4}}\right|-\left|I_{\mathrm{Constructive}.-\frac{\mathrm{\&pi;}}{4}}\right|$

$=R\frac{2P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{v1}\right)+\sin \left({\mathrm{\&Delta;\&phi;}}_{v1}\right)]+R\frac{P}{3}[\cos \left({\mathrm{\&Delta;\&phi;}}_{v2}\right)+\sin \left({\mathrm{\&Delta;\&phi;}}_{v2}\right)]$

Wherein R is the responsiveness of photodiode, and P is the total luminous power of incoming signal.Can obtain the relative level-1 of four different amplitudes from formula (3) ,-1/3,1/3,1, (the u that different relative level values is corresponding different ₁, u ₂) and (v ₁, v ₂) combinational code, wherein relative level-1 is corresponding 00, relative level-1/3 is corresponding 01, relative level 1/3 is corresponding 11, relative level 1 corresponding 10; And such corresponding relation also meets the logical order of Gray code, and promptly the pairing adjacent interblock of adjacent levels has only a difference; The relative level of output and the corresponding relation of signal code stream are as shown in table 1.Because output is the relative level of four different amplitudes, design the adaptive decision circuit that three decision level are arranged, thereby demodulate four road signal of telecommunication u ₁, v ₁, u ₂, v ₂This decision circuit will have three relative decision level-2/3,0,2/3, and when the relative value of output level during less than-2/3 relative level, judgement is output as 00; When the relative value of output level greater than-2/3 less than 0 the time, judgement is output as 01; When the relative value of output level greater than 0 less than 2/3 the time, judgement is output as 11; When the relative value of output level greater than 2/3, then judgement is output as 10.

The corresponding signal code of table 14 output level

u 1，u 2Combinational code or v 1，v 2Combinational code	Output level
		00	-1
01	-1/3
		11	1/3
10	1

The above is merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention.

Claims (8)

1. an Orthogonal Double polarization differential quadrature phase keying (DQPSK) is launched and receiving system, comprises emitter and receiving system, it is characterized in that described emitter comprises:

Be used to export the continuous wave laser of continuous light as light carrier;

Described continuous wave laser is connected with the polarization beam apparatus that is used for the continuous light of incident is divided into the orthogonal two bunch polarised lights of polarization state;

Described polarization beam apparatus is connected with a DQPSK modulator, the 2nd DQPSK modulator;

The input of a described DQPSK modulator, the 2nd DQPSK modulator connects precoder;

The output of a described DQPSK modulator connects first Polarization Controller;

The output of described the 2nd DQPSK modulator connects and is used to adjust luminous power and makes up and down that the power ratio of two branch road DQPSK signals reaches 2: 1 variable optical attenuator, and the output of described variable optical attenuator connects second Polarization Controller;

The output of described first Polarization Controller, second Polarization Controller is connected with polarization beam combiner;

Described Polarization Controller is used to control the signal polarization state of light that incides on the polarization beam combiner, guarantees to incide the signal polarization state of light quadrature on the polarization beam combiner;

Described polarization beam combiner is used for being optically coupled in the polarization signal of restrainting quadratures from two of two Polarization Controller outputs together, obtains Orthogonal Double polarization DQPSK signal;

Described receiving system comprises:

The DQPSK demodulator, it is connected with the output of emitter; This DQPSK demodulator comprises: coupler, described coupler connect the first Mach-Zehnder delay interferometer, the second Mach-Zehnder delay interferometer; Corresponding 1 bit period of the upper arm of the described first Mach-Zehnder delay interferometer postpones, the phase shift of the corresponding π of underarm/4; Corresponding 1 bit period of the upper arm of the described second Mach-Zehnder delay interferometer postpones the phase shift of underarm correspondence-π/4;

The balance detection device, its output with the DQPSK demodulator is connected, and the number of described balance detection device is two;

Decision circuit, its output with the balance detection device is connected.

2. Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission as claimed in claim 1 and receiving system is characterized in that a DQPSK modulator of said emitter comprises: in order to receive modulation signal I respectively _1k, Q _1kTwo Mach-Zehnder modulators, and connect modulation signal I _1kThe first pi/2 phase shift device of Mach-Zehnder modulators;

The 2nd DQPSK modulator of said emitter comprises: in order to receive modulation signal I respectively _2k, Q _2kTwo Mach-Zehnder modulators, and connect modulation signal I _2kThe second pi/2 phase shift device of Mach-Zehnder modulators.

3. Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission as claimed in claim 2 and receiving system is characterized in that the output of the polarization beam combiner of said emitter also is connected with Mach-Zehnder modulators.

4. Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission as claimed in claim 3 and receiving system is characterized in that the balance detection device of said receiving system comprises: the first balance detection device, and its output with the first Mach-Zehnder delay interferometer is connected;

The second balance detection device, its output with the second Mach-Zehnder delay interferometer is connected.

5. Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission as claimed in claim 4 and receiving system; It is characterized in that; The described first balance detection device comprises: two photodetectors and a subtracter; Two photodetectors are used for receiving respectively from the first Mach-Zehnder delay interferometer and add mouthful and the light signal that subtracts mouthful, the signal of telecommunication that is used for two photodetectors outputs be input to subtracter subtract each other after output again;

The described second balance detection device comprises: two photodetectors and a subtracter; Two photodetectors are used for receiving respectively from the second Mach-Zehnder delay interferometer and add mouthful and the light signal that subtracts mouthful, the signal of telecommunication that is used for two photodetectors outputs be input to subtracter subtract each other after output again.

6. an Orthogonal Double polarization differential quadrature phase keying (DQPSK) is launched and method of reseptance, it is characterized in that described step of transmitting comprises:

Continuous wave laser output continuous light is as light carrier;

Be input on a DQPSK modulator, the 2nd DQPSK modulator through polarization beam apparatus;

The precoder input receives from four road voltage signal u of signal generator output output _1k, v _1k, u _2k, v _2k, its coding is become modulation signal I _1k, Q _1k, I _2k, Q _2k

Modulation signal I _1k, Q _1kBe loaded into a DQPSK modulator, obtain the DQPSK signal of first branch road, and output to first Polarization Controller by optical output port; Modulation signal I _2k, Q _2kBe loaded into the 2nd DQPSK modulator; Obtain the DQPSK signal of second branch road; And output to variable optical attenuator by optical output port and carry out optical power adjustment, the ratio of power of the DQPSK signal of first branch road and second branch road was satisfied 2: 1, and then output to second Polarization Controller;

The polarization signal light of restrainting quadratures from two of first Polarization Controller and the output of second Polarization Controller is coupled through polarization beam combiner, obtains Orthogonal Double polarization non-return-to-zero DQPSK signal; If modulation obtains the Orthogonal Double polarization DQPSK signal that makes zero through Mach-Zehnder modulators again;

Described receiving step comprises:

Flashlight after the reception gets into the first Mach-Zehnder delay interferometer and the second Mach-Zehnder delay interferometer is carried out the demodulation of DQPSK signal through coupler;

Two input ports of the first balance detection device receive respectively from the first Mach-Zehnder delay interferometer and add mouth and the light signal that subtracts mouth, and the photodetector in the balance detection device changes light signal into electric current, output signal of telecommunication u after two current subtraction; Two input ports of the second balance detection device receive respectively from the second Mach-Zehnder delay interferometer and add mouth and the light signal that subtracts mouth, and the photodetector in the balance detection device changes light signal into electric current, output signal of telecommunication v after two current subtraction;

The signal of telecommunication of output gets into decision circuit and adjudicates the data after obtaining at last transmitting.

7. Orthogonal Double polarization differential quadrature phase keying (DQPSK) emission as claimed in claim 6 and method of reseptance is characterized in that described step of transmitting is obtained I according to the precoding formula _1k, Q _1k, I _2k, Q _2kModulation signal:

8. Orthogonal Double polarization differential quadrature phase keying (DQPSK) as claimed in claim 7 emission and method of reseptance is characterized in that, the decision method that decision circuit carries out in the described receiving step does, from formula:

Wherein R is the responsiveness of photodiode, and P is the relative level-1 that the total luminous power of incoming signal obtains four different amplitudes ,-1/3,1/3,1, and the u that different relative level values is corresponding different ₁, u ₂And v ₁, v ₂Combinational code, wherein relative level-1 is corresponding 00, relative level-1/3 is corresponding 01, relative level 1/3 corresponding 11; Relative level 1 correspondence 10 realizes three relative decision level-2/3,0; 2/3, when the relative value of output level during less than-2/3 relative level, judgement is output as 00; When the relative value of output level greater than-2/3 less than 0 the time, judgement is output as 01; When the relative value of output level greater than 0 less than 2/3 the time, judgement is output as 11; When the relative value of output level greater than 2/3, then judgement is output as 10, thereby demodulates four road signal of telecommunication u ₁, v ₁, u ₂, v ₂

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