CN104503184B - A kind of line electric light priority encoder of new 4 line 2 based on micro-ring resonator - Google Patents

Abstract

A novel 4-wire-2-wire electro-optic priority encoder based on microring resonators, including four microring resonators and three straight waveguides, the first straight waveguide and the second straight waveguide intersect perpendicularly to form a Cartesian coordinate system, the third The straight waveguide is parallel to the first straight waveguide; the silicon-based nanowire microring of a microring resonator is located in the fourth quadrant of the Cartesian coordinate system, and is located between the first straight waveguide and the third straight waveguide; the second microring resonator The silicon-based nanowire microring is located in the third quadrant of the Cartesian coordinate system, and the silicon-based nanowire microrings of the other two microring resonators are located in the second quadrant of the Cartesian coordinate system. The priority encoder overcomes the bottleneck problems of speed, power consumption, gate delay, competition and risk in the traditional electrical encoder, realizes high-speed and large-capacity information processing, has a good fault tolerance rate, and maintains a small device size and low power consumption. The premise of modern integrated circuits that are easy to integrate can play an important role in photonic communication and photonic information processing systems.

Description

A Novel 4-Wire-2-Wire Electro-optical Priority Encoder Based on Microring Resonator

technical field

The invention belongs to the technical field of optical communication, and relates to an electro-optic priority encoder, in particular to a novel 4-2-wire electro-optic priority encoder based on a microring resonator.

Background technique

With the continuous development of semiconductor technology, the integration of chips or integrated circuits is getting higher and higher, and the size of integrated components is further reduced. The leakage and heat dissipation problems of traditional electrical devices cannot be solved well, and the clock distortion and electromagnetic interference of the circuit are getting worse. It's getting serious. The faster processing speed required by people can no longer be obtained by electronic circuits using electrons as information carriers, while optical communication and optical computing systems use photons as information carriers, photons have no charge, and there is no electromagnetic field interaction between them. In free space, several beams of light propagate in parallel and cross each other, without interference between each other. The parallelism of optical signal transmission makes the optical system have a wider information channel than the electrical system; use optical interconnection instead of wire interconnection, photon Hardware replaces electronic hardware, and optical computing replaces electrical computing. The integrated optical path is composed of optical fibers and various optical components, which can greatly improve the ability of data computing, transmission and storage. Coupled with the low energy consumption of photonic devices, photonic devices have caused Attention of more and more researchers.

In a computer system, in order to distinguish a series of things, each of them is represented by a binary code, which is the meaning of encoding. The logic function of the encoder is to generate this sequence of binary codes. Encoders are essential elements in communication and computing networks. Optical encoders are also indispensable for optical information systems, but ordinary encoders have poor error tolerance. When multiple signals are input at the same time, confusion or wrong encoding will occur.

Contents of the invention

The purpose of the present invention is to provide a novel 4-wire-2-wire electro-optical priority encoder based on a microring resonator with a high fault tolerance rate. When multiple signals are input at the same time, the highest priority can be determined according to the priority determined in advance. The signal is encoded without confusion or wrong encoding.

In order to achieve the above object, the technical solution adopted in the present invention is: a novel 4-wire-2-wire electro-optical priority encoder based on microring resonators, including four microring resonators and three straight waveguides, the three straight waveguides The first straight waveguide and the second straight waveguide perpendicularly intersect to form a rectangular coordinate system, the third straight waveguide is parallel to the first straight waveguide, and the third straight waveguide does not intersect with the first straight waveguide; the silicon base of a microring resonator The nanowire microring is located in the fourth quadrant of the Cartesian coordinate system, and the silicon-based nanowire microring is located between the first straight waveguide and the third straight waveguide; the silicon-based nanowire microring of the second microring resonator Located in the third quadrant of the Cartesian coordinate system, the silicon-based nanowire microrings of the remaining two microring resonators are located in the second quadrant of the Cartesian coordinate system along the direction parallel to the first straight waveguide, and the two microring resonators are located in the second quadrant of the Cartesian coordinate system. The silicon-based nanowire microring of the microring resonator facing the second straight waveguide in the ring resonator is located between the first straight waveguide and the third straight waveguide.

The electro-optic priority encoder of the present invention has the following advantages:

1. Using the natural characteristics of light to realize the electro-optic encoder instead of the traditional electrical encoder, without the electromagnetic effect of traditional electrical devices and the influence of parasitic resistance and capacitance, it can realize high-speed and large-capacity information processing.

2. The silicon material SOI on the insulating substrate is used, that is, a layer of single crystal silicon film with a certain thickness is grown on the SiO ₂ insulating layer, and the silicon waveguide made of SOI material is used. The core layer is Si (refractive index 3.45 ), the cladding layer is SiO ₂ (refractive index 1.44), and the refractive index difference between the cladding layer and the core layer is very large, so the waveguide has a strong ability to confine the optical field, so that its bending radius can be small, which is conducive to large-scale integration .

3. This 4-wire-2-wire electro-optical priority encoder is only composed of a microring resonator and three straight waveguides, of which there is only one crossover, and the loss except for the microring and one crossover is negligible, so the overall device loss is very small.

4. The electro-optic priority encoder of the present invention is made by using the existing CMOS technology, the device has small volume, low power consumption, good scalability, and is easy to integrate with other components.

Description of drawings

Fig. 1 is a structural schematic diagram of the electro-optic priority encoder of the present invention.

Fig. 2 is a schematic structural diagram of the first microring resonator in the electro-optic priority encoder of the present invention.

Fig. 3 is a schematic structural diagram of the second microring resonator in the electro-optic priority encoder of the present invention.

Fig. 4 is a schematic structural diagram of the third microring resonator in the electro-optic priority encoder of the present invention.

Fig. 5 is a schematic structural diagram of the fourth microring resonator in the electro-optic priority encoder of the present invention.

Fig. 6 is a schematic structural diagram of electrodes of a microring resonator MRR with a silicon-based thermo-optic modulator in the electro-optic priority encoder of the present invention.

Fig. 7 is a schematic diagram of the electrode structure of the micro-ring resonator MRR with a silicon-based electro-optic modulator in the electro-optic priority encoder of the present invention.

In the figure: 1. 1st microring resonator, 2. 2nd microring resonator, 3. 3rd microring resonator, 4. 4th microring resonator, 5. Si substrate, 6. SiO ₂ layer , 7. Heating electrode, 8. Silicon waveguide;

11. The first input optical waveguide, 12. The first straight-through optical waveguide, 21. The second input optical waveguide, 22. The third input optical waveguide, 23. The second straight-through optical waveguide, 24. The first download optical waveguide, 31 . The fourth input optical waveguide, 32. The fifth input optical waveguide, 33. The third straight-through optical waveguide, 34. The second download optical waveguide, 41. The sixth input optical waveguide, 42. The third download optical waveguide, 43. The first Four straight-through optical waveguides, 44. The fourth download optical waveguide.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the electro-optical priority encoder of the present invention includes:

The structure of the first microring resonator 1 shown in Figure 2, the first microring resonator 1 includes a first silicon-based nanowire microring l ₁ , a first input optical waveguide 11 and a first through optical waveguide 12; A microring resonator 1 with a silicon-based electro-optic modulator or a silicon-based thermo-optic modulator;

The structure of the second microring resonator ₂ shown in FIG. The straight-through optical waveguide 23 and the first download optical waveguide 24; the second input waveguide 21 is connected to the first straight-through optical waveguide 12; the second microring resonator 2 has a silicon-based electro-optic modulator or a silicon-based thermo-optic modulator;

The structure of the third microring resonator 3 shown in Figure 4, the third microring resonator 3 includes a third base nanowire microring ₁₃ , a fourth input optical waveguide 31, a fifth input optical waveguide 32, a third through The optical waveguide 33 and the second download optical waveguide 34; the fourth input waveguide 31 is connected with the second through optical waveguide 23 in the second microring resonator 2; the third microring resonator 3 has a silicon-based electro-optic modulator or silicon based thermo-optic modulator;

The structure of the fourth microring resonator 4 shown in Figure 5, the fourth microring resonator 4 includes a fourth silicon-based nanowire microring l ₄ , a sixth input optical waveguide 41, a fourth through optical waveguide 43, a third The download optical waveguide 42 and the fourth download optical waveguide 44; the sixth input optical waveguide 41 is connected with the third straight-through optical waveguide 33 in the third microring resonator 3; the third download optical waveguide 42 is connected with the second microring resonator 2 The third input optical waveguide 22 in is connected; The fourth download optical waveguide 44 is connected with the fifth input optical waveguide 32 in the third microring resonator 3; The fourth microring resonator 4 has a silicon-based electro-optic modulator or a silicon based thermo-optic modulator;

First input optical waveguide 11, first through optical waveguide 12, second input optical waveguide 21, second through optical waveguide 23, fourth input optical waveguide 31, third through optical waveguide 33, sixth input optical waveguide 41 and The fourth straight-through optical waveguide 43 is sequentially located on the first straight waveguide; the second download optical waveguide 34, the fifth input optical waveguide 32 and the fourth download optical waveguide 44 are successively located on the second straight waveguide, and the second straight waveguide is connected to the first straight waveguide. The straight waveguides intersect vertically, and the fifth input optical waveguide 32 and the fourth download optical waveguide 44 are respectively located on both sides of the first straight waveguide; the first straight waveguide and the second straight waveguide form a rectangular coordinate system, and the first silicon-based nanometer The wire microring ₁₁ and the second silicon-based nanowire microring ₁₂ are located in the third quadrant of the Cartesian coordinate system, and the first silicon-based nanowire microring ₁₁ is far away from the ordinate of the Cartesian coordinate system, and the third silicon-based nanowire The nanowire microring ₁₃ is located in the second quadrant of the Cartesian coordinate system, and the fourth silicon-based nanowire microring ₁₄ is located in the fourth quadrant of the Cartesian coordinate system; the first download optical waveguide 24, the third input optical waveguide 22 and The third download optical waveguide 42 is sequentially positioned on the third straight waveguide, the third straight waveguide is parallel to the first straight waveguide, the third straight waveguide and the second straight waveguide do not intersect, the second silicon-based nanowire microring ₁₂ and The _fourth silicon-based nanowire microring 14 is located in the area surrounded by the first straight waveguide and the third straight waveguide. The first straight waveguide, the second straight waveguide and the third straight waveguide are nanowire waveguides.

The electrodes of the microring resonator MRR with a silicon-based thermo-optic modulator, as shown in Figure 6, have a _SiO2 layer 6 grown on the Si substrate 5, and a silicon waveguide 8 made of SOI material is provided on the _SiO2 layer 6, A heating electrode 7 is also arranged on the SiO ₂ layer 6, a cavity is formed between the heating electrode 7 and the SiO ₂ layer 6, and a silicon waveguide 8 is located in the cavity; a voltage is applied to the leads of the heating electrode 7, and a current will pass through Heating the electrode 7 makes the heating electrode 7 generate heat, changing the temperature of the silicon-based optical waveguide through thermal radiation, thereby changing the effective group refractive index Ng of the ring _waveguide , and then changing the resonance wavelength of the MRR to realize dynamic filtering.

The electrode of the microring resonator MRR with a silicon-based electro-optic modulator is shown in Figure 7. The optical waveguide under this modulation mechanism is a pin structure, and the p-region and n-region doped at both ends are connected to high-speed electrodes. Applying a voltage to the electrode leads will generate an electric field from the positive electrode to the negative electrode in the optical waveguide, which will cause the drift movement of the carriers, thereby changing the carrier concentration in the silicon-based optical waveguide, thereby changing the ring waveguide The effective group refractive index N _g of the MRR changes the resonant wavelength of the MRR to realize dynamic filtering.

It can be seen that the modulation principles of the silicon-based thermo-optic modulator and the silicon-based electro-optic modulator are different. The silicon-based thermo-optic modulator relies on changing the temperature of the silicon-based optical waveguide to change the effective group refractive index of the waveguide. Silicon-based electro-optic modulators rely on changing the carrier concentration in the track optical waveguide to change the refractive index of the waveguide. The time taken by thermal radiation is much longer than the lifetime of non-equilibrium carriers. Therefore, the speed of electro-optic modulation is much faster than that of thermo-optic modulation, but because of the doping of waveguides, the structure of electro-optic modulators is more complicated than that of thermo-optic modulators, and the manufacturing process is also more complicated. Therefore, silicon-based electro-optic modulation is generally used when high speed is required, while silicon-based thermo-optic modulation is used when the response speed of the device is not high.

The structural parameters of the first silicon-based nanowire microring l ₁ , the second silicon-based nanowire microring l ₂ , the third silicon-based nanowire microring l ₃ , and the fourth silicon-based nanowire microring l ₄ are all the same. During modulation, the four silicon-based nanowire microrings all resonate at the same wavelength, which is the wavelength of the input optical signal.

Below by analyzing the light transmission process of the optical signal in the microring resonator shown in Fig. 2, Fig. 3, Fig. 4 and Fig. 5, briefly explain the working principle of the electro-optical priority encoder of the present invention:

For the first microring resonator 1 shown in Figure 2, it is assumed that the optical signal is input by the first input optical waveguide 11, when the optical signal passes through the coupling region (the first input optical waveguide 11, the first through optical waveguide 12 and the first When the silicon-based nanowire microring l ₁ is the closest range), the optical signal enters the first silicon-based nanowire microring l ₁ through evanescent field coupling, and the light in the first silicon-based nanowire microring l ₁ Signals are also coupled into the first straight-through optical waveguide 12 through evanescent field coupling. For an optical signal that satisfies the resonance condition (m×l=N _g ×2p×R, where N _g represents the group refractive index), when the microring is coupled to the first straight-through optical waveguide 12, due to the two optical signals The destructive interference caused by the phase difference will cause light extinction in the first straight optical waveguide 12; the light that does not satisfy the resonance condition cannot satisfy the destructive interference condition due to the phase difference, so the optical signal can be regarded as having no effect output from the first straight-through optical waveguide 12 through the coupling region;

For the second microring resonator 2 shown in Figure 3, it is assumed that the optical signal is input by the second input optical waveguide 21, when the optical signal passes through the coupling region (the second input optical waveguide 21, the second through optical waveguide 23 and the second silicon When the distance from the base nanowire microring l ₂ is the closest range), the optical signal enters into the second silicon based nanowire microring l ₂ through evanescent field coupling, and the optical signal in the second silicon based nanowire microring l ₂ It will also be coupled into the second through optical waveguide 23 and the first download optical waveguide 24 through evanescent field coupling. For an optical signal that satisfies the resonance condition (m×l=N _g ×2p×R), when coupled from the microring to the second straight-through optical waveguide 23, due to the phase difference between the two optical signals, the optical signal and the second input light The part of the waveguide 21 that is not coupled into the second silicon-based nanowire microring ₁₂ cancels out, so the light wave at the resonant wavelength cannot be detected in the second through waveguide 23, and the light wave of the corresponding wavelength will be downloaded to the first The output from the download optical waveguide 24 ; the light that does not satisfy the resonance condition can be regarded as output from the second straight-through optical waveguide 23 through the coupling region without any influence. When the optical signal is input from the third input optical waveguide 22, the optical signal enters into the second silicon-based nanowire microring ₁₂ through evanescent field coupling, and the optical signal in the second silicon-based nanowire microring ₁₂ also It is coupled into the second through optical waveguide 23 and the first download optical waveguide 24 through evanescent field coupling. For an optical signal that satisfies the resonance condition (m×l=N _g ×2p×R), when coupled from the microring to the first downloading optical waveguide 24, due to the phase difference between the two optical signals, the optical signal and the third input light The part of the waveguide 22 that is not coupled into the second silicon-based nanowire microring ₁₂ cancels out, so the light wave at the resonant wavelength cannot be detected in the first downloading optical waveguide 24, and the light wave at the corresponding wavelength will be downloaded to the second downloading waveguide 24. output through the optical waveguide 23; the light that does not satisfy the resonance condition can be regarded as output from the first downloading optical waveguide 24 through the coupling region without any influence;

For the third microring resonator 3 shown in Figure 4, it is assumed that the optical signal is input by the fourth input optical waveguide 31, when the optical signal passes through the coupling region (the fourth input optical waveguide 31, the third through optical waveguide 33 and the third silicon When the distance between the base nanowire microring l ₃ is the closest range), the optical signal enters into the third silicon based nanowire microring l ₃ through evanescent field coupling, and the optical signal in the third silicon based nanowire microring l ₃ It will also be coupled into the third through optical waveguide 33 and the second download optical waveguide 34 through evanescent field coupling. For an optical signal that satisfies the resonance condition (m×l=N _g ×2p×R), when coupled from the microring to the third straight-through optical waveguide 33, due to the phase difference between the two optical signals, the optical signal and the fourth input light The part of the waveguide 31 that is not coupled into the third silicon-based nanowire microring ₁₃ cancels out, so the light wave at the resonant wavelength cannot be detected in the third straight-through optical waveguide 33, and the light wave at the corresponding wavelength will be downloaded to the second The output from the download optical waveguide 34; the light that does not meet the resonance condition can be regarded as output from the third straight-through optical waveguide 33 through the coupling region without any influence. And when the optical signal is input from the fifth input optical waveguide 32, the optical signal enters the third silicon-based nanowire microring ₁₃ through evanescent field coupling, and the optical signal in the third silicon-based nanowire microring ₁₃ also will be coupled into the third through optical waveguide 33 and the second download optical waveguide 34 through evanescent field coupling. For an optical signal that satisfies the resonance condition (m×l=N _g ×2p×R), when coupled from the microring to the second downloading optical waveguide 34, due to the phase difference between the two optical signals, the optical signal and the fifth input light The part of the waveguide 32 that is not coupled into the third silicon-based nanowire microring ₁₃ cancels out, so the light wave at the resonant wavelength cannot be detected in the second downloading optical waveguide 34, and the light wave at the corresponding wavelength will be downloaded to the third downloading waveguide 34. output through the optical waveguide 33; the light that does not meet the resonance condition can be regarded as output from the second downloading optical waveguide 34 through the coupling region without any influence.

For the fourth microring resonator 4 shown in Fig. 5, it is assumed that the optical signal is input by the sixth input optical waveguide 41, when the optical signal passes through the coupling region (the sixth input optical waveguide 41, the fourth through optical waveguide 43 and the fourth silicon When the distance between the base nanowire microring 1 and ₄ is the closest range), the optical signal enters into the fourth silicon-based nanowire microring 1 ₄ through evanescent field coupling, and the optical signal in the fourth silicon-based nanowire microring 1 ₄ It will also be coupled into the third downloading optical waveguide 42 and the fourth downloading optical waveguide 44 through evanescent field coupling. Similarly, the light wave satisfying the resonant wavelength will be completely downloaded by the microring, since the third downloading optical waveguide 42 and the fourth downloading optical waveguide 44 are equivalent to the fourth silicon-based nanowire microring ₁₄ , so the fourth The silicon-based nanowire microring ₁₄ will divide the optical power of the input optical signal into two parts and output it from the third optical waveguide 42 and the fourth optical waveguide 44 respectively; The unaffected through-coupling region is output from the fourth through-optical waveguide 43 .

The above analysis is the working characteristics of the static microring resonator. In summary, the microring resonator will fix the signals of certain wavelengths (wavelengths that meet the resonance conditions) to be downloaded, and the signals of certain wavelengths to pass through (not satisfying the resonance conditions). The wavelength of the condition); when the device is working, the resonant wavelength of the microring resonator is also required to be dynamically adjustable. It can be seen from the resonance condition ( m×l=N _g ×2p× R ) that changing the radius R of the silicon-based nanowire microring and the effective group refractive index N _g will change the resonance wavelength of the silicon-based nanowire microring. Here, the resonant wavelength of the silicon-based nanowire _microring is changed by adjusting the effective group refractive index Ng of the microring waveguide. The effective group refractive index is related to the refractive index of the silicon-based nanowire microring material, and there are two ways to change the material’s refractive index: one is to heat the material, change the temperature of the material, and use the thermo-optic effect to change the material’s refractive index. That is, the above-mentioned silicon-based thermo-optic modulator; the second is to use the electro-optic effect to change the refractive index of the material through carrier injection, that is, the above-mentioned silicon-based electro-optic modulator. Since the thermal modulation speed is affected by the thermal convection speed, and the electrical modulation speed depends on the carrier lifetime, the electrical modulation speed is faster, and electrical modulation is used in high-speed systems.

Taking the thermal modulation mechanism as an example to illustrate the working process of the electro-optical priority encoder of the present invention:

A continuous and stable optical signal at a working wavelength is input to the first input optical waveguide 11 of the first microring resonator 1 . Then load the electrical signal to be encoded on the thermal modulation mechanism of each microring resonator. When the electrical signal is encoded as a low level, that is, logic "0", no current passes through the electrodes of the thermo-optic modulator, and no Thermal effect, the refractive index of the optical waveguide is not affected; when the electrical signal is coded to a high level, that is, logic "1", under the action of an electric field, a current passes through the electrode of the thermo-optic modulator, generating a thermal effect, through thermal radiation The heating effect is exerted on the optical waveguide, so the refractive index of the optical waveguide changes, so that the resonant wavelength of the microring resonator can be changed.

If the state of a certain microring resonator is logic '0' when the modulation electrical signal is at a low level, the microring resonator resonates at this time. When the modulated electrical signal is at a high level, the state is logic '1', and the microring resonator does not resonate at this time; if the output port has an optical signal output, it is represented by a logic '1', and when there is no optical signal output at the output port, it is represented by a logic '0'' means that each microring resonator has two states of '0' and '1', for various states combined, in three output ports, i.e. the first download optical waveguide 24, the second download optical waveguide 34 and the fourth straight-through optical waveguide 43 have corresponding optical signal output states corresponding thereto. Note that the logic value of the electrical signal loaded on the thermal modulation mechanism of the first microring resonator 1 is I ₁ , and the logic value of the electrical signal loaded on the thermal modulation mechanism of the second microring resonator 2 is I ₂ . The logical value of the electrical signal on the thermal modulation mechanism of the third microring resonator 3 is I ₃ , and the logical value of the electrical signal loaded on the thermal modulation mechanism of the fourth microring resonator 4 is I ₄ , and the logical value of the first downloading optical waveguide 24 is recorded. The output optical signal is denoted as Y ₁ , the output optical signal of the second download optical waveguide 34 is denoted as Y ₂ , and the output optical signal of the fourth straight-through optical waveguide 43 is denoted as A .

The electrical signals loaded by the priority encoder are I ₁ , I ₂ , I ₃ , and I ₄ . The corresponding I ₁ is loaded on the silicon-based thermo-optic modulator of the silicon-based nanowire microring l ₁ , I ₂ is loaded on the silicon-based thermo-optic modulator of the silicon-based nanowire microring l ₂ , and I ₃ is loaded on the silicon-based The nanowire microring l3 is _on the silicon _- based thermo-optic modulator, and I4 is loaded _on the silicon-based thermo-optic modulator of the silicon-based nanowire microring l4 . The order of priority is determined by the position order of each microring, which determines the order in which optical signals arrive at each microring, the higher the order, the higher the priority; thus achieving the purpose of priority coding . Therefore, the priority corresponding to this priority encoder is I ₁ >I ₂ >I ₃ >I ₄ .

When I ₁ is at a low level ( I ₁ =0), corresponding to the first microring resonator 1 resonating at the wavelength of the input light wave, it can be seen from the analysis of Figure 2 that the light wave of this wavelength will be extinguished in the coupling region, that is, the first The optical signal in the straight-through optical waveguide 12 is '0', and the optical signal power in the second input optical waveguide 21 in the second microring resonator 2 is '1', so no matter what I ₂ , I ₃ , or I ₄ are state, the output ports Y ₁ and Y ₂ cannot detect light wave output ( Y ₁ = Y ₂ =0);

When I ₁ is at a high level ( I ₁ =1), the corresponding first microring resonator 1 is modulated, and its resonance wavelength deviates from the wavelength of the light wave, so the input light wave continues to propagate forward, and the light in the first straight-through optical waveguide 12 The signal power is '1', the optical signal power in the second input optical waveguide 21 in the second microring resonator 2 is '1', when I ₂ is low level ( I ₂ =0), corresponding to the second microring The resonator 2 resonates at the wavelength of the input light wave. According to the analysis of FIG. 3 , the optical power in the second through optical waveguide 23 is '0', while the optical signal power in the first download optical waveguide 24 is '1'. Therefore, no matter what state I ₃ and I ₄ are in, the input light wave will be completely downloaded by the second microring resonator 2 and output from the Y ₁ port ( Y ₁ =1, Y ₂ =0).

When I ₁ and I ₂ are at a high level ( I ₁ =1, I ₂ =1), the corresponding first microring resonator 1 and the second microring resonator 2 are both modulated, and the resonance wavelength of the microring deviates from the light wavelength, Therefore, the input optical wave continues to propagate forward, and the optical signal power in the fourth input optical waveguide 31 of the third microring resonator 3 is '1'. When I ₃ is at a low level ( I ₃ =0), corresponding to the third microring resonator 3 resonating at the wavelength of the input light wave, it can be seen from the analysis of accompanying drawing 4 that the power of the optical signal in the third direct optical waveguide 33 is '0', the power of the optical signal in the second download optical waveguide 34 is '1'. No matter what state I ₄ is in, the input light wave will be completely downloaded by the third microring resonator 3 and output from the Y ₂ port ( Y ₁ =0, Y ₂ =1).

When I ₁ , I ₂ , and I ₃ are at high level ( I ₁ =1, I ₂ =1, I ₃ =1), corresponding to the first microring resonator 1, the second microring resonator 2 and the third microring resonator The ring resonator 3 is modulated, and the resonant wavelengths of the three microring resonators deviate from the wavelength of the light wave, so the input light wave continues to propagate forward, and the power of the optical signal in the sixth input optical waveguide 41 of the fourth microring resonator 4 is '1'. When I ₄ is low level ( I ₄ =0), the corresponding fourth microring resonator 4 resonates at the wavelength of the input light wave. From the analysis of Figure 5, it can be known that the input light wave will be downloaded by the microring and divided into two parts Simultaneously output by the third downloading optical waveguide 42 and the fourth downloading optical waveguide 44, the power of the optical signal in the third downloading optical waveguide 42 and the fourth downloading optical waveguide 44 is '1'. Since the second microring resonator 2 and the third microring resonator 3 are not resonant at this time, the optical signals input from the third input optical waveguide 22 and the fifth input optical waveguide 32 will pass through and be transmitted by the first download optical waveguide 24 and the second downloading optical waveguide 34 output, and finally output from Y ₁ and Y ₂ ports ( Y ₁ = Y ₂ =1).

If I ₁ , I ₂ , I ₃ , and I ₄ are all at high level ( I ₁ =1, I ₂ =1, I ₃ =1, I ₄ =1), the corresponding first microring resonator 1, the first The second microring resonator 2, the third microring resonator 3 and the fourth microring resonator 4 are all modulated, and the input light wave will be directly output from the straight-through optical waveguide, and finally output by the A port ( A = 1, Y ₁ = Y ₂ =0). At this time, the electro-optical priority encoder of the present invention is not working.

According to the above working state description, make the logic truth table of the 4-wire-2-wire electro-optic priority encoder shown in Table 1.

Table 1 The logic truth table of this 4-wire-2-wire electro-optical priority encoder

It can be seen from Table 1 that when the logic value of A output is 1, the electro-optical priority encoder is not in working state, only when the logic output value of A is 0, the optical logic value detected from Y ₁ and Y ₂ can be used as Result of device encoding. Table 1 intuitively illustrates that the electro-optic priority encoder of the present invention can realize the priority encoding operation of 4-2 lines. According to the rule of priority I ₁ >I ₂ >I ₃ >I ₄ in the present invention, the output result is represented by the optical logic value detected by Y ₁ and Y ₂ .

In the electro-optic priority encoder of the present invention, the first input optical waveguide 11 of the first microring resonator 1 inputs a continuous constant fixed wavelength optical signal; according to the arrangement order of the four microring resonators, the first microring resonator 1 The high and low level electrical signals to be encoded are loaded in the priority order that the second microring resonator 2 is higher than the third microring resonator 3 and higher than the fourth microring resonator 4, and the electrical signals to be encoded act on the Each corresponds to a microring; when the voltage signal is at a high level, each microring resonator is detuned at the input optical wavelength, and the optical signal passes through; when the voltage signal is at a low level, each microring resonator resonates at the input optical wavelength, and the corresponding wavelength The optical signal is downloaded by the microring. Therefore, the electro-optical priority encoder of the present invention allows multiple signals to be input at the same time, and the priority encoder only encodes the signal with the highest priority, which greatly improves the error tolerance rate of the encoder and improves the working stability. The optical signals output by the downloading optical waveguide in the second microring resonator 2 and the downloading optical waveguide in the third microring resonator 3 together form the final encoding result of the electro-optic priority encoder, and the output encoding result can be directly input into the following The first-level operation or pass into the photodetector to read out the encoding result.

The 4-wire-2-wire electro-optical priority encoder of the present invention is realized by 4 micro-ring resonators MRR and 3 nanowire waveguides made of semiconductor material on an insulator. The input is four high- and low-level electrical signals to be encoded and a continuous laser signal at the working wavelength, and the output is two optical signals encoded by the electrical signals. The basic unit of each microring resonator MRR is a microring resonator MRR optical switch with a thermal modulation mechanism or an electrical modulation mechanism. The 4-bit electrical signal to be encoded acts on the respective MRR as follows: When the modulation electrical signal is at a high level, the resonant frequency of the MRR shifts and detunes at the wavelength of the input laser; when the modulation electrical signal applied to the microring is at a low level, the MRR resonates at the wavelength of the input laser, and the light The signal is downloaded. The encoding process is: input a continuous laser with a specific working wavelength at an optical port of the device, and the 4-bit high and low level electrical signals to be encoded act on the 4 MRRs according to the determined priority order, and the optical signals are output at the two signal output ports. In the form of logic, the encoding result corresponding to the 4-bit input electrical signal is output, thereby completing the 4-wire-2-wire priority encoding function. This encoder has a specific priority, and when there are multiple input signals at the same time, only the signal with the highest priority is encoded.

This electro-optical priority encoder overcomes the bottleneck problems of speed, power consumption, gate delay, competition and risk in traditional electrical encoders, and maintains the modern integrated circuit premise of small device size, low power consumption and easy integration. It plays an important role in photonic communication and photonic information processing systems.

The specific examples described above are only further detailed descriptions of the purpose, technical solutions and beneficial effects of the present invention. It should be pointed out that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (1)

1. A novel 4-wire-2-wire electro-optic priority encoder based on a microring resonator, characterized in that it comprises a first microring resonator (1), a second microring resonator (2), a third microring resonator The resonator (3), the fourth microring resonator (4), the first straight waveguide, the second straight waveguide and the third straight waveguide, the first straight waveguide and the second straight waveguide intersect perpendicularly to form a rectangular coordinate system, the first straight waveguide The three straight waveguides are parallel to the first straight waveguide, and the third straight waveguide does not intersect with the second straight waveguide; The first microring resonator (1) includes a first silicon-based nanowire microring ( l ₁ ), a first input optical waveguide (11) and a first straight-through optical waveguide (12); the first silicon-based nanowire microring ( l ₁ ) Located in the third quadrant of the Cartesian coordinate system, the first microring resonator (1) has a silicon-based electro-optic modulator or a silicon-based thermo-optic modulator; the first input optical waveguide (11) and the first through-light The waveguides (12) are all located on the first straight waveguide, and the first input optical waveguide (11) is far away from the second straight waveguide, and the first straight optical waveguide (12) is connected to the second microring resonator (2); The second microring resonator (2) includes a second silicon-based nanowire microring ( l ₂ ), a second input optical waveguide (21), a third input optical waveguide (22), a second through optical waveguide (23) and The first download optical waveguide (24); the second silicon-based nanowire microring ( l ₂ ) is located in the third quadrant of the Cartesian coordinate system, and is located between the first straight waveguide and the third straight waveguide; the second input optical waveguide (21 ) and the second straight-through optical waveguide (23) are sequentially located on the first straight waveguide along the direction toward the second straight waveguide, the second input waveguide (21) is connected to the first straight-through optical waveguide (12); the first download optical waveguide (24) and the third input optical waveguide (22) are sequentially located on the third straight waveguide along the direction toward the second straight waveguide, the second straight optical waveguide (23) is connected with the third microring resonator (3), and the third The input optical waveguide (22) is connected to the fourth microring resonator (4), and the second microring resonator (2) has a silicon-based electro-optic modulator or a silicon-based thermo-optic modulator; The third microring resonator (3) includes a third silicon-based nanowire microring ( l ₃ ), a fourth input optical waveguide (31), a fifth input optical waveguide (32), a third through optical waveguide (33) and The second download optical waveguide (34); the third silicon-based nanowire microring ( l ₃ ) is located in the second quadrant of the Cartesian coordinate system, the fourth input optical waveguide (31) and the third through optical waveguide (33) are The directions of the two straight waveguides are sequentially located on the first straight waveguide, the fourth input waveguide (31) is connected to the second straight waveguide (23); the fifth input waveguide (32) and the second download waveguide (34) are separated along the The direction of the first straight waveguide is sequentially located on the second straight waveguide, the fifth input optical waveguide (32) and the third straight optical waveguide (33) are connected to the fourth microring resonator (4), the third microring resonator (3) With a silicon-based electro-optic modulator or a silicon-based thermo-optic modulator; The fourth microring resonator (4) includes a fourth silicon-based nanowire microring ( l ₄ ), a sixth input optical waveguide (41), a fourth straight-through optical waveguide (43), a third download optical waveguide (42) and The fourth download optical waveguide (44); the fourth silicon-based nanowire microring ( l ₄ ) is located in the fourth quadrant of the Cartesian coordinate system; the sixth input optical waveguide (41) and the fourth through optical waveguide (43) are along the The directions of the two straight waveguides are sequentially located on the first straight waveguide; the fourth download optical waveguide (44) is located on the second straight waveguide, the third download optical waveguide (42) is located on the third straight waveguide; the sixth input optical waveguide (41 ) is connected to the third straight-through optical waveguide (33); the third download optical waveguide (42) is connected to the third input optical waveguide (22); the fourth download optical waveguide (44) is connected to the fifth input optical waveguide (32); The fourth microring resonator (4) has a silicon-based electro-optic modulator or a silicon-based thermo-optic modulator.