阅读说明：本技术 一种宽带噪声源的产生装置及其信号产生方法 (Broadband noise source generating device and signal generating method thereof ) 是由 高震森 王云才 秦玉文 孙粤辉 郭亘立 于 2019-10-18 设计创作，主要内容包括：本发明公开了一种宽带噪声源的产生装置及其信号产生方法，通过利用随机激光器作为宽带噪声源，由于其发光原理来自放大的自发辐射，光谱带宽远大于普通激光光源，在保证输出信号的随机类噪声特征的情况下，实现了宽带的信号输出，且输出噪声信号超噪比达到20dB，显著提升噪声发生器的输出带宽和输出功率；设置滤波整形模块对随机激光器输出的光谱进行精确整形，消除光谱中的发射峰，使得转化后的频谱的平坦度不大于±6dB；同时已知最后得到频谱的形状为光谱形状的自卷积，通过对光谱进行滤波，可得到能量分布符合标准高斯分布的光谱，使得最终得到的频谱更加平滑，再配合光放大器和光衰减器，使输出的噪声信号幅度连续可调谐。(The invention discloses a generating device of a broadband noise source and a signal generating method thereof.A random laser is used as the broadband noise source, and the light-emitting principle of the random laser is from amplified spontaneous radiation, so that the spectral bandwidth is far greater than that of a common laser light source, the signal output of the broadband is realized under the condition of ensuring the random noise characteristics of the output signal, the output noise signal is up to 20dB in over-noise ratio, and the output bandwidth and the output power of the noise generator are obviously improved; a filter shaping module is arranged to accurately shape the spectrum output by the random laser, and an emission peak in the spectrum is eliminated, so that the flatness of the converted spectrum is not more than +/-6 dB; meanwhile, the shape of the finally obtained spectrum is known as the self-convolution of the spectrum shape, the spectrum with the energy distribution conforming to the standard Gaussian distribution can be obtained by filtering the spectrum, so that the finally obtained spectrum is smoother, and the amplitude of the output noise signal can be continuously tunable by matching with an optical amplifier and an optical attenuator.)

1. The broadband noise source generating device is characterized by comprising a random laser (1), a filter shaping module (2), an optical amplifier (3), an optical attenuator (4) and a photoelectric detector (5), wherein the output end of the random laser (1) is connected with the input end of the filter shaping module (2), the output end of the filter shaping module (2) is connected with the input end of the optical amplifier (3), the output end of the optical amplifier (3) is connected with the input end of the optical attenuator (4), the output end of the optical attenuator (4) is connected with the input end of the photoelectric detector (5), and the output end of the photoelectric detector (5) is used as the output end of the broadband noise source generating device.

2. The generation device of a broadband noise source according to claim 1, wherein said filter shaping module (2) comprises a circulator (211), a first concave lens (212), a second concave lens (214), a grating (213), a liquid crystal on silicon optical processor (215); an optical signal output by the random laser (1) enters a first concave lens (212) through an input end of a circulator (211), the incident optical signal is reflected on a grating (213) through the first concave lens (212) and is subjected to dispersion on the grating (213), optical signals in multiple directions obtained after dispersion are converted into parallel light through a second concave lens (214) and are reflected to enter a silicon-based liquid crystal optical processor (215) for filtering and shaping, and the filtered and shaped optical signal returns to the circulator (211) along an original optical path and is emitted through an output end of the circulator (211); the input end of the circulator (211) is used as the optical signal input end of the filter shaping module (2); and the output end of the circulator (211) is used as the optical signal output end of the filter shaping module (2).

3. A broadband noise source generating device according to claim 2, wherein said liquid crystal on silicon optical processor (215) comprises a reflective matrix liquid crystal cell for adding a separate phase shift to the incoming optical signal, thereby controlling each wavelength of the optical signal independently of all other wavelengths without mutual interference between the wavelengths.

4. The broadband noise source generation device according to claim 1, wherein the filter shaping module (2) comprises an optical signal input end, a first convex lens (221), ten transmissive F-P interferometers (222), a second convex lens (223), and an optical signal output end, which are arranged in sequence; an optical signal output by the random laser (1) enters the first convex lens (221) through an optical signal input end, the optical signal is collimated by the first convex lens (221), then is subjected to filtering shaping sequentially through the ten transmission type F-P interferometers (222), and the optical signal subjected to filtering shaping is combined through the second convex lens (223) and then is output to the filtering shaping module (2) through the optical signal output end.

5. A generation device of a broadband noise source according to claim 1, characterized in that the mechanism of said random laser (1) is amplification of spontaneous emissions in a gain medium.

6. The broadband noise source generation method based on the broadband noise source generation device according to any one of claims 1 to 5, wherein the random laser (1) emits laser light under a weak scattering condition, enters the filter shaping module (2) to perform spectral filter shaping to obtain an optical signal having a smooth spectrum and a standard Gaussian energy distribution, the optical signal enters the optical amplifier (3) to be amplified and then enters the optical attenuator (4), the optical attenuator (4) controls the optical signal power, and the output of the optical attenuator (4) enters the photoelectric detector (5) to perform spectral and spectral conversion so as to output a broadband electrical noise signal.

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a device and a method for generating a broadband noise source.

Background

The noise generator is a device capable of generating noise in a specific frequency band, the output power of the noise generator is continuously controllable, the noise power spectral density is uniform and flat, and the noise generator is an essential test instrument for measuring the noise coefficient. By inputting precisely known noise into a device, a module or a system to be tested, the sensitivity of a receiver can be measured, the performance of an antenna can be evaluated, the parameters of an amplifier can be analyzed, the output of a radiometer can be calibrated, the anti-interference capability of a radar can be checked and the like, so that the noise generator is a special scientific instrument which has important applications in various fields such as communication, remote sensing, military, astronomy and the like.

Existing noise generators are classified into a noise generator using an electronic device as a signal source and a noise generator using spontaneous emission optical noise amplified in an erbium-doped fiber amplifier as a physical entropy source.

At present, the main problems of the noise generator based on the electronic device are as follows: the noise generator using resistance thermal noise as a source needs refrigeration, has large volume, small output power and difficult coupling, and is not suitable for airborne spaceborne; the noise generator with the diode as the source has an operating frequency less than 170GHz, and the flatness of the output noise is deteriorated along with the frequency increase, so that the bandwidth of the final output noise is narrowed; the noise generator using the field effect transistor as a source has low equivalent output noise temperature, which means that the output noise power is low and the ultra-noise ratio is low, so that the use requirement of the noise generator cannot be met; the noise generator using the spontaneous radiation light amplified in the erbium-doped fiber amplifier as a source has low power of generated optical noise, and the power is smaller after filtering, so that the noise generator is difficult to use practically. The spontaneous radiation noise spectrum is filtered by an optical filter with the line width of 100GHz in an experiment, and the optical power is found to be attenuated by 30dB, so that the power requirement of a noise generator cannot be met.

In summary, the noise power output by the existing noise generator cannot meet the power requirement of the noise generator, and the practicability is low.

Disclosure of Invention

The invention provides a device for generating a broadband noise source and a signal generating method thereof, aiming at solving the problem that the noise power output by the existing noise generator can not meet the power requirement of the noise generator.

In order to achieve the above purpose, the technical means adopted is as follows:

the output end of the random laser is connected with the input end of the filter shaping module, the output end of the filter shaping module is connected with the input end of the optical amplifier, the output end of the optical amplifier is connected with the input end of the optical attenuator, the output end of the optical attenuator is connected with the input end of the photoelectric detector, and the output end of the photoelectric detector is used as the output end of the broadband noise source generating device.

In the scheme, the random laser is used as a broadband noise source, the light emitting principle of the random laser is from amplified spontaneous radiation, the spectral bandwidth is far larger than that of a common laser light source, the broadband signal output is realized under the condition that the random noise characteristics of the output signal are ensured, the output noise signal is up to 20dB in super-noise ratio, and the output bandwidth and the output power of the noise generator are obviously improved; a filter shaping module is arranged to accurately shape the spectrum output by the random laser, and an emission peak in the spectrum is eliminated, so that the flatness of the converted spectrum is not more than +/-6 dB; meanwhile, the shape of the finally obtained spectrum is known as the self-convolution of the spectrum shape, the spectrum with the energy distribution conforming to the standard Gaussian distribution can be obtained by filtering the spectrum, so that the finally obtained spectrum is smoother, and the amplitude of the output noise signal can be continuously tunable by matching with an optical amplifier and an optical attenuator.

Preferably, the filter shaping module comprises a circulator, a first concave lens, a second concave lens, a grating and a silicon-based liquid crystal optical processor; an optical signal output by the random laser enters the first concave lens through the input end of the circulator, the incident optical signal is reflected on the grating through the first concave lens and is subjected to chromatic dispersion on the grating, the optical signal in multiple directions obtained after chromatic dispersion is converted into parallel light through the second concave lens and is reflected to enter the silicon-based liquid crystal optical processor for filtering and shaping, and the optical signal after filtering and shaping returns to the circulator along an original optical path and is emitted through the output end of the circulator; the input end of the circulator is used as the optical signal input end of the filtering and shaping module; and the output end of the circulator is used as the optical signal output end of the filtering and shaping module.

Preferably, the LCOS optical processor includes a reflective matrix liquid crystal cell for adding individual phase shifts to the incoming optical signal, thereby controlling each wavelength of the optical signal independently of all other wavelengths without mutual interference between the wavelengths.

Preferably, the filter shaping module comprises an optical signal input end, a first convex lens, ten transmissive F-P interferometers, a second convex lens and an optical signal output end which are sequentially arranged; and an optical signal output by the random laser enters the first convex lens through an optical signal input end, the optical signal is collimated by the first convex lens and then is filtered and shaped sequentially through the ten transmission type F-P interferometers, and the filtered and shaped optical signal is output by the filtering and shaping module through the optical signal output end after being combined through the second convex lens. In the preferred scheme, the bandwidth and the flatness of the transmission spectrum are optimized by adjusting the cavity length of each transmission type F-P interferometer, so that the input optical signal is precisely filtered and shaped.

Preferably, the mechanism of the random laser is amplification of spontaneous emission in the gain medium. In the preferred embodiment, the random laser emits laser light under weak scattering condition, and because the phase of the photons of the random laser cannot be maintained in the scattering process, the emitted laser light is essentially amplified spontaneous radiation, and the spectral distribution of the emitted laser light deviates from standard Gaussian distribution. The random laser utilizes random optical feedback to form a random resonant cavity, replaces an optical resonant cavity in the traditional laser, has randomness in the frequency and the intensity of laser emitted, and is more suitable for being used as a signal source of a noise generator.

The invention also provides a broadband noise source generating method based on the broadband noise source generating device, the random laser emits laser under the weak scattering condition, the laser enters the filter shaping module to carry out filter shaping of the spectrum, an optical signal with smooth spectrum and standard Gaussian distribution of energy distribution is obtained, the optical signal is input into the optical amplifier to be amplified and then enters the optical attenuator, the power of the optical signal is controlled by the optical attenuator, and the output of the optical attenuator enters the photoelectric detector to carry out spectrum and electric spectrum conversion so as to output a broadband electric noise signal.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

the random laser is used as a broadband noise source, the light emitting principle of the random laser is from amplified spontaneous radiation, the spectral bandwidth is far larger than that of a common laser light source, the broadband signal output is realized under the condition of ensuring the random noise characteristics of the output signal, the output noise signal ultra-noise ratio reaches 20dB, and the output bandwidth and the output power of the noise generator are obviously improved; a filter shaping module is arranged to accurately shape the spectrum output by the random laser, and an emission peak in the spectrum is eliminated, so that the flatness of the converted spectrum is not more than +/-6 dB; meanwhile, the shape of the finally obtained spectrum is known as the self-convolution of the spectrum shape, the spectrum with the energy distribution conforming to the standard Gaussian distribution can be obtained by filtering the spectrum, so that the finally obtained spectrum is smoother, and the amplitude of the output noise signal can be continuously tunable by matching with an optical amplifier and an optical attenuator.

The broadband noise source provided by the invention solves the problem that the noise power output by the existing noise generator can not meet the power requirement of the noise generator, and meanwhile, as the broadband noise source provided by the invention consists of the photonic devices, the broadband noise source has the advantages of less heating, small volume, easiness in coupling and convenience for using various carriers.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic structural diagram of a filter shaping module in embodiment 1.

Fig. 3 is a schematic structural diagram of a filter shaping module in embodiment 2.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the patent;

for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product;

it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.