CN101350674B - Phase adjustment method and device and optical modulator - Google Patents
Phase adjustment method and device and optical modulator Download PDFInfo
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- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
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Abstract
The invention discloses a phase adjustment method, a phase adjustment device and an optical modulator. The method of the invention comprises the following steps: obtaining a response signal with a low-frequency disturbance signal, and obtaining a response signal of the frequency of the low-frequency disturbance signal through the response signal; dividing a standard clock period with a preset length into two equal time slots, and sampling the response signal in the time slots through a sampling clock; acquiring sampling values of the response signals in the two divided time slots; obtaining a characterization value by using all sampling values in each time slot, and obtaining a characterization difference value between the two characterization values; and obtaining an adjustment difference value between the characterization difference value and a preset threshold value, and moving the phase of the low-frequency disturbance signal by a corresponding angle according to the adjustment difference value. The phase difference between the low frequency perturbation signal and the response signal is kept constant. The invention also discloses a phase adjusting device and an optical modulator.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for adjusting a phase, and an optical modulator.
Background
With the continuous and deep research of optical and electronic communication, optical communication is rapidly developed. The distance over which electrical relay transmission is not carried over in optical transmission systems has reached hundreds of kilometres. When the optical fiber is transmitted, the external modulator is adopted to enable the laser to work in a continuous wave mode, and the influence of frequency chirp is simply and thoroughly overcome. In addition, it can provide higher speed, higher extinction ratio and greater power. Therefore, the external modulation technology is an ideal choice for ultra-high speed, long-distance optical transmission.
Most of the current optical modulators are mach-zehnder modulators, and among them, lithium niobate (LiNbio3) modulators are mainly used. The operation of the lithium niobate modulator is described below.
The working principle of the lithium niobate modulator utilizes the characteristic that the refractive index of a special material can change along with the change of an external electric field to realize the modulation function. An external electric field causes the change of the refractive index of the material, the change of the refractive index causes the phase change of the carried modulated optical signal, and the phase change of the optical signal is combined with a specific Mach (MZ) interferometer to generate an interference effect on an output signal, so that the modulation of the optical intensity, namely the modulation of the optical power is realized.
The operating characteristic curve of the lithium niobate modulator is shown in fig. 1, and the V coordinate represents the applied direct current Bias (Bias) voltage of the modulator. Different applied dc bias voltages correspond to different output optical powers. The Bias voltage can be operated at various voltage points to achieve output optical power up to MAX (MAX), MIN (MIN), two Quad points (i.e., Quad-, Quad +) and other optical power points. During the operation of the modulator, when the light source is modulated by a high-speed non-return-to-zero (NRZ) code electric signal, the modulator works at two Quad points, the error rate is lowest for a digital signal system, and the distortion is lowest for an analog system. Therefore, the voltage value of the applied DC bias voltage is stabilized at Vpi/2 to ensure that the optical power is stabilized at the Quad point, and the output optical modulation signal is optimal. However, in practical situations, the Bias voltage of the lithium niobate modulator may drift due to temperature (i.e., the dc voltage varies with temperature), i.e., the input voltage Vin (Bias voltage) may vary. Therefore, it is necessary to continuously compensate for the drift of the dc Bias voltage, so that the output value of the optical power is locked at the Quad point. The Bias control of Bias voltage in the prior art mainly adopts the following two ways.
The first mode is amplitude modulation Bias control, and the principle of the amplitude modulation Bias control is that high-frequency data signals (RF) are used for amplitude modulation, and Bias voltage control is realized by calculating the feedback value of a feedback signal of a modulator. Referring to fig. 2, a low-frequency disturbing signal (a periodic sinusoidal signal) is loaded on an amplitude modulation end of an amplitude driver to realize amplitude modulation of RF. The modulated signal, i.e., the PD response signal, is extracted by a backlight detection Photodiode (PD). And amplifying the PD response signal, and performing frequency-selective filtering in the frequency range of the low-frequency disturbance signal to obtain the PD response signal existing in the low-frequency disturbance frequency.
When the low-frequency disturbance signal is positive disturbance or negative disturbance, the maximum and minimum values of the positive disturbance amplitude and the negative disturbance amplitude can be synchronously demodulated and calculated through the bias control module, and the amplitude difference (Vpp) is obtained. When Vpp is smaller and close to zero, the Bias voltage of the modulator is indicated to work at +/-Vpi/2, namely the optical power works at +/-Quad point; when Vpp is larger, it indicates that the Bias voltage of the modulator is operating off Vpi/2, i.e., the optical power has deviated from the point of ± Quad. The compensation value required by the Bias voltage can be obtained through the size of the Vpp, so that the Bias voltage compensation is realized.
The second way of adding the low frequency perturbation signal is different from the first way, and is not added through the amplitude modulation pin of the driver, but is added through the Bias terminal of the modulator. And judging the offset of the Bias voltage by calculating the Vpp of the PD response signal of the low-frequency disturbance signal at the disturbance frequency of the low-frequency disturbance signal and the Vpp of the output signal at the low-frequency second harmonic frequency, thereby obtaining a compensation value of the Bias voltage.
In the process of calculating the Bias voltage compensation value, only when the phase difference between the PD response signal and the low-frequency disturbance signal is synchronous, the Vpp can be accurately calculated, thereby realizing the compensation of the Bias voltage. In order to enable the PD response signal obtained from the modulator to obtain an amplitude signal meeting the calculation of the Vpp when the signal-to-noise ratio is very low, the two modes both adopt a multi-stage filtering and multi-stage amplifying circuit, and because the multi-stage filtering and the multi-stage amplifying circuit have different phase changes at different temperatures, the PD response signal and the low-frequency disturbance signal are asynchronous and have phase differences, so that the deviation of the calculation of the Vpp is caused, and the control precision of the Bias voltage is reduced; if part of the amplifying circuit and the filter circuit is removed to reduce the phase difference, the PD signal will be degraded. Therefore, the problem of phase difference between the PD response signal and the low-frequency disturbance signal always plagues the control accuracy of the Bias voltage.
Disclosure of Invention
An embodiment of the present invention provides a method for adjusting a phase, including:
obtaining a response signal with a low-frequency disturbance signal, and obtaining a response signal of the frequency of the low-frequency disturbance signal through the response signal;
dividing a standard clock period with a preset length into two equal time slots, and sampling the response signal in the time slots through a sampling clock; when the response signal is synchronous with the standard clock, the waveforms of the response signals in the two time slots are symmetrical;
acquiring sampling values of the response signals in the two divided time slots;
obtaining a characterization value by using all sampling values in each time slot, and obtaining a characterization difference value between the two characterization values;
and obtaining an adjustment difference value between the characterization difference value and a preset threshold value, and moving the phase of the low-frequency disturbance signal by a corresponding angle according to the adjustment difference value.
An embodiment of the present invention provides a phase adjustment apparatus, including:
the signal extraction unit is used for obtaining a response signal with a low-frequency disturbance signal and obtaining a response signal of the frequency of the low-frequency disturbance signal through the response signal;
a standard clock unit for dividing a standard clock cycle of a predetermined length into two equal time slots and providing a standard clock signal; when the response signal is synchronous with the standard clock, the waveforms of the response signals in the two time slots are symmetrical;
a sampling unit, configured to sample the response signal by a sampling clock in the time slot; acquiring sampling values of the response signals in the two divided time slots;
the computing unit is used for obtaining the representation values by utilizing all sampling values in each time slot, obtaining the representation difference value between the two representation values and obtaining the adjustment difference value between the representation difference value and the preset threshold value;
the judging unit is used for judging whether the adjustment difference value exceeds a preset threshold value or not and obtaining a judging result;
and the adjusting unit is used for moving the phase of the low-frequency disturbance signal by a corresponding angle according to the judgment result and the adjustment difference value.
An embodiment of the present invention provides an optical modulator including:
input means for inputting the low frequency perturbation signal and the RF signal into the optical modulator;
the photoelectric conversion device is used for obtaining the modulated optical response signal with the low-frequency disturbance signal and converting the optical response signal into a response signal;
a phase adjustment device comprising:
the signal extraction unit is used for obtaining a response signal with a low-frequency disturbance signal from the photoelectric conversion device and obtaining a response signal with a low-frequency disturbance signal frequency through the response signal;
a standard clock unit for dividing a standard clock cycle of a predetermined length into two equal time slots and providing a standard clock signal; when the response signal is synchronous with the standard clock, the waveforms of the response signals in the two time slots are symmetrical;
a sampling unit, configured to sample the response signal by a sampling clock in the time slot; acquiring sampling values of the response signals in the two divided time slots;
the computing unit is used for obtaining the representation values by utilizing all sampling values in each time slot, obtaining the representation difference value between the two representation values and obtaining the adjustment difference value between the representation difference value and the preset threshold value;
the judging unit is used for judging whether the adjustment difference value exceeds a preset threshold value or not and obtaining a judging result;
the adjusting unit is used for shifting the phase of the low-frequency disturbance signal by a corresponding angle according to the judgment result and the adjusting difference value;
and the bias voltage control device is used for calculating through the low-frequency disturbance signal and the response signal and increasing or decreasing the bias voltage by using a calculation result.
The method and the device in the embodiment of the invention can adjust the phase difference between the low-frequency disturbing signal and the response signal, so that the phase difference between the low-frequency disturbing signal and the response signal is kept constant, the phase difference is not influenced by temperature and devices, and the cost of hardware design is reduced. The optical modulator in the embodiment of the invention can calculate through the low-frequency disturbance signal and the response signal, and improve or reduce the bias voltage by using the calculation result, thereby improving the reliability of locking the bias voltage. The bias voltage and the power of the optical modulator are enabled to work at a stable working point, and therefore a stable optical modulation signal is output.
Drawings
FIG. 1 is a schematic diagram of the characteristics of the operation of a lithium niobate modulator;
FIG. 2 is a schematic diagram of a lithium niobate modulator;
FIG. 3 is a block diagram of a modulator according to a first embodiment of the present invention;
FIG. 4 is a flow chart of a first embodiment of the present invention;
FIG. 5 is a waveform diagram illustrating synchronization between a standard signal and a response signal according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating a response signal waveform deviating from a standard signal waveform to the left according to an embodiment of the present invention;
FIG. 7 is a diagram illustrating a response signal waveform deviating from a standard signal waveform to the right according to an embodiment of the present invention;
FIG. 8 is a block diagram of an apparatus according to a second embodiment of the present invention;
fig. 9 is a structural diagram of an optical modulator according to a third embodiment of the present invention.
Detailed Description
The following describes a specific implementation scheme for adjusting the phase difference between the response signal and the low-frequency disturbance signal in detail through an embodiment of the present invention. First, referring to fig. 3, a first embodiment of the present invention is described in detail with reference to fig. 3 and 4, in which the modulator is an MZ-type modulator, which may be a lithium niobate modulator. In the modulator, photoelectric conversion is carried out through a PD end to obtain an electric signal, AD sampling is carried out after filtering and amplification, a digital processing chip utilizes a sampling value for judgment, and a judged result is utilized to adjust a low-frequency disturbing signal. The specific implementation process is shown in fig. 4, and includes the following steps:
step 401: obtaining a response signal with a low-frequency disturbance signal, and obtaining a response signal of the frequency of the low-frequency disturbance signal through the response signal;
and obtaining an optical response signal through the PD end of the modulator, carrying out photoelectric conversion on the optical response signal to obtain a response signal, and filtering the obtained response signal, wherein the filtering comprises frequency selection and band pass, and the response signal only with low-frequency disturbance signal frequency is filtered.
After the PD response signal is obtained, the following AD sampling process will be performed. The frequencies of the standard clock and the sampling clock may be varied during sampling, and in this embodiment, the standard clock is 1K and the sampling clock is 20K. I.e. 20 samples can be taken within one period of the standard clock signal.
Step 402: dividing a standard clock period with a preset length into two equal time slots, and sampling a response signal in the time slots;
the predetermined length used may be one-half, or three-quarters of one standard clock cycle, or multiple standard clock cycles, etc. When the response signal is sampled in the standard clock period with the predetermined length, the standard clock period with the predetermined length needs to be divided into two equal time slots, and the two divided time slots are not continuous. However, the two time slots are such that when the response signal is synchronized with the standard clock, the waveforms of the response signals in the two time slots are symmetrical, and may be mirror symmetry or origin symmetry.
For convenience of illustration, in the present embodiment, the standard clock cycle length is one-half of the standard clock cycle length, and the standard clock cycle length is divided into two consecutive and equal time slots. The waveform schematic diagram of sampling the response signal in the time slot divided by the standard clock period can be seen in fig. 5, fig. 5 is the waveform schematic diagram when the standard clock and the response signal are synchronous, the square waveform in the figure is the waveform of the standard clock signal, each square wave is the signal time slot of the standard clock period, and the curve waveform is the waveform of the response signal. In sampling, the response signal is sampled in the positive direction (i.e., the upper half axis in fig. 5) and the negative direction (i.e., the lower half axis in fig. 5) in the time slot of the square wave. In a square wave time slot, 10 times of sampling values are obtained, and the sampling values in two time slots are counted respectively.
Step 403: recording the obtained sampling values in an array;
step 404: judging whether the sampling times are less than the maximum sampling times;
in this embodiment, after each sampling, it is determined whether the current sampling frequency is less than the maximum sampling frequency, that is, whether the current sampling frequency is not equal to 10, and if not, the step 402 is continuously executed until the sampling 10 times is finished; if the number of sampling times is greater than 10, the sampling operation is not performed, and step 405 is performed.
Step 405: and respectively calculating the characteristic values of the response signal sampling results in the two time slots.
When the standard signal and the response signal are out of synchronization, a waveform deviation as shown in fig. 6 or fig. 7 may occur. In fig. 6, the waveform of the response signal is shifted to the left in the square-wave time slot of the standard clock, and during sampling, a reverse sampling value of the response signal is collected in the negative direction, and a sampling value in the same direction as the standard clock is collected in the positive direction; in fig. 7, the waveform of the response signal is shifted to the right in the square wave slot of the standard clock, and a sampling result similar to that of fig. 6 also appears when sampling.
And respectively calculating the characteristic values of the response signal sampling results in the two divided time slots, wherein the calculation process is to perform any one of sum, difference, product, logarithm and integral or the combination of the sum, the difference, the product, the logarithm and the integral on all sampling values in each time slot. Preferably, the sampled values are summed to obtain the representative value of each time slot.
In this embodiment, taking the waveform diagram of fig. 6 as an example, as the response signal shifts to the left, a forward sampling value 5 times can be obtained in the time slot on the left side of the square wave, and a characterization value obtained by performing a sum operation on the sampling values is denoted as SUMA; for the time slot with shading on the right side, 5 negative sampling values can be obtained, and since the response signal is in the negative direction, the characterization value obtained after the obtained sampling values are subjected to the sum operation is recorded as SUMB, and is a negative value.
Step 406: judging whether the characterization difference value between the two characterization values is greater than a preset threshold value, if so, executing step 407; if so, go to step 408;
wherein the predetermined threshold value is a characteristic difference value obtained in accordance with the divided time slot when the response signal is synchronized with the standard clock. The preset threshold value is related to the waveform of the response signal in the divided time slot, if the waveform of the divided response signal is bilaterally symmetrical when the time slot is divided, the representation difference value obtained by subtracting the two time slots is adopted, namely the threshold value is 0; if the waveform of the divided response signal is symmetrical with the origin when the time slot is divided, the characterization difference obtained by subtracting the two time slots is not 0.
In this embodiment, the divided two slots are equal, the sampling times of each slot are the same, and the waveforms of the response signals in the two slots belong to mirror symmetry, so that the predetermined threshold is 0. For the determination process, taking fig. 6 as an example, the response signal is just in the time slot on the left side of the standard clock, at this time, the value of SUMB is a negative value, the result of subtracting SUMB from SUMA is denoted as SUMC, and the result of subtracting a negative value from a positive value is necessarily a positive value greater than the threshold 0, which indicates that the phase of the low frequency disturbance signal is shifted to the right with respect to the phase of the standard clock.
Step 407: the phase of the low-frequency disturbance clock is shifted to the left by corresponding degrees;
when the phase of the low-frequency disturbance clock is adjusted to the left, an adjustment difference between the characterization difference and a predetermined threshold needs to be obtained, and the corresponding degree is moved by the adjustment difference.
In the present embodiment, if the phase difference of the obtained adjustment difference SUMC corresponding to the response signal of the left portion of the standard clock signal is 45 degrees, the phase of the low-frequency disturbance signal is shifted to the left by 45 degrees, and the degree of the phase is reduced by 45 degrees.
Step 408: judging whether the characterization difference value between the two characterization values is smaller than a preset threshold value, and if so, executing a step 409; otherwise, it indicates that no phase shift occurs, and ends the adjustment or re-executes step 401.
Taking fig. 7 as an example, if the condition of being smaller than the threshold occurs, the waveform diagram shown in fig. 7 occurs, and at this time, the response signal in the standard clock waveform (i.e., square wave) is negative in the unshaded region, so the sampling result SUMA is recorded as a negative value, the sampling result of the response signal in the shaded region is recorded as SUMB, and the SUMB is obtained as a positive value. SUMA minus SUMB must result in SUMC being less than the negative of threshold 0.
Step 409: the phase of the low frequency perturbation clock is shifted to the right by a corresponding number of degrees.
When the phase of the low-frequency disturbance clock is adjusted to the right, an adjustment difference between the characterization difference and a predetermined threshold needs to be obtained, and the corresponding degree is moved by the adjustment difference.
In this embodiment, the corresponding phase degree may be obtained according to the obtained difference SUMC, and the phase of the low-frequency perturbation signal is increased by the corresponding degree, so that the waveform of the low-frequency perturbation signal is shifted to the right.
By this point, the phase adjustment process in this embodiment ends.
The above embodiment explains the process of adjusting the phase difference in detail, and an embodiment of a second embodiment, i.e., an embodiment of an apparatus for realizing the above phase difference adjusting process, is given below, referring to fig. 8, in which the phase difference adjusting apparatus includes: a signal extraction unit 801, a standard clock unit 802, a sampling unit 803, an arithmetic unit 804, a judgment unit 805, an adjustment unit 806,
a signal extraction unit 801, configured to obtain a response signal with a low-frequency disturbance signal, and obtain a response signal of a low-frequency disturbance signal frequency through the response signal;
a standard clock unit 802 for dividing a standard clock cycle of a predetermined length into two equal time slots and providing a standard clock signal; when the response signal is synchronous with the standard clock, the waveforms of the response signals in the two time slots are symmetrical;
a sampling unit 803, configured to sample the response signal by a sampling clock within the time slot; acquiring sampling values of the response signals in the two divided time slots;
an operation unit 804, configured to obtain a characterization value by using all sampling values in each time slot, obtain a characterization difference between two characterization values, and obtain an adjustment difference between the characterization difference and a predetermined threshold;
a determining unit 805, configured to determine whether the adjustment difference exceeds a predetermined threshold, and obtain a determination result;
and an adjusting unit 806, which shifts the phase of the low-frequency disturbance signal by a corresponding angle according to the determination result and the adjustment difference.
The process of obtaining the characterization value by the operation unit 804 using all the sampling values in each time slot includes:
and performing any one of sum, difference, product, logarithm and integral or combination operation on all sampling values in each time slot to obtain a characterization value.
Wherein the adjusting unit 806 includes:
a first adjusting unit 807, configured to reduce the phase of the low-frequency perturbation signal by a corresponding angle according to the difference when the determination result is that the difference is greater than the predetermined threshold;
and a second adjusting unit 808, configured to increase the phase of the low-frequency perturbation signal by a corresponding angle according to the difference when the determination result is that the adjustment difference is smaller than the threshold.
The method and the device in the embodiment of the invention can adjust the phase difference between the low-frequency disturbing signal and the response signal, so that the phase difference between the low-frequency disturbing signal and the response signal keeps synchronous. The characteristic value can be obtained through various modes, the calculation mode is flexible and easy to realize, and the control precision of the phase difference is accurate.
The phase difference control device can be used in various electronic devices, such as an optical modulator, but is not limited to the optical modulator. The third embodiment of the invention is given below when the device is applied to an optical modulator.
Referring to fig. 9, fig. 9 is a structural diagram of an optical modulator, and the optical modulator of this embodiment includes an input device 901, a bias voltage control device 902, a phase adjustment device 903, and a photoelectric conversion device 904, where the optical modulator may be an MZ modulator.
An input means 901 for inputting the low frequency perturbation signal and the RF signal into the optical modulator;
a photoelectric conversion device 904, configured to obtain a modulated optical response signal with a low-frequency disturbance signal, and convert the optical response signal into a response signal;
the phase adjustment device 903 includes: a signal extraction unit 905, a standard clock unit 906, a sampling unit 907, an operation unit 908, a judgment unit 909, and an adjustment unit 910;
a signal extraction unit 905, configured to obtain a response signal with a low-frequency disturbance signal from the photoelectric conversion apparatus 904, and obtain a response signal with a low-frequency disturbance signal frequency according to the response signal;
a standard clock unit 906 for dividing a standard clock cycle of a predetermined length into two equal time slots and providing a standard clock signal; when the response signal is synchronous with the standard clock, the waveforms of the response signals in the two time slots are symmetrical;
a sampling unit 907 for sampling the response signal by a sampling clock within the time slot; acquiring sampling values of the response signals in the two divided time slots;
an operation unit 908, configured to obtain a token value by using all sample values in each time slot, obtain a token difference between two token values, and obtain an adjustment difference between the token difference and a predetermined threshold;
a judging unit 909 for judging whether the adjustment difference exceeds a predetermined threshold and obtaining a judgment result;
an adjusting unit 910, configured to shift the phase of the low-frequency perturbation signal by a corresponding angle according to the determination result and the adjustment difference;
and a bias voltage control device 902, configured to perform calculation according to the low-frequency disturbance signal and the response signal, and increase or decrease the bias voltage according to a calculation result.
Wherein the adjusting unit 910 includes:
a first adjusting unit 911, configured to reduce the phase of the low-frequency perturbation signal by a corresponding angle according to the difference when the determination result is that the adjustment difference is greater than the predetermined threshold;
a second adjusting unit 912, configured to increase the phase of the low-frequency perturbation signal by a corresponding angle according to the difference value when the determination result is that the adjustment difference value is smaller than the predetermined threshold value.
In this embodiment, the phase difference may be adjusted without interruption; a control switch may be further added to perform an operation of adjusting the phase difference when the bias voltage is unstable.
The optical modulator in the embodiment of the invention can calculate the low-frequency disturbance signal and the response signal, and the bias voltage is increased or reduced by using the calculation result, so that the bias voltage and the power of the optical modulator work at a stable working point, and the stable optical modulation signal is output.
For those skilled in the art, the calculation process of the bias voltage control device can be implemented in various existing manners, such as calculating the deviation value of the bias voltage according to the amplitude relationship of the low-frequency disturbance signal and the response signal; there is also a technique of calculating a deviation value of the bias voltage by controlling the bias voltage to operate at MAX or MIN as shown in fig. 1 to perform a corresponding adjustment. All the technologies can carry out phase control through the scheme in the embodiment of the invention so as to realize more stable control on the bias voltage.
Any modification, equivalent replacement, improvement, etc. made to the method, device and light modulator set forth in the various embodiments of the present invention shall be included in the protection scope of the present invention within the spirit and principle of the present invention.
Claims (10)
1. A method of phase adjustment, comprising:
obtaining a response signal with a low-frequency disturbance signal, filtering the obtained response signal with the low-frequency disturbance signal, and filtering out the response signal with only the low-frequency disturbance signal;
dividing a standard clock period with a preset length into two equal time slots, and sampling the response signal only with the low-frequency disturbance signal in the time slots through a sampling clock; when the response signal only with the low-frequency disturbing signal is synchronous with the standard clock, the response signal only with the low-frequency disturbing signal in the two time slots has symmetrical waveform;
in the two divided time slots, acquiring the sampling value of the response signal only with the low-frequency disturbance signal;
obtaining a characterization value by using all sampling values in each time slot, and obtaining a characterization difference value between the two characterization values;
and obtaining an adjustment difference value between the characterization difference value and a preset threshold value, and moving the phase of the low-frequency disturbance signal by a corresponding angle according to the adjustment difference value.
2. The method of claim 1, wherein obtaining the characterization value using all sample values in each time slot comprises:
and performing any one of sum, difference, product, logarithm and integral or combination operation on all sampling values in each time slot to obtain a characterization value.
3. The method of claim 1, wherein the step of shifting the phase of the low frequency perturbation signal by a corresponding angle according to the adjustment difference comprises:
when the characterization difference is larger than the threshold, reducing the phase of the low-frequency disturbance signal by a corresponding angle according to the adjustment difference;
and when the characterization difference is smaller than the threshold, increasing the phase of the low-frequency disturbance signal by a corresponding angle according to the adjustment difference.
4. The method according to claim 1, wherein the predetermined threshold is a characteristic difference obtained according to divided time slots when the response signal only having the low-frequency disturbance signal is synchronized with the standard clock.
5. An apparatus for phase adjustment, comprising:
the signal extraction unit is used for obtaining a response signal with a low-frequency disturbance signal, filtering the obtained response signal with the low-frequency disturbance signal and filtering out a response signal with only the low-frequency disturbance signal;
a standard clock unit for dividing a standard clock cycle of a predetermined length into two equal time slots and providing a standard clock signal; when the response signal only with the low-frequency disturbing signal is synchronous with the standard clock, the response signal only with the low-frequency disturbing signal in the two time slots has symmetrical waveform;
the sampling unit is used for sampling the response signal only with the low-frequency disturbance signal in the time slot through a sampling clock; in the two divided time slots, acquiring the sampling value of the response signal only with the low-frequency disturbance signal;
the computing unit is used for obtaining the representation values by utilizing all sampling values in each time slot, obtaining the representation difference value between the two representation values and obtaining the adjustment difference value between the representation difference value and the preset threshold value;
the judging unit is used for judging whether the adjustment difference value exceeds a preset threshold value or not and obtaining a judging result;
and the adjusting unit is used for moving the phase of the low-frequency disturbance signal by a corresponding angle according to the judgment result and the adjustment difference value.
6. The apparatus of claim 5, wherein the operation unit obtains the characterization value by using all the sampling values in each time slot, and comprises:
and performing any one of sum, difference, product, logarithm and integral or combination operation on all sampling values in each time slot to obtain a characterization value.
7. The apparatus of claim 5, wherein the adjusting unit comprises:
a first adjusting unit, configured to reduce the phase of the low-frequency perturbation signal by a corresponding angle according to the difference when the determination result is that the adjustment difference is greater than the predetermined threshold;
and the second adjusting unit is used for increasing the phase of the low-frequency disturbing signal by a corresponding angle according to the difference when the judgment result shows that the adjusting difference is smaller than the preset threshold.
8. An optical modulator, comprising: an input device, a photoelectric conversion device, a bias voltage control device and a phase adjustment device; wherein,
input means for inputting the low frequency perturbation signal and the high frequency data RF signal into the optical modulator;
the photoelectric conversion device is used for obtaining the modulated optical response signal with the low-frequency disturbance signal and converting the optical response signal into an electric response signal;
the bias voltage control device is used for calculating through the low-frequency disturbance signal and the electric response signal and increasing or decreasing the bias voltage by using a calculation result;
a phase adjustment device comprising: the device comprises a signal extraction unit, a standard clock unit, a sampling unit, an arithmetic unit, a judgment unit and an adjustment unit; wherein,
the signal extraction unit is used for obtaining a response signal with a low-frequency disturbance signal from the photoelectric conversion device, filtering the obtained response signal with the low-frequency disturbance signal and filtering out the response signal with only the low-frequency disturbance signal;
a standard clock unit for dividing a standard clock cycle of a predetermined length into two equal time slots and providing a standard clock signal; when the response signal only with the low-frequency disturbing signal is synchronous with the standard clock, the response signal only with the low-frequency disturbing signal in the two time slots has symmetrical waveform;
the sampling unit is used for sampling the response signal only with the low-frequency disturbance signal in the time slot through a sampling clock; in the two divided time slots, acquiring the sampling value of the response signal only with the low-frequency disturbance signal;
the computing unit is used for obtaining the representation values by utilizing all sampling values in each time slot, obtaining the representation difference value between the two representation values and obtaining the adjustment difference value between the representation difference value and the preset threshold value;
the judging unit is used for judging whether the adjustment difference value exceeds a preset threshold value or not and obtaining a judging result;
and the adjusting unit is used for moving the phase of the low-frequency disturbance signal by a corresponding angle according to the judgment result and the adjustment difference value.
9. The optical modulator according to claim 8, wherein the adjusting unit comprises:
a first adjusting unit, configured to reduce the phase of the low-frequency perturbation signal by a corresponding angle according to the difference when the determination result is that the adjustment difference is greater than the predetermined threshold;
and the second adjusting unit is used for increasing the phase of the low-frequency disturbing signal by a corresponding angle according to the difference when the judgment result shows that the adjusting difference is smaller than the preset threshold.
10. The optical modulator of claim 8, wherein the optical modulator is a mach-zehnder modulator.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200710135834 CN101350674B (en) | 2007-07-16 | 2007-07-16 | Phase adjustment method and device and optical modulator |
| PCT/CN2008/071642 WO2009010007A1 (en) | 2007-07-16 | 2008-07-15 | A method, an apparatus and an optical modulator for phase adjustment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 200710135834 CN101350674B (en) | 2007-07-16 | 2007-07-16 | Phase adjustment method and device and optical modulator |
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| CN101350674B true CN101350674B (en) | 2012-04-04 |
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| CN101794001B (en) * | 2010-01-22 | 2012-04-04 | 苏州旭创科技有限公司 | Design method of novel radio frequency simulation SFP module |
| CN101808063B (en) * | 2010-03-30 | 2014-01-01 | 中兴通讯股份有限公司 | Method and device for controlling modulator phase delay bias point |
| CN102834770A (en) * | 2011-04-14 | 2012-12-19 | 华为技术有限公司 | Optical modulation method and system |
| CN108345554B (en) * | 2017-01-22 | 2020-08-21 | 联发科技股份有限公司 | Method for determining sampling phase of sampling clock signal and related electronic device |
| CN109257103A (en) * | 2018-09-30 | 2019-01-22 | 武汉联特科技有限公司 | A kind of control method and system of M-Z modulator stabilization of operating point |
| CN112887010B (en) * | 2021-01-22 | 2022-07-19 | 中国人民解放军国防科技大学 | An inter-satellite link signal level cooperative communication method, device and computer equipment |
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| CN1254851A (en) * | 1998-11-25 | 2000-05-31 | 富士通株式会社 | Optical modulation apparatus and method of controlling optical modulator |
| CN2517183Y (en) * | 2001-11-27 | 2002-10-16 | 华为技术有限公司 | Optical signal modulation device of optical communication system |
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| JP3730789B2 (en) * | 1998-10-20 | 2006-01-05 | 日本放送協会 | Light modulator |
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| CN1254851A (en) * | 1998-11-25 | 2000-05-31 | 富士通株式会社 | Optical modulation apparatus and method of controlling optical modulator |
| CN2517183Y (en) * | 2001-11-27 | 2002-10-16 | 华为技术有限公司 | Optical signal modulation device of optical communication system |
| CN1253756C (en) * | 2002-04-05 | 2006-04-26 | 株式会社东芝 | Light modulator, light signal transmitting apparatus and method for controlling light modulator |
| EP1696570A2 (en) * | 2002-07-30 | 2006-08-30 | Sanyo Denki Co., Ltd. | Synchronised sinusoidal signal controller |
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