Optical nonlinear device based on Y branch

Abstract

The invention provides an optical nonlinear device based on a Y branch, and relates to the technical field of microwave photonics. The optical nonlinear device comprises a Y-branch left output waveguide, a Y-branch right output waveguide, a gain regulation and control unit, a phase regulation and control unit, a Y-branch beam splitter and an input waveguide, the input waveguide is used for inputting an optical signal to be modulated, and the optical signal to be modulated is divided into two paths after sequentially passing through the gain regulation and control unit and the Y-branch beam splitter, modulated optical signals are output from the Y-branch left side output waveguide and the Y-branch right side output waveguide respectively; the Y-branch left output waveguide and the Y-branch right output waveguide are respectively provided with a gain regulation and control unit and a phase regulation and control unit. By utilizing the characteristics of large bandwidth, low time delay and low power consumption of photon information processing, high-speed nonlinear conversion can be realized in an optical domain, and meanwhile, the scheme can realize regulation and control of input and output light intensity response curves and has the advantage of integration.

Description

Technical Field

[0001] The invention relates to the technical field of microwave photonics, and in particular to an optical nonlinear device based on Y-branching. Background Art

[0002] The optical FP resonant cavity, referred to as the FP cavity, also called the FP etalon or FP interferometer, is a device that works by using the multi-beam interference phenomenon. It was originally invented by French physicists Fabry and Perot in 1987. It has been widely used in many fields of laser and precision spectral measurement and is a common instrument in optical laboratories. The FP cavity is composed of two mirrors with high reflectivity. The uniform plane wave propagates back and forth in the FP cavity along the axis. When the wave is reflected on the cavity mirror, the incident wave and the reflected wave will interfere constructively, and multiple round trips will cause multi-beam interference. The light propagates stably in the cavity.

[0003] Parity-time symmetry (PT symmetry) originates from non-Hermitian physics. In quantum mechanics theory, closed systems are described by Hermitian Hamiltonians, whose eigenvalues ​​are real numbers and whose eigenvectors are mutually orthogonal. Non-Hermitian Hamiltonians describe open systems, that is, systems that exchange energy with their surroundings. Their eigenvalues ​​are complex numbers and their eigenvectors are non-orthogonal. In 1998, Bender discovered that under the conditions of parity-time reversal symmetry, non-Hermitian Hamiltonians also have real eigenvalues, which brought a milestone development to the study of non-Hermitian physics. In 2007, R. El-Ganainy proposed the construction of a PT-symmetric optical system using the mathematical isomorphism between the optical paraxial wave equation and the Schrödinger equation. The optical system then became an ideal platform for studying non-Hermitian physics, which quickly triggered research hotspots in related fields.

[0004] Optical neural networks are one of the hottest research directions at present, and are the most promising representative solutions to break through the von Neumann bottleneck and the bottleneck of the slowdown of Moore's Law. In the neural network model, some form of nonlinearity is needed to realize the threshold of the neuron, respond to multiple optical inputs, and produce outputs suitable for driving other optical neurons, such as nonlinear activation functions. In this context, realizing pure optical nonlinear response is an important topic in modern optical research. Summary of the invention

[0005] In view of the above problems, the present invention provides an optical nonlinear device based on Y-branching.

[0006] The present invention provides an optical nonlinear device based on a Y-branch, comprising 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 to input an optical signal to be modulated, the optical signal to be modulated is divided into two paths after passing through the gain control unit and the Y-branch beam splitter in sequence, and the modulated optical signals are outputted from the Y-branch left-side output waveguide and the Y-branch right-side output waveguide respectively; the Y-branch left-side output waveguide and the Y-branch right-side output waveguide are respectively provided with a gain control unit and a phase control unit.

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

[0008] Furthermore, the Y-branch left output waveguide and the Y-branch right output waveguide respectively use silicon waveguide, lithium niobate waveguide or silicon nitride waveguide.

[0009] Furthermore, the output waveguide on the left side of the Y branch and the output waveguide on the right side of the Y branch are respectively coated with optical films at the output ends; wherein, when the incident light passes through the optical film, a part of it is transmitted and output, and a part of it is reflected back to the Y branch, the incident light and the reflected light interfere with each other and multi-beam interference occurs after multiple round trips, and finally a FP coupling structure is formed.

[0010] Furthermore, 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 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, thereby realizing the optical nonlinear function.

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

[0012] Furthermore, optical nonlinear devices are implemented on a silicon photonics platform through semiconductor processes.

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

[0014] (1) Taking advantage of the large bandwidth, low latency, and low power consumption of photonic information processing, high-speed nonlinear conversion with high parallelism can be achieved in the optical domain.

[0015] (2) By adjusting the parameters of the gain control unit and the phase control unit, the input and output light intensity response curves can be controlled, making them controllable.

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

[0017] Wavelength: 1550nm band;

[0018] Phase shift range: 0~2π;

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

[0020] FSR range: 100GHz.

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

[0022] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0023] Figure 1 The structure of an optical nonlinear device based on Y-branch according to an embodiment of the present invention is schematically shown.

[0024] Description of reference numerals:

[0025] 1-Y branch left output waveguide

[0026] 2-Y branch right 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] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the 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 (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0034] Figure 1 The structure of an optical nonlinear device based on Y-branch according to an embodiment of the present invention is schematically shown.

[0035] like Figure 1 As shown, the Y-branch-based optical nonlinear device of this 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 to input the optical signal to be modulated. 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 sequence. The modulated optical signals are output from the Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 respectively.

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

[0038] In the embodiment of the present invention, 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-optic phase modulator or a thermo-optic phase modulator. In other embodiments, the gain control unit 3 may also adopt other devices that can adjust the light intensity; the phase control unit 4 may also adopt other devices that can adjust the light phase.

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

[0040] In an embodiment of the present invention, the Y-branch left output waveguide 1 and the Y-branch right output waveguide 2 are respectively coated with optical films at the output ends; wherein, when the incident light passes through the optical film, a portion is transmitted and output, and a portion is reflected back to the Y branch, the incident light and the reflected light interfere with each other and multi-beam interference occurs after multiple round trips, and finally an FP coupling structure is formed.

[0041] Specifically, when 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 will interfere with each other, and multiple round trips will cause multi-beam interference, and the entire system will form a FP coupling structure.

[0042] In the embodiment of the present invention, 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 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 the optical nonlinear function.

[0043] Specifically, when the optical gain in the FP coupling structure is greater than the optical loss, it is manifested as a net gain; when the optical gain in the FP coupling structure is less than the optical loss in the ring, it is manifested as a net loss. When one of the branches is controlled to be a net gain and the other branch is manifested as a 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 a critical state of parity-time symmetry breaking, at which time the output light intensity of the Y branch left output waveguide 1 and the Y branch right output waveguide 2 changes nonlinearly with the increase of the input light intensity of the input waveguide 6, thereby realizing an optical nonlinear function.

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

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

[0046] In summary, an embodiment of the present invention provides an optical nonlinear device based on a Y branch, 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. Among them, the input waveguide 6 is used to input 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 sequence, 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 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 the optical nonlinear function. The present invention utilizes the characteristics of large bandwidth, low latency and low power consumption of photon information processing, and can realize high-speed nonlinear conversion in the optical domain. At the same time, the scheme can realize the controllable input and output light intensity response curves, and has the advantage of integration.

[0047] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of the present invention. In addition, the shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual size, proportion, and actual positional relationship.

[0048] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical nonlinear device based on Y-branching, characterized in that: It comprises 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 a Y-branch left output waveguide (1) and a Y-branch right output waveguide (2) respectively. The Y-branch left-side output waveguide (1) and the Y-branch right-side output waveguide (2) are respectively provided with a gain control unit (3) and a phase control unit (4).

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-optic phase modulator or a thermo-optic 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) are respectively made of 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, and finally a FP coupling structure is formed.

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 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 as the intensity of the optical signal to be modulated input by the input waveguide (6) increases, thereby realizing an optical nonlinear function.

6. The optical nonlinear device based on Y-branching according to claim 5, 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.

7. 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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