External light injection spin-vcsel periodic oscillation millimeter wave signal generation device and method

Abstract

This invention relates to an externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device and method. The device and method of this invention inject light emitted from a master laser into a slave laser, such that the frequency of the generated millimeter-wave signal is the sum of the frequency detuning of the master and slave lasers and their birefringence. Compared with light-injected conventional VCSELs, this invention has a wider frequency range; compared with spin laser systems, this invention has continuously adjustable characteristics. Simultaneously, this invention employs a design with added feedback loops to achieve linewidth compression and further phase stabilization of the millimeter-wave signal.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a device and method for generating millimeter-wave signals by externally injected spin VCSEL periodic oscillation. Background Technology

[0002] Millimeter waves possess characteristics such as high frequency band, wide spectrum, and good transmission bandwidth and speed. Therefore, the application of millimeter wave transmission can meet the increasing demand for wireless communication capacity and solve the problem of limited bandwidth in the current microwave frequency band. Whether in optical radio frequency transmission systems (ROF) or military radar representing the forefront of scientific research, high-quality microwave and millimeter wave signal sources play a crucial role. Optically generated microwave technology utilizes photonic methods to generate microwave signals. Due to its advantages such as high frequency, ability to transmit in optical fibers, immunity to electromagnetic interference, and ease of wavelength division multiplexing, it has received widespread attention and extensive research in recent years. Common optically generated microwave technology schemes mainly include external modulation methods, optical heterodyne methods, direct modulation methods, photoelectric oscillator technology, and single-cycle oscillation technology. These optically generated microwave technology schemes have their own advantages. Among them, microwave signals generated based on single-cycle oscillation dynamics have advantages such as high frequency, single-sideband spectral structure characteristics, and a large frequency tunable range. For example: a scheme that uses continuous wave light injected into a semiconductor laser to generate a single-period oscillation and uses mirror feedback to stabilize the microwave signal (see [JPZhuang and SCChan, "Phase noise characteristics of microwave signals generated by semiconductor laser dynamics," Opt. Express 23, 2777-2797 (2015)]); a scheme that generates tunable microwave signals based on the single-period oscillation of an optically injected vertical-cavity surface-emitting laser (see [S.J. Ji, Y. Hong, PS Spencer, J. Benedikt, and I. Davies, "Broad tunable photonic microwave generation based on period-one dynamics of optical injection vertical-cavity surface-emitting lasers," Opt. Express 25 (17), 19863-19871 (2017)]); and a scheme that generates microwave signals based on the single-period oscillation of a free-running spin vertical-cavity surface-emitting laser (see [Y. Huang, P. Zhou, and N. Li, "Broad tunable photonic microwave generation in an optically pumped vertical-cavity surface-emitting laser"). spin-VCSEL with optical feedback stabilization,"Opt. Lett.46(13),3147-3151(2021)]).

[0003] While current millimeter-wave generation schemes based on single-spin VCSELs offer advantages such as simple structure and a wide frequency tuning range, they rely on external stress to adjust the birefringence. However, in practical applications, adjusting the birefringence is challenging and difficult to achieve continuously adjustable values, thus failing to meet the needs of many applications. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an apparatus and method for generating millimeter-wave signals by externally injected spin VCSEL periodic oscillation.

[0005] An externally light-injected spin VCSEL periodic oscillation millimeter-wave signal generation device includes:

[0006] A signal generation module, comprising a master laser and a slave laser, wherein the beam emitted by the master laser is injected into the slave laser to generate a single-cycle oscillation signal;

[0007] A first optical polarization controller is used to control the polarization state of the single-cycle oscillation signal to generate a polarized beam.

[0008] The feedback module divides the polarized beam into a first branch beam and a second branch beam, and the first branch beam is fed back to the slave laser.

[0009] Photoelectric conversion module, which receives the second branch beam and generates millimeter wave signal by beat frequency;

[0010] The slave laser is a spin VCSEL, and the frequency of the millimeter-wave signal is the sum of the detuning frequencies of the master laser and the slave laser and their birefringence.

[0011] Preferably, the optically pumped spin VCSEL is injected with spin carriers from a laser.

[0012] Preferably, the pump source of the optically pumped spin VCSEL with spin carrier injection is a 980nm continuous wave output.

[0013] Preferably, the light emitted by the main laser is linearly polarized, circularly polarized, or elliptically polarized.

[0014] Preferably, the feedback module includes: an optical coupler, a first feedback loop, a second feedback loop, and an optical circulator. Both the first and second feedback loops include a delay fiber, a variable attenuator, and a second optical polarization controller connected in sequence. The optical coupler splits the polarized beam into a first branch beam and a second branch beam. The first branch beam is further divided into an upper branch beam and a lower branch beam. The upper branch beam and the lower branch beam pass through the first and second feedback loops, respectively, and are then injected into the slave laser via the optical circulator.

[0015] Preferably, the lengths of the delay fibers included in the first feedback loop and the second feedback loop are different.

[0016] Preferably, the photoelectric conversion module includes:

[0017] An optical isolator, wherein the optical isolator is used to receive the second branch beam and maintain unidirectional transmission;

[0018] The photodetector receives the second branch light output from the optical isolator and performs beat frequency generation to produce a millimeter-wave signal.

[0019] A method for generating periodic oscillation millimeter-wave signals using an externally injected spin VCSEL is disclosed. This method is implemented using the externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device described above, and includes:

[0020] S1: The master laser emits light and injects it into the slave laser, which then emits a single-cycle oscillation signal;

[0021] S2: Controls the polarization state of the single-cycle oscillation signal to generate a polarized beam;

[0022] S3: Split the polarized beam into two optical paths, one of which is fed back to the laser.

[0023] S4: Another beam beat frequency generates a millimeter-wave signal.

[0024] Preferably, in step S1, the injection intensity and center frequency of the main laser are changed to increase the frequency range of the millimeter-wave signal.

[0025] Preferably, in step S2, one of the beams is fed back to the laser to increase the time delay, perform variable attenuation, and control the polarization state.

[0026] The technical solution of the present invention has the following advantages compared with the prior art:

[0027] The externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device and method of this invention generates a millimeter-wave signal by injecting light emitted from a master laser into a slave laser, causing frequency detuning. This results in the frequency of the generated millimeter-wave signal being the sum of the frequency detuning and the birefringence. Compared to conventional optically injected VCSELs, this invention achieves a higher frequency; compared to spin laser systems, it offers continuously adjustable characteristics. Furthermore, this invention employs a design with added feedback loops to further compress the linewidth and stabilize the phase of the millimeter-wave signal. Attached Figure Description

[0028] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the external light-injected spin VCSEL periodic oscillation millimeter-wave signal generation device of the present invention.

[0030] Figure 2 This is a timing diagram for the present invention.

[0031] Figure 3 This is the spectral diagram of the present invention.

[0032] Figure 4 This is a spectrum diagram of the present invention.

[0033] Explanation of reference numerals in the accompanying drawings: 1. Slave laser; 2. Master laser; 3. First optical polarization controller; 4. Optical circulator; 5. Second optical polarization controller; 6. Variable attenuator; 7. Delay fiber; 8. Optical coupler; 9. Optical isolator; 10. Photodetector. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0035] like Figure 1 As shown, the present invention provides an externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device, comprising:

[0036] A signal generation module, comprising a main laser 2 and a slave laser 1, wherein the beam emitted by the main laser 2 is injected into the slave laser 1 to generate a single-cycle oscillation signal;

[0037] The first optical polarization controller 3 is used to control the polarization state of the single-cycle oscillation signal to generate a polarized beam.

[0038] The feedback module divides the polarized beam into a first branch beam and a second branch beam, and the first branch beam is fed back to the slave laser 1.

[0039] Photoelectric conversion module, which receives the second branch beam and generates millimeter wave signal by beat frequency;

[0040] Wherein, the slave laser 1 is a spin VCSEL, and the frequency of the millimeter-wave signal is the sum of the detuning frequency of the master laser 2 and the slave laser 1 and the birefringence.

[0041] In an optional embodiment, the optically pumped spin VCSEL is injected with spin carriers from laser 1. Preferably, the pump source of the optically pumped spin VCSEL is a 980nm continuous wave output.

[0042] In one specific embodiment, the light emitted by the main laser 2 is linearly polarized, circularly polarized, or elliptically polarized.

[0043] In one specific embodiment, the feedback module includes an optical coupler 8, a first feedback loop, a second feedback loop, and an optical circulator 4. Both the first and second feedback loops include a delay fiber 7, a variable attenuator 6, and a second optical polarization controller 5 connected sequentially. The optical coupler 8 splits the polarized beam into a first branch beam and a second branch beam. The first branch beam is further divided into an upper branch beam and a lower branch beam. The upper and lower branch beams pass through the first and second feedback loops, respectively, and are then injected into the slave laser 1 via the optical circulator 4. In one embodiment of the invention, the lengths of the delay fibers 7 included in the first and second feedback loops are unequal. For example, the length of the delay fiber 7 included in the first feedback loop is shorter than the length of the delay fiber 7 included in the second feedback loop. In an optional embodiment, the feedback loop is an all-optical feedback or an electro-optical feedback, and its transmission form is optical fiber transmission or spatial optical transmission. This embodiment uses a feedback loop to store phase information. After the feedback is applied, the single-cycle oscillation mode is locked to the external cavity mode of the feedback loop, which reduces the phase noise caused by the laser signal and further compresses the linewidth, thereby obtaining a dual-path, high-frequency, wide-bandwidth and flexibly tunable millimeter-wave signal.

[0044] In one specific embodiment, the photoelectric conversion module includes:

[0045] Optical isolator 9, which is used to receive the second branch beam and maintain unidirectional transmission;

[0046] The photodetector 10 receives the second branch light output by the optical isolator 9 and performs beat frequency to generate a millimeter-wave signal.

[0047] The single-cycle oscillation waveform generated by the optically pumped spin VCSEL injected by laser A was simulated through numerical simulation, and the rate equation is established as follows:

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] Among them, E x and E y This represents the amplitude of the linearly polarized field. and Indicates phase, n + and n - Represents the normalized carrier density, and can be used to represent the normalized carrier variables N and m, respectively. γ s γ represents the spin relaxation rate of coupled spin-up and spin-down carriers. p For birefringence, γ a The linear dichroism is represented by κ, the optical field decay rate is γ, the carrier recombination rate is α, the linewidth enhancement factor is α, and the total normalized pump rate is η, defined as η = η + +η - ,β sp ξ represents the spontaneous emission factor. x,y For Gaussian white noise, τ 1，2 k represents the feedback delay of the first and second feedback loops. f1,2 Let f0 be the feedback intensity of the first and second feedback loops, and f0 be the laser operating frequency. The ellipticity P is defined as... E injx and E injy δ represents the field amplitude of the injected signal. x and δ y This corresponds to the phase, and the relationship between the two fields can be determined by the jet angle θ. p To indicate, E injx =E injy tanθ p P inj For injection level, defined as in Δω is the detuning frequency, defined as the light injection angular frequency ω. inj The polarization X component (ω) of the spin VCSEL x =αα a -γ p ) and y component (ω y =γ p -αγ a The difference in mid-frequency between ).

[0055] The parameters in the simulation are set as follows: κ = 250 ns -1 α = 3, γ = 1 ns -1 γ s =63ns -1 γ a =0, γ p =ns -1 η = 2, β sp =10 -5 K inj =150ns -1 θ p =45°, δ=90°, Δω=-55GHz. Figure 2 The waveform of a single-cycle oscillation signal generated by injecting right-hand circularly polarized light into an optically pumped spin VCSEL. Figure 3 This is the spectrum of the output single-cycle oscillation signal under right-hand circularly polarized light injection. The figure shows that the difference between the operating frequency of the master laser 2 and the master frequency of the slave laser 1 is -25 GHz, and the birefringence is 30πns. -1 A frequency of 55 GHz (Δω+γ) can be generated through beat frequency. p Microwave signals of / π). Figure 4 Based on the microwave spectrum generated by the method and apparatus of this invention, from Figure 4 In (a), the millimeter-wave linewidth is about 3.7 MHz without external light injection, but after external light injection, the linewidth of the millimeter-wave is compressed to 10 kHz. Thus, a high-frequency, narrow-linewidth, high-quality photonic microwave signal was obtained through external light injection.

[0056] This invention also provides a method for generating a periodic oscillation millimeter-wave signal from an externally injected spin VCSEL. This method is implemented using the externally injected spin VCSEL periodic oscillation millimeter-wave signal generating device described above, and can be referred to in correspondence with the externally injected spin VCSEL periodic oscillation millimeter-wave signal generating device described above. The method includes:

[0057] S1: The main laser 2 emits light injected into the slave laser 1, and the main laser 2 emits a single-cycle oscillation signal;

[0058] S2: Controls the polarization state of the single-cycle oscillation signal to generate a polarized beam;

[0059] S3: Split the polarized beam into two optical paths, one of which is fed back to laser 1;

[0060] S4: Another beam beat frequency generates a millimeter-wave signal.

[0061] In one specific embodiment, step S1 involves changing the injection intensity and center frequency of the main laser 2 to increase the frequency range of the millimeter-wave signal.

[0062] In one specific embodiment, in step S2, one of the beams is fed back to the laser to increase the time delay, perform variable attenuation, and control the polarization state.

[0063] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An external optical injection spin-VCSEL periodic oscillation millimeter wave signal generation device, characterized by, include: The signal generation module includes a master laser and a slave laser. The beam emitted by the master laser is injected into the slave laser to generate a single-cycle oscillation signal. The light emitted by the master laser is circularly polarized or elliptically polarized. A first optical polarization controller is used to control the polarization state of the single-cycle oscillation signal to generate a polarized beam. The feedback module splits the polarized beam into a first branch beam and a second branch beam, and the first branch beam is fed back to the slave laser; the feedback module includes a first feedback loop and a second feedback loop; both the first feedback loop and the second feedback loop include a delay fiber, a variable attenuator, and a second optical polarization controller connected in sequence, and the lengths of the delay fibers included in the first feedback loop and the second feedback loop are different; Photoelectric conversion module, which receives the second branch beam and generates millimeter wave signal by beat frequency; Wherein, the slave laser is a spin VCSEL, the frequency of the millimeter-wave signal is the sum of the detuning frequency of the master laser and the slave laser and the birefringence, and the detuning frequency is negative detuning.

2. The external optical injection spin-VCSEL periodic oscillation millimeter wave signal generating device according to claim 1, wherein The optically pumped spin VCSEL is injected with spin carriers from a laser.

3. The external optical injection spin-VCSEL periodic oscillation millimeter wave signal generating device according to claim 2, wherein The pump source for the optically pumped spin VCSEL with spin carrier injection is a 980nm continuous wave output.

4. The externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device according to claim 1, characterized in that, The feedback module further includes an optical coupler and an optical circulator; the optical coupler divides the polarized beam into a first branch beam and a second branch beam; wherein, the first branch beam is divided into an upper branch beam and a lower branch beam, and the upper branch beam and the lower branch beam are injected into the slave laser after passing through the first feedback loop and the second feedback loop, respectively, via the optical circulator.

5. The externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device according to claim 4, characterized in that, The photoelectric conversion module includes: An optical isolator, wherein the optical isolator is used to receive the second branch beam and maintain unidirectional transmission; The photodetector receives the second branch light output from the optical isolator and performs beat frequency generation to produce a millimeter-wave signal.

6. A method for generating periodic oscillating millimeter-wave signals from an externally injected spin VCSEL, characterized in that, This method is implemented using the externally injected spin VCSEL periodic oscillation millimeter-wave signal generation device as described in claims 1-5, and the method includes: S1: The master laser emits light and injects it into the slave laser, which then emits a single-cycle oscillation signal; S2: Controls the polarization state of the single-cycle oscillation signal to generate a polarized beam; S3: Split the polarized beam into two optical paths, one of which is fed back to the laser. S4: Another beam beat frequency generates a millimeter-wave signal.

7. The method for generating periodic oscillation millimeter-wave signals from an externally injected spin VCSEL according to claim 6, characterized in that, In step S1, the injection intensity and center frequency of the main laser are changed to increase the frequency range of the millimeter-wave signal.

8. The method for generating periodic oscillation millimeter-wave signals using an externally injected spin VCSEL according to claim 6, characterized in that, In step S2, one of the beams is fed back to the laser to increase the time delay, perform variable attenuation, and control the polarization state.

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