CN212905520U - Optical signal transmitting and detecting system based on balance detector - Google Patents
Optical signal transmitting and detecting system based on balance detector Download PDFInfo
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- CN212905520U CN212905520U CN202021912564.XU CN202021912564U CN212905520U CN 212905520 U CN212905520 U CN 212905520U CN 202021912564 U CN202021912564 U CN 202021912564U CN 212905520 U CN212905520 U CN 212905520U
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Abstract
The utility model provides a light signal transmission and detecting system based on balanced detector, the light beam splitter divides into a plurality of bundles of parallel beam with the light signal of laser instrument output, regard one of them bundle of parallel beam as reference beam and through fiber output and detected by current differential circuit, the residual beam is as the detecting beam and by gating switch gating output detecting beam, this detecting beam is detected by current differential circuit, current differential circuit regards reference beam as calibration signal, carry out subtraction processing with its photocurrent after the conversion and the photocurrent after the detecting beam conversion, with the error that reduces light source fluctuation etc. and arouse; the current differential circuit is provided with two photodiodes with the same parameters for detecting reference light and detection light, and a reverse power supply and a forward power supply are respectively used as power supplies, so that the signs of two paths of light current signals are opposite, the differential amplification effect is achieved, the direct current part subtraction and alternating current signal addition in two paths of light currents are realized, and further, the error caused by light source fluctuation and the like is reduced.
Description
Technical Field
The utility model relates to a laser detection technical field especially relates to optical signal transmission and detecting system based on balanced detector.
Background
Laser detection is widely used in industries such as industry, medical treatment, sensing and the like, and comprises a light emitting and receiving system. The basic components of the light emitting and receiving system should include: the device comprises a light emitting module, a light receiving module and a signal processing module. The optical transmitting module provides stable laser output, optical signals are transmitted in the optical fiber and modulated, and the optical receiving module detects the modulated optical signals and performs data processing through the signal processing module. Wherein small fluctuations of the laser light source cause large deviations in the measured quantity, resulting in large measurement errors. Therefore, the light receiving module is susceptible to errors caused by fluctuations of the light source in the light emitting module when detecting the light signal. Therefore, for solving the above problem, the utility model provides an optical signal transmission and detecting system based on balanced detector carries out the difference through adopting the reference light as calibration signal with other detecting light, reduces the error that light source fluctuation etc. arouses.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides an optical signal emission and detection system based on balanced detector carries out the difference through adopting reference light as calibration signal with other detected light, reduces the error that light source fluctuation etc. arouses.
The technical scheme of the utility model is realized like this: the utility model provides an optical signal transmitting and detecting system based on a balance detector, which comprises a laser, an optical beam splitter, a plurality of optical fibers, a detector and a processor, wherein the detector comprises a gating switch, a current differential circuit and an amplifying circuit;
the laser outputs optical signals and is connected with the optical beam splitter through optical fibers, the optical beam splitter divides the optical signals output by the laser into a plurality of parallel beams, one of the parallel beams is used as reference light and is output through the optical fibers and is detected by the current differential circuit, the rest parallel beams are used as detection light and are correspondingly connected with a plurality of input ends of the gating switch one by one through a plurality of optical fibers, the gating switch gates and outputs the detection light, the detection light is detected by the current differential circuit, the reference light and the detection light are converted into photocurrent and are subjected to differential processing by the current differential circuit, the processed photocurrent signals are output to the input end of the amplifying circuit by the current differential circuit, and the output end of the amplifying circuit is electrically connected with the analog input end of the processor.
Based on the above technical solution, preferably, the optical beam splitter equally divides the optical signal output by the laser into four parallel beams according to the intensity of the optical signal, wherein one of the parallel beams is used as the reference light, and the remaining three parallel beams are used as the probe light.
On the basis of the above technical solution, preferably, the current differential circuit includes a photodiode D10, a photodiode D11, a resistor R43, a resistor R44, a forward power supply and a reverse power supply;
the photodiode D10 detects the reference light and converts the reference light into photocurrent, the cathode of the photodiode D10 is electrically connected with the reverse power supply through the resistor R43, and the anode of the photodiode D10 is electrically connected with the input end of the amplifying circuit;
the photodiode D11 detects the probe light and converts it into photocurrent, the anode of the photodiode D11 is electrically connected to the forward power supply through the resistor R44, and the cathode of the photodiode D11 is electrically connected to the input terminal of the amplifying circuit.
On the basis of the technical scheme, preferably, the amplifying circuit comprises a trans-impedance amplifier, a high-pass filter and an in-phase amplifier;
the input end of the transimpedance amplifier is electrically connected with the output end of the current differential circuit, the output end of the transimpedance amplifier is electrically connected with the input end of the high-pass filter, and the output end of the high-pass filter is electrically connected with the analog input end of the processor through the in-phase amplifier.
Further preferably, the high-pass filter includes: a resistor R47, a resistor R48 and a capacitor C37;
the output end of the transimpedance amplifier is electrically connected with the input end of the non-inverting amplifier through a capacitor C37 and a resistor R47 which are sequentially connected, one end of a resistor R48 is electrically connected with the input end of the non-inverting amplifier, and the other end of the resistor R48 is grounded.
Further preferably, the non-inverting amplifier includes: operational amplifier TL0821, resistance R49 and resistance R50;
the output end of the transimpedance amplifier is electrically connected with a pin 5 of the operational amplifier TL0821 through a capacitor C37 and a resistor R47 which are sequentially connected, one end of a resistor R48 is electrically connected with the pin 5 of the operational amplifier TL0821, the resistor R49 is connected between the pin 6 and the pin 7 of the operational amplifier TL0821 in parallel, one end of the resistor R50 is electrically connected with the pin 6 of the operational amplifier TL0821, the other end of the resistor R50 is grounded, and the pin 7 of the operational amplifier TL0821 is electrically connected with the analog input end of the processor.
On the basis of the above technical solution, preferably, the optical power detection device further includes a first optical power detection circuit and a second optical power detection circuit;
the first optical power detection circuit detects the voltage at two ends of the resistor R43, amplifies the voltage and outputs the amplified voltage to the analog input end of the processor;
the second optical power detection circuit detects the voltage across the resistor R44, amplifies the voltage and outputs the amplified voltage to the analog input terminal of the processor.
The utility model discloses a light signal emission and detecting system based on balanced detector has following beneficial effect for prior art:
(1) the optical beam splitter divides an optical signal output by the laser into a plurality of parallel beams, one of the parallel beams is used as reference light and is output through an optical fiber and is detected by a current differential circuit, the rest beams are used as detection light and are gated by a gating switch to output the detection light, the detection light is detected by the current differential circuit, the reference light is used as a calibration signal by the current differential circuit, and the converted photocurrent is subtracted from the converted photocurrent of the detection light so as to reduce errors caused by light source fluctuation and the like;
(2) the current differential circuit is provided with two photodiodes with the same parameters for detecting reference light and detection light, and a reverse power supply and a forward power supply are respectively used as power supplies, so that the signs of two paths of light current signals are opposite, the differential amplification effect is achieved, the direct current part subtraction and alternating current signal addition in two paths of light currents are realized, and further, the error caused by light source fluctuation and the like is reduced;
(3) by arranging the first optical power detection circuit and the second optical power detection circuit, when the output voltages of the first optical power detection circuit and the second optical power detection circuit are different, the problem of signal-to-noise ratio reduction caused by nonuniform light splitting caused by a light splitting system is solved by adjusting the coupling efficiency of the optical beam splitter.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a structural diagram of the optical signal transmitting and detecting system based on the balance detector of the present invention;
fig. 2 is a circuit diagram of the detector in the optical signal transmitting and detecting system based on the balanced detector of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.
As shown in fig. 1, the optical signal transmitting and detecting system based on the balanced detector of the present invention includes a laser, an optical beam splitter, a plurality of optical fibers, a detector and a processor.
And the laser outputs an optical signal with stable power. Preferably, the laser is a semiconductor laser.
The optical beam splitter divides an optical signal output by the laser into a plurality of parallel beams, one of the parallel beams is used as reference light and is output through optical fibers and is detected by the current differential circuit, the rest beams are used as detection light and are transmitted through a plurality of optical fibers, the plurality of optical fibers simultaneously detect different physical quantities, and under the influence of the characteristics of the physical quantities to be detected, the detection light is output after being subjected to intensity modulation and is detected by the detector. The number of the beam splitting of the optical beam splitter is not suitable to be excessive in consideration of the problems of loss of optical signals in the optical fiber, detection range, measurement accuracy and the like. Preferably, in this embodiment, the optical beam splitter equally divides the optical signal output by the laser into four parallel beams according to the intensity of the optical signal, wherein one of the parallel beams is used as the reference light, the remaining three parallel beams are used as the probe light, the detection range of each path is 0 to 40dB, and the measurement accuracy is higher than 1%.
And the detector is used for detecting the reference light and the detection light, and carrying out difference, amplification and filtering processing on the electric signal obtained by converting the reference light and the electric signal obtained by converting one path of detection light. In this embodiment, the detector includes a gate switch, a current differential circuit, and an amplification circuit.
And the gating switch gates and outputs one path of the multiple beams of detection light. In this embodiment, the plurality of probe lights are connected to the plurality of input ends of the gating switch in a one-to-one correspondence manner through the plurality of optical fibers, the gating switch gates the probe lights to output, and the probe lights are detected by the current differential circuit. In this embodiment, the gating switch may be implemented by using the prior art, and will not be described in detail herein.
And the current difference circuit is used for respectively detecting the reference light and the detection light, using the reference light as a calibration signal and carrying out difference with one beam of detection light so as to reduce errors caused by light source fluctuation and the like. In the present embodiment, as shown in fig. 2, the current differential circuit includes a photodiode D10, a photodiode D11, a resistor R43, a resistor R44, a forward power supply, and a reverse power supply; specifically, the photodiode D10 detects the reference light and converts the reference light into a photocurrent, the cathode of the photodiode D10 is electrically connected to the reverse power supply through the resistor R43, and the anode of the photodiode D10 is electrically connected to the input terminal of the amplifying circuit; the photodiode D11 detects the probe light and converts it into photocurrent, the anode of the photodiode D11 is electrically connected to the forward power supply through the resistor R44, and the cathode of the photodiode D11 is electrically connected to the input terminal of the amplifying circuit. The photodiode D10 and the photodiode D11 adopt photodiodes with the same responsivity and response time characteristics and the same photodiode parameters, so that the random noise of the photodetectors can be the same as much as possible, and the noise of the system can be reduced through differential processing; the photodiode D10 detects reference light and converts the reference light into photocurrent, the photodiode D11 detects detection light and converts the detection light into photocurrent, and the photodiode D10 and the photodiode D11 respectively use a reverse power supply and a forward power supply as power supplies, so that signs of two paths of optical current signals are opposite, a differential amplification effect is achieved, direct current part subtraction and alternating current signal addition in the two paths of photocurrent are achieved, and errors caused by light source fluctuation and the like are reduced. In this embodiment, the forward power supply is labeled V +, and the reverse power supply is labeled V-.
Preferably, the optical splitter has the problem of nonuniform splitting, so that the signal-to-noise ratio of the system is easily reduced. In order to solve the above problem, in this embodiment, a first optical power detection circuit and a second optical power detection circuit are provided, where the first optical power detection circuit detects the voltage across the resistor R43, performs amplification processing, and outputs the amplified voltage to the analog input terminal of the processor; the second optical power detection circuit detects the voltage across the resistor R44, amplifies the voltage and outputs the amplified voltage to the analog input terminal of the processor. When the output voltages of the first optical power detection circuit and the second optical power detection circuit are different, the problem of signal-to-noise ratio reduction caused by nonuniform light splitting caused by a light splitting system is solved by adjusting the coupling efficiency of the optical beam splitter. In this embodiment, the first optical power detection circuit and the second optical power detection circuit can be implemented by using the prior art, and will not be described in detail herein.
And the amplifying circuit is used for amplifying and filtering the photocurrent signal output by the current differential circuit. Preferably, the amplifying circuit includes: a transimpedance amplifier, a high-pass filter, and a non-inverting amplifier.
And the trans-impedance amplifier converts the photocurrent signal into a voltage signal, realizes primary amplification of weak differential photocurrent, and outputs the amplified signal to the high-pass filter. The transimpedance amplifier can be implemented by the prior art, and preferably, in this embodiment, the transimpedance amplifier is as shown in fig. 2. Because the input resistance of the trans-impedance amplifier is smaller, the feedback resistance value can be larger under the same bandwidth, thereby reducing the noise current and being beneficial to improving the detection sensitivity.
And the high-pass filter only allows the middle-low frequency signals in the output signals of the trans-impedance amplifier to pass through, filters out high-frequency signals, reduces the frequency band of the signals and reduces noise. Preferably, in this embodiment, as shown in fig. 2, the high-pass filter includes: a resistor R47, a resistor R48 and a capacitor C37; specifically, the output end of the transimpedance amplifier is electrically connected to the input end of the non-inverting amplifier through a capacitor C37 and a resistor R47 which are connected in sequence, one end of the resistor R48 is electrically connected to the input end of the non-inverting amplifier, and the other end of the resistor R48 is grounded.
And the in-phase amplifier is used for amplifying the voltage signal output by the high-pass filter. In this embodiment, as shown in fig. 2, the non-inverting amplifier includes: operational amplifier TL0821, resistance R49 and resistance R50; specifically, the output end of the transimpedance amplifier is electrically connected to a pin 5 of the operational amplifier TL0821 through a capacitor C37 and a resistor R47 which are connected in sequence, one end of the resistor R48 is electrically connected to the pin 5 of the operational amplifier TL0821, the resistor R49 is connected in parallel between the pin 6 and the pin 7 of the operational amplifier TL0821, one end of the resistor R50 is electrically connected to the pin 6 of the operational amplifier TL0821, the other end of the resistor R50 is grounded, and the pin 7 of the operational amplifier TL0821 is electrically connected to the analog input end of the processor. Wherein, the voltage signal amplified by the in-phase amplifier is amplified by 11 times; the output of the non-inverting amplifier is labeled out and is output to the analog input of the processor.
The working principle of the embodiment is as follows: the laser outputs optical signals and transmits the optical signals to the optical beam splitter through optical fibers, the optical beam splitter divides the optical signals output by the laser into a plurality of parallel beams, one of the parallel beams is used as reference light and output through the optical fibers and is detected by the current differential circuit, the rest beams are used as detection light and transmitted through a plurality of optical fibers, the plurality of optical fibers simultaneously detect different physical quantities, under the influence of the characteristics of the physical quantity to be detected, the detection light is output after being subjected to intensity modulation, the detection light is gated and output by the gating switch and is detected by the current differential circuit, the reference light and the detection light are converted into light currents by the current differential circuit and are subjected to differential processing, the processed light current signals are output to the transimpedance amplifier by the current differential circuit, the photocurrent signals are converted into voltage signals by the transimpedance amplifier, and the voltage signals are output to the analog input end of the processor after being filtered by the high-pass filter and amplified by the in, the processor performs analog-to-digital conversion on the data.
The beneficial effect of this embodiment does: the optical beam splitter divides an optical signal output by the laser into a plurality of parallel beams, one of the parallel beams is used as reference light and is output through an optical fiber and is detected by a current differential circuit, the rest beams are used as detection light and are gated by a gating switch to output the detection light, the detection light is detected by the current differential circuit, the reference light is used as a calibration signal by the current differential circuit, and the converted photocurrent is subtracted from the converted photocurrent of the detection light so as to reduce errors caused by light source fluctuation and the like;
the current differential circuit is provided with two photodiodes with the same parameters for detecting reference light and detection light, and a reverse power supply and a forward power supply are respectively used as power supplies, so that the signs of two paths of light current signals are opposite, the differential amplification effect is achieved, the direct current part subtraction and alternating current signal addition in two paths of light currents are realized, and further, the error caused by light source fluctuation and the like is reduced;
by arranging the first optical power detection circuit and the second optical power detection circuit, when the output voltages of the first optical power detection circuit and the second optical power detection circuit are different, the problem of signal-to-noise ratio reduction caused by nonuniform light splitting caused by a light splitting system is solved by adjusting the coupling efficiency of the optical beam splitter.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. Optical signal transmission and detecting system based on balanced detector, it includes laser instrument, optical beam splitter, a plurality of optic fibre, detector and treater, its characterized in that: the detector comprises a gating switch, a current differential circuit and an amplifying circuit;
the laser outputs an optical signal and is connected with the optical beam splitter through an optical fiber, the optical beam splitter divides the optical signal output by the laser into a plurality of parallel beams, one of the parallel beams is used as reference light and is output through the optical fiber and is detected by the current differential circuit, the rest parallel beams are used as detection light and are correspondingly connected with a plurality of input ends of the gating switch one by one through a plurality of optical fibers, the gating switch gates and outputs the detection light, the detection light is detected by the current differential circuit, the reference light and the detection light are converted into photocurrent and are subjected to differential processing by the current differential circuit, the processed photocurrent signal is output to the input end of the amplifying circuit by the current differential circuit, and the output end of the amplifying circuit is electrically connected with the analog input end of the processor.
2. The balanced detector-based optical signal transmission and detection system of claim 1, wherein: the optical beam splitter equally divides an optical signal output by the laser into four parallel beams according to the intensity of the optical signal, wherein one parallel beam is used as reference light, and the remaining three parallel beams are used as probe light.
3. The balanced detector-based optical signal transmission and detection system of claim 1, wherein: the current differential circuit comprises a photodiode D10, a photodiode D11, a resistor R43, a resistor R44, a forward power supply and a reverse power supply;
the photodiode D10 detects the reference light and converts the reference light into photocurrent, the cathode of the photodiode D10 is electrically connected with a reverse power supply through a resistor R43, and the anode of the photodiode D10 is electrically connected with the input end of the amplifying circuit;
the photodiode D11 detects the probe light and converts the probe light into photocurrent, the anode of the photodiode D11 is electrically connected with the forward power supply through the resistor R44, and the cathode of the photodiode D11 is electrically connected with the input end of the amplifying circuit.
4. The balanced detector-based optical signal transmission and detection system of claim 1, wherein: the amplifying circuit comprises a trans-impedance amplifier, a high-pass filter and an in-phase amplifier;
the input end of the transimpedance amplifier is electrically connected with the output end of the current differential circuit, the output end of the transimpedance amplifier is electrically connected with the input end of the high-pass filter, and the output end of the high-pass filter is electrically connected with the analog input end of the processor through the in-phase amplifier.
5. The balanced detector-based optical signal transmission and detection system of claim 4, wherein: the high pass filter includes: a resistor R47, a resistor R48 and a capacitor C37;
the output end of the transimpedance amplifier is electrically connected with the input end of the non-inverting amplifier through a capacitor C37 and a resistor R47 which are sequentially connected, one end of a resistor R48 is electrically connected with the input end of the non-inverting amplifier, and the other end of the resistor R48 is grounded.
6. The balanced detector-based optical signal transmission and detection system of claim 5, wherein: the non-inverting amplifier includes: operational amplifier TL0821, resistance R49 and resistance R50;
the output end of the transimpedance amplifier is electrically connected with a pin 5 of an operational amplifier TL0821 through a capacitor C37 and a resistor R47 which are sequentially connected, one end of a resistor R48 is electrically connected with the pin 5 of the operational amplifier TL0821, the resistor R49 is connected between the pin 6 and the pin 7 of the operational amplifier TL0821 in parallel, one end of a resistor R50 is electrically connected with the pin 6 of the operational amplifier TL0821, the other end of the resistor R50 is grounded, and the pin 7 of the operational amplifier TL0821 is electrically connected with the analog input end of the processor.
7. The balanced detector-based optical signal transmission and detection system of claim 3, wherein: the optical power detection circuit also comprises a first optical power detection circuit and a second optical power detection circuit;
the first optical power detection circuit detects the voltage at two ends of the resistor R43, amplifies the voltage and outputs the amplified voltage to the analog input end of the processor;
the second optical power detection circuit detects the voltage at two ends of the resistor R44, amplifies the voltage and outputs the amplified voltage to the analog input end of the processor.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113654460A (en) * | 2021-08-04 | 2021-11-16 | 之江实验室 | Differential four-quadrant photoelectric detector suitable for position detection of optical tweezers system |
| CN114324125A (en) * | 2021-12-30 | 2022-04-12 | 苏州苏信环境科技有限公司 | Particle counting sensor, method and device for controlling same, and medium |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113654460A (en) * | 2021-08-04 | 2021-11-16 | 之江实验室 | Differential four-quadrant photoelectric detector suitable for position detection of optical tweezers system |
| CN113654460B (en) * | 2021-08-04 | 2023-09-19 | 之江实验室 | Differential four-quadrant photoelectric detector suitable for position detection of optical tweezers system |
| CN114324125A (en) * | 2021-12-30 | 2022-04-12 | 苏州苏信环境科技有限公司 | Particle counting sensor, method and device for controlling same, and medium |
| CN114324125B (en) * | 2021-12-30 | 2024-03-26 | 苏州苏信环境科技有限公司 | Particle counting sensor, method, device and medium for controlling particle counting sensor |
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