Optical nonlinear device based on y-branch

Abstract

The application provides a kind of optical nonlinear device based on Y branch, and relates to the technical field of microwave photonics.The optical nonlinear device includes Y branch left side output waveguide, Y branch right side output waveguide, gain control unit, phase control unit, Y branch beam splitter and input waveguide, wherein: the input waveguide is used to input the light signal to be modulated, the light signal to be modulated is divided into two paths after passing through gain control unit and Y branch beam splitter in turn, and the modulated light signal is output from Y branch left side output waveguide and Y branch right side output waveguide respectively; gain control unit and phase control unit are respectively arranged on Y branch left side output waveguide and Y branch right side output waveguide.The application utilizes the characteristics of large bandwidth, low delay and low power consumption of photonic information processing, can realize high-speed nonlinear conversion in optical domain, and the scheme can realize adjustable input and output light intensity response curve, and has the advantage of integration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave photonics, and particularly relates to an optical nonlinear device based on a Y branch. BACKGROUND

[0002] The optical F-P resonant cavity, referred to as F-P cavity, F-P etalon or F-P interferometer, is a device working by utilizing the phenomenon of multiple-beam interference. It was invented by French physicists Fabry and Perot in 1987 and has been widely applied to the fields of laser and precise spectrum measurement, and is a commonly used instrument in optical laboratories. The F-P cavity is composed of two mirror surfaces with high reflectivity. A uniform plane wave propagates back and forth in the F-P cavity along the axial direction, and when the wave is reflected on the cavity mirror, the incident wave and the reflected wave will interfere constructively, and multiple-beam interference will occur after multiple back-and-forth transmissions. The light realizes stable propagation in the cavity.

[0003] Parity-time symmetry (PT symmetry) originates from non-Hermitian physics. In quantum mechanics, a closed system is described by a Hermitian Hamiltonian, whose eigenvalues are real numbers and the eigenvectors are mutually orthogonal. A non-Hermitian Hamiltonian describes an open system, i.e. a system that exchanges energy with the surrounding environment, whose eigenvalues are complex numbers and the eigenvectors are not orthogonal. In 1998, Bender found that under the condition of parity-time inversion symmetry, the non-Hermitian Hamiltonian also has real eigenvalues, which brought a milestone development to the study of non-Hermitian physics. In 2007, R. El-Ganainy proposed to construct a PT symmetric optical system by using the mathematical isomorphism between the optical paraxial wave equation and the Schrodinger equation, and the optical system became an ideal platform for studying non-Hermitian physics, which quickly triggered a research hotspot in related fields

[0004] Optical neural networks are one of the most popular research directions, and are the most promising representative scheme for breaking through the von Neumann bottleneck and the slowdown bottleneck of Moore's law. In the neural network model, a certain form of nonlinearity is needed to realize the threshold value of the neuron, to respond to multiple light inputs and to produce an output suitable for driving other optical neurons, such as a nonlinear activation function. In this context, realizing pure optical nonlinear response is an important topic in modern optical research. SUMMARY

[0005] In view of the above problems, the present application provides an optical nonlinear device based on a Y branch.

[0006] The application provides a Y-branch-based optical nonlinear device, which comprises a Y-branch left-side output waveguide, a Y-branch right-side output waveguide, a gain control unit, a phase control unit, a Y-branch beam splitter and an input waveguide, wherein the input waveguide is used for inputting a to-be-modulated optical signal; the to-be-modulated optical signal is divided into two paths after sequentially passing through the gain control unit and the Y-branch beam splitter, and the modulated optical signals are output from the Y-branch left-side output waveguide and the Y-branch right-side output waveguide respectively; and the Y-branch left-side output waveguide and the Y-branch right-side output waveguide are respectively provided with the gain control unit and the phase control unit.

[0007] Further, the gain control unit is an SOA semiconductor optical amplifier or an EDFA erbium-doped fiber amplifier; and the phase control unit is an electro-optic phase modulator or a thermo-optic phase modulator.

[0008] Further, the Y-branch left-side output waveguide and the Y-branch right-side output waveguide are respectively a silicon waveguide, a lithium niobate waveguide or a silicon nitride waveguide.

[0009] Further, the Y-branch left-side output waveguide and the Y-branch right-side output waveguide are respectively coated with an optical thin film at the output end; wherein when the incident light passes through the optical thin film, part of the incident light is transmitted and output, and part of the incident light is reflected back to the Y-branch; the incident light and the reflected light interfere with each other and multiple-beam interference occurs after multiple back-and-forth movements, and finally an F-P coupling structure is formed.

[0010] Further, the parameters of the gain control unit and the phase control unit are adjustable; wherein by adjusting the parameters of the gain control unit and the phase control unit, the optical nonlinear device can work in a critical state of parity-time symmetry breaking, so that the intensity of the modulated optical signal nonlinearly changes with the increase of the intensity of the to-be-modulated optical signal input by the input waveguide, and the optical nonlinear function is realized.

[0011] Further, the parameters of the gain control unit and the phase control unit are independently adjusted respectively, or are divided into multiple regions for regional adjustment.

[0012] Further, the optical nonlinear device is realized on a silicon optical platform through a semiconductor process.

[0013] Compared with the prior art, the Y-branch-based optical nonlinear device provided by the application has at least the following beneficial effects:

[0014] (1) By utilizing the characteristics of large bandwidth, low delay and low power consumption of photonic information processing, high parallelism of high-speed nonlinear conversion can be realized in the optical domain.

[0015] (2) By adjusting the parameters of the gain control unit and the phase control unit, the input-output optical intensity response curve can be controlled, so that the optical nonlinear device has controllability.

[0016] (3) The Y-branch-based optical nonlinear device meets the following index parameter requirements:

[0017] Wavelength: 1550nm band;

[0018] Phase shift range: 0~2pi;

[0019] Gain tuning range: 0~16dB;

[0020] FSR range: 100GHz.

[0021] (4) The Y-branch-based optical nonlinear device has the advantage of integration. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1 A structure diagram of the Y-branch-based optical nonlinear device according to the embodiment of the present application is schematically shown.

[0024] Explanation of reference numerals:

[0025] 1-Y branch left side output waveguide

[0026] 2-Y branch right side output waveguide

[0027] 3-Gain control unit

[0028] 4-Phase control unit

[0029] 5-Y branch beam splitter

[0030] 6-Input waveguide DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] The terms used herein are merely used to describe specific embodiments, and are not intended to limit the present application. The terms "comprise", "contain" and the like used herein indicate the existence of the described features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0033] All terms used herein (including technical and scientific terms) have the meaning commonly understood by one of ordinary skill in the art unless otherwise defined. It should be further noted that the use of the terms herein are intended to be interpreted in the context of the specification as a whole and should not be interpreted in an idealized or overly formal manner.

[0034] Figure 1 A structure diagram of a Y-branch-based optical nonlinear device according to an embodiment of the present application is schematically shown.

[0035] As shown in Figure 1 The Y-branch-based optical nonlinear device of the embodiment includes a Y-branch left output waveguide 1, a Y-branch right output waveguide 2, a gain control unit 3, a phase control unit 4, a Y-branch beam splitter 5 and an input waveguide 6, wherein:

[0036] The input waveguide 6 is used for inputting a to-be-modulated optical signal, the to-be-modulated optical signal passes through the gain control unit 3 and the Y-branch beam splitter 5 in sequence and is then divided into two paths, and the modulated optical signals are output from the Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 respectively.

[0037] The Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 are respectively provided with the gain control unit 3 and the phase control unit 4.

[0038] In the embodiment of the present application, the gain control unit 3 adopts a SOA semiconductor optical amplifier or an EDFA erbium-doped fiber amplifier; and the phase control unit 4 adopts an electro-optic phase modulator or a thermo-optic phase modulator. In other embodiments, the gain control unit 3 can also adopt other devices capable of adjusting optical intensity; and the phase control unit 4 can also adopt other devices capable of adjusting optical phase.

[0039] In the embodiment of the present application, the Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 respectively adopt a silicon waveguide, a lithium niobate waveguide or a silicon nitride waveguide. In other embodiments, the Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 can also adopt other feasible materials.

[0040] In the embodiment of the present application, the Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 are respectively coated with an optical thin film at the output end; wherein when the incident light passes through the optical thin film, a part is transmitted and output, and a part is reflected back to the Y-branch. The incident light and the reflected light will interfere and multiple-beam interference will occur after multiple back-and-forth, and finally an F-P coupling structure is formed.

[0041] Specifically, when the light passes through the optical thin film, a part is transmitted and output, and a part is reflected back to the Y-branch. The incident light and the reflected light will interfere, multiple-beam interference will occur after multiple back-and-forth, and the whole system will form an F-P coupling structure.

[0042] In the embodiment of the present application, the parameters of the gain control unit 3 and the phase control unit 4 are adjustable; wherein, by adjusting the parameters of the gain control unit 3 and the phase control unit 4, the optical nonlinear device can work in the critical state of the time-reversal symmetry breaking, so that the intensity of the modulated optical signal nonlinearly changes with the increase of the intensity of the input optical signal input by the input waveguide 6, and the optical nonlinear function is realized.

[0043] Specifically, when the optical gain in the F-P coupling structure is greater than the optical loss, it shows net gain; when the optical gain in the F-P coupling structure is less than the optical loss in the ring, it shows net loss. When one branch is controlled to be net gain and the other branch is net loss, and the difference between the net gain and the net loss is equal to the coupling coefficient of the Y branch beam splitter 5, the system works in the critical state of the time-reversal symmetry breaking, at this time, the output optical intensity of the Y branch left output waveguide 1 and the Y branch right output waveguide 2 nonlinearly changes with the increase of the input optical intensity of the input waveguide 6, thereby realizing the optical nonlinear function.

[0044] As preferred, the parameters of the gain control unit 3 and the phase control unit 4 can be independently adjusted respectively, and can also be divided into several small areas for regional adjustment.

[0045] In the embodiment of the present application, the optical nonlinear device is realized on a silicon optical platform through a semiconductor process, thereby reducing the spatial redundancy.

[0046] In summary, the embodiment of the present application provides a Y branch based optical nonlinear device including a Y branch left output waveguide 1, a Y branch right output waveguide 2, a gain control unit 3, a phase control unit 4, a Y branch beam splitter 5 and an input waveguide 6. Wherein, the input waveguide 6 is used for inputting the optical signal to be modulated, and the optical signal to be modulated is divided into two paths after passing through the gain control unit 3 and the Y branch beam splitter 5 in turn, and the modulated optical signal is output from the Y branch left output waveguide 1 and the Y branch right output waveguide 2 respectively. By adjusting the parameters of the gain control unit 3 and the phase control unit 4, the optical nonlinear device can work in the critical state of the time-reversal symmetry breaking, so that the intensity of the modulated optical signal nonlinearly changes with the increase of the intensity of the input optical signal input by the input waveguide 6, and the optical nonlinear function is realized. The present application utilizes the characteristics of large bandwidth, low delay and low power consumption of photonic information processing, and can realize high-speed nonlinear conversion in the optical domain. Meanwhile, the scheme can realize the adjustable response curve of input and output optical intensity, and has the advantage of integration.

[0047] In the description of the present application, it needs to be understood that the terms "upper", "lower", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in understanding the present application, the conventional structure or configuration will be omitted. And the shape, size, positional relationship of each component in the figure do not reflect the true size, proportion and actual positional relationship.

[0048] The specific embodiments described above further illustrate the objects, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An optical nonlinear device based on Y-branching, characterized in that: It includes a Y-branch left output waveguide (1), a Y-branch right output waveguide (2), a gain control unit (3), a phase control unit (4), a Y-branch beam splitter (5) and an input waveguide (6), wherein: The input waveguide (6) is used to input an optical signal to be modulated. The optical signal to be modulated is sequentially passed through a gain control unit (3) and a Y-branch beam splitter (5) and then split into two paths. The modulated optical signals are output from the Y-branch left output waveguide (1) and the Y-branch right output waveguide (2), respectively. The Y-branch left output waveguide (1) and the Y-branch right output waveguide (2) are respectively provided with a gain control unit (3) and a phase control unit (4); The parameters of the gain control unit (3) and the phase control unit (4) are adjustable; By adjusting the parameters of the gain control unit (3) and the phase control unit (4), the optical nonlinear device can be operated in a critical state of parity-time symmetry breaking, so that the intensity of the modulated optical signal changes nonlinearly with the increase of the intensity of the optical signal to be modulated input by the input waveguide (6), thereby realizing an optical nonlinear function.

2. The optical nonlinear device based on Y-branching according to claim 1, characterized in that: The gain control unit (3) adopts a SOA semiconductor optical amplifier or an EDFA erbium-doped fiber amplifier; The phase control unit (4) adopts an electro-optical phase modulator or a thermo-optical phase modulator.

3. The optical nonlinear device based on Y-branching according to claim 1, characterized in that: The Y-branch left-side output waveguide (1) and the Y-branch right-side output waveguide (2) respectively adopt silicon waveguide, lithium niobate waveguide or silicon nitride waveguide.

4. The optical nonlinear device based on Y-branching according to claim 1, characterized in that: The Y-branch left output waveguide (1) and the Y-branch right output waveguide (2) are respectively coated with optical thin films at the output ends; When the incident light passes through the optical film, part of it is transmitted and output, and part of it is reflected back to the Y branch. The incident light and the reflected light interfere with each other and after multiple round trips, multi-beam interference occurs, eventually forming an FP coupling structure.

5. The optical nonlinear device based on Y-branching according to claim 1, characterized in that: The parameters of the gain control unit (3) and the phase control unit (4) are adjusted independently, or divided into multiple regions for regional adjustment.

6. The optical nonlinear device based on Y-branching according to claim 1, characterized in that: The optical nonlinear device is realized on a silicon photonics platform through semiconductor technology.

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