Integrated chaotic signal generator based on y-type waveguide and single micro-ring structure

Abstract

This invention relates to the field of photonic integrated chaotic semiconductors, and discloses an integrated chaotic signal generator based on a Y-shaped waveguide and a single micro-ring structure. The generator includes a first DFB chip, a second DFB chip, a Y-shaped waveguide, a micro-ring waveguide, a first transmission waveguide, a second transmission waveguide, and a feedback end face. One end face of the first DFB chip is connected to one end of the first transmission waveguide, and the other end of the first transmission waveguide is connected to a first branch of the Y-shaped waveguide. The feedback end face is connected to one end of the second transmission waveguide, and the other end of the second transmission waveguide is connected to a second branch of the Y-shaped waveguide. The bus waveguide of the Y-shaped waveguide is connected to one end face of the second DFB chip. The micro-ring waveguide is disposed between the first and second transmission waveguides, with both sides of the micro-ring waveguide coupled to the first and second transmission waveguides, respectively. This invention features a simple structure, small size, low cost, and ease of integration, and can be widely applied in fields such as chaotic secure optical communication and lidar.

Description

Technical Field

[0001] This invention relates to the field of photonic integrated chaotic semiconductor lasers, specifically an integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure. Background Technology

[0002] Chaotic lasers possess characteristics such as high bandwidth, wide spectrum, and low latency, and are widely used in fields such as lidar, chaotic secure optical communication, and high-speed random number generation. In practice, however, semiconductor lasers are typically used to generate chaotic lasers due to their advantages of small size and light weight.

[0003] Currently, there are three typical methods for generating chaotic lasers: external cavity optical feedback, external light injection, and photoelectric feedback. External cavity optical feedback is the most commonly used method because it is relatively simple and easy to control. Its principle is that the output light of the laser is incident on a reflector, and a portion of the light is fed back, perturbing the laser and generating chaotic laser light. External light injection works by using two lasers; the output light of one laser enters the second laser, perturbing it, and ultimately causing the second laser to output chaotic laser light. Photoelectric feedback works by converting the optical signal into an electrical signal, which then returns to the laser through a specific path, perturbing it and ultimately generating chaotic laser light. However, optical feedback structures, due to their fixed feedback cavity length, exhibit a certain time delay in their output, affecting the generation of random numbers. Furthermore, they are limited by the relaxation oscillation frequency of semiconductor lasers, and since most chaotic lasers exhibit significant relaxation oscillation characteristics, this also affects the bandwidth of the chaotic laser.

[0004] To address these issues, scientists have proposed various methods to enhance the bandwidth and suppress the time delay characteristics of chaotic lasers. Professor Wang Anbang and colleagues at Taiyuan University of Technology studied the dynamic path for bandwidth enhancement of chaotic semiconductor lasers using optical feedback and continuous optical injection. The standard bandwidth of the chaotic laser generated through optical feedback increased from 6.2 GHz to 16.8 GHz [Optics Express, 2013, 21(12): 14017-14035]. Wu Jiagui and colleagues at Southwest University used a mutual injection structure to experimentally generate two sets of time-delay-suppressed chaotic lasers [IEEE Photonics Technol. Lett. 2011;23(12):759-761]. Professors Zhang Mingjiang and Wang Anbang at Taiyuan University of Technology proposed injecting a chaotic laser into an optical fiber ring resonator to obtain a broadband chaotic laser with a bandwidth greater than 26.5 GHz and a flatness of ±1.5 dB. Furthermore, adding optical filters and optical amplifiers to the optical resonant cavity can improve the bandwidth of chaotic lasers [Journal of Lightwave Technology, 2007, 25(1): 381-386]. All of these structures can enhance bandwidth and suppress latency to some extent, but they are all built from discrete components and are not conducive to integration. Summary of the Invention

[0005] This invention overcomes the shortcomings of existing technologies and aims to solve the following technical problem: providing a novel chaotic signal generator to generate chaotic lasers with large bandwidth and low latency, thereby solving the problems of large size, susceptibility to interference, uneven power, and obvious latency characteristics of current chaotic signal generators.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: an integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure, comprising a first DFB chip, a second DFB chip, a Y-type waveguide, a micro-ring waveguide, a first transmission waveguide, a second transmission waveguide, and a feedback end face;

[0007] One end face of the first DFB chip is connected to one end of the first transmission waveguide, and the other end of the first transmission waveguide is connected to the first branch of the Y-type waveguide; one end of the second transmission waveguide is provided with a feedback end face, and the other end is connected to the second branch of the Y-type waveguide, and the bus waveguide of the Y-type waveguide is connected to one end face of the second DFB chip.

[0008] The micro-ring waveguide is disposed between the first transmission waveguide and the second transmission waveguide. One side of the micro-ring waveguide is coupled to the first transmission waveguide in coupling region a, and the other side of the micro-ring waveguide is coupled to the second transmission waveguide in coupling region b.

[0009] Preferably, the integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure further includes a silicon substrate, wherein the first DFB chip, the second DFB chip, the Y-type waveguide, the micro-ring waveguide, the first transmission waveguide, the second transmission waveguide, and the feedback end face are all disposed on the silicon substrate.

[0010] Preferably, the free emission wavelength of the first DFB chip and the second DFB chip is 1550nm, and the light-emitting end faces at both ends are natural dissociation surfaces.

[0011] Preferably, the splitting ratio of the two branches of the Y-shaped waveguide is 1:1, and the included angle is 4°.

[0012] Preferably, the reflectivity of the feedback end face is 0.2.

[0013] Preferably, the first transmission waveguide, the second transmission waveguide, and the bus waveguide are parallel to each other.

[0014] Preferably, in coupling region a, the distance between the first transmission waveguide and the micro-ring waveguide is less than 0.1 μm, and in coupling region b, the distance between the second transmission waveguide and the micro-ring waveguide is less than 0.1 μm.

[0015] Preferably, the micro-ring waveguide is circular with a radius of 0.5~0.7μm.

[0016] Preferably, the coupling efficiency between the first transmission waveguide and the micro-ring waveguide is 60%, and the coupling efficiency between the second transmission waveguide and the micro-ring waveguide is 60%.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. This invention provides an integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure. It uses a Y-type waveguide and a micro-ring waveguide, and utilizes the principles of optical feedback and mutual injection to allow multiple optical signals to disturb the first DFB chip 1 and the second DFB chip 6 respectively. Chaotic laser is generated at another output port of the first DFB chip 1 and the second DFB chip 6. Since the micro-ring waveguide has a dynamic phase, a chaotic laser with a large bandwidth and low time delay can be obtained in the end.

[0019] 2. This invention only includes micro-ring waveguides and Y-type waveguides, and has low loss;

[0020] 3. The device of the present invention can be integrated on silicon, and has the advantages of small structure and low cost.

[0021] In summary, the integrated chaotic signal generator based on a Y-shaped waveguide and a single micro-ring structure proposed in this invention has a reasonable structural design and can be used to generate chaotic lasers with large bandwidth and low time delay. By leveraging the low loss of the micro-ring waveguide and the Y-shaped waveguide, and by using multiple optical perturbations on the first DFB chip 1 laser and the second DFB chip 6 laser, the invention effectively overcomes the shortcomings of traditional methods in generating chaotic lasers, such as narrow bandwidth and significant time delay characteristics, and has promising prospects for practical applications. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an integrated chaotic signal generator based on a Y-shaped waveguide and a single micro-ring structure, provided as an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the coupling point during optical transmission.

[0024] In the figure: 1 is the first DFB chip, 2 is the first transmission waveguide, 3 is the micro-ring waveguide, 4 is the Y-type waveguide, 5 is the bus waveguide, 6 is the second DFB chip, 7 is the second transmission waveguide, 8 is the feedback end face, and 9 is the silicon substrate. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figures 1-2 As shown, this embodiment of the invention provides an integrated chaotic signal generator based on a Y-shaped waveguide and a single micro-ring structure, including a first DFB chip 1, a second DFB chip 6, a Y-shaped waveguide 4, a micro-ring waveguide 3, a first transmission waveguide 2, a second transmission waveguide 7, and a feedback end face 8; wherein, one end of the first branch, the second branch, and the bus waveguide 5 are connected together to form a Y-shaped Y-shaped waveguide 4.

[0027] One end face of the first DFB chip 1 is connected to one end of the first transmission waveguide 2, and the other end of the first transmission waveguide 2 is connected to the first branch of the Y-type waveguide; the feedback end face 8 is connected to one end of the second transmission waveguide 7, and the other end of the second transmission waveguide 7 is connected to the second branch of the Y-type waveguide; the bus waveguide 5 of the Y-type waveguide 4 is connected to one end face of the second DFB chip 6.

[0028] The micro-ring waveguide 3 is disposed between the first transmission waveguide 2 and the second transmission waveguide 7. One side of the micro-ring waveguide 3 is coupled to the first transmission waveguide 2 in coupling region a, and the other side of the micro-ring waveguide 3 is coupled to the second transmission waveguide 7 in coupling region b.

[0029] Furthermore, the integrated chaotic signal generator based on a Y-shaped waveguide and a single micro-ring structure in this embodiment also includes a silicon substrate 9, wherein the first DFB chip 1, the second DFB chip 6, the Y-shaped waveguide 4, the micro-ring waveguide 3, the first transmission waveguide 2, the second transmission waveguide 7 and the feedback end face 8 are all disposed on the silicon substrate 9.

[0030] Furthermore, in this embodiment, the free emission wavelength of the first DFB chip 1 and the second DFB chip 6 is 1550nm, and the light-emitting end faces of both the first DFB chip 1 and the second DFB chip 6 are natural dissociation surfaces. The ends of both DFB chips not connected to the waveguide can output chaotic laser signals.

[0031] Furthermore, in this embodiment, the splitting ratio of the two branches of the Y-shaped waveguide 4 is 1:1, and the included angle is 2~10°. More preferably, the included angle is 4°. At an included angle of 4°, the light has the best transmission efficiency when it is transmitted in the Y-shaped waveguide 4.

[0032] Specifically, in this embodiment, the feedback rate of the first DFB chip 1 and the second DFB chip 6 ranges from 0.08 to 0.2, which can perturb the corresponding laser to generate chaotic laser. Therefore, chaotic laser output can be achieved by adjusting the reflectivity of the feedback end face 8. The feedback rate refers to the ratio of the optical power fed back to the DFB chip through the feedback end face to the optical power freely emitted by the DFB chip. Specifically, in this embodiment, the feedback end face 8 can be an anti-reflection film with a reflectivity of 0.1 to 0.3.

[0033] Furthermore, in this embodiment, the reflectivity of the feedback end face 8 is 0.2.

[0034] Furthermore, the first transmission waveguide 2, the second transmission waveguide 7, and the bus waveguide 5 are parallel to each other. This parallelism facilitates laser coupling between the waveguides, thus improving coupling efficiency.

[0035] Specifically, in this embodiment, in coupling region a, the distance between the first transmission waveguide 2 and the micro-ring waveguide 3 is less than 0.1 μm, and in coupling region b, the distance between the second transmission waveguide 7 and the micro-ring waveguide 3 is less than 0.1 μm. Within this distance range, the optical coupling efficiency between the two transmission waveguides and the micro-ring waveguide 3 can meet the feedback requirements.

[0036] Furthermore, in this embodiment, the coupling efficiency between the first transmission waveguide 2 and the micro-ring waveguide 3 is 50-70%, and the coupling efficiency between the second transmission waveguide 7 and the micro-ring waveguide 3 is also 50-70%. Coupling efficiency refers to the percentage of light energy that can be coupled from a straight waveguide into the micro-ring. Theoretically, if the light intensity is high enough, even a lower coupling efficiency can transmit strong light, which can then be fed back to the DFB chip to generate disturbances, causing it to output chaotic laser light. The factors affecting coupling efficiency mainly depend on the spacing between the micro-ring waveguide 3 and the straight transmission waveguides (first transmission waveguide 2 and second transmission waveguide 7); the smaller the spacing, the higher the coupling efficiency.

[0037] Furthermore, in this embodiment, the coupling efficiency between the first transmission waveguide 2 and the micro-ring waveguide 3 is 60%, and the coupling efficiency between the second transmission waveguide 7 and the micro-ring waveguide 3 is 60%. Setting the coupling efficiency to 60% can take into account the light intensity of multiple feedback paths, so that the light intensity entering the micro-ring waveguide 3 and the straight end is appropriate. Then, the feedback intensity after the light is transmitted through multiple paths can all disturb the laser.

[0038] Specifically, in this embodiment, the micro-ring waveguide 3 is circular with a radius of 0.5~0.7μm.

[0039] Specifically, in this embodiment, the main disturbances experienced by the first DFB chip 1 are:

[0040] (1) The second DFB chip 6 directly injects disturbance into the first DFB chip 1 through the Y-type waveguide;

[0041] (2) The light generated by the first DFB chip 1 enters the micro-ring waveguide through the coupling region a, and is output at the coupling region b. The light output by the feedback end face 8 enters the micro-ring waveguide 3 from the coupling region b, and is output from the coupling region a, and is injected into the first DFB chip 1 to generate a disturbance.

[0042] (3) The light output from the second DFB chip 6 passes through the reflector at the lower port of the Y waveguide, and the light fed back from the feedback end face 8 enters the micro-ring waveguide 3 from the coupling area b position, and then outputs from the coupling area a position, injecting into the first DFB chip 1 to generate a disturbance.

[0043] Specifically, the main disturbances experienced by the second DFB chip 6 are:

[0044] (1) The first DFB chip 1 directly injects disturbance into the second DFB chip 6 through the first transmission waveguide 2 and the Y-type waveguide 4;

[0045] (2) The light output from the second DFB chip 6 enters the micro-ring waveguide 3 through the coupling region a, and is output at the coupling region b, and is injected into the second DFB chip 6 to generate a disturbance;

[0046] (3) The light output from the second DFB chip 6 enters the micro-ring waveguide 3 through the coupling region b, and is output at the coupling region a, and is injected into the second DFB chip 6 to generate a disturbance;

[0047] (4) The light output from the second DFB chip 6 passes through the feedback end face 8 of the lower port of the Y waveguide, and the feedback light causes a disturbance to the second DFB chip 6.

[0048] (5) The light generated by the first DFB chip 1 enters the micro-ring waveguide through the coupling region a and is output at the coupling region b. The light fed back through the feedback end face 8 is injected into the second DFB chip 6 along the lower branch of the Y-shaped waveguide to generate disturbance.

[0049] Therefore, in this embodiment of the invention, the principle of optical feedback and mutual injection is used to make multiple optical waves disturb the first DFB chip 1 and the second DFB chip 6 respectively, and generate chaotic laser at another output port of the first DFB chip 1 and the second DFB chip 6. Since the micro-ring waveguide has dynamic phase, a chaotic laser with large bandwidth and low time delay can be obtained in the end.

[0050] In summary, this invention proposes a chaotic signal generator composed of two DFB chips, a Y-shaped waveguide, and a micro-ring waveguide. Utilizing the coupling effect of the micro-ring waveguide and the branching effect of the Y-waveguide, the light generated by the two laser chips perturbs the two DFB chips multiple times, ultimately generating a high-performance chaotic laser. This structure has a small size, is easily implemented on silicon-based waveguides, and is simple in design, making it widely applicable in various fields such as chaotic secure optical communication.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure, characterized in that: It includes a first DFB chip (1), a second DFB chip (6), a Y-shaped waveguide (4), a micro-ring waveguide (3), a first transmission waveguide (2), a second transmission waveguide (7), and a feedback end face (8); wherein, the Y-shaped waveguide (4) is formed by connecting one end of the first branch, the second branch, and the bus waveguide (5) together, and its shape is Y-shaped; One end face of the first DFB chip (1) is connected to one end of the first transmission waveguide (2), and the other end of the first transmission waveguide (2) is connected to the first branch of the Y-type waveguide; one end of the second transmission waveguide (7) is provided with a feedback end face (8), and the other end is connected to the second branch of the Y-type waveguide; the bus waveguide (5) of the Y-type waveguide (4) is connected to one end face of the second DFB chip (6); The micro-ring waveguide (3) is disposed between the first transmission waveguide (2) and the second transmission waveguide (7). One side of the micro-ring waveguide (3) is coupled to the first transmission waveguide (2) in coupling region a, and the other side of the micro-ring waveguide (3) is coupled to the second transmission waveguide (7) in coupling region b.

2. The integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: It also includes a silicon substrate (9), and the first DFB chip (1), the second DFB chip (6), the Y-type waveguide (4), the micro-ring waveguide (3), the first transmission waveguide (2), the second transmission waveguide (7) and the feedback end face (8) are all disposed on the silicon substrate (9).

3. The integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: The free emission wavelength of the first DFB chip (1) and the second DFB chip (6) is 1550nm, and the light-emitting end faces at both ends are natural dissociation surfaces.

4. The integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: The splitting ratio of the two branches of the Y-shaped waveguide (4) is 1:1, and the included angle is 4°.

5. An integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: The reflectivity of the feedback end face (8) is 0.

2.

6. The integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: The first transmission waveguide (2), the second transmission waveguide (7), and the bus waveguide (5) are parallel to each other.

7. An integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: In coupling region a, the distance between the first transmission waveguide (2) and the micro-ring waveguide (3) is less than 0.1 μm. In coupling region b, the distance between the second transmission waveguide (7) and the micro-ring waveguide (3) is less than 0.1 μm.

8. An integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: The micro-ring waveguide (3) is circular with a radius of 0.5~0.7μm.

9. An integrated chaotic signal generator based on a Y-type waveguide and a single micro-ring structure according to claim 1, characterized in that: The coupling efficiency between the first transmission waveguide (2) and the micro-ring waveguide (3) is 60%, and the coupling efficiency between the second transmission waveguide (7) and the micro-ring waveguide (3) is 60%.

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