Structure and implementation method of mode division multiplexing and wavelength division multiplexing optical matrix-vector multiplication unit based on photosensitive silicon

Abstract

The invention provides a calculation implementation method of a mode division multiplexing and wavelength division multiplexing optical matrix-vector multiplication unit based on photosensitive silicon. Systems and methods for optical matrix-vector multiplication using mode division multiplexing and microring resonators are provided. Examples of the systems and methods disclosed herein include an array of structures based on mode division multiplexing and microring resonators, a phase change material, and a waveguide. An operation representing a matrix multiplied by a vector may be generated based on the optical power output from the array of microring resonator structures.

Description

Technical Field

[0001] The present invention relates to the field of photon computing, and in particular to a structure and implementation method of an optical matrix-vector multiplication unit based on mode division multiplexing and wavelength division multiplexing. Background Art

[0002] Photonic computing architectures, with their high speed and parallelism, offer significant advantages in processing linear computations, making them a hot topic of international research. Photonic neural network processors, centered around optical multiplication, are particularly attracting attention. With the advent of the artificial intelligence and big data era, the demand for high computing performance and compact size in photonic chips is increasing. Compared to electronic systems, photonic systems exhibit improved performance in multiplexing, energy dissipation, and crosstalk, which is beneficial for dense, high-bandwidth interconnects.

[0003] Compared to electronic systems, optical computing has higher computing speed and efficiency, and can save a lot of power. Therefore, storing weight values ​​in non-volatile phase-change materials and performing calculations directly can significantly reduce the increased power consumption and decreased efficiency caused by the data transfer process between storage and calculation. Summary of the Invention

[0004] To address the aforementioned technical issues, the present invention specifically adopts the following technical solution: a structure and implementation method for a photosensitive silicon-based mode division multiplexing and wavelength division multiplexing optical matrix-vector multiplication unit, characterized in that it includes n×n matrix-vector multiplication units, each of which is composed of a mode demultiplexer, a phase change material unit, a microring resonator unit, and a waveguide. The optical matrix-vector multiplication unit uses integrated optics to implement multiplication operations of an n×n matrix and an n×1 vector, where the elements in the n×n matrix are real numbers between 0 and 1, the elements in the n×1 vector are arbitrary real numbers, and m and n are natural numbers greater than or equal to 2.

[0005] The mode demultiplexer unit is composed of a mode demultiplexer, benefiting from the mode division multiplexing and wavelength division multiplexing technology, including n modes and n wavelengths λ1-λ nThe input signal can be orthogonally transmitted in the bus waveguide and then demultiplexed into the matrix multiplication vector array on the right. The optical signal of the wavelength that satisfies the resonance equation of the microring resonator unit A is output from the download end of the microring resonator unit A, and then enters the phase change material unit B through the waveguide. The m phase change material units are composed of phase change material. The optical signal output from the download end of the microring resonator unit A passes through the m phase change material units B and enters the input end of the microring resonator unit C. The microring resonator unit C is consistent with the resonance equation satisfied by the microring resonator unit A. The optical signal output from the phase change material unit B passes through the microring resonator unit C, and then is output from the download end of the microring resonator unit C into the vertical bus waveguide to obtain the output optical signal multiplied by the weight.

[0006] The material of the phase change material unit is photosensitive silicon, and its characteristic is that when light of different intensities is irradiated on the surface of the photosensitive silicon, the photosensitive silicon exhibits different transmittances. Based on this property, its transmittance can be adjusted according to the intensity of the light irradiated on its surface, thereby achieving the setting of the weight w value between 0-1.

[0007] The function realization process of the optical matrix-vector multiplication unit is as follows: the input signal is n different wavelengths λ1, λ2, ..., λ n Each wavelength of the optical signal has n modes. After entering the demultiplexer, it is demodulated into n modes of optical signals. Each mode contains n wavelengths of optical signals. The modulation signals on it are x1, x2, and x3. 2， …, x n The optical signal of the corresponding wavelength that satisfies the resonance equation of the microring resonator unit A will be screened out and output as a single wavelength optical signal from the download section of the microring resonator unit A, and then enter the phase change material unit B, and pass through a selected phase change material w 11 Then, w is output from the output end of the phase change material unit. 11 The x1 signal enters the input of microring resonator unit C. Since microring resonator unit C satisfies the same resonance equation as microring resonator unit A, the optical signal is output from the output terminal of microring resonator unit C, enters the vertical bus waveguide, and propagates upward. Finally, the detector adds the output results to obtain the result of the optical matrix-vector multiplication operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a structural schematic diagram of the present invention.

[0009] Figure 2 It is a schematic diagram of the 2×2 matrix and 2×1 vector multiplication operation of the present invention.

[0010] Figure 3 It is a schematic structural diagram of the silicon-based microring resonator of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of the present invention more concise and clear, the specific embodiments of the present invention will be described in more detail below with reference to schematic diagrams. The advantages and features of the present invention will become clearer based on the following description and claims. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in illustrating the purpose of the embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0012] The principle of matrix multiplication is to implement the multiplication operation between an input matrix a and an input vector b, and obtain the output vector c. The specific calculation formula is as follows:

[0013]

[0014] When m=n, the input matrix a is a block matrix, also called a square matrix. Figure 1 As shown, the present invention can implement the above block matrix-vector multiplication operation.

[0015] Figure 2 The figure is a schematic diagram of an embodiment of a 2×2 matrix and 2×1 vector multiplication operation of the matrix-vector multiplication operation unit. The present invention is described in detail below in conjunction with the embodiments and drawings.

[0016] The multiplication formula of a 2×2 matrix and a 2×1 vector is as follows:

[0017]

[0018] like Figure 2 As shown, the optical matrix-vector multiplication operation unit is integrated on the silicon substrate, which includes 4 groups of independent operation units, specifically microring resonator units A1-A4, phase change material units B1-B4 and microring resonator units C1-C4. On the left side, optical signals of two modes, TE0 and TE1, are input into the bus waveguide, and both optical signals of TE0 and TE1 modes contain two wavelengths, λ1 and λ2; the optical signal passes through the demultiplexer to separate the optical signals of the two modes, and after the input signal of mode TE0 passes through the microring resonator unit A1, the signal with a wavelength of λ1 that satisfies the resonance equation of the microring resonator in the microring resonator unit A1 is output from the download end of the microring resonator unit A1 and enters the phase change material unit B1. At this time, the signal output from the output end of the phase change material unit B1 is w 11 The signal output from the phase change material unit B1 enters the microring resonator unit C1. The resonance equation satisfied by the microring resonator unit C1 is the same as that satisfied by the microring resonator unit A1. At this time, w 11x1 is output from the download end of the microring resonator unit C1 and enters the vertical waveguide to propagate upward. Similarly, the signal output by the microring resonator unit C2 is w 21 x1, the signal output by the microring resonator unit C3 is w 12 x2, the signal output by the microring resonator unit C4 is w 22 x2. Use an optical power meter to add the output signals of microring resonator unit C1 and microring resonator unit C3, and the resulting signal is w 11 x1+w 12 x1; Use an optical power meter to add the signals output by the microring resonator unit C2 and the microring resonator unit C4, and the resulting signal is w 21 x2+w 22 x2. In this way, the obtained signal is the result of the operation of the output vector.

[0019] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art may, without departing from the scope of the technical solution of the present invention, make any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention, without departing from the technical solution of the present invention.

Claims

1. A structure and implementation method of a mode division multiplexing and wavelength division multiplexing optical matrix-vector multiplication unit based on photosensitive silicon, characterized in that: The optical matrix-vector multiplication unit comprises n×n optical multiplication units, each consisting of a mode demultiplexer, a phase-change material unit, a microring resonator unit, and a waveguide. This optical matrix-vector multiplication unit uses integrated optics to perform multiplication of an n×n matrix and an n×1 vector, where the elements of the n×n matrix are real numbers between 0 and 1, the elements of the n×1 vector are arbitrary real numbers, and m and n are natural numbers greater than or equal to 2.

2. The optical matrix-vector multiplication unit according to claim 1, characterized in that The mode demultiplexer unit comprises a mode demultiplexer, benefiting from mode division multiplexing and wavelength division multiplexing technology, including n modes and n wavelengths λ1-λ n The input signal can be orthogonally transmitted in the bus waveguide and then demultiplexed into the matrix multiplication vector array on the right. The optical signal of the wavelength that satisfies the resonance equation of the microring resonator unit A is output from the download end of the microring resonator unit A, and then enters the phase change material unit B through the waveguide. The m phase change material units are composed of phase change material photosensitive silicon. The optical signal output from the download end of the microring resonator unit A passes through the m phase change material units B and enters the input end of the microring resonator unit C. The microring resonator unit C is consistent with the resonance equation satisfied by the microring resonator unit A. The optical signal output from the phase change material unit B passes through the microring resonator unit C, and then is output from the download end of the microring resonator unit C into the vertical bus waveguide to obtain the output optical signal multiplied by the weight.

3. The optical matrix-vector multiplication unit according to claim 1, characterized in that The material of the phase change material unit is photosensitive silicon, and its characteristic is that when light of different intensities is irradiated on the surface of the photosensitive silicon, the photosensitive silicon exhibits different transmittances. Based on this property, its transmittance can be adjusted according to the intensity of the light irradiated on its surface, thereby achieving the setting of the weight w value between 0-1.

4. The optical matrix-vector multiplication unit according to claim 1, characterized in that The function realization process of the optical matrix-vector multiplication unit is as follows: the input signal is n different wavelengths λ1, λ2, ..., λ n Each wavelength of the optical signal has n modes. After entering the demultiplexer, it is demodulated into n modes of optical signals. Each mode contains n wavelengths of optical signals. The modulation signals on it are x1, x2, and x3. 2， …, x n The optical signal of the corresponding wavelength that satisfies the resonance equation of the microring resonator unit A will be screened out and output as a single wavelength optical signal from the download section of the microring resonator unit A, and then enter the phase change material unit B, and pass through a selected phase change material w 11 Then, w is output from the output end of the phase change material unit. 11 The x1 signal enters the input of microring resonator unit C. Since the resonance equation satisfied by microring resonator unit C is the same as that of microring resonator unit A, the optical signal is output from the output end of microring resonator unit C, enters the vertical waveguide, and propagates upward. Finally, the detector adds the output results to obtain the result of the optical matrix-vector multiplication operation.

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