CN111988135B - Time domain calibration device and method for optical pulse and electric pulse - Google Patents
Time domain calibration device and method for optical pulse and electric pulse Download PDFInfo
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- CN111988135B CN111988135B CN201910423263.6A CN201910423263A CN111988135B CN 111988135 B CN111988135 B CN 111988135B CN 201910423263 A CN201910423263 A CN 201910423263A CN 111988135 B CN111988135 B CN 111988135B
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Abstract
The invention discloses a time domain calibration device and a time domain calibration method for optical pulses and electric pulses, wherein the technical scheme of the invention can automatically issue a plurality of different delay values through an upper computer, draw a curve of optical pulse power output by an intensity modulation device and the issued delay values under different delay values, obtain a target delay value based on the curve, and further delay one of two electric trigger signals corresponding to shorter path time based on the target delay value. Therefore, the technical scheme of the invention can realize the automatic alignment of the optical pulse and the electric pulse in the phase modulator in the quantum key distribution system, and has the advantages of simple operation, small workload and high efficiency.
Description
Technical Field
The invention relates to the technical field of quantum communication, in particular to a time domain calibration device and method for optical pulses and electric pulses.
Background
Quantum communication is a strategic top-end technology, and has important application value and prospect in the fields of national security, military, finance, energy and the like, and a quantum key distribution technology is a key technology of quantum communication.
The quantum key distribution technology based on the decoy state protocol has also been widely accepted for the safety of reality. At present, quantum key distribution becomes a mature subject and is from a laboratory stage to an engineering application stage.
In a quantum key distribution system, intensity modulation of signal light pulses is required. In the prior art, when intensity modulation is performed on signal light pulses, a delay value needs to be manually set so as to align the light pulses and the electric pulses on a phase modulator, and the method has the disadvantages of complex operation, large workload and low efficiency.
Disclosure of Invention
In view of this, the technical solution of the present invention provides a time domain calibration apparatus and method for optical pulses and electrical pulses, which can achieve automatic alignment of the optical pulses and the electrical pulses in a phase modulator, and have the advantages of simple operation, small workload, and high efficiency.
In order to achieve the above purpose, the invention provides the following technical scheme:
a time domain calibration device of optical pulse and electric pulse is used for an intensity modulation device, wherein the intensity modulation device is used for carrying out intensity modulation on incident optical pulse, dividing the optical pulse into two optical pulse components, loading pulse voltage on one optical pulse component, modulating the two optical pulse components to form a phase difference, and then outputting a synthesized optical pulse of the two optical pulse components;
the time domain calibration device comprises: the device comprises an upper computer, a control circuit, a laser driving chip and a pulse voltage generating chip;
the upper computer is used for configuring the driving parameters of the laser for the laser driving chip through the control circuit and configuring pulse voltage parameters for the pulse voltage generating chip; the laser is used for emitting the optical pulse;
the control circuit is used for acquiring a delay value issued by the upper computer and generating two electric trigger signals based on the delay value; one electrical trigger signal is used for driving the laser driving chip to generate a driving signal, and the driving signal is used for driving the laser to emit the optical pulse; the other electric trigger signal is used for driving the pulse voltage generation chip to generate pulse voltage, and the pulse voltage is used for driving the phase modulator to load pulse voltage to one optical pulse component;
the upper computer is further configured to draw a curve of the optical pulse power output by the intensity modulation device and the issued delay value under different delay values, obtain a target delay value based on the curve, and delay one of the two electrical trigger signals corresponding to a shorter path time through the control circuit based on the target delay value.
Preferably, in the time domain calibration device, the time domain calibration device has a photoelectric control board, and the photoelectric control board is provided with a serial port for connecting the upper computer and the control circuit;
the laser driving chip, the pulse voltage generating chip and the laser are bound on the photoelectric control board.
Preferably, in the time domain calibration device, an SMA connector is further bound to the photoelectric control board, and the pulse voltage generation chip is connected to the phase modulator through the SMA connector.
Preferably, in the time domain calibration apparatus, an ADC and a PIN tube are further bound to the optoelectronic control board, and the PIN tube is configured to detect an optical power of the synthesized optical pulse to generate an electrical signal representing the optical power;
the ADC is used for carrying out analog-digital conversion on the electric signal to generate a digital signal, and the digital signal is sent to the upper computer through the control circuit.
Preferably, in the time domain calibration device, the upper computer is configured to select the electrical trigger signal corresponding to a shorter path time for delaying.
Preferably, in the time domain calibration device, the upper computer is configured to sequentially issue a plurality of delay values based on a preset initial delay value and a preset step value.
Preferably, in the time domain calibration apparatus, the initial delay value is 0, and the step value is 10ps to 1000 ps.
Preferably, in the time domain calibration apparatus, the intensity modulation apparatus includes: a circulator, a beam splitter, a time delay and the phase modulator;
the optical pulse is incident on the first port of the circulator and is incident on the first port of the beam splitter through the second port of the optical pulse;
the beam splitter divides the optical pulse into two optical pulse components, one optical pulse component is emitted through a second port of the beam splitter and returns to a third port of the beam splitter through the delayer and the phase modulator in sequence, and the other optical pulse component is emitted through a third port of the beam splitter and returns to a second port of the beam splitter through the phase modulator and the delayer in sequence; the phase modulator is used for loading the pulse voltage to one of the optical pulse components; the two light pulse components returning to the beam splitter are combined at the beam splitter to form the combined light pulse, and the combined light pulse is incident to the second port of the circulator through the first port of the beam splitter and is output through the third port of the circulator.
Preferably, in the time domain calibration apparatus, the circulator, the beam splitter, the delayer, and the phase modulator are all polarization maintaining devices.
Preferably, in the time domain calibration device, the delayer is an optical fiber delay line.
The invention also provides a time domain calibration method of the optical pulse and the electric pulse, which is used for an intensity modulation device, wherein the intensity modulation device is used for carrying out intensity modulation on the incident optical pulse, dividing the optical pulse into two optical pulse components, and synthesizing and outputting the two optical pulse components after pulse voltage is loaded on one optical pulse component;
the time domain calibration method comprises the following steps:
carrying out parameter configuration, configuring the driving parameters of the laser for a laser driving chip, and configuring pulse voltage parameters for a pulse voltage generating chip; the laser is used for emitting the optical pulse;
issuing a delay value, wherein the delay value is used for changing the relative time of the two electric trigger signals; one electrical trigger signal is used for driving the laser driving chip to generate a driving signal, and the driving signal is used for driving the laser to emit the optical pulse; the other electric trigger signal is used for driving the pulse voltage generation chip to generate pulse voltage, and the pulse voltage is used for driving the phase modulator to load pulse voltage to one optical pulse component;
under different delay values, drawing a curve of the optical pulse power output by the intensity modulation device and the issued delay value;
acquiring a target delay value based on the curve;
delaying, by the control circuit, one of the two electrical trigger signals corresponding to a shorter path time based on the target delay value.
Preferably, in the time domain calibration method, the issuing delay value includes: and sequentially issuing a plurality of delay values based on the preset initial delay value and the step value.
Preferably, in the time domain calibration method, the delaying, by the control circuit, one of the two electrical trigger signals corresponding to the shorter path time includes:
and selecting the electric trigger signal corresponding to the shorter path time for delaying.
As can be seen from the above description, in the time domain calibration device and method for optical pulses and electrical pulses provided in the technical solution of the present invention, an upper computer may automatically issue a plurality of different delay values, and draw a curve of the power of the optical pulse output by the intensity modulation device and the issued delay values in different delay values, and obtain a target delay value based on the curve, so that one of the two electrical trigger signals corresponding to a shorter path time may be delayed based on the target delay value. Therefore, the technical scheme of the invention can realize the automatic alignment of the optical pulse and the electric pulse in the phase modulator, and has the advantages of simple operation, small workload and high efficiency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an intensity modulation apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a time domain calibration apparatus for use with the intensity modulation apparatus of FIG. 1;
FIG. 3 is a timing diagram of a pulse voltage and a pulse of light according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an apparatus for time-domain calibration of optical pulses and electrical pulses according to an embodiment of the present invention;
fig. 5 is a flowchart of a method of time domain calibration according to an embodiment of the present invention;
FIG. 6 is a flowchart of time domain calibration performed by the time domain calibration method according to the embodiment of the present invention;
FIG. 7 is a graph of delay value versus optical power provided by an embodiment of the present invention;
FIG. 8 is a timing diagram of the time-domain calibrated optical pulse component and the pulse voltage according to an embodiment of the present invention;
fig. 9 is a timing diagram of an optical pulse component and a pulse voltage after another time domain calibration according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
In general, an intensity modulation apparatus is used for intensity-modulating an incident optical pulse (signal light), dividing the optical pulse into two optical pulse components, applying a pulse voltage to one optical pulse component, modulating a phase difference between the two optical pulse components, and outputting a combined optical pulse of the two optical pulse components, and one embodiment of the intensity modulation apparatus is as shown in fig. 1.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an intensity modulation apparatus according to an embodiment of the present invention, where the intensity modulation apparatus is a self-stabilizing intensity modulation apparatus based on a sagnac bidirectional loop optical path, and includes: the polarization-maintaining optical fiber polarization-maintaining phase modulator comprises a polarization-maintaining circulator PMCIR, a polarization-maintaining beam splitter PMBS, a polarization-maintaining optical fiber delay line FDL and a polarization-maintaining phase modulator PM, wherein the four elements form a Sagnac interference loop.
The optical pulse emitted from the laser is incident on the polarization maintaining beam splitter PMBS through the first port C1 of the polarization maintaining circulator pmir, and optical pulse components transmitted in both clockwise and counterclockwise directions are formed. The times at which the two optical pulse components arrive at the polarization maintaining phase modulator PM are staggered by the polarization maintaining fiber delay line FDL. When one of the optical pulse components reaches the polarization maintaining phase modulator PM, the polarization maintaining phase modulator PM loads pulse voltage to the optical pulse component, when the other optical pulse component reaches the polarization maintaining phase modulator PM, the polarization maintaining phase modulator PM does not load pulse voltage to the optical pulse component, so that the two optical pulse components are modulated to form a phase difference, and finally the two optical pulse components simultaneously return to the polarization maintaining beam splitter PMBS again to generate interference. When pulse voltages with different amplitudes are loaded, different phase differences can be generated between two optical pulse components, and interference results are different, so that adjustable intensity modulation is realized. Because the two optical pulse components in the interference ring pass through the same path, the two optical pulse components can be mutually offset by the influence of the external environment on the interference ring, and compared with the common intensity modulation scheme, the mode shown in fig. 1 has better intensity modulation range, precision, contrast, stability and controllability.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a time domain calibration apparatus for the intensity modulation apparatus shown in fig. 1, the time domain calibration apparatus comprising: an FPGA (programmable gate array), a pulse voltage generating chip 11, an SMA connector 12, a laser driving chip 13 and a laser 14 which are arranged on the photoelectric control board 10. The laser 14 is used to generate the above-mentioned light pulses, which are incident on a first port C1 of the polarization maintaining circulator PMCIR in fig. 1. The laser 14 emits an optical pulse through an optical path formed by the intensity modulation device shown in fig. 1, and forms two optical pulse components to reach the polarization maintaining phase modulator PM shown in fig. 1.
As shown in fig. 2, the FPGA simultaneously sends two electrical trigger signals according to a certain period frequency, and the two electrical trigger signals are respectively sent to the laser driving chip 13 and the pulse voltage generating chip 11, so that the laser driving chip 13 generates a driving signal, and the pulse voltage generating chip 11 generates a pulse voltage. The pulse voltage output by the pulse voltage generating chip 13 is sent to the polarization maintaining phase modulator PM through the coaxial cable, and the laser driving chip 13 drives the laser 14 to emit light pulses through the driving signal, and the light pulses reach the polarization maintaining phase modulator PM through the light path. The pulse voltage and the light pulse have to correspond to each other one by one, and dislocation cannot occur, that is, the pulse voltage corresponding to the first pair (two) of the electric trigger signals sent by the FPGA and one of the light pulse components need to reach the PM at the same time, so that the pulse voltage is loaded on the one light pulse component. However, the travel time of the first path and the second path cannot be completely equal, so that one of the electric trigger signals of the FPGA needs to be sent out in a delayed manner, and the final pulse voltage (i.e. the electric pulse) and the final optical pulse (one of the optical pulse components) reach the polarization-maintaining phase modulator PM at the same time to complete phase modulation. How to determine the delay value is critical for the alignment of the optical and electrical pulses at the polarization maintaining phase modulator PM.
Referring to fig. 3, fig. 3 is a timing chart of a pulse voltage and an optical pulse according to an embodiment of the present invention, where a relationship between two optical pulse components of an optical pulse and a pulse voltage on a time axis is as shown in fig. 3, and a delay value is set, that is, a relative position of the optical pulse components and the pulse voltage on the time axis is changed.
As shown in fig. 3, the pulse voltage is a periodic signal, and the ideal case of the alignment of the optical pulse is that one of the optical pulse components is at a high level of the pulse voltage, the other optical pulse component is at a low level of the pulse voltage, and neither of the optical pulse components is too close to the falling edge (or the rising edge) of the pulse voltage, so as to avoid the problem of unstable modulation result caused by the falling edge (or the rising edge) of the optical pulse component due to signal drift.
The optical pulse component at a high level is subjected to phase modulation, the optical pulse component at a low level is not subjected to phase modulation, and a phase difference is generated between the two optical pulse components. If the voltage difference between the two optical pulse components is not changed, the phase difference is also not changed, and finally the light intensity of the interference synthesis is also not changed.
In order to find out the target delay value, the conventional method is to estimate the difference between the travel time of the first path and the travel time of the second path, namely to find out the approximate time interval of the target delay value. Again, different delay values are manually set in this interval, and the target delay value is determined based on the optical power output by the third port C3 of the polarization maintaining circulator PMCIR.
The difference between the travel time of the first path and the travel time of the second path needs to be measured by an oscilloscope to find out the respective transmission time of the two electrical trigger signals on the photoelectric control board 10, and then the transmission time of the corresponding signals on the optical path and the coaxial cable is estimated, so as to determine the approximate time interval of the target delay value. Based on the time interval, the variation trend of the optical power of the third port C3 is monitored by manually issuing different delay values to determine the final target delay value. When the method is used for searching the target delay value, the issued delay value needs to be repeatedly modified and finely adjusted, the manual work in the whole process is long, about 1 hour is needed, the whole debugging working hour is not favorably compressed, the working efficiency is low, and the method is especially not favorable for the mass production of products.
The embodiment of the invention provides a scheme capable of automatically carrying out time domain calibration on the optical pulse and the electric pulse, and a target delay value can be automatically found within about 2 minutes. And an oscilloscope is not needed to test the signal transmission time, the operation is simple, the circuit structure is simple, and the cost is lower.
Referring to fig. 4, fig. 4 is a schematic structural diagram of a time domain calibration apparatus for optical pulses and electrical pulses according to an embodiment of the present invention, wherein the time domain calibration apparatus 30 is used for the intensity modulation apparatus 20 to perform time domain alignment of the optical electrical pulses on the phase modulator 24 in the intensity modulation apparatus 20.
The intensity modulation device 20 is configured to perform intensity modulation on an incident light pulse, divide the light pulse into two light pulse components, apply a pulse voltage to one of the light pulse components, modulate a phase difference between the two light pulse components, and output a synthesized light pulse of the two light pulse components.
The time domain calibration device 30 comprises: the device comprises an upper computer 31, a control circuit 32, a laser driving chip 33 and a pulse voltage generating chip 34. The upper computer 31 is used for configuring driving parameters of a laser 35 for the laser driving chip 33 and configuring pulse voltage parameters for the pulse voltage generating chip 34 through the control circuit 32; the laser 35 is used to emit the light pulse. The control circuit 32 includes, but is not limited to, an FPGA.
The control circuit 32 is configured to obtain a delay value issued by the upper computer 31, and generate two electrical trigger signals based on the delay value; one of the electrical trigger signals is used for driving the laser driving chip 33 to generate a driving signal, and the driving signal is used for driving the laser 35 to emit the optical pulse; the other of the electrical trigger signals is used to drive the pulse voltage generating chip 34 to generate a pulse voltage, and the pulse voltage is used to drive the phase modulator 24 to apply a pulse voltage to one of the optical pulse components. The two electrical trigger signals may be an electrical trigger signal 1 and an electrical trigger signal 2, for example, it may be set that the laser driving chip 33 is driven by the electrical trigger signal 1 to generate a driving signal, the pulse voltage generating chip 34 is driven by the electrical trigger signal 2 to generate a pulse voltage, the electrical trigger signal 1, the driving signal, the optical pulse and two optical pulse components are sequentially transmitted in a set path (i), and the electrical trigger signal 2 and the pulse voltage are sequentially transmitted in a set path (ii).
The upper computer 31 is further configured to draw a curve of the optical pulse power output by the intensity modulation device 20 and the issued delay value at different delay values, obtain a target delay value based on the curve, and delay, by using the control circuit 32, one of the two electrical trigger signals corresponding to a shorter path time based on the target delay value.
As shown in fig. 4, the time domain calibration device 30 has a photoelectric control board 36, and the photoelectric control board 36 is provided with a serial port 37 for connecting the upper computer 31 and the control circuit 32; the laser driving chip 33, the pulse voltage generating chip 34 and the laser 35 are bound on the photoelectric control board 36. The photoelectric control board 36 may be provided with bonding pads, and the laser driving chip 33, the pulse voltage generating chip 34, and the laser 35 may be directly soldered to the corresponding bonding pads.
Optionally, an SMA connector 38 is further bound on the photoelectric control board, and the pulse voltage generating chip 34 is connected to the phase modulator 24 through the SMA connector 38. The SMA connectors 38 are directly soldered to the corresponding pads.
In the embodiment of the present invention, an ADC (analog-to-digital converter) and a PIN tube 39 are further bound on the photoelectric control board 36, where the PIN tube 39 is configured to detect the optical power of the synthesized optical pulse to generate an electrical signal representing the optical power; the ADC is configured to perform analog-to-digital conversion on the electrical signal to generate a digital signal, and send the digital signal to the upper computer 31 through the control circuit 32. The ADC is not shown in fig. 4. And the ADC is directly welded and fixed with the corresponding bonding pad. The ADC is connected to the control circuit 32 and connected to the upper computer 31 through a serial port 37.
The upper computer 31 is used for selecting the electric trigger signal corresponding to the shorter path time to delay. The propagation speeds of the optical signal and the electrical signal can be equivalent to each other, so that the path time with a long transmission total path is long, and the path time with a short transmission total path is short. Therefore, the electric trigger signal corresponding to the shorter path time can be determined directly according to the path length corresponding to the two electric trigger signals so as to delay the electric trigger signal. The path I and the path II respectively correspond to an electric trigger signal, and the length of the two paths can be directly measured by manual visual observation or by a measuring tool so as to determine the electric trigger signal with shorter path time. The upper computer can select the electric trigger signal corresponding to the short path time to delay based on the preset and stored data representing the short path time, or directly acquire the manually input data representing the short path time in the working process to select the electric trigger signal corresponding to the short path time to delay. The mode can determine to select the electric trigger signal corresponding to the shorter path time through macroscopic transmission total path distance so as to carry out time delay control. The method does not need to accurately measure the lengths of the path I and the path II, and only needs to qualitatively compare the lengths of the path I and the path II.
The upper computer 31 is used for issuing a plurality of delay values in sequence based on a preset initial delay value and a preset step value. Optionally, the initial delay value is 0, and the step value is 10ps to 1000 ps.
The intensity modulation device 20 includes: a circulator 21, a beam splitter 22, a time delay 23 and said phase modulator 24. The light pulse is incident on the first port C1 of the circulator 21 and on the first port B1 of the beam splitter 22 through the second port C2 thereof. The beam splitter 22 splits the optical pulse into two optical pulse components, one of which is emitted through the second port B2 of the beam splitter 22 and returned to the third port B3 of the beam splitter 22 via the delay 23 and the phase modulator 24 in order, and the other of which is emitted through the third port B3 of the beam splitter 22 and returned to the second port B2 of the beam splitter 22 via the phase modulator 24 and the delay 23 in order; the phase modulator 24 is used for loading the pulse voltage to one of the optical pulse components; the two light pulse components returned to the beam splitter 22 are combined at the beam splitter 22 to form the combined light pulse, and the combined light pulse is incident on the second port C2 of the circulator 21 through the first port B1 of the beam splitter 22 and is output through the third port C3 of the circulator 21.
The intensity modulation device 20 is implemented in the same manner as in fig. 1, and operates on the same principle. The circulator 21, the beam splitter 22, the time delay 23 and the phase modulator 24 are all polarization maintaining devices to maintain the polarization state of the transmitted optical signal. The delay device 23 includes, but is not limited to, an optical delay device such as a fiber delay line. Specifically, the circulator 21 is a polarization maintaining circulator pmir, the beam splitter 22 is a polarization maintaining beam splitter PMBS, the delay 23 is a polarization maintaining fiber delay line FDL, and the phase modulator 24 is a polarization maintaining phase modulator PM.
Based on the foregoing embodiment, another embodiment of the present invention further provides a time domain calibration method for optical pulses and electrical pulses, where the time domain calibration method is used to perform time domain calibration on the optical electrical pulses of the intensity modulation apparatus. The time domain calibration method is shown in fig. 5.
Referring to fig. 5, fig. 5 is a flowchart of a method of time domain calibration according to an embodiment of the present invention, where the method includes:
step S11: and carrying out parameter configuration.
Configuring the driving parameters of the laser 35 for the laser driving chip 33 and configuring the pulse voltage parameters for the pulse voltage generating chip 34; the laser 35 is used for emitting the light pulse, so that the laser 35 can normally emit light, and the pulse voltage generating chip 34 can normally output the light pulse.
Step S12: and issuing a delay value.
The delay value is used for changing the relative time of sending out two electric trigger signals; one of the electrical trigger signals is used for driving the laser driving chip 33 to generate a driving signal, and the driving signal is used for driving the laser 35 to emit the optical pulse; the other of the electrical trigger signals is used to drive the pulse voltage generating chip 34 to generate a pulse voltage, and the pulse voltage is used to drive the phase modulator 24 to apply a pulse voltage to one of the optical pulse components.
Step S13: and under different delay values, a curve of the optical pulse power output by the intensity modulation device 20 and the issued delay value is drawn.
Step S14: and acquiring a target delay value based on the curve.
Step S15: based on the target delay value, one of the two electrical trigger signals corresponding to the shorter path time is delayed by the control circuit 32.
Optionally, the issue delay value includes: and sequentially issuing a plurality of delay values based on the preset initial delay value and the step value.
Optionally, the delaying, by the control circuit 32, one of the two electrical trigger signals corresponding to the shorter path time includes: and selecting the electric trigger signal corresponding to the shorter path time for delaying.
The time domain calibration method can be implemented by the time domain calibration device according to the above embodiment, and a platform environment, a connection light path, and an electronic connection line are constructed based on the method shown in fig. 4. After the photoelectric control board 36 is powered on, relevant parameters are configured through the upper computer 31, so that the laser 35 can normally emit light, and the pulse voltage generation chip 34 can normally output the light.
The upper computer 31 can automatically and successively issue delay values from the initial delay value according to a certain step value, and acquire the optical power values corresponding to the synthesized optical pulses output by the intensity modulation device 20 at different delay values through the PIN tube 39. The display interface of the upper computer 31 is provided with a setting key, and the upper computer 31 can be started to automatically draw a curve of the delay value and the optical power by triggering the setting key. The upper computer 31 display interface is provided with a window for displaying the curve in real time. After the upper computer 31 finishes the curve scanning, a target delay value can be automatically calculated according to the scanning data, and the target delay value is directly issued to the control circuit 32, so that the time domain alignment of the optical pulse and the pulse voltage is finished.
The working process of the time domain calibration method according to the embodiment of the present invention is further described below with reference to the time domain calibration apparatus 30 according to the above embodiment.
The laser 35 on the photoelectric control board 36 is connected with the first port C1 of the circulator 21 in the optical path, the third port of the circulator 21 is connected with the PIN tube 39, and the SMA connector 38 is connected with the radio frequency input interface of the phase modulator 24. The upper computer 31 is connected with the photoelectric control board 36 through a serial port 37, and functions of parameter issuing, modification, storage, data acquisition and the like of the photoelectric control board 36 are realized through a control program in the upper computer 31. After the device is built based on the structure shown in fig. 4, a key controls to start curve scanning, the control program of the upper computer 31 can automatically issue a delay value from an initial delay value (such as 0) according to a set step length, the PIN tube 39 monitors the optical power change corresponding to the synthesized optical pulse output by the intensity modulation device 20, and a change curve of the delay value and the optical power is drawn and displayed in the display interface of the upper computer 31.
The operation flow of the time domain calibration device may be as shown in fig. 6, and fig. 6 is a flow chart of performing time domain calibration by using the time domain calibration method according to the embodiment of the present invention, as shown in fig. 6, after the photoelectric control board is powered on, parameter configuration is performed by the upper computer, so that the laser and the pulse voltage generation chip can normally operate, then the upper computer automatically issues a delay value, one-key control starts curve scanning, after curve drawing is completed, a target delay value is automatically calculated, and the target delay value is issued to the control circuit, so that photo-electric pulse alignment is completed.
Fig. 7 shows a curve automatically drawn by the technical solution of the embodiment of the present invention, and fig. 7 is a graph of a delay value and optical power provided by the embodiment of the present invention, and it can be known from fig. 7 that the curve has two adjacent valleys with flat bottoms, and theoretically, the central positions of the two flat valleys can be both used as target delay values, which respectively correspond to the following two ways:
if point a in fig. 7 is set as the target delay value, the time position relationship between the optical pulse component and the pulse voltage is as shown in fig. 8, and fig. 8 is a timing chart of the optical pulse component and the pulse voltage after time domain calibration according to the embodiment of the present invention. The two light pulse components are located on either side of the rising edge of the pulse voltage.
If point B in fig. 7 is set as the target delay value, the time position relationship between the optical pulse component and the pulse voltage is as shown in fig. 9, and fig. 9 is another time-domain calibrated timing chart of the optical pulse component and the pulse voltage according to the embodiment of the present invention. The two light pulse components are located on both sides of the falling edge of the pulse voltage.
Point a or point B is set as a target delay value, that is, a pulse voltage is applied to optical pulse component 2 or optical pulse component 1, and phase modulation is performed.
Because the rising edge time and the falling edge time of the pulse voltage are not exactly the same, the edge jitter will cause a difference between the two. In order to make the pressure difference fluctuation loaded by the optical pulse component smaller and obtain a more stable phase difference value, the technical scheme of the invention selects an edge (a rising edge or a falling edge) with better waveform quality to determine and select the point A or the point B as a target delay value. Specifically, based on the plotted curve, the upper computer 31 calculates the flatness of the bottoms of the two troughs, selects a delay value corresponding to the middle position of the trough with high flatness as a target delay value, and automatically issues the target delay value to the control circuit 32.
The technical scheme of the invention can automatically find and determine the target delay value through the control program of the upper computer, reduces the manual intervention to the maximum extent, can complete the scanning of the delay value-optical power curve in one key, automatically calculates the target delay value according to the scanning data, and completes the issuing of the delay value. In the whole process, all the work of photoelectric pulse alignment can be finished only by manually setting up an environment and clicking a 'curve scanning' key on an upper computer software interface. The method takes about 2 minutes to finish the photoelectric pulse alignment, and compared with the existing method, the method has the advantages of simple system structure, simple operation, small workload, greatly shortened consumed time and greatly improved working efficiency.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. As for the time domain calibration method disclosed in the embodiment, since it corresponds to the time domain calibration device disclosed in the embodiment, the description is relatively simple, and the relevant points can be only described with reference to the corresponding part of the time domain calibration device.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (13)
1. The time domain calibration device for the optical pulse and the electric pulse is characterized in that the time domain calibration device is used for an intensity modulation device, the intensity modulation device is used for carrying out intensity modulation on an incident optical pulse, dividing the optical pulse into two optical pulse components, loading pulse voltage on one optical pulse component, modulating the two optical pulse components to form a phase difference, and then outputting a synthesized optical pulse of the two optical pulse components;
the time domain calibration device comprises: the device comprises an upper computer, a control circuit, a laser driving chip and a pulse voltage generating chip;
the upper computer is used for configuring the driving parameters of the laser for the laser driving chip through the control circuit and configuring pulse voltage parameters for the pulse voltage generating chip; the laser is used for emitting the optical pulse;
the control circuit is used for acquiring a delay value issued by the upper computer and generating two electric trigger signals based on the delay value; one electrical trigger signal is used for driving the laser driving chip to generate a driving signal, and the driving signal is used for driving the laser to emit the optical pulse; the other electric trigger signal is used for driving the pulse voltage generation chip to generate pulse voltage, and the pulse voltage is used for driving the phase modulator to load pulse voltage to one optical pulse component;
the upper computer is further configured to draw a curve of the optical pulse power output by the intensity modulation device and the issued delay value under different delay values, obtain a target delay value based on the curve, and delay one of the two electrical trigger signals corresponding to a shorter path time through the control circuit based on the target delay value.
2. The time domain calibration device of claim 1, wherein the time domain calibration device has a photoelectric control board provided with a serial port for connecting the upper computer and the control circuit;
the laser driving chip, the pulse voltage generating chip and the laser are bound on the photoelectric control board.
3. The time domain calibration device of claim 2, wherein an SMA connector is further bonded to the optoelectronic control board, and the pulse voltage generating chip is connected to the phase modulator through the SMA connector.
4. The time domain calibration device of claim 2, wherein an ADC and a PIN tube are further bonded to the optoelectronic board, and the PIN tube is configured to detect an optical power of the synthesized optical pulse to generate an electrical signal representing the optical power;
the ADC is used for carrying out analog-digital conversion on the electric signal to generate a digital signal, and the digital signal is sent to the upper computer through the control circuit.
5. The time domain calibration device of claim 1, wherein the upper computer is configured to select the electrical trigger signal corresponding to the shorter path time for delaying.
6. The time domain calibration device of claim 1, wherein the upper computer is configured to sequentially issue a plurality of delay values based on a preset initial delay value and a step value.
7. The time domain calibration device of claim 6, wherein the initial delay value is 0 and the step value is 10-1000 ps.
8. The time domain calibration device of any one of claims 1-7, wherein the intensity modulation device comprises: a circulator, a beam splitter, a time delay and the phase modulator;
the optical pulse is incident on the first port of the circulator and is incident on the first port of the beam splitter through the second port of the optical pulse;
the beam splitter divides the optical pulse into two optical pulse components, one optical pulse component is emitted through a second port of the beam splitter and returns to a third port of the beam splitter through the delayer and the phase modulator in sequence, and the other optical pulse component is emitted through a third port of the beam splitter and returns to a second port of the beam splitter through the phase modulator and the delayer in sequence; the phase modulator is used for loading the pulse voltage to one of the optical pulse components; the two light pulse components returning to the beam splitter are combined at the beam splitter to form the combined light pulse, and the combined light pulse is incident to the second port of the circulator through the first port of the beam splitter and is output through the third port of the circulator.
9. The time domain calibration device of claim 8, wherein said circulator, said beam splitter, said delay, and said phase modulator are polarization maintaining devices.
10. The time domain calibration device of claim 8, wherein said delay is a fiber delay line.
11. A time domain calibration method of optical pulse and electric pulse is characterized in that the time domain calibration method is used for an intensity modulation device, the intensity modulation device is used for carrying out intensity modulation on incident optical pulse, dividing the optical pulse into two optical pulse components, and synthesizing and outputting the two optical pulse components after pulse voltage is loaded on one optical pulse component;
the time domain calibration method comprises the following steps:
carrying out parameter configuration, configuring the driving parameters of the laser for a laser driving chip, and configuring pulse voltage parameters for a pulse voltage generating chip; the laser is used for emitting the optical pulse;
issuing a delay value, wherein the delay value is used for changing the relative time of the two electric trigger signals; one electrical trigger signal is used for driving the laser driving chip to generate a driving signal, and the driving signal is used for driving the laser to emit the optical pulse; the other electric trigger signal is used for driving the pulse voltage generation chip to generate pulse voltage, and the pulse voltage is used for driving the phase modulator to load pulse voltage to one optical pulse component;
under different delay values, drawing a curve of the optical pulse power output by the intensity modulation device and the issued delay value;
acquiring a target delay value based on the curve;
delaying, by a control circuit, one of the two electrical trigger signals corresponding to a shorter path time based on the target delay value.
12. The time domain calibration method of claim 11, wherein the issuing delay value comprises: and sequentially issuing a plurality of delay values based on the preset initial delay value and the step value.
13. The time-domain calibration method of claim 11, wherein said delaying, by said control circuit, a corresponding shorter path time of one of said two electrical trigger signals comprises:
and selecting the electric trigger signal corresponding to the shorter path time for delaying.
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