阅读说明：本技术 光子晶体全光“与/或非”逻辑门 (Photonic crystal all-optical AND/OR-NOR logic gate ) 是由 原瑞花 于 2021-08-18 设计创作，主要内容包括：本发明涉及光子晶体全光“与/或非”逻辑门,包括光子晶体结构、光信号输入端A、光信号输入端B、光信号输出端A和光信号输出端B。光子晶体结构为(2k+1)*(2k+7)的阵列结构,k为不小于2的整数。以光子晶体结构的中心孔为中心,中心孔左上45度及右下45度沿线上的空气孔的半径为r1,其余空气孔的半径为r2。2k个半径为r1的空气孔形成一个斜列,该斜列的左端与光信号输入端A相连,右端与光信号输出端B相连。光信号输出端A与光信号输入端A对称设置。光信号输入端B与光信号输出端B对称设置。该逻辑门在二维硅基平板上采用光子晶体方向带隙辐射原理,实现了全光与及或非功能,具有尺寸小,结构简单,无源低功耗等特点。(The invention relates to a photonic crystal all-optical AND/OR-NOT logic gate which comprises a photonic crystal structure, an optical signal input end A, an optical signal input end B, an optical signal output end A and an optical signal output end B. The photonic crystal structure is an array structure of (2k +1) × (2k +7), and k is an integer not less than 2. The center hole of the photonic crystal structure is taken as a center, the radius of the air holes along the line of 45 degrees at the upper left and 45 degrees at the lower right of the center hole is r1, and the radius of the rest air holes is r 2. The 2k air holes of radius r1 form a slant column, the left end of which is connected to the optical signal input terminal a and the right end of which is connected to the optical signal output terminal B. The optical signal output end A and the optical signal input end A are symmetrically arranged. The optical signal input end B and the optical signal output end B are symmetrically arranged. The logic gate adopts the photonic crystal directional band gap radiation principle on a two-dimensional silicon-based flat plate, realizes the all-optical AND/OR function, and has the characteristics of small size, simple structure, no source, low power consumption and the like.)

1. A photonic crystal all-optical AND/OR-NOT logic gate comprises a photonic crystal structure, an optical signal input end A, an optical signal input end B, an optical signal output end A and an optical signal output end B; the method is characterized in that: the photonic crystal structure is an array structure of (2k +1) × (2k +7), and k is an integer not less than 2; taking a central hole of the photonic crystal structure as a center, wherein the radius of air holes along the lines of 45 degrees at the upper left and 45 degrees at the lower right of the central hole is r1, and the radius of the rest air holes is r 2; 2k air holes with radius r1 form an oblique column, the left end of the oblique column is connected with the optical signal input end A, and the right end of the oblique column is connected with the optical signal output end B; the optical signal output end A and the optical signal input end A are symmetrically arranged and are positioned on the right side of the photonic crystal structure; the optical signal input end B and the optical signal output end B are symmetrically arranged and are positioned on the left side of the photonic crystal structure.

2. The photonic crystal all-optical and/or nor logic gate of claim 1, wherein: the photonic crystal structure adopts a silicon material flat plate with the thickness of 220nm, and the photonic crystal is a square lattice; assuming that the lattice constant is a, r1 is 0.24a and r2 is 0.36 a.

3. The photonic crystal all-optical and/or nor logic gate of claim 2, wherein: the optical signal input end A, the optical signal output end A, the optical signal input end B and the optical signal output end B are all waveguides with the width of 2 a.

4. The photonic crystal all-optical and/or nor logic gate of claim 1, wherein: the optical signal output end A has optical reduction frequency within the range of 0.3138-0.3214, and when the input energy of the optical signal input end A and/or the optical signal input end B is 0dB, the logic gate is an AND gate.

5. The photonic crystal all-optical and/or nor logic gate of claim 1, wherein: the optical signal output end B has optical reduction frequency in the range of 0.2938-0.3014 and 0.3066-0.3143, and the logic gate is NOR gate when the input energy of the optical signal input end A and/or the optical signal input end B is 0 dB.

Technical Field

The invention relates to the technical field of integrated optics, in particular to a photonic crystal all-optical AND/OR-NOR logic gate.

Background

In recent years, Photonic Crystals (PCs for short) have unique dispersion properties and effective control capability on light, and meanwhile, Photonic Crystals have the characteristics of similar size and wavelength and easy integration, so that the design and application of Photonic Crystals in the aspect of miniaturization of integrated optical circuits are widely concerned by scholars at home and abroad. Since the appearance of photonic crystals as a photonic semiconductor material, they have played no alternative role in the plenophotonics of information processing technology and the integration of photonic technology. Photonic crystals have been witnessed for their ability to manipulate light, and many designs for related applications have been proposed, and it is assumed that photonic crystals can be used to implement the functions of electronic devices, and if these devices are integrated on a semiconductor substrate to form an integrated optical circuit, the required system size is greatly reduced, and applications similar to those of integrated circuits are obtained.

As the most basic functional unit in the all-optical processing and computing network, an all-optical logic gate is similar to a gate circuit in an integrated circuit, is a unit for realizing basic logic operation and complex logic operation on an optical signal, and is a key device for realizing high-speed optical packet switching, data encoding, all-optical address recognition, signal regeneration, parity check, optical computation and future high-speed large-capacity all-optical signal processing. The all-optical logic gate has the similar structure characteristics to the gate circuit, and has two or more input ends and one output end, and the signals at the input ends and the output ends are optical signals. From a logical perspective, each input or output has only two states, "0" or "1", which are generally defined as the high or low intensity of light at the input or output for an optical signal, and can also be defined as the state of a particular transmission, optical polarization mode. Therefore, the research on the passive all-optical logic gate of the two-dimensional silicon-based slab photonic crystal not only has important guiding significance on the application of the passive all-optical logic gate in all-optical signal processing and integrated all-optical functional devices, but also accords with the policy guidance of 'increasing the research and development strength of basic materials' and 'supporting the development of dual-purpose technology for military and civilian'.

At present, the common schemes for realizing all-optical logic gates include methods based on nonlinear optical fibers, semiconductor optical amplifiers and photonic crystals. The nonlinear optical fiber-based method has good stability, but is difficult to integrate; the method based on the semiconductor optical amplifier is easy to integrate, but is easily influenced by spontaneous radiation during working, and the response time can only reach nanosecond level; the method based on the photonic crystal has the advantages of high response speed, high integration level, compact structure and the like, and plays an important role in miniaturization of an optical logic gate in an integrated optical path. The main methods for realizing the logic gate based on the photonic crystal include the technologies of auto-collimation effect, multimode interference effect, nonlinear effect and the like. The self-collimating beam gate needs to arrange a phase shifter at the input end of the gate to realize logic operation, which results in larger device size; the multimode interference logic gate has different coupling lengths for different logic gates and needs to be accurately controlled, so that the structure of the multimode interference logic gate becomes complicated, and the process difficulty is increased; photonic crystal logic gates based on nonlinear materials have high contrast of logic "1" and logic "0", but their application is limited due to high power consumption, long interaction time, etc.

Disclosure of Invention

The invention aims to provide a photonic crystal all-optical AND/OR-NOT logic gate, which solves the problems existing in the prior art for realizing the logic gate based on the photonic crystal, adopts the photonic crystal directional band gap radiation principle on a two-dimensional silicon-based flat plate, realizes all-optical AND-NOT, and has the characteristics of small size, simple structure, low power consumption, and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

a photonic crystal all-optical AND/OR-NOT logic gate comprises a photonic crystal structure, an optical signal input end A, an optical signal input end B, an optical signal output end A and an optical signal output end B.

The photonic crystal structure is an array structure of (2k +1) × (2k +7), and k is an integer not less than 2; taking a central hole of the photonic crystal structure as a center, wherein the radius of air holes along the lines of 45 degrees at the upper left and 45 degrees at the lower right of the central hole is r1, and the radius of the rest air holes is r 2; 2k air holes with radius r1 form an oblique column, the left end of the oblique column is connected with the optical signal input end A, and the right end of the oblique column is connected with the optical signal output end B; the optical signal output end A and the optical signal input end A are symmetrically arranged and are positioned on the right side of the photonic crystal structure; the optical signal input end B and the optical signal output end B are symmetrically arranged and are positioned on the left side of the photonic crystal structure.

Furthermore, the photonic crystal structure adopts a silicon material flat plate with the thickness of 220nm, and the photonic crystal is a square lattice; assuming that the lattice constant is a, r1 is 0.24a and r2 is 0.36 a.

Further, the optical signal input end a, the optical signal output end a, the optical signal input end B and the optical signal output end B all adopt waveguides with a width of 2 a.

Furthermore, under a certain optical reduction frequency range, the function of logical gate AND or NOR can be realized by regulating and controlling the optical signal input end A or/and the optical signal input end B in the photonic crystal structure. Specifically, when the optical reduction frequency of the optical signal output terminal A3 is in the range of 0.3138-0.3214 and the optical signal input terminal a2 and/or the optical signal input terminal B4 is 0dB, the logic gate is an and gate. The effect of the logical AND gate is that the output is in a high output state only when both input channels are active, and the output is in a low output state when a single input channel is active or no channel is active. The optical signal output end B5 has an optical reduction frequency in the range of 0.2938-0.3014 and 0.3066-0.3143, and the logic gate is a NOR gate when the optical signal input end A2 and/or the optical signal input end B4 is 0 dB. The effect of a logical nor gate is that when a single input channel is active, the output is in a high output state, while when both input channels are active or no channels are active, the output is in a low output state.

Compared with the prior art, the invention has the advantages that:

(1) compared with a photonic crystal all-optical logic gate in the prior art, the photonic crystal all-optical logic gate is smaller in size, the redundant photonic crystal area is structurally removed, and the whole structure is more compact; the photonic crystal slant column connecting the optical signal input end A and the optical signal output end B can be regarded as a passage, and the logic function is not realized through the microcavity structure any more.

(2) The logic gate has stronger function, the difference between the single input signal and the double input signal of the logic NOR gate is reduced from about one-half of 27 to about one-half of 92, and the blocking effect is more obvious.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a table of input two-terminal optical inputs versus logic function;

fig. 3 is a light intensity diagram of an optical signal output terminal a for implementing two all-optical logic gates according to the present invention;

fig. 4 is a light intensity diagram of the optical signal output terminal B for implementing two all-optical logic gates according to the present invention.

Wherein:

1. the photonic crystal structure comprises 2 photonic crystal structures, 2 optical signal input ends A and 3, optical signal output ends A and 4, optical signal input ends B and 5, optical signal output ends B and 6, air holes with the radius of r2, 7 air holes with the radius of r1, and 8 central holes of the photonic crystal structures.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

the photonic crystal all-optical and/or nor logic gate shown in fig. 1 comprises a photonic crystal structure 1, an optical signal input end a2, an optical signal input end B4, an optical signal output end A3 and an optical signal output end B4.

The photonic crystal structure 1 adopts a silicon material flat plate with the thickness of 220nm, the photonic crystal of the photonic crystal structure is a square lattice, and the lattice constant is a. The photonic crystal structure is an array structure of (2k +1) × (2k +7), k is an integer not less than 2, the array structure is a rectangle, wherein 2k +1 is the number of air holes in the direction of a horizontal axis, and 2k +7 is the number of air holes in the direction of a vertical axis. The snack pitch between all the squares in the array structure is equal.

The number of the air holes of the photonic crystal structure is odd in the transverse direction and the longitudinal direction, the center hole 8 of the photonic crystal structure is used as the center, the radius of the air holes along the line of 45 degrees at the upper left and 45 degrees at the lower right of the center hole 8 is r1, and the radius of the rest air holes is r 2. The central hole 8 also has a radius r 2. Preferably, r1 is 0.24a and r2 is 0.36 a. The 2k air holes 7 with radius r1 are evenly distributed on both sides of the central hole 8.

The 2k air holes 7 with radius r1 form a slanted row with the left end connected to the optical signal input terminal a2 and the right end connected to the optical signal output terminal B5. The optical signal output end A3 and the optical signal input end A2 are symmetrically arranged about the longitudinal column where the central hole is located, and the optical signal output end A3 is located on the right side of the photonic crystal structure 1 and connected with the photonic crystal structure 1. The optical signal input end B4 and the optical signal output end B5 are symmetrically arranged about the longitudinal column where the central hole 8 is located, and the optical signal input end B4 is located on the left side of the photonic crystal structure 1 and connected with the photonic crystal structure 1.

Further, the optical signal input end a2, the optical signal output end A3, the optical signal input end B4 and the optical signal output end B5 all adopt a waveguide with a width of 2 a.

Under a certain optical reduction frequency range, the function of a logic AND gate is realized by regulating and controlling the optical signal input end a or/and the optical signal input end b in the photonic crystal structure.

For optical signal output a:

when the two input light reduction frequencies are 0.3046d/λ (e.g., the lattice constant d is 472.13nm when the light wavelength λ is 1550 nm), the input energy to the optical signal input terminal a or b is 0dB, the output energy measured at the optical signal output terminal a is-38.69 dB, while the input energy to the optical signal input terminals a and b of the all-optical logic gate is also 0dB, and the output energy measured at the optical signal output terminal a is-36.75 dB. The difference between the single input signal and the double input signal is +1.94dB, which is about 1.56 times, and the function of a logic AND gate is achieved.

For optical signal output B:

when the two input light reduction frequencies are 0.2962d/λ (e.g., the lattice constant d is 459.11nm when the light wavelength λ is 1550 nm), the input energy to the optical signal input terminal a or B is 0dB, the output energy measured at the optical signal output terminal B is-22.29 dB, while the input energy to the optical signal input terminals a and B of the all-optical logic gate is also 0dB, and the output energy measured at the optical signal output terminal B is-19.63 dB. The difference between the single input signal and the double input signal is +2.66dB, which is about 1.85 times, and the function of a logic AND gate is achieved.

When the two input light reduction frequencies are 0.3082d/λ (e.g., the lattice constant d is 477.71nm when the light wavelength λ is 1550 nm), the input energy to the optical signal input terminal a or B is 0dB, the output energy measured at the optical signal output terminal B is-43.19 dB, while the input energy to the optical signal input terminals a and B of the all-optical logic gate is also 0dB, and the output energy measured at the optical signal output terminal B is-38.56 dB. The difference between the single input signal and the double input signal is +4.63dB, which is about 2.9 times, and the function of a logic AND gate is achieved.

Under a certain optical reduction frequency range, the function of a logic NOR gate is realized by regulating and controlling the optical signal input end a or/and the optical signal input end b in the photonic crystal structure.

For optical signal output terminal A

When the two input light reduction frequencies are 0.3186d/λ (e.g., the lattice constant d is 493.83nm when the wavelength λ of the light is 1550 nm), the input energy to the optical signal input terminal a or B is 0dB, the output energy measured at the optical signal output terminal B is-16.23 dB, while the input energy to the optical signal input terminals a and B of the all-optical logic gate is also 0dB, and the output energy measured at the output waveguide a is-35.89 dB. The difference between the single input signal and the double input signal is-19.66 dB, and is about one-half 92, and the function of a logic NOR gate is achieved.

Light is input from two ends of the optical signal input end A and the optical signal input end B, and when the wavelength of the input light meets the specific reduced frequency a/lambda, the light intensity of the output end can be influenced by the state of light at the input end. The logic function of the logic gate of the present invention is realized by the relationship that the intensity of light at a reduced frequency measured at an output terminal is determined by the presence or absence of light input at the input terminals, and the specific relationship is shown in fig. 2. Fig. 3 illustrates the output light intensity at different reduction frequencies received by the output terminal a when only the input terminal a is incident, only the input terminal B is incident, and the input terminal AB is simultaneously incident. Fig. 4 illustrates the case where the output B receives the output light intensity at different reduced frequencies in three cases of only the input a side light, only the input B side light, and the input AB both sides light simultaneously. The input light of the optical signal input end A and the input light of the optical signal input end B both adopt infrared light waves with the wavelength of 1550nm in communication wave band. As can be seen from fig. 3 and 4, the present invention can implement logic functions in some specific frequency ranges, and the effect of the logic functions is more obvious.

Chinese patent CN 108181773a discloses an all-optical controllable and/or logic gate of photonic crystal, which has the disadvantages of large device size, high logic function index, etc. In order to reduce the size of the device, the invention learns that the two air hole-free waveguide areas on the right side of the original structure do not directly influence the logic function by paying creative labor, removes the two air hole-free waveguide areas on the right side of the original structure to obviously reduce the size of the device in the input and output directions, and designs the structure of the logic gate by paying creative labor at the same time to ensure that the logic function can be realized after removal and the logic function effect is greatly improved, and the specific form of the structural logic function cannot be deduced by purely depending on the common knowledge and the common technical means. Through logic function simulation, it can be seen that the logic gate structure of the present invention is significantly different from chinese patent CN 108181773a in terms of frequency range for implementing logic function, logic function type and logic function index, taking the output a channel of two structures as an example, the output a channel of chinese patent CN 108181773a only has and logic output when changing input frequency, while the present invention can simultaneously output and nor logic. In addition, the difference between the single input signal and the double input signal of the logic NOR gate in the structure is reduced from about one-half of 27 to about one-half of 92, and the blocking effect is more obvious. This phenomenon is not only empirically derived, but is achieved with creative efforts.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.