A multi-channel broadband chaotic laser generator based on a micro-ring resonator

Abstract

The present invention belongs to the field of communications technology, specifically relating to a multi-channel broadband chaotic laser generator based on a microring resonator. The device comprises a distributed feedback semiconductor laser, a polarization controller, an adjustable optical attenuator, a microring resonator, a fiber optic reflector, and a wavelength division multiplexer. The device is characterized in that the distributed feedback semiconductor laser, polarization controller, adjustable optical attenuator, and the fiber optic reflector at the through-end of the microring resonator form a feedback loop to generate an initial chaotic laser. After the initial chaotic laser is injected into the microring resonator, it undergoes a combination of four-wave mixing, self-phase modulation, cross-phase modulation, and dispersion. After being output from the downstream end of the microring resonator, it generates a chaotic optical frequency comb with multiple comb teeth. Wavelength division multiplexing (WDM) technology can then be used to generate multi-channel, high-bandwidth chaotic signals. This invention addresses the lack of solutions for implementing multi-channel broadband chaotic lasers and can be applied to secure communications, radar ranging, random number generation, and other fields.

Description

Technical Field

[0001] The present invention relates to a multi-path broadband chaotic laser generating device based on a micro-ring resonator, which can be applied to fields such as secure communication, radar, optical time domain reflectometry and random number generation. Background Art

[0002] Chaotic lasers, due to their noise-like properties, large amplitude, and wide spectrum, have been widely used in fields such as secure communications, radar ranging, and random number generation. Chaotic lasers can be generated by applying external perturbations to semiconductor lasers. Typical perturbations include optical feedback, optical injection, and photoelectric feedback.

[0003] However, the chaotic laser generated by this method has two drawbacks: First, the generated chaotic laser is only a single-channel chaotic signal, which cannot meet the parallelization requirements of current applications. For example, lidar often requires multi-channel measurement to achieve three-dimensional imaging. Second, due to the influence of relaxation oscillations in the semiconductor laser itself, the chaotic laser generated by this method has an uneven spectrum and a limited spectral bandwidth (only a few GHz). This limits the performance of chaotic lasers in specific applications, such as the transmission speed of chaotic secure communications, the generation rate of physical random numbers, and the spatial resolution of chaotic lidar.

[0004] In response to the problem that multi-channel parallel chaotic lasers are difficult to achieve, researchers have proposed some solutions, such as using a continuous wave laser with phase modulation injection and an external cavity chaotic laser to generate two parallel chaotic signals [Opto-Electronic Advances, 2022, 5(5), 200026]; using an external cavity semiconductor laser with external self-phase modulation and three-way filtering to achieve three-way parallel chaotic signal generation [Journal of Lightwave Technology, 2022, 40(3), 751-761]; using Fabry-Perot lasers for optical feedback combined with multi-way filters to achieve multi-channel parallel chaotic signal generation [Optics Express, 2019, 27(13), 17859-17867]. However, the number of parallel chaotic output paths generated by the above methods is limited, which cannot meet the scalability requirements of multi-channel chaotic signals in practical applications.

[0005] To address the limited bandwidth of chaotic lasers, researchers have proposed various methods to enhance the bandwidth of chaotic lasers, such as cascading semiconductor lasers, self-phase modulation feedback, optical time lenses, and the use of special lasers. However, these solutions can only achieve single-channel broadband chaotic signal output.

[0006] In summary, achieving parallel and scalable broadband chaos generation is still a technical challenge, and the development of a multi-channel parallel broadband chaos laser generation device is urgent. Summary of the Invention

[0007] The purpose of the present invention is to provide a multi-channel broadband chaotic laser generating device based on a micro-ring resonator to solve the problems of the lack of existing multi-channel broadband chaotic laser implementation solutions or unsatisfactory output signals.

[0008] The present invention provides a multi-channel broadband chaotic laser generating device based on a micro-ring resonator, comprising a distributed feedback semiconductor laser, a polarization controller, an adjustable optical attenuator, a micro-ring resonator, an optical fiber reflector, and a wavelength division multiplexer. The distributed feedback semiconductor laser is connected to the polarization controller, the adjustable optical attenuator, and the input end on the left side of the upper straight waveguide of the micro-ring resonator in sequence; the straight-through end on the right side of the upper straight waveguide of the micro-ring resonator is connected to the optical fiber reflector; the left download end of the lower straight waveguide of the micro-ring resonator is connected to the wavelength division multiplexer; the distributed feedback semiconductor laser, the polarization controller, the adjustable optical attenuator, the upper straight waveguide of the micro-ring resonator, and the optical fiber reflector constitute a feedback loop; wherein, the continuous light output by the distributed feedback semiconductor laser is polarized by the polarization controller and then injected into the micro-ring resonator through the adjustable optical attenuator. The input end is output from the straight-through port and reflected by the fiber reflector. The reflected light is fed back into the distributed feedback semiconductor laser to implement perturbations, thereby making the distributed feedback semiconductor laser operate in an initial chaotic state. Then, the initial chaotic light is coupled into the ring waveguide from the input end of the micro-ring resonator, and the nonlinear effect and dispersion occur in the ring waveguide, which greatly broadens the spectrum. After being output from the download port of the micro-ring resonator, a chaotic optical frequency comb with n comb teeth with equal frequency spacing is generated. Finally, it is demultiplexed into n high-bandwidth chaotic signals through a wavelength division multiplexer.

[0009] In a multi-channel broadband chaotic laser generating device based on a microring resonator described in the present invention, the center wavelength of the laser output by the distributed feedback semiconductor laser is located at the blue detuning point of the resonance peak of the microring resonator, that is, the pump wavelength is smaller than the wavelength corresponding to the nearest resonant frequency.

[0010] In the multi-channel broadband chaotic laser generating device based on a micro-ring resonator of the present invention, the number of output channels of the wavelength division multiplexer is equal to the number of comb teeth of the chaotic optical frequency comb.

[0011] In the multi-channel broadband chaotic laser generating device based on a micro-ring resonator described in the present invention, the channel bandwidth of the wavelength division multiplexer should be larger than the linewidth of a single comb tooth of the chaotic optical frequency comb.

[0012] The advantages and positive effects of the multi-channel broadband chaotic laser generating device based on a micro-ring resonator provided by the present invention are as follows:

[0013] 1. This technical solution uses a microring resonator to generate a chaotic optical frequency comb, and then uses wavelength division multiplexing technology to achieve multi-channel parallel chaotic laser generation. It can greatly meet the needs of multi-channel secure communication, multi-channel physical random number generation, and multi-target radar detection.

[0014] 2. This technical solution uses optical methods to generate chaotic signals, which can effectively overcome the electronic bandwidth bottleneck. The spectrum bandwidth of each chaotic signal generated can reach tens of GHz.

[0015] 3. The number of chaotic laser paths generated by this technical solution can be further expanded. By increasing the optical power entering the microring resonator or using a microring resonator with a higher nonlinear coefficient, the number of comb teeth in the chaotic optical frequency comb can be further increased, thereby achieving the generation of more broadband chaotic signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural schematic diagram of a multi-channel broadband chaotic laser generating device based on a micro-ring resonator provided by the present invention.

[0017] Figure 2 This is a transmission characteristic curve diagram of the download end of the micro-ring resonator in a multi-channel broadband chaotic laser generating device based on a micro-ring resonator provided by the present invention.

[0018] Figure 3 This is a typical spectrum diagram of the chaotic optical frequency comb output from the download end of the micro-ring resonator in a multi-channel broadband chaotic laser generating device based on a micro-ring resonator provided by the present invention.

[0019] Figure 4 The figure shows the typical broadband chaotic spectrum obtained by filtering out a single comb tooth from the spectrum of the chaotic optical frequency comb. DETAILED DESCRIPTION

[0020] The technical measures of the present invention are described in detail below with reference to the accompanying drawings so that those skilled in the art can have a clearer understanding of the objectives, advantages, and technical measures of the present invention. Based on the implementation examples of the present invention, any other embodiments obtained by other technicians in this field without performing creative work may be classified as within the scope of protection of the present invention.

[0021] The present invention provides a multi-channel broadband chaotic laser generating device based on a micro-ring resonator, comprising a distributed feedback semiconductor laser 1, a polarization controller 2, an adjustable optical attenuator 3, a micro-ring resonator 4, an optical fiber reflector 5 and a wavelength division multiplexer 6; the distributed feedback semiconductor laser 1 is connected in sequence with the polarization controller 2, the adjustable optical attenuator 3 and the input end on the left side of the upper straight waveguide of the micro-ring resonator 4; the straight-through end on the right side of the upper straight waveguide of the micro-ring resonator 4 is connected to the optical fiber reflector 5; the left download end of the lower straight waveguide of the micro-ring resonator 4 is connected to the wavelength division multiplexer 6; the distributed feedback semiconductor laser 1, the polarization controller 2, the adjustable optical attenuator 3, the upper straight waveguide of the micro-ring resonator 4 and the optical fiber reflector 5 constitute a feedback loop; wherein, the distributed feedback The continuous light output by the distributed feedback semiconductor laser 1 is polarized by the polarization controller 2, and then injected into the input end of the micro-ring resonator 4 through the variable optical attenuator 3. It is output from the through port and reflected by the fiber reflector 5. The reflected light is fed back into the distributed feedback semiconductor laser 1 to implement perturbations, thereby making the distributed feedback semiconductor laser 1 operate in an initial chaotic state. Furthermore, the initial chaotic light is coupled into the ring waveguide from the input end of the micro-ring resonator 4, and the nonlinear effect and dispersion occur in the ring waveguide, resulting in a significant spectrum broadening. After being output from the download port of the micro-ring resonator 4, a chaotic optical frequency comb with n comb teeth with equal frequency spacing is generated. Finally, it is demultiplexed into n high-bandwidth chaotic signals through the wavelength division multiplexer 6.

[0022] When implementing it specifically, Figure 1 The distributed feedback semiconductor laser 1 shown outputs a continuous laser with a central wavelength of 1064 nm and a power of 1 W, which is injected into the micro-ring resonator 4 after passing through the polarization controller 2 and the adjustable optical attenuator 3. In the embodiment, the resonance line width of the micro-ring resonator 4 is 0.2 nm (e.g. Figure 2 ), the nonlinear coefficient is 200W -1 km -1The resonant wavelength closest to the pump light is 1064.05 nm. Light enters the input of the microring resonator 4. The output of the through-port forms optical feedback with the fiber reflector 5. The feedback light returns to the distributed feedback semiconductor laser 1, perturbing it and causing it to operate in a chaotic oscillation state. After the initial chaotic light sequence is coupled from the input into the ring waveguide of the microring resonator 4, it is first split into multiple ultrashort pulses due to four-wave mixing. Within the ring waveguide, the ultrashort pulses are further split into a series of optical solitons with varying peak powers and pulse widths due to the combined effects of self-phase modulation, Raman scattering, and high-order dispersion. Simultaneously, the solitons' self-frequency shifts and soliton collisions broaden the spectrum at long wavelengths. Furthermore, the solitons transfer some of their energy to short wavelengths, forming dispersive waves, which further broaden the spectrum at short wavelengths. Cross-phase modulation occurs between the solitons and the dispersive waves, further broadening the spectrum at short wavelengths. In summary, the combined effects of nonlinear effects and dispersion generate many new frequency components, significantly broadening the original chaotic spectrum. After being output from the download end of the micro-ring resonator 4, the spectrum of the chaotic laser signal will appear as a series of optical frequency combs with equal frequency spacing. Figure 3 This is the spectrum of the resulting chaotic optical frequency comb. Each peak in the figure represents a tooth of the chaotic optical frequency comb, and the linewidth of each tooth is equal to the resonance linewidth of the microring resonator 4, which is 0.2nm. In the figure, mode 0 represents the comb tooth corresponding to the pump light wavelength. There are m teeth symmetrically distributed on both sides of it, and the value of m can reach more than 100. Then, using a wavelength division multiplexer 6 with a channel bandwidth of 0.2nm and a number of channels of n (n=2m+1), each tooth of the generated chaotic optical frequency comb can be demultiplexed into n broadband chaotic laser signals. After testing, the -3dB bandwidth of each chaotic laser spectrum can reach 35GHz, as shown in Figure 1. Figure 4 shown.

[0023] It is particularly important to note that the chaotic optical frequency comb generated by the microring resonator 4 in the present invention can be demultiplexed into hundreds of broadband chaotic laser signals, and the number of broadband chaotic laser signals can be further expanded by increasing the pump light power or using a microring resonator 4 with a higher nonlinear coefficient. These advantages make the present invention effective in meeting the high-speed parallelization requirements of current applications, such as multi-channel high-speed secure communications, parallel radar detection, and multi-channel high-speed random number generation.

[0024] The above description is only a detailed description of the technical measures of the present invention to facilitate understanding by those skilled in the art, but it does not limit the scope of protection of the present invention. For those skilled in the art, direct or indirect application in other related scientific and technological aspects in various equivalent forms or equivalent methods also falls within the scope of patent protection of the present invention.

Claims

1. A multi-path broadband chaotic laser generating device based on a microring resonator, comprising a distributed feedback semiconductor laser, a polarization controller, an adjustable optical attenuator, a microring resonator, an optical fiber reflector, and a wavelength division multiplexer; the distributed feedback semiconductor laser, the polarization controller, the adjustable optical attenuator, and the input end on the left side of the upper straight waveguide of the microring resonator are sequentially connected; the through end on the right side of the upper straight waveguide of the microring resonator is connected to the optical fiber reflector; the left side download end of the lower straight waveguide of the microring resonator is connected to the wavelength division multiplexer; the distributed feedback semiconductor laser, the polarization controller, the adjustable optical attenuator, the upper straight waveguide of the microring resonator, and the optical fiber reflector constitute a feedback loop; wherein, The continuous light output by the distributed feedback semiconductor laser is polarized by the polarization controller and then injected into the input end of the micro-ring resonator through the adjustable optical attenuator. It is output from the through port and reflected by the fiber reflector. The reflected light is fed back into the distributed feedback semiconductor laser to perform perturbations, thereby making the distributed feedback semiconductor laser work in the initial chaotic state. Then, the initial chaotic light is coupled into the ring waveguide from the input end of the micro-ring resonator, and the nonlinear effect and dispersion occur in the ring waveguide. The spectrum is greatly broadened. After being output from the download port of the micro-ring resonator, it will produce a chaotic state. n A chaotic optical frequency comb with equal frequency spacing; finally demultiplexed by a wavelength division multiplexer n High bandwidth chaotic signal.

2. The multi-channel broadband chaotic laser generating device based on a micro-ring resonator according to claim 1, characterized in that: The central wavelength of the laser output by the distributed feedback semiconductor laser is located at the blue detuning point of the resonance peak of the microring resonator, that is, the pump wavelength is smaller than the wavelength corresponding to the nearest resonance frequency.

3. The multi-channel broadband chaotic laser generating device based on a micro-ring resonator according to claim 1, characterized in that: The number of output channels of the wavelength division multiplexer is equal to the number of teeth of the chaotic optical frequency comb.

4. The multi-channel broadband chaotic laser generating device based on a micro-ring resonator according to claim 1, characterized in that: The channel bandwidth of the wavelength division multiplexer is larger than the linewidth of a single comb tooth of the chaotic optical frequency comb.

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