CN106877170B - Laser emission automatic control circuit, method and related chip, optical module and equipment - Google Patents
Laser emission automatic control circuit, method and related chip, optical module and equipment Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
- H01S5/042—Electrical excitation ; Circuits therefor
- H01S5/0427—Electrical excitation ; Circuits therefor for applying modulation to the laser
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Abstract
The invention discloses a laser emission automatic control circuit, a laser emission automatic control method, a related chip, an optical module and equipment. The circuit comprises: an inner loop control circuit and an outer loop control circuit; the inner loop control circuit is used for generating bias current according to feedback of the emitted laser and preset power current control parameters; coupling the bias current and the modulation current output by the outer ring control circuit and then applying the coupled bias current and the modulation current to the emitted laser; the outer loop control circuit is used for outputting a modulation current controlled by a proportion according to a preset laser aging parameter and a bias current value of the inner loop control circuit; the invention adopts the double control loops, the inner loop control circuit uses the bias current controlled by the average power to control the average power of the laser, the outer loop control circuit adopts the modulation current controlled by the proportion to realize the purpose of stabilizing the extinction ratio, and the coefficient controlled by the proportion is related to the equivalent modulation proportion coefficient, the current coupling coefficient of the modulation current and the bias current and the modulation baseline lifting coefficient, so that the control precision is higher.
Description
Technical Field
The present invention relates to the field of optical communications technologies, and in particular, to a laser emission automatic control circuit, a laser emission automatic control method, and a related chip, optical module, and device.
Background
In optical communications, the optical transmitting end is a device in optical communications that includes an optical module or an optical transceiver unit, such as a laser, capable of converting an electrical signal into an optical signal and efficiently coupling the optical signal to a transmission fiber.
The average light power and extinction ratio of the working output of the laser are two important indexes, but due to the nonlinearity of the laser, the dispersion of the luminous efficiency of the laser, the change and variation of the factors such as temperature, aging and the like, the average light power and extinction ratio emitted by the laser can be changed, so that the stable average light power and extinction ratio parameters are the key points of automatic control of the light emitting end.
The average optical power and extinction ratio of the laser under direct intensity modulation are determined by the bias current and modulation current provided by the laser diode driver chip. The optical transmitting terminal is required to maintain stable extinction ratio of the optical signal as far as possible in addition to stable optical signal power output in the full temperature range and under the aging condition of the device. Generally, the extinction ratio is too small, the proportion of the modulated optical signal power in the signal power is reduced, the receiving sensitivity of the optical receiving end is poor, when the extinction ratio is too large, the light emitting device is often caused to work in a nonlinear region, so that the optical emission output eye pattern is deteriorated, and finally the optical receiving sensitivity is deteriorated, so that the control of the extinction ratio should be maintained within a reasonable range, and the optical receiving sensitivity can be optimized. In actual production, because of the differences of the circuit parameters and the working temperature of the chip and the laser, the extinction ratio is difficult to precisely control and can only be controlled within a certain reasonable range. However, the change of the environment working temperature or the aging of the device can cause the change of the circuit original parameters, influence the change of the extinction ratio, cause the sensitivity to be deteriorated and cause the rapid increase of the error rate, so that the maintenance of the extinction ratio stability in long-term working has great significance for the communication quality of optical communication.
When the parameters of the light emitting end are controlled at present, for stabilizing the light power of the laser, a single closed loop scheme is often adopted to control the average light power, but the circuit cannot reach the condition of stabilizing the extinction ratio.
For the manner of controlling the extinction ratio, the method is generally based on an open loop operation mode, for example, the following methods:
1. the thermistor compensation circuit is designed according to the temperature characteristic of the laser.
The linearity of the thermistor and the difference in compensation curves, as well as the difference in temperature measurement points, make this compensation limited.
2. By using the K-factor compensation method, the modulation current is proportionally increased while the laser bias current is increased, provided that the "K-factor" compensation characteristic is adopted in the driver of the laser.
The scheme has single parameter control and can not fully reflect the influence effect of the bias current on the modulation current.
The thermistor compensation method and the K-factor compensation method are different in implementation modes, but basically utilize open loop control to stabilize the extinction ratio, and the methods have the advantages of being simple in implementation, enabling the extinction ratio to be stabilized in a certain range, and have the disadvantages that the extinction ratio is also changed depending on the consistency of a laser device, and the compensation effect is limited.
The average light power of the light emitting end is stabilized, the extinction ratio is stabilized at the same time, and the light emitting circuit of the traditional light module still cannot be well controlled.
Disclosure of Invention
The present invention has been made in view of the above problems, and it is an object of the present invention to provide a laser emission automatic control circuit, a method and a related chip, optical module and device which overcome or at least partially solve the above problems.
In a first aspect, an embodiment of the present invention provides a laser emission automatic control circuit, including: an inner loop control circuit and an outer loop control circuit;
the inner loop control circuit is used for generating bias current controlled by average power according to feedback of the emitted laser and preset power current control parameters; coupling the bias current with the modulation current output by the outer ring control circuit and then applying the coupled bias current and the modulation current to the emitted laser;
the outer loop control circuit is used for outputting modulation current with proportion control according to preset laser aging parameters and bias current values of the inner loop control circuit.
In one embodiment, the inner loop control circuit includes: the laser detection device comprises a laser emission circuit, a detection filter circuit, a first subtracter, an integral control circuit, a bias current driving circuit and a current coupling circuit which are sequentially connected and form a closed loop; the outer loop control circuit includes: the second subtracter, the proportional control circuit and the modulation current driving circuit are connected in sequence;
wherein: the output end of the laser emission circuit is connected with the input end of the detection filter circuit; the output end of the detection filter circuit is connected with the negative electrode input end of the first subtracter, and the positive electrode input end of the first subtracter is used for inputting preset power current control parameters; the output end of the first subtracter is connected with the input end of the integration control circuit; the output end of the integral control circuit is respectively connected with the input end of the bias current driving circuit and the negative electrode input end of the second subtracter; the output end of the bias current driving circuit is connected with the input end of the current coupling circuit;
the positive electrode input end of the second subtracter is used for inputting the ageing parameters of the laser; the output end of the second subtracter is connected with the input end of the proportional control circuit; the output end of the proportional control circuit is connected with the input end of the modulation current driving circuit, and the output end of the modulation current driving circuit is connected with the input end of the current coupling circuit;
the modulation current I output by the modulation current driving circuit m And a bias current I output by the bias current driving circuit d The method meets the following conditions: i m ＝E*(I d -I'); the I' is a laser aging parameter;
the control coefficient E= (1-Z)/(ZK-A) of the proportional control circuit, wherein Z is an equivalent modulation proportional coefficient, K is A current coupling coefficient of the modulation current and the bias current in the current coupling circuit, and A is A modulation baseline lifting coefficient.
In one embodiment, the coupling mode of the current coupling circuit includes: a direct current coupling mode and an alternating current coupling mode.
In one embodiment, in the dc coupling mode:
I d +K*I m ＝I 1
I d +AI m ＝I 0
in the ac coupling mode:
I d +K/2*I m ＝I 1
I d +(A-K/2)I m ＝I 0 ；
in the above, I m A modulation current output by the modulation current driving circuit; i d A bias current output from the bias current driving circuit;
k is a current coupling coefficient of the modulation current and the bias current in the current coupling circuit;
a is a modulation baseline lifting coefficient;
I 1 is the current at the laser '1' level;
I 0 is the current at the laser "0" level.
In one embodiment, the detection filter circuit includes: a backlight signal detection circuit and a low-pass filter;
the output end of the laser emission circuit is connected with the input end of the backlight signal detection circuit;
the output end of the backlight signal detection circuit is connected with the input end of the low-pass filter;
the output end of the low-pass filter is connected with the negative electrode input end of the first subtracter.
In one embodiment, the integral control circuit includes: an integral controller, a bias current register and a bias current digital-to-analog converter which are connected in sequence; wherein:
the output end of the first subtracter is connected with the input end of the integration controller;
the output end of the bias current register is respectively connected with the negative electrode input end of the second subtracter and the input end of the bias current digital-to-analog converter;
the output end of the bias current digital-to-analog converter is connected with the input end of the bias current driving circuit.
In one embodiment, the ratio control circuit includes: the system comprises a proportional controller, a modulation current register and a modulation current digital-to-analog converter; wherein:
the output end of the second subtracter is connected with the input end of the proportional controller, and the proportional controller also comprises the input end of the control coefficient E; the output end of the proportional controller is connected with the input end of the modulation current register;
the output end of the modulation current register is connected with the input end of the modulation current digital-to-analog converter;
the output end of the modulation current digital-to-analog converter is connected with the input end of the modulation current driving circuit.
In one embodiment, the positive input terminal of the first subtracter is also connected with a digital-to-analog converter.
In a second aspect, an embodiment of the present invention provides a chip, where the chip includes the laser emission automatic control circuit described above.
In a third aspect, an embodiment of the present invention provides an optical module, where the optical module includes the above-mentioned laser emission automatic control circuit.
In a fourth aspect, an embodiment of the present invention further provides a laser emission automatic control method, including:
generating bias current controlled by average power according to feedback of the emitted laser and preset power current control parameters;
outputting a proportional controlled modulation current according to a preset laser aging parameter and the bias current value;
the bias current and the modulation current are coupled and then applied to the emitted laser light.
In one embodiment, generating a bias current controlled with average power based on feedback of the emitted laser light and a preset power current control parameter includes:
detecting and low-pass filtering the feedback signal of the emitted laser, and then subtracting with a preset power current control parameter;
integrating the result obtained by the subtraction operation to obtain a bias current value;
and outputting corresponding bias current according to the bias current value.
In one embodiment, outputting a proportionally controlled modulation current according to a preset laser aging parameter and a bias current value of the inner loop control circuit comprises:
subtracting a preset aging coefficient of the laser from a bias current value;
multiplying the result obtained by subtraction operation by a preset control coefficient E to obtain a modulation current value;
outputting a corresponding modulation current according to the modulation current value;
the control coefficient E= (1-Z)/(ZK-A)), wherein Z is an equivalent modulation proportion coefficient, K is A current coupling coefficient of the modulation current and the bias current, and A is A modulation baseline lifting coefficient.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
the embodiment of the invention provides an automatic control circuit and method for laser emission, and a related chip, an optical module and equipment, wherein a double control loop is adopted, the double control loop comprises an inner loop control circuit and an outer loop control circuit, and the inner loop control circuit is used for generating bias current controlled by average power according to feedback of emitted laser and preset power current control parameters; the bias current is coupled with the modulation current output by the outer loop control circuit and then applied to the emitted laser, and the outer loop control circuit is used for outputting the modulation current with proportion control according to the preset laser aging parameter and the bias current value of the inner loop control circuit; the inner loop control circuit outputs bias current controlled by average power, the outer loop control circuit outputs modulation current after proportional control according to laser aging coefficient, the modulation current and the bias current are coupled according to a certain proportion and are applied to emitted laser, so that the bias current controlled by average power is used for controlling the average power of the laser, and the purpose of stabilizing extinction ratio is achieved by the modulation current controlled by proportion.
And the proportional control coefficient of the outer loop control circuit is related to the equivalent modulation proportional coefficient, the current coupling coefficient of the modulation current and the bias current and the modulation baseline lifting coefficient, so that the control precision is higher.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:
fig. 1 is a schematic structural diagram of an automatic laser emission control circuit according to an embodiment of the present invention;
FIG. 2 is a graph of photo-electric conversion power versus current for a laser at different temperatures according to an embodiment of the present invention;
FIG. 3 is a simplified graph of the photo-electric conversion power versus current curve of a laser at different temperatures according to an embodiment of the present invention;
FIG. 4 is a diagram of a coupling model of a current coupling circuit using DC-DC coupling according to an embodiment of the present invention;
FIG. 5 is a diagram of a coupling model of a current coupling circuit using DC-AC coupling according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of another embodiment of the automatic laser emission control circuit according to the present invention;
FIG. 7 is a flowchart of a method for automatically controlling laser emission according to an embodiment of the present invention;
FIG. 8 is a flowchart of the implementation of step S701 according to an embodiment of the present invention;
fig. 9 is a flowchart of step S702 according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In order to illustrate the technical scheme of the invention, the following description is made by specific examples.
The embodiment of the invention provides a laser emission automatic control circuit, which comprises: an inner loop control circuit and an outer loop control circuit; wherein:
the inner loop control circuit is used for generating bias current controlled by average power according to feedback of the emitted laser and preset power current control parameters; coupling the bias current with the modulation current output by the outer ring control circuit and then applying the coupled bias current and the modulation current to the emitted laser;
the outer loop control circuit is used for outputting modulation current with proportion control according to preset laser aging parameters and bias current values of the inner loop control circuit.
The laser emission automatic control circuit provided by the embodiment of the invention adopts a double control loop, and comprises an inner loop control circuit and an outer loop control circuit, wherein the inner loop control circuit outputs bias current controlled by average power, the outer loop control circuit outputs modulation current after being subjected to proportional control according to laser aging coefficient output, the modulation current and the bias current are coupled according to a certain proportion and are applied to emitted laser, so that the control of the average power of the laser is realized by adopting the bias current controlled by average power, and the purpose of stabilizing extinction ratio is realized by adopting the modulation current controlled by proportion.
In one embodiment, the laser emission automatic control circuit provided by the embodiment of the invention comprises: an inner loop control circuit and an outer loop control circuit; as shown in fig. 1, the inner loop control circuit includes: a laser emitting circuit 1, a detection filter circuit 2, a first subtracter 3, an integration control circuit 4, a bias current driving circuit 5 and a current coupling circuit 9 which are connected in sequence and form a closed loop; an outer loop control circuit comprising: a second subtracter 6, a proportional control circuit 7 and a modulation current driving circuit 8 which are connected in sequence;
wherein: the output end of the laser emission circuit 1 is connected with the input end of the detection filter circuit 2; the output end of the detection filter circuit 2 is connected with the negative electrode input end of the first subtracter 3, and the positive electrode input end of the first subtracter 3 is used for inputting preset power current control parameters; the output end of the first subtracter 3 is connected with the input end of the integration control circuit 4; the output end of the integration control circuit 4 is respectively connected with the input end of the bias current driving circuit 5 and the negative electrode input end of the second subtracter 6; the output end of the bias current driving circuit 5 is connected with the input end of the current coupling circuit 9;
the positive electrode input end of the second subtracter 6 is used for inputting the ageing parameters of the laser; the output end of the second subtracter 6 is connected with the input end of the proportional control circuit 7; the output end of the proportional control circuit 7 is connected with the input end of the modulation current driving circuit 8, and the output end of the modulation current driving circuit 8 is connected with the input end of the current coupling circuit 9;
modulation current I output from modulation current driving circuit 8 m And bias current I output from bias current driving circuit 5 d The method meets the following conditions: i m ＝E*(I d -I'); i' is the ageing parameter of the laser;
control coefficient e= (1-Z)/(ZK-A)) of the proportional control circuit 7, where Z is an equivalent modulation proportional coefficient, K is A current coupling coefficient of the modulation current and the bias current in the current coupling circuit 9, and A is A modulation baseline lifting coefficient.
The optical signal output by the laser emitting circuit 1 is input to the cathode of the first subtracter 3 after passing through the detection filter circuit 2, and the anode of the first subtracter 3 is used for inputting the power current control parameter I B The output end of the first subtracter 3 outputs a bias current value I after passing through an integral control circuit 4 m The bias current value is input to the bias current driving circuit 5 on one hand and is input to the negative electrode of the second subtracter 6 on the other hand, the positive electrode of the second subtracter 6 is used for inputting the aging coefficient I', and the output end of the second subtracter 6 outputs the modulation current value I after passing through the proportional control circuit 7 d Modulation current value I d Is input to a modulation current driving circuit 8, and a current signal output by the bias current driving circuit 5 and the modulation current driving circuit 8 is processed by a current coupling circuit 9 and then is input to the laser emitting circuit 1.
If the output average power and extinction ratio parameters of the light emitting end of the laser are required to be stabilized in the control range of the index, the bias current and the modulation current must be modulated and controlled. The laser emission automatic control circuit provided by the embodiment of the invention comprises an inner loop control circuit and an outer loop control circuit, wherein the inner loop control circuit controls the average power of the laser by using the bias current controlled by the average power, the outer loop control circuit adopts the modulation current controlled by the proportion to realize the purpose of stabilizing the extinction ratio, and the coefficient controlled by the proportion is related to the equivalent modulation proportion coefficient, the current coupling coefficient of the modulation current and the bias current and the modulation baseline lifting coefficient, so that the control precision is higher.
In one embodiment, the inner loop control circuit may adopt an advanced control system (Advanced Process Control, APC) control mode, after the detection and filtering circuit 2 performs backlight detection and filtering, the comparison result output by the first subtractor 3 is compared with a preset power current control parameter, and the comparison result is output by the integral control circuit 4 and a bias current value, and then the bias current of the laser is adjusted by controlling the current control end of the bias current driving circuit 5, and is applied to the laser emitting circuit 1 through the current coupling circuit 9, so as to keep the average light power stable.
In one embodiment, the outer loop control circuit may use ER control, subtract the aging coefficient of the laser from the bias current value in the inner loop control circuit, multiply the subtracted result with the control coefficient E to obtain a modulation current value, then adjust the modulation current of the laser by controlling the current control terminal of the modulation current driving circuit 8, and apply the bias current and the modulation current to the laser emitting circuit 1 through the current coupling circuit 9.
In the embodiment of the invention, the aging coefficient I' is a parameter describing the trend of the laser in the aging process, and the modulation baseline lifting coefficient A is a parameter used for describing the effect of modulation current on bias baseline lifting under different coupling (DC or AC modes); the current coupling coefficient K is a parameter for describing the coupling efficiency of the modulation current and the bias current in the coupling circuit; the equivalent modulation scaling factor Z is introduced in order to obtain the parameters required for extinction ratio.
The equivalent modulation ratio coefficient Z and the aging coefficient I' are parameters related to the aging of the device or the temperature change, when the temperature changes, the photoelectric conversion efficiency changes, and the bias current I is adjusted d The optical power is kept unchanged, so I d And will also vary. Embodiments of the inventionThe main point is the modulation current I m Control is carried out, in general I 0 The ("current at" 0 "level) is unknown, and a method needs to be found here to determine I at different temperatures 0 Thus, I at different temperatures can be calculated 1 The current at the level of '1' is used for achieving the purpose of adjusting the extinction ratio.
As shown in fig. 2, the P-I curves of the lasers at different temperatures intersect at a point N under two extreme conditions (e.g., industrial temperature conditions-40 ℃ and +85 ℃) and the point N corresponds to the optical power P 'and the current I' on the P-I curve, and the P-I curves also converge at the intersection point at other operating temperatures. As shown in the following graph, the P-I curve intersects at point N at +25℃. Referring to the simplified power current curve shown in FIG. 3, assume P at-40℃ 0 Corresponding current is I 0 P at +85℃ 0 Corresponding current is I 0 'A'; p at 40 DEG C 1 Corresponding current is I 1 P at +85℃ 1 Corresponding current is I 1 ' wherein P 0 Optical power at "0" level, P 1 Optical power at "1" level. From the theorem that the corresponding sides of similar triangles are proportional:
Z＝(I 0 -I’)/(I 1 -I’)＝(I 0 ’-I’)/(I 1 ’-I’) (1)
the method comprises the following steps:
I’＝(I 0 I 1 ’-I 1 I 0 ’)/[(I 1 ’-I 0 ’)-(I 1 -I 0 )] (2)
namely:
I 0 ’＝I 1 ’-(1-Z)(I 1 ’-I’) (3)
I 0 ＝I 1 -(1-Z)(I 1 -I’) (4)
for the current coupling circuit, a direct current DC coupling or alternating current AC coupling mode can be adopted, feedback and adjustment speed is low under AC coupling, parameters are not easy to match, power consumption of a driver is large, output modulation current is large, DC coupling is free of low speed limit, matching is easy, high-speed performance is good, power consumption is low, and output modulation current is small. The present embodiment is not limited to DC coupling or AC coupling, and since the bases of the modulation current and bias current coupling are different, a current coupling coefficient K is set in the embodiment of the present invention to reflect the coupling efficiency.
The influence of the modulation current on the bias current under different coupling modes is considered to introduce a current coupling coefficient K, and the effect of the modulation current on the bias baseline lifting is considered to introduce a modulation baseline lifting coefficient A. Referring to the DC coupling model and the AC coupling model shown in FIGS. 4 and 5, the current and bias current flows and I are modulated at this time 0 、I 1 The relation between the two is:
under DC coupling conditions:
I d +K*I m ＝I 1 (7)
I d +AI m ＝I 0 (8)
under AC coupling conditions:
I d +K/2*I m ＝I 1 (7’)
I d +(A-K/2)I m ＝I 0 (8’)
because the DC coupling and the AC coupling are only different in proportion parameters, the relationship between the current coupling coefficient K 'and the modulation baseline lifting coefficient A' under the AC condition and the current coupling coefficient K modulation baseline lifting coefficient A under the DC coupling condition accords with the following formula: k '=k/2, and the baseline lift coefficient a' =a-K/2 is modulated, so that the two can be unified on the DC coupling model, and only the positive and negative of a are unstable at this time.
According to the above (4), (7) and (8), I is obtained m The expression relationship is:
I m ＝(1-Z)/(ZK-A)*(I d -I’)
in the above formulA, let E= (1-Z)/(ZK-A)), i.e. I m ＝E*(I d -I’)，I d Is the current bias current value, I', Z, K, A are all known parameters, so the current I can be determined m Is a value of (2). I m The average light power will be affected after updating, at this time the inner loop control circuit will lock a new I d Value to reach equilibriumThe ideal modulation current and bias current are obtained.
In one embodiment, as shown in fig. 6, the detection filter circuit 2 may further include: a backlight signal detection circuit 21 and a low-pass filter 22;
the output end of the laser emission circuit 1 is connected with the input end of the backlight signal detection circuit 21;
an output end of the backlight signal detection circuit 21 is connected with an input end of the low-pass filter 22;
an output of the low pass filter 22 is connected to a negative input of the first subtractor 3.
In one embodiment, as shown in fig. 6, the integration control circuit 4 may further include: an integrating controller 41, a bias current register 42, and a bias current digital-to-analog converter 43 connected in sequence; wherein:
an output end of the first subtracter 3 is connected with an input end of the integration controller 41;
the output end of the bias current register 42 is connected with the negative electrode input end of the second subtracter 6 and the input end of the bias current digital-to-analog converter 43 respectively;
an output terminal of the bias current digital-to-analog converter 43 is connected to an input terminal of the bias current driving circuit 5.
In one embodiment, as shown in fig. 6, the proportional control circuit 7 may further include: a proportional controller 71, a modulation current register 72, and a modulation current digital-to-analog converter 73; wherein:
the output end of the second subtracter 6 is connected with the input end of the proportional controller 71, and the proportional controller 71 also comprises the input end of the control coefficient E; an output end of the proportional controller 71 is connected with an input end of the modulation current register 72;
an output end of the modulation current register 72 is connected with an input end of the modulation current digital-to-analog converter 73;
an output terminal of the modulation current digital-to-analog converter 73 is connected to an input terminal of the modulation current driving circuit 5.
In the embodiment shown in fig. 6, the optical signal output from the laser emission circuit 1 is sequentially processed by the backlight signal detection circuit 21 and the low-pass filter 22 and then input to the first subtractor 3; the bias current register 42 outputs a bias current value to the second subtractor 6; the control coefficient E acts on the proportional controller 71; the positive electrode of the first subtractor 3 is further connected to a digital-to-analog converter 31 for converting the digital current signal into an analog current signal.
In this embodiment, the backlight signal detection circuit 21 detects the backlight current generated by the backlight diode, and then passes through the low-pass filter 22 to be combined with the digital-to-analog converted power current control parameter I B The comparison (i.e., signal subtraction) is performed, and the comparison result is subjected to integration processing by the integration controller 41 to obtain a bias current value I m And stored in the bias current register 42, the bias current value I m The bias current required by the laser operation is controlled and regulated after digital-to-analog conversion, and is applied to the laser through a current coupling circuit, wherein the average optical power is kept stable by regulating the bias current.
When the laser device ages or the temperature changes, the slope changes, the modulation amplitude changes, and the extinction ratio changes. Specifically, the bias current value stored in the bias current register is overlapped with the aging coefficient of the laser, the modulation current is adjusted by controlling the current control end of the modulation current driving circuit after proportional control is performed through the control coefficient E, and the laser is driven by a driving signal, the modulation current and the bias current are coupled in a certain proportion, and corresponding optical signals are emitted. The dual-ring control scheme is adopted, the proportion control outer ring is added on the basis of the average power control inner ring, the purpose of stabilizing the extinction ratio is achieved by setting the control coefficient E of the proportion control outer ring, and the control coefficient E is related to a plurality of parameters, so that the control precision is higher.
The embodiment of the invention also provides a chip which comprises the laser emission automatic control circuit provided by the embodiment of the invention.
The embodiment of the invention also provides an optical module which comprises the laser emission automatic control circuit provided by the embodiment of the invention.
The embodiment of the invention also provides optical communication equipment which comprises the laser emission automatic control circuit provided by the embodiment of the invention.
The optical communication device includes, but is not limited to: switches, communication transmission devices, etc.
Based on the same inventive concept, the embodiment of the invention also provides a laser emission automatic control method, and because the principle of the method for solving the problem is similar to that of the laser emission automatic control circuit of the previous embodiment, the implementation of the method can refer to the implementation of the previous circuit, and the repetition is omitted.
The following is a method for automatically controlling laser emission according to an embodiment of the present invention, as shown in fig. 7, including the following steps S701 to S703:
s701, generating bias current controlled by average power according to feedback of emitted laser and preset power current control parameters;
s702, outputting a modulation current subjected to proportional control according to a preset laser aging parameter and a bias current value;
and S703, coupling the bias current and the modulation current and then applying the coupled bias current and the modulation current to the emitted laser.
In one embodiment, generating the bias current controlled by the average power in step S701 according to the feedback of the emitted laser light and the preset power current control parameter, as shown in fig. 8, may include the following steps S7011 to S7013;
s7011, detecting backlight current and carrying out low-pass filtering on a feedback signal of the emitted laser, and then subtracting with a preset power current control parameter;
s7012, integrating the result obtained by the subtraction operation to obtain a bias current value;
s7013, outputting a corresponding bias current according to the bias current value.
In one embodiment, outputting the modulation current subjected to proportional control in step S702 according to the preset laser aging parameter and the bias current value of the inner loop control circuit may include the following steps S7021 to S7023;
s7021, subtracting a preset ageing coefficient of the laser from a bias current value;
s7022, multiplying a result obtained by subtraction operation by a preset control coefficient E to obtain a modulation current value;
s7023, outputting a corresponding modulation current according to the modulation current value;
wherein, the control coefficient E= (1-Z)/(ZK-A)), Z is an equivalent modulation proportion coefficient, K is A current coupling coefficient of the modulation current and the bias current, and A is A modulation baseline lifting coefficient.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (13)
1. An automatic laser emission control circuit, characterized in that the control circuit comprises: an inner loop control circuit and an outer loop control circuit;
the inner loop control circuit is used for generating bias current controlled by average power according to feedback of the emitted laser and preset power current control parameters; coupling the bias current with the modulation current output by the outer ring control circuit and then applying the coupled bias current and the modulation current to the emitted laser;
the outer loop control circuit is used for outputting modulation current with proportion control according to preset laser aging parameters and bias current values of the inner loop control circuit;
the inner loop control circuit includes: the laser emission circuit (1), the detection filter circuit (2), the first subtracter (3), the integration control circuit (4), the bias current driving circuit (5) and the current coupling circuit (9) are connected in sequence and form a closed loop; the outer loop control circuit includes: a second subtracter (6), a proportion control circuit (7) and a modulation current driving circuit (8) which are connected in sequence;
wherein: the output end of the laser emission circuit (1) is connected with the input end of the detection filter circuit (2); the output end of the detection filter circuit (2) is connected with the negative electrode input end of the first subtracter (3), and the positive electrode input end of the first subtracter (3) is used for inputting preset power current control parameters; the output end of the first subtracter (3) is connected with the input end of the integration control circuit (4); the output end of the integration control circuit (4) is respectively connected with the input end of the bias current driving circuit (5) and the negative electrode input end of the second subtracter (6); the output end of the bias current driving circuit (5) is connected with the input end of the current coupling circuit (9);
the positive electrode input end of the second subtracter (6) is used for inputting the ageing parameters of the laser; the output end of the second subtracter (6) is connected with the input end of the proportional control circuit (7); the output end of the proportional control circuit (7) is connected with the input end of the modulation current driving circuit (8), and the output end of the modulation current driving circuit (8) is connected with the input end of the current coupling circuit (9);
the modulation current I output by the modulation current driving circuit (8) m And a bias current I outputted from the bias current driving circuit (5) d The method meets the following conditions: i m =E*(I d -I ’ ) The method comprises the steps of carrying out a first treatment on the surface of the The I is ’ Is the ageing parameter of the laser;
the control coefficient E= (1-Z)/(ZK-A) of the proportion control circuit (7), wherein Z is an equivalent modulation proportion coefficient, K is A current coupling coefficient of modulation current and bias current in the current coupling circuit (9), and A is A modulation baseline lifting coefficient.
2. A circuit as claimed in claim 1, characterized in that the coupling means of the current coupling circuit (9) comprise: a direct current coupling mode and an alternating current coupling mode.
3. The circuit of claim 2, wherein, in the dc coupling mode:
I d +K*I m =I 1
I d +AI m = I 0
in the ac coupling mode:
I d +K/2*I m =I 1
I d +(A-K/2)I m = I 0；
in the above, I m A modulation current output by the modulation current driving circuit; i d A bias current output from the bias current driving circuit;
k is a current coupling coefficient of the modulation current and the bias current in the current coupling circuit;
a is a modulation baseline lifting coefficient;
I 1 is the current at the laser '1' level;
I 0 is the current at the laser "0" level.
4. A circuit as claimed in claim 2 or 3, characterized in that the detection filter circuit (2) comprises: a backlight signal detection circuit (21) and a low-pass filter (22);
the output end of the laser emission circuit (1) is connected with the input end of the backlight signal detection circuit (21);
the output end of the backlight signal detection circuit (21) is connected with the input end of the low-pass filter (22);
an output of the low-pass filter (22) is connected to a negative input of the first subtractor (3).
5. A circuit as claimed in claim 2 or 3, characterized in that the integration control circuit (4) comprises: an integrating controller (41), a bias current register (42) and a bias current digital-to-analog converter (43) which are connected in sequence; wherein:
the output end of the first subtracter (3) is connected with the input end of the integration controller (41);
the output end of the bias current register (42) is respectively connected with the cathode input end of the second subtracter (6) and the input end of the bias current digital-to-analog converter (43);
the output end of the bias current digital-to-analog converter (43) is connected with the input end of the bias current driving circuit (5).
6. A circuit as claimed in claim 2 or 3, characterized in that the proportional control circuit (7) comprises: a proportional controller (71), a modulation current register (72) and a modulation current digital-to-analog converter (73); wherein:
the output end of the second subtracter (6) is connected with the input end of the proportional controller (71), and the proportional controller (71) further comprises the input end of the control coefficient E; the output end of the proportional controller (71) is connected with the input end of the modulation current register (72);
the output end of the modulation current register (72) is connected with the input end of the modulation current digital-to-analog converter (73);
an output end of the modulation current digital-to-analog converter (73) is connected with an input end of the modulation current driving circuit (8).
7. A circuit as claimed in claim 2 or 3, characterized in that the positive input of the first subtractor (3) is further connected to a digital-to-analog converter (31).
8. A chip comprising the laser emission automatic control circuit according to any one of claims 1 to 7.
9. An optical module comprising the laser emission automatic control circuit according to any one of claims 1 to 7.
10. An optical communication apparatus comprising the laser emission automatic control circuit according to any one of claims 1 to 7.
11. A laser emission automatic control method of a laser emission automatic control circuit according to any one of claims 1 to 7, comprising:
generating bias current controlled by average power according to feedback of the emitted laser and preset power current control parameters;
outputting a proportional controlled modulation current according to a preset laser aging parameter and a bias current value;
the bias current and the modulation current are coupled and then applied to the emitted laser light.
12. The method of claim 11, wherein generating the bias current controlled with the average power based on feedback of the emitted laser light and a preset power current control parameter comprises:
detecting and low-pass filtering the feedback signal of the emitted laser, and then subtracting with a preset power current control parameter;
integrating the result obtained by the subtraction operation to obtain a bias current value;
and outputting corresponding bias current according to the bias current value.
13. The method of claim 11, wherein outputting a proportionally controlled modulation current based on a preset laser burn-in parameter and a bias current value of the inner loop control circuit comprises:
subtracting a preset aging coefficient of the laser from a bias current value;
multiplying the result obtained by subtraction operation by a preset control coefficient E to obtain a modulation current value;
outputting a corresponding modulation current according to the modulation current value;
the control coefficient E= (1-Z)/(ZK-A), wherein Z is an equivalent modulation proportion coefficient, K is A current coupling coefficient of modulation current and bias current, and A is A modulation baseline lifting coefficient.
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| CN109449740B (en) * | 2018-12-26 | 2020-08-18 | 中国电子科技集团公司第四十四研究所 | Adaptive adjusting device for extinction ratio of optical module and control method thereof |
| CN109830887B (en) * | 2019-01-08 | 2024-02-23 | 淮阴工学院 | Average power and extinction ratio control circuit of semiconductor laser |
| US11411653B2 (en) * | 2020-12-16 | 2022-08-09 | Macom Technology Solutions Holdings, Inc. | Optical transmitter input resistance measurement and encoder/driver modulation current configuration techniques |
| CN114281147B (en) * | 2021-12-13 | 2023-06-09 | 中国电子科技集团公司第四十四研究所 | Automatic stabilizing circuit and method for output optical power of optical module |
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