Multiband reconfigurable fourier mode-locked optoelectronic oscillator

Abstract

The present application relates to a kind of multi-band reconfigurable fourier mode-locked optoelectronic oscillator, its structure includes laser, electro-optic modulator, photodetector, first A low noise amplifier, first multiplexer, second multiplexer, filter amplification branch, arbitrary waveform generator and electric power divider etc., wherein, first multiplexer, second multiplexer, the N filter amplification branches connected therebetween and arbitrary waveform generator jointly constitute multi-band reconfigurable filter module.The present application sets up multiple filter amplification branches in optoelectronic feedback oscillation loop, thereby constructs a multi-band fourier mode-locked oscillation loop cavity, the frequency range and period of multi-band reconfigurable microwave signal are determined by the sweep width and period of tunable filter in each filter amplification branch in multi-band reconfigurable filter module.Thereby for anti-radar or anti-jamming communication system provides a high-quality microwave signal source.

Description

TECHNICAL FIELD

[0001] The present application relates to a microwave photon device, in particular to a multi-band reconfigurable Fourier mode-locked optoelectronic oscillator. BACKGROUND

[0002] Multi-band, reconfigurable low phase noise microwave source is the core component of communication, radar and electronic measurement system. Modern radar, mobile communication and other microwave systems have gradually developed from single frequency band to multi-band and reconfigurable. For example, the next generation of mobile communication system will work in three different frequency bands (K band, Ka band and U band), and the radio frequency source needs to have the function of fast switching or simultaneous working in these three frequency bands. Modern radar systems, including reconnaissance, detection, jamming, communication and other functions, have different working frequency bands, instantaneous bandwidths, coding forms, etc. However, the traditional electronic technology is difficult to meet the needs of modern mobile communication, radar, electronic countermeasure and other microwave systems in integration, software definition and other aspects in terms of instantaneous bandwidth reconfigurability.

[0003] Microwave photonics technology breaks through the technical bottleneck of traditional electronic means, has the technical advantages of large bandwidth, low loss, fast reconfiguration and anti-electromagnetic interference, and has been widely studied in recent years. Fourier mode-locked tunable optoelectronic oscillator (FDML-OEO) technology replaces the narrowband RF filter of the optoelectronic oscillator (OEO) with a frequency-sweeping filter, and synchronizes the frequency-sweeping period of the filter with the ring cavity delay of the OEO to realize the frequency domain mode-locked state, so that all modes in the frequency-sweeping range of the OEO oscillate in the ring cavity at the same time, thereby breaking through the limitation of mode establishment time in the traditional OEO. At present, based on FDML OEO, single linear frequency modulation and double chirp microwave signals have been successfully generated. However, how to realize the generation of fast, wideband reconfigurable multi-band microwave signals based on Fourier mode-locked optoelectronic oscillator technology has not been effectively solved. SUMMARY

[0004] The purpose of the present application is to provide a multi-band reconfigurable Fourier mode-locked optoelectronic oscillator to solve the problem that the existing Fourier mode-locked optoelectronic oscillator cannot generate fast, wideband reconfigurable multi-band microwave signals.

[0005] The purpose of the present application is achieved as follows:

[0006] A multi-band reconfigurable Fourier mode-locked optoelectronic oscillator comprises:

[0007] A laser is connected to the optical carrier input end of the electro-optical modulator through an optical fiber, and is used to provide an optical carrier signal;

[0008] An electro-optical modulator, whose optical carrier output end is connected to the input end of a photoelectric detector through a long delay optical fiber, for intensity modulation of the input optical carrier signal and loading of a microwave signal onto the optical carrier signal; the long delay optical fiber is used for delaying the optical carrier signal output by the electro-optical modulator;

[0009] A photoelectric detector, whose output end is connected to the input end of a first low noise amplifier, for converting the input optical carrier signal into a microwave electrical signal for output;

[0010] The first low noise amplifier, whose output end is connected to the input end of a first multiplexer, is used for amplifying the microwave electrical signal output by the photoelectric detector and the feedback microwave electrical signal received by the system, to compensate for the loss of the oscillation loop;

[0011] The first multiplexer, as the signal input end of the multi-band reconfigurable filter module, is used for connecting the input ends of the two filter amplification branches;

[0012] The second multiplexer, as the signal output end of the multi-band reconfigurable filter module, is used for connecting the output ends of the two filter amplification branches; the output of the second multiplexer is connected to the input end of an electrical power divider;

[0013] The filter amplification branches, at least three, each is composed of a wideband filter, a tunable filter and a low noise amplifier connected in series, for filtering and selecting the mode of the input microwave electrical signal of the multi-band reconfigurable filter module;

[0014] The arbitrary waveform generator, having at least three synchronous channels, each channel is connected to the control end of the tunable filter in a filter amplification branch, for configuring the passband of the tunable filter in each filter amplification branch, to perform periodic output of definable multiple frequencies;

[0015] The electrical power divider, one of its output ends is used for outputting the obtained microwave signal, and the other output end is connected to the radio frequency port of the electro-optical modulator, for transmitting the obtained microwave electrical signal to the electro-optical modulator, to form an optical-electric feedback oscillation loop.

[0016] Further, the working conditions of each filter amplification branch are that the working bands of the wideband filter and the tunable filter in each filter amplification branch are the same, but the working bands of the filter amplification branches are different.

[0017] Further, the conditions for the optical-electric oscillator to realize Fourier domain mode locking are that the tuning periods of the tunable filters in the filter amplification branches are respectively integer multiples of the delay time of one round of signal transmission in the oscillation loop.

[0018] The purpose of the present application can also be achieved as follows:

[0019] A multi-band reconfigurable Fourier mode-locked optoelectronic oscillator comprises:

[0020] A laser is connected to an optical carrier input end of an electro-optical modulator through an optical fiber for providing an optical carrier signal;

[0021] An electro-optical modulator is connected to an input end of a photoelectric detector through a long optical fiber for intensity modulation of the input optical carrier signal and loading of a microwave signal onto the optical carrier signal; the long optical fiber is used for time delay of the optical carrier signal output by the electro-optical modulator;

[0022] A photoelectric detector is connected to an input end of a first low noise amplifier for conversion of the input optical carrier signal into a microwave electrical signal for output;

[0023] The first low noise amplifier is connected to an input end of a first diplexer for amplification of the microwave electrical signal output by the photoelectric detector and a feedback microwave electrical signal received by the system to compensate for loss of an oscillation loop;

[0024] The first diplexer is used as a signal input end of a dual-band reconfigurable filter module for connection of input ends of two filter amplification branches;

[0025] A second diplexer is used as a signal output end of the dual-band reconfigurable filter module for connection of output ends of the two filter amplification branches; an output of the second diplexer is connected to an input end of an electrical power divider;

[0026] The filter amplification branches are two, each of which is composed of a wideband filter, a tunable filter and a low noise amplifier connected in series for filtering and mode selection of the microwave electrical signal input into the dual-band reconfigurable filter module;

[0027] An arbitrary waveform generator has at least two synchronous channels, each of which is connected to a control end of the tunable filter in one of the filter amplification branches for configuration of passbands of the tunable filters in the two filter amplification branches to perform periodic output of definable dual frequencies;

[0028] The electrical power divider has one output end for output of the obtained microwave signal and another output end connected to a radio frequency port of the electro-optical modulator for transmission of the obtained microwave electrical signal to the electro-optical modulator to form an optoelectronic feedback oscillation loop.

[0029] Further, the working conditions of the two filter amplification branches are that the wideband filter and the tunable filter in each of the filter amplification branches have the same working band, but the working bands of the filter amplification branches are different.

[0030] Further, the condition for the optoelectronic oscillator to realize Fourier domain mode locking is that the tuning periods of the tunable filters in the two filter-amplifier branches are integer times of the time delay of the signal transmitting one round in the oscillation loop.

[0031] The present application sets two or more filter-amplifier branches in the optoelectronic feedback oscillation loop, thereby constructing a multi-band Fourier mode-locked oscillation loop cavity, and uses an arbitrary waveform generator to apply the required waveform of the driving signal to each filter-amplifier branch, thereby forming a multi-band reconfigurable filter module. After the signal transmitted in the optoelectronic oscillator loop cavity transmits one round in the loop, it returns to the position of the tunable filter in each branch of the multi-band reconfigurable filter module, and the passband of the tunable filter in each branch is tuned to the same position, so that all the signals transmitted in the loop can oscillate in the loop. When the gain of the optoelectronic oscillator optoelectronic feedback oscillation loop is greater than the loss, multiple-band definable microwave signals can be generated by self-oscillation in the loop. The frequency range and period of the multi-band reconfigurable microwave signal are determined by the sweep width and period of the tunable filter in each filter-amplifier branch in the multi-band reconfigurable filter module.

[0032] The optoelectronic oscillator of the present application has the advantage of low phase noise, and the microwave signal generated based on the principle of the optoelectronic oscillator can realize flexible definition and tuning of the multi-band output signal by controlling the frequency scanning range, scanning mode, scanning period, etc. of the multiple tunable filters, and has the characteristics of multiple wideband, frequency agility, simple adjustment method, etc. The optoelectronic oscillator of the present application can generate wideband, multi-band, reconfigurable and arbitrarily defined microwave signals without the aid of high-speed electronic devices, and provides a high-quality microwave signal source for counter-radar or anti-jamming military communication systems. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural block diagram of Example 1.

[0034] Figure 2 is a structural block diagram of a ring resonant tunable RF filter.

[0035] Figure 3 is a schematic diagram of the instantaneous frequency of a double-band reconfigurable microwave signal.

[0036] Figure 4 is a structural block diagram of Example 2.

[0037] In the diagram: 1. Laser, 2. Electro-optic modulator, 3. Long-delay fiber, 4. Photodetector, 5. Low-noise amplifier A, 6. First duplexer, 7. First broadband filter, 8. First tunable filter, 9. First low-noise amplifier, 10. Second broadband filter, 11. Second tunable filter, 12. Second low-noise amplifier, 13. Second duplexer, 14. Arbitrary waveform generator, 15. Dual-band reconfigurable filter module, 16. Power divider, 17. First multiplexer, 18. Second multiplexer, 19. Nth broadband filter, 20. Nth tunable filter, 21. Nth low-noise amplifier, 22. Multi-band reconfigurable filter module. Detailed Implementation

[0038] Example 1: Dual-band reconfigurable Fourier mode-locked optoelectronic oscillator.

[0039] like Figure 1 As shown, the system configuration of the photoelectric oscillator of the present invention is as follows: The laser emitting end of the laser 1 is connected to the optical carrier input end of the electro-optic modulator 2 via an optical fiber to provide an optical carrier signal for the system. The optical carrier output end of the electro-optic modulator 2 is connected to the input end of the photodetector 4 via a delay-length optical fiber 3 to intensity modulate the optical carrier signal input to the electro-optic modulator 2 and load a microwave signal onto the optical carrier signal. The delay-length optical fiber 3 delays the optical carrier signal output by the electro-optic modulator 2. The output end of the photodetector 4 is connected to the input end of the Ath low-noise amplifier 5 to convert the input optical carrier signal into a microwave electrical signal and output it to the Ath low-noise amplifier 5. The output end of the Ath low-noise amplifier 5 is connected to the input end of the first duplexer 6 to amplify the microwave electrical signal output by the photodetector 4 and the feedback microwave electrical signal received by the system to compensate for the loss of the oscillation loop. The first duplexer 6 serves as the signal input end of the dual-band reconfigurable filter module 15 and is used to connect the input ends of the two filtering and amplification branches. The second duplexer 13 serves as the signal input terminal of the dual-band reconfigurable filter module 15, and is used to connect the output terminals of the two filtering and amplification branches.

[0040] There are two filtering and amplification branches. The first branch consists of a first wideband filter 7, a first tunable filter 8, and a first low-noise amplifier 9 connected in series. The second branch consists of a second wideband filter 10, a second tunable filter 11, and a second low-noise amplifier 12 connected in series. The arbitrary waveform generator 14 has at least two synchronization channels, each connected to the control terminal of a tunable filter in one of the filtering and amplification branches. These channels are used to configure the passbands of the tunable filters in the two filtering and amplification branches to achieve a definable dual-frequency periodic output.

[0041] The first tunable filter 8 and the second tunable filter 11 are tunable filters with fast tuning narrow band pass, and can be ring resonant tunable RF filters, yttrium iron garnet (YIG) filters, or other types of microwave filters with the same effect. Figure 2 In the ring resonant tunable RF filter shown, the electric phase shifter is controlled by the phase output of the voltage control signal from the arbitrary function generator 14, so that the tuning change of the center frequency of the ring resonant tunable RF filter can be controlled.

[0042] The first duplexer 6, the second duplexer 13, the two filter amplification branches connected therebetween, and the arbitrary wave generator 14 jointly constitute a dual-band reconfigurable filter module 15. In the dual-band reconfigurable filter module 15, the working conditions of the two filter amplification branches are that the wideband filter and the tunable filter in each filter amplification branch have the same working wave band, but the working wave bands of the filter amplification branches are different, so that the microwave telecommunication signal input into the dual-band reconfigurable filter module 15 can be filtered and selected.

[0043] The output of the second duplexer 13 is connected to the input of an electric power divider 16. One output of the electric power divider 16 is used as a system output end to output the microwave signal obtained by the system, and the second output of the electric power divider 16 is connected to the radio frequency port of the electro-optical modulator 2 to transmit the obtained microwave telecommunication signal to the electro-optical modulator 2. In this way, through the connection of the dual-band reconfigurable filter module 15 and the electric power divider 16 and the connection of the electric power divider 16 and the electro-optical modulator 2, the system forms an opto-electric feedback oscillation loop.

[0044] The working process of the embodiment is as follows: the laser signal output by the laser 1 enters the electro-optical modulator 2 to be intensity modulated, then enters the optical delay fiber 3 for delay, and then enters the photoelectric detector 4 to be opto-electrically converted, and then enters the first A low noise amplifier 5 to be signal amplified, and then the output signal enters the dual-band reconfigurable filter module 15 to be synchronously selected at two different frequencies. Through the control of the amplitude and period of the signal generated by the arbitrary function generator 14, the pass bands of the two tunable filters in the dual-band reconfigurable filter module 15 can be flexibly configured, so that the periodic output of the two definable frequencies can be performed. When the periods of the two tunable filters 8 and 11 are adjusted to be equal to the integer times of the delay of the fiber delay loop, the Fourier domain mode locking of the opto-electric oscillator of the embodiment can be realized. At this time, the opto-electric oscillator of the embodiment can output the microwave signal with reconfigurable frequency in the dual-band range, and the bandwidth and frequency of the dual-frequency signal output by the system are determined by the tuning range of the two tunable filters 8 and 11 in the dual-band reconfigurable filter module 15.

[0045] The frequency of the passband response of the tunable filter is changed by adjusting the voltage amplitude of the driving signal of the two tunable filters 8 and 11, so that the tunable filter is tuned according to the set rule, thereby realizing the real-time tunable filtering. When the microwave signal is modulated by the electro-optical modulator 2 and transmitted through the optical link and returned to the tunable filter, if the passband frequency of the tunable filter is consistent with the signal frequency, the Fourier domain mode-locked optoelectronic oscillator is realized at this time. At this time, the dual-band reconfigurable Fourier mode-locked optoelectronic oscillator outputs the low phase noise microwave signal in the dual-band which can be defined arbitrarily, and the frequency of the signal is determined by the waveform of the driving signal of the two tunable filters 8 and 11.

[0046] In order to realize the Fourier domain mode-locked optoelectronic oscillator, the time for the signal to be transmitted in the ring cavity of the optoelectronic oscillator for one cycle should be strictly equal to an integer multiple of the period of the generated signal, that is:

[0047] n T i T r

[0048] wherein n is a positive integer, T i is the tuning period of the tunable filter in the filter amplification branch i in the dual-band reconfigurable filter module 15, T r is the delay time for the signal to be transmitted in the ring of the optoelectronic oscillator for one cycle.

[0049] In other words, the condition for the Fourier domain mode-locked optoelectronic oscillator is that the tuning period of the tunable filter in the two filter amplification branches is an integer multiple of the delay time for the signal to be transmitted in the ring for one cycle.

[0050] Figure 3 The instantaneous frequency diagram of the dual-band frequency coded microwave signal output by the dual-band reconfigurable Fourier mode-locked optoelectronic oscillator is given. Figure 3 It can be seen that the optoelectronic oscillator can be used to realize the multi-band microwave signal with definable output frequency.

[0051] Embodiment 2: Multi-band reconfigurable Fourier mode-locked optoelectronic oscillator.

[0052] The first duplexer 6 and the second duplexer 13 in embodiment 1 are expanded into multi-plexers, and a plurality of filter amplification branches are connected in parallel between the two multi-plexers, each branch has a different working band, such as S-band, X-band, Ku-band, K-band, etc., and the arbitrary function generator 14 has a corresponding number of synchronous channels, and simultaneously controls the simultaneous output of signals with different frequencies in each band. The optoelectronic oscillator with this structure can form a multi-band reconfigurable Fourier mode-locked optoelectronic oscillator.​

[0053] like Figure 4 As shown, the system configuration of the photoelectric oscillator of the present invention is as follows: the laser emitting end of the laser 1 is connected to the optical carrier input end of the electro-optic modulator 2 via an optical fiber; the optical carrier output end of the electro-optic modulator 2 is connected to the input end of the photodetector 4 via a delay-length optical fiber 3; the delay-length optical fiber 3 delays the optical carrier signal output by the electro-optic modulator 2. The output end of the photodetector 4 is connected to the input end of the Ath low-noise amplifier 5, and the output end of the Ath low-noise amplifier 5 is connected to the input end of the first multiplexer 17, which amplifies the microwave signal output by the photodetector 4 and the feedback microwave signal received by the system to compensate for the loss of the oscillation loop. The first multiplexer 17 serves as the signal input end of the multi-band reconfigurable filter module 22, and is used to connect the input ends of N filter amplification branches. The second multiplexer 18 serves as the signal input end of the multi-band reconfigurable filter module 22, and is used to connect the output ends of N filter amplification branches.

[0054] There are N filtering and amplification branches. The first branch consists of a first wideband filter 7, a first tunable filter 8, and a first low-noise amplifier 9 connected in series. The second branch consists of a second wideband filter 10, a second tunable filter 11, and a second low-noise amplifier 12 connected in series, and so on. The Nth branch consists of an Nth wideband filter 19, an Nth tunable filter 20, and an Nth low-noise amplifier 21 connected in series. The arbitrary waveform generator 14 has N synchronization channels, each connected to the control terminal of a tunable filter in one of the filtering and amplification branches. These channels are used to configure the passbands of the tunable filters in the two filtering and amplification branches to achieve a definable multi-frequency periodic output.

[0055] The tunable filters in each filtering and amplification branch are all tunable filters with fast tuning narrow bandpass, and can be ring resonant tunable RF filters, yttrium iron garnet (YIG) filters, or other types of microwave filters with the same effect.

[0056] The first multiplexer 17, the second multiplexer 18, the N filtering and amplification branches connected thereto, and the arbitrary waveform generator 14 together constitute the multi-band reconfigurable filter module 22. In the multi-band reconfigurable filter module 22, the operating conditions of each filtering and amplification branch are: the broadband filter in each filtering and amplification branch operates in the same band as the tunable filter, but the operating bands of each filtering and amplification branch are different, thus enabling filtering and mode selection of the microwave electrical signal input to the multi-band reconfigurable filter module 22.

[0057] The output of the second multiplexer 18 is connected to the input of the electrical power divider 16. One output of the electrical power divider 16 is used as the system output, outputting the microwave signal obtained by the system; the second output of the electrical power divider 16 is connected to the RF port of the electro-optical modulator 2, used to transmit the obtained microwave electrical signal to the electro-optical modulator 2. In this way, through the connection of the multi-band reconfigurable filter module 22 and the electrical power divider 16, and the connection of the electrical power divider 16 and the electro-optical modulator 2, the system forms an opto-electric feedback oscillation loop.

[0058] The working process of the embodiment is basically the same as that of the embodiment, and the condition for the opto-electric oscillator to realize Fourier domain mode locking is that the tuning periods of the tunable filters in each filter amplification branch are respectively integer multiples of the time delay of one round of signal transmission in the oscillation loop.

Claims

1. A multi-band reconfigurable Fourier mode-locked optoelectronic oscillator, characterized in that, The application relates to an optical-electric oscillator for realizing Fourier domain mode locking, which comprises the following parts: a laser connected with an optical carrier input end of an electro-optical modulator through an optical fiber, used for providing an optical carrier signal; an electro-optical modulator, whose optical carrier output end is connected with an input end of a photoelectric detector through a long delay optical fiber, used for intensity modulating the input optical carrier signal and loading a microwave signal on the optical carrier signal; the long delay optical fiber is used for delaying the optical carrier signal output by the electro-optical modulator; a photoelectric detector, whose output end is connected with an input end of a first low noise amplifier, used for converting the input optical carrier signal into a microwave electric signal and outputting the microwave electric signal; the first low noise amplifier, whose output end is connected with an input end of a first diplexer, used for amplifying the microwave electric signal output by the photoelectric detector and a feedback microwave electric signal received by the system, so as to compensate the loss of the oscillation loop; the first diplexer, used as a signal input end of a double-waveband reconfigurable filter module, used for connecting input ends of two filter amplification branches; a second diplexer, used as a signal output end of the double-waveband reconfigurable filter module, used for connecting output ends of the two filter amplification branches; an output end of the second diplexer is connected with an input end of an electric power divider; the filter amplification branches, two in number, each of which is composed of a wideband filter, a tunable filter and a low noise amplifier connected in sequence, used for filtering and selecting the microwave electric signal input by the double-waveband reconfigurable filter module; the working conditions of the two filter amplification branches are that the working wavebands of the wideband filter and the tunable filter in each filter amplification branch are the same, but the working wavebands of the filter amplification branches are different; an arbitrary waveform generator, having at least two synchronous channels, each of which is connected with a control end of the tunable filter in one filter amplification branch, used for configuring the passband of the tunable filter in the two filter amplification branches, so as to periodically output the definable double frequency; the electric power divider, one output end of which is used for outputting the obtained microwave signal, and the other output end of which is connected with a radio frequency port of the electro-optical modulator, used for transmitting the obtained microwave electric signal to the electro-optical modulator, so as to form an optical-electric feedback oscillation loop.

2. The multi-octave reconfigurable Fourier mode-locked opto-electronic oscillator of claim 1, wherein, The condition for realizing Fourier domain mode locking by the optical-electric oscillator is that the tuning periods of the tunable filters in the two filter amplification branches are respectively integer times of the time delayed by the signal in one round of transmission in the oscillation loop.

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