CN116170085A - Photoelectric fusion superheterodyne terahertz channel monitoring system - Google Patents

Photoelectric fusion superheterodyne terahertz channel monitoring system Download PDF

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Publication number
CN116170085A
CN116170085A CN202310175835.XA CN202310175835A CN116170085A CN 116170085 A CN116170085 A CN 116170085A CN 202310175835 A CN202310175835 A CN 202310175835A CN 116170085 A CN116170085 A CN 116170085A
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optical
terahertz
signal
frequency
unit
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张健
陈飞良
李沫
杨帆
姜昊
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University of Electronic Science and Technology of China
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University of Electronic Science and Technology of China
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/90—Non-optical transmission systems, e.g. transmission systems employing non-photonic corpuscular radiation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/079—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using measurements of the data signal
    • H04B10/0795—Performance monitoring; Measurement of transmission parameters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/10—Nuclear fusion reactors

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optics & Photonics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

The invention provides a photoelectric fusion superheterodyne terahertz channel monitoring system, and belongs to the technical field of millimeter wave/terahertz information. The system comprises a terahertz receiving unit, an optical carrier radio frequency unit, a tuning optical local oscillator unit, an optoelectronic down-conversion unit and a filtering and processing unit. The system adopts a sweep frequency laser as a tuning type optical local oscillation unit to output a tuning type optical local oscillation signal, and performs photoelectric mixing down-conversion to a baseband for processing with a terahertz signal or an intermediate frequency signal loaded into an optical frequency domain. The invention fully utilizes the large bandwidth characteristic of the photoelectric frequency conversion device, overcomes the electronic bottleneck of signal processing on the traditional electric frequency domain, and directly realizes ultra-wideband terahertz signal monitoring on a single-channel monitoring machine; the band-pass optical filter is also utilized to conveniently monitor the optical carrier radio frequency signal in a segmented way, so that the multi-channel photoelectric fusion superheterodyne terahertz channel monitoring is realized, the testing rate is greatly improved, and the frequency testing coverage range can be effectively expanded.

Description

Photoelectric fusion superheterodyne terahertz channel monitoring system
Technical Field
The invention belongs to the technical field of millimeter wave/terahertz information, and particularly relates to a photoelectric fusion superheterodyne terahertz channel monitoring system.
Background
The terahertz channel monitor is a key device for monitoring and identifying channel environment signals in frequency-adaptive terahertz communication, radar and other systems, and is of great importance to electromagnetic environment monitoring, adaptive frequency allocation, anti-interference, anti-interception and the like of terahertz frequency bands. The high frequency band and ultra wideband are one of the main characteristics of the terahertz system, and in recent years, as the working frequency band is continuously developed to the higher frequency band, the working bandwidth of the system is continuously increased. The receiving bandwidth, the receiving sensitivity, the spectrum resolution and the like of the channel monitor are required to be higher. The channel monitor based on superheterodyne receiving utilizes a tunable local oscillator to heterodyne down-convert a signal to be detected to an intermediate frequency or baseband frequency band, and then performs digital-to-analog conversion processing to obtain information such as frequency, bandwidth, phase, signal modulation system and the like of the signal to be detected. The superheterodyne channel monitor has a large receiving dynamic range and high receiving sensitivity, has advantages in high-frequency and weak signal reception, and the output signal has high selectivity and good frequency characteristics, and is easy to adjust. In order to suppress the strong interference and make it have good selectivity, a pre-selection radio frequency filter and an intermediate frequency filter are generally installed in the superheterodyne channel monitor. However, the conventional pure electronic superheterodyne channel monitor based on an electric filter is limited by bandwidth and power roll-off of the tunable local oscillation source and the electric filter in a high frequency band, and multiple-stage frequency conversion is often required when the high-frequency broadband signal is received, a large number of filters, mixers and local oscillation signals are required, so that the problems of large volume power consumption, poor electromagnetic compatibility and the like exist, and the monitoring requirement of the terahertz frequency band superheterodyne bandwidth spectrum is difficult to well meet.
The photoelectric fusion channel monitoring technology is that radio frequency signals are modulated onto light, and then the radio frequency signals are subjected to filtering, channelizing, mixing and other processing in an optical domain and then are converted into electric signals with proper bandwidth through photoelectric conversion so as to match the processing capacity of electronic devices in a later digital processing module. The method uses photonics to process radio frequency signals in the optical domain, can fully utilize the large bandwidth characteristics of photoelectric frequency conversion devices such as an electro-optical modulator, a photoelectric mixer and the like, overcomes the electronic bottleneck of signal processing in the traditional electric domain, improves the sampling and control speed of signals, optimizes and improves the performance of a channel monitor in the aspects of processing bandwidth, dynamic range, frequency response flatness, electromagnetic interference resistance and the like, reduces the volume and weight of a system, and reduces the cost of the system. The current photoelectric fusion channel monitoring technology has been widely studied and applied in the field of microwave photons, and can not only measure the instantaneous frequency of a microwave signal, but also monitor a plurality of parameters such as bandwidth, signal modulation system, frequency shift, direction and the like. However, at the terahertz frequency band with higher frequency and larger working bandwidth, a photoelectric fusion terahertz channel monitor scheme is not yet available.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a photoelectric fusion superheterodyne terahertz channel monitoring system, and aims to provide a technical scheme capable of being used for monitoring a high-frequency-band and ultra-wideband terahertz channel.
The technical aim of the invention is realized by the following technical scheme:
a photoelectric fusion superheterodyne terahertz channel monitoring system comprises a terahertz receiving unit, an optical carrier radio frequency unit, a tuning type optical local oscillator unit, a photoelectric down-conversion unit and a filtering and processing unit.
The terahertz receiving unit is used for receiving terahertz signals to be detected and directly loading or processing the terahertz signals to be detected and then loading the terahertz signals to the optical carrier radio frequency unit; the processing mode is amplification and/or down-conversion to an intermediate frequency, and the terahertz signal to be detected is subjected to down-conversion to the intermediate frequency to obtain an intermediate frequency signal.
The optical carrier radio frequency unit is used for loading the received terahertz signals or intermediate frequency signals onto an optical frequency domain, obtaining optical carrier radio frequency signals and transmitting the optical carrier radio frequency signals to the photoelectric down-conversion unit.
The tuning type optical local oscillation unit comprises a sweep frequency laser and is used for generating an optical local oscillation signal with tunable wavelength and transmitting the optical local oscillation signal to the photoelectric down-conversion unit.
The photoelectric down-conversion unit is used for carrying out optical frequency mixing on the optical carrier radio frequency signal and the optical local oscillation signal and down-converting the optical carrier radio frequency signal and the optical local oscillation signal to a baseband, obtaining a difference frequency signal and transmitting the difference frequency signal to the filtering and processing unit.
The filtering and processing unit is used for filtering the difference frequency signal to obtain a baseband signal, and then obtaining information of the terahertz signal to be detected through sampling and digital processing.
Further, the optical carrier radio frequency unit comprises a frequency stabilization laser, an electro-optic modulator and at least one optical filter; the frequency stabilization laser is used for generating carrier frequency signals and loading the carrier frequency signals to the electro-optical modulator; the electro-optical modulator is used for receiving the carrier frequency signal and the terahertz signal or the intermediate frequency signal, and modulating to generate an optical carrier radio frequency signal; the optical filter is used for carrying out passband filtering on the optical carrier radio frequency signal. The multi-channel photoelectric fusion superheterodyne terahertz channel monitoring machine can be used for monitoring the optical carrier radio frequency signals in a segmented mode by utilizing the plurality of band-pass optical filters, the corresponding tuning type optical local oscillation units and the corresponding photoelectric down-conversion units, so that the frequency testing coverage range is expanded, and the testing rate is improved.
Further, when the optical carrier radio frequency signals output by the optical carrier radio frequency unit are n paths, the number of the tuning optical local oscillator units and the photoelectric down-conversion units is also n.
Further, the photoelectric down-conversion unit is a photoelectric mixer.
Further, the filtering and processing unit comprises an electric filter and an analog-to-digital converter (ADC); the electric filter is a low-pass filter and is used for filtering the difference frequency signal to obtain a baseband signal, and inputting the baseband signal into the analog-to-digital converter for sampling and digitizing to obtain information of the terahertz signal to be detected.
Further, the optical filter is a bandpass filter.
The invention has the following advantages:
1. the photoelectric fusion superheterodyne terahertz channel monitoring system provided by the invention adopts the sweep frequency laser to output the tuning type optical local oscillation signal, does not need a tuning type radio frequency local oscillation source, does not need frequency multiplication, and can be directly suitable for sweep frequency monitoring of terahertz frequency bands.
2. The photoelectric fusion superheterodyne terahertz channel monitoring system provided by the invention fully utilizes the large bandwidth characteristics of photoelectric frequency conversion devices such as an electro-optic modulator, a photoelectric mixer and the like, overcomes the electronic bottleneck of signal processing in the traditional electric domain, and can directly realize the monitoring of the ultra-wideband terahertz signal on a single-channel monitoring machine.
3. The photoelectric fusion superheterodyne terahertz channel monitoring system provided by the invention can also conveniently monitor the optical carrier radio frequency signals in a segmented way by utilizing the band-pass optical filter array, so that the multichannel photoelectric fusion superheterodyne terahertz channel monitoring machine is realized, the testing rate can be greatly improved, and the frequency testing coverage range can be effectively expanded.
Drawings
Fig. 1 is a schematic structural diagram of a photoelectric fusion superheterodyne terahertz channel monitor based on intermediate frequency according to embodiment 1.
Fig. 2 is a schematic structural diagram of a photoelectric fusion superheterodyne terahertz channel monitor for terahertz direct up-conversion in the optical frequency domain according to embodiment 2.
Fig. 3 is a schematic structural diagram of a multi-channel photoelectric fusion superheterodyne terahertz channel monitor according to embodiment 3.
Detailed Description
The technical scheme of the invention is further described below with reference to the accompanying drawings and examples.
Example 1
A photoelectric fusion superheterodyne terahertz channel monitor structure diagram based on intermediate frequency is shown in fig. 1. The basic constitution and working process are as follows:
the terahertz receiving unit is formed by an antenna, a power amplifier, a terahertz local vibration source and a terahertz electric mixer, and is used for measuring a terahertz signal f to be measured THz After receiving and amplifying, the local oscillation signal f generated by the terahertz local oscillation source LO Intermediate frequency signal f obtained by down-conversion together with terahertz electric mixer THz -f LO The method comprises the steps of carrying out a first treatment on the surface of the The intermediate frequency signal f THz -f LO Loaded onto the electro-optical modulator of the optical radio frequency unit through the radio frequency cable.
The optical carrier radio frequency unit comprises a frequency stabilizing laserAn optical device, an electro-optical modulator, and an optical filter; wherein carrier frequency signal f output by frequency stabilized laser 0 And intermediate frequency signal f THz -f LO Modulated by an electro-optical modulator to generate an optical carrier radio frequency signal f 0 +f THz -f LO And filtering out the optical carrier radio frequency signal through a band-pass optical filter and transmitting the optical carrier radio frequency signal to the photoelectric mixer.
Optical carrier radio frequency signal f 0 +f THz -f LO Tuning optical local oscillation signal f output by sweep frequency laser L The optical fibers are combined and then input into a photoelectric mixer for mixing to obtain a difference frequency signal f of the optical fibers and the photoelectric mixer L -f 0 -f THz +f LO And is input to the low-pass filter of the filtering and processing unit.
When the frequency of the difference frequency signal is within the range of the low-pass filter, a baseband signal f is output B Analog-to-digital conversion is carried out in the ADC so as to obtain the frequency f of the terahertz signal to be detected THz ＝f L -f 0 +f LO -f B Phase, bandwidth, signal modulation regime, frequency shift, direction.
The method has the advantages that the bandwidth of the electro-optical modulator does not need to reach the terahertz frequency band, and the monitoring requirement of the terahertz channel can be met by covering the instantaneous modulation bandwidth range of communication or radar.
Example 2
A photoelectric fusion superheterodyne terahertz channel monitor for terahertz direct up-conversion optical frequency domain is shown in fig. 2, and basically comprises the following components and working processes:
the terahertz receiving unit is formed by an antenna and a power amplifier and is used for measuring terahertz signals f THz And after receiving and amplifying, the light is directly loaded on an electro-optical modulator.
Carrier frequency signal f output by frequency stabilized laser 0 And terahertz signal f THz Modulated by an electro-optical modulator to generate an optical carrier radio frequency signal f 0 +f THz And filtering out the optical carrier radio frequency signal through a band-pass optical filter and transmitting the optical carrier radio frequency signal to the photoelectric mixer.
Optical carrier radio frequency signal f 0 +f THz And swept laser outputTuning optical local oscillator signal f L The optical fibers are combined and then input into a photoelectric mixer for mixing to obtain a difference frequency signal f of the optical fibers and the photoelectric mixer L -f 0 -f THz And is input to the low-pass filter of the filtering and processing unit.
When the frequency of the difference frequency signal is within the range of the low-pass filter, a baseband signal f is output B Analog-to-digital conversion is carried out in the ADC so as to obtain the frequency f of the terahertz signal to be detected THz ＝f L -f 0 -f B The phase, the bandwidth, the signal modulation regime, the frequency shift, and the direction.
The ultra-wideband signal monitoring device has the advantage that the ultra-wideband signal monitoring from DC to terahertz frequency range can be directly covered without a terahertz local oscillator and a terahertz electric mixer.
Example 3
A multi-channel photoelectric fusion superheterodyne terahertz channel monitor, as shown in FIG. 3, basically comprises the following components and working processes:
the antenna forms a terahertz receiving unit, and the terahertz signal f to be measured THz After reception, it is directly loaded onto the electro-optic modulator.
Carrier frequency signal f output by frequency stabilized laser 0 And terahertz signal f THz Modulated by an electro-optical modulator to generate an optical carrier radio frequency signal f 0 +f THz Dividing the optical signals into n paths of optical filters which enter different band-pass ranges, and carrying out sectional monitoring on the optical carrier radio frequency signals; wherein, the 1 st channel monitors DC-f 0 +f 1 Terahertz signal in range, 2 nd channel monitoring f 0 +f 1 ～f 0 +f 2 Terahertz signal within range, … …, nth channel monitoring f 0 +f n-1 ～f 0 +f n Terahertz signals in a range. Optical carrier radio frequency signal f filtered out by band-pass optical filters of all channels 0 +f THz Tuning optical local oscillation signal f output by corresponding channel sweep laser Ln The optical fibers are combined and then input into a photoelectric mixer for mixing to obtain difference frequency signals f of the two channels Ln -f 0 -f THz And input to the low of the filtering and processing unitIn the power-on filter.
When the frequency of the difference frequency signal is within the range of the low-pass filter, a baseband signal f is output B Analog-to-digital conversion is carried out in the ADC so as to obtain the frequency f of the terahertz signal to be detected THz ＝f L -f 0 -f B Phase, bandwidth, signal modulation regime, frequency shift, direction.
The method has the advantages that the rate can be greatly improved through multi-channel segment testing, and the frequency testing coverage range can be effectively expanded.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention, and all such modifications and equivalents are intended to be encompassed in the scope of the claims of the present invention.

Claims (6)

1. The photoelectric fusion superheterodyne terahertz channel monitoring system is characterized by comprising a terahertz receiving unit, an optical carrier radio frequency unit, a tuning type optical local oscillation unit, a photoelectric down-conversion unit and a filtering and processing unit;
the terahertz receiving unit is used for receiving terahertz signals to be detected and directly loading or processing the terahertz signals to be detected and then loading the terahertz signals to the optical carrier radio frequency unit; the processing mode is amplification and/or down-conversion to an intermediate frequency, and the terahertz signal to be detected is subjected to down-conversion to the intermediate frequency to obtain an intermediate frequency signal;
the optical carrier radio frequency unit is used for loading the received terahertz signals or intermediate frequency signals onto an optical frequency domain, obtaining optical carrier radio frequency signals and transmitting the optical carrier radio frequency signals to the photoelectric down-conversion unit;
the tuning type optical local oscillation unit comprises a sweep frequency laser and is used for generating an optical local oscillation signal with tunable wavelength and transmitting the optical local oscillation signal to the photoelectric down-conversion unit;
the photoelectric down-conversion unit is used for carrying out optical frequency mixing on the optical carrier radio frequency signal and the optical local oscillation signal and down-converting the optical carrier radio frequency signal and the optical local oscillation signal to a baseband, obtaining a difference frequency signal and transmitting the difference frequency signal to the filtering and processing unit;
the filtering and processing unit is used for filtering the difference frequency signal to obtain a baseband signal, and then obtaining information of the terahertz signal to be detected through sampling and digital processing.
2. The optical-electrical fusion superheterodyne terahertz channel monitoring system according to claim 1, characterized in that said optical-carrier radio frequency unit comprises a frequency stabilization laser, an electro-optical modulator and at least one optical filter; the frequency stabilization laser is used for generating carrier frequency signals and loading the carrier frequency signals to the electro-optical modulator; the electro-optical modulator is used for receiving the carrier frequency signal and the terahertz signal or the intermediate frequency signal, and modulating to generate an optical carrier radio frequency signal; the optical filter is used for carrying out passband filtering on the optical carrier radio frequency signal.
3. The optical-electrical fusion superheterodyne terahertz channel monitoring system according to claim 2, wherein when the optical carrier radio frequency signal output by the optical carrier radio frequency unit is n paths, the number of the tuning optical local oscillation units and the optical-electrical down-conversion units is n.
4. A photo-fused superheterodyne terahertz channel monitoring system as claimed in claim 1 or 3, wherein said photo-electric down-conversion unit is a photo-electric mixer.
5. The photofusion superheterodyne terahertz channel monitoring system according to claim 4, characterized in that said filtering and processing unit comprises an electric filter and an analog-to-digital converter; the electric filter is a low-pass filter and is used for filtering the difference frequency signal to obtain a baseband signal, and inputting the baseband signal into the analog-to-digital converter for sampling and digitizing to obtain information of the terahertz signal to be detected.
6. The photofusion superheterodyne terahertz channel monitoring system of claim 4, wherein the optical filter is a bandpass filter.
CN202310175835.XA 2023-02-28 2023-02-28 Photoelectric fusion superheterodyne terahertz channel monitoring system Pending CN116170085A (en)

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CN202310175835.XA CN116170085A (en) 2023-02-28 2023-02-28 Photoelectric fusion superheterodyne terahertz channel monitoring system

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Application Number Priority Date Filing Date Title
CN202310175835.XA CN116170085A (en) 2023-02-28 2023-02-28 Photoelectric fusion superheterodyne terahertz channel monitoring system

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