CN116026567A - Automatic testing method and system for optimal working point of expansion cavity sweep frequency source - Google Patents
Automatic testing method and system for optimal working point of expansion cavity sweep frequency source Download PDFInfo
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Abstract
The invention belongs to the field of laser testing, and provides an automatic testing method and system for an optimal working point of an expansion cavity sweep frequency source, wherein maximum output power and minimum driving current of the expansion cavity sweep frequency source are determined through analysis of distribution trajectory of tail fiber lasing power and injection current of the expansion cavity sweep frequency source; determining an optimal operating current point by analyzing the tuning wavelength and the tolerance current distribution trajectory; obtaining a part track line of the tuning wavelength and the control temperature by testing resonance output wavelength distribution data under different control temperatures, and analyzing the tuning wavelength and the control temperature distribution track line to determine an optimal working control temperature point; and forming an optimal working point of the expansion cavity sweep frequency source based on the optimal working current point and the optimal working control temperature point, and outputting the optimal working point. The invention solves the problem that the traditional on-chip testing system can not effectively characterize the compatibility of the overall performance of the extension cavity resonance unit to the sweep frequency source system to cause large difference of the output index performance of the sweep frequency source.
Description
Technical Field
The invention belongs to the technical field of laser testing, and particularly relates to an automatic testing method and system for an optimal working point of an expansion cavity sweep frequency source.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
The extended cavity frequency sweep source (also called as free space optical external cavity frequency sweep laser light source for short, FS-ECSS) has been widely applied to the fields of high-speed coherent optical communication network based on high-order optical modulation format, optical fiber three-dimensional shape sensing of cross-correlation frequency domain decoupling, trace gas detection of linear sweep, automatic driving and the like due to the outstanding advantages of single longitudinal mode, narrow linewidth, continuously adjustable output wavelength, no mode jump of full wave band, low phase noise and the like, but in the spectrum output process of the traditional FS-ECSS, the realization of the wide-range, no mode jump, narrow linewidth linear continuous sweep laser output is seriously dependent on the accurate prejudgment of the optimal value of the running state of an extended cavity resonance unit.
The traditional on-chip testing system usually calibrates the characteristic parameters of the gain seed sources by using a probe and a testing instrument before the gain seed sources are processed and are not diced, the calibration data of the characteristic parameters of each tested gain seed source is recorded by using a storage module, the calibration data is inverted into a certain process parameter graph capable of judging the electrical performance of the gain seed sources by using a complex interaction analysis algorithm, and the elimination of the gain seed sources with incomplete structure and unqualified electrical performance is realized by comparing with the standard value, but the optical characteristic parameters of the gain seed sources of the sweep frequency source cannot be effectively represented. At present, the test of the optical characteristic parameters of the gain seed source mainly carries out manual calibration on several parameters such as spectrum and the like by an optical coupling output mode, and the calibration result is easily influenced by artificial subjective factors, so that the overall performance parameters of the sample gain seed source are difficult to be compatible with the FS-ECSS. Obviously, the traditional on-chip test system is used as a test device, so that the electrical characteristics of the sample gain seed source can be calibrated, and for gain seed sources with different batches, different waveguide beam emergence angles and different lasing center wavelengths, the calibration process of the optical characteristic parameters of the sample gain seed source is complex, time-consuming, larger in error and not universal due to the factors of threshold current, 3dB bandwidth, diversification of different waveguide beam emergence angles and the like, so that the application requirements of FS-ECSS in the field of high-speed coherent optical communication are difficult to meet; meanwhile, the non-targeted gain seed source characteristic parameter testing system also causes the inefficiency and the increase of cost in the testing process.
In addition, the sweep frequency source system constructed by the conventional hybrid integrated extension cavity feedback mode is relatively complex in structure, mode jump trend monitoring is generally obtained by adopting a method of locally amplifying a specific slope algorithm of the spontaneous emission power spectrum, and the phase compensation unit is finely adjusted through an on-line adjustment strategy, so that the longitudinal mode jump probability is reduced. Obviously, the hybrid integrated type extended cavity frequency sweep source working based on the running state on-line monitoring and adjusting technology is used as a testing device, and a hybrid compensation algorithm model needs to be repeatedly constructed to calculate a fine adjustment strategy of the phase compensation unit, so that the whole machine assembly and debugging process of the extended cavity continuous frequency sweep source is low in efficiency, the system structure and the self-feedback compensation algorithm are complex, time-consuming and weak in robustness.
Disclosure of Invention
In order to solve the problems, the invention provides an automatic test method and an automatic test system for the optimal working point of an extended cavity frequency sweep source, and solves the problems that the conventional on-chip test system has complicated calibration process for the characteristic working parameters of a single-tube gain seed source, the whole set of test system has a complex structure, and the test for the working parameters of the seed source cannot effectively represent the compatibility of the overall performance of an extended cavity resonance unit to the frequency sweep source system, so that the performance difference of output indexes of the frequency sweep source is large.
According to some embodiments, the first scheme of the invention provides an automatic testing method for an optimal working point of an expansion cavity sweep frequency source, which adopts the following technical scheme:
an automatic test method for an optimal working point of an expansion cavity sweep frequency source comprises the following steps:
obtaining distribution trajectories of the tail fiber laser power and the injection current of the sweep source of the expansion cavity by testing distribution data of the resonant output optical power under different driving currents, and analyzing the distribution trajectories of the tail fiber laser power and the injection current of the sweep source of the expansion cavity to determine the maximum output power and the minimum driving current of the sweep source of the expansion cavity;
the maximum output power and the minimum driving current of the extended cavity sweep frequency source are used as limiting values, the distribution data of the resonant output wavelength under a single driving current are tested to obtain a distribution track line of the tuning wavelength and the tolerance current, and the distribution track line of the tuning wavelength and the tolerance current is analyzed to determine an optimal working current point;
obtaining a part track line of the tuning wavelength and the control temperature by testing resonance output wavelength distribution data under different control temperatures, and analyzing the tuning wavelength and the control temperature distribution track line to determine an optimal working control temperature point;
and forming an optimal working point of the expansion cavity sweep frequency source based on the optimal working current point and the optimal working control temperature point, and outputting the optimal working point.
According to some embodiments, the second aspect of the present invention provides an automatic testing system for an optimal working point of an extended cavity sweep source, which adopts the following technical scheme:
an automatic test system for an extended cavity swept source optimal operating point, comprising:
the expansion cavity sweep frequency source consists of a single-tube gain seed source integrated unit, a damping bearing unit, a control circuit and an optical interface;
a high-precision incubator for simulating the operating environment temperatures that an extended cavity swept source may face;
the program-controlled attenuator is controlled by the control computer and is used for attenuating the resonant laser power of the sweep source of the expansion cavity, so that the optical wavelength meter is ensured to be under the damage threshold working state in real time;
the optical switch is controlled by the control computer and is used for switching optical signal output channels of the optical power meter and the optical wavelength meter;
the optical power meter is used for extracting the resonant optical power of the gain chip under different injection currents;
an optical wavelength meter for recording of the lasing wavelength;
the control computer provides instruction initialization and driving signals of the control circuit, temperature regulation signals of the high-precision incubator, attenuation gear initialization and attenuation gear switching of the program-controlled attenuator, instruction initialization of the optical switch, test channel switching and synchronous triggering acquisition signals of the optical power meter and the optical wavelength meter, and the control computer receives and processes resonance power and lasing wavelength distribution data information recorded in real time in the optical power meter and the optical wavelength meter.
Further, the single-tube gain seed source integrated unit mainly comprises a gain chip, a thermistor, a thermo-electric refrigerator, a range-extending displacement mechanism and a gold wire bonding connecting wire;
the gain chip is used for generating a free space optical external cavity strong feedback seed source; the said
The thermistor is used for monitoring and feeding back the junction temperature of the gain chip;
the thermo-electric refrigerator is used for temperature field adjustment;
the range-extending displacement mechanism is a stepping motor integrated with piezoelectric ceramics and is used for controllably tuning the cavity length of the expansion cavity sweep frequency source;
the gold wire bonding connection wire is used for electric connection.
Further, the damping bearing unit is used for bearing the expansion cavity sweep frequency source and reducing damping;
the control circuit is controlled by the control computer and used for loading the driving current of the single-tube gain seed source integrated unit;
the optical interface is used for guiding out the sweep frequency laser signals.
Compared with the prior art, the invention has the beneficial effects that:
the invention solves the problems that the calibration process of the traditional on-chip testing system on the single-tube gain seed source characteristic working parameters is complicated, the whole set of testing system has a complex structure, and the test on the seed source working parameters can not effectively represent the compatibility of the overall performance of the extended cavity resonance unit to the sweep frequency source system, so that the performance difference of the sweep frequency source output indexes is large.
The invention solves the problems of low efficiency, complex structure and algorithm in the whole machine assembly and debugging process of the continuous sweep frequency source of the extension cavity caused by the traditional hybrid integrated extension cavity sweep frequency source depending on the technologies of cavity mode monitoring, phase hybrid compensation and the like; the problems that the calibration process of the gain seed source optical characteristic parameters in the FS-ECSS system is complex, time-consuming, large in error and not universal are solved;
according to the invention, through accurate pre-judgment of the optimal value of the running state of the extended cavity resonance unit, the assembly and debugging efficiency of the FS-ECSS complete machine is improved, complex monitoring algorithms and units are removed, and the cost is reduced; further expands the application range of the broad-range non-skip mode FS-ECSS, increases the application scene for the broad-range non-skip mode FS-ECSS, and promotes the rapid development of the broad-range non-skip mode FS-ECSS industry.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
FIG. 1 is a schematic diagram of an automatic test and analysis flow of an optimum operating point of an extended cavity swept source according to an embodiment of the invention;
FIG. 2 is a schematic diagram of a second embodiment of an automatic test and analysis process for an optimal operating point of an extended cavity swept source;
FIG. 3 is a flow chart of a method for calculating a minimum driving current allowed to be loaded according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a calculation flow of the optimal operating current point DC_OP according to an embodiment of the invention;
FIG. 5 is a schematic diagram of a calculation flow of the optimal operation control temperature point T_OP according to an embodiment of the invention;
FIG. 6 is a schematic diagram of an automatic test system for the optimum operating point of the swept source of the expansion cavity according to the embodiment of the invention;
FIG. 7 is a schematic diagram of an embodiment of an automatic test of an optimum operating point of an extended cavity swept source according to the embodiments of the invention;
fig. 8 is a schematic structural diagram of a single-tube gain seed source integrated unit according to an embodiment of the present invention.
Detailed Description
The invention will be further described with reference to the drawings and examples.
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
Embodiments of the invention and features of the embodiments may be combined with each other without conflict.
Noun interpretation:
on-chip test system: the system mainly comprises a probe station, a vector network analyzer, a semiconductor characteristic analyzer, an epitaxial wafer and the like, and is a detection system for testing the characteristics of the chip such as electricity and the like when the chip is not diced into independent bars.
Example 1
As shown in fig. 1 and 2, the present embodiment provides an automatic test method for an optimum working point of an extended cavity sweep source. In this embodiment, the method includes the steps of:
obtaining distribution trajectories of the tail fiber laser power and the injection current of the sweep source of the expansion cavity by testing distribution data of the resonant output optical power under different driving currents, and analyzing the distribution trajectories of the tail fiber laser power and the injection current of the sweep source of the expansion cavity to determine the maximum output power and the minimum driving current of the sweep source of the expansion cavity;
the maximum output power and the minimum driving current of the extended cavity sweep frequency source are used as limiting values, the distribution data of the resonant output wavelength under a single driving current are tested to obtain a distribution track line of the tuning wavelength and the tolerance current, and the distribution track line of the tuning wavelength and the tolerance current is analyzed to determine an optimal working current point;
obtaining a part track line of the tuning wavelength and the control temperature by testing resonance output wavelength distribution data under different control temperatures, and analyzing the tuning wavelength and the control temperature distribution track line to determine an optimal working control temperature point;
and forming an optimal working point of the expansion cavity sweep frequency source based on the optimal working current point and the optimal working control temperature point, and outputting the optimal working point.
The test and analysis flow diagrams of the embodiment are shown in fig. 1 and 2, and through further analysis of test traces such as the extension cavity sweep source tail fiber lasing power and injection current, the tuning wavelength and tolerance current, the tuning wavelength and control temperature, the automatic analysis of the characteristic parameters of the working points of the extension cavity resonance units is realized, so that the distribution data of the intrinsic working parameters of single-tube gain seed source integrated units of different batches and different packaging processes are obtained, and the high-efficiency and high-accuracy test of the characteristic parameters of the optimal working points of the extension cavity resonance units is realized, wherein the specific steps are as follows:
step 101: the control computer (7) remotely controls the starting of the expansion cavity sweep frequency source (1) and goes to step 102;
step 102: the control computer (7) reads the driving current parameter of the gain chip (201) driven by the control circuit (103) in the expansion cavity sweep source (1), the control temperature parameter of the thermistor (202), the driving current parameter of the thermo-electric refrigerator (203), the space position parameter of the range-increasing displacement mechanism (204), the initial state parameters such as the attenuation gear of the program-controlled attenuator (3) and the channel position CP 1-2 of the optical switch (4), and the step (103) is carried out;
step 103: the control computer (7) remotely controls and starts the high-precision incubator (2) and reads initial state parameters such as the temperature value of the high-precision incubator (2), and the like, and the step 104 is shifted to;
step 104: the user inputs the setting temperature ST of the high-precision incubator (2), the sampling rate PS of the optical power meter (5) connected with the channel CP [1], the wavelength resolution WR of the optical wavelength meter (6) connected with the channel CP [2], the driving currents DC [ 1-M ] of the gain chip (201), the control temperature RT of the thermistor (202) and the driving pulse signals QS [ 1-N ] of the range-extending displacement mechanism (204) in the single-tube gain seed source integrated unit (101), and the step 105 is carried out;
step 105: the control computer (7) adjusts the attenuation value introduced by the program-controlled attenuator (3) to the lowest gear ATT, the remote start optical switch (4) is arranged at the channel position CP [1], the control circuit (103) loads the gain chip (201) which loads the driving currents DC [1] to M ] in the single-tube gain seed source integrated unit (101) respectively, measures and records the resonance output optical power data generated by the program-increasing displacement mechanism (204) by M driving currents under the excitation of N driving pulse signals respectively, and then the step 106 is carried out;
step 106: after the resonance output light power data automatic test is completed, the control computer (7) reads resonance output light power distribution data P1-N1-M, and the process goes to step 107;
step 107: analyzing the resonant output light power distribution data P [ 1-N ] [ 1-M ] to obtain the extended cavity sweep source tail fiber lasing power and injection current distribution tracks P [1] [ 1-M ], P [ C ] [ 1-M ] and P [ N ] [ 1-M ], wherein C= (N+1)/2 when N is an odd number and C=N/2 when N is an even number, and turning to step 108; the analysis of the resonant output optical power distribution data herein refers to the construction of a two-dimensional plane curve of the position points corresponding to the injection current (horizontal axis) and the optical power (vertical axis) of the extracted resonant output optical power distribution data when different driving pulses (initial value [1], intermediate value [ C ], final value [ N ]) are loaded to the extended-range displacement mechanism, so as to obtain the extended-range sweep-source pigtail lasing power and the injection current distribution trace.
Step 108: analyzing the distribution trace PC 1-M of the tail fiber laser power and the injection current of the extended cavity sweep source to obtain the maximum output power Pmax of the extended cavity sweep source, wherein Pmax=PC-M, and then the step 109 is performed; it should be noted that, due to the particularity of the sweep source of the expansion cavity, the maximum output power basically occurs when the stroke-increasing displacement mechanism moves to the position in the middle of the whole stroke, that is, when the loading driving pulse is the middle value [ C ], and when the driving current is the maximum, that is, [ M ].
Step 109: analyzing the distribution trace P1-M and P1-M N1-M of the spread cavity sweep source tail fiber laser power and injection current to obtain the minimum driving current DCmin allowed to be loaded by the spread cavity sweep source full-band output, wherein the specific steps are shown in step 201 and step 110;
step 110: the control computer (7) reads the driving pulse signal number C and the driving current number M corresponding to the maximum output power Pmax of the extension cavity sweep frequency source, loads C and M to the gain chip (201) in the extended range displacement mechanism (204) and the single-tube gain seed source integrated unit (101) respectively, and goes to step 111;
step 111: the control computer (7) adjusts the attenuation gear of the program-controlled attenuator (3) to be added with 1, judges whether the resonance optical power PA collected by the optical power meter (5) is less than or equal to 9dBm, if so, the step 113 is switched to, otherwise, the step 112 is switched to;
step 112: the control computer (7) adjusts the attenuation gear of the program-controlled attenuator (3) and adds 1 again, judges whether the resonance optical power PA collected by the optical power meter (5) is less than or equal to 9dBm, if so, the step 113 is switched to, otherwise, the step 112 is switched to;
step 113: the control computer (7) places the optical switch (4) at a channel position CP 2, the control circuit (103) loads gain chips (201) respectively loading driving currents DC [ DCmin+100 mA-M ] in the single-tube gain seed source integrated unit (101), and the resonance output wavelength data generated by M- (DCmin+100 mA) +1 driving currents under the condition that N driving pulse signals are excited by the range-extending displacement mechanism (204) are measured and recorded, and the step is transferred to step 114;
step 114: after the resonance output wavelength data automatic test is completed, the control computer (7) reads resonance output wavelength distribution data W [ 1-N ] [ DCmin+100 mA-M ], and goes to step 115;
step 115: analyzing the resonance output wavelength distribution data W [ 1-N ] [ DCmin+100 mA-M ] to obtain a tuning wavelength and tolerance current distribution trace WE, and analyzing the distribution trace WE to obtain an optimal working current point DC_OP, wherein the specific steps are shown in step 301 and the step 116 is carried out; it should be noted that, herein, analyzing the resonant output wavelength distribution data to obtain a tuned wavelength and tolerance current distribution trace refers to performing two-dimensional plane curve construction of position points corresponding to injection current (horizontal axis) and optical wavelength (vertical axis) on the extracted resonant output wavelength distribution data when loading different driving pulses to the extended range displacement mechanism, so as to obtain the tuned wavelength and tolerance current distribution trace.
Step 116: the control computer (7) loads driving current DC_OP to a gain chip (201) in the single-tube gain seed source integrated unit (101) through a control circuit (103), controls the control temperature T1= [ RT-2-RT+2℃ ] of the thermistor (202), measures and records resonance output wavelength data generated by the range-increasing displacement mechanism (204) under ST different control temperature conditions under the excitation condition of N driving pulse signals respectively, and transfers to the step 117;
step 117: after the resonance output wavelength data automatic test is completed, the control computer (7) reads resonance output wavelength distribution data WT [ 1-N ] [ T1] [ 1-ST ], and the process goes to step 118;
step 118: analyzing the resonance output wavelength distribution data WT [ 1-N ] [ T1] [ 1-ST ] to obtain a tuning wavelength and control temperature distribution trace WTE, and analyzing the distribution trace WTE to obtain an optimal working control temperature point T_OP, wherein the specific steps are shown in step 401 and the step 119 is carried out; the analysis of the resonant output wavelength distribution data to obtain the tuned wavelength and control temperature distribution trace refers to the construction of a two-dimensional plane curve of the position points corresponding to the control temperature (horizontal axis) and the optical wavelength (vertical axis) of the extracted resonant output wavelength distribution data when different driving pulses are loaded to the extended range displacement mechanism, so as to obtain the tuned wavelength and control temperature distribution trace.
Step 119: and outputting the optimal working point W_OP [ DC_OP, T_OP ] of the sweep frequency source of the expansion cavity.
In this embodiment, the calculation flow of the minimum driving current DCmin allowed to be loaded by the full-band output of the extended cavity sweep source is shown in fig. 3, and the distribution data of the laser power and the injection current of the tail fiber of the extended cavity sweep source are rapidly analyzed, so as to obtain distribution traces P1-M and P N1-M, which specifically include the following steps:
step 201: reading the spread cavity sweep source tail fiber laser power and injection current distribution trace P1-M and P N1-M, and turning to step 202;
step 202: calculating the initial current of the self-irradiation power and the injection current distribution traces P1 [1] [ 1-M ] and the first irradiation power P1 [1] [1] [1] backward point by point, namely P1 [ i+1 ]/P1 ] [ i ] [ i ], wherein i=1-M, if the ratio of the n0 th point is larger than a judgment threshold value ThD0 (the typical threshold value is 3), stopping operation, outputting a current value DC0, and turning to step 203;
step 203: calculating the initial current of the self-irradiation power and the injection current distribution trace P [ N ] [ 1-M ] and the first laser power P [1] [1] [1] backward point by point, wherein P [1] [ j+1]/P [1] [ j ] [ j ], j=1-M, if the ratio of the N1 th point is larger than a judgment threshold value ThD1 (the typical threshold value is 3), stopping operation, outputting a current value DC1, and turning to step 204;
step 204: reading current values DC0 and DC1, calculating a difference value DC01 of DC0-DC1, if the difference value DC01 is larger than or equal to 0, outputting a minimum driving current Dcmin=D0 which is allowed to be loaded by the full-band output of the extension cavity frequency sweep source, otherwise, outputting the minimum driving current Dcmin=D1 which is allowed to be loaded by the full-band output of the extension cavity frequency sweep source, and turning to step 205;
step 205: the minimum drive current Dcmin allowed to be loaded is output by the full-band of the extended cavity sweep source.
In this embodiment, the original resonant output wavelength distribution data is automatically analyzed, and the obtained tuning wavelength and tolerance current distribution trace are processed to obtain an optimal working current point dc_op, where a calculation flow of the optimal working current point is shown in fig. 4, and specific steps are as follows:
step 301: reading original resonance output wavelength distribution data W [ 1-N ] [ DCmin+100 mA-M ], and transferring to step 302;
step 302: converting the original resonance output wavelength distribution data into frequency domain data Fre=c/W [ 1-N ] [ DCmin+100 mA-M ], wherein c is the light velocity in vacuum, and turning to step 303;
step 303: calculating difference values DF [ ii ] =Fre [ k+1] -Fre [ k ], ii=1-N, k=DCmin+100 mA-M of two adjacent points of resonant frequency under the excitation of N driving pulse signals by the extended-range displacement mechanism (204), and transferring to step 304;
step 304: finding the driving current point with DF [ ii ] > 0, recording the current DC [ k ] and DC [ k+1] driving current points, and turning to step 305;
step 305: setting the current value outside the tolerance currents FL_ 1[1-N corresponding to the two points of DC [ k+1] and DC [ k ] in the driving current of DC [ DCmin+100 mA-M ] of the extended range displacement mechanism (204) to 0 under the excitation condition of N driving pulse signals respectively, and turning to step 306;
step 306: combining the tolerance current FL_ 1[1-N ] distribution data into full-band tolerance current FL_Q, calculating a difference sequence DC_DF of DC [ DCmin+100 mA-M ] and FL_Q, and turning to step 307, wherein the maximum value max (DC_DF) in DC_DF is equal to the optimal working current point DC_OP;
step 307: and outputting an optimal operation current point DC_OP.
In this embodiment, the original resonant output wavelength distribution data is automatically analyzed, and the obtained tuning wavelength and control temperature distribution trace are processed to obtain an optimal working control temperature point t_op, where a calculation flow of the optimal working control temperature point is shown in fig. 5, and specific steps are as follows:
step 401: reading original resonance output wavelength distribution data WT [ 1-N ] [ T1] [ 1-ST ], and turning to step 402;
step 402: converting the original resonant output wavelength distribution data into frequency domain data Fre1=c/WT [ 1-N ] [ T1] [ 1-ST ], c being the speed of light in vacuum, and turning to step 403;
step 403: calculating the difference DF [ iii ] =Fre [ kk+1] -Fre [ kk ], iii=1-N, kk=RT-2-RT+2 ℃ of two adjacent points under the excitation of N driving pulse signals by the extended-range displacement mechanism (204), and transferring to step 404;
step 404: finding the control temperature point with DF [ iii ] more than 0, recording the current control temperature points of DC [ kk ] and DC [ kk+1], and turning to step 405;
step 405: setting control temperature values outside tolerance temperatures FL_ 2[1-N corresponding to two points of DC [ kk+1] and DC [ kk ] in control temperatures of RT-2-RT+2deg.C under the excitation of N driving pulse signals to 0 by the extended-range displacement mechanism (204), and turning to step 406;
step 406: combining the tolerance temperature FL_ 2[1-N ] distribution data into full-band tolerance temperature FL_Q1, calculating a difference sequence T1_DF between T1 and FL_Q1, and turning to step 407, wherein the maximum value max (T1_DF) in the T1_DF is equal to the optimal working temperature point T_OP;
step 407: and outputting an optimal working temperature point T_OP.
According to the automatic test method for the optimal working point of the extension cavity sweep frequency source, based on the characteristic that a gain seed source used by the sweep frequency source is easily influenced by injection current and environmental temperature fluctuation, through deep analysis of test traces such as extension cavity sweep frequency source tail fiber lasing power, injection current, tuning wavelength, tolerance current, tuning wavelength, control temperature and the like, automatic analysis of the characteristic parameters of the working point of the extension cavity resonance unit is achieved, so that distribution data of intrinsic working parameters of single-tube gain seed sources of different batches and different packaging processes are obtained, efficient and high-accuracy test of the optimal working point characteristic parameters of the extension cavity resonance unit is achieved, and on the basis of the distribution data, wide tuning extension cavity continuous laser output without mode jump suppression is obtained, so that the problems that a traditional on-chip test system is complex in the calibration process of the single-tube gain seed source characteristic working parameter, the whole test system is complex in structure, and the test of the working parameters of the extension cavity resonance unit cannot effectively represent compatibility of the sweep frequency source system, so that the output index performance difference of the extension cavity resonance unit is large are caused; on the other hand, the problems of low efficiency, complex structure and algorithm in the whole machine assembly and debugging process of the continuous sweep frequency source of the extension cavity, which are caused by the technologies of cavity mode monitoring, phase mixing compensation and the like of the traditional hybrid integrated extension cavity sweep frequency source, are solved, an advanced test instrument is provided for the fields of intelligent high-speed coherent network reconfigurable transmission, optical fiber three-dimensional shape frequency domain sensing, high-precision gas spectrum measurement, automatic driving and the like, the application range of the continuous sweep frequency source of the extension cavity without a mode jump is further expanded, the application scene is increased for the continuous sweep frequency source of the extension cavity without a mode jump, and the rapid development of the continuous sweep frequency source industry with the extension cavity without a mode jump in a wide range is promoted.
Example two
As shown in fig. 5 and 6, the present embodiment provides an automatic testing system for an optimum operating point of an extended cavity sweep source, which includes:
the expansion cavity sweep frequency source consists of a single-tube gain seed source integrated unit, a damping bearing unit, a control circuit and an optical interface;
a high-precision incubator for simulating the operating environment temperatures that an extended cavity swept source may face;
the program-controlled attenuator is controlled by the control computer and is used for attenuating the resonant laser power of the sweep source of the expansion cavity, so that the optical wavelength meter is ensured to be under the damage threshold working state in real time;
the optical switch is controlled by the control computer and is used for switching optical signal output channels of the optical power meter and the optical wavelength meter;
the optical power meter is used for extracting the resonant optical power of the gain chip under different injection currents;
an optical wavelength meter for recording of the lasing wavelength;
the control computer provides instruction initialization and driving signals of the control circuit, temperature regulation signals of the high-precision incubator, attenuation gear initialization and attenuation gear switching of the program-controlled attenuator, instruction initialization of the optical switch, test channel switching and synchronous triggering acquisition signals of the optical power meter and the optical wavelength meter, and the control computer receives and processes resonance power and lasing wavelength distribution data information recorded in real time in the optical power meter and the optical wavelength meter.
The single-tube gain seed source integrated unit mainly comprises a gain chip, a thermistor, a thermo-electric refrigerator, a range-extending displacement mechanism and a gold wire bonding connecting wire;
the gain chip is used for generating a free space optical external cavity strong feedback seed source; the said
The thermistor is used for monitoring and feeding back the junction temperature of the gain chip;
the thermo-electric refrigerator is used for temperature field adjustment;
the range-extending displacement mechanism is a stepping motor integrated with piezoelectric ceramics and is used for controllably tuning the cavity length of the expansion cavity sweep frequency source;
the gold wire bonding connection wire is used for electric connection.
The damping bearing unit is used for bearing the sweep frequency source of the expansion cavity and reducing damping;
the control circuit is controlled by the control computer and used for loading the driving current of the single-tube gain seed source integrated unit;
the optical interface is used for guiding out the sweep frequency laser signals.
According to the automatic test method for the optimal working point of the extension cavity sweep frequency source, the automatic analysis of the characteristic parameters of the working point of the extension cavity resonance unit is realized through the deep analysis of test traces such as the extension cavity sweep frequency source tail fiber lasing power and injection current, the tuning wavelength and tolerance current, the tuning wavelength and control temperature, and the like, so that the distribution data of the intrinsic working parameters of single-tube gain seed source integrated units of different batches and different packaging processes are obtained, the efficient and high-accuracy test of the characteristic parameters of the optimal working point of the extension cavity resonance unit is realized, the wide tuning extension cavity continuous laser output without mode jump inhibition is obtained on the basis of the distribution data, the structure of an automatic test system for the optimal working point of a typical extension cavity sweep frequency source is shown in a figure 6, and the composition is as follows:
(1) The expansion cavity sweep frequency source mainly comprises a single-tube gain seed source integrated unit (101), a damping bearing unit (102), a control circuit (103), an optical interface (104) and the like, and is shown in fig. 2.
(2) The high-precision incubator is used for simulating the working environment temperature possibly faced by an expansion cavity sweep frequency source, the typical temperature adjustment precision is +/-1 ℃, and the typical temperature setting range is 10-35 ℃.
(3) The program-controlled attenuator is controlled by the control computer (7) and is used for attenuating the resonant lasing light power of the expansion cavity sweep frequency source (1) so as to ensure that the optical wavelength meter (6) is in a damage threshold working state in real time.
(4) The 1X 2 optical switch is controlled by the control computer (7) to switch the optical signal output channels of the optical power meter (5) and the optical wavelength meter (6).
(5) The optical power meter is used for extracting the resonant optical power of the gain chip under different injection currents.
(6) Optical wavelength meter for recording the lasing wavelength.
(7) The control computer provides instruction initialization and driving signals of a control circuit (103) in the expansion cavity sweep frequency source, temperature regulation signals of the high-precision incubator (2), attenuation gear initialization and attenuation gear switching of the program-controlled attenuator (3), instruction initialization and test channel switching of the optical switch (4), synchronous triggering acquisition signals of the optical power meter (5) and the optical wavelength meter (6), and distributed data information such as resonance power, lasing wavelength and the like recorded in real time in the optical power meter (5) and the optical wavelength meter (6) are received and processed.
As shown in fig. 7, an exemplary embodiment of an automatic test of an optimum working point of an extended cavity sweep source is implemented by further analyzing test traces such as an extended cavity sweep source tail fiber lasing power and injection current, a tuning wavelength and tolerance current, and a tuning wavelength and a control temperature, so as to automatically analyze characteristic parameters of the extended cavity resonant unit, obtain distribution data of intrinsic working parameters of single-tube gain seed source integrated units of different batches and different packaging processes, and implement an efficient and high-accuracy test of the optimum working point characteristic parameters of the extended cavity resonant unit, and the specific composition is as follows:
as shown in fig. 8, (101) a single tube gain seed source integrated unit is mainly composed of a gain chip (201), a thermistor (202), a thermo-electric refrigerator (203), a range-extending displacement mechanism (204), a gold wire bonding connection wire (205) and the like. The gain chip (201) is typically an InP-based single-angle-degree semiconductor gain chip, the typical value of the single-angle-degree reflectivity is 0.005%, the typical value of the 3dB bandwidth is better than 80nm, and the gain chip is used for generating a free space optical external cavity strong feedback seed source; the thermistor (202) is typically controlled to be 25 ℃ (10 kΩ) and is used for monitoring and feedback of the junction temperature of the gain chip; a thermo-electric refrigerator (203) for temperature field conditioning; the extended range displacement mechanism (204) is typically a stepping motor integrated with piezoelectric ceramics and is used for controllably tuning the cavity length of the extended cavity sweep source; the gold wire bond wire (205) is used for electrical connection.
(102) And the damping bearing unit is used for bearing the expansion cavity sweep frequency source and reducing damping.
(103) The control circuit is controlled by the control computer (7) and is used for driving current loading of the single-tube gain seed source integrated unit (101).
(104) The optical interface, generally FC/APC interface, is used for guiding out the sweep laser signal.
While the foregoing description of the embodiments of the present invention has been presented in conjunction with the drawings, it should be understood that it is not intended to limit the scope of the invention, but rather, it is intended to cover all modifications or variations within the scope of the invention as defined by the claims of the present invention.
Claims (10)
1. An automatic testing method for an optimal working point of an expansion cavity sweep frequency source is characterized by comprising the following steps:
obtaining distribution trajectories of the tail fiber laser power and the injection current of the sweep source of the expansion cavity by testing distribution data of the resonant output optical power under different driving currents, and analyzing the distribution trajectories of the tail fiber laser power and the injection current of the sweep source of the expansion cavity to determine the maximum output power and the minimum driving current of the sweep source of the expansion cavity;
the maximum output power and the minimum driving current of the extended cavity sweep frequency source are used as limiting values, the distribution data of the resonant output wavelength under a single driving current are tested to obtain a distribution track line of the tuning wavelength and the tolerance current, and the distribution track line of the tuning wavelength and the tolerance current is analyzed to determine an optimal working current point;
obtaining a part track line of the tuning wavelength and the control temperature by testing resonance output wavelength distribution data under different control temperatures, and analyzing the tuning wavelength and the control temperature distribution track line to determine an optimal working control temperature point;
and forming an optimal working point of the expansion cavity sweep frequency source based on the optimal working current point and the optimal working control temperature point, and outputting the optimal working point.
2. The automatic testing method for the optimum operating point of the swept source of the extended cavity according to claim 1, wherein the distribution trace line of the laser power and the injection current of the tail fiber of the swept source of the extended cavity is obtained by testing the distribution data of the resonant output optical power under different driving currents, specifically:
respectively loading driving currents DC 1-M into gain chips in a single-tube gain seed source integrated unit in the expansion cavity sweep source, and measuring and recording resonance output optical power data generated by M driving currents under the excitation condition of N driving pulse signals by an extended range displacement mechanism in the expansion cavity sweep source;
after the resonance output light power data is automatically tested, reading resonance output light power distribution data P [ 1-N ] [ 1-M ];
analyzing the resonant output light power distribution data P1-N1-M to obtain the distribution trace lines P1-M, P C1-M and P N1-M of the spread cavity sweep frequency source tail fiber laser power and injection current, wherein when N is odd number, C= (N+1)/2, and when N is even number, C=N/2.
3. The automatic test method for the optimal operating point of the extended cavity sweep source according to claim 1, wherein the maximum output power and the minimum driving current of the extended cavity sweep source are determined by analyzing the distribution trace of the laser power and the injection current of the tail fiber of the extended cavity sweep source, specifically:
analyzing the distribution trace PC 1-M of the tail fiber laser power and the injection current of the extended cavity sweep source to obtain the maximum output power Pmax of the extended cavity sweep source, wherein Pmax=PC M;
and analyzing distribution traces P1, 1-M and P N, 1-M of the lasing power and injection current of the sweep source of the extension cavity to obtain the minimum driving current DCmin allowed to be loaded by the full-band output of the sweep source of the extension cavity.
4. The method for automatically testing the optimum operating point of the extended cavity swept source according to claim 3, wherein the analysis of the extended cavity swept source tail fiber lasing power and injection current distribution traces P [1] [ 1-M ] and P [ N ] [ 1-M ] is performed to obtain the minimum driving current DCmin allowed to be loaded by the extended cavity swept source full-band output, specifically:
reading distribution traces P1-M and P1-M N1-M of the spread cavity sweep source tail fiber laser power and injection current;
calculating the initial current of the self-irradiation power and injection current distribution traces P1 [1] [ 1-M ] and the first laser power P1 [1] [1] [1] backward point by point, namely P1 [ i+1 ]/P1 ] [ i ] [ i ], wherein i=1-M, and if the ratio of the n0 th point is larger than a judgment threshold value ThD0, stopping operation and outputting a current value DC0;
self-injection power and injection current distribution trace P [ N ]][1～M][1～M]And a first lasing power P1][1][1]Point-by-point calculation of P1][j+1][j+1]/P[1][j][j]J=1 to M, if the ratio of the n1 st point is greater than the determination threshold value ThD1, stopping the operation and outputting the current value DC 1 ；
Reading current values DC0 and DC1, calculating a difference value DC01 of DC0-DC1, if DC01 is more than or equal to 0, outputting a minimum driving current DCmin=DC0 which is allowed to be loaded by the full-band output of the extension cavity frequency sweep source, otherwise, outputting a minimum driving current DCmin=DC1 which is allowed to be loaded by the full-band output of the extension cavity frequency sweep source;
the minimum drive current DCmin allowed to be loaded is output by the full-band of the extended cavity swept source.
5. The automatic test method of the optimum operating point of the extended cavity frequency sweep source according to claim 1, wherein the maximum output power and the minimum driving current of the extended cavity frequency sweep source are used as limiting values, and the tuning wavelength and the tolerance current distribution trace line is obtained by testing the resonance output wavelength distribution data under a single driving current, specifically:
step a: reading a driving pulse signal number C and a driving current number M corresponding to the maximum output power Pmax of the expansion cavity sweep source, and respectively loading the C and the M to gain chips in a range-extending displacement mechanism in the expansion cavity sweep source and a single-tube gain seed source integrated unit in the expansion cavity sweep source;
step b: the control computer adjusts the attenuation gear of the program-controlled attenuator to be added with 1, judges whether the resonance optical power PA collected by the optical power meter is smaller than or equal to a set threshold value, if so, goes to the step d, otherwise goes to the step c;
step c: the control computer adjusts the attenuation gear of the program-controlled attenuator and adds 1, judges whether the resonance optical power PA collected by the optical power meter is smaller than or equal to a set threshold value, if so, the step d is switched to, otherwise, the step c is switched to again;
step d: the control computer places the optical switch at the channel position CP 2, the control circuit in the expansion cavity sweep frequency source loads the gain chip in the single tube gain seed source integrated unit in the expansion cavity sweep frequency source, which loads the driving current DC [ DCmin+100 mA-M ], measures and records the resonance output wavelength data generated by M- (DCmin+100 mA) +1 driving current under the condition of the excitation of N driving pulse signals by the stroke-increasing displacement mechanism in the expansion cavity sweep frequency source, and then transfers to the step e;
step e: after the resonance output wavelength data automatic test is completed, reading resonance output wavelength distribution data W [ 1-N ] [ DCmin+100 mA-M ], and transferring to the step f;
step f: and analyzing the resonant output wavelength distribution data to obtain a tuning wavelength and tolerance current distribution trace WE.
6. The automatic testing method for the optimal operating point of the extended cavity sweep source according to claim 1, wherein the optimal operating current point is determined by analyzing the path line of the modulated wave length and the tolerance current distribution, specifically:
reading original resonant output wavelength distribution data
W[1～N][DCmin+100mA～M][DCmin+100mA～M]；
Converting the original resonance output wavelength distribution data into frequency domain data Fre=c/W [ 1-N ] [ DCmin+100 mA-M ], wherein c is the light speed in vacuum;
calculating the difference value DF [ ii ] =Fre [ k+1] -Fre [ k ], ii=1-N, and k=DCmin+100 mA-M of two adjacent points of resonant frequency under the excitation of N driving pulse signals of an extended cavity sweep source internal extended range displacement mechanism;
searching a driving current point with DF [ ii ] > 0, and recording the current DC [ k ] and DC [ k+1] driving current points;
setting the current value outside the tolerance currents FL_ 1[1-N corresponding to the two points of DC [ k+1] and DC [ k ] in the DC [ DCmin+100 mA-M ] driving current under the excitation of N driving pulse signals of the extension cavity sweep source in an extension range displacement mechanism to be 0;
combining the distribution data of the tolerance currents FL-1[1-N into full-band tolerance current FL-Q, calculating a difference sequence DC-DF of DC [ DCmin+100 mA-M ] and FL-Q, and enabling the maximum value max (DC-DF) in the DC-DF to be equal to the optimal working current point DC-OP;
and outputting an optimal operation current point DC_OP.
7. The automatic testing method for the optimal operating point of the extended cavity swept source according to claim 1, wherein the analysis of the tuned wavelength and the control temperature distribution trace line determines the optimal operating control temperature point, specifically:
reading original resonance output wavelength distribution data WT [ 1-N ] [ T1] [ 1-ST ];
converting the original resonant output wavelength distribution data into frequency domain data Fre1=c/WT [ 1-N ] [ T1] [ 1-ST ], c being the speed of light in vacuum;
calculating the difference value DF [ iii ] =Fre [ kk+1] -Fre [ kk ], iii=1-N, kk=RT-2-RT+2 ℃ of two adjacent points of resonant frequency under the excitation of N driving pulse signals by an extended range displacement mechanism in the extended cavity sweep source;
searching a control temperature point with DF [ iii ] more than 0, and recording the current DC [ kk ] and DC [ kk+1] control temperature points;
setting control temperature values outside tolerance temperatures FL_ 2[1-N corresponding to DC [ kk+1] and DC [ kk ] in control temperatures of RT-2-RT+2deg.C under the excitation of N driving pulse signals of an extension cavity sweep source to 0;
combining the tolerance temperature FL_ 2[1-N ] distribution data into full-band tolerance temperature FL_Q1, calculating a difference sequence T1_DF between T1 and FL_Q1, and enabling the maximum value max (T1_DF) in the T1_DF to be equal to the optimal working temperature point T_OP;
and outputting an optimal working temperature point T_OP.
8. An automatic test system for an optimum operating point of an extended cavity swept source, comprising:
the expansion cavity sweep frequency source consists of a single-tube gain seed source integrated unit, a damping bearing unit, a control circuit and an optical interface;
a high-precision incubator for simulating the operating environment temperatures that an extended cavity swept source may face;
the program-controlled attenuator is controlled by the control computer and is used for attenuating the resonant laser power of the sweep source of the expansion cavity, so that the optical wavelength meter is ensured to be under the damage threshold working state in real time;
the optical switch is controlled by the control computer and is used for switching optical signal output channels of the optical power meter and the optical wavelength meter;
the optical power meter is used for extracting the resonant optical power of the gain chip under different injection currents;
an optical wavelength meter for recording of the lasing wavelength;
the control computer is used for providing instruction initialization and driving signals of the control circuit, temperature regulation signals of the high-precision incubator, attenuation gear initialization and attenuation gear switching of the program-controlled attenuator, instruction initialization and test channel switching of the optical switch, and synchronous triggering acquisition signals of the optical power meter and the optical wavelength meter, and the control computer is used for receiving and processing resonance power and lasing wavelength distribution data information recorded in real time in the optical power meter and the optical wavelength meter.
9. The automatic testing system of an optimum working point of an extended cavity sweep source according to claim 8, wherein the single tube gain seed source integrated unit is mainly composed of a gain chip, a thermistor, a thermo-electric refrigerator, an extended range displacement mechanism and a gold wire bonding connecting wire;
the gain chip is used for generating a free space optical external cavity strong feedback seed source; the said
The thermistor is used for monitoring and feeding back the junction temperature of the gain chip;
the thermo-electric refrigerator is used for temperature field adjustment;
the range-extending displacement mechanism is a stepping motor integrated with piezoelectric ceramics and is used for controllably tuning the cavity length of the expansion cavity sweep frequency source;
the gold wire bonding connection wire is used for electric connection.
10. The automatic test system of claim 8, wherein the shock absorbing bearing unit is used for bearing the expansion cavity sweep frequency source and reducing damping;
the control circuit is controlled by the control computer and used for loading the driving current of the single-tube gain seed source integrated unit;
the optical interface is used for guiding out the sweep frequency laser signals.
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