Optical power acquisition device and method

Abstract

The invention discloses an optical power acquisition device and method, and relates to the technical field of optical signal detection. The device comprises a photoelectric detector for converting an optical signal into a current signal, a trans-impedance amplifier for converting the current signal into a pulse voltage signal, a peak value detector for detecting a peak value of the pulse voltage signal, an RC filter network for filtering noise of the pulse voltage signal, and a low-frequency amplifier for amplifying a low-frequency pulse voltage signal, the ADC acquisition module is used for converting the amplified pulse voltage signal into a digital signal; the first feedback network is used for adjusting the gain of the trans-impedance amplifier; the second feedback network is used for adjusting the gain of the low-frequency amplifier; the microcontroller is used for controlling the first feedback network to adjust the gain of the trans-impedance amplifier according to the peak value of the pulse voltage signal and controlling the second feedback network to adjust the gain of the low-frequency amplifier according to the digital signal; according to the invention, the collection precision of the optical power can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical signal detection, in particular to an optical power acquisition device and method. BACKGROUND

[0002] In the acquisition process of pulse optical power, the feedback network of the high-speed transimpedance amplifier (TIA) and the low-frequency amplifier is usually a fixed parameter. When the intensity of the input optical signal changes, the fixed feedback network cannot perfectly match the signal amplitude, thereby generating distortion and affecting the precision of the subsequent analog-to-digital converter (ADC) acquisition module.

[0003] Therefore, based on the above problems, there is an urgent need to provide an optical power acquisition device and method that can improve the acquisition precision of optical power. SUMMARY

[0004] The purpose of the present application is to provide an optical power acquisition device and method that can improve the acquisition precision of optical power.

[0005] To achieve the above purpose, the present application provides the following solutions: In a first aspect, the present application provides an optical power acquisition device, comprising: a photodetector, a transimpedance amplifier, a peak detector, an RC filter network, a low-frequency amplifier, an ADC acquisition module, a microcontroller, a first feedback network, and a second feedback network. The photodetector is used to obtain an optical signal and convert the optical signal into a current signal. The input end of the transimpedance amplifier is connected to the output end of the photodetector, and is used to convert the current signal into a pulse voltage signal. The input end of the peak detector is connected to the output end of the transimpedance amplifier, and is used to detect the peak value of the pulse voltage signal. The input end of the RC filter network is connected to the output end of the transimpedance amplifier, and is used to filter out noise from the pulse voltage signal to obtain a low-frequency pulse voltage signal. The input end of the low-frequency amplifier is connected to the output end of the RC filter network, and is used to amplify the low-frequency pulse voltage signal to obtain an amplified pulse voltage signal. The input end of the ADC acquisition module is connected to the output end of the low-frequency amplifier, and is used to convert the amplified pulse voltage signal into a digital signal. The first feedback network is connected to the feedback end of the transimpedance amplifier, and is used to adjust the gain of the transimpedance amplifier. The second feedback network is connected to the feedback end of the low-frequency amplifier, and is used to adjust the gain of the low-frequency amplifier. The microcontroller is connected with the peak detector, the ADC acquisition module, the first feedback network and the second feedback network respectively, and is configured to control the first feedback network to adjust the gain of the trans-impedance amplifier according to the peak value of the pulse voltage signal, and control the second feedback network to adjust the gain of the low-frequency amplifier according to the digital signal.

[0006] Optionally, the process of the microcontroller includes: When the peak value of the pulse voltage signal is greater than a first preset range threshold, the gain of the trans-impedance amplifier is adjusted to be lower; When the peak value of the pulse voltage signal is less than the first preset range threshold, the gain of the trans-impedance amplifier is adjusted to be higher; When the voltage value corresponding to the digital signal is greater than a second preset range threshold, the gain of the low-frequency amplifier is adjusted to be lower; When the voltage value corresponding to the digital signal is less than the second preset range threshold, the gain of the low-frequency amplifier is adjusted to be higher.

[0007] Optionally, the photoelectric detector is a photodiode.

[0008] Optionally, the first preset range threshold is 0mv-120mv.

[0009] Optionally, the second preset range threshold is 120mv-3000mv.

[0010] Optionally, the low-frequency amplifier is a non-inverting amplifier, and the non-inverting amplifier includes a plurality of operational amplifiers.

[0011] Optionally, the peak detector is a peak holding circuit, and the peak holding circuit includes an operational amplifier, a diode and a capacitor connected in series.

[0012] Optionally, the first feedback network includes a plurality of parallel resistance branches, each resistance branch includes a resistance and a switch tube connected in series, and the switch tube is connected with the microcontroller.

[0013] Optionally, the second feedback network includes a plurality of parallel resistance branches, each resistance branch includes a resistance and a switch tube connected in series, and the switch tube is connected with the microcontroller.

[0014] In a second aspect, the present application provides a method for collecting optical power, comprising: acquiring an optical signal by using a photoelectric detector, and converting the optical signal into a current signal; converting the current signal into a pulse voltage signal by using a trans-impedance amplifier, and determining the peak value of the pulse voltage signal by using a peak detector; controlling the gain of the trans-impedance amplifier by using a microcontroller according to the peak value; Filter the pulse voltage signal by using the RC filter network to obtain a low-frequency pulse voltage signal; Amplify the low-frequency pulse voltage signal by using a low-frequency amplifier to obtain an amplified pulse voltage signal; Convert the amplified pulse voltage signal into a digital signal by using an ADC acquisition module; According to the digital signal, adjust the gain of the low-frequency amplifier by using a microcontroller to control a second feedback network, and realize optical power acquisition; Perform multiple optical power acquisition to obtain corresponding digital signals respectively, and determine the mean value of the digital signals; Determine the optical power according to the mean value of the digital signals, the current gain of the transimpedance amplifier, and the current gain of the low-frequency amplifier.

[0015] According to the specific embodiments provided in the present application, the present application has the following technical effects: The present application provides an optical power acquisition device and method, which realizes accurate acquisition and conversion of optical signals by setting a high-response photodetector (PD); the transimpedance amplifier converts the current signal into a pulse voltage signal, further filters the noise of the pulse voltage signal by using an RC filter network, improves the noise suppression capability, and improves the acquisition accuracy of the optical signal; the low-frequency amplifier is used to amplify the low-frequency pulse voltage signal, thereby enhancing the amplitude of the low-frequency pulse voltage signal; the ADC acquisition module is used to convert the amplified pulse voltage signal into a digital signal, thereby realizing the acquisition of the optical power; the microcontroller (Microcontroller Unit, MCU) is used to control the first feedback network to adjust the gain of the transimpedance amplifier, and simultaneously control the second feedback network to adjust the gain of the low-frequency amplifier, thereby restricting the pulse voltage signal and the digital signal in a specific range, improving the accuracy and fidelity of the digital signal, realizing the dynamic adjustment of the first feedback network and the second feedback network, expanding the dynamic range of the optical power acquisition device, and further improving the acquisition accuracy of the optical power. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 A module schematic diagram of an optical power acquisition device in an embodiment of the present application; Figure 2 A linear relationship diagram of optical power and amplified pulse voltage signal in an embodiment of the present application; Figure 3 Figure 1 is a flowchart of a method for collecting optical power according to an embodiment of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative work fall within the scope of protection of the present application.

[0019] In order to make the above objects, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0020] In one exemplary embodiment, as shown in Figure 1, an optical power collection device is provided, comprising a photodetector, a transimpedance amplifier, a peak detector, an RC filter network, a low-frequency amplifier, an ADC acquisition module, a microcontroller, a first feedback network and a second feedback network. Figure 1 The photodetector is used to acquire an optical signal and convert the optical signal into a current signal. Specifically, the photodetector is a photodiode, and the optical signal is a high-speed pulsed optical signal.

[0021] The input end of the transimpedance amplifier is connected to the output end of the photodetector, and is used to convert the current signal into a pulsed voltage signal.

[0022] The input end of the peak detector is connected to the output end of the transimpedance amplifier, and is used to detect the peak value of the pulsed voltage signal. Specifically, the peak detector is a peak holding circuit, and the peak holding circuit comprises an operational amplifier, a diode and a capacitor connected in series.

[0023] The input end of the RC filter network is connected to the output end of the transimpedance amplifier, and is used to filter out noise from the pulsed voltage signal to obtain a low-frequency pulsed voltage signal. Specifically, the RC filter network is used to filter out high-frequency noise in the pulsed voltage signal.

[0024] The input end of the low-frequency amplifier is connected to the output end of the RC filter network, and is used to amplify the low-frequency pulsed voltage signal to obtain an amplified pulsed voltage signal. The low-frequency amplifier of the present application is a non-inverting amplifier, and the non-inverting amplifier comprises a plurality of operational amplifiers.

[0025] The input end of the ADC acquisition module is connected to the output end of the low-frequency amplifier, and is used to convert the amplified pulsed voltage signal into a digital signal.

[0026]

[0027] ​The first feedback network is connected with a feedback end of the transimpedance amplifier, and is used for adjusting the gain of the transimpedance amplifier. In the present application, the first feedback network comprises a plurality of parallel resistance branches; each resistance branch comprises a resistance and a switch tube connected in series; and the switch tube is connected with the microcontroller.

[0028] The second feedback network is connected with a feedback end of the low-frequency amplifier, and is used for adjusting the gain of the low-frequency amplifier. In the present application, the second feedback network comprises a plurality of parallel resistance branches; each resistance branch comprises a resistance and a switch tube connected in series; and the switch tube is connected with the microcontroller.

[0029] The microcontroller is connected with the peak detector, the ADC acquisition module, the first feedback network and the second feedback network respectively, and is used for controlling the first feedback network to adjust the gain of the transimpedance amplifier according to the peak value of the pulse voltage signal; and controlling the second feedback network to adjust the gain of the low-frequency amplifier according to the digital signal.

[0030] Specifically, the microcontroller receives the peak value of the pulse voltage signal determined by the peak detector, and controls the first feedback network to reduce the gain of the transimpedance amplifier when the peak value of the pulse voltage signal is greater than a first preset range threshold; and controls the first feedback network to increase the gain of the transimpedance amplifier when the peak value of the pulse voltage signal is less than the first preset range threshold. In the present application, the first preset range threshold is 0mv-120mv.

[0031] The microcontroller receives the digital signal determined by the ADC acquisition module, and determines the corresponding voltage value according to the digital signal, and controls the second feedback network to reduce the gain of the low-frequency amplifier when the voltage value corresponding to the digital signal is greater than a second preset range threshold; and controls the second feedback network to increase the gain of the low-frequency amplifier when the voltage value corresponding to the digital signal is less than the second preset range threshold. In the present application, the second preset range threshold is 120mv-3000mv.

[0032] In addition, the microcontroller is also used for initializing the default state of the first feedback network and the second feedback network.

[0033] The optical power acquisition device is used to acquire the optical signal and obtain the corresponding digital signal, which is a first optical power acquisition, and the average power acquisition of the pulse light can be obtained through the cyclic acquisition process.

[0034] The relationship between the optical power y and the amplified pulse voltage signal x is a linear relationship, as shown in the following formula (1): Figure 2 wherein, R represents the complete fitting data.

[0035] In an exemplary embodiment, as shown in the following formula (2), an optical power acquisition method is provided, and the optical power acquisition method utilizes an optical power acquisition implementation, and specifically comprises the following S1 to S9. Wherein: Figure 3 ​S1: obtaining a light signal by using a photodetector, and converting the light signal into a current signal.

[0036] Before obtaining the light signal, first initializing the light power collection device by using the microcontroller, and setting the first feedback network and the second feedback network to the default state.

[0037] After obtaining the light signal by using the photodetector and converting the light signal into the current signal, sending the current signal to the transimpedance amplifier.

[0038] S2: converting the current signal into a pulse voltage signal by using the transimpedance amplifier; and determining the peak value of the pulse voltage signal by using the peak value detector.

[0039] After the transimpedance amplifier receives the current signal, the current signal is converted into a pulse voltage signal, and the pulse voltage signal is divided into two paths, one of which is input to the RC filter network, and the other of which is input to the peak value detector. The peak value detector detects the peak value (peak voltage) of the pulse voltage signal and sends the peak value to the microcontroller.

[0040] S3: adjusting the gain of the transimpedance amplifier by using the microcontroller according to the peak value.

[0041] After the microcontroller receives the peak value sent by the peak value detector, it determines whether the peak value is within the first preset range threshold. If the peak value is greater than the first preset range threshold, the microcontroller controls the first feedback network to switch to a smaller feedback resistance to reduce the gain of the transimpedance amplifier; if the peak value is less than the first preset range threshold, the microcontroller controls the first feedback network to switch to a larger feedback resistance to increase the gain of the transimpedance amplifier, so as to ensure that the pulse voltage signal output by the low transimpedance amplifier is always within the first preset range threshold.

[0042] S4: filtering the pulse voltage signal by using the RC filter network to obtain a low-frequency pulse voltage signal.

[0043] The RC filter network receives the pulse voltage signal sent by the transimpedance amplifier and filters out the high-frequency noise in the pulse voltage signal to obtain a low-frequency pulse voltage signal, and sends the low-frequency pulse voltage signal to the low-frequency amplifier.

[0044] S5: amplifying the low-frequency pulse voltage signal by using the low-frequency amplifier to obtain an amplified pulse voltage signal.

[0045] S6: converting the amplified pulse voltage signal into a digital signal by using the ADC acquisition module.

[0046] S7: adjusting the gain of the low-frequency amplifier by using the microcontroller according to the digital signal, and realizing light power collection.

[0047] The microcontroller receives the digital signal sent by the ADC acquisition module, determines the voltage value corresponding to the digital signal, and determines whether the voltage value is within a second preset range threshold (for example, 20%-80% of the full range of the ADC acquisition module). If the voltage value is greater than the second preset range threshold, the microcontroller controls the second feedback network to switch to a smaller feedback resistor to reduce the gain of the low-frequency amplifier. If the voltage value is less than the second preset range threshold, the microcontroller controls the second feedback network to switch to a larger feedback resistor to increase the gain of the low-frequency amplifier. This ensures that the amplified pulse voltage signal output by the low-frequency amplifier can be accurately acquired by the ADC acquisition module, avoiding saturation of the ADC acquisition module or excessive quantization error.

[0048] S8: Perform multiple optical power acquisitions to obtain corresponding digital signals, and determine the average of the digital signals.

[0049] The cyclic acquisition process ensures continuous and accurate measurement of the average optical signal power, making the application suitable for detecting optical signals of various intensities.

[0050] S9: Determine the optical power based on the average of the digital signals, the current gain of the transimpedance amplifier, and the current gain of the low-frequency amplifier.

[0051] Specifically, the optical power acquisition process is repeated in a loop. Whenever the intensity of the input optical signal changes, the microcontroller adjusts the first feedback network and the second feedback network to ensure that the optical power acquisition device is always in the best state. The microcontroller accumulates multiple digital signals acquired by the ADC acquisition module, calculates the average voltage, and then converts it to the average optical power based on the gain of the transimpedance amplifier and the gain of the low-frequency amplifier.

[0052] The application realizes a repletion frequency of 200kHz-1MHz and a pulse width of 100us-400us, which can be adjusted. Under the condition that the total input signal light is in the power range of-3 to-28dBm, the application can accurately acquire the optical signal without distortion. A high-response photodetector is used in combination with a high-speed transimpedance amplifier to convert weak optical signals into pulse voltage signals. By optimizing the bandwidth and noise suppression capability of the preamplifier circuit, the dynamic response capability of the optical power acquisition device to the pulse voltage signal is improved. In the control loop, the gain is adjusted in real time to improve the acquisition accuracy of the photodetector for high-speed pulse optical signals, thereby realizing fast and stable gain adjustment control and ensuring that the optical power acquisition device can accurately acquire the optical power when the input optical power changes.

[0053] When the duty cycle of the optical signal is small, the peak power is high but the average power is low, which results in that the photoelectric detector not only can bear the instantaneous high-intensity light impact to accurately capture the peak signal when acquiring the optical signal, but also needs to maintain sufficient sensitivity to the weak signal (the optical signal lower than the average power) to avoid saturation distortion in the high peak value and to avoid the problem that the effective signal cannot be identified due to noise in the low average power section. When the duty cycle of the optical signal is large, the peak power is low but the average power is high, at this time, the photoelectric detector can sensitively capture the characteristics of the optical signal with high average power, and then appropriately reduce the gain through the feedback mechanism to avoid the problems of circuit noise accumulation and signal oversaturation caused by long-time high-power input, so as to ensure that the output digital signal is always in the linear working interval and maintain the stability and accuracy of the measurement data.

[0054] The technical features of the above embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present disclosure.

[0055] The principles and implementation manners of the present application are described by using specific examples in the present disclosure, and the above embodiments are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the present application. In conclusion, the content of the present disclosure should not be understood as a limitation of the present application.

Claims

1. An optical power acquisition device, characterized in that, The optical power acquisition device includes: a photodetector, a transimpedance amplifier, a peak detector, an RC filter network, a low-frequency amplifier, an ADC acquisition module, a microcontroller, a first feedback network, and a second feedback network. The photodetector is used to acquire optical signals and convert the optical signals into current signals. The input terminal of the transimpedance amplifier is connected to the output terminal of the photodetector, and is used to convert the current signal into a pulse voltage signal. The input terminal of the peak detector is connected to the output terminal of the transimpedance amplifier, and is used to detect the peak value of the pulse voltage signal; The input terminal of the RC filter network is connected to the output terminal of the transimpedance amplifier to filter out noise from the pulse voltage signal and obtain a low-frequency pulse voltage signal. The input terminal of the low-frequency amplifier is connected to the output terminal of the RC filter network to amplify the low-frequency pulse voltage signal and obtain the amplified pulse voltage signal. The input terminal of the ADC acquisition module is connected to the output terminal of the low-frequency amplifier, and is used to convert the amplified pulse voltage signal into a digital signal. The first feedback network is connected to the feedback terminal of the transimpedance amplifier and is used to adjust the gain of the transimpedance amplifier; The second feedback network is connected to the feedback terminal of the low-frequency amplifier and is used to adjust the gain of the low-frequency amplifier; The microcontroller is connected to the peak detector, the ADC acquisition module, the first feedback network, and the second feedback network, respectively, and is used to control the first feedback network to adjust the gain of the transimpedance amplifier according to the peak value of the pulse voltage signal; and to control the second feedback network to adjust the gain of the low-frequency amplifier according to the digital signal.

2. The optical power acquisition device according to claim 1, characterized in that, The microcontroller's processing includes: When the peak value of the pulse voltage signal exceeds the first preset range threshold, the gain of the transimpedance amplifier is reduced. When the peak value of the pulse voltage signal is less than the first preset range threshold, the gain of the transimpedance amplifier is increased. When the voltage value corresponding to the digital signal is greater than the second preset range threshold, the gain of the low-frequency amplifier will be reduced. When the voltage value corresponding to the digital signal is less than the second preset range threshold, the gain of the low-frequency amplifier is increased.

3. The optical power acquisition device according to claim 1, characterized in that, The photodetector is a photodiode.

4. The optical power acquisition device according to claim 2, characterized in that, The first preset range threshold is 0mv-120mv.

5. The optical power acquisition device according to claim 2, characterized in that, The second preset range threshold is 120mv-3000mv.

6. The optical power acquisition device according to claim 1, characterized in that, The low-frequency amplifier is a non-inverting amplifier; the non-inverting amplifier includes multiple operational amplifiers.

7. The optical power acquisition device according to claim 1, characterized in that, The peak detector is a peak hold circuit; the peak hold circuit includes an operational amplifier, a diode, and a capacitor connected in series.

8. The optical power acquisition device according to claim 1, characterized in that, The first feedback network includes multiple parallel resistor branches; each resistor branch includes a resistor and a switching transistor connected in series; the switching transistor is connected to a microcontroller.

9. The optical power acquisition device according to claim 1, characterized in that, The second feedback network includes multiple parallel resistor branches; each resistor branch includes a resistor and a switching transistor connected in series; the switching transistor is connected to the microcontroller.

10. A method for acquiring optical power, applied to the optical power acquisition device according to any one of claims 1-9, characterized in that, The optical power acquisition method includes: Optical signals are acquired using photodetectors and then converted into electrical signals. A transimpedance amplifier is used to convert the current signal into a pulse voltage signal; and a peak detector is used to determine the peak value of the pulse voltage signal. Based on the peak value, the gain of the transimpedance amplifier is adjusted by using a microcontroller to control the first feedback network. The pulse voltage signal is filtered using an RC filter network to obtain a low-frequency pulse voltage signal; The low-frequency pulse voltage signal is amplified using a low-frequency amplifier to obtain the amplified pulse voltage signal; The amplified pulse voltage signal is converted into a digital signal using an ADC acquisition module. Based on the digital signal, the gain of the low-frequency amplifier is adjusted by using a microcontroller to control the second feedback network, thereby realizing optical power acquisition; Multiple optical power acquisitions were performed to obtain the corresponding digital signals, and the average value of the digital signals was determined. The optical power is determined based on the mean of the digital signal, the current gain of the transimpedance amplifier, and the current gain of the low-frequency amplifier.

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