CN111416577A - Millimeter wave noise signal generating device and method based on optical fiber nonlinear effect - Google Patents

Abstract

The invention discloses a millimeter wave noise signal generating device and method based on the nonlinear effect of optical fiber. The device comprises: a chaotic signal generator, a chaotic spectrum stretcher, a second optical splitter, a first programmable optical filter, a third Two programmable optical filters, optical couplers, photonic mixers, the output end of the chaotic signal generator is connected to the input end of the chaotic spectrum stretcher, and the output end of the chaotic spectrum stretcher is connected to the input end of the second optical splitter, The second optical splitter is provided with two output terminals, each output terminal is connected with a programmable optical filter, and the output terminals of the first programmable optical filter and the second programmable optical filter are connected to the optical coupler The input end of the optical coupler is connected with the input end of the photonic mixer, and the output end of the photonic mixer is used as the output end of the broadband photonic millimeter wave noise signal generating device. The invention overcomes the problems of low noise signal power and small noise signal bandwidth generated by the optical method.

Description

A device and method for generating a millimeter wave noise signal based on the nonlinear effect of optical fiber

technical field

The present invention relates to the technical field of optical fiber noise signals, and more particularly, to a device and method for generating millimeter wave noise signals based on the nonlinear effect of optical fibers.

Background technique

The nonlinear effect refers to the effect caused by the nonlinear polarization of the medium under the action of strong light, including optical harmonics, frequency doubling, stimulated Raman scattering, two-photon absorption, self-focusing, self-defocusing, etc. As an excellent transmission medium, optical fiber can also produce various complex nonlinear effects under the action of high-power optical signals, including: scattering effects (stimulated Brillouin scattering SBS and stimulated Raman scattering SRS, etc.) , Effects closely related to Kerr effect or refractive index (such as self-phase modulation SPM, cross-phase modulation XPM, four-wave mixing effect FWM), etc.

Noise, as an unavoidable source of interference, exists in various fields of the information space. Whether it is device development or system construction, in order to better control the impact of noise, noise generators are indispensable. At present, noise is mainly generated by two ways: digital synthesis and physical noise source amplification.

A noise signal generator is a special device that can generate noise in a specific frequency band, and is an important device for device parameter testing and system performance testing. The main purpose of the noise signal generator is to introduce a random signal into the system under test to simulate the noise in the actual working conditions to measure the performance of the system; to add a known noise signal and compare it with the internal noise of the system to measure the noise figure; A random signal replaces a sinusoidal or pulsed signal to test the dynamic characteristics of the system.

Millimeter-wave noise refers to noise signals in the wavelength range from 10 mm to 1 mm, or in the frequency range from 30 GHz to 300 GHz. It has good noise and gain characteristics in the mmWave frequency band. In practical applications, the millimeter-wave noise signal can be used to measure the noise figure of high-frequency instruments and components, test the signal-to-noise ratio of the radar system, and analyze the improved channel and bit error rate of the communication system.

The main problems of existing noise signal generators are: the way of noise generation by digital synthesis is mostly limited by the clock frequency of electronic devices. The noise source generated by electronic technology has a low operating frequency, and the higher the output frequency, the flatter the output noise power. The worse, the lower the super-noise ratio. The noise signal generated by the spontaneous emission of broadband light source has the problem of too low power. At present, the noise signal generated by the photon method has the disadvantages of low output power, narrow bandwidth, and difficulty in flexibly adjusting the frequency and bandwidth of the noise signal. In view of the above problems, the present invention proposes a method and device for generating a frequency-controllable and bandwidth-adjustable millimeter-wave noise signal based on the nonlinear effect of a chaotic signal.

SUMMARY OF THE INVENTION

The present invention provides a millimeter-wave noise signal generating device and method based on the nonlinear effect of optical fiber to overcome the above-mentioned defects of the noise signal generated by the spontaneous radiation of the broadband light source being too low and the bandwidth of the noise signal is small.

The primary purpose of the present invention is to solve the above-mentioned technical problems, and the technical scheme of the present invention is as follows:

A millimeter wave noise signal generating device based on the nonlinear effect of optical fiber, comprising: a chaotic signal generator, a chaotic spectrum stretcher, a second optical splitter, a first programmable optical filter, a second programmable optical filter, an optical coupling a photonic mixer, the output end of the chaotic signal generator is connected to the input end of the chaotic spectrum stretcher, and the output end of the chaotic spectrum stretcher is connected to the input end of the second optical splitter, The second optical splitter is provided with two output terminals, each output terminal is connected with the programmable optical filter, and the programmable optical filter is respectively recorded as the first programmable optical filter and the second programmable optical filter. an optical filter, the output ends of the first programmable optical filter and the second programmable optical filter are both connected to the input end of the optical coupler, and the output end of the optical coupler is mixed with the photon The input end of the photonic mixer is connected to the input end of the photonic mixer, and the output end of the photonic mixer is used as the output end of the broadband photonic millimeter wave noise signal generating device.

In this solution, the chaotic signal generator includes: a distributed feedback semiconductor laser, a polarization controller, an optical attenuator, a first optical splitter and a feedback device, and the specific connection relationship is:

The output end of the distributed semiconductor laser is connected to the input end of the polarization controller, the output end of the polarization controller is connected to the input end of the optical attenuator, and the output end of the optical attenuator is connected to the output end of the first optical splitter. an input end, the output end of the first optical splitter is respectively connected to the feedback device and the input end of the chaotic spectrum stretcher.

In this solution, the chaotic spectrum stretcher includes: a fiber amplifier and a single-mode fiber, and the specific connection relationship is that the output end of the chaotic signal generator is connected to the input end of the optical amplifier, and the output end of the optical amplifier is connected to one end of the single-mode fiber. , the other end of the single-mode fiber is connected to the input end of the second optical splitter.

In this solution, the second optical splitter, the first programmable optical filter, the second programmable optical filter, the optical coupler, and the photonic mixer constitute a two-channel chaotic signal beat frequency device, wherein the chaotic spectrum stretcher The output broadband chaotic laser signal is respectively output to the first programmable optical filter and the second programmable optical filter through the second optical splitter, and the first programmable optical filter and the second programmable optical filter The chaotic signal of the channel is subjected to wavelength selection and spectral shaping, and two channels of chaotic signals in different bands are selected, and the beat frequency is carried out through the optical coupler. and frequency-controlled millimeter-wave electrical noise.

In this solution, the center wavelengths of the first programmable optical filter and the second programmable optical filter are different, and the bandwidths can be adjusted independently.

A second aspect of the present invention provides a method for generating a millimeter-wave noise signal based on the nonlinear effect of an optical fiber. The method is applied to the device for generating a millimeter-wave noise signal based on the nonlinear effect of an optical fiber, and the method includes:

The output signal of the chaotic signal generator is input to the chaotic spectrum stretcher, and the chaotic laser signal output by the chaotic spectrum stretcher with broadband is respectively output to the first programmable optical filter and the second programmable optical filter through the second optical splitter. The first programmable optical filter and the second programmable optical filter respectively perform wavelength selection and spectral shaping on the chaotic laser signal of the channel where they are located, select two channels of chaotic signals with different wavelength bands, and perform beat frequency through the optical coupler. The frequency-reduced signal is converted from spectral to electrical spectrum through a photonic mixer, and finally output millimeter-wave electrical noise with controllable bandwidth and frequency band.

Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

The invention uses a random chaotic laser in the time domain as a signal source, and utilizes the nonlinear effect in the optical fiber to generate a high-frequency broadband photonic millimeter-wave noise signal with variable frequency and adjustable bandwidth, which effectively overcomes the optical-based method in the prior art. The problem of low noise signal power and small noise signal bandwidth generated by the noise generator.

Description of drawings

FIG. 1 is a schematic diagram of a device for generating a millimeter wave noise signal based on the nonlinear effect of an optical fiber according to the present invention.

Detailed ways

In order to understand the above objects, features and advantages of the present invention more clearly, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments may be combined with each other in the case of no conflict.

Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific details disclosed below. Example limitations.

Example 1

As shown in FIG. 1 , the present invention discloses a millimeter wave noise signal generating device based on the nonlinear effect of optical fiber. The device includes: a chaotic signal generator 1, a chaotic spectrum stretcher 2, a second optical splitter 4, a first Programmable optical filter 5, second programmable optical filter 6, optical coupler 7, photonic mixer 8, the output end of the chaotic signal generator 1 is connected with the input end of the chaotic spectral stretcher 2 , the output end of the chaotic spectrum stretcher 2 is connected to the input end of the second optical splitter 4, and the second optical splitter 4 is provided with two output ends, each output end is connected with the programmable optical filter, the programmable optical filter is respectively recorded as the first programmable optical filter 5, the second programmable optical filter 6, the first programmable optical filter 5, the second programmable optical filter 6 The output ends of the optical coupler 7 are connected to the input end of the optical coupler 7, the output end of the optical coupler 7 is connected with the input end of the photonic mixer 8, and the output end of the photonic mixer 8 is used as The output of the broadband photonic millimeter-wave noise signal generating device.

More specifically, the chaotic signal generator 1 includes: a distributed feedback semiconductor laser 101, a polarization controller 102, an optical attenuator 103, a first optical splitter 104 and a feedback device 3, and the specific connection relationship is:

The output end of the distributed semiconductor laser 101 is connected to the input end of the polarization controller 102, the output end of the polarization controller 102 is connected to the input end of the optical attenuator 103, and the output end of the optical attenuator 103 is connected to the input end of the optical attenuator 103. The input end of the first optical splitter 104, and the output end of the first optical splitter 104 is connected to the input end of the feedback device 3 and the chaotic spectral stretcher 2, respectively.

It should be noted that the external cavity feedback composed of the distributed semiconductor laser 101 and the feedback device 3 is used to generate a chaotic laser signal. The chaotic laser signal is input into the chaotic spectrum stretcher 2 .

In this solution, the chaotic spectral stretcher 2 includes: an optical amplifier 201 and a single-mode optical fiber 202. The specific connection relationship is that the output end of the chaotic signal generator 1 is connected to the input end of the optical amplifier 201, and the output end of the optical amplifier 201 is connected to To one end of the single-mode fiber 202 , the other end of the single-mode fiber 202 is connected to the input end of the second optical splitter 4 .

It should be noted that, after the chaotic laser signal is input into the chaotic spectrum stretcher 2, the chaotic laser signal is amplified by the optical amplifier 201, and the power is increased to about tens of mW. The chaotic laser signal enters the single-mode optical fiber 202 of several tens of kilometers for transmission. By adjusting the optical power of the input chaotic laser signal, the chaotic laser signal experiences the combined effect of group velocity dispersion and self-phase modulation fiber nonlinear effects in the single-mode fiber 202, and the spectrum of the input chaotic laser signal is greatly expanded in the frequency domain, while in the single-mode fiber 202 It is a chaotic random signal with no delay characteristics in the time domain.

In this scheme, the second optical splitter 4, the first programmable optical filter 5, the second programmable optical filter 6, the optical coupler 7, and the photonic mixer 8 constitute a dual-channel chaotic signal beat frequency device, The broadband chaotic laser signal output by the chaotic spectral stretcher 2 (that is, the spectrally broadened chaotic laser signal) is output to the first programmable optical filter 5 and the second programmable optical filter 6 through the second optical splitter 4, respectively. The first programmable optical filter 5 filters the spectrum of the input broadband chaotic laser signal, and flexibly selects the wavelength of the broadened spectrum and the corresponding bandwidth;

The second programmable optical filter 6 filters other parts of the broadened spectrum of the input broadband chaotic laser signal, flexibly selects the filtering wavelength and the corresponding bandwidth, and selects two chaotic laser signals with different wavelength bands.

After the spectrum regulation of the first programmable optical filter 5 and the second programmable optical filter 6, the two broadband chaotic laser signals with different wavelengths are combined by the optical coupler 7 to realize the beat frequency of the two chaotic laser signals. Through the beat frequency of two different optical signals, the signal conversion from spectrum to electric spectrum is performed, and finally, a broadband millimeter-wave noise signal with controllable frequency and bandwidth is output through the photonic mixer 8 .

It should be noted that the center wavelengths of the first programmable optical filter 5 and the second programmable optical filter 6 are different, and the bandwidths can be adjusted independently. The wavelength and chaotic laser signal bandwidth employed are related to the target mmWave noise signal generated. The wavelength interval of the two broadband chaotic laser signals determines the frequency of the millimeter-wave noise signal, and the spectral width of the two broadband chaotic laser signals determines the frequency width of the generated millimeter-wave noise signal.

A second aspect of the present invention provides a method for generating a millimeter-wave noise signal based on the nonlinear effect of an optical fiber. The method is applied to the device for generating a millimeter-wave noise signal based on the nonlinear effect of an optical fiber, and the method includes: The output signal of the chaotic signal generator 1 is input to the chaotic spectrum stretcher 2, and the chaotic laser signal with a broadband output from the chaotic spectrum stretcher 2 is output to the first programmable optical filter 5 and the second programmable optical filter 5 through the second optical splitter 4 respectively. Optical filter 6, the first programmable optical filter 5 and the second programmable optical filter 6 respectively perform wavelength selection and spectral shaping on the chaotic laser signal of the channel, and select two channels of chaotic signals with different wavebands, and pass The optical coupler 7 performs the beat frequency, and the signal after the beat frequency realizes the spectrum-electrical spectrum conversion through the photonic mixer 8, and finally outputs millimeter-wave electrical noise with controllable bandwidth and frequency band.

Compared with the noise generator based on the optical method in the prior art, the present invention uses the distributed feedback semiconductor laser as the laser source, combines feedback components, and adopts the optical feedback method to generate chaos to form a chaotic semiconductor laser. The output chaotic laser signal passes through the single-mode fiber with self-phase modulation and group velocity dispersion, and uses the nonlinear effect of the single-mode fiber to output a noise signal with a broadened spectral linewidth, a flatter noise spectrum, and a broadened power spectrum. By adjusting the wavelengths of the two filters, not only the spectral spacing between the filters can be flexibly modulated, but also the frequency of the millimeter-wave noise can be adjusted. The chaotic signals of different wavelengths are beat frequency through the photonic mixer to generate a broadband high-frequency millimeter-wave noise signal, which effectively overcomes the low noise signal power and the noise signal bandwidth generated by the noise generator based on the optical method in the prior art. small problem.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the embodiments of the present invention. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (6)

1. A millimeter wave noise signal generating device based on fiber nonlinear effect is characterized by comprising: the chaotic signal generating device comprises a chaotic signal generator (1), a chaotic spectrum stretcher (2), a second optical splitter (4), a first programmable optical filter (5), a second programmable optical filter (6), an optical coupler (7) and a photon mixer (8), wherein the output end of the chaotic signal generator (1) is connected with the input end of the chaotic spectrum stretcher (2), the output end of the chaotic spectrum stretcher (2) is connected with the input end of the second optical splitter (4), the second optical splitter (4) is provided with two output ends, each output end is connected with the programmable optical filter, the programmable optical filters are respectively marked as a first programmable optical filter (5) and a second programmable optical filter (6), the output ends of the first programmable optical filter (5) and the second programmable optical filter (6) are connected with the input end of the optical coupler (7), the output end of the optical coupler (7) is connected with the input end of the photon mixer (8), and the output end of the photon mixer (8) is used as the output end of the broadband photon millimeter wave noise signal generation device.

2. The apparatus of claim 1, wherein the chaotic signal generator comprises: distributed feedback semiconductor laser (101), polarization controller (102), optical attenuator (103), first beam splitter (104) and feedback device (3), the specific relation of connection is:

the output end of the distributed semiconductor laser (101) is connected to the input end of a polarization controller (102), the output end of the polarization controller (102) is connected to the input end of an optical attenuator (103), the output end of the optical attenuator (103) is connected to the input end of a first optical splitter (104), and the output end of the first optical splitter (104) is respectively connected to the input ends of a feedback device (3) and a chaotic spectrum stretcher (2).

3. The millimeter wave noise signal generating device based on the nonlinear effect of the optical fiber as claimed in claim 1, wherein the chaotic spectrum stretcher (2) comprises: the optical fiber amplifier comprises an optical fiber amplifier (201) and a single-mode optical fiber (202), wherein the specific connection relationship is that the output end of a chaotic signal generator (1) is connected to the input end of the optical amplifier (201), the output end of the optical amplifier (201) is connected to one end of the single-mode optical fiber (202), and the other end of the single-mode optical fiber (202) is connected to the input end of a second optical splitter (4).

4. The millimeter wave noise signal generating device based on the fiber nonlinear effect according to claim 1, wherein the second optical splitter (4), the first programmable optical filter (5), the second programmable optical filter (6), the optical coupler (7), the photon mixer (8) form a dual-channel chaotic signal beat frequency device, wherein the wide-band chaotic laser signal output by the chaotic spectrum stretcher (2) is respectively output to the first programmable optical filter (5) and the second programmable optical filter (6) through the second optical splitter (4), the first programmable optical filter (5) and the second programmable optical filter (6) respectively perform wavelength selection and spectrum shaping on the chaotic signal of the channel where the chaotic signal is located, select chaotic signals of different bands, perform beat frequency through the optical coupler (7), and the spectrum-electric spectrum conversion of the beated signal is realized through the photon mixer (8), and finally outputting millimeter wave electric noise with controllable bandwidth and frequency band.

5. The millimeter wave noise signal generating device based on the fiber nonlinear effect as claimed in claim 1, wherein the first programmable optical filter (5) and the second programmable optical filter have different center wavelengths, and the bandwidths can be adjusted independently.

6. A millimeter wave noise signal generation method based on fiber nonlinear effect, the method being applied to the millimeter wave noise signal generation device based on fiber nonlinear effect as claimed in any one of claims 1 to 5, the method comprising:

the chaotic signal generator is characterized in that an output signal of a chaotic signal generator (1) is input into a chaotic spectrum stretcher (2), the chaotic laser signal of a broadband output by the chaotic spectrum stretcher (2) is respectively output to a first programmable optical filter (5) and a second programmable optical filter (6) through a second optical splitter (4), the first programmable optical filter (5) and the second programmable optical filter (6) respectively perform wavelength selection and spectrum shaping on the chaotic laser signal of a channel where the chaotic laser signal is located, two paths of chaotic signals of different wave bands are selected, beat frequency is performed through an optical coupler (7), the signal after beat frequency realizes spectrum-electric spectrum conversion through a photon frequency mixer (8), and finally millimeter wave electric noise with controllable bandwidth and frequency band is output.

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