CN206610038U - A kind of direct current biasing working point control loop of mach zhender intensity modulator - Google Patents
A kind of direct current biasing working point control loop of mach zhender intensity modulator Download PDFInfo
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- CN206610038U CN206610038U CN201621467944.0U CN201621467944U CN206610038U CN 206610038 U CN206610038 U CN 206610038U CN 201621467944 U CN201621467944 U CN 201621467944U CN 206610038 U CN206610038 U CN 206610038U
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- intensity modulator
- mach zhender
- frequency
- signal
- direct current
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Abstract
The utility model is a kind of direct current biasing working point control loop of mach zhender intensity modulator (MZM), light transmitting terminal laser optical signal sends into MZM, modulation signal sends into MZM modulation ports, MZM light outputs connect the photodetector of optical receiving end through long optical fibers, recover modulation signal output.MZM offset ports connect DC offset voltage circuit and reference electrical signal F1And F2；The photo-detector of optical receiving end is also connected with feedback control circuit, and the circuit includes narrow-band filter, A-D converter and each 2 of logafier and comparator.The electric signal fraction of recovery obtains F through 2 narrow-band filters1With third order intermodulation signal 2F1‑F2, after analog to digital conversion and amplification, comparator is accessed, third order intermodulation inhibiting value IM3 is obtained and sends the DC offset voltage circuit that transmitting terminal accesses MZM through light-to-current inversion back to.The whole of the utility model IM3 reflection systems is non-linear, automatic amendment MZM DC offset voltage, locks its best operating point.
Description
Technical field
The utility model is related to technical field of photo communication, specially a kind of mach zhender intensity modulator (MZM) it is straight
Flow offset operation point control loop.
Background technology
Lithium niobate mach zhender intensity modulator (MZM) is the light external modulator commonly used in optical communication link, main to use
In the demand for meeting long range high-speed optical transmission.The MZM approximate cosine curve of transfer function, thus be it is nonlinear, it is this non-
It is linearly one of the limitation principal element of analog electrical signal without spuious dynamic indicator.Generally MZM direct current biasing operating point is set
Put in some optimum operating voltage corresponding to the curve, when modulation electrical input signal is changed centered on the biased electrical pressure point
When, it will be changed by the optical signal of modulation output substantially according to rule corresponding with modulation signal, so as to realize the modulation of information.
Due to such environmental effects such as temperature and external electrical fields, MZM transfer function curve easily drifts about.When transfer function curve
Produce drift when, if DC offset voltage value be also to maintain it is constant, because modulated signal will surround best operating point
Change, the quality of final influence modulated signal.Therefore MZM needs special dc bias control loop to solve drifting problem,
Ensure MZM best operating point locking.
Conventional direct current biasing stabilization of operating point scheme is to use feedback control at present, existing various feedback control mode
It is substantially all and is only applied to high-speed digital signal (such as QPSK) light external modulation link, recovered with photo-detector after electric signal, is led to
The change of monitoring second harmonic or fundamental signal amplitude is crossed, direct current biasing operating point is locked in the 4 of MZM transfer function curve
On individual particular point (such as orthogonal points, minimum point or peak), to obtain relatively low digital signal bit error rate, but this method is not
It is appropriate to long range broadband analogue optical transmission system.
Utility model content
In view of problems of the prior art, main purpose of the present utility model is the defect for solving prior art,
A kind of direct current biasing working point control loop of mach zhender intensity modulator (MZM) is provided, MZM optimum operating voltages are monitored
Skew caused by third order intermodulation suppress value changes, then using feedback circuit control MZM DC offset voltage change, from
And mach zhender intensity modulator is locked in best operating point.The circuit suppresses the non-linear of mach zhender intensity modulator
Caused third order intermodulation distortion, it is adaptable in long range broadband analogue optical transmission system, with obtain optimal analog electrical signal without
Spuious dynamic range.
A kind of direct current biasing working point control for mach zhender intensity modulator (MZM) that the utility model is provided is returned
Road, includes the light transmitting terminal and optical receiving end of 100km~500km long optical fibers connection, and in light transmitting terminal, the output of laser connects
The light input end mouthful of mach zhender intensity modulator is connected to, frequency is FIN=300MHz~30GHz modulation signal quilt
The modulation port of mach zhender intensity modulator is input to, direct current is connected in the offset port of mach zhender intensity modulator
Bias voltage circuit, the photoelectricity that the optical output port of mach zhender intensity modulator connects optical receiving end through the long optical fibers is visited
Electric signal is recovered after survey device, opto-electronic conversion and passes through high-pass filter, is obtained modulation signal and is output.
Due to mach zhender intensity modulator transfer function it is non-linear, during Electro-optical Modulation will produce three ranks
Intermodulation signal, its frequency is respectively 2F1-F2And 2F2-F1.The biasing of the light transmitting terminal mach zhender intensity modulator in this loop
Port is also connected with frequency respectively F1And F2The first reference electrical signal and the second reference electrical signal, F1Or F2It is below modulation electricity
Signal frequency FIN, and be all higher than or equal to 100MHz with the absolute value of signal frequency FIN differences.The frequency of two reference electrical signals
Rate F1And F2It is unequal, F1And F2The absolute value of difference is more than or equal to 1MHz.In optical receiving end, photo-detector is also connected with feedback control
Circuit processed, feedback control circuit includes the first narrow-band filter and the second narrow-band filter, corresponding 2 moduluses
Converter and 2 logafiers, and comparator.Electric signal is recovered after opto-electronic conversion has fraction to be filtered through the first pole arrowband
Ripple device and the second narrow-band filter respectively obtain frequency for F1The first reference electrical signal and frequency be 2F1-F2Third order intermodulation
Signal, respectively after first, second A-D converter and first, second logafier, access comparator carries out Amplitude Ratio compared with obtaining
To third order intermodulation inhibiting value IM3.The output end connection electrical to optical converter of comparator, gained third order intermodulation inhibiting value optical signal warp
Another long optical fibers connect the optical-electrical converter of light transmitting terminal, recover third order intermodulation inhibiting value electric signal, access direct current biasing electricity
Volt circuit, the automatic third order intermodulation inhibiting value by current feedback finely tunes the DC offset voltage of mach zhender intensity modulator,
Mach zhender intensity modulator is locked in best operating point.
The feedback control circuit may also set up in light transmitting terminal, and the optical output port of mach zhender intensity modulator connects
Photo-coupler is connect, most soft exchange long optical fibers are transferred to the photo-detector of optical receiving end, fraction after photo-coupler light splitting
Soft exchange optical-electrical converter, the electric signal access feedback control circuit of recovery, the third order intermodulation of feedback control circuit output suppresses
Value is directly accessed DC offset voltage circuit.
The splitting ratio of the photo-coupler is (90~99)/(10~1).
The frequency F of first reference electrical signal1Or second reference electrical signal frequency F2With signal frequency FIN differences
Absolute value is more than or equal to 100MHz.
The frequency F of first reference electrical signal1With third order intermodulation signal frequency 2F1-F2Difference be more than or equal to 1MHz, select
Narrow-band filter for 3dB frequency ranges be less than or equal to 1kHz narrow-band filter, refer to telecommunications effectively to obtain first
Number F1With third order intermodulation signal 2F1-F2。
The appropriate reference electrical signal frequency F of selection1=10~12MHz and F2=11~13MHz, to reduce pole narrow-band filtering
The design difficulty and cost of device.
2 logafiers and comparator selection concurrent operation speed it is multiply-accumulate superior or equal to 10G times can
Programming device, so as to which the change of IM3 values is fed back into light echo transmitting terminal in real time.
The DC offset voltage circuit is digital adjustable reference voltage source.
Compared with prior art, a kind of direct current biasing working point control of mach zhender intensity modulator of the utility model
The advantage in loop is：1st, when the transfer function curve of mach zhender intensity modulator is influenceed to produce drift by factors such as environment
When, third order intermodulation inhibiting value will be had influence on.The third order intermodulation inhibiting value that the utility model feedback control circuit is calculated reflects light
Whole components is non-linear in Transmission system, except the maximum mach zhender intensity modulator of influence it is non-linear in addition to, also
There is the third order intermodulation inhibiting value obtained by the non-linear of the parts such as fibre circuit and optical detection, the utility model scheme to correct automatically
The DC offset voltage of mach zhender intensity modulator, locks its best operating point, the whole remote optical transport of effective compensation
The drift of the transfer function of system, is conducive to long range broadband analog signal optical transport；Using 100km distances of the present utility model
Optical transmission system receive broadband analog signal SFDR up to 90dB~100dB；2nd, the design of this loop uses normal
Component is advised, the simple cost of making is low, is suitable for popularization and application.
Brief description of the drawings
Fig. 1 is the structured flowchart of direct current biasing working point control circuit embodiments 1 of this mach zhender intensity modulator；
Fig. 2 is the structured flowchart of direct current biasing working point control circuit embodiments 2 of this mach zhender intensity modulator.
Icon code is：
1st, laser (LD), 2, mach zhender intensity modulator (MZM), 3, photodetector (PD), 4, high-pass filtering
Device (HPF), the 5, first logafier (LOG AMP), the 6, first narrow-band filter (BPF), the 7, first A-D converter
(ADC), the 8, second narrow-band filter (bpf), the 9, second A-D converter (adc), the 10, second logafier (log
Amp), 11, electrical to optical converter (E/O), 12, optical-electrical converter (O/E), 13, DC offset voltage circuit (VREF).
It is part codes used in figure in bracket.
Embodiment
Embodiment 1
The direct current biasing working point control circuit embodiments 1 of this mach zhender intensity modulator are as shown in figure 1, in light hair
End is penetrated, the tail optical fiber of laser (LD) 1 is connected to the light input end mouthful of mach zhender intensity modulator (MZM) 2, will with cable
Frequency is input to the modulation port of mach zhender intensity modulator (MZM) 2 for FIN=500MHz modulation signal, in horse
The offset port connection DC offset voltage circuit (VREF) 13 of conspicuous Zeng Deer intensity modulators (MZM) 2, is also connected with frequency point
Wei not F1=10MHz and F2=11MHz the first reference electrical signal and the second reference electrical signal.Mach zhender intensity modulator
(MZM) long optical fibers of 2 optical output port through 100km connect the photodetector (PD) 3 of optical receiving end.
Electric signal is recovered after the opto-electronic conversion of photodetector (PD) 3 of optical receiving end and is divided into two-way, through path access
High-pass filter (HPF) 4, the modulation signal for obtaining frequency FIN is output.The feedback network connection feedback of photo-detector (PD)
Circuit is controlled, feedback control circuit includes the pole arrowband of the first narrow-band filter (BPF) 6 and second that 3dB frequency ranges are 1kHz
Wave filter (bpf) 8, corresponding first, second A-D converter (ADC, adc) 7,9 and first, second logafier
(LOGAMP, logamp) 5,10, and comparator.Electric signal is recovered after opto-electronic conversion through the first narrow-band filter
(BPF) 6 and second narrow-band filter (bpf) 8 respectively obtain frequency for F1The first reference electrical signal and frequency be 2F1-F2's
Third order intermodulation signal, respectively after the first A-D converter 7, the second A-D converter 9 and first, second logafier 5,10,
Access comparator carries out Amplitude Ratio compared with obtaining third order intermodulation inhibiting value IM3.The output end connection electrical to optical converter (E/ of comparator
O) 11, gained third order intermodulation inhibiting value optical signal connects the optical-electrical converter (O/E) 12 of light transmitting terminal through another long optical fibers, extensive
Multiple third order intermodulation inhibiting value electric signal, access DC offset voltage circuit (VREF) 13, the automatic third order intermodulation for pressing current feedback
The DC offset voltage of inhibiting value fine setting mach zhender intensity modulator (MZM) 2, locks mach zhender intensity modulator
(MZM) 2 in best operating point.
Experiment shows, after the modulation signal of the light transmitting terminal transmission of this example is transmitted through long-distance optical fiber, optical receiving end institute
The broadband analog signal SFDR obtained is up to 90dB~100dB.
Embodiment 2
The direct current biasing working point control circuit embodiments 2 of this mach zhender intensity modulator are as shown in Fig. 2 100km
Optical fiber connection light transmitting terminal and optical receiving end, in light transmitting terminal, it is strong that the output optical signal of laser 1 is sent to mach zhender
The light input end mouthful of modulator (MZM) 2 is spent, modulation signal FIN is input into mach zhender intensity modulator (MZM) 2
Modulation port, in the offset port connection DC offset voltage circuit (VREF) 13 of mach zhender intensity modulator (MZM) 2,
It is also connected with frequency respectively F1And F2The first reference electrical signal and the second reference electrical signal.Mach zhender intensity modulator
(MZM) 2 optical output port connection photo-coupler, the splitting ratio of this example photo-coupler is 9/1.90% after photo-coupler light splitting
Soft exchange long optical fibers are transferred to the photo-detector (3) of optical receiving end, 10% soft exchange optical-electrical converter (O/E) 12, recovery
Electric signal accesses feedback control circuit, and feedback control circuit is same as Example 1.The third order intermodulation suppression of feedback control circuit output
Value processed is directly accessed DC offset voltage circuit 13.
Electric signal access high-pass filter (HPF) 4 is recovered after the opto-electronic conversion of photodetector (PD) 3 of optical receiving end,
The modulation signal for obtaining frequency FIN is output.
Experiment shows, after the modulation signal of the light transmitting terminal transmission of this example is transmitted through long-distance optical fiber, optical receiving end institute
The broadband analog signal SFDR obtained reaches 90dB~100dB.
Above-described embodiment, is only that the purpose of this utility model, technical scheme and beneficial effect are further described
Specific case, the utility model is not limited to this.All any modifications made within scope of disclosure of the present utility model,
Equivalent substitution, improvement etc., are all contained within protection domain of the present utility model.
Claims (10)
1. a kind of direct current biasing working point control loop of mach zhender intensity modulator, includes 100~500km long optical fibers
The light transmitting terminal and optical receiving end of connection, in light transmitting terminal, the output of laser is connected to mach zhender intensity modulator (2)
Light input end mouthful, frequency is input into mach zhender intensity modulator for FIN=300MHz~30GHz modulation signal
(2) modulation port, in the offset port connection DC offset voltage circuit (13) of mach zhender intensity modulator (2), horse
The optical output port of conspicuous Zeng Deer intensity modulators (2) connects the photodetector (3) of optical receiving end, opto-electronic conversion through long optical fibers
After recover electric signal by high-pass filter (4), obtain modulation signal and be output；It is characterized in that：
The offset port of the mach zhender intensity modulator (2) of the smooth transmitting terminal is also connected with frequency respectively F1And F2
One reference electrical signal and the second reference electrical signal, the frequency F of two reference electrical signals1、F2It is below modulation signal frequency FIN；
In optical receiving end, photo-detector (3) is also connected with feedback control circuit, and the feedback control circuit includes the first narrow-band filter
(6) and the second narrow-band filter (8), corresponding first, second A-D converter (7,9) and first, second logarithm are put
Big device (5,10), and comparator；Electric signal fraction is recovered after opto-electronic conversion through the first narrow-band filter (6) and second
Narrow-band filter (8) respectively obtains frequency for F1The first reference electrical signal and frequency be 2F1-F2Third order intermodulation signal, respectively
After first, second A-D converter (7,9) and first, second logafier (5,10), access comparator carries out Amplitude Ratio
Compared with obtaining third order intermodulation inhibiting value；The output end connection electrical to optical converter (11) of comparator, gained third order intermodulation inhibiting value light letter
The optical-electrical converter (12) of light transmitting terminal number is connected through another long optical fibers, recovers third order intermodulation inhibiting value electric signal, access is straight
Flow bias voltage circuit (13), the automatic third order intermodulation inhibiting value fine setting mach zhender intensity modulator (2) by current feedback
DC offset voltage, locking mach zhender intensity modulator (2) in best operating point.
2. the direct current biasing working point control loop of mach zhender intensity modulator according to claim 1, its feature
It is：
The feedback control circuit is arranged at light transmitting terminal, the optical output port connection light of mach zhender intensity modulator (2)
Coupler, most soft exchange long optical fibers are transferred to the photo-detector of optical receiving end after photo-coupler light splitting, and fraction light connects
Enter optical-electrical converter (12), the electric signal access feedback control circuit of recovery, the third order intermodulation of feedback control circuit output suppresses
Value is directly accessed DC offset voltage circuit (13).
3. the direct current biasing working point control loop of mach zhender intensity modulator according to claim 2, its feature
It is：
The splitting ratio of the photo-coupler is (90~99)/(10~1).
4. the direct current biasing working point control of mach zhender intensity modulator according to any one of claim 1 to 3
Loop, it is characterised in that：
The frequency F of first reference electrical signal1Or second reference electrical signal frequency F2Less than modulation signal frequency FIN, and
It is more than or equal to 100MHz with the absolute value of signal frequency FIN differences.
5. the direct current biasing working point control loop of mach zhender intensity modulator according to claim 4, its feature
It is：
The frequency F of described two reference electrical signals1And F2It is unequal, F1And F2The absolute value of difference is more than or equal to 1MHz.
6. the direct current biasing working point control loop of mach zhender intensity modulator according to claim 5, its feature
It is：
The first reference electrical signal frequency F1=10~12MHz, the second reference electrical signal frequency F2=11~13MHz.
7. the direct current biasing working point control of mach zhender intensity modulator according to any one of claim 1 to 3
Loop, it is characterised in that：
The first reference electrical signal F1With third order intermodulation signal 2F1-F2Frequency values difference be more than or equal to 1MHz.
8. the direct current biasing working point control loop of mach zhender intensity modulator according to claim 7, its feature
It is：
The narrow-band filter is the narrow-band filter that 3dB frequency ranges are less than or equal to 1kHz.
9. the direct current biasing working point control of mach zhender intensity modulator according to any one of claim 1 to 3
Loop, it is characterised in that：
2 logafiers and comparator are the concurrent operation speed Programmable multiply-accumulate superior or equal to 10G times
Part.
10. the direct current biasing working point control of mach zhender intensity modulator according to any one of claim 1 to 3
Loop, it is characterised in that：
The DC offset voltage circuit is digital adjustable reference voltage source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621467944.0U CN206610038U (en) | 2016-12-29 | 2016-12-29 | A kind of direct current biasing working point control loop of mach zhender intensity modulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621467944.0U CN206610038U (en) | 2016-12-29 | 2016-12-29 | A kind of direct current biasing working point control loop of mach zhender intensity modulator |
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| Publication Number | Publication Date |
|---|---|
| CN206610038U true CN206610038U (en) | 2017-11-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621467944.0U Withdrawn - After Issue CN206610038U (en) | 2016-12-29 | 2016-12-29 | A kind of direct current biasing working point control loop of mach zhender intensity modulator |
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| CN (1) | CN206610038U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106646932A (en) * | 2016-12-29 | 2017-05-10 | 中国电子科技集团公司第三十四研究所 | DC bias operating point control loop of Maher Zeng Del intensity modulator |
| CN114584223A (en) * | 2022-03-15 | 2022-06-03 | 中山大学 | Pulse width modulation system and method for Mach-Zehnder interferometer |
-
2016
- 2016-12-29 CN CN201621467944.0U patent/CN206610038U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106646932A (en) * | 2016-12-29 | 2017-05-10 | 中国电子科技集团公司第三十四研究所 | DC bias operating point control loop of Maher Zeng Del intensity modulator |
| CN114584223A (en) * | 2022-03-15 | 2022-06-03 | 中山大学 | Pulse width modulation system and method for Mach-Zehnder interferometer |
| CN114584223B (en) * | 2022-03-15 | 2023-07-21 | 中山大学 | Pulse width modulation system and method for Mach-Zehnder interferometer |
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Granted publication date: 20171103 Effective date of abandoning: 20230523 |
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Granted publication date: 20171103 Effective date of abandoning: 20230523 |